The acetabular labrum seal: a poroelastic finite element model

Arthroscopic Repair of Acetabular Labral Tears Associated with Femoroacetabular Impingement: 7-10 Years of Long-Term Follow-up Results

Background

The purpose of this study is to report the long-term follow-up results of arthroscopic repair of acetabular labral tears with femoroacetabular impingement (FAI).

Methods

Of 45 patients who underwent arthroscopic labral repair under the diagnosis of acetabular labral tears with FAI from January 2008 to December 2010 and met our inclusion criteria, 41 patients who were available for a long-term follow-up were included in the analysis. We compared the long-term follow-up results with the previously reported short-term follow-up results of the same patients. The mean follow-up period was 92.4 months (range, 85 to 117 months). There were 21 males and 20 females, and their mean age at surgery was 34.6 years (range, 16 to 54 years). A modified Harris hip score (mHHS), visual analog scale (VAS), hip outcome score-activity of daily living (HOS-ADL), hip outcome score-activity-sport-specific subscale (HOS-SSS), and patient satisfaction were used for evaluation of the clinical results and Tönnis grade for detection of early osteoarthritis (OA).

Results

The mean VAS score decreased from 6.4 points to 1.8 points (p < 0.001), the mean mHHS increased from 59.5 points to 86.8 points (p < 0.001), and the mean HOS-ADL and HOS-SSS increased from 58.3 and 51.2, respectively, to 85.2 and 82.4, respectively (p < 0.001), between the preoperative and last follow-up assessment. The mean patient satisfaction score was 7.6 of 10. The average Tönnis grade at the last follow-up (0.67; range, 0 to 3) was not significantly different from the preoperative average (0.51; range, 0 to 1). Only one case was converted to total hip arthroplasty because of progression of OA at 8 years after surgery. Five cases of secondary arthroscopic surgery were performed before maximum 5 years postoperatively because of labro-synovial adhesion (three cases), pullout of the suture anchor (one case) or symptomatic heterotrophic ossification (one case).

Conclusions

The clinical and radiological long-term follow-up revealed that improvement after arthroscopic labral repair and osteoplasty for FAI were maintained in most cases without significant progression of arthritis. Anatomical recovery of the acetabular labrum was associated with the improvement of clinical symptoms.

Reconstruction Guide for the Measurement of Segmental Labral Insufficiency: An Alternative Technique for Acetabular Labral Reconstruction

The acetabular labrum is a dynamic structure important for both hip stability and functional motion. Given its importance, injuries to the labrum result in significant symptomatic dysfunction caused by altered hip kinematics. Although labral repair represents the standard for symptomatic labral tears with underlying bony deformity, complex labral tears or those with significant degeneration may not be amenable to repair and require labral reconstruction. Labral reconstruction has been shown to restore intra-articular fluid pressurization to levels similar to those in the intact state, and cohort studies have increasingly demonstrated significant improvement in patient-reported outcomes at midterm follow-up. A critical component of successful labral reconstruction is accurate measurement of the graft length to restore native anatomy and kinematics of the hip. The purpose of this Technical Note is to describe a way to accurately measure graft length required for labral reconstruction.

In Revision Hip Arthroscopy, Labral Reconstruction Can Address a Deficient Labrum, but Labral Repair Retains Its Role for the Reparable Labrum: A Matched Control Study

BACKGROUND

Revision hip arthroscopy is increasingly common and often addresses acetabular labrum pathology. There is a lack of consensus on indications or outcomes of revision labral repair versus reconstruction.

PURPOSE

To report clinical outcomes of labral reconstruction during revision hip arthroscopy at minimum 2-year follow-up as compared with pair-matched labral repair during revision hip arthroscopy (control group) and to suggest a decision-making algorithm for labral treatment in revision hip arthroscopy.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients who underwent revision hip arthroscopy with labral reconstruction were matched 1:2 with patients who underwent revision arthroscopic labral repair. Patients were matched according to age, sex, and body mass index. Outcome scores, including the modified Harris Hip Score (mHHS), Non-Arthritic Hip Score, Hip Outcome Score-Sport-Specific Subscale, and a visual analog scale for pain, were collected preoperatively and at minimum 2-year follow-up. At latest follow-up, patient satisfaction on a 0-10 scale and the abbreviated International Hip Outcome Tool (iHOT-12) were collected. Complications, subsequent arthroscopies, and conversion to total hip arthroplasty were collected as well.

RESULTS

A total of 15 revision labral reconstructions were pair matched to 30 revision labral repairs. The reconstructions had fewer isolated Seldes type I detachments ( P = .008) and lower postoperative lateral center-edge angle, but there were otherwise no significant differences in demographics, radiographics, intraoperative findings, or procedures. Both groups demonstrated significant improvements in all outcomes and visual analog scale at minimum 2-year follow-up. The revision repairs trended toward better preoperative scores: mHHS (mean ± SD: 59.3 ± 16.5 vs 54.2 ± 16.0), Non-Arthritic Hip Score (61.0 ± 16.7 vs 51.2 ± 17.6), Hip Outcome Score-Sport-Specific Subscale (39.6 ± 25.1 vs 30.5 ± 22.1), and visual analog scale (5.8 ± 1.8 vs 6.2 ± 2.2). At follow-up, the revision repair group had significantly higher mHHS (84.1 ± 14.8 vs 72.0 ± 18.3, P = .043) and iHOT-12 (72.2 ± 23.3 vs 49.0 ± 27.6, P = .023) scores than the reconstruction group. The magnitudes of pre- to postoperative improvement between the groups were comparable. The groups also had comparable rates of complications: 1 case of numbness in each group ( P > .999), subsequent arthroscopies (repair: n = 2, 6.5%; revision: n = 3, 20%; P = .150), and conversion to total hip arthroplasty (1 patient in each group, P > .999).

CONCLUSION

Labral reconstruction safely and effectively treats irreparable labra in revision hip arthroscopy. However, labral repair is another treatment option for reparable labra, yielding similar magnitude of improvement. A proposed algorithm may assist in surgical decision making to achieve optimal outcomes based on the condition and history of each patient's acetabular labrum.

The Effect of Charge and Mechanical Loading on Antibody Diffusion Through the Articular Surface of Cartilage

Molecular transport of osteoarthritis (OA) therapeutics within articular cartilage is influenced by many factors, such as solute charge, that have yet to be fully understood. This study characterizes how solute charge influences local diffusion and convective transport of antibodies within the heterogeneous cartilage matrix. Three fluorescently tagged solutes of varying isoelectric point (pI) (4.7–5.9) were tested in either cyclic or passive cartilage loading conditions. In each case, local diffusivities were calculated based on local fluorescence in the cartilage sample, as observed by confocal microscopy. In agreement with past research, local solute diffusivities within the heterogeneous cartilage matrix were highest around 200–275 μm from the articular surface, but 3–4 times lower at the articular surface and in the deeper zones of the tissue. Transport of all 150 kDa solutes was significantly increased by the application of mechanical loading at 1 Hz, but local transport enhancement was not significantly affected by changes in solute isoelectric point. More positively charged solutes (higher pI) had significantly higher local diffusivities 200–275 μm from the tissue surface, but no other differences were observed. This implies that there are certain regions of cartilage that are more sensitive to changes in solute charge than others, which could be useful for future development of OA therapeutics.

Arthroscopic acetabular labral reconstruction with rectus femoris tendon autograft: Our experiences and early results

Background

The native labrum has been shown to play a critical role in the maintenance of overall health of the cartilage of the hip. Disruption of the labral seal could be detrimental to the overall nutrition of the cartilage, leading to its premature degeneration.

Purpose

This study sought to investigate patients undergoing labral reconstruction with indirect head of rectus femoris autograft, to determine the subjective improvement in pain they experienced, the complications and reoperation rates including conversion to Total hip replacement(THR).

Method

We retrospectively reviewed all 7 patients who underwent labral reconstruction using indirect head of the rectus femoris tendon autograft between January 2013 to October 2015. We assessed improvement in pain and function, complications, and subsequent surgery. The minimum follow-up was 12 months (average, 15 months; range, 12-18 months).

Results

All patients reported subjective improvement in preoperative pain and function. The mean modified Harris Hip Score (mHHS) improved significantly from 56 (54-60) preoperatively to 93 (90-97)) at mean latest follow-up. The mean change of mHHS was 36 (30-43) and mean postoperative patient satisfaction score was 9.1. We observed no radiological progression of arthritis as well as no patient had revision procedure including total hip replacement.

