Achieving Successful Outcomes of Hip Arthroscopy in the Setting of Generalized Ligamentous Laxity With Labral Preservation and Appropriate Capsular Management: A Propensity Matched Controlled Study

Abstract

Background:

Association among generalized ligamentous laxity (GLL), hip microinstability, and patient-reported outcomes (PROs) after hip arthroscopy has yet to be completely established.

Purposes:

(1) To report minimum 2-year PROs in patients with GLL who underwent hip arthroscopy in the setting of symptomatic labral tears and femoroacetabular impingement syndrome and (2) to compare clinical results with a matched-pair control group without GLL.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Data from a prospectively collected database were retrospectively reviewed between August 2014 and December 2016. Patients were considered eligible if they received primary arthroscopic treatment for symptomatic labral tears and femoroacetabular impingement. Inclusion criteria included preoperative and minimum 2-year follow-up scores for the following PROs: modified Harris Hip Score (mHHS), Non-arthritic Hip Score (NAHS), and visual analog scale for pain (VAS). From the sample population, 2 groups were created: the GLL group (Beighton score ≥4) and the control group (Beighton score <4). Patients were matched in a 1:2 ratio via propensity score matching according to age, sex, body mass index, Tönnis grade, and preoperative lateral center-edge angle. Patient acceptable symptomatic state (PASS) and minimal clinically important difference (MCID) for mHHS, Hip Outcome Score–Sports Specific Scale (HOS-SSS), and International Hip Outcome Tool–12 (iHOT-12) were calculated.

Results:

A total of 57 patients with GLL were matched to 88 control patients. Age, sex, body mass index, and follow-up times were not different between groups (P > .05). Preoperative radiographic measurements demonstrated no difference between groups. Intraoperative findings and procedures between groups were similar except for capsular treatment, with the GLL group receiving a greater percentage of capsular plications (P = .04). At minimum 2-year follow-up, both groups showed significant improvement in PROs and VAS (P < .001). Furthermore, the postoperative PROs at minimum 2-year follow-up and the magnitude of improvement (delta value) were similar between groups for mHHS, NAHS, HOS-SSS, and VAS (P > .05). Moreover, groups reached comparable rates of MCID and PASS for mHHS, HOS-SSS, and iHOT-12.

Conclusion:

Patients with GLL after hip arthroscopy for symptomatic femoroacetabular impingement and labral tears may expect favorable outcomes with appropriate labral and capsular management at minimum 2-year follow-up. When compared with a pair-matched control group without GLL, results were comparable for mHHS, NAHS, HOS-SSS, and VAS and reached PASS and/or MCID for mHHS, HOS-SSS, and iHOT-12.

Keywords

hip arthroscopy ligamentous laxity femoroacetabular impingement patient-reported outcomes microinstability

Historically, the hip joint has been considered an inherently stable joint, with bony deficiency or hip dysplasia being a clear reason for instability.^48,49,84 However, features of microstability may be present even in the presence of appropriate acetabular coverage.³⁷ The concept of microinstability, defined as extraphysiologic hip motion as a consequence of bony deficiency and/or soft tissue damage or loss, has evolved from an abstract notion to a recognized source of symptoms in the hip.^72,74 A relationship between generalized ligamentous laxity (GLL) and its potential causation of hip micro-instability has been proposed.^30,36 GLL, defined as more-than-normal range of movement and usually measured with the Beighton score,⁵⁸ has been linked to several musculoskeletal injuries in knees and shoulders.^{9,34,39,41,82} Bin Abd Razak et al⁶ reported >3-times higher likelihood of such musculoskeletal injuries in patients with GLL. On the basis of a cohort of 1381 patients, Saadat et al⁷¹ recently reported the prevalence of GLL (Beighton score ≥4) in patients who underwent hip arthroscopy surgery, and they found that 18.9% were in fact patients with GLL.

In hip arthroscopy, the importance of capsule management has been increasingly acknowledged and may be critical in high-risk patients with GLL and/or features of some degree of acetabular dysplasia.^{2,19,32,49,62} Arthroscopic capsular plication has been described as an effective procedure to address microinstability in the hip.^13,23,80 Regarding GLL and outcomes after hip arthroscopy, there is a paucity in the current literature, with only a few studies reporting favorable results, most of which are limited by small series and relative short-term follow-up.^43,67,75

The purposes of the current study were (1) to report minimum 2-year patient-reported outcomes (PROs) in patients with GLL who underwent hip arthroscopy in the setting of symptomatic labral tears and femoroacetabular impingement syndrome (FAI) and (2) to compare clinical results with a matched-pair control group without GLL.

We hypothesized that (1) patients with GLL would experience favorable PROs at minimum 2-year follow-up and (2) clinical results in this group would be similar to those of a pair-matched control group without GLL.

Methods

Patient Selection

Data from a prospectively collected database at the American Hip Institute Hip Preservation Registry were retrospectively reviewed for patients who underwent hip arthroscopy between August 2014 and December 2016. All patients were considered eligible if they received primary arthroscopic treatment for labral tears in the setting of FAI and labral tears during this period. GLL was defined as Beighton score ≥4.⁷¹ Patients were included if they had preoperative scores and minimum 2-year follow-up scores for the following PROs: modified Harris Hip Score (mHHS),¹ Non-arthritic Hip Score (NAHS),¹⁵ and visual analog scale for pain (VAS).¹² Patients were excluded from analysis if they had a diagnosed ipsilateral hip condition (eg, avascular necrosis, Legg-Calvé-Perthes disease, or slipped capital femoral epiphysis), had concomitant surgery, underwent previous hip surgery, had a lateral center-edge angle (LCEA) <25°,⁵⁵ had workers’ compensation status, or had an unavailable Beighton score.

Participation in the American Hip Institute Hip Preservation Registry

While the present study represents a unique analysis, data on some patients in this study may have been reported in other studies.^14,64,71 All data collection received institutional review board approval (ID No. 5276).

Physical Examination

The senior surgeon (B.G.D.) performed a comprehensive physical examination on all patients during their preoperative clinic appointments.⁵² This evaluation included assessment of the patient’s gait, as well as the hip’s range of motion—internal rotation, external rotation, flexion, abduction, and adduction—as measured with the patient in the supine position. Hips were also evaluated with anterior, lateral, and posterior impingement tests, as well as for the presence of painful internal snapping with the hip flexed, abducted, and externally rotated. Additionally, the Beighton score was used preoperatively by the senior surgeon to assess ligamentous laxity.^5,51,71

Radiographic Imaging

A series of radiographic images were requested before surgery, including the standing and supine anteroposterior pelvis, modified 45° Dunn, and false-profile view.^16,25,57,77 Evaluations of these images were performed with General Electric Healthcare’s Picture Archiving and Communication System.

