Patient-Reported Outcomes Are Similar in the First 2 Years After Staged Versus Combined Hip Arthroscopy and Periacetabular Osteotomy for Hip Dysplasia.

PURPOSE: To compare early patient-reported outcomes after staged versus combined hip arthroscopy and periacetabular osteotomy for hip dysplasia. METHODS: A prospective database was retrospectively reviewed to identify patients that underwent combined or staged hip arthroscopy and periacetabular osteotomy (PAO) from 2012 to 2020. Patients were excluded if they were >40 years of age, had prior ipsilateral hip surgery, or did not have at least 12-24 months of postoperative patient-reported outcome (PRO) data. PROs included the Hip Outcomes Score (HOS) Activities of Daily Living (ADL) and Sports Subscale (SS), Non-Arthritic Hip Score (NAHS), and the Modified Harris Hip Score (mHHS). Paired t-tests were used to compare preoperative to postoperative scores for both groups. Outcomes were compared using linear regression adjusted for baseline characteristics, including age, obesity, cartilage damage, acetabular index, and procedure timing (early vs late practice). RESULTS: Sixty-two hips were included in this analysis (39 combined, 23 staged). The average length of follow-up was similar between the combined and staged groups (20.8 vs 19.6 months; P = .192). Both groups reported significant improvements in PROs at final follow up compared to preoperative scores (P < .05 for all). There were no significant differences in HOS-ADL, HOS-SS, NAHS, or mHHS scores between groups preoperatively or at 3, 6, or 12 months postoperatively (P > .05 for all). There was no significant difference in PROs between the combined and staged groups at the final postoperative time point: HOS-ADL (84.5 vs 84.3; P = .77), HOS-SS (76.0 vs 79.2; P = .68), NAHS (82.2 vs 84.5; P = .79), and mHHS (71.0 vs 71.0, P = .75), respectively. CONCLUSIONS: Staged hip arthroscopy and PAO for hip dysplasia leads to similar PROs at 12-24 months compared to combined procedures. This suggests that with careful and informed patient selection, staging these procedures is an acceptable option for these patients and does not change early outcomes. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Segmental and Circumferential Acetabular Labral Reconstruction Have Comparable Outcomes in the Treatment of Irreparable or Unsalvageable Labral Pathology: A Systematic Review.

PURPOSE: To perform a systematic review comparing outcomes of segmental versus circumferential arthroscopic labral reconstruction as a treatment for symptomatic irreparable or unsalvageable acetabular labral pathology. METHODS: A systematic review was conducted according to PRISMA guidelines using defined inclusion and exclusion criteria. The study groups were divided into segmental and circumferential labral reconstructions. Studies with <2 years follow up, overlapping patient populations, or indications for labral reconstruction other than irreparable or unsalvageable pathology were excluded. RESULTS: The literature search resulted in nine included publications. Five studies presented data on segmental labral reconstruction (166 hips in 164 patients), and seven studies presented data on circumferential labral reconstruction (261 hips in 253 patients). All circumferential reconstruction studies used allograft only, while segmental studies used a combination of autograft and allograft. The range of conversion to total hip arthroplasty was 9.1% to 26.8% in the segmental studies and 3.1% to 9.9% in the circumferential studies. The modified Harris Hip Score (mHHS) was the only patient-reported outcome measure reported in three or more studies in both groups. The mean change from preoperative to postoperative mHHS ranged from 17.8 to 29 in the segmental group and from 20.4 to 31.7 in the circumferential group. Weighted estimates were not calculated due to significant heterogeneity for both the segmental and circumferential groups (I2 = 63.9% and 72.9%, respectively). CONCLUSIONS: Segmental and circumferential reconstructions are both reasonable options for arthroscopic treatment of irreparable or unsalvageable labral pathology. Articles in both groups demonstrated improvement in patient-reported outcomes (mHHS). Because of study heterogeneity, low level of evidence, and high risk of bias, the scores were unable to be directly compared. Although there are theoretical biomechanical and technical advantages of one technique over another, this systematic review did not demonstrate clinical superiority of either technique. LEVEL OF EVIDENCE: Level IV, systematic review of level III and IV studies.

Biomechanical Response to Distraction of Hip Capsular Reconstruction With Human Acellular Dermal Patch Graft.