Conclusion

Acetabular labrum reconstruction for irreparable labral tears in young patients with no significant arthritis, using indirect head of the rectus femoris tendon autograft is a new technique that shows improvement in pain and function post-operatively. Long-term follow-up results with higher quality studies will be necessary to further define the role of labral reconstruction in hip preservation surgery.

Simultaneous acetabular labrum and ligamentum teres reconstruction: a case report

This study aims to present the surgical technique for reconstructing both the acetabular labrum and the ligamentum teres and to describe the early outcomes of this procedure in a 15-year-old male with recurrent hip instability. A 15-year-old patient with recurrent left hip dislocation, hip joint instability and failed non-operative intervention presented following two left hip dislocations. A labral reconstruction was performed utilizing an iliotibial band allograft tissue with a concomitant ligamentum teres reconstruction using a tibialis anterior allograft. The patient was assessed pre- and postoperatively using modified Harris Hip Score, Lower Extremity Functional Scale and Visual Analogue Scale for pain and satisfaction. The patient reported improvement on all measures, including hip stability 14 months following surgery. The patient has not reported any episodes or subjective feelings of instability, has not required further surgical procedures in the hip and has returned to full sports participation. This case report demonstrates a technique for and early outcomes of simultaneous arthroscopic ligamentum teres and acetabular labrum reconstruction in a patient with recurrent hip instability. Short-term outcomes suggest improved hip stability, reduced pain, high patient satisfaction and return to pre-injury activities at 14 months postoperative in this single case report.

Hip chondrolabral mechanics during activities of daily living: Role of the labrum and interstitial fluid pressurization

Osteoarthritis of the hip can result from mechanical factors, which can be studied using finite element (FE) analysis. FE studies of the hip often assume there is no significant loss of fluid pressurization in the articular cartilage during simulated activities and approximate the material as incompressible and elastic. This study examined the conditions under which interstitial fluid load support remains sustained during physiological motions, as well as the role of the labrum in maintaining fluid load support and the effect of its presence on the solid phase of the surrounding cartilage. We found that dynamic motions of gait and squatting maintained consistent fluid load support between cycles, while static single-leg stance experienced slight fluid depressurization with significant reduction of solid phase stress and strain. Presence of the labrum did not significantly influence fluid load support within the articular cartilage, but prevented deformation at the cartilage edge, leading to lower stress and strain conditions in the cartilage. A morphologically accurate representation of collagen fibril orientation through the thickness of the articular cartilage was not necessary to predict fluid load support. However, comparison with simplified fibril reinforcement underscored the physiological importance. The results of this study demonstrate that an elastic incompressible material approximation is reasonable for modeling a limited number of cyclic motions of gait and squatting without significant loss of accuracy, but is not appropriate for static motions or numerous repeated motions. Additionally, effects seen from removal of the labrum motivate evaluation of labral reattachment strategies in the context of labral repair.

Labral augmentation with ligamentum capitis femoris: presentation of a new technique and preliminary results

Preservation of an intact labrum and reconstruction of a deficient or worn acetabular labrum are accepted techniques in modern hip surgery. If the remaining labrum is very thin, its intact tip can be preserved and its volume restored with a ligamentum teres graft. Technique and preliminary results of this augmentation technique are presented. Labral augmentation was performed in 16 hips (11 rights) in 16 patients (7 males, mean age 29 years) during surgical dislocation for treatment of femoroacetabular impingement. The acetabular index, lateral center edge angle, asphericity angle and acetabular retroversion index were determined on preoperative X-rays and magnetic resonance imaging. The pre- and postoperative Merle d'Aubigné and Postel score (MdA) was calculated and the Oxford Hip Score (OHS) obtained after 1 year. There were seven Grade 1 and nine Grade 0 hips (Tönnis classification). Mean lateral center edge was 29°. The mean acetabular index was 1.85°. Mean asphericity angle was 62.5°. Mean acetabular retroversion index was 23.4%. Mean MdA improved from 14.5 preoperatively to 17 at 1 year (P < 0.0001). Mean OHS after 1 year was 42. Previous surgery was a risk factor for inferior results: OHS was 44.5 in hips without versus 26 in hips with previous surgery. Mean MdA improved from 15 to 17.5 in patients without previous surgery versus 14 to 16 for the group with previous surgery. Augmentation of the labrum using ligamentum teres shows good clinical results after 1 year. Patients with previous hip surgery had inferior results.

Labral cuff refixation in the hip: rationale and operative technique for preserving the chondrolabral interface for labral repair: a case series

Arthroscopic labral 'takedown' and refixation is utilized to permit adequate visualization and resection of the acetabular rim deformity, in patients with pincer or mixed femoroacetabular impingement. Deficiencies exist in present techniques, which include disruption of vital anatomical support and vascular structures to the labrum and chondrolabral junction, drill or anchor articular penetration risk, bunching, elevation and instability of the labrum. A new operative technique is described which preserves the important chondrolabral interface, accurately restoring the 'flap seal' of the acetabular labrum while minimizing vascular disruption and reducing the risk of drill and anchor penetration. A prospective series of 123 consecutive cases of pincer or mixed femoroacetabular impingement, treated with arthroscopic labral cuff refixation and preservation of the chondrolabral interface, is reported; operative technique and 2-year outcomes are presented.

Basics in hip chondrolabral lesions and state of the art

Chondrolabral complex is a weak point along an histological transition zone. Most cartilage and labral lesions in the femoroacetabular impingement syndrome are located in this area. Different classifications are used to evaluate the severity and predict the prognosis of chondrolabral complex injuries. Acetabular Labrum Articular Disruption (ALAD) and Multicenter Arthroscopy of the Hip Outcomes Research Network (MAHORN) classifications are commonly used with a prognosis and treatment implication. Treatment of chondrolabral lesions detected on magnetic resonance imaging (MRI), should only be considered when clinical symptoms are presented. A wide range of treatment options include debridement with or without microfracture, repair or regenerate therapies. The future of hip joint preservation should be directed towards to the development of the treatment of chondrolabral injuries.

Outcomes following arthroscopic hip segmental labral reconstruction using autologous capsule tissue or indirect head of the rectus tendon

The purpose of this study was to determine the outcomes following segmental labral reconstruction (labral defects measuring <1 cm) using a segment of capsular tissue or a segment of the indirect head of rectus femoris tendon. Eleven patients (five females and six males) underwent segmental labral reconstruction using a segment of capsule (eight patients) or indirect head of rectus tendon (three patients) by a single surgeon from March 2005 to October 2012. The average age of the patients was 35 years old (range, 20-51 years). Data collected included the pre- and post-operative Hip Outcome Score (HOS-ADL and HOS-SS), the modified Harris Hip Score and patient satisfaction rate (1 = unsatisfied, 10 = very satisfied), complications, necessity of revision hip arthroscopy and conversion to total hip arthroplasty. Average follow-up time was at 62 months (range, 9-120 months). No patient required revision hip arthroscopy or converted to total hip arthroplasty. The HOS-ADL significantly improved from 73 to 89 (P < 0.05). The HOS-SS showed significant improvement from 52 to 79 and the modified Harris Hip Score significantly improved from 66 to 89. Median patient satisfaction rate was 9 out of 10 (range, 3-10). In a small sample, the arthroscopic hip segmental labral reconstruction showed significant improvement in patient-reported outcomes. This treatment provides an option in cases of small labrum defects (<1 cm) or deficits in patients while providing improved function and high patient satisfaction.

Use of the painDETECT questionnaire to differentiate the nature of hip pain associated with a labrum tear

The nature of pain associated with a labrum tear of the hip joint can vary widely among patients and does not always correlate with findings from diagnostic imaging. Identifying the components of the pain (nociceptive, neuropathic, or mixed pattern) is important to direct treatment. This report aimed to describe the use of the painDETECT questionnaire as a screening tool in order to classify the nature of the pain in three patients who presented with pain that was atypical for a labrum tear. The painDETECT questionnaire was an effective tool to identify appropriate pain management strategies in each case.

