The Incidence and Outcomes Following Treatment of Capsulolabral Adhesions in Hip Arthroscopy: A Systematic Review

Abstract

Background

To perform a systematic review to evaluate the incidence of capsulolabral adhesions following hip arthroscopy (HA) for femoroacetabular impingement (FAI); including risk factors and post-treatment outcomes.

Methods

Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we queried PubMed, EMBASE, and Cochrane Central Register of Controlled Trials for English-language studies with minimum 6-month follow-up after primary or revision HA for FAI, which reported the incidence of capsulolabral adhesions. Potential adhesion risk factors, such as anchor type used and protocol for capsule closure, were assessed. Pre-operative and post-operative modified Harris Hip Score (mHHS) values were compared in studies that reported them.

Results

Thirty-seven articles were included (24 primary HA; 13 revision HA). There were 6747 patients who underwent primary HA (6874 hips; 3005 female, 44%). The incidence of capsulolabral adhesions, confirmed surgically during revision HA, was low. Patients undergoing surgical treatment reported postoperative improvement per modified Harris Hip Scores. Data for 746 patients undergoing second revision HA (761 hips; 449 female, 60%), showed an incidence of adhesions greater than that of primary HA patients.

Conclusion

While the incidence of symptomatic capsulolabral adhesions after primary hip arthroscopy is low; revision hip arthroscopy is strongly associated with adhesion development. Lysis of adhesions in primary hip arthroscopy patients reliably improved patient-reported outcomes.

Level of Evidence: IV

Introduction

Hip arthroscopy (HA) has exponentially gained popularity in the last two decades as a means of treating femoroacetabular impingement (FAI) with an 18-fold increase from 1999 to 2009; and a nearly 4-fold increase from 2004 to 2009 alone.^1,2 As with any new procedure, greater utilization has highlighted pearls, pitfalls, outcome ratios, and success rates of the intervention.

The etiology of persistent pain following hip arthroscopy can be elusive. Residual impingement, failure of labral repair, new tears of the labrum, chondral defects, previously unaddressed or iatrogenic instability, femoral and/or acetabular version, and development adhesions are among possible differential diagnoses.³ In all patients, some degree of scar tissue formation between the hip joint capsule and labrum occurs during postoperative healing. However, the development of tough, fibrous bands of scar tissue—capsulolabral adhesions—can pathologically adhere the hip joint capsule to the acetabular labrum. These adhesions impact range of motion and disrupt the fluid seal of the hip joint, increasing friction forces on the chondral cartilage. Despite evidence that adhesions are a frequent generator of postoperative hip pain, they remain poorly understood and sparingly researched.^4,5

This paucity of knowledge includes precipitating factors, diagnostic strategies, preventive approaches, and treatment options.^3,4,6 Greater emphasis should be placed on exploring these factors, given the prevalent role of adhesions in cases of failed primary hip arthroscopy. This can significantly improve primary HA outcomes and decrease the need for revision HA. Therefore, this study aimed to perform a systematic review of capsulolabral adhesion incidence, precipitating intra-operative factors, and patient outcomes after current treatment approaches.

Methods

Literature Search

Search strategies were developed with the assistance of an orthopedic health sciences librarian with expertise in systematic reviews. Searches were developed by the authors and the librarian beginning in July 2019 using an iterative process of gathering and evaluating terms. The final literature search was performed and completed in December 2020. Comprehensive strategies, including both index and keyword terms, were devised for the following databases: PubMed (including MEDLINE), Embase (Elsevier platform), and Cochrane Central (Wiley platform). To maximize sensitivity, pre-established database filters other than the English language filter were not used. The full PubMed search strategy below was adapted for use with the other electronic databases. Complete search strategies are available upon request. Supplementary approaches for searching included reviewing reference lists of the included studies. Please see Appendix I for MESH terms.

Our aggregate PubMed search combined these component searches as follows: (#1 OR #2) AND #3 NOT (#4 OR #5). When limited to English language results, 722 papers were found. After performing a similarly focused search via Embase and Cochrane, duplicates were removed using an approach to ensure accuracy and prevent accidental loss of records. This process was facilitated by citation management software and supplemented by manual review of records. Our initial search yielded 1481 results that were evaluated according to our inclusion and exclusion criteria (Table I). Two authors, with oversight from the senior authors, reviewed 198 full papers and screened-in 37 final studies for qualitative analysis (Figure I).