PURPOSE: To quantify the biomechanical properties of the hip capsule with human dermal allograft reconstruction to determine whether a dermal patch restored capsular resistance to distraction. METHODS: Nine cadaveric hip specimens were dissected until capsule and bony structures remained and were then mounted in a testing fixture in neutral flexion and abduction. Four states of the hip capsule were sequentially tested under axial distraction of 5 mm measured with video analysis and with resultant force measurement: (1) intact hip capsule, (2) interportal capsulotomy, (3) capsulectomy to the zona orbicularis, and (4) capsular reconstruction with human dermal allograft using acetabular anchors and capsule-to-patch sutures. RESULTS: Capsulectomy was different from intact (P = .036), capsulotomy differed from capsulectomy (P = .012), and the repair was statistically significantly different from capsulectomy (P = .042); intact and reconstructed cases were not statistically significantly different. The force required for 5 mm of distraction decreased after interportal capsulotomy by an average of 9% compared with the intact state and further decreased after capsulectomy by 30% compared with the intact state. After capsular reconstruction using dermal allograft, force requirements increased by an average of 36% from the capsulectomy state, only 5% below the intact state. CONCLUSIONS: Human dermal allograft tissue graft provides restoration of distractive strength for use during hip capsule reconstruction with acetabular anchor fixation and distal soft-tissue fixation after capsulectomy in a cadaveric model. CLINICAL RELEVANCE: Capsular repair or reconstruction with a dermal patch offers time-zero restoration of function; intact and reconstructed cases showed no difference, and reconstruction restored a capsulectomy to a biomechanical equivalent of the intact case when distraction was applied.

The Utility of Hip Arthroscopy in the Setting of Acetabular Dysplasia: A Systematic Review.

PURPOSE: To compare patient-reported outcomes, progression of osteoarthritis, and conversion to total hip replacement in a dysplastic population when hip arthroscopy was used as an isolated treatment or as an adjunct to pelvic reorientation osteotomy. METHODS: An exhaustive search of the existing literature was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Three databases (PubMed, CINAHL [Cumulative Index to Nursing and Allied Health Literature], Embase) were searched for studies from January 1930 through January 2018 published in the English language concerning the use of hip arthroscopy with diagnostic and therapeutic intentions in individuals with acetabular dysplasia. We excluded studies that presented ambiguous data sets or in which clear identification of the strategy for arthroscopy was absent. RESULTS: The selection criteria were defined, and 33 studies (1,368 hip arthroscopies) were included in the final analysis. Studies that met the inclusion criteria were classified within 5 different categories: (1) hip arthroscopy for screening, chondral mapping, and planning (9 studies, 729 hip arthroscopies); (2) isolated arthroscopic treatment (13 studies, 434 hip arthroscopies); (3) outcomes of hip arthroscopy after previous reorientation pelvic osteotomy for acetabular dysplasia (4 studies, 52 hip arthroscopies); (4) arthroscopy followed by unplanned hip-preservation surgery (3 studies, 48 hip arthroscopies); and (5) combined arthroscopy and periacetabular osteotomy (4 studies, 106 hip arthroscopies). A risk-of-bias analysis showed a moderate to high risk of bias (level 3 or 4) within and across the included studies. CONCLUSIONS: Although hip arthroscopy can be used to accurately grade the severity of chondral injuries in the native hip and provide zone-specific geographic mapping that may aid in subsequent surgical planning, there is insufficient evidence to conclude that arthroscopic characterization alone has any bearing on the ultimate clinical outcomes after osseous structural correction. Isolated arthroscopic treatment is not recommended in the setting of moderate to severe dysplasia, given the inferior clinical outcomes and risk of iatrogenic instability reported for this group. However, there is limited evidence to suggest that the isolated use of hip arthroscopy may be considered in cases of borderline acetabular dysplasia when careful attention is paid to labral and capsular preservation. Limited evidence supports the conclusion that after prior reorientation pelvic osteotomy for acetabular dysplasia, hip arthroscopy leads to improved clinical and functional outcomes and should be considered in this setting. Furthermore, there is insufficient evidence to conclude that failed hip arthroscopy compromises or challenges the ultimate clinical outcomes in patients undergoing subsequent reorientation pelvic osteotomy. Last, there is insufficient evidence to conclude that the adjunctive use of hip arthroscopy with reorientation pelvic osteotomy produces superior clinical outcomes compared with pelvic osteotomy alone. In summary, arthroscopic techniques may provide a useful complement to the correction of acetabular dysplasia and should be thoughtfully considered on a case-by-case basis when designing a comprehensive treatment strategy in dysplastic populations. LEVEL OF EVIDENCE: Level IV, systematic review of Level III and IV studies.

The Effect of Intra-articular Cocktail Versus Femoral Nerve Block for Patients Undergoing Hip Arthroscopy.

