A bioactive supramolecular and covalent polymer scaffold for cartilage repair in a sheep model.

Regeneration of hyaline cartilage in human-sized joints remains a clinical challenge, and it is a critical unmet need that would contribute to longer healthspans. Injectable scaffolds for cartilage repair that integrate both bioactivity and sufficiently robust physical properties to withstand joint stresses offer a promising strategy. We report here on a hybrid biomaterial that combines a bioactive peptide amphiphile supramolecular polymer that specifically binds the chondrogenic cytokine transforming growth factor ß-1 (TGFß-1) and crosslinked hyaluronic acid microgels that drive formation of filament bundles, a hierarchical motif common in natural musculoskeletal tissues. The scaffold is an injectable slurry that generates a porous rubbery material when exposed to calcium ions once placed in cartilage defects. The hybrid material was found to support in vitro chondrogenic differentiation of encapsulated stem cells in response to sustained delivery of TGFß-1. Using a sheep model, we implanted the scaffold in shallow osteochondral defects and found it can remain localized in mechanically active joints. Evaluation of resected joints showed significantly improved repair of hyaline cartilage in osteochondral defects injected with the scaffold relative to defects injected with the growth factor alone, including implantation in the load-bearing femoral condyle. These results demonstrate the potential of the hybrid biomimetic scaffold as a niche to favor cartilage repair in mechanically active joints using a clinically relevant large-animal model.

How Strong Is the Ligamentum Teres of the Hip? A Biomechanical Analysis.

BACKGROUND: Intraarticular hip pain represents a substantial clinical challenge, with recent studies implicating lesions in the ligamentum teres as potential contributors. Even more so, damage to the ligamentum teres is particularly prevalent among young patients undergoing joint-preserving interventions. Although several studies have investigated the biomechanical attributes of the ligamentum teres, inconsistencies in reported findings and reliance on cadaveric or animal models have raised concerns regarding the extrapolation of results to clinical practice. Furthermore, there is a lack of research examining ligamentum teres biomechanics specifically within the relevant patient cohort-individuals who benefit from joint-preserving surgical interventions. QUESTIONS/PURPOSES: We sought (1) to determine the biomechanical properties (ultimate load to failure, tensile strength, stiffness, and elastic modulus) of fresh-frozen ligaments from patients undergoing surgical hip dislocation, and (2) to identify patient-specific factors that are associated with them. METHODS: This was an institutional review board-approved study on intraoperatively harvested ligamentum teres from 74 consecutive patients undergoing surgical hip dislocation for joint preservation (August 2021 to September 2022). After the exclusion of patients with previous surgery, posttraumatic deformities, avascular necrosis, slipped capital femoral epiphysis, and Perthes disease, 31 ligaments from 31 patients were analyzed. The mean age of the study group was 27 ± 8 years, and 61% (19) of participants were male. The main indication for surgery was femoroacetabular impingement. Standardized AP pelvic and axial radiographs and CT scans were performed in all patients for better radiological description of the population and to identify associated radiological factors. The ligament was thoroughly transected at its origin on the fossa acetabuli and at the insertion area on the fovea capitis and stored at -20°C until utilization. Specimens were mounted to a materials testing machine via custom clamps that minimized slippage and the likelihood of failure at the clamp. Force-displacement and stress-strain curves were generated. Ultimate failure load (N), tensile strength (MPa), stiffness (N/mm), and elastic modulus (MPa) were determined. Using a multivariate regression analysis and a subgroup analysis, we tested demographic, degenerative, and radiographic factors as potential associated factors. RESULTS: The ligamentum teres demonstrated an ultimate load to failure of 126 ± 92 N, and the tensile strength was 1 ± 1 MPa. The ligaments exhibited a stiffness of 24 ± 15 N/mm and an elastic modulus of 7 ± 5 MPa. After controlling for potential confounding variables like age, fossa/fovea degeneration, and acetabular/femoral morphologies, we found that female sex was an independent factor for higher tensile strength, stiffness, and elastic modulus. Excessive femoral version was independently associated with lower load to failure (HR 122 [95% CI 47 to 197]) and stiffness (HR 15 [95% CI 2 to 27]). Damage to the acetabular fossa was associated with reduced load to failure (HR -93 [95% CI -159 to -27]). CONCLUSION: Overall, the ligamentum teres is a relatively weak ligament. Sex, degeneration, and excessive femoral version are influencing factors on strength of the ligamentum teres. The ligamentum teres exhibits lower strength compared with other joint-stabilizing ligaments, which calls into question its overall contribution to hip stability. CLINICAL RELEVANCE: Young patients undergoing hip-preserving surgery are the population at risk for ligamentum teres lesions. Baseline values for load to failure, tensile strength, elastic modulus, and stiffness are needed to better understand those lesions in this cohort of interest.