The anteroposterior supine view was used to assess the following: the LCEA of Wiberg⁸³ as modified by Ogata et al,⁶¹ the level of osteoarthritis as graded with the Tönnis system,²⁰ acetabular version as measured by the presence of crossover, and ischial spine and posterior wall signs.⁴⁵ Cam deformity was assessed on the 45° Dunn lateral view by measuring the alpha angle and the head-neck offset and defined as an alpha angle >55°.^50,66 Anterior center-edge angle of Lequesne and de Seze⁴⁴ was measured on the false-profile view. The institution’s radiographic measurements demonstrated good interobserver reliability in previously published studies.^22,69,70 Additionally, labral tears and other potential extra- and intra-articular defects were determined using magnetic resonance arthrography for all patients.

Surgical Indication and Technique

Patients were recommended arthroscopic surgery if radiographic imaging, history, and physical examination indicated evidence of FAI or labral tears. Specifically, patients experiencing moderate to severe pain were required to undergo at least 3 months of nonsurgical treatment, including physical therapy, nonsteroidal anti-inflammatory drugs, and activity modification. Patients were then recommended for surgery if the 3 months of nonoperative treatment failed.^8,28

All arthroscopies were performed by the senior author (B.G.D.). During surgery, patients were situated in the modified supine position.^17,40 A well-padded perineal post was used to aid in hip joint distraction. The anterolateral portal was created under fluoroscopic guidance to vent the joint and was followed by the midanterior and interportal capsulotomy under direct visualization.⁴⁶ A diagnostic arthroscopy was undertaken to make a full assessment of the hip joint. Ligamentum teres damage was graded using the Domb and Villar classifications.^7,27 Labral tears were measured and graded using the Seldes classification system.⁷³ The chondrolabral junction damage was graded using acetabular labrum articular disruption, while acetabular or femoral head chondral damage was recorded using the Outerbridge classifications.^54,63,76

Procedures were undertaken according to the intraoperative findings of hip pathology. Labral tears were debrided, repaired, or reconstructed on the basis of the size of the labrum, the extent of tearing, and the morphology/quality of the labrum.^21,47 Acetabuloplasty and femoral osteoplasty were performed under fluoroscopic guidance to treat pincer- and cam-type impingement, respectively.^50,68 Capsular plication was performed in all patients except those with excessive stiffness, adhesive capsulitis, or insufficient capsular tissue.^13,23 The technique for capsular plication was performed with the hip flexed to 45° and using absorbable sutures (2.0 coated Vicryl, polyglactin 910; Ethicon) and the 70° SlingShot Suture Manager (Pivot Medical, Inc).

One by one, 4 to 6 sutures were passed from the midanterior portal through the acetabular capsular side and retrieved from the distal anterolateral accessory portal through the capsular femoral side. All sutures were passed first from medial to lateral and tied in the same order. Preoperative characteristics, such as age, sex, body mass index (BMI), occupation, and desired activity level, also went into this multifactorial algorithm.

Rehabilitation Protocol

The postoperative protocol was tailored to accommodate recovery on the basis of the procedures performed, ranging from 2 to 8 weeks of recovery. All patients wore a brace for stability (DJO Global) and were limited to 20 lb (9 kg) of foot-flat weightbearing activity with crutches. Daily stationary bicycle usage was recommended for a total of 8 weeks postoperatively. Physical therapy began as early as 1 day after surgery.

Surgical Outcome Tools and Survivorship

Patients were prospectively assessed preoperatively, 3 months postoperatively, and annually thereafter using questionnaires to assess their outcomes. Patients completed the mHHS, NAHS, Hip Outcome Score–Sports Specific Scale (HOS-SSS),⁵³ and VAS outcome questionnaires pre- and postoperatively. Additionally, latest follow-up findings of the International Hip Outcome Tool–12 (iHOT-12), the Veterans RAND 12-Item Health Survey Physical Component Summary and Mental Component Summary, and the 12-Item Short Form Health Survey (SF-12) (Physical Component Summary and Mental Component Summary) were recorded.²⁹ Postoperative patient satisfaction on a scale from 0 to 10 and surgical complications were also recorded. The percentage of patients achieving the patient acceptable symptomatic state (PASS) and minimal clinically important difference (MCID) was found for the mHHS (PASS, ≥74 points; MCID, delta [Δ] ≥8 points)^20,21 and the HOS-SSS¹⁰ (PASS, ≥65 points; MCID, Δ≥6 points). Additionally, the PASS of iHOT-12 (≥63 points) was calculated.⁶⁰

Revision arthroscopic surgery was recorded for patients. Kaplan-Meier analysis was used to depict survivorship of the cohort, and comparisons were made using the log-rank test.

Statistical Analysis

Patients were matched on the logit of the propensity score via a nearest-neighbor (Euclidean distance) match algorithm. Matching was performed without replacement in a 1:2 ratio, and a strict caliper of 0.2 times the standard deviation of the logit propensity scores was used. Patients who were outside the caliper (“propensity range”) were removed from consideration.^3,4 The covariates were age at surgery, sex, BMI, Tönnis grade, and preoperative LCEA. Descriptive statistics were reported for patient characteristics, intraoperative findings, procedures performed, radiographic measurements, and PROs. A statistically significant difference was noted if P < .05. Continuous variables were reported in mean and standard deviations accompanied by 95% CIs. Parametricity and variance were assessed using the Shapiro-Wilk test and the F test, respectively. Normally distributed samples with equal variances were analyzed using a 2-tailed t test, whereas nonparametric data were compared using a nonparametric equivalent test. Chi-square (χ²) or Fisher exact test was used for all categorical variables. Based on the assumption that a mean difference of 8 points in follow-up mHHS between groups was clinically important, an a priori power analysis was used to determine that in a 1:2 matching ratio, 13 GLL cases and 26 control cases were necessary to achieve at least 80% power.⁶⁵ Statistical analysis was performed in Python (Version 3.7; Python Software Foundation) and R (Version 3.6.0; R Foundation).

Results

Patient Characteristics

During the study period, 275 patients satisfied the inclusion criteria, of whom 234 had adequate follow-up (85.1%). The patient selection flowchart is depicted in Figure 1. Of the 234 patients, 72 had a Beighton score ≥4. Patients with GLL were matched in a 1:2 ratio to those without GLL (control). Given the strict caliper, 57 patients with GLL were matched to 88 control patients. Characteristic data are presented in Table 1. The matched groups showed no significant differences in sex, age, BMI, Tönnis grade, and follow-up time (P > .05). Mean Beighton scores for the GLL and control groups were 5.68 and 0.96, respectively.

Figure 1.

