Changes in Hip Capsule Morphology after Arthroscopic Treatment for Femoroacetabular Impingement Syndrome with Periportal Capsulotomy are Correlated With Improvements in Patient-Reported Outcomes

Editorial Commentary: Prolonged Joint Effusion After Hip Arthroscopy May Be Associated With Persistent Symptoms

Research to investigate causes for continued symptoms in patients who undergo hip arthroscopic treatment is an opportunity to improve outcomes. A disconcertingly large number of patients (47%-66%) show a joint effusion/synovitis on magnetic resonance imaging at 6 to 12 months after hip arthroscopy for femoroacetabular impingement syndrome, and a recent study shows that this is associated with inferior 2-year clinical outcomes compared to patients without effusions. Perhaps the effusions are associated with comorbid structural abnormalities such as cartilage degeneration, capsule defect, labral reinjury, adhesions, or microinstability/hyperlaxity. In theory, interventions to treat the effusion, such as intra-articular injections or anti-inflammatory medications (which also prophylax against heterotopic ossification), will produce sustained clinical improvement.

Editorial Commentary: Capsular Management During Hip Arthroscopy Is Recommended, But a Limited Capsulotomy in Male Patients May Heal Without Closure

The hip capsule consists of the iliofemoral, ischiofemoral, and pubfemoral ligaments. The iliofemoral ligament is an important part of the anterior hip capsule that functions to stabilize the joint but is commonly incised in order to obtain access during hip arthroscopy, as described in techniques such as interportal, T, puncture, and periportal capsulotomy. For the most commonly used interportal capsulotomy, recent literature has advocated for closure of the capsule at the end of the surgery to avoid iatrogenic instability or microinstability. Systematic reviews and cohort studies have reported significantly better patient-reported outcomes after hip arthroscopy for femoroacetabular impingement syndrome with capsule closure compared to without capsule closure. However, recent high-level evidence from a randomized controlled trial demonstrated that in a predominantly male cohort there was no difference in patient-reported outcomes improvements or complications between patients undergoing hip arthroscopy for femoroacetabular impingement syndrome through an interportal capsulotomy who were randomized to receive capsule closure versus no capsule closure. Of note, male patients have inherently tighter and more stable joints than female patients and therefore are at lower risk for postoperative instability or microinstability from an interportal capsulotomy that does not properly heal. Also, if the capsule is not violated below the 3-o'clock position (for a right hip, or 9 o'clock for a left hip), there may be less risk to destabilizing the hip joint. A limited interportal capsulotomy in male patients could lead to healing in an unrepaired state.

Is hip capsule morphology associated with hip pain in patients without another structural correlate?

OBJECTIVE

The goals of this study were (i) to assess the association between hip capsule morphology and pain in patients without any other MRI abnormalities that would correlate with pain and (ii) to investigate whether hip capsule morphology in hip pain patients is different from that of controls.

METHODS

In this study, 76 adults with hip pain who did not show any structural abnormalities on MRI and 46 asymptomatic volunteers were included. Manual segmentation of the anterior and posterior hip capsules was performed. Total and mean anterior hip capsule area, posterior capsule area, anterior-to-posterior capsule area ratio, and medial-to-lateral area ratio in the anterior capsule were quantified. Differences between the pain and control groups were evaluated using logistic regression models.

RESULTS

Patients with hip pain showed a significantly lower anterior-to-posterior area ratio as compared with the control group (p = 0.002). The pain group's posterior hip capsule area was significantly larger than that of controls (p = 0.001). Additionally, the ratio between the medial and lateral sections of the anterior capsule was significantly lower in the pain group (p = 0.004).

CONCLUSIONS

Patients with hip pain are more likely to have thicker posterior capsules and a lower ratio of the anterior-to-posterior capsule area and thinner medial anterior capsules with a lower ratio of the medial-to-lateral anterior hip capsule compartment, compared with controls.

CLINICAL RELEVANCE STATEMENT

During MRI evaluations of patients with hip pain, morphology of the hip capsule should be assessed. This study aims to be a foundation for future analyses to identify thresholds distinguishing normal from abnormal hip capsule measurements.