Editorial Commentary: Iliotibial Band Autograft Is a Safe and Effective Technique for Hip Labral Reconstruction.

Hip labral reconstruction is indicated for hypoplastic, ossified, or irreparable labral tears in the primary and revision settings. Arthroscopic reconstruction for insufficient labral tissue requires advanced surgical techniques to restore hip biomechanics and re-establish the suction seal. With the growing number of arthroscopic hip procedures being performed, this is an increasingly familiar scenario. In our experience, the iliotibial band (ITB) autograft provides a safe and effective technique for labral reconstruction at 10-year clinical follow-up. Although the harvest requires an additional incision, the graft is incredibly versatile and can be harvested at any size to address the labral deficiency. Despite the concerns for donor-site morbidity, our extensive experience shows this is incredibly rare. In addition, concomitant pathology, such as greater trochanteric bursitis, can be addressed through this incision. Other grafts can be used for labral reconstruction, such as the indirect head of the rectus femoris tendon, but this is often limited to smaller labral defects less than 1 cm. ITB autograft shows excellent mid- to long-term outcomes, and second-look surgeries show excellent incorporation of the ITB autograft. And, in contrast to allograft, autograft tissue has demonstrated lower revision rates. The type of autograft used is per surgeon discretion based on experience and preference. In our hands, ITB is optimal due to proven effectiveness, durability, versatility, and limited donor-site morbidity.

Magnetic Resonance Imaging Approximates Labral Width at the 9-, 12-, and 3-O'Clock Positions in the Setting of Revision Hip Arthroscopy.

PURPOSE: To compare preoperative magnetic resonance imaging (MRI) and intraoperative measurements of labral width and determine whether MRI can reliably predict labral width in the setting of revision surgery. METHODS: Patients who underwent revision hip arthroscopy with labral repair performed by a single surgeon from January 2008 to December 2015 were identified retrospectively from a prospectively collected database. The width of the labrum was measured intraoperatively at the time of surgery. Two orthopaedic surgeons performed labral width measurements on MRI scans at 3 standardized locations using the clock-face method. Interobserver and intraobserver reliabilities were calculated, and comparisons between intraoperatively measured labral widths and MRI measurements were performed. RESULTS: Fifty-eight patients who underwent revision hip arthroscopy were enrolled in the study. The average labral width measurements at the 3-, 12-, and 9-o'clock positions were 7.4 mm (standard deviation [SD], 1.2 mm), 7.5 mm (SD, 1.4 mm), and 6.6 mm (SD, 1.2 mm), respectively, on MRI compared with 6.7 mm (SD, 2.1 mm), 6.5 mm (SD, 2.5 mm), and 7.0 mm (SD, 1.9 mm), respectively, when measured intraoperatively. The average intraoperative measurements were smaller than the MRI measurements at the 3-o'clock (P = .03) and 12-o'clock (P = .01) positions. The inter-rater intraclass correlation coefficients between the 2 surgeons exhibited good agreement (0.612) at the 3-o'clock position, fair agreement (0.498) at the 12-o'clock position, and poor agreement (0.171) at the 9-o'clock position. The positive predictive values of the MRI measurements were 72% at the 3-o'clock position, 68% at the 12-o'clock position, and 88% at the 9-o'clock position for identifying a labral width of 6 mm or greater. CONCLUSIONS: The results of this study show that MRI-measured labral width and actual labral width measured at the time of revision arthroscopy are usually within 1 mm of each other. LEVEL OF EVIDENCE: Level II, diagnostic study investigating diagnostic test.