Patient selection flowchart. GLL, generalized ligamentous laxity.

Table 1

Characteristics of the GLL and Control Groups After Propensity Score Matching^a

	GLL	Control	P Value
Hips included in study	57	88
Left	29	40	.64
Right	28	48
Sex
Female	50	77	.969
Male	7	11
Age at surgery, y	32.9 ± 12.6 (29.6-36.2)	36.9 ± 13.8 (34.1-39.8)	.064
BMI, kg/m²	25.9 ± 5.9 (24.4-27.5)	26.4 ± 5.2 (25.3-27.5)	.186
Follow-up time, mo	33.6 ± 8.1 (31.6-35.7)	32.3 ± 7.4 (30.8-33.8)	.348
Tönnis grade
0	49	79	.666
1	8	9

Values are presented as No. or mean ± SD (95% CI). BMI, body mass index; GLL, generalized ligamentous laxity.

Intraoperative Findings and Procedures

Intraoperative diagnostic data, presented in Table 2, demonstrated no difference between groups in labral tear type, acetabular or femoral head cartilage damage, or ligamentum teres injuries (P > .05). The procedures performed between groups were similar, with the exception of capsular treatment. A greater percentage of patients in the GLL group received capsular plications (P = .04) (Table 3).

Table 2

Intraoperative Findings of the GLL and Control Groups After Propensity Score Matching^a

	GLL	Control	P Value
Seldes type (labral tear)			.918
0	00 (0)	00 (0)
I	22 (38.6)	31 (35.2)
II	13 (22.8)	21 (23.9)
I and II	22 (38.6)	36 (40.9)
ALAD			.344
0	12 (21.1)	10 (11.4)
1	21 (36.8)	31 (35.2)
2	14 (24.6)	29 (33)
3	8 (14)	17 (19.3)
4	2 (3.5)	1 (1.1)
Outerbridge: acetabulum			.142
0	13 (22.8)	9 (10.2)
1	20 (35.1)	32 (36.4)
2	13 (22.8)	26 (29.5)
3	6 (10.5)	17 (19.3)
4	5 (8.8)	4 (4.5)
Outerbridge: femoral head			.814
0	54 (94.7)	81 (92)
1	00 (0)	00 (0)
2	1 (1.8)	1 (1.1)
3	1 (1.8)	2 (2.3)
4	1 (1.8)	4 (4.5)
LT percentile class (Domb)			.390
0: 0	42 (73.7)	57 (64.8)
1: 0 to <50	8 (14)	19 (21.6)
2: 50 to <100	6 (10.5)	7 (8)
3: 100	1 (1.8)	5 (5.7)
LT Villar class			.476
0: No tear	42 (73.7)	57 (64.8)
1: Complete tear	1 (1.8)	3 (3.4)
2: Partial tear	6 (10.5)	17 (19.3)
3: Degenerative tear	8 (14)	11 (12.5)

Values are presented as number of hips (%), unless otherwise stated. ALAD, acetabular labral articular disruption; GLL, generalized ligamentous laxity; LT, ligamentum teres.

Table 3

Intra-articular Procedures of the GLL and Control Groups After Propensity Score Matching

	GLL	Control	P Value
Labral treatment			.279
Debridement	1 (1.8)	7 (8)
Reconstruction	4 (7)	6 (6.8)
Repair	52 (91.2)	75 (85.2)
Capsular treatment			.040
Release	4 (7)	17 (19.3)
Repair	53 (93)	71 (80.7)
Acetabuloplasty	52 (91.2)	81 (92)	>.999
Femoroplasty	57 (100)	88 (100)	>.999
Microfracture
Acetabular	5 (8.8)	2 (2.3)	.112
Femoral head	00 (0)	4 (4.5)	.154
Ligamentum teres debridement	3 (5.3)	9 (10.2)	.366
Iliopsoas fractional lengthening	40 (70.2)	50 (56.8)	.149

Values are presented as number of hips (%), unless otherwise stated. Bold indicates statistical significance (P < .05). GLL, generalized ligamentous laxity.

Radiographic Findings

There were no significant differences between the groups in pre- or postoperative radiographic measurements (Table 4). Both groups showed significant reductions in alpha angle (P < .001).

Table 4

Radiographic Findings of the GLL and Control Groups After Propensity Score Matching^a

	GLL	Control	P Value
LCEA
Preoperative	31.00 ± 4.57 (29.81-32.19)	31.42 ± 4.47 (30.49-32.35)	.434
Postoperative	30.15 ± 4.08 (29.09-31.21)	30.07 ± 4.58 (29.11-31.03)	.960
P value	.110	.002
ACEA
Preoperative	31.67 ± 8.27 (29.53-33.82)	31.83 ± 6.10 (30.55-33.10)	.905
Postoperative	30.83 ± 6.57 (29.13-32.53)	32.42 ± 6.01 (31.17-33.68)	.094
P value	.749	.469
Acetabular inclination
Preoperative	4.16 ± 5.08 (2.84-5.48)	4.53 ± 3.75 (3.75-5.32)	.698
Postoperative	4.52 ± 4.25 (3.41-5.62)	4.71 ± 3.62 (3.95-5.46)	.841
P value	.762	.929
Alpha angle
Preoperative	53.70 ± 10.91 (50.87-56.53)	56.76 ± 11.41 (54.38-59.15)	.114
Postoperative	43.13 ± 5.14 (41.80-44.46)	43.09 ± 5.67 (41.91-44.28)	.763
P value	<.001	<.001

Values are presented as mean ± SD (95% CI). Bold indicates statistical significance (P < .05). ACEA, anterior center-edge angle; GLL, generalized ligamentous laxity; LCEA, lateral center-edge angle.

Surgical Outcomes

Pre- and postoperative recorded outcomes are presented in Table 5. Both groups reported significant increases for mHHS, NAHS, HOS-SSS, and VAS from baseline to minimum 2-year follow-up (P < .001). The minimum 2-year outcomescores showed no differences between the groups (P > .05). Similarly, the magnitude of improvement (Δ value) was comparable between groups (P > .05) (Figure 2).