Arthroscopic Labral Base Repair in the Hip: 5-Year Minimum Clinical Outcomes

BACKGROUND

Arthroscopic labral base repair (LBR) in the hip is a previously described technique designed to restore the native functional anatomy of the labrum by reproducing its seal against the femoral head. LBR has been shown to have good short-term outcomes. Hypothesis/Purpose: The purpose was to evaluate clinical outcomes of an LBR cohort with a minimum 5-year follow-up. It was hypothesized that patients who underwent LBR would continue to have significant improvement from their preoperative scores and maintain scores similar to their 2-year outcomes.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Data for patients undergoing primary hip arthroscopic surgery with LBR from February 2008 to May 2011 with a minimum 5-year follow-up were prospectively collected and retrospectively reviewed. Patients with preoperative Tonnis osteoarthritis grade ≥2, previous hip conditions (slipped capital femoral epiphysis, avascular necrosis, Legg-Calv-Perthes disease), severe dysplasia (lateral center-edge angle <18°), or previous ipsilateral hip surgery were excluded. Statistical equivalence tests evaluated patient-reported outcomes (PROs) including the modified Harris Hip Score (mHHS), Non-Arthritic Hip Score (NAHS), Hip Outcome Score-Sport-Specific Subscale (HOS-SSS), visual analog scale (VAS) for pain, and patient satisfaction (0-10 scale; 10 = very satisfied).

RESULTS

Of the 70 patients (74 hips) who met inclusion and exclusion criteria, 60 (85.7%) patients (64 hips) were available at a minimum 5-year follow-up. All PRO scores significantly improved from preoperative values with a mean follow-up of 67.8 ± 7.4 months (range, 60.0-89.7 months). The mean mHHS increased from 64.4 ±13.8 to 85.3 ± 17.7 ( P < .001), the mean NAHS from 63.7 ± 17.0 to 87.0 ± 14.7 ( P < .001), and the mean HOS-SSS from 47.1 ± 23.2 to 76.5 ± 25.9 ( P < .001). The mean VAS score decreased from 5.9 ± 2.4 to 2.0 ± 2.1 ( P < .001). The mean patient satisfaction score was 8.1 ± 2.0. The improvement in PRO scores was sustained from 2- to 5-year follow-up. At 2 and 5 years, survivorship rates were 96.9% and 90.6%, respectively, and the respective secondary arthroscopic surgery rates were 10.9% (7/64) and 17.2% (11/64).

CONCLUSION

At a minimum 5-year follow-up, arthroscopic LBR continued to be a successful procedure and valid technique based on 3 PROs, the VAS, patient satisfaction, and survivorship. Significantly improved outcome scores were maintained compared with preoperative values and showed no signs of deterioration from the 2-year scores. The long-term survivorship of hip arthroscopic surgery has yet to be determined; however, these midterm results demonstrate the rates of additional procedures (both secondary arthroscopic surgery and conversion to total hip arthroplasty), that may be necessary after 2 years.

Surgical Management of the Aging Athlete

Epidemiologic data show that the number of middle aged (>40 yr) and elderly (>65 yr) individuals continues to increase steadily, creating an expanding need for sports medicine care. Management of injuries in this subset of patients is expanding well beyond sustaining a patient's ability to perform activities of daily living. In fact, many older individuals increasingly expect to maintain reasonably high activity levels throughout their lifespan as well as after musculoskeletal injury. While a number of the emerging physiologic benefits of physical activity in older patients have been outlined, no recent review has outlined the current best surgical techniques, rehabilitation protocols, and return-to-sport recommendations for older athletes after soft-tissue repair or reconstruction as well as joint replacement. The goal of orthopaedic care in the elderly patient is shifting from simple pain relief toward return to athletic activity.

Arthroscopic acetabuloplasty without labral detachment for focal pincer-type impingement: a minimum 2-year follow-up

In order to access and resect the acetabular rim, arthroscopic acetabuloplasty was described with labral detachment. When the chondrolabral junction remains intact, acetabuloplasty and labral refixation can be performed maintaining an unharmed labrum. We aimed to evaluate the outcome of a group of patients treated with arthroscopic acetabuloplasty without labral detachment. During the study period, we retrospectively analysed 44 patients with pincer-type o combined impingement and an intact chondroblabral junction, with an average follow-up of 32 months (range: 27-38). We excluded patients with isolated CAM-type impingement and previous hip pathology. Radiographs were analysed to define impingement and classify grade of osteoarthritis. Clinical evaluation consisted of pre-operative and post-operative modified Harris hip score (mHHS) and WOMAC as well as post-operative visual analogue scale (VAS) of pain and satisfaction. Reoperations were considered surgical failures for purposes of survival analysis. Mean mHHS changed from 51.06 (SD 4.81) pre-operatively to 84.97 (SD 12.79) post-operatively. Pre-operative WOMAC was 29.18 (SD 8) and post-operative, 13.10 (SD 11). Post-operative VAS was 7.5 and 2.27 for satisfaction and pain, respectively. When comparing patients with Tönnis 0 to those with Tönnis 1, the former showed better results regarding post-operative mHHS (89.9 s versus 77.85, P = 0.03), pain VAS (1.5 versus 6.3, P = 0.03) and satisfaction VAS (8.2 versus 6.3, P = 0.01). Survival was 100% at 24 months and 76% at 40 months (95% CI: 35-98%). Arthroscopic acetabuloplasty without labral detachment achieved good clinical outcomes. Slight degenerative changes on radiographs correlated with poorer clinical outcomes.

Translatory hip kinematics measured with optoelectronic surgical navigation

PURPOSE

An optoelectronic surgical navigation system was used to detect small but measurable translational motion of human hip cadavers in high-range passive motions. Kinematic data were also examined to demonstrate the role of soft tissues in constraining hip translation.

METHODS

Twelve cadaver hips were scanned using CT, instrumented for navigation, and passively taken through motion assessment. Center of the femoral head was tracked in the acetabular coordinates. Maximum non-impinging translation of the femoral head for each specimen hip was reported. This was repeated for 5 tissue states: whole, exposed to the capsule, partially or fully incised capsule, resection of the ligamentum teres and labrectomy. Femoral motions were compared to the reported value for ideal ball and socket model.

RESULTS

Whole and exposed hips underwent maximal translations of [Formula: see text] and [Formula: see text] mm, respectively. These translational motions were statistically significantly different from reported value for a purely spherical joint, [Formula: see text]. Further tissue removal almost always significantly increased maximum non-impingement translational motion with [Formula: see text].

CONCLUSION

We found subtle but definite translations in every cadaver hip. There was no consistent pattern of translation. It is possible to use the surgical navigation systems for the assessment of human hip kinematics intra-operatively and improve the treatment of total hip arthroplasty patients by the knowledge of the fact that their hips translate. Better procedure selection and implantation optimization may arise from improved understanding of the motion of this critically important human joint.

Does duration of symptoms affect clinical outcome after hip arthroscopy for labral tears? Analysis of prospectively collected outcomes with minimum 2-year follow-up

Limited research exists on the possible association between duration of symptoms and clinical outcomes following hip arthroscopy for labral tears. The purpose of this study was to evaluate whether duration of symptoms affected clinical and patient-reported outcome (PRO) scores following hip arthroscopy for labral tears. From 2008 to 2011, data were collected prospectively on all patients undergoing primary hip arthroscopy for labral tears. Workers' compensation cases, dysplasia cases and patients with previous ipsilateral hip surgeries were excluded. A total of 738 patients were identified with a minimum of 2-year follow-up, and clinical and PRO data were available for 680 patients. Uni- and multivariate analyses were performed to determine the relationship between duration of symptoms along with other variables and PROs. Overall, patients experienced significant improvements in all clinical and PRO scores. Results of univariate analysis revealed that all PROs were negatively associated with increasing Log₁₀ months of symptoms as were pain and satisfaction scores. During multivariate analyses, increasing Log₁₀ months of symptoms, age, body mass index and trauma were all negatively associated with PROs (P  < 0.05). Our study demonstrates that clinical and PRO scores were negatively associated with increasing duration of symptoms prior to hip arthroscopy for treatment of labral tears. Although this implies that delay in treatment may adversely affect outcome, conservative treatment remains the gold standard first line of treatment. Surgeons should incorporate this information into their treatment algorithm to maximize patient outcomes following treatment for labral tears. Level of evidence: Level IV, prospective case series.

Mechanical strains passing through the acetabular labrum modify its shape during hip motion: an anatomical study

PURPOSE

The function of the hip labrum during hip motion remains poorly known. Our hypothesis was that acetabular labrum will deform and change its shape during adduction to abduction movement consecutively to variation of strains passing from the acetabulum to the femoral head. An ex vivo anatomical study was conducted to analyse the morphological parameters variation of the mid-portion of the labrum (length, thickness, shape, deformation) as well as femoro-labral strains during hip adduction to abduction movement.