Improved Functional Outcomes of Combined Hip Arthroscopy and Periacetabular Osteotomy at Minimum 2-Year Follow-Up.

PURPOSE: To evaluate patient-reported outcomes (PROs) and survivorship at minimum 2-year follow-up after combined hip arthroscopy and periacetabular osteotomy (PAO) performed in the setting of a single anesthetic event. METHODS: Patients who underwent combined hip arthroscopy (M.J.P.) and PAO (J.M.M.) between January 2017 and June 2020 were identified. Preoperative and minimum 2-year postoperative PROs including Hip Outcome Score-Activities of Daily Living (HOS-ADL), HOS-Sport, modified Harris Hip Score (mHHS), Western Ontario and McMaster Universities Osteoarthritis Index, 12-Item Short Form Survey Mental Component Scores (SF-12 MCS), and 12-Item Short Form Survey Physical Component Score were collected and compared in addition to revision rate, conversion to total hip arthroplasty (THA), and patient satisfaction. RESULTS: Twenty-four of 29 patients (83%) eligible for the study were available for 2-year minimum follow-up with a median follow-up time of 2.5 years (range, 2.0-5.0). There were 19 females and 5 males with mean age of 31 ± 12 years. Mean preoperative lateral center edge angle was 20° ± 5° and alpha angle was 71° ± 11°. One patient underwent reoperation for removal of a symptomatic iliac crest screw at 11.7 months after operation. Two patients, a 33-year-old woman and a 37-year-old man, were converted to THA at 2.6 and 1.3 years, respectively, following the combined procedure. Both patients had a Tönnis grade of 1 on radiographs, as well as bipolar Outerbridge grade III/IV defects requiring microfracture of the acetabulum. For patients who did not convert to THA (n = 22), there was significant improvement from before to after surgery for all scores (P < .05) except SF-12 MCS. The minimal clinically significant difference and patient-acceptable symptom state rates for HOS-ADL, HOS-Sport, and mHHS were 72%, 82%, 86%, and 95%, 91%, and 95%, respectively. Median patient satisfaction was 10 (range, 4 to 10). CONCLUSIONS: Single-stage combined hip arthroscopy with periacetabular osteotomy for patients with symptomatic hip dysplasia results in improvement in PROs and arthroplasty free survivorship of 92% at median 2.5 year follow-up. LEVEL OF EVIDENCE: Level IV, case series.

Hip Arthroscopy Improves Outcomes With Moderate Conversion to Total Hip Arthroplasty Rates in Patients Aged 50 Years or Older: A Systematic Review.

PURPOSE: The purpose of this systematic review was to assess the indications, outcomes, and complications of hip arthroscopy in individuals 50 years of age or older over the past 5 years. METHODS: The electronic databases PUBMED, MEDLINE, and EMBASE were searched on March 3, 2022, for studies assessing the use of primary hip arthroscopy for patients aged 50 years or older from the past 5 years. The Methodological Index for Non-randomized Studies (MINORS) was used to assess study quality. Data are presented descriptively. RESULTS: Overall, 17 studies were included, consisting of 6,696 patients (37.5%) with a mean age of 61.4 ± 5.0 years and a median follow-up of 24 months (range: 1.4-70.1). Indications for hip arthroscopy in patients aged 50 years or older were unspecified/undefined (93.8%), mixed pathology (i.e., combined femoroacetabular impingement [FAI], labral tear, osteoarthritis, etc.) (2.7%), and FAI (2.6%). Eleven studies demonstrated significant improvement in functional outcome scores from baseline to final follow-up. Of the 6 studies that compared outcomes across multiple age groups, 3 demonstrated significantly worse functional outcomes, and 2 demonstrated significantly higher rates of conversion to THA for older patients compared to younger patients. Lastly, the overall complication rates ranged from 0 to 38.3%. The rate of conversion to THA ranged from 0 to 34.6%, occurring between 6 and 60 months postoperatively. CONCLUSIONS: Hip arthroscopy for patients aged 50 years or older yields significant improvements in patient-reported outcomes postoperatively compared to baseline, with a moderate rate of conversion to THA (range: 0 to 34.6%). Clinicians should consider patient history (e.g., imaging, comorbidities, etc.) and values when electing for hip arthroscopy in the older population. LEVEL OF EVIDENCE: IV, systematic review of Level III and IV studies.

