Arthroscopic acetabular labral reconstruction: a review

No Difference in Most Reported Outcome Measures for Allograft Versus Autograft for Hip Labral Reconstruction: A Systematic Review of Comparative Studies

PURPOSE

To systematically review studies comparing outcomes of allograft versus autograft for hip labral reconstruction.

METHODS

A systematic review following guidelines established by PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) was performed in 3 databases using the terms "labrum," "hip," "acetabulum," "reconstruction," "augmentation," "allograft," and "autograft." Data on study characteristics, patient demographic characteristics, follow-up time, patient-reported outcomes (PROs), rates of revision surgery, and rates of conversion to total hip arthroplasty (THA) were collected.

RESULTS

Three studies were included, with Methodological Index for Non-randomized Studies (MINORS) scores ranging from 17 to 23. Among 92 patients receiving allografts, the mean ages ranged from 30.6 to 34.8 years; mean follow-up times, from 34.6 to 66.1 months; revision rates, from 0% to 23.6%; and conversion-to-THA rates, from 0% to 20%. Among 185 patients receiving autografts, the mean ages ranged from 34.6 to 35.9 years; mean follow-up times, from 32.7 to 80.8 months; revision rates, from 0% to 7.3%; and conversion-to-THA rates, from 0% to 6.7%. One study reported significantly higher revision rates in the allograft group. All studies reported no statistically significant differences in postoperative PROs, and all postoperative PROs significantly improved compared with preoperative PROs. Rates of achievement of the minimal clinically important difference and patient acceptable symptomatic state, reported by 1 study, were statistically similar between the 2 groups and ranged from 55.6% to 100% for the allograft group and from 53.8% to 84.6% for the autograft group.

CONCLUSIONS

There were no significant differences between allograft and autograft patients in terms of postoperative PROs; however, all PRO measures were slightly higher in allograft patients. Both revision and conversion-to-THA rates were higher in allograft patients in 2 studies, with the level of significance being reached in terms of revision in 1 study. The third study reported zero revisions and conversions to THA in allograft and autograft patients.

LEVEL OF EVIDENCE

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

Can the Acetabular Labrum Be Reconstructed With a Meniscal Allograft? An In Vivo Pig Model

BACKGROUND

No single graft type has been shown to have a benefit in acetabular labral reconstruction. The native labrum and lateral meniscus share many similarities, suggesting that the meniscus may be a promising source of graft material in labral reconstruction.

QUESTIONS/PURPOSES

Using a pig model, we sought to evaluate the healing process of fresh-frozen meniscus allograft for acetabular reconstruction by assessing (1) MRI and macroscopic observations of the meniscus allograft; (2) histologic appearance and immunohistologic evaluation of the meniscus allograft, native meniscus, and labrum; (3) microscopic assessment of the native labrum and meniscus via scanning electron microscopy; and (4) biomechanical assessment of tensile properties.

METHODS

Twelve skeletally mature male miniature Bama pigs (24 hips) were randomly divided into two groups: labral defect group (control) and lateral meniscus allograft group. The selection of Bama pig specimens was based on the similarity of their acetabular labrum to that of the human acetabular labrum, characterized by the presence of fibrocartilage-like tissue lacking blood vessels. The pigs underwent bilateral hip surgery. Briefly, a 1.5-cm-long section was resected in the anterior dorsal labrum, which was left untreated or reconstructed using an allogeneic lateral meniscus. The pigs were euthanized at 12 and 24 weeks postoperatively, and then evaluated by macroscopic observations and MRI measurement to assess the extent of coverage of the labral defect. We also performed a histologic analysis and immunohistologic evaluation to assess the composition and structure of meniscus allograft, native labrum, and meniscus, as well as scanning electron microscopy assessment of the microstructure of the native labrum and meniscus and biomechanical assessment of tensile properties.

RESULTS

Imaging measurement and macroscopic observations revealed that the resected area of the labrum was fully filled in the lateral meniscus allograft group, whereas in the control group, the labral defect remained at 24 weeks. The macroscopic scores of the meniscus allograft group (8.2 ± 0.8) were higher than those of the control groups (4.8 ± 1.0) (mean difference 3.3 [95% CI 1.6 to 5.0]; p < 0.001). Moreover, in the meniscus allograft group, histologic assessment identified fibrocartilage-like cell cluster formation at the interface between the graft and acetabulum; cells and fibers arranged perpendicularly to the acetabulum and tideline structure that were similar to those of native labrum could be observed at 24 weeks. Immunohistochemical results showed that the average optical density value of Type II collagen at the graft-acetabulum interface was increased in the meniscus allograft group at 24 weeks compared with at 12 weeks (0.259 ± 0.031 versus 0.228 ± 0.023, mean difference 0.032 [95% CI 0.003 to 0.061]; p = 0.013). Furthermore, the tensile modulus of the lateral meniscus allograft was near that of the native labrum at 24 weeks (54.7 ± 9.9 MPa versus 63.2 ± 11.3 MPa, mean difference -8.4 MPa [95% CI -38.3 to 21.4]; p = 0.212).