METHODS

Ten fresh-frozen, unpaired human cadaver hemi-pelvises were obtained. To best approximate the clinical reality, fresh-frozen cadaver tissues were utilized. The hemi-pelvises were split sagittally in two equal parts through a plane crossing the femoral neck and femoral head centres. The hemi-pelvises were rigidly mounted on a test platform using a custom-made fixture, and a seven hundred Newton load was applied through the iliac wing, with a unidirectional movement (adduction/abduction) of the acetabulum above the fixed femur. Variations of strain passing from the labrum to the femoral head or neck were analysed using captors fixed on the acetabular edge.

RESULTS

From 20° to 40° of abduction labral length decreased from a median of 5.8 (5.5-6.4 mm) to 4.6 (4-5.4 mm), labral edge angle increased from a median of 33.1 (31.1°-40°) to 52.3 (41.4°-58.8°), labral sectional area decreased from a median of 22.1 (17-27.1 mm²) to 14.2 (12-16.8 mm²) all p = 0.001. Femoro-labral strains were maximal at 40° of abduction [median 0.1 N mm^-2 (0.1-3.1 N mm^-2)] and minimal at 30° adduction (median 0 N mm^-2 (0-0.1 N mm^-2) and p = 0.001).

CONCLUSION

The morphological variations of the mid-portion of the labrum during hip motion reflect strains passing from the labrum to the femoral head. Those elements may provide clues to understand the mechanical role of the labrum during abduction. The acetabular labrum bears a direct mechanical role during hip motion, thus resecting the hip's labrum during surgery might be detrimental for hip joint's biomechanics as it might modify strains distribution between the acetabulum and femur.

Patient-specific chondrolabral contact mechanics in patients with acetabular dysplasia following treatment with peri-acetabular osteotomy

OBJECTIVE

Using a validated, patient-specific finite element (FE) modeling protocol, we evaluated cartilage and labrum (i.e., chondrolabral) mechanics before and after peri-acetabular osteotomy (PAO) to provide insight into the ability of this procedure to improve mechanics in dysplastic hips.

DESIGN

Five patients with acetabular dysplasia were recruited in this case-controlled, prospective study. Models, which included anatomy for bone, cartilage, and labrum, were generated from computed tomography (CT) arthrography scans acquired before and after PAO. Cartilage and labrum contact stress and contact area were quantified overall and regionally. Load supported by the labrum, expressed as a percentage of the total hip force, was analyzed.

RESULTS

Percent cartilage contact area increased post-operatively overall, medially, and superiorly. Peak acetabular contact stress decreased overall, laterally, anteriorly, and superiorly. Average contact stress decreased overall, laterally, anteriorly, and posteriorly. Only average contact stress on the superior labrum and peak labrum stress overall decreased. Load supported by the labrum did not change significantly.

CONCLUSIONS

PAO was efficacious at medializing cartilage contact and reducing cartilage contact stresses, and therefore may minimize deleterious loading to focal cartilage lesions, subchondral cysts, and cartilage delaminations often observed in the lateral acetabulum of dysplastic hips. However, the excessively prominent, hypertrophied labrum of dysplastic hips remains in contact with the femoral head, which continues to load the labrum following PAO. The clinical ramifications of continued labral loading following PAO are not known. However, it is plausible that failure to reduce the load experienced by the labrum could result in end-stage hip OA following PAO.

Labral reconstruction with tendon allograft: histological findings show revascularization at 8 weeks from implantation

This description shows the histological findings of a peroneus brevis tendon allograft used for labral reconstruction, implanted 8 weeks before being retrieved due to a postoperative complication unrelated to the graft. As far as we have knowledge this is the first description about revascularization of an allograft used for hip labral reconstruction. The histological report of the removed peroneus brevis tendon allograft shows evidence of vascular ingrowth represented by small vessels with a thin muscular wall in all layers of the graft and cellular migration mainly represented by mature fibroblasts.

Arthroscopic Hip Labral Augmentation Technique With Iliotibial Band Graft

The importance of the acetabular labrum has been well documented for the function and overall health of the hip joint. Several biomechanical studies have shown the sealing effect of the acetabular labrum. In the past decade, labral repair procedures have gained increased attention, with the literature suggesting that the outcomes after hip arthroscopy are directly related to labral preservation. However, a primary labral repair can be challenging in cases of hypoplastic, ossified, or complex and irreparable labral tears in which there is insufficient tissue to perform a primary repair. For these cases, labral reconstruction becomes a viable option with good outcomes at short-term and midterm follow-up. A subset of these patients may show viable remnants of the labral circumferential fibers but, because of the low tissue volume, these remnant fibers are unable to maintain the suction seal. In this situation, a labral augmentation may be a viable alternative to labral reconstruction while preserving as much native labral tissue as possible. The purpose of this Technical Note is to describe an arthroscopic hip labral augmentation technique using iliotibial band autograft or allograft.

Decision Making for Labral Treatment in the Hip: Repair Versus Débridement Versus Reconstruction

The role and function of the acetabular labrum have been studied extensively in the past decade. Recent studies have proposed that, in addition to causing pain and mechanical symptoms, labral tears may accelerate arthritis. Labral preservation is believed to be important because of the role the labrum plays in maintaining a healthy joint. Treatment of the acetabular labrum is becoming one of the fastest growing fields in orthopaedics; therefore, the treatment decision-making process must be refined. Currently, three commonly practiced labral treatments are available: repair, débridement, and reconstruction. Arguments for and against each treatment option exist in the literature. Reviewing the currently proposed indicators for labral tear treatments in conjunction with the treatment procedures yields a thorough decision-making guide for choosing the appropriate labral procedure.

Long-term Outcome of Unconstrained Primary Total Hip Arthroplasty in Ipsilateral Residual Poliomyelitis

Incapacitating articular sequelae in the hip joint have been described for patients with late effects of poliomyelitis. In these patients, total hip arthroplasty (THA) has been associated with a substantial rate of dislocation. This study was conducted to evaluate the long-term clinical and radiologic outcomes of unconstrained THA in this specific group of patients. The study included 6 patients with ipsilateral polio who underwent primary THA between 1985 and 2006. Patients with polio who underwent THA on the nonparalytic limb were excluded. Mean follow-up was 119.5 months (minimum, 84 months). Clinical outcomes were evaluated with the modified Harris Hip Score (mHHS) and the visual analog scale (VAS) pain score. Radiographs were examined to identify the cause of complications and determine the need for revision surgery. All patients showed significantly better functional results when preoperative and postoperative mHHS (67.58 vs 87.33, respectively; P=.002) and VAS pain score (7.66 vs 2, respectively; P=.0003) were compared. Although 2 cases of instability were diagnosed, only 1 patient needed acetabular revision as a result of component malpositioning. None of the patients had component loosening, osteolysis, or infection. Unconstrained THA in the affected limb of patients with poliomyelitis showed favorable long-term clinical results, with improved function and pain relief. Nevertheless, instability may be a more frequent complication in this group of patients compared with the general population. [Orthopedics. 2017; 40(2):e255-e261.].

Histological changes of the acetabular labrum in coxarthrosis: labral degeneration and repair

INTRODUCTION

The current study was designed to describe types of histological changes within the acetabular labrum in the advanced stages of coxarthrosis, in patients requiring total hip arthroplasty (THA).

METHODS

77 consecutive patients without systemic disorders or prior hip surgery, scheduled for THA with 3 types of coxarthrosis: avascular necrosis (AVN), idiopathic, and dysplastic coxarthrosis were analysed. Patient's data: age, gender, side of the involvement, duration of the symptoms were recorded, and standard anteroposterior (AP) radiographic views of the pelvis were obtained. During THA procedure the acetabular labrum was harvested and examined histologically and immunohistochemically. The mean chondrocytes number and density were calculated using morphometric techniques.

RESULTS

In 77 analysed acetabular labra the following histological changes were found: heterogenic matrix, foci of granular matrix breakdown, pseudocysts, intralabral c alcifications, chondrocyte apoptosis, inflammatory reaction with lymphocytes infiltration and macrophages infiltration and vascular proliferation with 2 stages of maturation: endothelial cell formation and fully formed blood vessels. The average chondrocytes density was 478 cells in 1 mm2 and significantly decreased with age.

CONCLUSIONS

The acetabular labrum is an important part of the process of degeneration of the hip in osteoarthritis (OA). Vascular formation and cellular infiltration found in the damaged fibrocartilage may represent a labral response to degenerative changes.

Evaluation of the sealing function of the acetabular labrum: an in vitro biomechanical study

PURPOSE

To quantitatively evaluate the biomechanical sealing function of an intact labrum and the effect of labral-chondral separation, cerclage suture labral repair, vertical mattress suture repair and partial labrectomy on distraction load and hip joint centre (HJC) displacement.

