Capsular Repair During Hip Arthroscopy Demonstrates Restoration of Axial Distraction Resistance in an in Vivo Intraoperative Testing Model

Hip Arthroscopy in Patients With Generalized Joint Hypermobility Yields Successful Outcomes: A Systematic Review

PURPOSE

To evaluate the outcomes of hip arthroscopy in patients with generalized joint hypermobility (GJH).

METHODS

A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses. An electronic record search was performed in PubMed, Web of Science, Cochrane Library, and Embase. A 2-stage title/abstract and full-text screening was performed using the following inclusion criteria: (1) observational studies, cohort studies, and randomized controlled trials; (2) describing more than 5 patients with a mean age over 18 years and GJH; (3) undergoing arthroscopy of the hip; (4) reporting patient-reported outcome measures (PROMs), return to sport, or complications/reoperations; and (5) published in English.

RESULTS

Of the 517 articles identified, 10 studies meeting all selection criteria were included. Included studies report significant improvements in a range of different functional and pain-based PROMs. Most patients (25.0%-97.0%) in each study achieved a clinically important improvement postoperatively in at least 1 PROM. No complications were described in any of the 4 studies reporting this metric. One study each found an association between GJH and an increased risk of postoperative deep gluteal syndrome and iliopsoas tendinitis. The rate of revision arthroscopy ranged from 0% to 11.4%, and only 2 patients in a single study of 11 hips required conversion to total hip arthroplasty. No statistically significant differences were reported between patients with and without GJH with respect to any of the described outcomes.

CONCLUSIONS

Patients with GJH may achieve good outcomes following hip arthroscopy with respect to PROMs, perioperative complications, reoperation, and return to sport. With effective labral repair and capsular closure, outcomes achieved in patients with GJH are comparable to those reported in patients without hypermobility.

LEVEL OF EVIDENCE

Level IV, systematic review of level III to IV studies.

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

Background

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

Purpose

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

Study Design

Controlled laboratory study.

Methods

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

Results

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

Conclusion

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

Clinical Relevance

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

Magnetic Resonance Imaging and Magnetic Resonance Arthrography Are Both Reliable and Similar When Measuring Hip Capsule Thickness in Patients With Femoroacetabular Impingement Syndrome

Purpose

To propose an accurate method of measuring hip capsular thickness in patients with femoroacetabular impingement syndrome and to compare the reliability of these measurements between magnetic resonance imaging (MRI) and magnetic resonance arthrography (MRA).

Methods

A previously established database of patients with femoroacetabular impingement syndrome (FAIS) was used to identify candidates with preoperative MRI or MRA from November 2018 to June 2021. Two reviewers independently examined preoperative imaging for 85 patients. Capsular thickness was measured in 12 standardized locations. Intraclass correlation coefficients (ICCs) were calculated using an absolute-agreement, 2-way random-effects model. Using the same method, 30 patients were randomly selected for repeat measurements by 1 reviewer following a washout period. Ten additional patients with preoperative MRI and MRA of the same hip were identified to compare measurements between modalities using paired samples t test.

Results

ICCs for measurements on MRIs and MRAs using these proposed measurements to compare inter-rater reliability were 0.981 and 0.985. ICCs calculated using measurements by a single reviewer following a washout period for intrarater reliability were 0.998 and 0.991. When comparing MRI and MRA measurements in the same patient, t test for all pooled measurements found no difference between modality (P = .283), and breakdown of measurements by quadrant found no difference in measurements (P > .05), with the exception of the inferior aspect of the capsule on coronal sequences (P = .023).

Conclusions

In patients with FAIS, both MRI and MRA have excellent reliability for quantifying hip capsular thickness. A difference in capsular thickness was found only when comparing MRI and MRA on inferior coronal aspects of the hip capsule, indicating interchangeability of these imaging modalities when measuring the clinically important aspects of the hip capsule.

Level of Evidence

Level IV, diagnostic case series.