CONCLUSION

In a pig model, lateral meniscus allografts fully filled labral defects in labral reconstruction. Regeneration of a fibrocartilage transition zone at the graft-acetabulum interface was observed at 24 weeks.

CLINICAL RELEVANCE

The use of an autograft meniscus for labral reconstruction may be a viable option when labral tears are deemed irreparable. Before its clinical implementation, it is imperative to conduct a comparative study involving tendon grafts, which are extensively used in current clinical practice.

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.

Low Rates of 5-Year Secondary Surgery and Postoperative Complications After Primary Hip Arthroscopy in More Than 30,000 Patients

PURPOSE

To evaluate 90-day complications, 5-year secondary surgery rates, and risk factors for secondary surgery following primary hip arthroscopy performed for femoroacetabular impingement and/or labral tears using a large national dataset.

METHODS

A retrospective analysis was conducted using the PearlDiver Mariner151 database. Patients with International Classification of Diseases, Tenth Revision, diagnosis codes for femoroacetabular impingement and/or labral tear undergoing primary hip arthroscopy with femoroplasty, acetabuloplasty, and/or labral repair between 2015 and 2021 were identified. Those with concomitant International Classification of Diseases, Tenth Revision, codes for infection, neoplasm, or fracture were excluded, as were patients with a history of previous hip arthroscopy or total hip arthroplasty, or age ≥70 years. Rates of complications within 90 days of surgery were assessed. Five-year rates of secondary surgery-revision hip arthroscopy or conversion to total hip arthroplasty-were determined by Kaplan-Meier analysis, and risk factors for secondary surgery were identified by multivariate logistic regression.

RESULTS

A total of 31,623 patients underwent primary hip arthroscopy from October 2015 to April 2021, with annual volumes ranging from 5,340 to 6,343 surgeries per year. Femoroplasty was the most frequent surgical procedure (performed in 81.1% of surgical encounters), followed by labral repair (72.6%) and acetabuloplasty (33.0%). Ninety-day postoperative complication rates were low, with 1.28% of patients experiencing any complication. The 5-year secondary surgery rate was 4.9% (N = 915 patients). Multivariate logistic regression identified age <20 years (odds ratio [OR] 1.50; P < .001), female sex (OR 1.33; P < .001), class I obesity (body mass index 30-34.9: OR 1.30; P = .04), and class II/III obesity (body mass index ≥35.0: OR 1.29; P = .02) as independent predictors of secondary surgery.

CONCLUSIONS

In this study of primary hip arthroscopy, 90-day adverse events were low at 1.28%, and the 5-year secondary surgery rate was 4.9%. Age younger than 20 years, female sex, and obesity were risk factors for secondary surgery, suggesting the need for increased surveillance in these patient groups.

LEVEL OF EVIDENCE

Level IV, case series.

Durable Outcomes After Hip Labral Reconstruction at Minimum 5-Year Follow-Up: A Systematic Review

PURPOSE

To systematically review and report the mid- to long-term patient reported outcomes (PROs) following hip labral reconstruction.

METHODS

A literature search of the Pubmed, Embase, and Cochrane Library databases was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for clinical studies reporting mid- to long-term PROs at minimum five year follow-up following arthroscopic hip labral reconstruction. A quality assessment was performed using the Methodological Index of Non-Randomized Studies (MINORS) grading system. Data collection included study characteristics, demographics, indications, radiographic metrics, perioperative findings, surgical technique, baseline and most recent PROs, and subsequent surgeries.

RESULTS

Four studies met inclusion criteria, with 182 hips (age range, 27.9 to 38.7 years) undergoing labral reconstruction in primary and revision hip surgery with minimum five year follow-up. There were three level III studies and one level IV study, with an average MINORS score of 16.6. All studies cited labral tissue characteristics as a factor for surgical indications, including the quality and/or size of the labrum. Three studies performed segmental labral reconstructions, while another study utilized a circumferential technique. Varying grafts were selected, including hamstring autograft/allograft, ligamentum teres autograft, iliotibial band autograft, and tensor fascia lata autograft. All studies demonstrated improved PROs from baseline to most recent follow-up, with four studies reporting modified Harris Hip Score (mHHS) values that increased from baseline (range, 58.9 to 66.8) to most recent follow-up (range, 80.1 to 86.3). After labral reconstruction, rates of revision arthroscopy ranged from 4.8% to 13.3% and conversion to total hip arthroplasty ranged from 1.6% to 27%.