Timing From Symptom Onset to Hip Arthroscopy Does Not Affect Patient-Reported Outcome Measures for the Treatment of Femoroacetabular Impingement in Adolescent Patients.

PURPOSE: To evaluate symptom duration and its relationship to patient-reported outcomes (PROs) and survivorship after hip arthroscopy in adolescents. METHODS: Patients ≤18 at time of primary hip arthroscopy for femoroacetabular impingement (FAI) between January 2011 and September 2018 were included. Exclusion criteria consisted of history of previous ipsilateral hip surgery, presence of osteoarthritis or dysplasia on preoperative radiographs, previous hip fracture, or history of slipped capital femoral epiphysis or Legg-Calve-Perthes disease. Minimum 2-year PROs (modified Harris Hip Score, Hip Outcome Score [HOS]-Activities of Daily Living, HOS-Sport Scale, Short Forms 12 [SF-12]), minimum clinically significant difference (MCID) and patient-acceptable symptom state (PASS) rates, and revision surgery rates were compared based on symptom duration. RESULTS: Two-year minimal follow-up was obtained for 111 patients (134 hips) (80%), including 74 females and 37 males with a mean age of 16.4 ± 1.1 (range 13.0-18.0). The mean symptom duration was 17.2 ± 15.2 months (range 43 days to 6.0 years). Ten patients (11 hips), 6 females (7 hips) and 4 males, required revision surgery at an average of 2.3 ± 1.0 years (range 0.9-4.3 years). At a mean follow-up of 4.8 ± 2.2 years (range 2-10 years), there were statistically significant improvements in all PROs (P < .05 for all). Symptom duration showed no significant correlation to post-operative scores (correlation coefficient range -0.162 to -0.078, P > .05 for all). Symptom duration ≤12 months versus >12 months or as a continuous variable was not a predictor for requiring revision surgery or achieving MCID/PASS (95% confidence interval crosses 1 for all). CONCLUSIONS: In an adolescent cohort of symptomatic FAI patients who underwent hip arthroscopy, there is no difference in PRO measures when analyzing symptom duration by arbitrary time intervals or as a continuous variable. LEVEL OF EVIDENCE: Level IV, case series.

The effects of fisetin on bone and cartilage: A systematic review.

As the worldwide population progresses in age, there is an increasing need for effective treatments for age-associated musculoskeletal conditions such as osteoporosis and osteoarthritis (OA). Fisetin, a natural flavonoid, has garnered attention as a promising pharmaceutical option for treating or delaying the progression of osteoporosis and OA. However, there is no systematic review of the effects of fisetin on bone and cartilage. The aim of this review is to report the latest evidence on the effects of fisetin on bone and cartilage, with a focus on clinical significance. The PubMed, Embase, and Cochrane Library databases were searched up to December 9th 2021 to evaluate the effects of fisetin on bone and cartilage in in vitro studies and in vivo preclinical animal studies. The risk of bias, quality, study design, sample characteristics, dose and duration of fisetin treatment, and outcomes of the 13 eligible studies were analyzed in this systematic review. Qualitative evaluation was conducted for each study due to differences in animal species, cell type, created disease model, dose and duration of fisetin treatment, and time between intervention and assessment among the eligible studies. The beneficial effects of fisetin on osteoporosis have been demonstrated in in vitro and in vivo preclinical studies across animal species. Similarly, the beneficial effects of fisetin on OA have been demonstrated in in vivo preclinical animal studies, but the reports on OA are still limited. Fisetin, a natural supplement can be use in orthobiologics treatment, as adjuvant to orthopaedic surgery, to improve clinical outcome.

Surgical Treatment of Acetabular Dysplasia With Labral Tears.