PURPOSE: To compare clinical efficacy and complication rate as measured by postoperative falls and development of peripheral neuritis between intra-articular blockade and femoral nerve block in patients undergoing arthroscopic hip surgery. METHODS: An institutional review board approved retrospective review was conducted on a consecutive series of patients who underwent elective arthroscopic hip surgery by a single surgeon, between November 2013 and April 2015. Subjects were stratified into 2 groups: patients who received a preoperative femoral nerve block for perioperative pain control, and patients who received an intra-articular "cocktail" injection postoperatively. Demographic data, perioperative pain scores, narcotic consumption, incidence of falls, and iatrogenic peripheral neuritis were collected for analysis. Postoperative data were then collected at routine clinical visits. RESULTS: A total of 193 patients were included in this study (65 males, 125 females). Of them, 105 patients received preoperative femoral nerve blocks and 88 patients received an intraoperative intra-articular "cocktail." There were no significant differences in patient demographics, history of chronic pain (P = .35), worker's compensation (P = .24), preoperative pain scores (P = .69), or intraoperative doses of narcotics (P = .40). Patients who received preoperative femoral nerve blocks reported decreased pain during their time in PACU (P = .0001) and on hospital discharge (P = .28); however, there were no statistically significant differences in patient-reported pain scores at postoperative weeks 1 (P = .34), 3 (P = .64), and 6 (P = .70). Administration of an intra-articular block was associated with a significant reduction in the rate of postoperative falls (P = .009) and iatrogenic peripheral neuritis (P = .0001). CONCLUSIONS: Preoperative femoral nerve blocks are associated with decreased immediate postoperative pain, whereas intraoperative intra-articular anesthetic injections provide effective postoperative pain control in patients undergoing arthroscopic hip surgery and result in a significant reduction in the rate of postoperative falls and iatrogenic peripheral neuritis. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

The Utility of Postoperative Radiographs 2 Years After Primary Total Knee Arthroplasty.

BACKGROUND: Radiographs are routinely used to evaluate patients postoperatively after total knee arthroplasty, but no evidence-based guidelines exist regarding their use. The purpose of this study is to quantify the use of radiographs within 2 years of primary total knee arthroplasty by one surgeon and to determine if routine studies in asymptomatic patients altered patient management. METHODS: Patients undergoing consecutive primary total knee arthroplasties between 2008 and 2010 were identified. Patients undergoing revision or additional simultaneous procedures or those with less than 6 months of radiographic follow-up were excluded. Operative and clinic notes, radiographs, and radiology reports were reviewed. RESULTS: A total of 263 patients were identified; each patient had an average of 13.5 ± 3.8 individual radiographs obtained in 6.5 ± 1.7 series. Twelve radiographic series were noted to have abnormal findings by either the attending surgeon or by radiology report. Three of these patients underwent reoperation directly related to the findings; 2 for deep infections and 1 for extensor mechanism disruption. All 3 patients had reported abnormal symptoms when their films were obtained. The remaining 9 abnormal radiographic findings included focal lucencies or osteolysis, asymmetric spacer wear, a healing stress fracture, an inferior patellar avulsion fracture, and heterotopic ossification. No patient had symptoms attributable to these findings when the radiographs were obtained, and in no case was the management altered based on these finding. CONCLUSION: This study suggests that the observed frequency of routine postoperative radiographs in asymptomatic patients may not be necessary in the first 2 years after primary total knee arthroplasty.

Comparison of Two Injection Techniques for Intra-articular Hip Injections.