Table I.

Review Criteria

Inclusion Criteria	Exclusion Criteria
Articles describing primary or revision hip preservation surgery for FAI	Review articles
Assessment of incidence of capsu- lolabral adhesions and arthroscopic lysis of adhesions	Case reports
Evaluation of patient characteristics related to capsulolabral adhesions	Technique articles
Evaluation of strategies to prevent adhesion development	Non-english language articles
Evaluation of objective or subjective outcomes of patients after lysis of adhesions
Minmum mean follow-up of 6 months for reported outcomes

Figure I.

Flow diagram of systematic search performed based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist.

Statistical Analyses

Excel v.1808 (Microsoft Inc, Redmond, WA) was utilized to perform basic demographic calculations and all Student t-tests. Student t-tests evaluated demographic data among all patients including mean age, mean percent of female patients, and mean length of follow-up; these values were calculated for multiple population subgroups to ensure appropriate between-groups demographic homogeneity.

Outcome Variables

For patients undergoing primary hip arthroscopy, the principal outcome variable was the number of patients (count or percent) with capsulolabral adhesions subsequently confirmed on revision HA indicated for persistent hip symptoms. For studies with no incidence of revision HA for adhesions, it was also acceptable for data to be presented in unambiguous text format. If the studies mentioned specific postoperative interventions aiming to prevent adhesions after primary HA, such as use of continuous passive motion machines or prescribed circumduction exercises, this data was recorded as well.

In studies of patients undergoing revision hip arthroscopy, the principal outcome variable was number of patients (count or percent) with intra-operative confirmation of capsulolabral adhesions. Similar to the analysis of the primary HA studies, if revision HA studies mentioned specific postoperative interventions designed to prevent adhesions, this data was recorded with other study information. To approximate success of the revision HA procedures, pre- and postoperative modified Harris Hip Scores (mHHS) were recorded if included in the study; however, mHHS was not a requirement for study inclusion during the screening process.

Two subgroup analyses of primary and revision HA patients were performed to evaluate potential intra-operative precipitants of symptomatic postoperative adhesions: suture anchor composition and hip joint capsule closure protocol. Hip arthroscopy patients noted to undergo labral repair with knotted or knotless sutures were identified, and incidence rates of postoperative capsulolabral adhesions compared. Similarly, patients undergoing procedures where capsular closure or non-closure was documented were identified, to compare development of capsulolabral adhesions. For both subgroup analyses, adequate data was only present among primary HA studies.

Study Quality

The mean Modified Coleman Methodology Score (MCMS) was assessed for each included study by two authors, individually, before consensus scores were determined. The mean MCMS score for the included studies was 70.11 ± 8.58 (Table II), considered “good” per MCMS standards. The mean MCMS of the primary HA cohort was significantly greater than the revision HA cohort (75.3 ± 5.2 vs. 70.5 ± 3.5, p=0.002), likely due to the weight MCMS assigns to study size, and size differences between the primary and revision study cohorts (Primary 8.6 ± 2.3 vs. Revision 4.8 ± 2.8, p=0.0067). Please see Appendix II for full MCMS for each study.

Table II.

Summary of Article Methodology Assessment According to the Modified Coleman Methodology Score

Primary HA		Revision HA
Author & Year	Total Score (100)	Author & Year	Total Score (100)
Buchler et al. 2013	67	Philippon 2008	56
Arashi et al. 2019	73	Karthikeyan et al. 2012	64
Bolia et al. 2019	85	Aprato et al. 2014	66
Philippon 2012	66	Larson 2013	73
Domb et al. 2013	73	Ross et al. 2015	50
Matsuda et al. 2013	70	Gupta et al. 2016	71
Willimon et al. 2014	74	Gwathmey et al. 2017	71
Byrd et al. 2014	70	Philippon 2018	76
Fukui et al. 2015	82	Locks 2018	71
Gupta et al. 2016	79	Nwachuku et al. 2018	60
Sawyer et al. 2015	74	Fagottia et al. 2019	73
Byrd et al. 2016	74	Arriaza et al. 2020	51
Nawabi et al. 2016	68	Cancienne et al. 2020	73
Degen 2017	60
Weber 2017	64
Nho et al. 2019	69
Webb 2019	53
Brick et al. 2020	85
Filan et al. 2020	71
Hwang et al. 2020	82
Makovicka et al. 2020	70
Menge et al. 2020	77
Philippon 2020	77
Philippon 2012	76
Mean	70.11
SD	8.58

