An in vitro investigation of the acetabular labral seal in hip joint mechanics

Labral Augmentation With Either Iliotibial Band Allograft or Dermis Allograft Perform Similarly Regarding Peak Force, Displacement, and Work to Labral Repair in Suction Seal Restoration: A Biomechanical Study

PURPOSE

To investigate whether allograft substitutes may be used to restore suctional seal properties with labral augmentation, the purpose of the current study was to evaluate the biomechanical properties of the labral suction seal under several scenarios, including: (1) intact labrum, (2) rim preparation, (3) labral repair, (4) labral augmentation with iliotibial band (ITB), and (5) labral augmentation with a dermis allograft.

METHODS

Eleven hemi-pelvises were dissected to the level of the labrum and placed in a material testing system for biomechanical axial distraction. Each specimen was compressed to 250 newtons (N) and distracted at 10 mm/s while load, crosshead displacement, and time were continuously recorded. For each of the 5 labral states, 3 testing repetitions were performed. Peak force (N, newtons), displacement at peak force (mm, millimeter), and work (N-mm, newton, millimeter) were calculated and normalized to the intact state of each specimen.

RESULTS

Eleven specimens were tested and 8 specimens (age: 58.6 ± 5.4 years, body mass index: 28.6 ± 6.8 kg/m2; 4 female patients; 5 right hips) were included in final analyses. Expressed as a percentage relative to the intact state, the average normalized peak force, displacement at peak force, and work for each labral state were as follows: intact (100.0% ± 0% for all), rim preparation (89.0% ± 9.2%, 93.3% ± 20.6%, 85.1% ± 9.0%), repair (61.3% ± 17.9%, 88.4% ± 36.9%, 58.1% ± 16.7%), ITB allograft (62.7% ± 24.9%, 83.9% ± 21.6%, 59.4% ± 22.4%), and dermis allograft (57.8% ± 27.2%, 88.2% ± 29.5%, 50.0% ± 20.1%). Regarding peak force, intact state was significantly greater compared with the labral repair, augmentation with ITB, and augmentation with the dermis allograft states (P < .001). No significant differences were demonstrated between displacement at peak force (P = .561). Regarding work, both intact state and rim preparation states were significantly greater than the repair, ITB augmentation, and dermis allograft augmentation states (P < .001). In all outcome measures, the dermis allograft augmentation performed with no statistical difference to the ITB augmentation state.

CONCLUSIONS

Labral repair and labral augmentation with either ITB allograft or the dermis allograft resulted in significantly lower peak force and work to equilibrium compared with the intact and rim prep states. There was no statistical difference between repair and augmentation states as well as no statistical difference between ITB allograft and dermal allograft at time zero.

CLINICAL RELEVANCE

This study compares biomechanical properties of the suction seal of the hip comparing labral states including intact, rim preparation, repair, and augmentation, which can be used for surgical decision-making.

Editorial Commentary: Prevention and Treatment of Hip Adhesions Associated With Hip Arthroscopy Shows Positive Outcomes

Adhesions are known to occur following arthroscopic as well as open surgery of multiple joints, including after hip arthroscopy, resulting in pain, stiffness, and dysfunction. Adhesions of the labrum to the overlying hip capsule can lead to eversion of the labrum and potentially compromise the suction seal, leading to microinstability and pain. Generally, patient-reported outcomes improve after surgical lysis of adhesions, with or without concurrent correction of labral, chondral, or bony pathology. Arthroscopic placement of autograft or allograft spacers may be effective when adhesions between the labrum and capsule prevent an adequate suction seal. Prevention using biologics, such as angiotensin II receptor blockers (e.g., losartan), may inhibit transforming growth factor β1, which has been associated with fibrogenesis, tissue fibrosis, and scarring. Side effects of losartan are rare but include hypotension, dizziness, angioedema, and acute kidney injury when coprescribed with nonsteroidal anti-inflammatory drugs, which are often used in heterotopic ossification prophylaxis in hip arthroscopy and are a significant concern. More data on losartan use are required prior to broader adoption.

The Contribution of Soft Tissue and Bony Stabilizers to the Hip Suction Seal: A Systematic Review of Biomechanical Studies

BACKGROUND

Previous biomechanical studies have identified capsular closure, labral repair or reconstruction, and osteochondroplasty as important surgical interventions to improve hip stability.

PURPOSE

To investigate the outcome metrics used to quantify hip stability and assess and measure the relative contributions of the labrum, capsule, and bone to hip stability through a quantitative analysis.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 4.

METHODS

PubMed and Embase databases were searched using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Included studies evaluated cadaveric hip biomechanics related to capsular, labral, and bony management during hip arthroscopy. Studies were assessed for distraction force and distance, fluid measures, and contact forces used to quantify the suction seal. Exclusion criteria included open surgery, arthroplasty, reorientation osteotomy, or traumatic dislocation.

RESULTS

A total of 33 biomechanical studies comprising 322 hips that evaluated 1 or more of the following were included: distraction force or distance (24 studies), fluid measures (10 studies), and contact forces (6 studies). Compared with a capsulotomy or capsulectomy, capsular repair or reconstruction demonstrated greater resistance to distraction (standardized mean difference [SMD], 1.13; 95% CI, 0.46-1.80; P = .0009). Compared with a labral tear, a labral repair or reconstruction demonstrated less resistance to distraction (SMD, -0.67; 95% CI, -1.25 to -0.09; P = .02). Compared with a labral debridement, repair or reconstruction demonstrated greater resistance to distraction (SMD, 1.74; 95% CI, 1.23 to 2.26; P < .00001). No quantitative analysis was feasible from studies evaluating the effect of osseous resection due to the heterogeneity in methodology and outcome metrics assessed.

CONCLUSION

Most biomechanical evidence supports capsulotomy repair or reconstruction to improve hip distractive stability at the end of hip arthroscopic surgery. While the repair of a torn labrum does not improve distractive resistance, it is superior to labral debridement in most biomechanical studies.

Primary Total Hip Arthroplasty Outcomes for Labral Tears are Comparable to Advanced Osteoarthritis

BACKGROUND

There is a paucity of evidence on outcomes following total hip arthroplasty (THA) in patients who have symptomatic degenerative labral tears and mild to moderate osteoarthritis (OA). The purpose of this study was to determine if outcomes of primary THA in the setting of painful, symptomatic labral tear and mild to moderate arthritic changes were comparable to outcomes of primary THA performed for severe arthritic changes. Primary outcomes were patient-reported outcome (PRO) scores. Secondary outcomes included length of stay and perioperative complications.

METHODS

This was a retrospective investigation of all THAs between January 2018 and July 2022. There were 111 patients who had THA due to failure of nonoperative treatment of a degenerative labral tear without advanced arthritic changes (mild to moderate OA cohort, Kellgren-Lawrence Grades 1 to 3). These patients were matched to 111 patients who underwent THA for advanced OA (AOA cohort, Kellgren-Lawrence Grade 4). PROs included the Western Ontario McMaster Universities Arthritis Index (WOMAC). The average age for the labral tear cohort was 59 years, with 50.6% women, compared to 70 years (P < 0.001), and 49.4% women (P = 0.93) in the AOA cohort.

RESULTS

There were no differences in preoperative PROs, complications, or length of stay between groups. When looking at postoperative PROs between cohorts, the labral tear cohort had less improvement in WOMAC-Stiffness (24.3 versus 34.0, P = 0.005) and WOMAC-Functional limitation (26.3 versus 36.0, P = 0.005) at 12 months and greater improvement in WOMAC-Pain at 12 months (38.3 versus 34.7, P = 0.04). The Short Form 12-Physical function scores were significantly higher among the labral tear cohort compared to the AOA cohort at 12 months (48.5 versus 47.8, P < 0.001). The Short Form 12-Mental scores were significantly higher in the AOA cohort compared to the labral tear cohort at 3 months (47.1 versus 47.4, P = 0.02) and 12 months (46.7 versus 47.6, P < 0.001). In the multivariate analysis, the change in WOMAC-Pain at 12 months was significantly better for labral tear patients (odds ratio 7.5, P = 0.008, confidence interval 6.85 to 8.14).

CONCLUSIONS

Our study showed that patients who have symptomatic degenerative labral tears with mild to moderate arthritic changes have comparable outcomes to patients who have AOA following primary THA. Given suboptimal outcomes with hip arthroscopy for labral tear in the setting of early arthritis, primary THA can be a reasonable treatment modality for patients failing nonoperative treatments.

Indirect Head of the Rectus Femoris Tendon as a Graft for Segmental Hip Labral Reconstruction: An Anatomic, Radiographical, and Biomechanical Study in Comparison With Iliotibial Labral Reconstruction

BACKGROUND

The indirect head of the rectus femoris (IHRF) tendon has been used as an autograft for segmental labral reconstruction. However, the biomechanical properties and anatomic characteristics of the IHRF, as they relate to surgical applications, have yet to be investigated.

PURPOSE

To (1) quantitatively and qualitatively describe the anatomy of IHRF and its relationship with surrounding arthroscopically relevant landmarks; (2) detail radiographic findings pertinent to IHRF; (3) biomechanically assess segmental labral reconstruction with IHRF, including restoration of the suction seal and contact pressures in comparison with iliotibial band (ITB) reconstruction; and (4) assess potential donor-site morbidity caused by graft harvesting.

STUDY DESIGN

Descriptive laboratory study.

METHODS

A cadaveric study was performed using 8 fresh-frozen human cadaveric full pelvises and 7 hemipelvises. Three-dimensional anatomic measurements were collected using a 3-dimensional coordinate digitizer. Radiographic analysis was accomplished by securing radiopaque markers of different sizes to the evaluated anatomic structures of the assigned hip.Suction seal and contact pressure testing were performed over 3 trials on 6 pelvises under 4 different testing conditions for each specimen: intact, labral tear, segmental labral reconstruction with ITB, and segmental labral reconstruction with IHRF. After IHRF tendon harvest, each full pelvis had both the intact and contralateral hip tested under tension along its anatomic direction to assess potential site morbidity, such as tendon failure or bony avulsion.

RESULTS

The centroid and posterior apex of the indirect rectus femoris attachment are respectively located 10.3 ± 2.6 mm and 21.0 ± 6.5 mm posteriorly, 2.5 ± 7.8 mm and 0.7 ± 8.0 mm superiorly, and 5.0 ± 2.8 mm and 22.2 ± 4.4 mm laterally to the 12:30 labral position. Radiographically, the mean distance of the IHRF to the following landmarks was determined as follows: anterior inferior iliac spine (8.8 ± 2.5 mm), direct head of the rectus femoris (8.0 ± 3.9 mm), 12-o'clock labral position (14.1 ± 2.8 mm), and 3-o'clock labral position (36.5 ± 4.4 mm). During suction seal testing, both the ITB and the IHRF reconstruction groups had significantly lower peak loads and lower energy to peak loads compared with both intact and tear groups (P = .01 to .02 for all comparisons). There were no significant differences between the reconstruction groups for peak loads, energy, and displacement at peak load. In 60° of flexion, there were no differences in normalized contact pressure and contact area between ITB or IHRF reconstruction groups (P > .99). There were no significant differences between intact and harvested specimen groups in donor-site morbidity testing.

CONCLUSION

The IHRF tendon is within close anatomic proximity to arthroscopic acetabular landmarks. In the cadaveric model, harvesting of the IHRF tendon as an autograft does not lead to significant donor-site morbidity in the remaining tendon. Segmental labral reconstruction performed with the IHRF tendon exhibits similar biomechanical outcomes compared with that performed with ITB.

CLINICAL RELEVANCE

This study demonstrates the viability of segmental labral reconstruction with an IHRF tendon and provides a detailed anatomic description of the tendon in the context of an arthroscopic labral reconstruction. Clinicians can use this information during the selection of a graft and as a guide during an arthroscopic graft harvest.

Preoperative Paralabral Cysts Predict More Significant Chondral Damage but Not 2-Year Functional Outcomes Following Arthroscopic Labral Repair

PURPOSE

To investigate whether paralabral cysts identified incidentally on preoperative magnetic resonance imaging/arthrography predict 2-year functional outcomes after arthroscopic acetabular labral repair.