OBJECTIVES: Intra-articular hip joint injections have traditionally relied on the use of image guidance to confirm intra-articular needle placement. Musculoskeletal ultrasound (US) has emerged as a popular tool to aid the clinician in performing intra-articular hip injections. Modern automated injection delivery systems are commercially available and may offer the potential to optimize clinical efficiency while limiting procedural morbidity. The purpose of this study was to compare patient-reported outcomes and clinical efficiency between two US-guided intra-articular hip injection techniques. The hypothesis was that the use of an automated delivery system for US-guided intra-articular hip joint injections would show superiority in clinical efficiency over traditional syringe injections. METHODS: This study was a level 1 randomized prospective postmarket clinical evaluation. Forty patients were randomly assigned to undergo a single intra-articular corticosteroid injection of the hip using either an automated delivery system (Navigator Delivery System; Carticept Medical, Inc, Alpharetta, GA) or a traditional syringe injection. Enrolled patients were prospectively followed at 1, 6, and 12 weeks after injection. A battery of patient-reported outcomes were collected at baseline and again at 1, 6, and 12 weeks after injection. Preparation times were documented for all injections. RESULTS: Forty patients met inclusion criteria and were enrolled. Twenty patients were randomly assigned to receive US guided intra-articular hip injections using the automated system (group A), and 20 patients were treated with standard syringe injections (group B). Body mass index, smoking history, symptom duration, baseline patient-reported outcomes, and demographic data were similar between groups. Improvements from baseline scores were noted at all time points for all patient-reported outcomes regardless of the injection technique used. However, no significant differences were noted at any time point for any of the patient-reported outcomes based on which injection delivery system was used. Statistically significant differences were noted at 6 and 12 weeks for the subjective global assessment score, which favored the use of the automated delivery system over the standard injection technique (6 weeks, P = .029; 12 weeks, P = .028). Between the two injection procedures, there was no difference in pain experienced by the patient (mean Visual Analog Scale pain score ± SEM: group A, 34.9 ± 6.49; group B, 34.5 ± 5.99; P = .960). Body mass index did not influence pain associated with an intra-articular hip injection (P = .870); however, younger patient age was found to be an independent predictor of increased pain associated with injection (P = .011). Although there were no differences among male or female patients in hip injection pain based on the delivery method, statistically significant differences were encountered between male and female patients, irrespective of treatment assignment (male/female: group A, 25.1/41.4; group B, 26.7/46.1; P= .049). Among patients with a smoking history, large differences were noted for injection pain when data for both groups were pooled, regardless of the delivery method (no history, 30.0 ± 4.86; smoking history, 40.8 ± 9.94). Clinical efficiency (as measured by injection preparation time) was found to be inferior for the automated system compared to traditional syringe injection (P < .0001). CONCLUSIONS: Use of an automated delivery system for US-guided intra-articular hip injections did not show superior efficiency or patient comfort over traditional syringe injections. Intra-articular corticosteroid injections led to clinically and statistically significant improvements in pain and function for patients with intra-articular hip pain, irrespective of the delivery method. Smoking history and female sex were independent predictors of increased pain associated with intra-articular hip joint injections.

Does Femoroacetabular Impingement Cause Hip Instability? A Systematic Review.

PURPOSE: To determine whether femoroacetabular impingement (FAI) is associated with hip instability. METHODS: A systematic search examining FAI and hip instability was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Clinical and basic science studies were included. Instability had to be documented with either a clinical or imaging examination. Studies were excluded if they did not define diagnostic criteria for FAI, involved prosthetic hips, were not in English, were review articles, or reported Level V evidence (case reports, expert opinion). Rates of FAI morphologic features in patients with documented hip instability were determined. Mechanisms and rates of FAI-induced hip subluxation were examined in basic science studies. RESULTS: The search yielded 1,630 relevant studies. Seven studies (4 clinical and 3 basic science) met inclusion criteria. Four studies investigated an association between FAI and hip instability in 92 patients with an average age of 31 years. Seventy-six patients experienced frank dislocations and 16 experienced posterior subluxation events. The prevalence of FAI was documented in 89 patients with hip instability. The rates of cam and pincer morphologic characteristics were 74% and 64%, respectively. The average lateral center edge angle and prevalence of acetabular retroversion were 30° and 70%, respectively (n = 76 patients). All 3 basic science studies had real-time visualization of FAI-induced hip subluxations. CONCLUSIONS: High rates of FAI morphologic characteristics are present in patients with hip instability. FAI morphologic characteristics may predispose the hip to instability through anatomic conflict caused by pincer or cam lesions (or both) levering the femoral head posteriorly. LEVEL OF EVIDENCE: Level IV, systematic review of Level III, Level IV, and non-clinical studies.

Acetabular Labral Debridement/Segmental Resection Versus Reconstruction in the Comprehensive Treatment of Symptomatic Femoroacetabular Impingement: A Systematic Review.

PURPOSE: To perform a systematic review comparing outcomes of labral debridement/segmental resection with labral reconstruction as part of a comprehensive treatment strategy for femoroacetabular impingement. METHODS: A systematic review was conducted according to established PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines using defined inclusion and exclusion criteria. The study groups were divided into labral debridement/segmental resection (group 1) and labral reconstruction (group 2). Multiple search engines were queried (PubMed, Medline) for this analysis. RESULTS: After an exhaustive search of the available literature, 20 publications were included. Twelve studies explored outcomes after labral debridement/resection in a total of 400 hips, whereas 7 studies reported on outcomes after labral reconstruction in a total of 275 hips. One additional matched-pair control study compared labral resection (22 hips) with reconstruction (11 hips). The surgical intervention was a revision in 0% to 100% for group 1 versus 5% to 55% for group 2. A direct anterior approach was not performed in group 2, and cam-type impingement appeared to make up a larger percentage of group 1. The Tönnis grade ranged from 0 to 1 for group 1 versus 0.3 to 1.1 for group 2. Joint replacements were performed in 0% to 30% and 0% to 25%, respectively. The modified Harris Hip Score was the most widely used patient-reported outcome measure and suggested that labral reconstruction was not inferior to labral debridement/segmental resection. CONCLUSIONS: Clinical outcomes after labral debridement/segmental resection versus labral reconstruction were found to be comparable. In the setting of unsalvageable labral pathology, labral reconstruction was used more frequently as a revision option whereas debridement may be more commonly used in the index setting. LEVEL OF EVIDENCE: Level IV, systematic review of Level I, III, and IV studies.