Study Heterogeneity

Due to the paucity of literature on this topic, a systematic review of heterogenous studies was indicated. To better explore this heterogeneity and potential impacts on study findings, Table III and Figure II can be referenced. Table III details design characteristics and properties of included studies. Figure II is an index random effects model for the review, focused on one of the subgroup analyses—use of knotted versus knotless sutures. The resulting I2 heterogeneity, 86%, reinforces the need for high-level homogenous studies on the topic.

Table III.

Characteristics of Included Articles

Authors	Study Type	Level of Evidence	Total Patients	Total Hips	Male	Female	Mean Age (Range or ±SD)	Mean Follow-up (Months, Range or ±SD)
Primary HA
Buchler et al.	Retrospective Cohort	III	66	66	17	49	33.8	11.3 (1.5-55)
Arashi et al.	Retrospective Cohort	III	33	36	22	11	16.7	24 (15-32)
Bolia et al.	Retrospective Comparative	III	126	126	72	54	38	82.2
Philippon	Case Series	IV	153	153	72	81	57 (50-77)	35.7 (12-52)
Domb et al.	Case Series	IV	22	22	4	18	20 (14-39)	27.5
Matsuda et al.	Retrospective Cohort	III	54	54	32	22	37.08 ± 18.24	30 (24-27)
Willimon et al.	Retrospective Cohort	III	1264	1264	752	512	32 ± 11	12
Byrd et al.	Case Series	IV	37	38	26	11	26	24
Fukui et al.	Case Series	IV	100	102	50	50	35 (18-69)	40 (24-97)
Gupta et al.	Case Series	IV	546	546	228	318	38 (13.2-76.4)	28.98 (24-66.1)
Sawyer et al.	Retrospective Cohort	III	326	326	162	164	34.6 (18-64)	37.4 (24-61.2)
Byrd et al.	Case Series	IV	104	116	47	57	16 (12-17)	38 (24-120)
Nawabi et al.	Retrospective Cohort	III	177	207	82	95	29.7 ± 10	31.3 ± 7.6
Degen	Retrospective Comparative	III	34	38	18	16	16 (13-17)	36.1
Weber	Case Series	IV	59	59	23	16	31.7 ± 11.4	12.5 ± 6.8
Nho et al.	Retrospective Case-Control	III	935	935	347	588	33 ± 12.3	27.8
Webb	Retrospective Cohort	III	950	1010	591	419	36 (14-72)	18
Brick et al.	Retrospective Cohort	III	228	228	120	108	34.5	60.95
Filan et al.	Retrospective Comparative	III	966	966	829	137	28.05	28.8
Hwang et al.	Retrospective Cohort	III	162	162	89	73	35.1 (15-69)	87.4 (60-244)
Makovicka et al.	Retrospective Cohort	III	85	85	53	32	29.7	29.1
Menge et al.	Case Series	IV	60	70	21	49	16 ± 1.2	144 (120-168)
Philippon	Case Series	IV	200	200	118	82	35.3	43.8
Philippon	Case series	IV	60	65	17	43	15	24 (12-38)
Revision HA
Philippon	Case Series	IV	9	9	5	4	37.2 (21-49)	20 (10-36)
Karthikeyan et al.	Case Series	IV	20	20	16	4	37 (17-54)	17
Aprato et al.	Case Series	IV	63	63	27	36	37 ± 10.7	36
Larson	Retrospective Cohort	III	79	85	35	44	29.5 (16-59)	26 (12-72)
Ross et al.	Retrospective Cohort	III	50	50	33	27	29 (16-52)	-
Gupta et al.	Case Series	IV	70	70	31	39	36.3 (16.8-70.2)	27.99
Gwathmey et al.	Case Series	IV	186	190	69	117	32.7 (14-64)	46.9 (24-60)
Philippon	Case Series	III	99	99	36	63	29 ± 10	40
Locks	Retrospective Comparative	III	26	28	8	18	33 ± 14	43.2 ± 12
Nwachuku et al.	Case Series	IV	49	49	22	27	29.7 ± 8.6	12
Fagottia et al.	Retrospective Cohort	III	36	36	9	27	30.4	25 (18-38)
Arriaza et al.	Case Series	IV	10	13	6	4	36.3 ± 15.5	26.3 ± 13.85
Cancienne et al.	Retrospective Comparative	III	49	49	10	39	30 ± 10.5	25 ± 3.5

Figure II.