Table 5

Baseline and Minimum 2-Year Patient-Reported Outcomes of the GLL and Control Groups After Propensity Score Matching^a

	GLL	Control	P Value
mHHS
Preoperative	61.02 ± 14.91 (57.15 to 64.89)	61.64 ± 16.94 (58.10 to 65.17)	.822
Latest	83.93 ± 17.89 (79.28 to 88.57)	87.47 ± 16.68 (83.98 to 90.95)	.210
P value	<.001	<.001
Δ	22.54 ± 20.23 (17.28 to 27.79)	25.47 ± 18.95 (21.51 to 29.42)	.382
NAHS
Preoperative	62.19 ± 18.07 (57.50 to 66.88)	59.73 ± 17.67 (56.04 to 63.42)	.418
Latest	84.24 ± 16.98 (79.83 to 88.65)	87.04 ± 18.14 (83.25 to 90.83)	.074
P value	<.001	<.001
Δ	21.88 ± 22.69 (15.98 to 27.77)	27.08 ± 19.24 (23.06 to 31.10)	.147
HOS-SSS
Preoperative	41.17 ± 24.09 (34.92 to 47.43)	37.68 ± 21.11 (33.27 to 42.09)	.377
Latest	75.51 ± 28.29 (68.16 to 82.85)	78.00 ± 24.68 (72.84 to 83.15)	.735
P value	<.001	<.001
Δ	35.31 ± 29.93 (27.54 to 43.08)	40.60 ± 27.53 (34.85 to 46.35)	.349
VAS
Preoperative	5.28 ± 1.95 (4.77 to 5.78)	5.22 ± 2.30 (4.74 to 5.70)	.804
Latest	2.46 ± 2.64 (1.77 to 3.14)	1.69 ± 2.22 (1.23 to 2.16)	.070
P value	<.001	<.001
Δ	−2.79 ± 3.00 (−3.57 to −2.01)	−3.52 ± 2.92 (−4.13 to −2.91)	.183
iHOT-12	75.88 ± 24.16 (69.61 to 82.15)	79.86 ± 24.95 (74.64 to 85.07)	.123
SF-12
Mental	53.98 ± 9.80 (51.44 to 56.53)	56.07 ± 7.80 (54.45 to 57.70)	.533
Physical	48.34 ± 9.73 (45.81 to 50.87)	49.81 ± 9.53 (47.82 to 51.80)	.232
VR-12
Mental	58.44 ± 10.46 (55.73 to 61.16)	60.94 ± 7.04 (59.46 to 62.41)	.127
Physical	49.55 ± 9.66 (47.05 to 52.06)	51.51 ± 8.45 (49.74 to 53.27)	.217
Patient satisfaction	7.71 ± 2.38 (7.10 to 8.33)	8.43 ± 2.41 (7.93 to 8.93)	.012

Values are presented as mean ± SD (95% CI). Bold indicates statistical significance (P < .05). Δ, delta value; GLL, generalized ligamentous laxity; HOS-SSS, Hip Outcome Score–Sports Specific Scale; iHOT-12, International Hip Outcome Tool–12; mHHS, modified Harris Hip Score; NAHS, Non-arthritic Hip Score; SF-12, 12-Item Short Form Health Survey; VAS, visual analog scale for pain; VR, Veterans RAND 12-Item Health Survey.

Figure 2.

Mean preoperative (Pre-op) and postoperative (Post-op) patient-reported outcomes (PROs) and 95% CIs for the generalized ligamentous laxity (GLL) and control groups. HOS-SSS, Hip Outcome Score–Sports Specific Scale; mHHS, modified Harris Hip Score; NAHS, Non-arthritic Hip Score.

There were no differences between the groups for the following PROs: iHOT-12, Veterans RAND 12-Item Health Survey (physical and mental), and SF-12 (physical and mental health) (P > .05). However, patient satisfaction scores between the groups were significantly different (P = .012) (Table 5).

When outcomes were translated to clinical terms, both groups reached similar levels for PASS and/or MCID for mHHS, HOS-SSS, and iHOT-12 (Table 6).

Table 6

MCID and PASS of the Generalized Ligamentous Laxity and Control Groups After Propensity Score Matching^a

	Laxity	Control	P Value
mHHS
PASS, 74	42 (82.4)	72 (86.7)	.658
MCID, Δ > 8	41 (80.4)	74 (89.2)	.247
HOS-SSS
PASS, 65	32 (78.0)	58 (77.3)	.930
MCID, Δ > 6	31 (86.1)	62 (89.9)	.748
iHOT-12
PASS, 63	40 (78.4)	68 (81.9)	.786

Values are presented as number of hips (%), unless otherwise stated. Δ, delta value; HOS-SSS, Hip Outcome Score–Sports Specific Scale; iHOT-12, International Hip Outcome Tool–12; MCID, minimal clinically important difference; mHHS, modified Harris Hip Score; PASS, patient acceptable symptomatic state.

Survivorship Analysis

Of the patients in the GLL group, 6 (10.5%) required a revision arthroscopy at a mean 16.35 months after findings of a retorn labrum in all 6, stiffness in 1, recalcitrant trochanteric bursitis in 1, and hip flexor tendinitis in 1. No patients with GLL converted to total hip replacement (total hip arthroplasty) at minimum 2-year follow-up. Of the patients in the control group, 4 (4.5%) required revision surgery at a mean 16.07 months, after the findings of a retorn labrum in all 4 and stiffness in 1. One (1.1%) patient in the control group converted to total hip arthroplasty at 32.12 months (Table 7). Figure 3 provides a Kaplan-Meier analysis demonstrating comparable conversions to revision arthroscopy between the groups.

Table 7

Secondary Surgery of the GLL and Control Groups After Propensity Score Matching^a

	Hips, No. (%) or Mean ± SD (95% CI)
	GLL	Control	P Value
Secondary arthroscopies	6 (10.5)	4 (4.5)	.192
Time to secondary arthroscopy, mo	16.35 ± 8.23 (9.76-22.94)	16.07 ± 8.60 (7.64-22.94)	.960
Total hip replacement	0	1 (1.1)	>.999
Time to total hip replacement, mo	N/A	32.12

Values are presented as number of hips (%) or mean ± SD (95% CI), unless otherwise stated. GLL, generalized ligamentous laxity; N/A, not applicable.

Figure 3.

Kaplan-Meier estimate of conversion to revision arthroscopy. Curves are accompanied by 95% CIs (Greenwood). GLL, generalized ligamentous laxity.

Discussion

The present study demonstrated that patients who underwent primary hip arthroscopy in the setting of FAI, labral tears, and GLL had favorable and significant improvements in PROs and VAS from baseline to minimum 2-year follow-up (P < .001 for mHHS, NAHS, HOS-SSS, VAS). In addition, favorable findings were demonstrated for patient satisfaction. Furthermore, when these improvements were translated to a clinical point of view, patients with GLL obtained favorable results in terms of MCID and/or PASS for mHHS, HOS-SSS, and iHOT-12. When the GLL group was compared with a pair-matched control group without GLL based on age, sex, BMI, Tönnis grade, and preoperative LCEA, no differences were observed in several PROs or VAS. Furthermore, the magnitude of improvement was comparable between groups in terms of mHHS, NAHS, HOS-SSS, and VAS. Moreover, no differences were observed between groups for the following clinical parameters: PASS and MCID for mHHS and HOS-SSS and PASS for iHOT-12.