METHODS

Prospectively collected data for patients undergoing primary hip arthroscopy by a single surgeon from 2014 to 2020 were retrospectively reviewed. Included patients were ≥18 years and completed baseline patient-reported outcome measures (PROMs) with additional follow-up at 3, 6, 12, and 24 months. Exclusion criteria were labral debridement, hip dysplasia, advanced hip osteoarthritis (Tönnis > 1), or previous ipsilateral hip surgery. Patients were stratified based on the presence of paralabral cysts identified on magnetic resonance imaging/arthrography. Primary outcomes were International Hip Outcome Tool and modified Harris Hip Score. Secondary outcomes included other PROMs and the visual analog pain scale. Outcomes were compared between cohorts using linear mixed-effects models and Fisher's exact tests. Sensitivity analyses accounted for preoperative PROMs, nonlinear improvement trajectories, and relevant baseline characteristics.

RESULTS

Of the 182 included hips (47.8% female; mean ± standard deviation age, 36.9 ± 11.4), 30 (16.4%) had paralabral cysts. During the 2-year study period, there were no significant differences between patients with and without paralabral cysts in terms of International Hip Outcome Tool scores (weighted difference = 1.60; 95% confidence interval [CI], -5.09, 8.28; P = .64), modified Harris Hip Scores (weighted difference = 0.56; 95% CI, -4.16, 5.28; P = .82), or any secondary outcomes (except for HOS-Sports Subscale at 3 months [mean difference = -11.85; 95% CI, -22.85, -0.84; P = .035]). Furthermore, there were no significant differences in clinically meaningful outcomes (P > .05 for all), revision rates (P > .99), or conversion to total hip arthroplasty between cohorts (P > .99). These results held across all sensitivity analyses.

CONCLUSIONS

Although preoperative paralabral cysts were associated with worse cam impingement and more severe chondral damage observed intraoperatively, they did not predict 2-year functional outcomes or clinically meaningful improvements, suggesting that incidentally discovered paralabral cysts are not a contraindication for arthroscopic labral repair.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

The Role of the Hip Capsule in Restoring Stability in the Initial Phase of Hip Distraction: An In Vivo Analysis

Background

The labral suction seal has been shown to provide the majority of resistance in the initial phase of hip distraction. However, the effect of an unrepaired interportal capsulotomy and capsular repair on the initial phase of hip distractive stability in vivo is not well understood.

Purpose

To investigate the effect of capsular repair on the initial phase of distractive stability of hip joints in patients with femoroacetabular impingement (FAI) syndrome.

Study Design

Controlled laboratory study.

Methods

Patients undergoing primary hip arthroscopy for FAI between March and August 2020 were prospectively enrolled. Total joint space was measured on fluoroscopic images at the medial and lateral edges of the sourcil at 12.5-lb (5.7-kg) axial traction intervals (up to 100 lb [45.4 kg]) in 3 capsular states: (1) native capsule, (2) interportal capsulotomy, and (3) capsular repair. Distraction on anteroposterior radiographs was calculated as the difference between total joint space at each traction interval and baseline joint space at 0 lb, normalized to millimeters. The native, capsulotomy, and capsular repair states were compared using Wilcoxon signed-rank and McNemar tests.

Results

Included were 36 hips in 35 patients. The median force required to distract ≥3 mm was 75 lb (34.0 kg; 95% CI, 70-80 lb [31.8-36.3 kg]) in both the native and capsular repair states (P = .629), which was significantly greater than the median force required to distract ≥3 mm in the capsulotomy state (50 lb [22.7 kg]; 95% CI, 45-55 lb [20.4-24.9 kg]) (P < .001). The most rapid rates of change in joint space were observed at the traction interval at which hips first achieved ≥3 mm of distraction (n = 33 hips; 92%).

Conclusion

The traction force at which hips distracted ≥3 mm was 75 lb (34.0 kg) in both the native capsular and capsular repair states. Significantly less traction force (50 lb [22.7 kg]) distracted hips ≥3 mm in the capsulotomy state. Complete capsular closure after interportal capsulotomy resulted in restoration of initial distractive stability relative to the unrepaired capsulotomy state at time zero after primary hip arthroscopy.

Clinical Relevance

This study provides surgeons with an improved understanding of the additional stability to the hip joint from capsular repair after hip arthroscopy for FAI syndrome.

The Windshield Wiper Sign Is an Instability-Related Osteochondral Defect of the Anterolateral Femoral Head

PURPOSE

To investigate a radiographic sign believed to be indicative of hip instability and acetabular suction seal disruption in the native hip, coined the "windshield wiper" (WSW) sign.

METHODS

A retrospective review was performed for patients who underwent periacetabular osteotomy (PAO) with the senior author between March 2021 and September 2023. A WSW sign was identified on plain films as a concave or flat osteochondral defect on the anterolateral femoral head extending medial to the head-neck junction with resultant loss of femoral head sphericity in the native hip. Every patient underwent a standardized series of radiographs, as well as computed tomography and magnetic resonance imaging. All patients underwent arthroscopy before PAO to address intra-articular pathology and other indicated procedures. The osteochondral defect and resultant suction seal disruption were verified during arthroscopy. These patients were then compared with a control group of arthroscopically treated hips without hip instability.

RESULTS

Of 250 patients reviewed, a total of 19 hips in 17 patients (prevalence of 7.6%) demonstrated radiographic evidence of the WSW sign. All patients with a WSW sign presented with symptomatic clinical hip instability requiring a PAO. The mean patient age was 31.2 years, with a mean lateral center-edge angle (LCEA) of 14.3°. There were 13 hips (68.4%) with dysplasia, 4 (21.1%) with borderline dysplasia, and 2 (10.5%) with a normal LCEA. All patients with a WSW sign and LCEA ≥ 20° displayed significant femoral antetorsion abnormalities. All arthroscopic videos and images demonstrated a compromised suction seal. Of the 50 control group hips reviewed, the WSW sign was not identified.

CONCLUSIONS

The WSW sign is an uncommon radiographic finding in patients with hip instability. When identified, it can be predictive of substantial instability, especially in cases which are otherwise considered borderline dysplasia or normal based on LCEA.

LEVEL OF EVIDENCE

Level III, retrospective comparative case control study.

Association Between Chondrolabral Junction Breakdown and Conversion to Total Hip Arthroplasty After Hip Arthroscopy for Symptomatic Labral Tears: Minimum 8-Year Follow-up

BACKGROUND

Arthroscopic treatment of femoroacetabular impingement (FAI) and symptomatic labral tears confers short- to midterm benefits, yet further long-term evidence is needed. Moreover, despite the physiological and biomechanical significance of the chondrolabral junction (CLJ), the clinical implications of damage to this transition zone remain understudied.

PURPOSE

To (1) report minimum 8-year survivorship and patient-reported outcome measures after hip arthroscopy for FAI and (2) characterize associations between outcomes and patient characteristics (age, body mass index, sex), pathological parameters (Tönnis angle, alpha angle, type of FAI, CLJ breakdown), and procedures performed (labral management, FAI treatment, microfracture).

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This retrospective cohort study included patients who underwent primary hip arthroscopy for symptomatic labral tears secondary to FAI by a single surgeon between 2002 and 2013. All patients were ≥18 years of age with minimum 8-year follow-up and available preoperative radiographs. The primary outcome was conversion to total hip arthroplasty (THA), and secondary outcomes included revision arthroscopy, patient-reported outcome measures, and patient satisfaction. CLJ breakdown was assessed using the Beck classification. Kaplan-Meier estimates and weighted Cox regression were used to estimate 10-year survivorship (no conversion to THA) and identify risk factors associated with THA conversion.

RESULTS

In this study of 174 hips (50.6% female; mean age, 37.8 ± 11.2 years) with mean follow-up of 11.1 ± 2.5 years, the 10-year survivorship rate was 81.6% (95% CI, 75.9%-87.7%). Conversion to THA occurred at a mean 4.7 ± 3.8 years postoperatively. Unadjusted analyses revealed several variables significantly associated with THA conversion, including older age; higher body mass index; higher Tönnis grade; labral debridement; and advanced breakdown of the CLJ, labrum, or articular cartilage. Survivorship at 10 years was inferior in patients exhibiting severe (43.6%; 95% CI, 31.9%-59.7%) versus mild (97.9%; 95% CI, 95.1%-100%) breakdown of the CLJ (P < .001). Multivariable analysis identified worsening CLJ breakdown (weighted hazard ratio per 1-unit increase, 6.41; 95% CI, 3.11-13.24), older age (1.09; 95% CI, 1.04-1.14), and higher Tönnis grade (4.59; 95% CI, 2.13-9.90) as independent negative prognosticators (P < .001 for all).

CONCLUSION

Although most patients achieved favorable minimum 8-year outcomes, several pre- and intraoperative factors were associated with THA conversion; of these, worse CLJ breakdown, higher Tönnis grade, and older age were the strongest predictors.

Structure, composition and anisotropic swelling of the bovine acetabular labrum

The fibro-cartilaginous labrum surrounds the acetabular rim and is important for hip joint stability and sealing. Sealing may be enhanced by swelling pressure within the normal labrum. Swelling of the degenerated or torn labrum might occur and potentially contribute to the development of osteoarthritis, through altered load transmission. This study aimed to characterize the three-dimensional swelling behaviour, the collagen fiber orientation and spatial proteoglycan distribution of the bovine acetabular labrum. Specimens were harvested from bovine donors (192-652 days, male, n = 6 donors). Structure was analyzed by scanning electron microscopy, histology, and dimethylmethylene blue assay. Specimen dimensions were measured before and after incubation in phosphate buffered saline to assess the swelling. Results showed that the articulating surface is composed of a collagen mesh network. Collagen fiber bundles showed a low degree of alignment close to the surface and were circumferentially aligned in the deep tissue. Proteoglycans were identified clustered between the collagen bundles. Glycosaminoglycan content was 10 x lower than that of cartilage (23.1 ± 6.4 compared to 299.5 ± 19.1 μg/mg dry weight) with minor regional differences. Specimens swelled significantly more in the orthogonal direction (swelling ratio 124.7 ± 10.2%) compared to the swelling parallel to the articulating surface (108.8 ± 6.1% and 102.8 ± 4.1%). In the deep tissue, swelling was also restricted in the main collagen fiber bundle direction (circumferentially), with a swelling ratio of 109.5 ± 4.0% in the main fiber bundle direction compared to 126.8 ± 7.3 % and 122.3 ± 5.8% radially. The findings demonstrate that the labrum shows anisotropic swelling properties, which reflect the anisotropy in the tissue structure and inter-fiber localisation of proteoglycans.

Acetabular Labral Reconstruction Does Not Demonstrate Superior Biomechanical Properties Compared to Labral Repair or Intact Native Labrum but Is Superior to Labral Excision: A Systematic Review of Cadaveric Studies

PURPOSE

To systematically review and compare biomechanical properties of labral reconstruction to labral repair, intact native labrum, and labral excision in cadaveric studies.

METHODS

A search of the PubMed and Embase databases was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and checklist. Cadaveric studies focused on hip biomechanics related to intact labrum, labral repair, labral reconstruction, labral augmentation, and labral excision were included. Investigated parameters included biomechanical data measures, such as distraction force, distance to suction seal rupture, peak negative pressure, contact area, and fluid efflux. Review articles, duplicates, technique reports, case reports, opinion articles, articles written in a language other than English, clinical studies focusing on patient-reported outcomes, studies performed in animals, and articles with no abstract available were also excluded.

RESULTS

Fourteen cadaveric biomechanical studies were included that compared labral reconstruction to labral repair (4 studies), labral reconstruction to labral excision (4 studies); and evaluation of distractive force of the labrum (3 studies), the distance to suction seal rupture (3 studies), fluid dynamics (2 studies), displacement at peak force (1 study), and stability ratio (1 study). Data pooling was not performed because of methodological heterogenicity of the studies. Labral reconstruction did not outperform labral repair in restoring the hip suction seal or any other biomechanical property. Labral repair significantly prevented greater fluid efflux when compared to labral reconstruction. Labral repair and reconstruction improved the distractive stability of the hip fluid seal from the labral tear and labral excision stage, respectively. Furthermore, labral reconstruction demonstrated to have better biomechanical properties than labral excision.

CONCLUSIONS

In cadaveric studies, labral repair or intact native labrum was biomechanically more superior than labral reconstruction; however, labral reconstruction can restore acetabular labral biomechanical properties and was biomechanically superior to labral excision.

CLINICAL RELEVANCE

In cadaveric models, labral repair outperforms segmental labral reconstruction in preserving the hip suction seal; nonetheless, segmental labral reconstruction biomechanically outperforms labral excision at time 0.