Relationship Between Hip Capsular Thickness and Instability After Previous Hip Arthroscopic Surgery: A Matched-Cohort Analysis

Background

Thinner anterior hip capsules are associated with hip laxity, but there is little known about the impact of capsular thickness on the development of instability after primary hip arthroscopic surgery.

Purpose

To investigate the relationship between hip capsular thickness as measured on preoperative magnetic resonance imaging (MRI) and the development of hip instability after hip arthroscopic surgery for femoroacetabular impingement.

Study Design

Case-control study; Level of evidence, 3.

Methods

We reviewed revision hip arthroscopic procedures performed between January 1, 2019, and May 1, 2021, at a single institution. Inclusion criteria were preoperative MRI/magnetic resonance arthrography, completion of the study traction protocol, and asymmetric distraction between the hips of ≥3 mm on examination under anesthesia. A comparison group of patients treated for femoroacetabular impingement with primary hip arthroscopic surgery who did not develop capsular instability were matched 1:1 to the patients with instability. Superolateral hip capsular thickness was measured on MRI before index surgery. Analysis was conducted using independent-samples t tests and multivariable linear regression.

Results

A total of 44 patients were included, with 22 patients each in the instability and no-instability groups. The mean capsular thickness was lower in the patients with hip instability than in those without (1.9 ± 0.6 vs 3.4 ± 1.1 mm, respectively; P < .001). Decreased capsular thickness was significantly associated with hips with instability versus no-instability (β = -1.468 [95% CI, -2.049 to -0.887]; P < .001).

Conclusion

Thinner preoperative hip capsules in the region of the iliofemoral ligament were seen in patients who subsequently underwent revision arthroscopic surgery for hip instability compared to patients who underwent primary hip arthroscopic surgery without subsequent revision. Patients at a higher risk for the development of postoperative hip instability had a superolateral hip capsular thickness of <2 mm.

Capsular Management During Hip Arthroscopy

PURPOSE OF REVIEW

Hip arthroscopy is widely used for the management of intra-articular pathology and there has been growing interest in strategies for management of the hip capsule during surgery. The hip capsule is an essential structure that provides stability to the joint and it is necessarily violated during procedures that address intra-articular pathology. This article reviews different approaches to capsular management during hip arthroscopy including anatomical considerations for capsulotomy, techniques, clinical outcomes, and the role of routine capsular repair. This article also reviews the concept of hip microinstability and its potential impact on capsular management options as well as iatrogenic complications that can occur as a result of poor capsular management.

RECENT FINDINGS

Current research highlights the key functional role of the hip capsule and the importance of preserving its anatomy during surgery. Capsulotomies that involve less tissue violation (periportal and puncture-type approaches) do not appear to require routine capsular repair to achieve good outcomes. Many studies have investigated the role of capsular repair following more extensive capsulotomy types (interportal and T-type), with most authors reporting superior outcomes with routine capsular repair. Strategies for capsular management during hip arthroscopy range from conservative capsulotomy techniques aimed to minimize capsular violation to more extensive capsulotomies with routine capsule closure, all of which have good short- to mid-term outcomes. There is a growing trend towards decreasing iatrogenic capsular tissue injury when possible and fully repairing the capsule when larger capsulotomies are utilized. Future research may reveal that patients with microinstability may require a more specific approach to capsular management.

Superior outcomes after arthroscopic treatment of femoroacetabular impingement and labral tears with closed versus open capsule

PURPOSE

The purpose of the study was the clinical evaluation of the capsular management with arthroscopic treatment of femoroacetabular impingement and labral tears by comparing the functional outcomes of closed versus open capsule.

METHODS

Patients with a median age of 38 years (18-55), clinical and radiological features of FAI and/or labral tear, and non-arthritic non-dysplastic hips were selected for arthroscopic treatment. Capsulotomy was performed primarily as an interportal section, then a distal extension preserving the zona orbicularis was added. The study compared two matched groups: patients with open capsule versus patients with closed capsule. Clinical outcomes were assessed by Non-Arthritic Hip Score, hip outcome scores of daily living activities and sports-specific scales. Scores were collected preoperatively and 6 months, 2 years and 5 years postoperatively. Rate of revision arthroscopy and conversion to total hip arthroplasty were used for comparing groups. Minimal clinically important differences were calculated for both groups.