Influence of capsular repair versus unrepaired capsulotomy on 2-year clinical outcomes after arthroscopic hip preservation surgery.

PURPOSE: The primary objective of this study was to determine whether capsular management technique influences clinical outcomes at a minimum of 2 years after arthroscopic hip preservation surgery. METHODS: A retrospective review of prospectively collected data was conducted to determine the relative influence of 2 capsular management strategies on clinical outcomes: unrepaired capsulotomy (group A) and capsular repair (group B). Four hundred three patients who had undergone arthroscopic hip preservation surgery met the inclusion criteria and had 2-year outcome data available. All patients completed 4 patient-reported outcome (PRO) questionnaires preoperatively and at a minimum of 2 years' follow-up. These included the Hip Outcome Score-Activities of Daily Living (HOS-ADL) and Hip Outcome Score-Sport-Specific Subscale (HOS-SSS) subsets, Non-Arthritic Hip Score (NAHS), and modified Harris Hip Score (mHHS). RESULTS: Group A included 235 patients and group B, 168. The mean age of all patients at final follow-up was 36.9 years. Patients in group A were significantly older (42.3 years v 29.4 years, P < .0001) and had a significantly higher body mass index (26.8 kg/m(2)v 22.9 kg/m(2), P < .0001) compared with group B. In addition, female patients were more likely than male patients to undergo capsular repair (136 female patients v 32 male patients, P < .0001). Patients in group A also showed greater chondral damage by acetabular labrum articular disruption classification (P = .0081) and reduced preoperative PROs (HOS-ADL of 60.5 v 66.0, P = .087; HOS-SSS of 37.0 v 46.4, P = .0002; NAHS of 54.6 v 62.2, P < .0001; mHHS of 58.7 v 64.4, P = .0009; and visual analog scale score of 6.3 v 5.84, P = .028). All PROs showed statistically significant improvements for both groups at a minimum follow-up of 2 years (HOS-ADL, 60.5 to 82.2 in group A and 66 to 86.1 in group B; HOS-SSS, 36.9 to 67.3 and 46.4 to 71.2, respectively; NAHS, 54.6 to 79 and 62.2 to 82.8, respectively; visual analog scale score, 6.3 to 3.1 and 5.8 to 2.9, respectively; and mHHS, 58.7 to 81 and 64.4 to 83.8, respectively; P < .0001 for all differences). Furthermore, group B showed greater overall improvements than group A for the HOS-ADL (P = .03) and NAHS (P = .03) on uncorrected univariate analysis, but significance was lost once we controlled for confounding variables. CONCLUSIONS: Arthroscopic capsular repair, used in conjunction with arthroscopic hip preservation surgery, appears to be safe and did not negatively influence clinical outcomes in this study. When confounding variables were controlled for, the use of capsular repair did not show clinically relevant superiority over the use of unrepaired capsulotomy. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Cumulative Radiation Exposure to Patients Undergoing Arthroscopic Hip Preservation Surgery and Occupational Radiation Exposure to the Surgical Team.

PURPOSE: To quantify cumulative radiation exposure in patients undergoing arthroscopic hip preservation surgery and occupational exposure to operating room (OR) personnel during such surgery; a secondary objective of this study was to identify factors affecting radiation exposure in patients undergoing hip arthroscopy. METHODS: Radiation exposure from all preoperative and intraoperative imaging studies was determined for 52 patients undergoing hip arthroscopy. Cumulative and effective radiation doses were calculated and correlated with pathology and body mass index (BMI). Badge dosimeters were worn by OR personnel to measure cumulative occupational exposure. A highly sensitive portable ion chamber was used to evaluate the radiation scatter during surgery performed on a high-BMI patient and a low-BMI patient to reflect a "worst-case scenario" and "best-case scenario," respectively. RESULTS: Forty-three patients underwent procedures for femoroacetabular impingement (FAI) and 9 underwent procedures for soft-tissue pathologies (ST). The median cumulative exposure was 8.6 mGy and 5.0 mGy for FAI patients and ST patients, respectively (P = .01). The cumulative effective radiation dose was 490 mrem and 350 mrem for FAI patients and ST patients, respectively (P = .47). BMI significantly correlated with cumulative exposure (P = .0004) and trended toward significance with cumulative effective dose (P = .073). OR staff cumulative occupational exposure was low (9 mrem for the surgeon). Ion chamber data showed that increasing patient BMI resulted in increased occupational exposure. CONCLUSIONS: The median cumulative effective radiation dose to patients undergoing arthroscopic hip preservation surgery is 490 mrem and results in an excess lifetime risk of death from cancer of 0.025%. Greater BMI correlates with increased cumulative radiation exposure and may increase risk to OR personnel. Occupational exposure to the surgical team from hip arthroscopy ranges from 7 to 9 mrem per 50 hip arthroscopies (+0.0005% excess lifetime risk of death from cancer). LEVEL OF EVIDENCE: Level IV, diagnostic.