Isolated Arthroscopic Debridement of Acetabular Labral Tears: High Rates of Failure and Conversion to Total Hip Arthroplasty at 13-Year Minimum Follow-up

BACKGROUND

Historically, symptomatic hip labral lesions were treated with arthroscopic debridement. Hip labral repair has become the standard treatment for labral pathology; however, to date, there are limited long-term studies regarding the outcomes of isolated labral debridement.

PURPOSE

To (1) evaluate the long-term patient-reported outcomes of isolated labral debridement, (2) report reoperation and arthroplasty rates, and (3) identify risk factors contributing to reoperation or poor clinical outcomes.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A retrospective review of a prospectively generated cohort of 59 hips in 57 patients from 1996 to 2010 who underwent hip arthroscopy with labral debridement was performed. Only patients with Tönnis grade <3 were included. Additionally, given the time period analyzed, resection of cam morphology was not performed, and the interportal capsulotomy was not repaired. The pre- and postoperative modified Harris Hip Score; Hip Outcome Score (HOS)-Activities of Daily Living and -Sports scores; and reoperation, conversion to total hip arthroplasty, and risk factors were analyzed.

RESULTS

In total, 48 hips in 47 patients (14 men, 33 women; mean age, 48.0 ± 12.9 years) met inclusion criteria and were followed for a mean of 17 ± 3 years (range, 13-27 years). The mean preoperative Tönnis grade was 1.3 ± 0.6 (range, 0-2), the mean chondral acetabular International Cartilage Regeneration & Joint Preservation Society (ICRS) grade was 1.7 ± 1.6 (range, 0-4), the mean chondral femoral ICRS grade was 0.9 ± 1.4, and the mean acetabular labral articular cartilage grade was 2.5 ± 1.2 (range, 0-4). At the final follow-up, mean the modified Harris Hip Score, HOS-Activities of Daily Living score, and HOS-Sports score were 82.2 ± 16.6, 81.9 ± 20.5, and 82.2 ± 20.5, respectively. Nineteen hips underwent subsequent reoperation at a mean of 5.5 ± 6.2 years (range, 0.5-21.2 years) postoperatively, including 16 hips (33% overall) being converted to total hip arthroplasty. Higher acetabular ICRS chondral grades at the time of surgery were observed in patients who went on to subsequent surgery compared with those who did not (2.3 ± 1.6 vs 1.1 ± 1.5; P = .02). In reoperation-free hips, Tönnis grade demonstrated a trend of increasing over time (1.4 preoperatively vs 1.7 at radiographic follow-up; P = .08). At the final follow-up, 19 hips (40%) had undergone reoperation, and 5 additional hips (10%) were rated as "abnormal" or "severely abnormal" in function, resulting in an overall clinical failure rate of 50%.

CONCLUSION

Isolated labral debridement was found to result in high rates of failure and reoperation, with a third of patients being converted to arthroplasty and half of patients meeting criteria for reoperation or clinical failure. Of note, for patients remaining reoperation-free, satisfactory outcome scores were observed.

Best practice guidelines for clinical and radiological assessment of patients with femoroacetabular impingement. Results from the ISHA International Delphi Consensus Project-Phase 2

In 2018, the International Society for Hip Preservation Surgery (ISHA) initiated a series of Delphi consensus studies to identify the global hip preservation community's current opinion on best practices for different facets of hip preservation surgery. Arthroscopic procedures to treat hip pathologies, such as femoroacetabular impingement syndrome (FAIS) are now established in mainstream orthopaedic practice. This study establishes recommendations for the investigation of patients with suspected FAIS. The investigation has focused on the three phases of the diagnostic process-patient history, physical examination and special investigations. Our expert panel consisted of 174 international orthopaedic surgeons with expertise in hip preservation surgery, thereby making recommendations generalisable across the globe. After three rounds of survey and analysis with 174 participants per round, our study achieved consensus at a minimum agreement threshold of 80.0% on 55 statements pertaining to the assessment of patients with FAIS. We encourage our junior and senior hip arthroscopy colleagues internationally to consider these statements both to standardize the clinical and radiological assessment of patients with FAIS and to aid in the design of future research.

Labral Reconstruction via Capsular Augmentation Maintains Perfusion to the Acetabular Labrum and Locally Transferred Autograft: An in Vivo Laser Doppler Flowmetry Analysis

Background

The purpose of the present study was to examine the effects of arthroscopic labral repair with capsular augmentation on blood flow in vivo with use of laser Doppler flowmetry (LDF) to measure microvascular perfusion of the labrum and autograft tissue.

Methods

The present prospective case series included patients ≥18 years old who underwent arthroscopic acetabular labral repair with capsular augmentation; all procedures were performed by a single surgeon between 2018 and 2022. The LDF probe measured microvascular blood flow flux within 1 mm3 of the surrounding labral and capsular tissue of interest. Mean baseline measurements of flux were compared with readings immediately following capsular elevation and after completing labral augmentation. Blood flux changes were expressed as the percent change from the baseline measurements.

Results

The present study included 41 patients (24 men [58.5%] and 17 women [41.5%]) with a mean age (and standard deviation) of 31.3 ± 8.4 years, a mean BMI of 24.6 ± 3.4 kg/m2, a mean lateral center-edge of angle 35.3° ± 4.9°, a mean Tönnis angle of 5.8° ± 5.8°, and a mean arterial pressure of 93.7 ± 10.9 mm Hg. Following capsular elevation, the mean percent change in capsular blood flow flux was significantly different from baseline (-9.24% [95% confidence interval (CI), -18.1% to -0.04%]; p < 0.001). Following labral augmentation, the mean percent change in labral blood flow flux was significantly different from baseline both medially (-22.3% [95% CI, -32.7% to -11.9%]; p < 0.001) and laterally (-32.5% [95% CI, -41.5% to -23.6%]; p = 0.041). There was no significant difference between the changes in medial and lateral perfusion following repair (p = 0.136).

Conclusions

Labral repair with capsular augmentation sustains a reduced blood flow to the native labrum and capsular tissue at the time of fixation. The biological importance of this reduction is unknown, but these findings may serve as a benchmark for other labral preservation techniques and support future correlations with clinical outcomes.

Level of Evidence

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Hip Joint Venting Decreases the Traction Force Required to Access the Central Compartment During Hip Arthroscopy

Purpose

To investigate the effect of hip joint venting on the magnitude of traction force required to arthroscopically access the central compartment of the hip.

Methods

Patients who underwent hip arthroscopy for femoroacetabular impingement syndrome prospectively underwent an intraoperative traction protocol. Joint space was measured on fluoroscopic images obtained at 50 and 100 lbs of axial traction in the prevented and vented state, and joint space values were normalized to millimetric values using preoperative anteroposterior pelvis radiographs. Venting was performed by inserting a large gauge spinal needle into the hip joint through the hip capsule and removing the stylet. Joint space differences were compared with paired t-tests, Wilcoxon signed-rank tests, and McNemar tests.

Results

Fifty hips in 46 patients were included. Mean joint space before venting was 7.4 ± 2.6 mm and 13.3 ± 2.8 mm at 50 and 100 lbs of traction, respectively. Mean joint space after venting was 13.9 ± 2.3 mm and 15.5 ± 2.4 mm at 50 and 100 lbs of traction, respectively. Mean differences in joint space at 50 and 100 lbs were 6.5 mm (P < .001) and 2.2 mm (P < .001), respectively. Mean joint space at 50 lbs in the vented state was significantly greater than in the pre-vented state at 100 lbs (13.9 mm vs. 13.3 mm; P = .002). The increase in joint space between 50 and 100 lbs of traction was significantly greater in the prevented state than in the vented state (5.9 mm vs 1.6 mm; P = .021).

Conclusions

Venting the hip reduces the traction force necessary to arthroscopically visualize and instrument the central compartment of the hip by at least 50%. Further, residual negative pressurization of the hip joint remains after breaking the labral suction seal and venting effectively eliminates this phenomenon to aid in hip joint distraction at lower traction force.

Level of Evidence

Level IV, case series.

Single Portal Segmental Labral Reconstruction of the Hip

Many techniques have been described for reconstruction of the acetabular labrum, but the procedure is known to be technically rigorous leading to lengthy procedure times and traction times. Increasing efficiency of the procedure with respect to graft preparation and delivery remain areas for potential improvement. We describe a simplified procedure for arthroscopic segmental labral reconstruction using peroneus longus allograft and a single working portal to shuttle the graft into the joint via suture anchors placed at the terminal extents of the graft defect. This method allows for efficient preparation, placement and fixation of the graft that can be completed in under 15 minutes.

Arthroscopic Repair of the Acetabular Labrum Using an Anchor-First Modified Toggle Suture Technique

The goal of acetabular labral repair is to restore stable contact between the labrum and acetabular rim while maintaining the anatomic suction seal. One of the challenges of labral repair is achieving proper in-round repair, so that the labrum contacts the femoral head in the native position. This technique article presents a repair method that allows for enhanced inversion of the labrum to assist with anatomic repair. Our modified toggle suture technique utilizes an anchor-first method and has various distinct technical advantages. We present an efficient and vendor-agnostic technique that allows for straight or curved guides. Similarly, the anchors may be all-suture or hard-anchor designs that accommodate suture sliding. This technique also utilizes a self-retaining hand-tied knot construct to facilitate preventing knots from migrating toward the femoral head or joint space.

Criteria-Based Rehabilitation Following Revision Hip Arthroscopy: A Clinical Commentary

Hip revision arthroscopy is becoming an increasingly popular surgery for those with unsatisfactory outcomes following primary hip arthroscopy. With the relatively uncommon but potentially increased difficulty of rehabilitation from this surgery, a lack of established research regarding rehabilitative programs remains. Therefore, the purpose of this clinical commentary is to propose a criterion-based progression that considers the intricacies present following a hip revision arthroscopy from early rehabilitation through return to sport. Criteria are presented clearly to promote objective progression through rehabilitation as opposed to relying on time since surgery as revision surgeries do not always follow traditional tissue healing time-frames. This criterion based progression promotes range of motion (ROM), strength, gait, neuromuscular control, load introduction and gradual return to play.

Level of Evidence

5.

Tissue Integration and Chondroprotective Potential of Acetabular Labral Augmentation with Autograft Tendon: Study of a Porcine Model

BACKGROUND

The aim of this study was to explore the tissue healing process and changes in articular cartilage following acetabular labral augmentation in a porcine model.

METHODS

The labrum was resected unilaterally from 10 o'clock to 1 o'clock on the capsular side in 36 pigs. Eighteen pigs underwent labral augmentation (AUG group) using autologous Achilles tendon. No additional procedures were performed in the remaining pigs (control group). The pigs were killed at 6, 12, or 24 weeks postoperatively for histological assessment and measurement of the inflammatory cytokines interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α in synovial fluid.

RESULTS

All autografts were well placed in the labral defect in the AUG group, and good integration of the autograft with the remnant chondrolabral junction was observed at 24 weeks; only scar tissue was observed in the control group at 6, 12, and 24 weeks. Fibrochondrocytes were concentrated at the transition between the autograft and native labrum at early time points, and the cells within the autograft labrum were predominantly fibrochondrocytes at 24 weeks. Rough and irregular articular cartilage surfaces were observed in 3 of the 6 samples in the AUG group at 24 weeks; the others appeared smooth. Focal cartilage erosion (predominantly in the acetabulum) occurred in all samples in the control group at 12 and 24 weeks. The Mankin score at 24 weeks was significantly lower in the AUG group than in the control group (mean [95% confidence interval]: 2.33 [1.06 to 3.6] versus 9 [8.06 to 9.94], p < 0.001). Likewise, the concentrations of all cytokines (in pg/mL) were significantly lower in the AUG group than in the control group at 24 weeks (IL-6: 166.6 [155.22 to 177.94] versus 245.9 [242.66 to 249.14], p < 0.001; IL-1β: 122.1 [116.4 to 127.83] versus 282.9 [280.29 to 285.51], p < 0.001; and TNF-α: 56.22 [53.15 to 59.29] versus 135 [131.66 to 138.24], p < 0.001).

CONCLUSIONS

Autograft tendon used for labral augmentation was able to integrate well with the native labrum, which may help to preserve the articular cartilage.