Random effect model comparing the pooled prevalence of adhesions in labral repairs with knotted versus knotless suture anchors. There was no difference in adhesion incidence between anchor types (p=0.18).

Results

Eligibility and Patient Characteristics

Our literature screen identified 37 qualifying studies, 24 of which addressed primary hip arthroscopy (Table III). There were 6747 patients (3005 female, 44%) in the primary HA cohort. One hundred fifteen patients in this group underwent bilateral HA (1.9%) for a total of 6874 operative hips. The mean age was 30.2 ± 9.8 years and mean follow-up was 39.0 ± 29.3 months. Body mass index (BMI) was reported in 12 of 24 articles for an attenuated mean of 24.48 ± 2.3 kg/m². The operative side was not consistently reported.

The revision HA cohort consisted of 737 patients, with 14 patients (1.9%) undergoing bilateral revision HA, for a total of 751 operative hips. There were 303 males (40%) and 445 females (60%). The mean age of patients was 32.9 ± 3.4 years and mean follow-up was 30.3 ± 9.7 months. The mean BMI was only reported in 3 of 13 articles and thus was negligible statistically. The operative side was not reported consistently.

Indications and Procedures

Of the 24 studies in the primary HA group, patients in 20 studies were indicated for surgery for FAI, while patients in four studies (493 hips; 7% of primary HA cohort) had a dual surgical indication of FAI and borderline hip dysplasia (lateral center edge angle 18-25°^7,8 or 20-25°.)^9,10 Among all 24 primary HA studies (6874 hips), 77% (5263 hips) underwent labral repair, 59% (4034 hips) underwent femoral osteochondroplasty, 52% (3568 hips) underwent acetabular rim trimming, 8% (572 hips) underwent acetabular or femoral microfracture, and 3% (223 hips) underwent labral reconstruction. It is important to note that patients likely underwent two or more of the above interventions during surgery. Five studies^11-15 (325 hips; 5% of group total) evaluated postoperative outcomes; all patients were adolescents.

The 13 revision HA study patients were indicated for surgery for various diagnoses: all including FAI. Among the 750 operative hips, 21% (160 hips) underwent labral repair,15% (115 hips) underwent labral reconstruction, 61% (465 hips) underwent femoral osteochondroplasty, 38% (287 hips) underwent acetabular rim trimming, and 9% (65 hips) underwent acetabular or femoral microfracture.

In the subgroup analysis of capsule closure vs. non-closure, 18 of 24 primary HA studies reported capsule closure (14 studies;^7-9,11,13-22 3055 hips) or non-closure (4 studies,^10,12,16,23 842 hips), while two of thirteen revision HA studies mentioned capsule management: Philippon et al.²⁴ (99 hips) performed capsule repair, and Locks et al.²⁵ performed capsule reconstruction with iliotibial band autograft.

For the subgroup analysis of suture anchor type, 11 of 24 primary HA studies reported use of knotted suture anchors (7 studies;^{8,9,12,22,26-28} 1933 hips) versus knotless suture anchors (4 studies; 389 hips), and one revision HA study (13 hips) reported use of knotless suture anchors Among the eleven primary HA studies with this data, two studies (222 hips) were specifically involving patients treated with labral reconstruction.^22,29

Incidence of Capsulolabral Adhesions

The incidence of capsulolabral adhesions after primary HA was globally low but not negligible, with incidence rate among studies ranging from 0% to 25.9%. Almost all the primary HA patients suspected of having capsulolabral adhesions were treated with revision HA for lysis of adhesions in addition to correction of any residual pathology, if needed. In the four primary HA studies where patients had both FAI and borderline dysplasia, the incidence of capsulolabral adhesions confirmed during revision HA was lower than collective incidence rates among studies of FAI-only patients, with rates ranging from 0% to just 6.86%.