KEY POINTS

• Even with modern image modalities such as MRI, one of the biggest challenges in handling hip pain patients is finding a structural link for their pain. • Hip capsule morphologies that correlated with hip pain showed a larger posterior hip capsule area and a lower anterior-to-posterior capsule area ratio, as well as a smaller medial anterior capsule area with a lower medial-to-lateral anterior hip capsule ratio. • The hip capsule morphology is correlated with hip pain in patients who do not show other morphology abnormalities in MRI and should get more attention in clinical practice.

Eighty-One Percent of Unrepaired Interportal Capsulotomies Showed Healed Capsules on Magnetic Resonance Imaging 5 Years After Primary Hip Arthroscopy

Purpose

To evaluate whether unrepaired interportal capsulotomy presents with capsular defect on magnetic resonance imaging (MRI) 5 years after primary hip arthroscopy and to determine its effect on functional results and findings of osteoarthritis on radiographs or MRI scans.

Methods

Patients with femoroacetabular impingement (without arthritis or dysplasia) were retrospectively reviewed after arthroscopic labral repair or debridement and femoroplasty through interportal capsulotomy without closure. Patients were assessed preoperatively and at a minimum of 5 years postoperatively using patient-reported outcomes (Hip Outcome Score-Activities of Daily Living scale, modified Harris Hip Score, and visual analog scale pain score), radiographic measures, and MRI scans.

Results

Forty patients (42 hips) were deemed eligible for the study and were evaluated. Of the hips, 81% had healed capsules, whereas 8 (19%) had capsular defects on the latest MRI scan. There were 3 hips with subchondral edema in the defect group compared with 1 in the healed-capsule group (P = .01) on the latest MRI scan, which was not present on preoperative MRI (still positive on multivariate analysis when the preoperative alpha angle was also taken into consideration). Functional results did not differ between the groups (P > .05).

Conclusions

In this study, 81% of interportal capsulotomies healed without repair at 5 years after primary hip arthroscopy.

Clinical Relevance

Understanding the prevalence and implications of unhealed capsulotomies could encourage surgeons to be meticulous in capsular closure.

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.

Predicting Outcomes in Hip Arthroscopy for Femoroacetabular Impingement Syndrome

PURPOSE OF REVIEW

Arthroscopic treatment of femoroacetabular impingement syndrome (FAIS) continues to rise in incidence, and thus there is an increased focus on factors that predict patient outcomes. The factors that impact the outcomes of arthroscopic FAIS treatment are complex. The purpose of this review is to outline the current literature concerning predictors of patient outcomes for arthroscopic treatment of FAIS.

RECENT FINDINGS

Multiple studies have shown that various patient demographics, joint parameters, and surgical techniques are all correlated with postoperative outcomes after arthroscopic FAIS surgery, as measured by both validated patient-reported outcome (PRO) scores and rates of revision surgery including hip arthroplasty. To accurately predict patient outcomes for arthroscopic FAIS surgery, consideration should be directed toward preoperative patient-specific factors and intraoperative technical factors. The future of accurately selecting patient predictors for outcomes will only improve with increased data, improved techniques, and technological advancement.

Ultrasound had high accuracy in measuring hip joint capsule thickness

BACKGROUND

The hip joint capsule is an essential component of hip joint function and stability, and its thickness is closely associated with certain medical conditions, surgical outcomes, and rehabilitation treatments. Currently, in clinical practice, hip joint capsule thickness is predominantly measured using magnetic resonance imaging (MRI), with limited utilization of ultrasound examinations for this purpose.

METHODS

We retrospectively evaluated patients who visited our Sports Medicine Department between February 2017 and March 2023 and underwent both hip joint MRI and ultrasound imaging on the same side. All patients had undergone preoperative hip joint MRI and ultrasound examinations, with the time gap between the two examinations not exceeding three months. Measurements of hip joint capsule thickness were taken on both MRI and ultrasound images for the same patients to analyze their consistency. Additionally, we measured the alpha angle, lateral center-edge angle, acetabular anteversion angle, and femoral anteversion angle of the patients' hip joints and analyzed their correlation with hip joint capsule thickness measure by ultrasound.