CLINICAL RELEVANCE

Labral augmentation with autograft tendon may be a feasible option in cases of viable labral remnants.

The acetabular labrum tissue shows unique transcriptome signatures compared to cartilage and responds to combined cyclic compression and surface shearing

The labrum is a fibrocartilaginous ring surrounding the acetabulum. Loss of labrum function contributes to the degeneration of the hip joint, leading to osteoarthritis. Successful labrum restoration requires profound knowledge about the tissue being replaced. The aim of this study was to characterize the transcriptome and the mechanobiological function of the labrum. RNA-seq was performed to compare the transcriptome of bovine labrum against articular cartilage tissue. Differential expression and gene ontology (GO) term pathway analysis were applied using the SUSHI framework. Bovine labrum explants were cultured for 5 days with / without mechanical loading and targeted gene expression was analyzed by real time quantitative polymerase chain reaction. More than 6'000 genes were significantly differentially expressed in the labrum compared to cartilage. Up- and downregulated genes were associated with the GO term extracellular matrix organization. The study established an extracellular matrix gene expression profile of healthy labrum tissue and identified significantly upregulated extracellular matrix related genes compared to cartilage tissue. Mechanical loading significantly upregulated aggrecan (ACAN), cartilage oligomeric matrix protein (COMP), fibronectin (FN1) and proteoglycan 4 (PRG4). MMP1/3/9 and IL6, which were upregulated by an inflammatory stimulus (IL-1b), were statistically unaffected by the loading, although IL6 was upregulated in each donor immediately after the loading. Unique ECM related features may guide the development of labrum tissue-engineering solutions. Despite the transcriptome differences between labrum and cartilage tissue, gene expression response to mechanical loading showed similarities with previously reported responses in cartilage, indicating a preserved tissue adaptation mechanism to mechanical loading. Running title: Acetabular Labrum Mechanobiology.

Calibration procedure and biomechanical validation of an universal six degree-of-freedom robotic system for hip joint testing

PURPOSE

Among various test methods for different human joints, the use of robot systems has attracted major interest and inherits the potential to become a gold standard in biomechanical testing in the future. A key issue associated with those robot-based platforms is the accurate definition of parameters, e.g., tool center point (TCP), length of tool or anatomical trajectories of movements. These must be precisely correlated to the physiological parameters of the examined joint and its corresponding bones. Exemplified for the human hip joint, we are creating an accurate calibration procedure for a universal testing platform by using a six degree-of-freedom (6 DOF) robot and optical tracking system for recognition of anatomical movements of the bone samples.

METHODS

A six degree-of-freedom robot (TX 200, Stäubli) has been installed and configured. The physiological range of motion of the hip joint composed of a femur and a hemipelvis was recorded with an optical 3D movement and deformation analysis system (ARAMIS, GOM GmbH). The recorded measurements were processed by automatic transformation procedure (created in Delphi software) and evaluated in 3D CAD system.

RESULTS

The physiological ranges of motion were reproduced for all degrees of freedom with the six degree-of-freedom robot in adequate accuracy. With the establishment of a special calibration procedure by using a combination of different coordinate systems, we were able to achieve a standard deviation of the TCP depending of the axis between 0.3 and 0.9 mm and for the length of tool between + 0.67 and - 0.40 mm (3D CAD processing) resp. + 0.72 mm to - 0.13 mm (Delphi transformation). The accuracy between the manual and robotic movement of the hip shows an average deviation between - 0.36 and + 3.44 mm for the points on the movement trajectories.

CONCLUSION

A six degree-of-freedom robot is appropriate to reproduce the physiological range of motion of the hip joint. The described calibration procedure is universal and can be used for hip joint biomechanical tests allowing to apply clinically relevant forces and investigate testing stability of reconstructive osteosynthesis implant/endoprosthetic fixations, regardless of the length of the femur, size of the femoral head and acetabulum or whether the entire pelvis or only the hemipelvis will be used.

Diagnostic value of magnetic resonance imaging and magnetic resonance arthrography for assessing acetabular labral tears: A systematic review and meta-analysis

BACKGROUND

This study aimed to systematically evaluate the value of magnetic resonance imaging (MRI) and magnetic resonance arthrography (MRA) in the diagnosis of acetabular labral tears.

METHODS

Databases including PubMed, Embase, Cochrane Library, Web of Science, CBM, CNKI, WanFang Data, and VIP were electronically searched to collect relevant studies on magnetic resonance in the diagnosis of acetabular labral tears from inception to September 1, 2021. Two reviewers independently screened the literature, extracted data, and assessed the risk of bias in the included studies by using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. RevMan 5.3, Meta Disc 1.4, and Stata SE 15.0 were used to investigate the diagnostic value of magnetic resonance in patients with acetabular labral tears.

RESULTS

A total of 29 articles were included, involving 1385 participants and 1367 hips. The results of the meta-analysis showed that the pooled sensitivity, pooled specificity, pooled positive likelihood ratio, pooled negative likelihood ratio, pooled diagnostic odds ratio, area under the curve of the summary receiver operating characteristic, and Q* of MRI for diagnosing acetabular labral tears were 0.77 (95% confidence interval [CI], 0.75-0.80), 0.74 (95% CI, 0.68-0.80), 2.19 (95% CI, 1.76-2.73), 0.48 (95% CI, 0.36-0.65), 4.86 (95% CI, 3.44-6.86), 0.75, and 0.69, respectively. The pooled sensitivity, pooled specificity, pooled positive likelihood ratio, pooled negative likelihood ratio, pooled diagnostic odds ratio, area under the curve of the summary receiver operating characteristic, and Q* of MRA for diagnosing acetabular labral tears were 0.87 (95% CI, 0.84-0.89), 0.64 (95% CI, 0.57-0.71), 2.23 (95% CI, 1.57-3.16), 0.21 (95% CI, 0.16-0.27), 10.47 (95% CI, 7.09-15.48), 0.89, and 0.82, respectively.

CONCLUSION

MRI has high diagnostic efficacy for acetabular labral tears, and MRA has even higher diagnostic efficacy. Due to the limited quality and quantity of the included studies, the above results should be further validated.

Tissue Regrowth and Its Vascularization Through Bone Marrow Stimulation: Microfracture at the Acetabular Rim for Irreparable Labral Tear in a Porcine Model

BACKGROUND

The treatment of irreparable acetabular labral tear remains a great challenge. Whether fibrocartilage-like tissue can regrow with sufficient volume to fill the labral defect area through bone marrow stimulation remains unknown.

PURPOSE

To characterize the healing process and vascularization course of the regrown tissue after microfracture at the acetabular rim for irreparable labral tears in a porcine model.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Twelve pigs randomly underwent unilateral microfracture at the acetabular rim after the resection of a 10 mm-long section of labrum from 10 to 1 o'clock. Pigs were randomly sacrificed at 6 and 12 weeks postoperatively. The regrown tissues were harvested for macroscopic evaluation and histologic assessment. The regrown tissue was zoned into 2 halves to observe the vascular distribution: the capsular half (zone I) and the articular half (zone II). Each zone was divided into 2 parts: the peripheral part (IA and IIA) and the part attached to the acetabulum (IB and IIB).

RESULTS

At 6 weeks, all regrown tissue was hypotrophic with <50% filling of the labral defect. Fibrochondrocytes were concentrated at the interface between the acetabulum and the regrown tissue. The vascularization was equal among each part within the regrown tissue. As compared with regrown tissue at 12 weeks, proteoglycan and collagen type 1 and 2 were more evident within the regrown tissue at 6 weeks. At 12 weeks, tissue disintegration occurred in all regrown tissue with <25% filling of the labral defect area. The vascular structure could barely be observed, with few fibrochondrocytes found at the area adjacent to the acetabulum.

CONCLUSION

Fibrocartilage-like tissue did regrow with well-distributed vascular ingrowth of each part of the regrown tissue through bone marrow stimulation at the early stage. However, insufficient volume of the regrown tissue led to loss of the hip suction seal and subsequent tissue disintegration.

CLINICAL RELEVANCE

Microfracture at the rim of the acetabulum alone could not restore the morphology and function of the acetabular labrum. Nonetheless, microfracture at the acetabular rim might be a viable adjunct to labral reconstruction, as the well-distributed vascularization through bone marrow stimulation might overcome the obstacle of poor vascular ingrowth of the articular half of the autograft.

The Cartilage Protective Effect of Labrum Reconstruction Using Meniscus Allograft Compared with Labrum Resection in a Porcine Model

PURPOSE

This study aimed to verify the femoral head cartilage protective effect of labral reconstruction in a porcine model.

METHODS

Twelve pigs (24 hips) were divided into 3 groups: labrum defect group, lateral meniscus (LM) allograft group, and LM allograft wrapped with acellular peritoneum matrix (LM-APM) group before undergoing bilateral hip surgery. The pigs were sacrificed at 12 and 24 weeks postoperatively, while the femoral head cartilage was retrieved and then subjected to imaging measurement, macroscopic observations, and biomechanical and histological assessment.

RESULTS

Imaging measurement and macroscopic observations revealed that the defect area of the labrum was filled in LM and LM-APM allograft groups after 24 weeks, whereas the labrum defect remained at 24 weeks in the control group. The femoral head cartilage corresponding to the area of labral resection in the labral defect group had worse macroscopic Osteoarthritis Research Society International (OARSI) scores, uneven and discontinuous cartilage on hematoxylin and eosin (H&E) staining and Safranin O staining, decreased histopathology OARSI Osteoarthritis Cartilage Histopathology Assessment System (OOCHAS) scores, and decreased elastic modulus and hardness at 12 and 24 weeks after surgery compared with the meniscus allograft groups.

CONCLUSION

This study demonstrated that the LM allograft with or without APM for labral reconstruction had a chondroprotective effect on the femoral head in a porcine model.

Changes in Hip Labral Size Two Years After Arthroscopic Repair Are Correlated With Preoperative Measurements on Magnetic Resonance Imaging

PURPOSE

The purposes of our study were 1) to investigate the potential change of labral size after arthroscopic repair and 2) to analyze the relationship between acetabular labral size and functional outcomes.

METHODS

In this retrospective study, patients diagnosed with labral tear and undergoing hip arthroscopic repair in our institution between September 2016 and December 2018 were included. Magnetic resonance imaging was obtained preoperatively and postoperatively, and the labral length and labral height were measured in three anatomic sites: 11:30, 1:30, and 3:00 positions. All patients completed at least 2-year follow-up. Patients whose preoperative labral size in any position wider than 2 standard deviation away from the mean were identified as the hypertrophic labrum group and were compared with the control in radiographic variables and patient-reported outcomes (PROs), including the visual analog scale (VAS), modified Harris Hip Score (mHHS), the International Hip Outcome Tool-12 (iHOT-12) and the Hip Outcome Score-Activities of Daily Living (HOS-ADL).

RESULTS

A total of 82 patients (82 hips) were included, and the mean follow-up period was 39.54 ± 8.48 months. Significant improvement in PROs was determined before and after surgeries. Twelve patients were identified with labral hypertrophy and had higher postoperative mHHS scores, higher postoperative iHOT-12 scores, and greater improvement in HOS-ADL compared with the control group. Patients with larger preoperative anterosuperior labral height exhibited more favorable clinical outcomes. Meanwhile, no significantly morphologic change in labral size was determined.

CONCLUSION

There is no significantly morphologic change in labral size of superior, anterosuperior, and anterior labrum after arthroscopic repair. Patients with hypertrophic labrum achieved more favorable clinical outcomes compared with those with normal-sized labrum.

LEVEL OF EVIDENCE

Level III, retrospective comparative prognostic trial.