RESULTS

The study included 42 patients in the OC group and 44 patients in the CC group. Significant improvement of postoperative PROMs was recorded in both groups compared to preoperative scores. CC group significantly improved more than the OC group based on NAHS, HOS-ADL and HOS-SSS over all check points except for NAHS and HOS-ADL at 6 months, which were statistically non-significant. A non-significant difference was observed in the percentage of patients who met the MCID for all reported outcome scores at 5 years in both groups. The rate of reoperation was similar in both groups, but with different indications.

CONCLUSION

Arthroscopic treatment of FAI and labral repair with complete closure of the hip capsule led to significantly improved functional outcomes after 5 years follow-up compared with open capsule. Closed capsule can provide greater improvement in the sports-specific outcomes at early follow-up. Controlled capsulotomy limited by zona orbicularis did not produce instability at any postoperative stage. Similar proportions of patients achieved minimal clinically important difference, and similar rates of reoperation were reported in both groups.

LEVEL OF EVIDENCE

III.

Use and Effectiveness of Physical Therapy After Hip Arthroscopy for Femoroacetabular Impingement

BACKGROUND

Limited literature exists regarding how postoperative physical therapy (PT) may affect outcomes in patients with femoroacetabular impingement syndrome (FAIS) undergoing hip arthroscopy. Additionally, it is unknown how PT measures relate to traditional orthopaedic patient-reported outcomes (PROs).

PURPOSE

To evaluate how the duration of PT may correlate with outcomes in patients with FAIS using both the Lower Extremity Functional Scale (LEFS) and standard orthopaedic PRO measures.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients from a single institution who underwent primary hip arthroscopy for FAIS between 2013 and 2016 were identified. Patients with a minimum 2-year follow-up and fully documented PT notes were included and stratified into 3 cohorts based on timing of PT discharge: 0 to 3 months, 3 to 6 months, and 6 to 12 months. Predictive regression models were developed to analyze the rate of improvement (ROI) in LEFS score as it relates to (1) postoperative day (POD) and (2) postoperative PT session number. Two-year PROs were collected, correlated with LEFS scores, and compared among cohorts.

RESULTS

A total of 95 patients were included (mean ± SD age, 34.6 ± 11.7 years; range, 14-55 years). Mean LEFS scores increased significantly from the initial score at 6 weeks, 3 months, and the time of PT discharge (P < .01 for all). The predicted ROI in LEFS score was 3.39% per PT session for sessions 0 to 13, 1.43% for sessions 14 to 27, and 0.37% for sessions 28 to 40. Patients who underwent 3 to 6 months of PT had significantly better Hip Outcome Score (HOS) relative to the 0- to 3-month cohort and significantly better visual analog scale (VAS) scores for satisfaction relative to the 6- to 12-month cohort. The predicted ROI in LEFS score was 0.96% per day from POD 0 to 45, 0.22% from POD 46 to 139, and 0.03% after POD 139. Moderate correlations were seen between LEFS score at the time of discharge and all 2-year PROs as follows: HOS Activities of Daily Living subscale (r = 0.488), HOS Sports-Specific subscale (r = 0.500), modified Harris Hip Score (r = 0.465), 12-item International Hip Outcome Tool (r = 0.494), VAS pain score (r = -0.346), and VAS satisfaction score (r = 0.459).

CONCLUSION

Patients undergoing hip arthroscopy for FAIS derived substantial benefit from each PT visit during their first 13 PT sessions and then a smaller, yet still meaningful benefit from sessions 13 through 27. After session 40, or approximately 4.5 to 5 months, patients no longer benefited from additional PT sessions. Based on PRO scores, patients discharged from PT between 3 and 6 months had the best 2-year outcomes. LEFS score had moderate correlation with orthopaedic PRO scores.

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

Purpose

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

Methods

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

Results

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

Conclusions

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

Level of Evidence

Level IV, case series.