RESULTS

A total of 307 patients were included in this study, with hip joint capsule thickness measured by MRI and ultrasound being 5.0 ± 1.2 mm and 5.0 ± 1.5 mm, respectively. The Bland-Altman analysis demonstrates good agreement or consistency. The paired t-test resulted in a p-value of 0.708, indicating no significant statistical difference between the two methods. The correlation analysis between acetabular anteversion angle and ultrasound-measured capsule thickness yielded a p-value of 0.043, indicating acetabular anteversion angle and capsular thickness may have negative correlation.

CONCLUSIONS

The measurements of joint capsule thickness obtained through ultrasound and MRI showed good consistency, suggesting that ultrasound can be used in clinical practice as a replacement for MRI in measuring hip joint capsule thickness. There was a significant correlation between acetabular anteversion angle and hip joint capsule thickness, indicating potential for further research in this area.

Comparable Injury to the Indirect Head of the Rectus Femoris During Interportal and Periportal Capsulotomy: A Cadaveric Study

Background

There is concern for maintaining the integrity of the reflected head of the rectus femoris during arthroscopic hip joint access. Because of the proximity to the indirect head of the rectus femoris (IHRF), capsulotomy technique and capsular closure during routine hip arthroscopy may play a role in postoperative tendinitis.

Purpose

To quantify the extent of injury sustained to the IHRF during interportal versus periportal capsulotomy for routine arthroscopic hip joint access.

Study Design

Controlled laboratory study.

Methods

A cadaveric study was conducted using 20 fresh-frozen cadaveric hips, in which hip joint access through a periportal capsulotomy (n = 10) or interportal capsulotomy (n = 10) was performed. Capsular closure followed by a layered dissection to the capsuloligamentous complex of the hip joint was then performed to localize the IHRF. Suture proximity to the tendon, tendon disruption, and the IHRF footprint was documented to the nearest 0.01 mm using digital calipers. Statistical analysis was performed using unpaired Student t tests.

Results

The mean capsulotomy length for the interportal specimens was 19.27 ± 3.25 mm, and the mean medial and lateral capsulotomy length for the periportal specimens was 4.47 ± 1.60 and 4.26 ± 0.89 mm, respectively. There was violation of the tendon in 3 of 10 interportal specimens and 4 of 10 periportal specimens. There was no significant difference in the closest suture measured to the IHRF for specimens with versus without tendon violation, for either interportal or periportal capsulotomy.

Conclusion

We found comparable outcomes with regard to violation of the IHRF between interportal and periportal capsulotomy, with no significant difference in suture proximity to the IHRF in specimens with or without tendon violation. There remains no consensus on the ideal method by which to avoid iatrogenic damage to the IHRF.

Clinical Relevance

Our findings provide insight that may lead to future advances in surgical care, such that protection of the tendon during routine hip arthroscopy may allow for improved postoperative rehabilitation and strength.

Editorial Commentary: Interportal Capsulotomy for Hip Arthroscopy in Patients With Borderline Hip Dysplasia May Result in Inferior Outcomes: Periportal Capsulotomy May Reduce Hip Capsular Damage

Management of the hip capsule remains an ongoing discussion in the field of hip arthroscopy. Interportal and T-capsulotomies remain the most common approaches to gain access to the hip during surgery, and biomechanical and clinical research supports repair of these types of capsulotomies. Less is known, however, about the quality of the tissue that heals at these repair sites during the postoperative period, particularly in the setting of patients with borderline hip dysplasia. The capsular tissue provides important joint stability to these patients, and disruption to the capsule can result in significant functional impairments. There is also an association between borderline hip dysplasia and joint hypermobility, which increases the risk of insufficient healing after capsular repair. Patients with borderline hip dysplasia show poor capsular healing after arthroscopy followed by interportal hip capsule repair, and incomplete healing results in inferior patient-reported outcomes. Periportal capsulotomy may limit capsular violation and improve outcomes.