Demographic Variables of Patients with Capsulolabral Adhesions

Patient demographics including age, sex, and BMI were not regularly reported in the included studies, limiting availability of this data for specifically adhesion patients. Thus, index studies providing comprehensive data were examined as a proxy. The primary HA study by Matsuda et al. identified 57 patients with adhesions (29 females, 50.9%), who had a mean age of 32 ± 11 years and mean BMI of 24 ± 4 kg/m².²⁹ Another primary HA study identified 3 patients with adhesions (2 females, 66.7%) with a mean age of 16 years³⁰ and a third primary HA study reported adhesions in 2 females (100%) with no specified age.¹¹

One revision HA study reported 15 cases of adhesions (9 female; 60%) with a mean age of 23.2 ± 8 years²⁴ while another revision HA study noted 36 cases of adhesions (9 female; 75%)with a mean age of 30 years and mean BMI of 22.8 kg/m².³¹ A third revision HA study identified 13 patients with adhesions, with a mean age of 27.9 ± 8.5 years. No other studies in the primary or revision HA cohorts reported demographics of patients treated for capsulolabral adhesions.

The limited number of studies reporting demographics of adhesion patients precluded any generalizable conclusions, but the three studies each from the primary and revision cohorts did allow for limited assessment of trends. For example, five studies provided mean patient ages—32, 16, 23.2, 30, and 27.9—indicating that symptomatic adhesions may be less likely among adolescent patients. One study each from the primary and revision HA groups reported a mean healthy BMI in adhesion patients; too small of a data pool for use beyond forming future research hypotheses.

Capsulolabral Adhesion Subgroup Analyses

Adhesions occurred in 86 of the 1933 hips reported to use knotted suture anchors (4.45%), and in 38 of the 402 hips reported to use knotless suture anchors (9.45%), demonstrating no substantial impact of suture anchor type on development of adhesions. Number of anchors used at index procedure was not regularly reported. When evaluating capsule management, adhesions occurred in 152 of 3055 hips that underwent capsule closure (4.37%) and, in almost identical proportion, in 11 of 842 hips with no capsule closure (4.33%). The subgroup analyses indicated that these specific intra-operative variables did not have a significant impact on development of postoperative adhesions.

Patient Outcome After Treatment of Adhesions

Overall, 811 hips in the present review had revision HA which surgically confirmed capsulolabral adhesions and treated them with lysis. A limited analysis of postoperative patient-reported outcomes—the modified Harris Hip Score (mHHS)— following this intervention for adhesions was performed. Eight of 14 studies (560 hips, 69%) reported improvement in modified Harris Hip scores (mHHS) after undergoing revision HA with lysis of adhesions, indicating the lysis of adhesions is a reasonable early treatment consideration for this condition.

Prevention of Adhesions

Thirteen studies reported trial protocols for postoperative capsulolabral adhesion prophylaxis. All 13 studies emphasized the potential benefit of early postoperative passive range of motion activities, specifically use of continuous passive motion (CPM) machines or regular performance of hip circumduction exercises. Willimon et al. and Menge et al. provide practice-level support for these recommendations.^14,38 Both authors noted decreased development of postoperative capsulolabral adhesions in their hip preservation patients after implementation of a rehabilitation protocol which included early use of CPM and performance of circumduction exercises.

Discussion

When analyzing study data from 6747 patients undergoing primary hip arthroscopy (HA), a low but not inconsequential number had capsulolabral adhesions confirmed on revision hip arthroscopy (range: 0% to 25%). With a mean follow-up of 39.6 months, many of these cases of adhesions requiring surgical intervention occurred within the first three postoperative years. However, intraoperative findings from 737 revision hip arthroscopy patients revealed that capsulolabral adhesion incidence rates may in fact be much higher, with the adhesions either not rising to the level of clinical significance for the patient or being misdiagnosed as one of the many other potential post-arthroscopy problems. Among all 13 revision HA studies, the main surgical indication was FAI syndrome and associated osteochondral procedures. Despite this, nearly one in three patients (224/737, 30.0%) were found to have capsulolabral adhesions requiring lysis during their procedures. In the subgroup analysis, neither suture anchor type nor capsule closure protocol appeared to influence rate of adhesions.

It cannot be concluded in isolation that capsulolabral adhesions alone caused the symptomatology of the revision HA patients, particularly when so many were indicated for surgery for objectively confirmed pathology, such as FAI detected on imaging. However, treatment of the adhesions with lysis did not appear to have a detrimental impact in any patients, with 8 of the 14 studies recording mHHS showing improved scores after revision HA with lysis of adhesions.