Patients Maintain Clinically Significant Outcomes at 5-Year Follow-Up after Hip Arthroscopy for Femoroacetabular Impingement Syndrome: A Systematic Review

PURPOSE

To assess 5-year outcomes and survival rate of hip arthroscopy (HA) for femoroacetabular impingement syndrome (FAIS) and to determine achievement rates of clinically significant outcomes.

METHODS

Three databases were searched around the following terms: hip arthroscopy, FAIS, and 5-year follow-up. Articles available in English, presenting original data, and reporting minimum 5-year follow-up after primary HA using either patient reported outcomes (PROs) or conversion to total hip arthroplasty (THA) and/or revision surgery were included. Quality assessment was completed using MINORS assessment, and relative agreement was calculated using Cohen's kappa.

RESULTS

Fifteen articles were included. MINORS assessment ranged from 11-22, with excellent (k=0.842) inter-rater reliability between reviewers. 2080 patients were included at a follow-up range of 60.0-84 months. Labral repair was the most commonly performed procedure (range: 8.0%-100%). All studies included PROs and all reported statistically significant improvement (p<0.05) at the 5-year timepoint. The most frequent PRO reported was modified Harris Hip Score (mHHS) (n=8). Nine studies reported on clinically significant outcome achievement, with mHHS being the most common (n=8). The rate of achieving minimal clinically important difference (MCID) ranged from 64-100%, patient-acceptable symptomatic state (PASS) ranged from 45-87.4%, and substantial clinical benefit (SCB) ranged from 35.3-66%. Conversion to THA and revision surgery varied across studies, with ranges of 0.0%-17.9% (duration: 28.8-87.1 months) and 1.3%-26.7% (duration: 14.8-83.7 months), respectively. The most common definition of failure was conversion to THA or revision (n=7). Increased age (n=5) and greater joint degeneration (n=4) were the most common predictors of clinical failure.

CONCLUSIONS

Patients undergoing primary hip arthroscopy for FAIS demonstrate significant improvement at 5-year follow-up, with maintained rates of achievement of MCID, PASS, and SCB. Survival rate of HA at 5-years is overall high, with ranges of 0.0-17.9% and 1.3-26.7% % conversion to THA or revision surgery, respectively. Across studies, increased age and greater joint degeneration were the most common cited predictors of clinical failure.

Patients With Simple Posterior Hip Dislocations Have Higher Rates of Hip Dysplasia and Borderline Dysplasia

OBJECTIVES

To determine if patients suffering simple, posterior hip dislocations are more likely to display dysplastic characteristics of their acetabulum as compared with those suffering fracture dislocations.

DESIGN

Retrospective cohort study.

SETTING

Level 1 trauma center.

PATIENTS/PARTICIPANTS

Eighty-six patients suffering posterior, native hip dislocations over a 5-year period.

MAIN OUTCOME MEASUREMENT

The primary outcome was measurement of the lateral center edge angle (LCEA), acetabular index (AI), acetabular version, and femoro-epiphyseal acetabular roof (FEAR) index.

RESULTS

Eighteen patients (20.9%) sustained simple dislocations, whereas 68 patients (79.1%) suffered fracture dislocations. Patients with simple dislocations had decreased LCEA (25.7 vs. 34.3; P < 0.001), increased AI (7.4 vs. 5.8; P = 0.019), and decreased acetabular anteversion (14.02 vs. 18.45; P = 0.011). Additionally, patients with simple dislocations had higher rates of dysplasia and borderline dysplasia (61.1% vs. 7.3%; P < 0.001). Patients with fracture dislocations had higher rates of concomitant injuries (60.9% vs. 29.4%; P = 0.039) and higher injury severity scores (8.1 vs. 12.3; P = 0.022).