Hip anatomic variants that may mimic abnormalities at MRI: labral variants.

OBJECTIVE: Normal anatomic variants of the acetabular labrum are observed on MR images and include labral variants, several sublabral sulci, and perilabral sulcus. Because variants can be misidentified as labral abnormalities such as labral tears, the radiologist needs to avoid the pitfall of mistaking variants as abnormalities. CONCLUSION: The hip has multiple anatomic variants that can mimic abnormalities at hip MRI. The labrum has several anatomic variants that can be confused with true labral tears.

Hip anatomic variants that may mimic pathologic entities on MRI: nonlabral variants.

OBJECTIVE: The hip has several anatomic variants that may be mistaken for pathologic abnormalities. The radiologist needs to be able to distinguish these variants from true abnormalities. In this review, we present nonlabral variants of the hip that can be seen on MRI. CONCLUSION: The hip has multiple anatomic variants that may mimic disease on hip MRI. Like labral variants, nonlabral variants can be confused for true abnormalities.

Arthroscopic capsulotomy, capsular repair, and capsular plication of the hip: relation to atraumatic instability.

PURPOSE: The purpose of this systematic review was to critically evaluate the available literature exploring the role of the hip joint capsule in the normal state (stable) and pathologic states (instability or stiffness). Furthermore, we examined the various ways that arthroscopic hip surgeons address the capsule intraoperatively: (1) capsulotomy or capsulectomy without closure, (2) capsulotomy with closure, and (3) capsular plication. METHODS: Two independent reviewers (B.D.G. and B.G.D.) performed a systematic review of the literature using PubMed and the reference lists of related articles by means of defined search terms. Relevant studies were included if these criteria were met: (1) written in English, (2) Levels of Evidence I to V, (3) focus on capsule and its role in hip stability, and (4) human studies and reviews. Articles were excluded if they evaluated (1) total hip arthroplasty constructs using bony procedures or prosthetic revision, (2) developmental dysplasia of the hip where reorientation osteotomies were used, (3) syndromic instability, and (4) traumatic instability with associated bony injury. RESULTS: By use of the search method described, 5,085 publications were reviewed, of which 47 met appropriate criteria for inclusion in this review. Within this selection group, there were multiple publications that specifically addressed more than 1 of the inclusion criteria. Relevant literature was organized into the following areas: (1) capsular anatomy, biomechanics, and physiology; (2) the role of the capsule in total hip arthroplasty stability; (3) the role of the capsule in native hip stability; and (4) atraumatic instability and capsulorrhaphy. CONCLUSIONS: As the capsuloligamentous stabilizers of the hip continue to be studied, and their role defined, arthroscopic hip surgeons should become facile with arthroscopic repair or plication techniques to restore proper capsular integrity and tension when indicated. LEVEL OF EVIDENCE: Level IV, systematic review.

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.

The surgical destabilization of the abductor muscle leads to development of instability-associated hip osteoarthritis in mice.

Osteoarthritis (OA) of the hip is a common and debilitating painful joint disease. However, there is paucity of surgically induced hip OA models in small animals that allow scientists to study the onset and progression of the disease. A growing body of evidence indicates a positive association between periarticular myotendinous pathology and the development of hip OA. Thus, in the current study, we aimed to establish a novel mouse instability-associated hip OA model via selective injury of the abductor complex around the hip joint. C57BL6/J mice were randomized to sham surgery or abductor injury, in which the myotendinous insertion at the third trochanter and greater trochanter were surgically detached. Mice were allowed free active movement until they were sacrificed at either 3 weeks or 20 weeks post-injury. Histologic analyses and immunohistochemical staining of the femoral head articular cartilage were performed, along with microCT (µCT) analysis to assess subchondral bone remodeling. We observed that mice receiving abductor injury exhibited significantly increased instability-associated OA severity with loss of proteoglycan and type II collagen staining compared to sham control mice at 20 weeks post-surgery, while comparable matrix metalloproteinase 13 expression was observed between injury and sham groups. No significant differences in subchondral bone remodeling were found after 3 or 20 weeks following injury. Our study further supports the link between abductor dysfunction and the development of instability-associated hip OA. Importantly, this novel surgically induced hip OA mouse model may provide a valuable tool for future investigations into the pathogenesis and treatment of hip OA.