Recovery from hip arthroscopy requires maintaining ”homeostasis” of soft tissue and osseous healing within an optimal range.^32,33 Failure of a repaired labrum to heal translates to failure of the procedure, and failure of appropriate healing at osteochondral sites in the pelvis could put the patient at serious risk given the continual weightbearing demands on the pelvis. Appropriate osseous healing after hip arthroscopy involving offset correction is the development of bony callus over resection sites, followed by coverage with mature bone.^32,34-36 However, excessive osseous healing has been shown to cause heterotopic ossification in post-hip arthroscopy patients; where extra-articular bone formation along portal tracks can cause pain and debility, and require further surgical intervention.^32-36 Similarly, inappropriate healing of incised/repaired soft tissue after hip arthroscopy, forming fibrotic tissue, can, cause symptomatic and functional setbacks, requiring revision HA.^3,37

Capsulolabral adhesions can cause painful pathologic mechanisms of movement in the hip joint.^3,4,37 Adhesions to the labrum can prevent it from maintaining an adequate seal with the femoral head throughout various ranges of motion.^4,38 Loss of this seal can result in loss of fluid tension within the joint, thus increasing frictional stresses between joint components.^4,5 This friction can cause pain and mechanical symptoms, which may necessitate revision HA for lysis of adhesions; even if symptoms are not severe enough to require revision HA, there remains a risk of increased rate of chondral degeneration.^3,5

Because hip arthroscopy is a relatively young field, work is ongoing to determine optimal treatment for postoperative complications, and to elucidate possible prevention strategies.^33,37 A relevant example is the earlier treatment of HO with revision surgery, followed by the development of strategies such as HO prophylaxis with naproxen or celecoxib (NSAIDs), with a goal of superseding the need for revision HA.^34,39 Current literature lacks a consensus opinion on the use of NSAIDs for adhesion prophylaxis. Currently, revision HA for lysis of adhesions is the only effective treatment for symptomatic capsulolabral adhesions.^3,37 However, the procedure and its efficacy are not a flawless solution. As shown in the present review, adhesions can be a significant source of continued pain and functional impairment in HA patients; one in four revision HA patients required this additional surgery due to adhesions. While this review shows improvement in hip-relevant patient-reported outcomes after lysis of adhesions, it is important to consider the number of patients with adhesions who are not able to or willing to undergo revision HA, and continue to suffer from pain and reduced functional status.^3,37

Just as revision HA was not an optimal solution for HO, it is similarly not an optimal solution for capsulolabral adhesions.⁴ Intra-operative and postoperative prevention strategies are being investigated. One modifiable intra-operative consideration is the use of knotted versus knotless suture anchors.⁴⁰ Preliminary research shows no significant difference in incidence of adhesions with use of knotted versus knotless suture anchors;⁴⁰ similar to the findings of the present study. However, knotless sutures had a higher rate of adhesions that did not reach significance, and sporadic reporting of suture anchor type consequently made the analysis low power. A dedicated, higher power investigation may clarify these findings. Postoperative prevention strategies range from chemoprophylaxis with anti-fibrotic medications such as losartan, to mechanical prophylaxis using continuous passive motion or scheduled circumduction exercises.^4,38,41 There is currently no high-quality literature demonstrating consistent success with any of these methods.

Limitations

The present review has several limitations. First, the results of the review are limited by the quality of evidence of each individual study included. All articles were Levell III or IV evidence and mostly single surgeon series. FAI syndrome encompasses several potential sites of pain generation, and operative treatment often requires many concomitant procedures to address intra-and extra-articular sites of impingement. Operative management also differs between primary and revision HA. There were indeed differences in procedures performed between the primary and revision HA cohorts, which likely explains the differences in the incidence rates of capsulolabral adhesions. However, studies did not address which specific pathologies are potentially risk factors for adhesion development. In addition, procedural information is limited by data available in each study. Not every study reported the number of patients who received a specific procedure during hip arthroscopy and as such, we were unable to stratify by bony versus non-bony procedures performed. This could be a focus for future investigations.

Conclusion

While the incidence of symptomatic capsulolabral adhesions after primary hip arthroscopy is low; revision hip arthroscopy is strongly associated with adhesion development. Lysis of adhesions in primary hip arthroscopy patients reliably improved patient-reported outcomes.