CONCLUSION

Patients who sustain simple hip dislocations are more likely to have undercoverage of the femoral head by the acetabulum as compared with patients suffering fracture dislocations. In addition, the simple dislocation group had a lower ISS and fewer concomitant injuries, which likely relates to a lower energy required for dislocation in the setting of lesser bony constraint. Surgeons treating these complicated injuries should consider measurements of LCE and AI when counseling patients on treatment strategies.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Female Patients and Decreased Hip Capsular Thickness on Magnetic Resonance Imaging Associated With Increased Axial Distraction Distance on Examination Under Anesthesia: An In Vivo Study

PURPOSE

To investigate the relation of hip capsular thickness as measured on preoperative magnetic resonance imaging (MRI) and intraoperative hip joint axial distraction distance on an examination under anesthesia.

METHODS

A retrospective review of primary arthroscopic hip procedures performed between November 2018 and June 2021 was conducted. The inclusion criteria included a diagnosis of femoroacetabular impingement syndrome and preoperative radiographic imaging and MRI. Fluoroscopic images were obtained at 0 lb and 100 lb of axial traction force. Total distraction distance was calculated by comparing the initial joint space with the total joint space at 100 lb. Hip capsular thickness was measured on MRI. Analysis was conducted using multiple linear regression, independent-samples t tests, and Mann-Whitney U tests.

RESULTS

Eighty patients were included. Bivariable regression showed an association between an increased distraction distance and female sex (β = 4.303, R = 0.561, P < .001), as well as decreased anterior axial (β = -1.291, R = 0.365, P < .001) and superior coronal (β = -1.433, R = 0.501, P < .001) capsular thickness. Multivariable regression (R = 0.645) showed an association between an increased distraction distance and female sex (β = 3.175, P < .001), as well as decreased superior coronal capsular thickness (β = -0.764, P = .022). Independent-samples t tests showed that female patients had significantly decreased superior coronal capsular thickness (2.92 ± 1.14 mm vs 3.99 ± 1.15 mm, P < .001).

CONCLUSIONS

Female sex and decreased hip capsular thickness in the superior aspect of the coronal plane on magnetic resonance scans were found to be predictors of increased hip joint axial distraction distance on examination under anesthesia prior to hip arthroscopy, with anterior axial capsular thickness being a moderate predictor. Poor predictors of distraction distance were posterior axial and inferior coronal capsular thickness, age, body mass index, and lateral center-edge angle. Female patients were also found to have thinner hip capsules in the superior region, which may explain the association between female patients and increased distraction. These findings further characterize the relation between capsular thickness and hip laxity.

LEVEL OF EVIDENCE

Level IV, case series.

Comparable Torque to Failure Using the Simple Stich Versus the Figure-of-Eight Configuration for Hip Capsular Closure Following an Interportal Capsulotomy: A Cadaveric Study

PURPOSE

To measure and compare the torque to failure and stiffness of the capsular repair construct consisting of four-suture simple stitches to a two-figure of eight stitches repair construct in external rotation following an interportal capsulotomy.

METHODS

Six pairs of fresh-frozen cadaveric hemipelves were divided into two capsular repair groups. All hips underwent a 40-mm interportal capsulotomy from the 12 o'clock position to the 3 o'clock position. Capsular closure was performed using either the two stitches in a figure of eight or with four simple stitches. Afterward, each hemipelvis was securely fixed to the frame of a mechanical testing system with the hip in 10° of extension and externally rotated to failure. Significance was set at P < .05.

RESULTS

The average failure torque was 86.2 ± 18.9 N·m and 81.5 ± 8.9 N·m (P = .57) for the two stitches in a figure of eight and the four simple stitches, respectively. Failure stiffness was also not statistically different between groups and both capsular closure techniques failed at similar degrees of rotation (P = .65).

CONCLUSION

Hip capsular repair using either the four simple stitch or two-figure of eight configurations following interportal capsulotomy demonstrated comparable failure torques and similar stiffness in a cadaveric model.

CLINICAL RELEVANCE

Adequate and comprehensive capsular management in hip arthroscopy is critical. Capsular repair following capsulotomy in femoroacetabular impingement surgery has been associated with higher patient-reported outcomes when compared to capsulotomy without repair. Therefore, determining which capsular closure construct provides the higher failure torque is important.