METHODS

Eight fresh-frozen cadaveric hips were tested using a navigation system for intra-operative kinematic analysis. A six-axis load cell was used to measure the manually applied force when performing the tests: hip pivoting movement and distraction. The HJC displacement that occurred during the distraction test has been evaluated in correspondence of seven different values of applied force. During the pivoting motion, the maximum value of HJC displacement was evaluated. Five different conditions were tested: labrum intact, labral-chondral separation, vertical mattress suture repair, cerclage suture repair, and partial labrectomy.

RESULTS

With regard to HJC displacement using at fixed value of force, the paired sample t test underscored the statistically significant differences (p < 0.05) for each of the five tested conditions among themselves. Only the comparison of intact versus labral-chondral separation was not significantly different. During pivoting motion, a statistically significantly greater displacement was identified after labrectomy when compared with the cerclage suture repair (p = 0.03) and vertical mattress repair (p < 0.01) in medial-lateral direction. Along proximal-distal direction, a significant lower displacement after labrectomy was identified when compared to the cerclage suture repair (p = 0.03). Performing the pivoting motion at the extreme ranges of motion demonstrated a higher value of displacement after labrectomy when compared with all the previously tested conditions.

CONCLUSIONS

These results suggest that labral repair is important in the function of the hip and that the vertical mattress suture technique may be better than the cerclage suture repair.

Compression and Flip Test for Diagnosis of Unstable Acetabular Labral Tears Using a Peripheral Compartment Approach

Assessment of integrity of the acetabular labrum is generally done via the central compartment under distraction of the femoral head from the acetabulum. With the technique of raising the extra-articular and peripheral compartment first, there is a need for testing the stability and function of the labrum from the peripheral side in a nondistracted position of the joint. The authors report on the compression and flip test (i.e., the flip test) for the detection of unstable, intrasubstance tears of the labrum or unstable chondrolabral separations. The test can be performed by compressing the labrum with blunt instruments. We grade the labral conditions as follows: grade 0 for firm resistance and elasticity to palpation, grade 1+ as easily compressed by the probe, grade 2+ for eversion of the body of the labrum under compression), and grade 1 for ossified, hard resistance without any elasticity and compressibility. This test can be performed directly after accessing the peripheral compartment through a 2-portal technique without extensive capsular work.

The Role of Fluid Dynamics in Distributing Ankle Stresses in Anatomic and Injured States

BACKGROUND

In 1976, Ramsey and Hamilton published a landmark cadaveric study demonstrating a dramatic 42% decrease in tibiotalar contact area with only 1 mm of lateral talar shift. An increase in maximum principal stress of at least 72% is predicted based on these findings though the delayed development of arthritis in minimally misaligned ankles does not appear to be commensurate with the results found in dry cadaveric models. We hypothesized that synovial fluid could be a previously unrecognized factor that contributes significantly to stress distribution in the tibiotalar joint in anatomic and injured states.

METHODS

As it is not possible to directly measure contact stresses with and without fluid in a cadaveric model, finite element analysis (FEA) was employed for this study. FEA is a modeling technique used to calculate stresses in complex geometric structures by dividing them into small, simple components called elements. Four test configurations were investigated using a finite element model (FEM): baseline ankle alignment, 1 mm laterally translated talus and fibula, and the previous 2 bone orientations with fluid added. The FEM selected for this study was the Global Human Body Models Consortium-owned GHBMC model, M50 version 4.2, a model of an average-sized male (distributed by Elemance, LLC, Winston-Salem, NC). The ankle was loaded at the proximal tibia with a distributed load equal to the GHBMC body weight, and the maximum principal stress was computed.

RESULTS

All numerical simulations were stable and completed with no errors. In the baseline anatomic configuration, the addition of fluid between the tibia, fibula, and talus reduced the maximum principal stress computed in the distal tibia at maximum load from 31.3 N/mm² to 11.5 N/mm². Following 1 mm lateral translation of the talus and fibula, there was a modest 30% increase in the maximum stress in fluid cases. Qualitatively, translation created less high stress locations on the tibial plafond when fluid was incorporated into the model.

CONCLUSIONS

The findings in this study demonstrate a meaningful role for synovial fluid in distributing stresses within the ankle that has not been considered in historical dry cadaveric studies. The increase in maximum stress predicted by simulation of an ankle with fluid was less than half that projected by cadaveric data, indicating a protective effect of fluid in the injured state. The trends demonstrated by these simulations suggest that bony alignment and fluid in the ankle joint change loading patterns on the tibia and should be accounted for in future experiments.

CLINICAL RELEVANCE

Synovial fluid may play a protective role in ankle injuries, thus delaying the onset of arthritis. Reactive joint effusions may also function to additionally redistribute stresses with higher volumes of viscous fluid.

Acetabular labrum blood flow in developmental dysplasia of the hip: an intraoperative in vivo study using laser Doppler flowmetry

BACKGROUND

The vascular supply to the acetabular labrum is important in the treatment of labral lesions. However, in vivo blood flow measurements in the acetabular labrum have not been described in the literature. The purpose of this study was to examine this blood flow in vivo using laser Doppler flowmetry (LDF) in patients with acetabular dysplasia.

METHODS

Periacetabular osteotomy combined with arthroscopy was performed in 47 consecutive patients (three males, 44 females; mean age at surgery, 35.6 years; range, 15-60 years). In all patients, blood flow in the acetabular labrum was measured with LDF during arthroscopy. The acetabular labral lesions were categorized according to the modified Beck classification: detachment and full-thickness labral tears were assigned to the T group and normal labrum to the N group. Blood flow rates in the acetabular labrum were compared between the T and N groups. The associations between labral blood flow and the lateral center-edge angle (CEa) and patient age were also evaluated.

RESULTS

The T and N groups comprised 31 and 16 patients, respectively. The mean blood flow rate was 1.94 ± 0.41 ml/min/100 g in the T group and 1.94 ± 0.34 ml/min/100 g in the N group, with no significant difference between the groups (P = 0.884). No association was noted between blood flow and either the CEa or patient age (β = -0.018, P = 0.077 and β = -0.001, P = 0.770, respectively).

CONCLUSIONS

On LDF, blood flow in the acetabular labrum was present in all patients, regardless of the severity of acetabular labral tears, CEa, or age.

Reconstruction of Massive Posterior Nonrepairable Acetabular Labral Tears With Peroneus Brevis Tendon Allograft: Arthroscopy-Assisted Mini-Open Approach

Many of the described labral-reconstruction procedures are purely arthroscopic. This approach only allows segmentary reconstructions. For more extensive reconstructions, surgical dislocation of the hip still represents the more suitable approach. We present an arthroscopy-assisted procedure combined with an anterior mini-open approach, which could be considered for reconstruction of nonrepairable labral lesions located in the posterior aspect of the acetabulum and massive reconstructions in cases of global-pincer femoroacetabular impingement and protrusio acetabuli. Our technique saves the morbidity that might be related to the surgical dislocation of the hip and incorporates a peroneus brevis tendon allograft. This option may restore the anatomy and labral function without morbidity at the donor site, as well as remove graft length restrictions during massive reconstructions.

Safe Angle of Anchor Insertion for Labral Repair During Hip Arthroscopy

PURPOSE

To compare the use of the distal anterolateral accessory (DALA) portal with the anterolateral (AL) and midanterior (MA) portals during arthroscopic hip labral repair.

METHODS

Standard AL, MA, and DALA portals were created on 6 cadaveric hip specimens. Four 2.4-mm pins were placed in the acetabular rim to the depth of a standard anchor using a drill guide. Pins were placed in the 12 to 3 o'clock positions. The specimens then underwent computed tomographic scans with the pins left in place, and the distance from the pin to the articular surface was calculated at different depths of insertion.

RESULTS

In the anterior location, the average starting distance for the DALA pin was 2.05 mm and for the MA pin it was 2.51 mm from the articular surface (P = .29). Statistically significant differences between the DALA and MA pins were found at depths of 6 mm (P = .04) and 9 mm (P = .03). In the superior location, the average starting distance for the DALA pin was 2.40 mm and for the AL pin it was 2.62 mm from the articular surface (P = .34). Statistically significant differences between the DALA and AL pins were found at depths of 6 mm (P = .02), 9 mm (P = .01), 12 mm (P = .01), 15 mm (P = .04), and 18 mm (P = .04).

CONCLUSIONS

The DALA portal allows pins to be placed at a greater distance from the articular surface than the MA and AL portals when using a straight drill guide. This may decrease the incidence of intra-articular penetration during arthroscopic hip labral repair.