Acetabular dysplasia results in abnormal forces across the hip joint and can result in both labral tears and cartilage degeneration. A continuum exists from classic dysplasia to normal acetabular morphology. Diagnosis is aided by several radiographic measurements and parameters including a lateral center edge angle of less than 20°, an anterior center edge angle of less than 20°, a Sharp's angle of greater than 42°, and a Tonnis angle of greater than 10°, or version abnormalities. When patients with acetabular dysplasia present with intra-articular hip pain, skeletal maturity, and preserved radiographic joint space, a periacetabular osteotomy (PAO) is considered as a surgical treatment option when conservative measures have failed. The Bernese PAO was developed in 1984 as a way for reorienting the acetabulum to restore more normal femoral head coverage and orientation. The long-term results of this procedure have been promising with 10-year and 20-year survivorships of approximately 85% and 60%, respectively. When dysplasia is coupled with a labral tear or other intra-articular pathology including focal chondral damage, ligamentum teres tears, or capsular defects, hip arthroscopy and PAO are performed. Although there is a paucity in the literature of the long-term evidence for the combined procedure, early results indicate improved patient reported outcome measures. Appropriate treatment of borderline hip dysplasia remains controversial.

Editorial Commentary: Postoperative Alpha Angle and Return to Sport: One Piece of the Puzzle.

Return-to-sport rates following arthroscopic treatment of femoroacetabular impingement are high; however, the predictors of failure to return to sport must be elucidated. Recent data suggest that the postoperative alpha angle may be a significant predictor of return to sport in athletes, despite the fact that the role of radiographic measurements on postoperative outcomes is debated in the literature. Nonetheless, it is incumbent on surgeons to fully understand the unique biomechanics of the hip in each sport and consider each patient's unique anatomy when undertaking cam resection. Recreation of the motion at-risk during a careful intraoperative dynamic examination is imperative to ensure that all areas of impingement have been eradicated while attentively avoiding over-resection. While the postoperative alpha angle is an important metric for surgeons to keep in mind, it may only represent one piece of the puzzle.

Lower Center Edge Angle and Bioipolar Cartilage Lesions Are Associated With Conversion to Hip Arthroplasty Within 2 Years Following Hip Arthroscopy: A Matched Cohort Analysis.

PURPOSE: The purpose of this study was to determine whether radiographic parameters, intraoperative findings, patient-reported outcome measures, or intraoperative interventions that were performed differentiate those patients with >2 mm of joint space who convert under two years to total hip arthroplasty (THA) after undergoing hip arthroscopy for femoroacetabular impingement (FAI) when compared to those converting after 2 years. METHODS: Included in this study were patients who underwent conversion to THA within 2 years of primary hip arthroscopy from a prospectively collected patient registry from 2007 to 2017. Patients who underwent early conversions to arthroplasty were matched 1:1 with patients who converted after 2 years, based upon age and gender. Preoperative outcome scores were collected, including Short Form-12, modified Harris Hip Score, and Hip Outcome Score. Additionally, variables from the preoperative radiographic evaluation, surgical findings, and procedures performed were also compared. RESULTS: Forty-nine patients were included in the early conversion group and were matched with 49 patients in the later conversion group. Patients with lateral center edge angles of less than 25° were more likely to be in the early failure group [OR: 3.9; 95% CI: 1.01 to 15]. Patients with unipolar chondral defects on either the femoral (P = .128) or acetabular side (P = .656) were not at increased odds for early conversion compared to later conversion; however, those with bipolar chondral lesions at the time of surgery had increased odds of early conversions [OR: 3.3; 95% CI: 1.4 to 8] (P = .01). Neither surgical treatment nor preoperative patient-reported outcome measures were associated with early conversion. CONCLUSIONS: In patient with >2 mm of joint space, lateral center edge angles of less than 25° and those with bipolar articular cartilage lesions seen at the time of hip arthroscopy are at increased risk for conversion to total hip arthroplasty within two years. LEVEL OF EVIDENCE: Level III, retrospective comparison study.