Pontiff et al⁶⁷ reported results on arthroscopic management in women with GLL (Beighton score ≥4) and FAI. The authors compared 35 women with GLL and a group of 131 woman without GLL (Beighton score <4) and observed favorable and similar scores in HOS–Activities of Daily Living and iHOT-33. However, results were limited by the fact that the follow-up of the study was only 6 months, only 2 PROs for nonarthritic hips were assessed, and the groups were not matched.

With longer follow-up, Stone et al⁷⁵ recently published their results regarding patients with GLL (Beighton score ≥4) who underwent hip arthroscopy. The authors reported similar improvement in outcomes at average 2-year follow-up to a matched control group based on Δ value for mHHS (P = .913), HOS-SSS (P = .944), HOS–Activities of Daily Living (P = .618), and VAS (P = .512). Nonetheless, data regarding baseline PROs were not provided. In addition, the GLL group was composed of just 25 patients; only female patients were included for both groups; and details regarding follow-up differences between groups were not addressed. The baseline PROs were provided in the current study, and no differences were obtained between the matched groups. As mentioned before, comparable Δ values were obtained for the same PROs between groups. Regarding latest follow-up specific to hip preservation–designed PRO results, no differences were found. The authors of the previous study⁷⁵ stated that appropriate capsular management is essential to achieve good results in GLL populations, and we agree with this concept in addition to the combination of labral function/seal restoration.^2,24,59 In almost 94% of the patients, the capsule was plicated. The larger sample size, improved matching process, and longer follow-up made the results of the present study more generalizable than its predecessor.⁷⁵ Even in the presence of extreme capsular laxity (Ehlers-Danlos syndrome), meticulous capsular plication, FAI correction, and labral function restoration may lead to favorable short-term outcomes as reported by Larson et al.⁴³

Microinstability of the hip has evolved from an abstract concept to a recognized potential cause of pain and disability.^37,72 The association between GLL and microinstability has been proposed.^71,79 Trends show that capsular plication is becoming the standard in hip arthroscopy, and it is critical in high-risk populations, such as patients with GLL.^{18,23,26,62,81} Many cadaveric/biomechanics studies have investigated the relationship between capsular management and its role in the treatment of microinstability.^35,36,80 Jackson et al³⁵ found that the capsular shift procedure decreased internal rotation at low flexion angles, ease of distraction, and extension based on 8 fresh-frozen cadaveric hip dissections. Johannsen et al,³⁶ in a study with 8 hips, created a capsular laxity model and found a significant increase in femoral rotation and femoral head displacement. The authors concluded that the anterior hip capsule plays an important role in controlling hip rotation and femoral head displacement.

Recently, Saadat et al⁷¹ established the prevalence of GLL in patients undergoing hip arthroscopy. In a cohort of 1381 patients, there were 1120 patients with Beighton scores from 0 to 3 and 261 patients with Beighton scores ≥4 (GLL). In the GLL group, 92.7% of the patients were female. The likelihood of having GLL was almost 7 times higher for female versus male patients. This association between hip instability and sex has already been demonstrated by others.^2,42,49,78 The authors also reported lower age (mean ± SD: 38.9 ± 15.2 vs 31.0 ± 13.3 years; P < .0001) and BMI (26.7 ± 5.4 vs 24.9 ± 5.1 kg/cm²; P < .0001) for the GLL group. Additionally, they found that patients with GLL had greater hip range of motion and smaller intraoperative labral size and tear dimensions. Patients with GLL were also more likely to undergo labral repair, capsular plication, and iliopsoas fractional lengthening. However, the study was a cross-sectional design with no PRO analysis presented, a task addressed with the current investigation.

Strengths

Several notable strengths of the ongoing study must be mentioned. First, this is one of the few studies to report PROs specifically for patients with GLL at minimum 2-year follow-up. Second, these results were compared with a matched-pair control group without GLL to insulate the influence of GLL on outcomes. Third, based on an a priori power analysis, the sample sizes for both groups were adequately representative to detect meaningful differences, which drastically increases generalizability of the results. Fourth, the use of several PROs that were designed to detect outcomes in active patients with nonarthritic hips limited ceiling effects and warrants generalizability of the results.³⁸ Fifth, as statistical significance does not equate to clinical importance, the proportion of patients who achieved the MCID and/or PASS for mHHS, HOS-SSS, iHOT-12, and VAS was also calculated.³¹ Finally, while favorable outcomes have been reported with arthroscopic management of “borderline” hip dysplasia with FAI and labral tear, the potential confounding factor of any degree of dysplasia was eliminated by excluding any patients with an LCEA <25°.^19,33,49

Limitations

Limitations of the current study must be acknowledged. First, this was a nonrandomized study. As such, additional confounding variables may have influenced the results. Second, although data collection was done in a prospective manner, this is a retrospective study, which introduces bias. Third, the analysis was based on the patients of a single high-volume surgeon who specializes in hip preservation surgery, which may limit the generalizability of the results.⁵⁶ Fourth, capsular treatment was not included as a variable for the matching process and could have introduced confounding bias. Fifth, the present study included minimum 2-year follow-up, although longer follow-up is required to determine durability of the results. Surgical techniques involved in our treatment of patients with and without GLL have evolved and improved over time. As a result, while the GLL and control groups contain some patients who underwent capsulotomy without repair and labral debridement, today almost all such patients would be treated with capsular plication and an alternative for labral restoration (labral reconstruction/augmentation).¹¹ Sixth, because revision surgery was considered an endpoint outcome, PROs for these patients were not included in the PRO analysis. Seventh, the use of the Beighton score as a unique tool to address GLL is controversial.⁸¹ Eighth, Beighton scores were not available for the entire population; thus, these patients were excluded from analysis, resulting in a decrease of power of the study and potential bias. Ninth, GLL is not equal to microinstability⁷²; as such, the methodology of the present study was designed to address only the potential effect of GLL syndrome in patients who underwent hip arthroscopy in the setting of symptomatic labral tears and FAI. Last, dysplasia assessment based only on LCEA may be oversimplistic.⁵⁵

Conclusion

Patients with GLL after hip arthroscopy for symptomatic FAI and labral tears may expect favorable outcomes with appropriate labral and capsular management at minimum 2-year follow-up. When compared with a pair-matched control group without GLL, results were comparable for mHHS, NAHS, HOS-SSS, and VAS and reached the PASS and/or MCID for mHHS, HOS-SSS, and iHOT-12.

Footnotes

Submitted October 9, 2019; accepted February 4, 2020.