CLINICAL RELEVANCE

Intra-articular penetration of a drill bit or anchor is an iatrogenic complication that can occur during labral repair. By using the DALA portal instead of the AL and MA, the anchor can be safely placed on the acetabular rim and directly away from the articular surface, decreasing the chance for this complication.

Traumatic, Posterior Pediatric Hip Dislocations With Associated Posterior Labrum Osteochondral Avulsion: Recognizing the Acetabular "Fleck" Sign

BACKGROUND

Traumatic dislocation of the hip is uncommon in the pediatric population. Concentric reduction is usually achieved by closed means. Open reduction may be needed if there is femoral head fracture, incarcerated fragment, or incomplete reduction due to soft tissue entrapment. We present a series of 10 patients who sustained a posterior hip dislocation or subluxation with associated osteochondral avulsion of the posterior labrum. During surgery they were noted to have a labral injury pattern not previously recognized. Such treatment was dictated by postreduction advanced imaging, which revealed a consistent acetabular "fleck" sign indicative of this labral injury, which has not been previously described in literature.

METHODS

We performed a retrospective case review of patients with traumatic posterior hip dislocation/subluxation, treated operatively for a suspected associated labral tear and fractures.

RESULTS

Ten patients (2 girls and 8 boys) were identified. Average age was 12.7 years. Eight patients had postreduction computed tomography scans, which revealed a posterior acetabular wall "fleck" sign, suggestive of osteochondral injury. The small bony fragment was consistently displaced at least 2 to 3 mm in all patients with majority of the posterior wall remaining intact. Closed reduction was felt to be congruent in 7 of the 10 patients. All patients were treated operatively for exploration and stabilization of the suspected posterior labrum pathology and associated injuries using a surgical hip dislocation. A consistent pattern of labral pathology was seen in all patients, with disruption of the posterior labrum from the superior 12 o'clock attachment to detachment at the inferior 6 o'clock location. Reattachment of the osteochondral labral avulsion was performed with suture anchors along the posterior rim, and the associated femoral head fractures were also addressed with internal fixation. Two patients had inadequate follow-up and were excluded, the average follow-up for the remaining 8 patients was 9.8 months (range, 6 to 26 mo). There were no findings of avascular necrosis in any of the 8 patients.

CONCLUSIONS

Posterior hip dislocation in children may produce an acetabular "fleck" sign on advanced imaging, which in a stable, concentrically reduced hip has been treated without surgery in the past. Acetabular fleck sign may represent a near-complete avulsion of the posterior labrum as seen in our series. We recommend a high suspicion for this type of labral pathology and surgical repair when acetabular "fleck" sign is identified with hip subluxation or dislocation. Traumatic, posterior hip dislocations in young patients may be associated with significant labral pathology. Acetabular "fleck" sign on advanced imaging may predict such pathology.

LEVEL OF EVIDENCE

IV, retrospective study.

The influence of cartilage surface topography on fluid flow in the intra-articular gap

Self-lubrication of a diarthrodial joint is largely attributed to interstitial fluid pressurisation. However, the retention of synovial fluid within the intra-articular gap may also contribute to lubrication. Fluid flow in the intra-articular gap between two micro-rough cartilage surfaces was simulated with a three-dimensional numerical model. Representative surface roughness parameters were incorporated and their relative influence on gap flow resistance was quantified. Resistance changes with decreasing gap height were explored. Cartilage surface micro-topography improves the retention of viscous synovial fluid in the gap, through increased resistance to tangential flow. Local asperity contact greatly increases resistance through tortuosity of the flow path.

Biomechanical evaluation contribution of the acetabular labrum to hip stability

PURPOSE

Knowledge of the effect of hip pathologies on hip biomechanics is important to the understanding of the development of osteoarthritis, and the contribution of the labrum to hip joint stability has had limited study. The purpose of this study was to evaluate the effect of labral injury to stability of the femoral head in the acetabular socket.

METHODS

Ten cadaver hip specimens were tested using a robotic system under four different loading conditions: axial loading (80 N) along the femoral axis and axial loading (80 N) combined with either anterior, posterior or lateral loading (60 N). The hip states were examined were intact, with a 1.5 cm capsulotomy and with a 1 cm resection of the anterosuperior labrum.

RESULTS

At 30° of flexion, under axial load, the displacement of the hip with capsulotomy and labral resection (9.6 ± 2.5 mm) was significantly larger then the hip with capsulotomy alone (5.6 ± 4.1 mm, p = 0.005) and the intact hip (5.2 ± 3.8 mm, p = 0.005). Also, at 30° of flexion, the displacement under combined axial and anterior/posterior load was increased with capsulotomy and labral resection.

CONCLUSION

The acetabular labrum provides stability to the hip joint in response to a distraction force and combined distraction and translation forces. One centimetre of labral resection caused significant displacement ("wobbling" effect) of the femoral head within the acetabulum with normal range of motion. Successful labral repair could be crucial for restoration of the hip biomechanics and prevention of coxarthrosis.

Arthroscopic Technique for Acetabular Labral Reconstruction Using Iliotibial Band Autograft

The dynamic function of the acetabular labrum makes it an important structure for both hip stability and motion. Because of this, injuries to the labrum can cause significant dysfunction, leading to altered hip kinematics. Labral repair is the gold standard for symptomatic labral tears to keep as much labral tissue as possible; however, in cases where the labrum has been injured to such a degree that it is either deficient or repair is not possible, arthroscopic labral reconstruction is preferred. This article describes our preferred approach for reconstruction of the acetabular labrum using iliotibial band autograft.

Hip arthroscopy: a focus on the future

The indications for hip arthroscopy over the last decade have increased rapidly, driven by technical and technological advances aimed at hip joint preservation. This article reviews the current indications and supporting evidence for hip arthroscopy, explores some newer techniques/technologies and discusses the future directions in this rapidly evolving and expanding field.

The acetabular labrum

The acetabular labrum is a soft-tissue structure which lines the acetabular rim of the hip joint. Its role in hip joint biomechanics and joint health has been of particular interest over the past decade. In normal hip joint biomechanics, the labrum is crucial in retaining a layer of pressurised intra-articular fluid for joint lubrication and load support/distribution. Its seal around the femoral head is further regarded as a contributing to hip stability through its suction effect. The labrum itself is also important in increasing contact area thereby reducing contact stress. Given the labrum’s role in normal hip joint biomechanics, surgical techniques for managing labral damage are continuously evolving as our understanding of its anatomy and function continue to progress. The current paper aims to review the anatomy and biomechanical function of the labrum and how they are affected by differing surgical techniques.

Take home message: The acetabular labrum plays a critical role in hip function and maintaining and restoring its function during surgical intervention remain an essential goal.

Cite this article: Bone Joint J 2016;98-B:730–5.

Reconstruction of nonrepairable acetabular labral tears with allografts: mid-term results

BACKGROUND

Many labral tears are nonrepairable. For these cases, labral reconstruction procedures may be considered in order to restore the joint fluid seal and prolong hip longevity.

AIMS

The aim of this study was to describe the clinical and functional outcomes of a series of cases with nonrepairable labral tears that underwent labral reconstruction with tendon allografts. The hypothesis was that labral reconstruction would provide good clinical outcomes.

METHOD

A cohort of 20 patients with nonrepairable labral tears, which underwent to labral grafting mainly by means of arthroscopic assisted anterior mini-open approach, were included in this study. The study period was comprised between July 2008 and September 2013.

RESULTS

DCS-score resulted in 17 satisfactory results, whereas Nonarthritic Hip Score (NAHS) resulted in mean improvement of 39 points. 1 retrieved allograft demonstrated 8 weeks after implantation new whole revascularisation.

CONCLUSIONS

We concluded that labral reconstruction with tendon allograft provides relief of painful symptoms, and represents a reliable alternative for patients with nonrepairable labral tears that are not yet candidates for a joint replacement procedure.

Return to Elite Level of Play and Performance in Professional Golfers After Arthroscopic Hip Surgery

Background:

Hip conditions, such as femoroacetabular impingement and labral injury, can cause pain and limit the ability to play sports at a professional level.

Purpose:

To evaluate performance metrics of professional golfers prior to arthroscopic hip surgery and after surgery.

Study Design:

Case series; Level of evidence, 4.

Methods:

This study included professional golfers who underwent arthroscopic hip surgery. Primary outcome variables were greens in regulation and driving distance. Metrics were recorded for 2 years prior to arthroscopic hip surgery and 1, 2, and 5 years after arthroscopy.