Allograft reconstruction of acetabular labrum has comparable outcomes to labral refixation

The acetabular labrum plays an important role in hip stability, intra-articular fluid pressurization and force distribution. For irreparable labral pathology, labral reconstruction is an increasingly adopted technique shown to decrease hip pain and improve function. We evaluated survivorship and clinical outcomes of allograft labral reconstruction using the mini-open anterior surgical approach. Twelve patients who underwent labral reconstruction using a semitendinosus tendon allograft (reconstruction group) were matched 1:3 based on age, gender, body mass index, year of surgery, preoperative Tönnis grade, previous hip surgery, residual hip pathology and extent of acetabular chondral lesion to a control group of 36 patients who underwent direct labral repair with anchors (refixation group). At a minimum follow-up of 2 years, patient-reported outcomes, radiological findings and failure rates were compared. The average age was 31.3 years (±13.6) for reconstruction and 34.7 (±10.2) for refixation. Both groups had similar preoperative symptomatic periods (P = 0.3), prevalence of residual hip pathology (P = 1.0) and prevalence of prior hip surgeries (P = 1.0). both groups had a significant improvement of modified Harris Hip scores and 36-Item Short-Form Health Survey physical scores. There was no statistically significant difference in conversion rates to total hip arthroplasty (25% versus 8.3%, P = 0.2); however, time to conversion was significantly longer in the reconstruction group (3.58 years ±1.04) compared to the refixation group (1.20 years± 0.93; P = 0.04). In conclusion, at a minimum of 2 years of follow-up, mini-open labrum reconstruction for severe insufficiency of acetabular labrum demonstrated comparable improvements in functional outcomes and significantly longer survivorship compared to labral refixation.

Evaluation of the labrum on postoperative magnetic resonance images: a predictor of acetabular development in developmental dysplasia of the hip

INTRODUCTION

Residual acetabular dysplasia of the hip after open reduction can complicate the treatment of developmental dysplasia of the hip (DDH) due to the potential need for corrective surgery. This retrospective study aimed to determine the predictive factors for acetabular development using postoperative radiographs and magnetic resonance imaging (MRI).

METHODS

We retrospectively investigated 74 hips of patients with DDH who underwent open reduction after reaching walking age and were followed up radiologically until skeletal maturity. We evaluated the cartilaginous acetabulum and labrum using a new method that measures the cartilaginous and labral landmarks on coronal and axial MR T2*-weighted images in patients aged 5 years. The mean age at the time of surgery was 22 months and that at the final survey was 20 years. Severin classification was determined at the final follow-up. Groups with good (53 hips) and poor (21 hips) outcomes were compared using the postoperative radiographic and MRI parameters recorded at 5 years of age. Factors predicting acetabular development were identified using univariate and multiple logistic analyses.

RESULTS

There were no significant differences in the bony-acetabular index (AI) and centre-edge (CE) angle between the good and poor outcome groups. However, the poor outcome group had significantly larger cartilaginous- and labral-AIs but significantly smaller cartilaginous- and labral-CE angles than the good outcome group (both p < 0.05). Multiple logistic regression analysis showed that labral-AI and labral-CE angle were predictors of acetabular development after open reduction for DDH, and their optimal cut-offs were 4° (77% sensitivity, 76% specificity) and 37° (68% sensitivity, 85% specificity), respectively.

DISCUSSION

Normal cartilaginous acetabulum development occurs in childhood, and evaluation using only radiographs is difficult. However, labral-AI ⩾4° and labral-CE angle <37° on MRI at 5 years of age offer useful indications for corrective surgery in patients with DDH.

Hip Labral Reconstruction With a Polyurethane Scaffold: Restoration of Femoroacetabular Contact Biomechanics

Background:

Many advances have been made in hip labral repair and reconstruction and in the restoration of the suction seal.

Purpose/Hypothesis:

The purpose of this study was to evaluate the biomechanical effects of segmental labral reconstruction with a synthetic polyurethane scaffold (PS) in comparison with segmental labrectomy. Our hypothesis was that reconstruction with a icroporous polyurethane implant would normalize joint kinetics of the hip and restore the suction seal.

Study Design:

Controlled laboratory study.

Methods:

We used 10 hips from 5 fresh-frozen pelvises with an intact acetabular labrum without osteoarthritis. Using an intra-articular pressure measurement system, the contact area, contact pressure, and peak force were assessed for the following conditions: intact labrum, partial anterosuperior labrectomy, and PS reconstruction. For each condition, all specimens were analyzed in 4 positions (90° of flexion, 90° of flexion and internal rotation, 90° of flexion and external rotation, and 20° of extension) and underwent a labral seal test. The relative change from the intact condition was determined for all conditions and positions.

Results:

Compared with the intact labrum, labrectomy resulted in a significant decrease in the contact area (P < .001) and a significant increase in the peak force (P < .001) and contact pressure (P < .001) across all positions. Compared with labrectomy, PS reconstruction resulted in a significant increase in the contact area (P < .001) and a significant decrease in the contact pressure (P ≤ .02) and peak force (P < .001) across all positions. Compared with the intact labrum, PS reconstruction restored the contact area and peak force to normal values in all positions (P > .05), whereas the contact pressure was significantly decreased compared with labrectomy (P < .05) but did not return to normal values. The labral seal was lost in all specimens after labrectomy but was restored in 80% of the specimens after PS reconstruction.

Conclusion:

Femoroacetabular contact biomechanics significantly worsened after partial labrectomy; reconstruction using a PS restored the contact area and peak force to the intact state and improved the contact pressure increases seen after partial labrectomy. The contact area and peak force were normalized, and the labral seal was re-established in most cases.

Clinical Relevance:

This study provides biomechanical evidence for the use of a scaffold for labral reconstruction.

The Vascularization Course of Labral Autograft and Its Effect on Tissue Healing: Acetabular Labral Augmentation Versus Labral Reconstruction in a Porcine Model

BACKGROUND

The preservation of the native labral vascularization is assumed to be the potential advantage of acetabular labral augmentation, the effect of which remains unknown.

PURPOSE

To identify the vascular distribution within the labral autograft and its effect on the healing process between labral augmentation (AUG) and reconstruction (RECON) in a porcine model.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 36 pigs randomly underwent unilateral labral augmentation or reconstruction (AUG group, n = 18; RECON group, n = 18). The pigs were randomly sacrificed at 6, 12, and 24 weeks postoperatively. The labral autografts were harvested for macroscopic evaluation and histologic assessment. The labral autograft was zoned into 2 halves to observe the vascular distribution: the capsular half (zone I) and the articular half (zone II). Each zone was divided into 2 parts: the peripheral part (IA and IIA) and the part attached to the acetabulum (IB and IIB).

RESULTS

At 6 weeks, there existed more vascular ingrowth in zone I, whereas zone IIB appeared nearly avascular in both groups. At 12 weeks, the area with the greatest vascularity was zone II in the RECON group and zone IA in the AUG group. The vascularity was concentrated at zones IA and IIA in both groups at 24 weeks. The labral autografts were hypertrophic with sufficient filling of the labral defect in both groups at 6 weeks. At 12 weeks, an insufficient volume of the articular half was observed in 3 of 6 labral autografts in the RECON group, while all autografts remained well integrated with the chondrolabral junction in the AUG group. At 24 weeks, unsatisfactory merging of the labral autograft with the cartilage at the articular side was found in 2 of 6 labral autografts in the RECON group, which was not observed in the AUG group despite the sufficient volume of autografts labrum in both groups.

CONCLUSION

Slow vascular ingrowth within the articular half might account for the poor healing of the reconstructed labral autograft. Labral augmentation provides the possibility of better tissue healing because of the preservation of the original chondrolabral junction compared with labral reconstruction.

CLINICAL RELEVANCE

Labral augmentation might be a feasible alternative to labral reconstruction under the condition of viable labral remnants.

Arthroscopic Acetabular Labral Repair Versus Labral Debridement: Long-term Survivorship and Functional Outcomes

Background:

Arthroscopic treatment for labral tears includes debridement and repair. Long-term studies have failed to demonstrate a difference between these treatments in terms of conversion to total hip arthroplasty (THA).

Purpose:

To investigate 2 different labral treatments, debridement and repair, using an adjusted analysis to evaluate long-term conversion to THA.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

This was a retrospective cohort study of patients who underwent hip arthroscopy by a single surgeon between April 2007 and October 2014. Postoperative follow-up information included conversion to THA, patient satisfaction, and patient-reported outcome measures (modified Harris Hip Score; Hip Outcome Score, Activities of Daily Living and Sports Specific subscales; International Hip Outcome Tool; Nonarthritic Hip Score; and Lower Extremity Functional Scale).

Results:

Of the 204 hips included in the study, 99 (48.5%) underwent labral repair, and 105 (51.5%) underwent debridement. In total, 28 (13.7%) of the 204 patients underwent conversion to THA within 10 years after hip arthroscopy (labral repair: 5 [5.0%] vs labral debridement: 23 [21.9%]). Labral repair was associated with a significantly lower risk of conversion to THA compared with debridement (hazard ratio [HR] = 0.24; 95% CI, 0.07-0.74; P = .014). Additional factors associated with risk of conversion to THA included older age at the time of arthroscopy (HR = 1.06 per year; 95% CI, 1.02-1.11; P = .002) and Tönnis grade (HR = 2.39; CI, 1.14-5.41; P = .026). Abrasion chondroplasty, acetabuloplasty, body mass index, Outerbridge grade, and radiographic femoroacetabular impingement were not found to be significantly associated with risk of THA. No significant difference in patient satisfaction was found between treatment groups, and for patients who did not convert to THA, there was no difference in mean patient-reported outcome scores at final follow-up.

Conclusion:

Patients who underwent labral repair were less likely to convert to THA compared with patients who underwent labral debridement, despite adjustment for differences in baseline patient characteristics and preexisting pathology. Additional factors associated with a lower rate of hip survival were older age and osteoarthritis at the time of hip arthroscopy.

An Increased Allograft Width for Circumferential Labral Reconstruction Better Restores Distractive Stability of the Hip: A Cadaveric Biomechanical Analysis

BACKGROUND

Questions remain about whether circumferential labral reconstruction (CLR) using an iliotibial band (ITB) allograft can effectively restore the labral suction seal of the hip.

HYPOTHESES

(1) CLR with an ITB allograft >6.5 mm would restore distractive stability force to that of the intact labrum. (2) CLR with an ITB allograft >6.5 mm would achieve significantly superior distractive stability force compared with CLR with an ITB allograft <6.5 mm.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 6 fresh-frozen pelves with attached femurs (n = 12 matched hemipelves) from male donors were procured and dissected free of all soft tissue, including the hip capsule but preserving the native labrum, transverse acetabular ligament, and ligamentum teres. Potted hemipelves were placed in a saline bath and securely fixed to the frame of a hydraulic testing system. A 500-N compressive load was applied, followed by femoral distraction at a rate of 5.0 mm/s until the suction seal ruptured. Force and femoral displacement were continually recorded. Force versus displacement curves were plotted, the maximum force was recorded, and the amount of femoral distraction to rupture the suction seal was determined. After intact testing, the labrum was excised, and specimens were retested using the same protocol. CLR was subsequently performed twice in a randomized fashion using (1) an ITB allograft with a width >6.5 mm (7.5-9.0 mm) and (2) an ITB allograft with a width <6.5 mm (4.5-6.0 mm). Specimens were retested after each CLR procedure. Force (in Newtons) and femoral distraction (in millimeters) required to rupture the suction seal were measured and compared between the 4 testing states (intact, deficient, CLR <6.5 mm, and CLR >6.5 mm) using repeated-measures analysis of variance.

RESULTS

On average, intact specimens required 148.4 ± 33.1 N of force to rupture the hip suction seal, which significantly decreased to 44.3 N in the deficient state (P < .001). CLR with ITB allografts <6.5 mm did not improve the maximum force (63 ± 62 N) from the deficient state (P = .42) and remained significantly lower than the intact state (P < .01). CLR with ITB allografts >6.5 mm recorded significantly greater force to rupture the suction seal (135.8 ± 44.6 N) compared with both the deficient and CLR <6.5 mm states (P < .01), with a mean force comparable with the intact labrum (P = .59). The amount of femoral distraction to rupture the suction seal demonstrated similar findings.

CONCLUSION

In a cadaveric model, CLR using ITB allografts >6.5 mm restored the distractive force and distance to the suction seal rupture to values comparable with hips with an intact labrum. CLR using ITB allografts >6.5 mm outperformed CLR with ITB allografts <6.5 mm, demonstrated by a significantly higher force to rupture the suction seal and increased distraction before the rupture.

CLINICAL RELEVANCE

The results of this cadaveric investigation suggest that using wider labral allografts during CLR will provide the distractive force required to rupture the suction seal and immediate postoperative stability of the hip, although further studies are required to determine if these results translate to improved clinical outcomes.

Comparison of early outcomes of arthroscopic labral repair or debridement

Aims

This study uses prospective registry data to compare early patient outcomes following arthroscopic repair or debridement of the acetabular labrum.