This study was performed in accordance with the ethical standards in the 1964 Declaration of Helsinki. This study was carried out in accordance with relevant regulations of the US Health Insurance Portability and Accountability Act. Details that might disclose the identity of the patients under study have been omitted. This study was approved by the institutional review board (ID 5276).

One or more of the authors has declared the following potential conflict of interest or source of funding: The American Hip Institute Research Foundation funded this research. B.G.D. has had ownership interests in Hinsdale Orthopaedics, the American Hip Institute, SCD#3, North Shore Surgical Suites, and Munster Specialty Surgery Center; has received research support from Arthrex, ATI, the Kauffman Foundation, Stryker, and Pacira Pharmaceuticals; has received consulting fees from Adventist Hinsdale Hospital, Arthrex, MAKO Surgical, Medacta, Pacira Pharmaceuticals, and Stryker; has received educational support from Arthrex, Breg, and Medwest; has received speaking fees from Arthrex and Pacira Pharmaceuticals; and receives royalties from Arthrex, DJO Global, MAKO Surgical, Stryker, and Orthomerica. B.G.D. is the medical director of hip preservation at St Alexius Medical Center and a board member for the American Hip Institute Research Foundation, AANA Learning Center Committee, the Journal of Hip Preservation Surgery, and the Journal of Arthroscopy. A.C.L. has received educational support from Medwest and Smith & Nephew; research support from Arthrex and Stryker; food and beverage from Smith & Nephew, Stryker, Zimmer Biomet, and Arthrex; travel and lodging from Stryker and Arthrex; and consulting fees from Arthrex and Graymont Medical. D.R.M., J.S., and P.J.R. have received hospitality payments from Arthrex, Stryker, and Smith & Nephew. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.

References

Aprato

Jayasekera

Villar

RN.

Does the modified Harris Hip Score reflect patient satisfaction after hip arthroscopy?

Am J Sports Med. 2012;40(11):2557-2560.

Ashberg

Charharbakhshi

Perets

Yuen

Walsh

Domb

BG.

Hip arthroscopic surgery with labral preservation and capsular plication in patients with borderline hip dysplasia: minimum 5-year patient-reported outcomes: response. Am J Sports Med. 2019;47(4):NP32-NP33.

Austin

PC.

Optimal caliper widths for propensity-score matching when estimating differences in means and differences in proportions in observational studies. Pharm Stat. 2011;10(2):150-161.

Austin

PC.

Some methods of propensity-score matching had superior performance to others: results of an empirical investigation and Monte Carlo simulations. Biom J. 2009;51(1):171-184.

Beighton

Horan

Orthopaedic aspects of the Ehlers-Danlos syndrome. J Bone Joint Surg Br. 1969;51(3):444-453.

Bin Abd Razak

Bin Ali

Howe

TS.

Generalized ligamentous laxity may be a predisposing factor for musculoskeletal injuries. J Sci Med Sport. 2014;17(5):474-478.

Botser

Martin

Stout

Domb

BG.

Tears of the ligamentum teres: prevalence in hip arthroscopy using 2 classification systems. Am J Sports Med. 2011;39(1)(suppl):117-125.

Briggs

Bolia

IK.

Hip arthroscopy: an evidence-based approach. Lancet. 2018;391(10136):2189-2190.

Chahal

Leiter

McKee

Whelan

DB.

Generalized ligamentous laxity as a predisposing factor for primary traumatic anterior shoulder dislocation. J Shoulder Elbow Surg. 2010;19(8):1238-1242.

10.

Chahal

Van Thiel

Mather

, et al. The patient acceptable symptomatic state for the modified Harris Hip Score and Hip Outcome Score among patients undergoing surgical treatment for femoroacetabular impingement. Am J Sports Med. 2015;43(8):1844-1849.

11.

Chandrasekaran

Darwish

, et al. Arthroscopic reconstruction of the irreparable acetabular labrum: a match-controlled study. Arthroscopy. 2019;35(2):480-488.

12.

Chandrasekaran

Gui

Walsh

Lodhia

Suarez-Ahedo

Domb

BG.

Correlation between changes in visual analog scale and patient-reported outcome scores and patient satisfaction after hip arthroscopic surgery. Orthop J Sports Med. 2017;5(9):2325967117724772.

13.

Chandrasekaran

Vemula

Martin

Suarez-Ahedo

Lodhia

Domb

BG.

Arthroscopic technique of capsular plication for the treatment of hip instability. Arthrosc Tech. 2015;4(2):e163-e167.

14.

Chen

Craig

Yuen

Ortiz-Declet

Maldonado

Domb

BG.

Five-year outcomes and return to sport of runners undergoing hip arthroscopy for labral tears with or without femoroacetabular impingement. Am J Sports Med. 2019;47(6):1459-1466.

15.

Christensen

Althausen

Mittleman

Lee

McCarthy

JC.

The nonarthritic hip score: reliable and validated. Clin Orthop Relat Res. 2003;406:75-83.

16.

Clohisy

Carlisle

Beaulé

, et al. A systematic approach to the plain radiographic evaluation of the young adult hip. J Bone Joint Surg Am. 2008;90(suppl 4):47-66.

17.

Domb

Hanypsiak

Botser

Labral penetration rate in a consecutive series of 300 hip arthroscopies. Am J Sports Med. 2012;40(4):864-869.

18.

Domb

Chaharbakhshi

Perets

Walsh

Yuen

Ashberg

LJ.

Patient-reported outcomes of capsular repair versus capsulotomy in patients undergoing hip arthroscopy: minimum 5-year follow-up—a matched comparison study. Arthroscopy. 2018;34(3):853-863.

19.

Domb

Chaharbakhshi

Perets

Yuen

Walsh

Ashberg

Hip arthroscopic surgery with labral preservation and capsular plication in patients with borderline hip dysplasia: minimum 5-year patient-reported outcomes. Am J Sports Med. 2018;46(2):305-313.

20.

Domb

Chaharbakhshi

Rybalko

Litrenta

Perets

Outcomes of hip arthroscopic surgery in patients with Tönnis grade 1 osteoarthritis at a minimum 5-year follow-up: a matched-pair comparison with a Tönnis grade 0 control group. Am J Sports Med. 2017;45(10):2294-2302.

21.

Domb

Hartigan

Perets

Decision making for labral treatment in the hip: repair versus débridement versus reconstruction. J Am Acad Orthop Surg. 2017;25(3):e53-e62.

22.

Domb

Martin

Gui

Chandrasekaran

Suarez-Ahedo

Lodhia

Predictors of clinical outcomes after hip arthroscopy: a prospective analysis of 1038 patients with 2-year follow-up. Am J Sports Med. 2018;46(6):1324-1330.

23.

Domb

Philippon

Giordano

BD.