Capsular Repair is Associated with Lower Revision Rates Yet Similar Clinical Outcomes and Arthroplasty Conversion 5-Years after Hip Arthroscopy: A Systematic Review

PURPOSE

The purpose of this study was to perform a systematic review of studies reporting on minimum 5-year outcomes of patients undergoing primary hip arthroscopy (HA) for femoroacetabular impingement syndrome (FAIS) to determine whether capsular management influences patient-reported outcomes (PROs), rates of clinically significant outcome, and rates of revision surgery or conversion to total hip arthroplasty (THA).

METHODS

PubMed, Scopus, and Google Scholar were searched around the terms hip arthroscopy, FAIS, five-year follow-up, and capsule management. Articles available in English, presenting original data, and reporting minimum 5-year follow-up after HA using either PROs or conversion to THA and/or revision surgery were included. Quality assessment was completed using MINORS assessment. Articles were stratified into unrepaired and repaired capsule cohorts (excluding periportal capsulotomy techniques).

RESULTS

Eight articles were included. MINORS assessment ranged from 11-22, with excellent (k=0.842) inter-rater reliability. Populations without capsular repair were identified in four studies including a total of 387 patients, at an age of 33.1-38.0 years and follow-up range of 60.0-77 months. Populations with capsular repair were identified in five studies including a total of 835 patients, at an age range of 33.6-43.1 years and follow-up range of 60.0-78.0 months. All studies included PROs and all reported significant improvement (p<0.05) at the 5-year timepoint, with modified Harris Hip Score (mHHS) being the most frequent (n=6). No differences were noted between groups regarding any of the measured PROs. Average rates of achieving MCID and PASS for mHHS were similar between patients without capsular repair (MCID 71.1%, PASS 73.7%, n=1) and with capsular repair (MCID 66.0%-90.6%, PASS 55.3%-87.4%, n=4). Conversion to THA occurred in 12.8-18.5% and 0.0-29.0% for patients with an unrepaired and repaired capsule, respectively. Revision HA occurred in 15.4-25.5% and 3.1-15.4% in unrepaired and repaired capsular patients, respectively.

CONCLUSIONS

Patients undergoing hip arthroscopy for FAI had significant improvement in PRO scores at minimum 5-year follow-up, and scores did not differ between patients that underwent capsular repair and those that did not. Similar rates of markers of clinical benefit and THA conversion were achieved by both groups; however, lower rates of revision hip arthroscopy were demonstrated in the capsular repair cohort.

Arthroscopic Capsular Suture-Lifting Technique for Treating Femoroacetabular Impingement Patients With a High Risk of Postoperative Anterior Instability

With the increasing popularity of hip arthroscopy, postoperative iatrogenic instability due to bony and soft-tissue issues has been noted by more orthopaedic surgeons. Although there is a low risk of serious complications in patients with normal hip joint development even without suturing of the joint capsule, for patients with a preoperative high risk of anterior instability-including those with excessive anteversion of the acetabulum or femur, borderline dysplasia of the hip, and hip arthroscopic revision surgery with an anterior defect of the joint capsule-capsulotomy without repair will result in postoperative anterior instability of the hip joint and related symptoms. Capsular suturing techniques that provide anterior stabilization will be of great help for these high-risk patients and reduce the possibility of postoperative anterior instability. In this Technical Note, we introduce the arthroscopic capsular suture-lifting technique for treating femoroacetabular impingement (FAI) patients with a high risk of postoperative hip instability. In the past 2 years, the capsular suture-lifting technique has been used to treat FAI patients with borderline dysplasia of the hip and excessive femoral neck anteversion, and clinical results have shown that the suture-lifting technique provides a reliable and effective solution for FAI patients with a high risk of postoperative anterior hip instability.

Healing of joint capsule after hip arthroscopy using interportal capsulotomy and capsular closure influences clinical outcomes

Background

Hip arthroscopy for treatment of femoroacetabular impingement (FAI) has developed rapidly and has been shown to significantly decrease pain and improve hip function. However, the relationship between hip capsule characteristics and healing after arthroscopic surgery and changes in patient-reported outcomes scores (PROs) for postoperative pain, function, and symptoms is still uncertain.