Methods

Data on adult patients who underwent arthroscopic labral debridement or repair between 1 January 2012 and 31 July 2019 were extracted from the UK Non-Arthroplasty Hip Registry. Patients who underwent microfracture, osteophyte excision, or a concurrent extra-articular procedure were excluded. The EuroQol five-dimension (EQ-5D) and International Hip Outcome Tool 12 (iHOT-12) questionnaires were collected preoperatively and at six and 12 months post-operatively. Due to concerns over differential questionnaire non-response between the two groups, a combination of random sampling, propensity score matching, and pooled multivariable linear regression models were employed to compare iHOT-12 improvement.

Results

A total of 2,025 labral debridements (55%) and 1,659 labral repairs (45%) were identified. Both groups saw significant (p < 0.001) EQ-5D and iHOT-12 gain compared to preoperative scores at 12 months (iHOT-12 improvement: labral repair = +28.7 (95% confidence interval (CI) 26.4 to 30.9), labral debridement = +24.7 (95% CI 22.5 to 27.0)), however there was no significant difference between procedures after multivariable modelling. Overall, 66% of cases achieved the minimum clinically important difference (MCID) and 48% achieved substantial clinical benefit at 12 months.

Conclusion

Both labral procedures were successful in significantly improving early functional outcome following hip arthroscopy, regardless of age or sex. Labral repair was associated with superior outcomes in univariable analysis, however there was no significant superiority demonstrated in the multivariable model. Level of evidence: III Cite this article: Bone Jt Open 2022;3(4):291–301.

Midterm Outcomes After Hip Labral Augmentation in Revision Hip Arthroscopy

BACKGROUND

Labral augmentation has emerged as an essential procedure to address a deficient or irreparable labrum while preserving native labral tissue and restoring the hip suction seal mechanism.

PURPOSE

To evaluate midterm outcomes of arthroscopic hip labral augmentation for labral insufficiency after previous hip arthroscopy.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Patients were identified from a prospectively collected database who underwent arthroscopic hip labral augmentation between January 2011 and January 2017 with a minimum 3-year follow-up. Pre- and postoperative patient-reported outcome scores were compared and included the 12-Item Short Form Health Survey physical and mental component summaries, Western Ontario and McMaster Universities Osteoarthritis Index, modified Harris Hip Score (mHHS), and Hip Outcome Score (HOS) (Activities of Daily Living [ADL] and Sport). Postoperative Tegner Activity Scale and patient satisfaction (1-10) scores were also evaluated. The minimal clinically important difference (MCID) and Patient Acceptable Symptom State (PASS) between the preoperative and minimum 3-year follow-up scores were calculated.

RESULTS

A total of 88 patients (39 men, 49 women) underwent revision hip arthroscopy with labral augmentation. The average age was 32.8 ± 11 years. Of these, 77 patients (88%) were available for the minimum 3-year follow-up. The survivorship (absence of conversion to total hip arthroplasty) at 3 years and 5 years was 93% at both time points, with a mean survival time of 8.5 years (95% CI, 8.0-8.9). Eleven patients (14%) required revision arthroscopic surgery for continued pain. Revisions occurred at a mean of 2.6 ± 1.4 years after augmentation. The mean follow-up was 5.2 ± 1.2 years (range, 3-9 years). For patients not requiring subsequent surgery (n = 61), all patient-reported outcome measures significantly improved, which included a 20-point increase in HOS-ADL (MCID, 82%; PASS, 72%) and mHHS (MCID, 78%; PASS, 70%). The median postoperative Tegner score was 4 (range, 1-10). The median postoperative patient satisfaction score was 9 out of 10 (range, 1-10).

CONCLUSION

Arthroscopic hip labral augmentation is a successful treatment option for patients with labral insufficiency after previous hip arthroscopy, demonstrating improved patient-reported outcomes and survivorship of 93% at 3 years and 5 years. This technique provides a valuable labral preservation option when addressing hip labral pathology when viable native labral tissue remains.

Does labral treatment technique influence the outcome of FAI surgery? A matched-pair study of labral reconstruction versus repair and debridement with a follow-up of 10 years

The aim of this study was to analyze the long-term clinical outcomes of labral reconstruction in patients undergoing femoro-acetabular impingement (FAI) surgery and compare them with labral repair and debridement. This is a single-center, single-surgeon, retrospective match-paired study from a prospectively collected hip preservation database. All patients underwent a hip surgical dislocation for FAI surgery. Eight patients underwent labral reconstruction with the ligamentum teres and were matched on sex, age and body mass index with 24 labral repair and 24 labral debridement (1:3). Failure was defined as conversion to total hip replacement (THR) and patient-reported outcome measures (PROMs) were collected. Mean follow-up was 9.8 years ±2.6 (5.2–13.9). There was a significant improvement in postoperative PROMs in the three groups regarding the WOMAC total, WOMAC function, HOOS-QoL, HOOS-ADL and HOOS-SRA (P < 0.05). There was no statistical difference between the three groups regarding postoperative PROMs and change in PROMs (P > 0.05). A total of 10 hips underwent joint replacement surgery at a mean time of 7.9 ± 3.5 years (2.4–12). There was no statistically significant difference between the three groups regarding the conversion rate to THR (P = 0.64) or time between surgery and conversion to THR (P = 0.15). Compared to a match-pair group of labral repair and debridement, labral reconstruction with ligamentum teres provides similar survival with conversion to a THR as an endpoint, as well as similar improvement in PROMs. Labral treatment can be safely adapted at the nature of the labral lesion with a treatment ‘à la carte’.

The Short-term Outcomes of Physiotherapy for Patients with Acetabular Labral Tears: An Analysis according to Severity of Injury in Magnetic Resonance Imaging

Purpose

The aim of this study was to evaluate the short-term outcome of physiotherapy in patients with acetabular labral tears and to assess the effectiveness of physiotherapy according to the severity of the labral tear.

Materials and Methods

Thirty-five patients who underwent physiotherapy for treatment of symptomatic acetabular labral tears were enrolled. We evaluated the severity of the acetabular labral tears, which were classified based on the Czerny classification system using 3-T MRI. Clinical findings of microinstability and extra-articular pathologies of the hip joint were also examined. The International Hip Outcome Tool 12 (iHOT12) was use for evaluation of outcome scores pre- and post-intervention.

Results

The mean iHOT12 score showed significant improvement from 44.0 to 73.6 in 4.7 months. Compared with pre-intervention scores, significantly higher post-intervention iHOT12 scores were observed for Czerny stages I and II tears (all P<0.01). However, no significant difference was observed between pre-intervention and post-intervention iHOT12 scores for stage III tears (P=0.061). In addition, seven patients (20.0%) had positive microinstability findings and 22 patients (62.9%) had findings of extra-articular pathologies. Of the 35 patients, eight patients (22.9%) underwent surgical treatment after failure of conservative management; four of these patients had Czerny stage III tears.

Conclusion

The iHOT12 score of patients with acetabular labral tears was significantly improved by physiotherapy in the short-term period. Improvement of the clinical score by physiotherapy may be poor in patients with severe acetabular labral tears. Determining the severity of acetabular labral tears can be useful in determining treatment strategies.

Arthroscopic Debridement Versus Refixation of the Acetabular Labrum Associated With Femoroacetabular Impingement: Updated Mean 7-Year Follow-up

BACKGROUND

Short- and midterm follow-up studies suggest that arthroscopic labral refixation/preservation leads to superior outcomes compared with labral excision/debridement.

PURPOSE

To update the previous early (16 months) and midterm (mean, 42 months) follow-up of this cohort, which reported better patient-reported outcome measures and lower failure rates in the repair/refixation group.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

The authors identified patients who underwent labral debridement/focal labral excision during a period before the development of labral repair techniques. A consecutive group of patients within the labral debridement group thought to be repairable with the authors' current arthroscopic techniques were compared with a group of consecutive patients who underwent labral repair/refixation. In 46 hips, the labrum was focally excised/debrided consistent with pincer- or combined pincer- and cam-type impingement; in 54 hips, the labrum was repaired/refixed. Subjective outcomes were measured with the modified Harris Hip Score (mHHS), 12-Item Short Form Health Survey (SF-12), and visual analog scale (VAS) for pain preoperatively and postoperatively.

RESULTS

The mean age was 34.0 years in the debridement group and 28.3 years in the repair/refixation group, with a mean follow-up of 7.3 years (range, 2-13.6 years). At the mean follow-up of 7.3 years, subjective outcomes were significantly improved (P < .01) for both groups compared with preoperative scores. The mHHS (P = .008), SF-12 score (P = .012), and VAS pain score (P = .002) were all significantly better for the repair/refixation group compared with the debridement group. Although most recent outcomes for both groups fell slightly at the mean follow-up of 7.3 years in comparison with the 16-month and 3.5-year follow-ups, these differences were not significant. However, the failure rate in the debridement group did get significantly worse (P = .014). Good to excellent results were 47.7% in the debridement group and 86.3% in the refixation group (P < .001), and failure rates were 30.4% (debridement) and 13% (refixation) (P = .033). There were 4 revisions in the debridement group and 3 revisions in the refixation group.

CONCLUSION

Longer term, >7-year follow-up comparing focal labral excision/debridement with repair/refixation revealed better patient-reported outcomes and lower failure rates in the labral repair/refixation cohort. Additionally, despite an absolute decrease in patient-related outcome scoring and number of good/excellent results in both groups compared with the 3.5-year report, there was a significantly greater increase in failure rates over time for the excision/debridement group with better maintenance of good to excellent results in the repair/refixation group.

Arthroscopic acetabular labrum suture

It is essential to be aware of the anatomy and biomechanics of the acetabular labrum in order to understand why it should be conserved. Vascularization comes from the capsule and also from the bone. The joint side contains numerous nerve endings, which explains why labral lesions are painful. It is involved in joint stabilization by maintaining a negative pressure inside the joint able to resist distraction. It acts as a seal. There are two main suture techniques: trans- and peri-labral. Translabral suture is better suited to a wide and solid labrum free of degenerative lesions. Both techniques should be known, and may be associated. Results are comparable. It is essential to manage the underlying pathology responsible for the labral lesion. Joint degeneration is associated with poor prognosis. It needs to be recognized and discussed with the patient, to avoid unrealistic expectations.

Multicenter Outcomes After Primary Hip Arthroscopy: A Comparative Analysis of Two-Year Outcomes After Labral Repair, Segmental Labral Reconstruction, or Circumferential Labral Reconstruction

PURPOSE

(1) To report minimum 2-year follow-up patient-reported outcome measures in patients undergoing labral repair (LR), segmental labral reconstruction (SLR), or circumferential labral reconstruction (CLR) in the primary setting; and (2) to compare minimum 2-year follow-up patient-reported outcome measures among these groups.

METHODS

A retrospective review of a prospectively maintained multicenter database of patients undergoing hip arthroscopy was performed. Inclusion criteria were patients undergoing hip arthroscopy for treatment of labral tear and femoroacetabular impingement syndrome between January 2014 and October 2017, and completion of minimum 2-year postoperative outcome scores. Exclusion criteria were patients undergoing revision hip surgery, labral treatment limited to debridement, lateral center-edge angle <20°, osteoarthritis (Tönnis grade > 1), slipped capital femoral epiphysis, workers compensation status, and patients undergoing concomitant gluteus medius and/or minimus repair. Labral reconstruction patients were matched (1:3) with labral repair patients on age, sex, and body mass index. The labral reconstruction group was further stratified into SLR, and CLR groups. Patient demographic characteristics and clinical outcomes including Hip Outcome Score - Activities of Daily Living, Hip Outcome Score - Sport Subscale, modified Harris Hip Score, international Hip Outcome Tool, and visual analog scale for pain were analyzed, as well as achievement of the minimal clinical improvement difference (MCID). A P-value less than .05 indicated statistical significance.

RESULTS

A total of 416 patients were included (LR, n = 312; SLR, n = 53; CLR, n = 51). The age, body mass index, and sex of the matched cohort were 42.3 ± 11.2 years, 24.7 ± 3.7, and 55.0% female. At a minimum of 2-year after hip arthroscopic surgery, no differences were found in preoperative, postoperative, or the delta visual analog scale for pain, modified Harris Hip Score, Hip Outcome Score - Activities of Daily Living, Hip Outcome Score - Sport Subscale, or international Hip Outcome Tool. Subsequently, the proportion of patients achieving the MCID and the PASS at latest follow-up were analyzed. This analysis revealed that no significant differences in the rate of MCID or PASS achievement for any outcome measure existed based on labral treatment.