Arthroscopic capsulotomy, capsular repair, and capsular plication of the hip: relation to atraumatic instability. Arthroscopy. 2013;29(1):162-173.

24.

Domb

Yuen

Ortiz-Declet

Litrenta

Perets

Chen

AW.

Arthroscopic labral base repair in the hip: 5-year minimum clinical outcomes. Am J Sports Med. 2017;45(12):2882-2890.

25.

Dunn

DM.

Anteversion of the neck of the femur: a method of measurement. J Bone Joint Surg Br. 1952;34(2):181-186.

26.

Ekhtiari

de Sa

Haldane

, et al. Hip arthroscopic capsulotomy techniques and capsular management strategies: a systematic review. Knee Surg Sports Traumatol Arthrosc. 2017;25(1):9-23.

27.

Gray

Villar

RN.

The ligamentum teres of the hip: an arthroscopic classification of its pathology. Arthroscopy. 1997;13(5):575-578.

28.

Griffin

Dickenson

Wall

PDH

, et al. Hip arthroscopy versus best conservative care for the treatment of femoroacetabular impingement syndrome (UK FASHIoN): a multicentre randomised controlled trial. Lancet. 2018;391(10136):2225-2235.

29.

Griffin

Parsons

Mohtadi

NGH

Safran

; Multicenter Arthroscopy of the Hip Outcomes Research Network. A short version of the International Hip Outcome Tool (iHOT-12) for use in routine clinical practice. Arthroscopy. 2012;28(5):611-616.

30.

Han

Alexander

Thomas

, et al. Does capsular laxity lead to microinstability of the native hip? Am J Sports Med. 2018;46(6):1315-1323.

31.

Harris

Brand

Cote

Faucett

Dhawan

Research pearls: the significance of statistics and perils of pooling, part 1: clinical versus statistical significance. Arthroscopy. 2017;33(6):1102-1112.

32.

Hatakeyama

Utsunomiya

Nishikino

, et al. Predictors of poor clinical outcome after arthroscopic labral preservation, capsular plication, and cam osteoplasty in the setting of borderline hip dysplasia. Am J Sports Med. 2018;46(1):135-143.

33.

Hevesi

Hartigan

Levy

Domb

Krych

AJ.

Are results of arthroscopic labral repair durable in dysplasia at midterm follow-up? A 2-center matched cohort analysis. Am J Sports Med. 2018;46(7):1674-1684.

34.

Hiemstra

Kerslake

Kupfer

Lafave

MR.

Generalized joint hypermobility does not influence clinical outcomes following isolated MPFL reconstruction for patellofemoral instability. Knee Surg Sports Traumatol Arthrosc. 2019;27(11):3660-3667.

35.

Jackson

Peterson

Akeda

, et al. Biomechanical effects of capsular shift in the treatment of hip microinstability: creation and testing of a novel hip instability model. Am J Sports Med. 2016;44(3):689-695.

36.

Johannsen

Behn

Shibata

Ejnisman

Thio

Safran

MR.

The role of anterior capsular laxity in hip microinstability: a novel biomechanical model. Am J Sports Med. 2019;47(5):1151-1158.

37.

Kalisvaart

Safran

MR.

Microinstability of the hip—it does exist: etiology, diagnosis and treatment. J Hip Preserv Surg. 2015;2(2):123-135.

38.

Kemp

Collins

Roos

Crossley

KM.

Psychometric properties of patient-reported outcome measures for hip arthroscopic surgery. Am J Sports Med. 2013;41(9):2065-2073.

39.

Kim

S-J

Choi

Lee

S-K

Lee

Jung

Minimum two-year follow-up of anterior cruciate ligament reconstruction in patients with generalized joint laxity. J Bone Joint Surg Am. 2018;100(4):278-287.

40.

Lall

Saadat

Battaglia

Maldonado

Perets

Domb

BG.

Perineal pressure during hip arthroscopy is reduced by use of Trendelenburg: a prospective study with randomized order of positioning. Clin Orthop Relat Res. 2019;477(8):1851-1857.

41.

Larson

Bedi

Dietrich

, et al. Generalized hypermobility, knee hyperextension, and outcomes after anterior cruciate ligament reconstruction: prospective, case-control study with mean 6 years follow-up. Arthroscopy. 2017;33(10):1852-1858.

42.

Larson

Ross

Stone

, et al. Arthroscopic management of dysplastic hip deformities: predictors of success and failures with comparison to an arthroscopic FAI cohort. Am J Sports Med. 2016;44(2):447-453.

43.

Larson

Stone

Grossi

Giveans

Cornelsen

GD.

Ehlers-Danlos syndrome: arthroscopic management for extreme soft-tissue hip instability. Arthroscopy. 2015;31(12):2287-2294.

44.

Lequesne M

de Seze.

False profile of the pelvis: a new radiographic incidence for the study of the hip. Its use in dysplasias and different coxopathies [in French]. Rev Rhum Mal Osteoartic. 1961;28:643-652.

45.

Litrenta

Chen

Ortiz-Declet

Perets

Domb

BG.

Radiographic and clinical outcomes of adolescents with acetabular retroversion treated arthroscopically. J Pediatr Orthop. 2019;39(10):510-515.

46.

Maldonado

Chen

Walker-Santiago

, et al. Forget the greater trochanter! Hip joint access with the 12 o’clock portal in hip arthroscopy. Arthrosc Tech. 2019;8(6):e575-e584.

47.

Maldonado

Lall

Walker-Santiago

, et al. Hip labral reconstruction: consensus study on indications, graft type and technique among high-volume surgeons. J Hip Preserv Surg. 2019;6(1):41-49.

48.

Maldonado

LaReau

Perets

, et al. Outcomes of hip arthroscopy with concomitant periacetabular osteotomy, minimum 5-year follow-up. Arthroscopy. 2019;35(3):826-834.

49.

Maldonado

Perets

, et al. Arthroscopic capsular plication in patients with labral tears and borderline dysplasia of the hip: analysis of risk factors for failure. Am J Sports Med. 2018;46(14):3446-3453.

50.

Mansor

Perets

Domb

BG.

In search of the spherical femoroplasty: cam overresection leads to inferior functional scores before and after revision hip arthroscopic surgery. Am J Sports Med. 2018;46(9):2061-2071.

51.

Martin

HD.

Clinical examination of the hip. Oper Tech Orthop. 2005;15(3):177-181.

52.

Martin

Kelly

Leunig

, et al. The pattern and technique in the clinical evaluation of the adult hip: the common physical examination tests of hip specialists. Arthroscopy. 2010;26(2):161-172.

53.

Martin

Philippon

MJ.

Evidence of reliability and responsiveness for the Hip Outcome Score. Arthroscopy. 2008;24(6):676-682.

54.