Methods

We retrospectively evaluated consecutive patients who were diagnosed with FAI and underwent hip arthroscopy for treatment in our hospital between May 2018 and November 2020. All patients had preoperative MRI and postoperative MRI at least 6 months after arthroscopy. Hip capsular thickness was measured at the proximal, middle, and distal site of the capsule. PROs and PROs at final follow-up were obtained, including visual analog scale (VAS) for pain and modified Harris Hip Score (mHHS).

Results

A total of 194 patients were included in this study. The mean MRI follow-up time was 14.3 (range, 6–37) months, and the mean clinical follow-up time was 26.1 (range, 12–43) months. Postoperative capsular thickness or net change were not correlated with postoperative PROs and VAS (P > .05). Capsular defect was observed in 17 (8.8%) patients. Patients with capsular defect had a relatively higher BMI (P < .05). Patients with capsular defect had a significant lower mHHS and higher VAS compared with patients with continuous capsule (P < .05). Ninety-one percentage of patients with continuous capsule surpassed minimal clinically important difference (MCID) and 80.8% achieved PASS, but only 58.8% of patients with capsular defect surpassed MCID and 47.1% achieved patient acceptable symptom state (PASS).

Conclusions

Postoperative capsular thickness may not have influence on the clinical outcomes of hip arthroscopy for treatment of FAI. Some capsule of patients who underwent arthroscopic interportal capsulotomy and repair could not heal. Postoperative capsular continuity had a great impact on the clinical outcomes of hip arthroscopy for FAI. Patients with higher BMI may be more likely to have capsule failure to heal.

Arthroscopic Synovectomy of the Hip Joint: The Regional Surgical Technique

Synovial disease is a common reason for hip joint dysfunction. Although traditionally treated with open synovectomy, with the popularization and development of arthroscopic techniques, arthroscopic synovectomy has become the main surgical treatment for synovial diseases. Given the long soft tissue channel and learning curve, arthroscopic synovectomy of the hip joint has high surgical requirements for surgeons. However, there is currently no standardized surgical protocol for arthroscopic synovectomy of the hip joint to guide the surgeon to perform hip synovectomy in an orderly manner. During the past 3 years, we have employed a novel technique, wherein we divided the synovium of the hip into seven regions based on the anatomical structure and the operating range of the arthroscopic portals. With the assistance of flexion, extension, and traction of the hip joint, synovectomy was sequentially performed under arthroscopic guidance. This regional surgical technique can be popularized and likely has the potential to become a standardized arthroscopic synovectomy protocol of the hip joint.

Handle With Care: The Anterior Hip Capsule Plays a Key Role in Daily Hip Performance

Background:

Passive energy storage and return has long been recognized as one of the central mechanisms for minimizing the energy cost needed for terrestrial locomotion. Although the iliofemoral ligament (IFL) is the strongest ligament in the body, its potential role in energy-efficient walking remains unexplored.

Purpose:

To identify the contribution of the IFL to the amount of work performed by the hip muscles for normal, straight-level walking.

Study Design:

Controlled laboratory study.

Methods:

Straight-level walking of 50 healthy and injury-free adults was simulated using the AnyBody Modeling System. For each participant, the bone morphology and soft tissue properties were nonuniformly scaled. The superior and inferior parts of the IFL were represented by 2 springs each, and a linear force-strain relation was defined. A parameter study was conducted to account for the uncertainty surrounding the mechanical properties of the IFL. The work required from the gluteus, quadriceps, iliopsoas, and sartorius with and without inclusion of the IFL was calculated. Analysis of variance with subsequent post hoc paired t test was used to test the significance of IFL presence on the required mechanical work.

Results:

During walking, the strain in the IFL reached a median of 18.7% (95% CI, 8.0%-26.5%), with the largest values obtained at toe-off. With the IFL undamaged and fully operational, the effort required by the hip flexor muscles was reduced by a median of 54% (99% CI, 45%-62%) for the iliopsoas and by a median of 41% (99% CI, 27%-54%) for the sartorius muscles. The inclusion of the IFL did not significantly alter the work required by the gluteus and the quadriceps.

Conclusion:

The findings emphasized the key role the IFL plays in hip flexion by working synergistically with the hip musculature.

Clinical Relevance:

The importance of the contribution of the IFL to the hip flexors warrants careful handling and repair of these ligaments in cases of surgery and structural damage.