Results:

A consecutive cohort of 20 male professional golfers (27 hips) from 2000 to 2011 underwent arthroscopic hip surgery by a single surgeon. All players were on the PGA Tour with a mean age of 38 years (range, 26-54 years). Eleven hips had labral repair and 16 had labral debridements. Four hips required microfracture of a chondral lesion. All players returned to play at a mean of 4.7 months (range, 1 month to 2 years). The mean number of years played after surgery was 5.72. There was no significant difference between preoperative and postoperative greens in regulation (P = .227). The mean distance per golf drive was significantly longer at 1 and 2 years postoperative compared with prior to surgery (P < .01), and driving distance at 5 years was also longer than preoperative (P = .008).

Conclusion:

Arthroscopic management of chondrolabral dysfunction due to femoroacetabular impingement in the professional golfer allowed the golfer to return to the same skill level prior to surgery. Mean driving distance was found to increase after arthroscopy, demonstrating not only a return but also an improvement in driving performance from prior level of play.

Arthroscopic Versus Open Treatment of Femoroacetabular Impingement: A Systematic Review of Medium- to Long-Term Outcomes

BACKGROUND

Surgical treatment of symptomatic femoroacetabular impingement (FAI) aims to improve symptoms and potentially delay initiation of hip osteoarthritis and prevent progression to end-stage hip osteoarthritis and possible total hip arthroplasty (THA). Hip arthroscopy and open surgical hip dislocations are the 2 most common surgical approaches used for this condition.

PURPOSE

To perform a comparative systematic review to determine whether there is a significant difference in clinical outcomes and progression to THA between hip arthroscopy and open surgical hip dislocation treatment for FAI at minimum medium-term follow-up.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

A systematic review of the MEDLINE database by use of the PubMed interface was performed. Minimum mean follow-up for included studies was set at 36 months. English-language studies with a minimum mean medium-term time frame evaluating outcome after arthroscopic or open treatment of FAI were included. Independent t tests, Kaplan-Meier survival analysis, and weighted mean pooled cohort statistics were performed.

RESULTS

A total of 16 studies met inclusion criteria. There were 9 open surgical hip dislocation studies and 7 hip arthroscopy studies. Open studies included 600 hips at a mean follow-up of 57.6 months (4.8 years; range, 6-144 months). Arthroscopic studies included 1484 hips at a mean follow-up of 50.8 months (4.2 years; range, 12-97 months). With THA as an outcome endpoint, there was an overall survival rate of 93% for open and 90.5% for arthroscopic procedures (P = .06). Advanced age and preexisting chondral injury were risk factors for progression to THA after both treatments. Direct comparison among disease-specific outcome instruments between the 2 procedures was limited by outcome measure heterogeneity; however, both treatments demonstrated good outcomes in their respective scoring systems. Notably, hip arthroscopy was associated with a higher general health-related quality of life (HRQoL) score on the 12-Item Short-Form Survey physical component score (P < .001).

CONCLUSION

Both hip arthroscopy and open surgical hip dislocation showed excellent and equivalent hip survival rates at medium-term follow-up with hip-specific outcome measures, demonstrating equivalence between groups. However, hip arthroscopy was shown to have superior results regarding general HRQoL in comparison to open treatment. An increased understanding of the natural history of FAI remains warranted, with further studies needed to assess long-term outcomes for patients with FAI.

Biomechanical Effects of Capsular Shift in the Treatment of Hip Microinstability: Creation and Testing of a Novel Hip Instability Model

BACKGROUND

A capsular shift procedure has been described for the treatment of hip instability; however, the biomechanical effects of such a shift are unknown.

PURPOSE

To create a cadaveric model of hip capsule laxity and evaluate the biomechanical effects of a capsular shift used to treat hip instability on this model.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eight cadaveric hips with an average age of 58.5 years were tested with a custom hip testing system in 6 conditions: intact, vented, instability, capsulotomy, side-to-side repair, and capsular shift. To create the hip model, the capsule was stretched in extension under 35 N·m of torque for 1 hour in neutral rotation. Measurements included internal and external rotation with 1.5 N·m of torque at 5 positions: 5° of extension and 0°, 15°, 30°, and 45° of flexion for each of the above conditions. The degree of maximum extension with 5 N·m of torque and the amount of femoral distraction with 40 N and 80 N of force were measured. Statistical analysis was performed by use of repeated-measures analysis of variance with Tukey post hoc analysis.

RESULTS

The instability state significantly increased internal rotation at all flexion angles and increased distraction compared with the intact state. The capsulotomy condition resulted in significantly increased external rotation and internal rotation at all positions, increased distraction, and maximum extension compared with the intact state. The side-to-side repair condition restored internal rotation back to the instability state but not to the intact state at 5° of extension and 0° of flexion. The capsular shift state significantly decreased internal rotation compared with the instability state at 5° of extension and 0° and 15° of flexion. The capsular shift and side-to-side repair conditions had similar effects on external rotation at all flexion-extension positions. The capsular shift state decreased distraction and maximum extension compared with the instability state, but the side-to-side repair state did not.

CONCLUSION

The hip capsular instability model was shown to have significantly greater total range of motion, external rotation, and extension compared with the intact condition. The greatest effects of capsular shift are seen with internal rotation, maximum extension, and distraction, with minimal effect on external rotation compared with the side-to side repair state.

CLINICAL RELEVANCE

The biomechanical effects of the capsular shift procedure indicate that it can be used to treat hip capsular laxity by decreasing extension and distraction with minimal effect on external rotation.

Open and Arthroscopic Treatment of Adult Hip Dysplasia: A Systematic Review

PURPOSE

To compare patient-reported outcome (PRO) and rates of conversion to total hip arthroplasty (THA) after hip arthroscopy, Bernese periacetabular osteotomy (PAO), and a combined approach for the management of patients with different grades of hip dysplasia.

METHODS

We searched MEDLINE and PubMed databases for articles published since 2000 using the following terms: (((("hip dysplasia") or "dysplastic") and "arthroscopy")) or ((("hip dysplasia") or "dysplastic") and "osteotomy"). Two authors independently reviewed the literature. Inclusion criteria were English language, relevance to hip dysplasia, surgical outcomes, and sample size of 10 patients or more. We excluded articles that were reviews or techniques; articles that included overlapping populations, patients with a mean age less than 18 years, patients with other hip conditions, patients with genetic or neuromuscular causes of hip dysplasia, and patients with Tonnis grade 2 or greater arthritis; articles on femoral osteotomy, and articles on previous surgical intervention, except hip arthroscopy. Articles were analyzed for PRO scores and rates of conversion to THA.

RESULTS

Ten of 759 articles reviewed met the inclusion and exclusion criteria. Of 834 hips treated for dysplasia with a mean age of 31 years, 114 were treated with arthroscopy alone, 703 were treated with PAO alone, and 17 were treated with both procedures. Mean follow-up was 3.2 years, 6.5 years, and 5.6 years, respectively. Conversion rates to THA were 4.8%, 12.0%, and 17.7%, respectively. In studies reporting pre- and postoperative PRO scores, all but one reported improvement.

CONCLUSIONS

The management of hip dysplasia may entail hip arthroscopy, PAO, or a combined approach. Arthroscopy has resulted in improved outcomes in borderline dysplastic cases (lateral center edge angle between 18° and 25°). PAO has primarily been used in true dysplasia with continued success. There were too few combined procedures of arthroscopy with PAO to reach a reliable conclusion in this subgroup.

Hip Joint Stresses Due to Cam-Type Femoroacetabular Impingement: A Systematic Review of Finite Element Simulations

Background

The cam deformity causes the anterosuperior femoral head to obstruct with the acetabulum, resulting in femoroacetabular impingement (FAI) and elevated risks of early osteoarthritis. Several finite element models have simulated adverse loading conditions due to cam FAI, to better understand the relationship between mechanical stresses and cartilage degeneration. Our purpose was to conduct a systematic review and examine the previous finite element models and simulations that examined hip joint stresses due to cam FAI.

Methods

The systematic review was conducted to identify those finite element studies of cam-type FAI. The review conformed to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and studies that reported hip joint contact pressures or stresses were included in the quantitative synthesis.

Results

Nine articles studied FAI morphologies using finite element methods and were included in the qualitative synthesis. Four articles specifically examined contact pressures and stresses due to cam FAI and were included in the quantitative synthesis. The studies demonstrated that cam FAI resulted in substantially elevated contact pressures (median = 10.4 MPa, range = 8.5–12.2 MPa) and von Mises stresses (median 15.5 MPa, range = 15.0–16.0 MPa) at the acetabular cartilage; and elevated maximum-shear stress on the bone (median = 15.2 MPa, range = 14.3–16.0 MPa), in comparison with control hips, during large amplitudes of hip motions. Many studies implemented or adapted idealized, ball-and-cup, parametric models to predict stresses, along with homogeneous bone material properties and in vivo instrumented prostheses loading data.