McCarthy

Noble

Aluisio

Schuck

Wright

Lee

Anatomy, pathologic features, and treatment of acetabular labral tears. Clin Orthop Relat Res. 2003;406:38-47.

55.

McClincy

Wylie

Yen

Y-M

Novais

EN.

Mild or borderline hip dysplasia: are we characterizing hips with a lateral center-edge angle between 18° and 25° appropriately?

Am J Sports Med. 2019;47(1):112-122.

56.

Mehta

Chamberlin

Marx

, et al. Defining the learning curve for hip arthroscopy: a threshold analysis of the volume-outcomes relationship. Am J Sports Med. 2018;46(6):1284-1293.

57.

Meyer

Beck

Ellis

Ganz

Leunig

Comparison of six radiographic projections to assess femoral head/neck asphericity. Clin Orthop Relat Res. 2006;445:181-185.

58.

Naal

Hatzung

Müller

Impellizzeri

Leunig

Validation of a self-reported Beighton score to assess hypermobility in patients with femoroacetabular impingement. Int Orthop. 2014;38(11):2245-2250.

59.

Nho

Beck

Nwachukwu

, et al. Survivorship and outcome of hip arthroscopy for femoroacetabular impingement syndrome performed with modern surgical techniques. Am J Sports Med. 2019;47(7):1662-1669.

60.

Nwachukwu

Chang

Beck

, et al. How should we define clinically significant outcome improvement on the iHOT-12? HSS J. 2019;15(2):103-108.

61.

Ogata

Moriya

Tsuchiya

Akita

Kamegaya

Someya

Acetabular cover in congenital dislocation of the hip. J Bone Joint Surg Br. 1990;72(2):190-196.

62.

Ortiz-Declet

Chen

, et al. Should the capsule be repaired or plicated after hip arthroscopy for labral tears associated with femoroacetabular impingement or instability? A systematic review. Arthroscopy. 2018;34(1):303-318.

63.

Outerbridge

RE.

The etiology of chondromalacia patellae. J Bone Joint Surg Br. 1961;43:752-757.

64.

Perets

Chaharbakhshi

Shapira

Ashberg

Domb

BG.

Hip arthroscopy for femoroacetabular impingement and labral tears in patients younger than 50 years: minimum five-year outcomes, survivorship, and risk factors for reoperations. J Am Acad Orthop Surg. 2019;27(4):e173-e183.

65.

Perets

Rybalko

, et al. 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. Am J Sports Med. 2018;46(14):3437-3445.

66.

Philippon

Briggs

Stull

LaPrade

RF.

Prevalence of increased alpha angles as a measure of cam-type femoroacetabular impingement in youth ice hockey players. Am J Sports Med. 2013;41(6):1357-1362.

67.

Pontiff

Ithurburn

Ellis

Cenkus

Stasi

SD.

Pre- and post-operative self-reported function and quality of life in women with and without generalized joint laxity undergoing hip arthroscopy for femoroacetabular impingement. Int J Sports Phys Ther. 2016;11(3): 378-387.

68.

Redmond

El Bitar

Gupta

Stake

Vemula

Domb

BG.

Arthroscopic acetabuloplasty and labral refixation without labral detachment. Am J Sports Med. 2015;43(1):105-112.

69.

Redmond

Gupta

Dunne

Humayun

Yuen

Domb

BG.

What factors predict conversion to THA after arthroscopy?

Clin Orthop Relat Res. 2017;475(10):2538-2545.

70.

Redmond

Gupta

Hammarstedt

Stake

Dunne

Domb

BG.

Labral injury: radiographic predictors at the time of hip arthroscopy. Arthroscopy. 2015;31(1):51-56.

71.

Saadat

Lall

Battaglia

Mohr

Maldonado

Domb

BG.

Prevalence of generalized ligamentous laxity in patients undergoing hip arthroscopy: a prospective study of patients’ clinicalpresentation, physical examination, intraoperative findings, and surgicalprocedures. Am J Sports Med. 2019;47(4):885-893.

72.

Safran

MR.

Microinstability of the hip-gaining acceptance. J Am Acad Orthop Surg. 2019;27(1):12-22.

73.

Seldes

Tan

Hunt

Katz

Winiarsky

Fitzgerald

RH.

Anatomy, histologic features, and vascularity of the adult acetabular labrum. Clin Orthop Relat Res. 2001;382:232-240.

74.

Shu

Safran

MR.

Hip instability: anatomic and clinical considerations of traumatic and atraumatic instability. Clin Sports Med. 2011;30(2):349-367.

75.

Stone

Mehta

Beck

, et al. Comparable patient-reported outcomes in females with or without joint hypermobility after hip arthroscopy and capsular plication for femoroacetabular impingement syndrome. J Hip Preserv Surg. 2019;6(1):33-40.

76.

Suarez-Ahedo

Gui

Rabe

Chandrasekaran

Lodhia

Domb

BG.

Acetabular chondral lesions in hip arthroscopy: relationships between grade, topography, and demographics. Am J Sports Med. 2017;45(11):2501-2506.

77.

Tönnis

Heinecke

Acetabular and femoral anteversion: relationship with osteoarthritis of the hip. J Bone Joint Surg Am. 1999;81(12):1747-1770.

78.

Ukwuani

Waterman

Nwachukwu

, et al. Return to dance and predictors of outcome after hip arthroscopy for femoroacetabular impingement syndrome. Arthroscopy. 2019;35(4):1101-1108.

79.

van Arkel

Amis

Cobb

Jeffers

JRT.

The capsular ligaments provide more hip rotational restraint than the acetabular labrum and the ligamentum teres. Bone Joint J. 2015;97(4):484-491.

80.

Waterman

Chen

Neal

, et al. Intra-articular volume reduction with arthroscopic plication for capsular laxity of the hip: a cadaveric comparison of two surgical techniques. Arthroscopy. 2019;35(2):471-477.

81.

Westermann

Bessette

Lynch

Rosneck

Does closure of the capsule impact outcomes in hip arthroscopy? A systematic review of comparative studies. Iowa Orthop J. 2018;38:93-99.

82.

Whitehead

Mohammed

Fulcher

ML.

Does the Beighton score correlate with specific measures of shoulder joint laxity?

Orthop J Sports Med. 2018;6(5):2325967118770633.

83.

Wiberg

Shelf operation in congenital dysplasia of the acetabulum and in subluxation and dislocation of the hip. J Bone Joint Surg Am. 1953;35(1):65-80.

84.

Wyles

Heidenreich

Jeng

Larson

Trousdale

Sierra

RJ.

The John Charnley Award: redefining the natural history of osteoarthritis in patients with hip dysplasia and impingement. Clin Orthop Relat Res. 2017;475(2):336-350.