CONCLUSIONS

In this multicenter study on labral treatment in the primary setting, patients undergoing LR, SLR, and CLR demonstrated no difference in preoperative or postoperative scores, nor the proportion of patients achieving clinically significant outcome improvement.

LEVEL OF EVIDENCE

III; therapeutic outcome study with controls.

The Effect of Rim Preparation, Labral Augmentation, and Labral Reconstruction on the Suction Seal of the Hip

PURPOSE

To evaluate the biomechanical properties of the labral suction seal in the native labrum and after rim preparation, labral augmentation, and labral reconstruction.

METHODS

Eight hemi-pelvises were dissected to the level of labrum and mounted for biomechanical testing. Each specimen was tested in axial distraction starting with the native labrum and then sequentially following rim preparation from 12 to 3 o'clock, labral augmentation, and segmental labral reconstruction using the iliotibial band allograft. In each condition, the specimens were compressed to 250 N and then distracted at 10 mm/s with force and displacement continuously recorded. Each test was repeated 3 times, and the mean peak force, displacement at peak force, and work were calculated. Data were reported as a percentage of the intact values to account for sex and size differences. Statistical testing was performed via a repeated-measures analysis of variance with a post hoc Tukey analysis.

RESULTS

Peak loads occurred within 2.21 to 3.11 mm of displacement. The mean peak force, displacement at peak force, and work relative to the intact condition were the following: rim preparation (91.1% ± 8.5%, 94.4% ± 14.3%, 93.4% ± 23.5%, respectively), augmentation (66.1% ± 27.6%, 78.2% ± 16.3%, 55.7% ± 30.7%, respectively), and reconstruction (55.6% ± 25.7%, 64.7% ± 31.4%, 38.7% ± 27.2%, respectively). There was no significant difference in peak force following the rim preparation (P = .807), but peak force was significantly decreased after augmentation and reconstruction (P = .010 and P < .001, respectively). There was no significant difference in displacement at peak force following rim preparation or augmentation (P = .936 and P = .125, respectively), but displacement at peak force was significantly decreased after reconstruction (P = .005). The work from the suction seal was significantly less in both augmentation and reconstruction states compared to the intact labrum (P = .004 and P < .001, respectively) and rim preparation (P = .017 and P < .001, respectively).

CONCLUSIONS

The results show that the suction seal is not significantly changed following rim preparation. Relative to the rim preparation, labral augmentation may re-create the labral suction seal better than labral reconstruction.

CLINICAL RELEVANCE

This study provides a biomechanical basis for surgical decision making and clinical management of patients with labral tears of the hip.

Isolated Acetabuloplasty for Femoroacetabular Impingement: Favorable Patient-Reported Outcomes and Sustained Survivorship at Minimum 5-Year Follow-Up

PURPOSE

To evaluate minimum 5-year outcomes and conversion rate to total hip arthroplasty (THA) for the treatment of femoroacetabular impingement (FAI) syndrome with an isolated acetabular osteoplasty.

METHODS

Patients undergoing hip arthroscopy with an isolated acetabular osteoplasty from March 2009 to June 2014 for FAI syndrome with pincer and/or cam morphology and a labral tear were identified. Those who underwent femoroplasty or prior ipsilateral hip surgery or who had previous hip conditions, ipsilateral hip dysplasia, or a Tönnis grade higher than 2 were excluded. Patient-reported outcomes (PROs) collected included Patient-Reported Outcomes Measurement Information System (PROMIS) scores specific to physical functioning and pain interference, modified Harris Hip Score, International Hip Outcome Tool 12, Hip Outcome Score-Activities of Daily Living, Hip Outcome Score-Sport-Specific Subscale, and Numeric Pain Rating Scale. Patients were also queried about secondary surgical procedures and conversion to THA.

RESULTS

We identified 86 patients at minimum 5-year follow-up (average, 7.4 years). The average patient age was 39.8 ± 12.3 years, 70.9% of patients were female, and 7% of patients had Tönnis grade 2. The mean PRO scores were 52.0 ± 8.9 for the PROMIS physical functioning score, 39.6 ± 7.5 for the PROMIS pain interference score, 78.7 ± 12.0 for the modified Harris Hip Score, 73.3 ± 23.1 for the International Hip Outcome Tool 12 score, 89.9 ± 12.0 for the Hip Outcome Score-Activities of Daily Living, and 81.4 ± 21.0 for the Hip Outcome Score-Sport-Specific Subscale. Of the patients, 72.1% achieved the patient acceptable symptomatic state (PASS) according to previously established PASS scores for FAI syndrome treated with hip arthroscopy at minimum 5-year follow-up. The overall rate of revision arthroscopy was 3.5%, and the rate of conversion to THA was 5.8%.

CONCLUSIONS

An isolated acetabular osteoplasty can provide sustained clinical benefits for the treatment of FAI syndrome with labral tears, with good to excellent PROs and PASS rates and a low rate of conversion to THA at minimum 5-year follow-up.

LEVEL OF EVIDENCE

Level IV, case series.

Autograft Versus Allograft: The Evidence in Hip Labral Reconstruction and Augmentation

BACKGROUND

Labral augmentation and labral reconstruction have emerged as essential procedures for restoring the anatomic and functional characteristics of the hip joint in patients with a deficient hip labrum or irreparable labral tear.

HYPOTHESIS/PURPOSE

The purpose of this study was to compare allograft and autograft hip labral reconstruction and augmentation. We hypothesized that autografts would entail fewer revision arthroscopic procedures.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients were identified who underwent labral reconstruction or labral augmentation using iliotibial band (ITB) allograft or ITB autograft performed by a single surgeon between 2011 and 2017. Patient-reported outcome measures collected before surgery and at minimum 2-year follow-up included the following: Hip Outcome Score Activities of Daily Living and Hip Outcome Score Sports-Specific Subscale and, at follow-up, patient satisfaction (range, 1-10, with 10 being very satisfied). Patients followed a standardized rehabilitation protocol after surgery with relative individualization to address each patient's needs. For continuous variables, comparisons between allografts and autografts were made using Student t tests or Mann-Whitney tests. Categorical comparisons were assessed using chi-square or Fisher exact test. Multiple logistic regression was performed to determine the influence of graft choice on risk of revision or THA.

RESULTS

A total of 205 hips met 2-year inclusion criteria. ITB allografts were used for 55 patients (37 augmentations, 18 reconstructions) and ITB autografts for 150 patients (34 augmentations, 116 reconstructions). Females represented a greater proportion of allograft versus autograft patients (71% vs 46%, respectively; P = .001). Overall, autograft patients had larger alpha angles (66.6° vs 59.1°; P = .001) and longer grafts (46 vs 41 mm; P = .03) compared with allograft patients. A total of 13 (23.6%) patients required revision surgery in the allograft group compared with 11 (7.3%) in the autograft group (P < .001). After controlling for sex, procedure (reconstruction vs augmentation), and previous surgery, the odds of revision were higher for allograft patients (OR, 4.1; 95% CI, 1.5-11.6). No significant differences in conversion to THA were observed between groups (allograft = 9%; autograft = 6%; P = .50), even after adjustment for the above covariates (OR, 2.3; 95% CI, 0.6-7.9). No differences in postoperative patient-reported outcome measures or patient satisfaction were observed between groups.

CONCLUSION

Labral augmentation or reconstruction with autograft has a significantly lower revision rate than labral augmentation or reconstruction with allograft.

Acetabular labral tears in the adolescent athlete: results of a graduated management protocol from therapy to arthroscopy

This study sought to determine outcomes of a graduated management protocol from therapy to arthroscopy for adolescents presenting with hip pain and an associated acetabular tear. Thirty-seven hips with an MRI confirmed labral tear were prospectively enrolled in a graduated management protocol created for adolescents. The protocol began with activity modification and focused physical therapy. Patients with persistent symptoms were offered an intraarticular corticosteroid injection. Those with continued symptoms were treated with arthroscopic surgery. The modified Harris hip score (mHHS) and nonarthritic hip score (NAHS) were recorded at the initial visit. Patients were contacted by telephone at 1, 2, and 5 years from enrollment for repeat assessment with mHHS and NAHS. At presentation, the mean mHHS and NAHS for the entire cohort was 66.4  ±  11.4 and 70.2  ±  12.6, and these values improved significantly to 89.3  ±  10.6 and 87.0  ±  11.4 at a mean follow-up of 35.7  ±  18.3 months (range 11.7-64.4 months). Forty-two percent of hips were managed with physical therapy and activity modifications alone, 28% of hips progressed to a steroid injection but did not require surgery, and 31% required arthroscopic intervention. Seventy-three percent of hips treated with activity modification alone, 80% treated with an injection, and 82% of hips treated with arthroscopic repair met the minimal clinically significant difference (MCID) (P = 0.859). At an average of 36 months follow-up, the majority (78%) of adolescent patients with an acetabular labral tear will achieve the MCID utilizing a graduated management protocol.

Repair versus Debridement for Acetabular Labral Tears-A Systematic Review

Purpose

The purpose of this study was to systematically review the evidence in the literature to ascertain whether acetabular labral repair (ALR) or debridement (ALD) resulted in superior patient outcomes.

Methods

The systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Peer-reviewed studies comparing ALR and ALD published in English with full text available were included. Patients undergoing both open and arthroscopic surgery in randomized controlled trials, prospective cohort studies, retrospective cohort studies, and case-control studies were included. Studies were quantified for methodological quality using the MINORS criteria. Clinical outcomes were compared, with qualitative analysis, and quantitative analyses were performed using GraphPad Prism version 7. A P value <.05 was considered to be statistically significant.

Results

There were 8 studies included (level of evidence [LOE] I = 1; LOE II = 2; LOE III = 5). The 7 studies compared 364 patients (369 hips) with ALR to 318 patients (329 hips) with ALD, with a mean follow-up time ranging between 32-120 months. Five studies found significantly improved patient reported outcomes with ALR (Harris Hip Score, Merle d'Aubigné, Pain, SF-12). Several studies compared the outcomes after ALR and ALD and found statistical significance in all investigated metrics in favor of ALR. One study found a significant improvement in abduction but no other study found any difference in range of motion. No study found any difference in complication rate, revision rate or conversion to total hip arthroplasty. Although, 2 studies found ALR reduced the rate of osteoarthritic progression.

Conclusion

Current literature suggests that acetabular labral repair may result in superior patient reported outcomes. However, there appears to be no significant difference in the rate of progression to total hip arthroplasty at up to 10-year follow-up.

Level of Evidence

Level III, systematic review of Level I, II, and III studies.

Microfracture of Acetabular Rim After Segmental Labral Resection to Restore the Morphology and Function of Labrum: A Retrospective Study of More than 2 Years Follow-up

Objective

To report on the clinical outcome of patients undergoing combined arthroscopic treatment of labral resection and microfracture at the rim of acetabulum at a minimum 2‐year follow‐up.

Methods

The retrospective study included 38 patients undergoing hip arthroscopy for irreparable labral injury from 24 February 2014 to 26 February 2018. Thirteen patients were excluded owing to patient refusal of participation and concomitant diseases like synovial chondromatosis and dysplasia hip. The study group consisted of patients undergoing combined arthroscopic labral resection and microfracture at the rim of acetabulum (MICRO Group: 20 patients), arthroscopic labral resection alone (RESEC Group: five patients). Postoperative three‐dimensional (3D) double‐echo steady‐state (DESS) sequence with radial imaging at 3 Tesla were obtained and fluoroscopic image of the involved hip under distraction were used to observe the restoration of vacuum effect. Patient‐reported outcome scores (PROs) including the Harris Hip Score (HHS), Visual Analogue Score (VAS), Hip Outcome Score Activities of Daily Living Subscale (HOS‐ADL), Hip Outcome Score Sport‐Specific Subscale (HOS‐SSS) were collected and compared between two groups.