Conclusion

The formulation of a robust subject-specific FE model, to delineate the pathomechanisms of FAI, remains an ongoing challenge. The available literature provides clear insight into the estimated stresses due to the cam deformity and provides an assessment of its risks leading to early joint degeneration.

Clinical and Radiographic Predictors for Worsened Clinical Outcomes After Hip Arthroscopic Labral Preservation and Capsular Closure in Developmental Dysplasia of the Hip

BACKGROUND

Patients with developmental dysplasia of the hip (DDH) have a greater risk of acetabular labral tearing and joint instability, which predispose them to developing osteoarthritis. The arthroscopic management of DDH, however, remains controversial.

HYPOTHESIS

Specific clinical characteristics and radiographic parameters correlate with and predict a worsened clinical outcome after hip arthroscopic surgery for DDH.

STUDY DESIGN

Case control study; Level of evidence, 3.

METHODS

Of patients with DDH who underwent an arthroscopic procedure between March 2009 and June 2011, there were 28 hips in 28 patients (6 male and 22 female) that met the inclusion criteria. The mean patient age was 28.4 years. Clinical and radiographic follow-up evaluations up to a minimum of 2 years after surgery were performed for all patients. Failure of the procedure was defined as conversion to subsequent surgery or having a Tönnis osteoarthritis grade of 2 and modified Harris Hip Score (mHHS) that remained <85, and success was defined as patients who did not need subsequent surgery and had an mHHS >85. Univariate analysis and Cox hazard proportional analysis were performed on the 2 subpopulations.

RESULTS

There were 9 patients in the failure group (including 3 hips with T nnis grade 2) and 19 patients in the success group. In 22 of 28 patients, the mean mHHS significantly improved from 61.6 ± 18.8 (range, 12.0-85.0) preoperatively to 94.3 ± 7.0 (range, 73.7-100.0) at final follow-up, and the mean Non-Arthritic Hip Score (NAHS) improved from 56.2 ± 13.9 (range, 35.0-81.3) preoperatively to 92.7 ± 9.5 (range, 65.0-100.0) at final follow-up (P < .001, Wilcoxon signed-rank test). Univariate analysis showed that a broken Shenton line was significantly more prevalent in the failure group compared with the success group (8/9 [89%] vs 3/19 [16%] patients, respectively; P < .001). High-grade cartilage delamination (Multicenter Arthroscopy of the Hip Outcomes Research Network [MAHORN] grades 3-5) was significantly higher in the failure group than in the success group (8/9 [89%] vs 3/19 [16%] patients, respectively; P < .001). The median femoral neck-shaft (FNS) angle in the failure group was significantly higher than that in the success group (139° vs 134°, respectively; P = .01). Further, Cox hazard proportional analysis of the failure group showed that the predictors for a poor clinical outcome were the presence of a broken Shenton line, FNS angle >140°, center-edge (CE) angle <19°, body mass index (BMI) >23 kg/m(2), acetabular cartilage damage (MAHORN grades 3-5), and cartilage damage of the femoral head (International Cartilage Repair Society grades 2-4). The most important predictors for a poor clinical outcome at the time of surgery were a broken Shenton line and an FNS angle >140°.

CONCLUSION

Patients with a broken Shenton line, FNS angle >140°, CE angle <19°, or BMI >23 kg/m(2) at the time of surgery are not good candidates for the arthroscopic management of DDH.

Open Surgical Treatment for Femoroacetabular Impingement in Patients over Thirty Years: Two Years Follow-up Results

Purpose

We report short term results of open surgical treatment for symptomatic femoroacetabular impingement (FAI) in patients over the age of 30 years.

Materials and Methods

Between May 2011 and June 2012, thirteen FAI hips (11 patients) with hip pain persisting longer than 6 months were treated by either surgical hip dislocation (SHD) or anterior mini-open. They were followed up for longer than 2 years. The 11 patients included 7 females and 4 males with a mean age of 45 (range, 33-60) years. They were clinically evaluated for modified Harris hip score (MHHS) and University of California at Los Angeles (UCLA) activity level. Their lateral center-edge angle, acetabular index, and alpha angle were measured and compared.

Results

Acetabuloplasties were performed for seven cases. Femoral osteochondroplasty was performed for all thirteen cases. At minimum follow-up of two year (range, 24-29 months), all patients had substantial relief in preoperative pain with improvement in range of motion. The median MHHS was significantly (P<0.05) improved from 61 points preoperatively to 87 points at the last follow-up. The median UCLA activity level was 7 (range, 5-8) at last follow-up. Radiological indices improved. Two cases showed mild residual pain attributable to adhesion between capsule and reshaped femoral head-neck area.

Conclusion

Open surgical treatment of FAI was a reliable and effective treatment method in symptomatic FAIs for patients over the age of 30 years without advanced arthritic change of hip joint at short term follow-up.

Clinical and radiographical results of labral reconstruction

Treatment of femoroacetabular impingement (FAI) includes correction of underlying bony deformities. Labrum preservation is recommended whenever possible. In hips, where the labrum is missing or damaged beyond preservation, labral reconstruction is an option to restore labral seal. Between 2008 and 2011, 84 hips underwent treatment for FAI by means of a surgical hip dislocation. In 13 of these hips (11 patients), the severely damaged or missing labrum was reconstructed with ligamentum capitis femoris. Pre- and postoperative radiographic and clinical data were analysed with a mean follow-up of 38 months (range: 19–65 months). Clinical outcome was determined with Oxford hip score (OHS) and overall satisfaction, rest and load pain with a visual analogue scale (VAS; 0–100). Clinical outcome was compared with a control group where labral refixation was performed. Mean OHS improved significantly (P ≤ 0.001) from 29 (SD 8) to 44 (SD 4). Overall satisfaction with the hip increased significantly (P = 0.002) from 44 (SD 35) to 87 (SD 15). Mean VAS for rest pain decreased significantly (P = 0.0004) from 45 (SD 35) to 5 (SD 7) as well as for load pain (P = 0.0007) from 59 (SD 26) to 16 (SD 19). There were no significant differences between the two groups. Reconstruction of the acetabular labrum with ligamentum capitis femoris yields good clinical results. Technical superiority of open labral reconstruction may explain the unexpected, excellent outcome.

Acetabular Labral Base Repair Versus Circumferential Suture Repair: A Matched-Paired Comparison of Clinical Outcomes

PURPOSE

To determine whether an acetabular labral repair technique would be superior to another repair technique based on clinical outcomes measured by patient-reported outcome (PRO) scores.

METHODS

We identified 465 patients who underwent labral base repair or circumferential suture repair from February 2008 to February 2012. The type of repair performed was based on labral size and tear type. The 2 groups were pair matched for age within 5 years, sex, crossover sign within 15%, coxa profunda, Workers' Compensation status, and microfracture (femur, acetabulum, or none). Data were prospectively collected and retrospectively reviewed. PROs included a visual analog scale score and the modified Harris Hip Score, Non-Arthritic Hip Score, Hip Outcome Score-Activities of Daily Living, and Hip Outcome Score-Sports-Specific Subscale.

RESULTS

One hundred ten patients met the inclusion criteria for labral base repair and were pair matched on a 1:1 basis with 110 patients who underwent circumferential suture repair. The mean follow-up period was 30 months for both groups, with a range of 19.2 to 60 months for the labral base repair group and 19.2 to 67 months for the circumferential suture repair group. Radiographic data were similar between groups with respect to the lateral center-edge angle (P = .906), acetabular inclination (P = .329), anterior center-edge angle (P = .208), alpha angle (P = .387), and joint space width (P = .388). All preoperative PRO scores were statistically similar. Both groups showed significant improvements in all PROs. There were no statistical differences in postoperative PRO scores at latest follow-up (modified Harris Hip Score, P = .215; Hip Outcome Score-Activities of Daily Living, P = .839; Hip Outcome Score-Sports-Specific Subscale, P = .561; Non-Arthritic Hip Score, P = .333; visual analog scale score, P = .373; and satisfaction, P = .483). There were similar rates of revision (n = 10 for both groups) and conversion to arthroplasty (n = 2 for both groups).

CONCLUSIONS

On the basis of PRO scores at 2 years' follow-up, there is no difference in outcomes based on the type of labral repair performed.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.