Whole-genome RNA sequencing identifies distinct transcriptomic profiles in impingement cartilage between patients with femoroacetabular impingement and hip osteoarthritis.

Femoroacetabular impingement (FAI) has a strong clinical association with the development of hip osteoarthritis (OA); however, the pathobiological mechanisms underlying the transition from focal impingement to global joint degeneration remain poorly understood. The purpose of this study is to use whole-genome RNA sequencing to identify and subsequently validate differentially expressed genes (DEGs) in femoral head articular cartilage samples from patients with FAI and hip OA secondary to FAI. Thirty-seven patients were included in the study with whole-genome RNA sequencing performed on 10 gender-matched patients in the FAI and OA cohorts and the remaining specimens were used for validation analyses. We identified a total of 3531 DEGs between the FAI and OA cohorts with multiple targets for genes implicated in canonical OA pathways. Quantitative reverse transcription-polymerase chain reaction validation confirmed increased expression of FGF18 and WNT16 in the FAI samples, while there was increased expression of MMP13 and ADAMTS4 in the OA samples. Expression levels of FGF18 and WNT16 were also higher in FAI samples with mild cartilage damage compared to FAI samples with severe cartilage damage or OA cartilage. Our study further expands the knowledge regarding distinct genetic reprogramming in the cartilage between FAI and hip OA patients. We independently validated the results of the sequencing analysis and found increased expression of anabolic markers in patients with FAI and minimal histologic cartilage damage, suggesting that anabolic signaling may be increased in early FAI with a transition to catabolic and inflammatory gene expression as FAI progresses towards more severe hip OA. Clinical significance:Cam-type FAI has a strong clinical association with hip OA; however, the cellular pathophysiology of disease progression remains poorly understood. Several previous studies have demonstrated increased expression of inflammatory markers in FAI cartilage samples, suggesting the involvement of these inflammatory pathways in the disease progression. Our study further expands the knowledge regarding distinct genetic reprogramming in the cartilage between FAI and hip OA patients. In addition to differences in inflammatory gene expression, we also identified differential expression in multiple pathways involved in hip OA progression.

Use of Area Deprivation Index to Predict Minimal Clinically Important Difference for Patient Reported Outcomes Measurement Information System After Arthroscopic Rotator Cuff Repair.

BACKGROUND: Socioeconomic disparities correlate with worse outcomes after arthroscopic rotator cuff repair. However, use of a surrogate to describe socioeconomic disadvantage has been a challenge. The Area Deprivation Index (ADI) is a tool that encompasses 17 socioeconomic variables into a single metric based on census location. HYPOTHESIS: Higher ADI would result in a worse minimal clinically important difference (MCID) for the Patient Reported Outcomes Measurement Information System (PROMIS) and have less improvement in range of motion (ROM) following arthroscopic rotator cuff repair (ARCR). STUDY DESIGN: Cohort study; Level of evidence, 3. METHOD: A retrospective review was performed for patients who underwent arthroscopic rotator cuff repair. Patients in the most socioeconomically disadvantaged quartile (ADIHigh) were compared with the least disadvantaged quartile (ADILow) in the ability to reach MCID. Demographic and surgical features were assessed for attainment of MCID. RESULTS: In total 1382 patients were identified who underwent ARCR, of which a total of 306 patients met final inclusion criteria. A higher percentage of patients within the ADIHigh cohort identified as "Black" or "other" race and had government-issued insurance compared with the ADILow cohort (P < .05). The ADIHigh cohort had significantly worse postoperative forward flexion compared with the ADILow cohort (145.0°± 32.5° vs 156.3°± 23.4°; P = .001) despite starting with comparable preoperative ROM (P = .17). Logistic regression showed that ADI was the only variable significant for predicting achievement of MCID for all 3 PROMIS domains, with the ADIHigh cohort having significantly worse odds of achieving MCID Physical Function (odds ratio [OR], 0.31; P = .001), Pain Interference (OR, 0.21; P = .001), and Depression (OR, 0.28; P = .001). Meanwhile, age, sex, body mass index, and smoking history were nonsignificant. Moreover, "other" for race and Medicare insurance were significant for achievement of MCID Depression but not Physical Function or Pain Interference. Finally, ADI was the main feature for predictive logistic regression modeling. CONCLUSION: ADI served as the only significant predictor for achieving MCID for all 3 PROMIS domains after arthroscopic rotator cuff repair. Patients who face high levels of socioeconomic disadvantage have lower rates of achieving MCID. In addition, patients with greater neighborhood disadvantage demonstrated significantly worse improvement in active forward flexion. Further investigation is required to understand the role of ADI on physical therapy compliance and to identify the barriers that prevent equitable postoperative care.