Results

All patients were followed up for at least 6 months. The follow‐up time of RESEC group is longer than MICRO group (46.6 months vs 23.9 months, P < 0.05). The 3D DESS imaging demonstrated intermediate signal intensity at the relative area where the labrum resected followed by microfracture at the acetabular rim in MICRO group. Meanwhile, regrowth of labrum‐like tissue was not observed in MRI imaging of the RESEC group. Furthermore, vacuum effect was more apparent in MICRO group compared with RESEC group. All PROs in both groups showed a statistically significant improvement at follow‐up compared with preoperative levels. RESEC group: HHS (73.0 vs 93.8, P < 0.05); HOS‐ADL (51.5 vs 89.1, P < 0.05); HOS‐SSS (47.8 vs 88.3, P < 0.05); VAS (6.4 vs 2.0, P < 0.05). MICRO group: HHS (70.5 vs 91.5, P < 0.05); HOS‐ADL (52.4 vs 87.0, P < 0.05); HOS‐SSS (48.1 vs 86.5, P < 0.05); VAS (6.3 vs 1.6, P < 0.05). One patient of MICRO group had transient neurapraxias of the pudendal nerve that resolved completely by 3 months. There showed no statistically significant difference between groups regarding the preoperative and postoperative PROs.

Conclusion

Compared to labral resection, combined arthroscopic labral resection and microfracture at the rim of acetabulum is able to fulfill the labral defect area with the potential to restore the seal effect of labrum as an effective and safe option for irreparable segmental labral tears.

Mechanical stretching induces calcification and cartilage matrix metabolism, causing degeneration of the acetabular labrum

PURPOSE

The acetabular labrum plays an important role in joint lubrication, and damage to this structure leads to osteoarthritis. This study aimed to histologically classify the degree of degeneration of the acetabular labrum and to investigate the changes in gene expression induced by mechanical stretching.

METHODS

We obtained acetabular labrum cells from patients with hip osteoarthritis during total hip arthroplasty (n = 25). The labrum was stained with safranin O, and images were histologically evaluated using a new parameter, the red/blue (R/B) value. The samples were divided into the degenerated group (D group: n = 18) and the healthy group (H group: n = 7) in accordance with the Kellgren-Lawrence (KL) grade. The cultured acetabular labral cells were subjected to loaded uniaxial cyclic tensile strain (CTS). After CTS, changes in gene expression were examined in both groups.

RESULTS

Spearman's correlation analysis revealed that the R/B value was significantly correlated with the KL grade and the Krenn score. The expression levels of genes related to cartilage metabolism, osteogenesis and angiogenesis significantly increased after CTS in the H group, while gene expression in the D group showed weaker changes after CTS than that in the H group compared to the nonstretched control group.

CONCLUSIONS

The degree of labral degeneration could be classified histologically using the R/B value and the KL grade. Mechanical stretching caused changes in gene expression that support the pathological features of labral degeneration.

Multicenter Outcomes After Revision Hip Arthroscopy: Comparative Analysis of 2-Year Outcomes After Labral Repair Versus Labral Reconstruction

BACKGROUND

There is a paucity of literature evaluating patient outcomes in patients undergoing revision labral repair and labral reconstruction.

PURPOSE

To compare outcomes in patients undergoing revision hip arthroscopy for treatment of labral tears by labral repair or labral reconstruction.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective review of a prospectively maintained multicenter database of patients undergoing hip arthroscopy was performed. An a priori power analysis determined that a total of 62 patients were required. Patients undergoing revision hip arthroscopy for labral tears with completed 2-year outcome scores were included. Patients undergoing primary hip arthroscopy, labral debridement, concomitant gluteal repair, and patients with hip dysplasia (lateral center-edge angle <20°) were excluded. Patients were grouped into revision labral repair and labral reconstruction groups. Patient demographics and patient-reported outcomes (PROs) including Hip Outcome Score - Activities of Daily Living, Hip Outcome Score - Sport Subscale, modified Harris Hip Score, international Hip Outcome Tool-12, visual analog scale for pain and satisfaction, and achievement of minimal clinically important difference (MCID) and Patient Acceptable Symptom State (PASS) were analyzed.

RESULTS

A total of 40 patients underwent revision labral repair and 55 patients underwent labral reconstruction. Patients undergoing revision labral repair were younger (mean age, 30.0 ± 10.7 years vs 34.4 ± 9.7 years; P = .048), had lower rates of labral degeneration (25.0% vs 62.7%; P = .004), and had lower rates of severe complexity of tears (21.1% vs 66.0%; P = .003). However, the labral repair group had higher rates of articular cartilage damage (62.5% vs 33.3%; P = .009). There were no differences in any preoperative or 2-year postoperative PROs. Furthermore, no differences were seen in achievement of MCID or PASS in any PRO.

CONCLUSION

In this multicenter study on revision hip arthroscopy, patients undergoing revision labral repair were younger and had better labral characteristics but greater cartilage damage compared with patients undergoing labral reconstructions. Despite these differences, patients who underwent labral repair reported similar outcomes to those undergoing labral reconstruction.

Proximal Overresection During Femoral Osteochondroplasty Negatively Affects the Distractive Stability of the Hip Joint: A Cadaver Study

BACKGROUND

Contact between the acetabular labrum and articular cartilage of the femoral head creates a suction seal that helps maintain stability of the femoral head in the acetabulum. A femoral osteochodroplasty may occasionally extend proximally into the femoral head, diminishing the articular surface area available for sealing contact.

PURPOSE

To determine whether proximal overresection decreases the rotational and distractive stability of the hip joint.

STUDY DESIGN

Controlled laboratory study.

METHODS

Six hemipelvises in the following conditions were tested: intact, T-capsulotomy, osteochondroplasty to the physeal scar, and 5- and 10-mm proximal extension. The pelvis was secured to a metal plate, and the femur was potted and attached to a multiaxial hip jig. Specimens were axially distracted using a load from 0 to 150 N. For rotational stability testing, 5 N·m of internal and external torque was applied. Both tests were performed at different angles of flexion (0°, 15°, 30°, 60°, 90°). Displacement and rotation were recorded using a 3-dimensional motion tracking system.

RESULTS

The T-capsulotomy decreased the distractive stability of the hip joint. A femoral osteochondroplasty up to the physeal scar did not seem to affect the distractive stability. However, a proximal extension of the resection by 5 and 10 mm increased axial instability at every angle of flexion tested, with the greatest increase observed at larger angles of flexion (P < .01). External rotation increased significantly after T-capsulotomy in smaller angles of flexion (0°, P = .01; 15°, P = .01; 30°, P = .03). Femoral osteochondroplasty did not create further external rotational instability, except when the resection was extended 10 mm proximally and the hip was in 90° of flexion (P = .04).

CONCLUSION

This cadaveric study demonstrated that proximal extension of osteochondroplasty into the femoral head compromises the distractive stability of the hip joint but does not affect hip rotational stability.

CLINICAL RELEVANCE

Clinically, this study highlights the importance of accuracy when performing femoral osteochondroplasty to minimize proximal extension that may increase iatrogenic instability of the hip joint.

Perpendicular drill bit alignment provides a practical guidance to determine the appropriate suture anchor insertion angle during acetabular labral repair

The safe acetabular rim angle is an anatomical measurement used to determine the safety margin when inserting suture anchors. The purpose of the present study was to find out whether aligning the drill bit perpendicularly during arthroscopic surgery can provide a reference point for determining an appropriate angle to facilitate the suture anchor insertion and to prevent extra- and intra-articular perforations. One hundred computed tomographic hips were used to reconstruct three-dimensional acetabular hip models. Each model was radially sectioned at the 4 o’clock, 3 o’clock and anterior inferior iliac spine (AIIS) positions (that corresponded mainly to the 2:20 clock position). A perpendicular reference line, representing a perpendicular drill bit alignment, was drawn for each position within the acetabular model, and its relation to the safe acetabular rim angle was measured. The length of the perpendicular reference line and the effect of gender on measurements were also evaluated. The mean safe acetabular rim angle at the 3 o’clock position was significantly smaller compared to other clock positions (P < 0.001). The perpendicular reference line was located out of the safe acetabular rim angle in 28 cases (%28), mostly in female acetabula at the 3 o’clock position, and relative to the perpendicular reference line the required minimal angle was 4° ± 2.3° to place the anchor in the safe acetabular rim angle to avoid extra-articular perforation. The perpendicular reference line was shortest at the 3 o’clock position, and its mean length was shorter in female acetabula at all clock positions (P < 0.001). Aligning the drill bit perpendicular to the acetabular opening plane during an arthroscopic anchor placement is a practical way to estimate and target the position of the safe acetabular rim angle to avoid anchor perforations. Based on measurements from a perpendicularly aligned drill bit, the drill bit should be directed towards the joint minimally by 4° to avoid extra-articular perforations and maximally by 30° to avoid intra-articular perforations.

Minimum 2-Year Functional Outcomes of Patients Undergoing Capsular Autograft Hip Labral Reconstruction

BACKGROUND

There is a paucity of literature on arthroscopic capsular autograft labral reconstruction.

PURPOSE

To report midterm functional outcomes for patients undergoing acetabular labral repair with capsular autograft labral reconstruction.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

This is a retrospective case series of prospectively collected data on patients who underwent arthroscopic acetabular labral repair by the senior surgeon between March 2013 and August 2018. The inclusion criteria for this study were adult patients aged 18 years or older who underwent primary hip arthroscopy for arthroscopic capsular autograft labral reconstruction. Exclusion criteria were <2 years of postoperative follow-up, elective disenrollment from study before 2-year follow-up, or repeat ipsilateral hip surgery before 2-year follow-up. Intraoperatively, patients underwent capsular autograft hip labral reconstruction if they were found to have a labrum with hypoplastic tissue (width <5 mm), complex tearing, or frank degeneration of native tissue. Clinical outcome data consisted of patient-reported outcome measures.

RESULTS

A total of 97 hips (94 patients) met the inclusion criteria with a mean final follow-up of 28.2 months (95% CI, 26.0-30.4). Patients had a mean age of 39.0 years (95% CI, 36.8-41.2) with a mean body mass index of 25.8 (95% CI, 24.9-26.7). When compared with baseline (40.4 [95% CI, 36.7-44.2]), the mean international Hip-Outcome Tool-33 (iHOT-33) scores were significantly greater at 3-month (60.9 [95% CI, 56.8-64.9]; P < .001), 6-month (68.8 [95% CI, 64.7-72.9]; P < .001), 12-month (73.2 [95% CI, 68.9-77.5]; P < .001), and final (76.6 [95% CI, 72.4-80.8]; P < .001) follow-up. At 2-year follow-up, 76.3%, 65.5%, and 60.8% of patients' iHOT-33 scores exceeded clinically meaningful outcome thresholds for minimally clinically important difference (MCID), patient-acceptable symptomatic state, and substantial clinical benefit, respectively.

CONCLUSIONS

In this study of 97 hips undergoing arthroscopic labral repair with capsular autograft labral reconstruction, we found favorable outcomes that exceeded the MCID thresholds in the majority of patients at a mean 28.2 months' follow-up. Future studies should compare outcomes between this technique and other methods of autograft and allograft reconstruction to determine differences in patient-reported outcomes, donor-site morbidity, and complications.

Is Arthroscopic Hip Labral Repair/Reconstruction Surgery Effective for Treating Femoroacetabular Impingement in the Presence of Osteoarthritis?

OBJECTIVE

To investigate clinical outcomes after arthroscopic labral preservation surgery for femoroacetabular impingement (FAI) in the presence of osteoarthritis (OA) compared with FAI without significant OA.

DESIGN

Retrospective case-control study.

SETTING

Department of Orthopaedic Surgery and Sports Medicine, Hospital of Academic Institute.

PATIENTS

Femoroacetabular impingement patients (n = 97; ≥35 years) undergoing arthroscopic FAI correction with labral preservation surgery from March 2009 to April 2014 were enrolled in this study.

INTERVENTIONS

Patients were divided into 2 groups: FAI group (79 patients), with Tonnis grade 0 or 1, and FAI + OA group (18 patients), with Tonnis grade 2 or 3.

MAIN OUTCOME MEASURES

We examined the clinical outcomes using the Modified Harris Hip Score (MHHS), Nonarthritic Hip Score (NAHS), and the conversion rate to total hip arthroplasty (THA).

RESULTS

No significant differences existed between the 2 groups with respect to age, sex, follow-up period, or preoperative MHHS or NAHS. The mean MHHS and NAHS at the final follow-up were significantly lower in the FAI + OA group than in the FAI group. There was a significant difference in the rate of conversion to THA and failure between the 2 groups (THA 5% vs 50%) (failure 15% vs 67%).

CONCLUSION

Patients with FAI in the presence of OA did not improve after arthroscopic labral preservation surgery and had a high conversion rate to THA.

LEVEL OF EVIDENCE

Level III.