CONCLUSION

Improved PROs were observed in all studies at minimum 5-year follow-up, suggesting that labral reconstruction can offer durable results beyond short-term follow-up. While surgical indications for all studies included labral tissue characteristics, differing graft selection and surgical techniques were utilized across studies, limiting the ability to determine an optimal treatment approach.

Minimum 10-year Survivorship and Clinical Outcomes Following Primary Hip Arthroscopy with Acetabular Microfracture

PURPOSE

To report minimum 10-year follow-up survivorship, defined as non-conversion to total hip arthroplasty (THA), and patient-reported outcome scores (PROS) after primary hip arthroscopy with acetabular microfracture in the setting of femoroacetabular impingement syndrome (FAIS) and acetabular chondral lesions, respectively.

METHODS

Data were prospectively collected and retrospectively analyzed on all patients who underwent a primary hip arthroscopy and received an acetabular microfracture between June 2009 and January 2011. Patients with a minimum 10-year follow-up for the modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), and the visual analog scale (VAS) for pain were included. If available, the minimum 10-year follow-up for the Hip Outcome Score-Sport-Specific Subscale was reported. The demographics, intraoperative findings, surgical procedures, PROS, rate of achieving the minimal clinical important difference (MCID), and secondary surgeries were analyzed and reported.

RESULTS

Twenty-two hips (20 patients) were included in the study, and the mean follow-up time was 124.5 ± 2.2 months. There were 17 hips (77.3%) from males and 5 hips (22.7%) from females. The average patient age at the time of surgery was 42.3 years ± 9.6. All patients on average experienced statistically significant improvement (P < .05) between preoperative and minimum 10-year follow-up scores for all PROs. In total, 77.3% of the patients did not require conversion to THA. Additionally, 83.3% of the patients achieved the MCID for the mHHS, NAHS, and VAS for pain.

CONCLUSION

At a minimum 10-year follow-up, survivorship of 77.3% was reported for patients who underwent primary hip arthroscopy with acetabular microfracture for the treatment of FAIS and focal/full-thickness acetabular cartilage lesions. Further, in the patients that did not require THA conversion, significant improvement in all PROS was demonstrated.

LEVEL OF EVIDENCE

IV, case-series study.

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.

Effect of COVID-19 pandemic on hip preservation surgery—a prospective surveillance from the UK Non-Arthroplasty Hip Registry

A multi-centre, registry-based cohort study was conducted to assess the effect of the coronavirus disease 2019 (COVID-19) pandemic on the provision of non-arthroplasty hip surgery (NAHS) in the UK by (i) comparing the number of NAHS performed during the pandemic to pre-pandemic levels, (ii) prospectively auditing compliance to established guidance and (iii) evaluating post-operative outcomes and their predictors. Patients who underwent NAHS during the pandemic/pre-pandemic were selected from the Non-Arthroplasty Hip Registry, which collects demographic, procedural and pre-operative outcome data. Patients during the pandemic period were emailed separate COVID-19 surveillance questionnaires, which evaluated adherence to guidelines and post-operative outcomes. Fisher’s exact tests and logistic regression were used to identify predictors for developing COVID-19 and being re-admitted into hospital, post-surgery. There was a 64% reduction of NAHS performed during the pandemic compared to the pre-pandemic period. Ninety-nine percent of participants self-isolated, and 96.8% received screening, pre-operatively. No participant was COVID-19-positive peri-operatively. Post-operatively, participants had an intensive care unit admission rate of 2%, median hospital stay of 1 day, hospital readmission rate of 4.2%, COVID-19 development rate of 2.3% and a thromboembolic complication rate of 0.32%. No COVID-19-positive patient developed adverse post-operative outcomes. Participants who developed COVID-19 post-operatively had greater odds of having undergone osteotomy in comparison to arthroscopic surgery (P = 0.036, odds ratio = 5.36). NAHS was performed with good compliance to established guidance, and adverse operative outcomes remained low. If guidance is followed, the risk of COVID-19 post-op development is low. Although bigger operations have a slightly higher risk, this does not impact their prognosis.