Effect of Insurance Reimbursement Status on Pre- and Postoperative Patient-Reported Outcomes Measurement Information System (PROMIS) Scores After Arthroscopic Rotator Cuff Repair.

BACKGROUND: Previous studies reported inferior patient-reported outcomes (PROs) after arthroscopic rotator cuff repair for patients receiving workers' compensation (WC) relative to patients with commercial insurance. The extent to which alternative insurance reimbursement, including Medicaid and Medicare, influences outcomes after arthroscopic rotator cuff repair remains understudied. HYPOTHESIS: Compared with patients with commercial insurance reimbursement, patients with WC or government-issued reimbursement would report lower pre- and postoperative Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function (PF) scores, report higher pre- and postoperative PROMIS Depression (D) and Pain Interference (PI) scores, and experience smaller levels of improvement in all PROMIS domains with surgical intervention. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Demographic and surgical data were extracted from the medical record, and PROMIS domains were prospectively collected. Patients were divided into cohorts based on insurance reimbursement status. Differences between insurance-based cohorts for baseline variables, pre- and postoperative PROMIS scores, and change from baseline to final follow-up (delta) for PROMIS scores were evaluated using Kruskal-Wallis or chi-square tests. Mixed-effects linear regression models were performed to assess the influence of insurance while controlling for other variables. Survival analysis was performed to determine time to achieve minimal clinically important difference (MCID) for each PROMIS domain per cohort. RESULTS: 1252 patients underwent arthroscopic rotator cuff repair, met inclusion criteria, and completed PROMIS questionnaires. Statistically significant differences were noted in demographic variables including age (P < .001), sex (P < .001), ethnicity (P < .001), and body mass index (P < .001) between insurance-based cohorts. Unadjusted analysis revealed significantly higher PF scores and lower PI and D scores for the group with commercial insurance relative to those with Medicare, Medicaid, and WC at 6- and 12-month follow-up (P < .01 all comparisons), except for the Medicare versus commercial subcohort analysis for PI at 6 months (P = .28). These differences persisted for the Medicare, Medicaid, and WC groups (P < .03 all comparisons) after adjustment for confounding variables in linear regression. CONCLUSIONS: The baseline characteristics of patients undergoing arthroscopic rotator cuff repair differed based on insurance reimbursement. Patients with commercial insurance reported improved physical function, decreased pain interference, and improved mood (less depression) relative to patients with government-issued and WC insurance, with maximum improvement 6 to 12 months postoperatively. There were few significant differences between insurance groups in change of PROMIS scores from preoperative to postoperative intervals, indicating that differences in the baseline demographic and surgical characteristics of these groups accounted for differences in response to surgery.

Diagnostic intra-articular injection with provocative functional testing predicts patient-reported outcomes following hip arthroscopy: a prospective investigation.

The purpose of this study is to evaluate the predictive value of preoperative diagnostic intra-articular injections with formal provocative post-injection functional testing on patient-reported outcomes (PROs) following hip arthroscopy. Patients aged 14-40 with suspected labral pathology and/or femoroacetabular impingement were prospectively enrolled. Patients received a diagnostic intra-articular anesthetic injection then completed a battery of provocative physical function (PF) tests and were asked to rate the percentage of pain improvement. Patients completed PRO surveys preoperatively and up to 2 years postoperatively. PROs were compared between positive and negative injection response groups. Ninety-six patients received a diagnostic injection with provocative functional testing and subsequently underwent hip arthroscopy, 74 reported a positive injection response (≥75% improvement) and 22 reported a negative injection response (<75% improvement). The average postoperative follow-up was 12 months. Both groups experienced significant improvement in PROs postoperatively. A positive injection response was associated with greater improvements in hip outcome score, Non-Arthritic Hip Score, Patient-Reported Outcomes Measurement Information System (PROMIS) pain interference and PROMIS PF at final follow-up compared to a negative injection response. Similar improvements in modified Harris Hip Score, Visual Analog Scale hip pain and PROMIS depression were experienced between groups. These results indicate that diagnostic intra-articular hip anesthetic injection with provocative functional testing may be a valuable predictor of pain and PF following hip arthroscopy. However, patients with negative injection responses still experienced significant clinical improvement in their postoperative outcomes. As such, a negative injection response should not preclude patients from being surgical candidates, but their outcomes may be less predictable.