Arthroscopic Hip Capsular Reconstruction Using Iliotibial Band Allograft as a Salvage Option for Unrepairable Capsular Defects Demonstrates Good Survivorship and Improved Patient-Reported Outcomes.

PURPOSE: To describe patient outcomes 3 to 5 years after arthroscopic hip capsule reconstruction. METHODS: Between January 2007 and December 2016, patients aged 18 to 50 years who underwent arthroscopic hip capsular reconstruction using an Iliotibial band allograft by the senior author and had minimum of 3-year follow-up were identified. Patients were excluded if they had previous open hip surgery, advanced osteoarthritis (Tönnis grade >2), significant acetabular dysplasia (lateral center edge angle <20°), avascular necrosis, or Legg-Calve-Perthes disease. Outcome scores including the Hip Outcome Score (HOS)-Activities of Daily Living scale, modified Harris Hip Score, HOS-Sports scale, SF-12, and Western Ontario & McMaster Universities Osteoarthritis Index were compared in addition to failure rate, revision rate, and patient satisfaction rate with the outcome (range, 1-10). All patients were assessed by the senior author pre- and postoperatively. RESULTS: Thirty-nine patients met the inclusion criteria. The mean age of the cohort was 32 ± 10 years, with 6 male and 33 female patients. The average number of previous hip arthroscopy surgeries was 2 ± 1. Six patients (15%) converted to total hip arthroplasty at an average of 2.1 years (range 7 months to 6 years) following capsular reconstruction. Four patients required revision hip arthroscopy after the arthroscopic capsular reconstruction. All arthroscopic revisions occurred in female patients with the primary intraoperative finding of capsulolabral adhesions at the time of revision. At mean follow-up of 4.3 years (range 3-6.8 years), the 29 patients who did not require subsequent surgery had significant improvements from preoperatively to postoperatively in HOS-Activities of Daily Living and HOS-Sport with 90% reaching minimal clinically important difference. All other scores showed significant improvement. Survival for patients not requiring total hip arthroplasty was 86% at 3 years, with a mean survival of 5.7 years (95% confidence interval 4.97-6.4). CONCLUSIONS: Arthroscopic hip capsular reconstruction with iliotibial band allograft is a successful treatment option for patients with symptomatic capsular defects, demonstrating improved patient-reported outcomes maintained at mean follow-up time of 4 years. This technique offers restoration of the anatomic structure and function of the capsular ligaments to improve pain and instability. LEVEL OF EVIDENCE: IV, case series.

Criteria for the Operating Room Confirmation of the Diagnosis of Hip Instability: The Results of an International Expert Consensus Conference.

PURPOSE: The purpose of this study was to establish an international expert consensus on operating room findings that aid in the diagnosis of hip instability. METHODS: An expert panel was convened to build an international consensus on the operating room diagnosis/confirmation of hip instability. Seventeen surgeons who have published or lectured nationally or internationally on the topic of hip instability were invited to participate. Fifteen panel members completed a pre-meeting questionnaire and agreed to participate in a 1-day consensus meeting on May 15, 2021. A review of the literature was performed to identify published intraoperative reference criteria used in the diagnosis of hip instability. Studies were included for discussion if they reported and intraoperative findings associated with hip instability. The evidence for and against each criteria was discussed, followed by an anonymous voting process. For consensus, defined a priori, items were included in the final criteria set if at least 80% of experts agreed. RESULTS: A review of the published literature identified 11 operating room criteria that have been used to facilitate the diagnosis of hip instability. Six additional criteria were proposed by panel members as part of the pre-meeting questionnaire. Consensus agreement was achieved for 8 criteria, namely ease of hip distraction under anesthesia (100.0% agreement), inside-out pattern of chondral damage (100.0% agreement), location of chondral damage on the acetabulum (93.3% agreement), pattern of labral damage (93.3% agreement), anteroinferior labrum chondral damage (86.7% agreement), perifoveal cartilage damage (97.6% agreement), a capsular defect (86.7% agreement), and capsular status (80.0% agreement). Consensus was not achieved for 9 items, namely ligamentum teres tear (66.7% agreement), arthroscopic stability tests (46.7% agreement), persistent distraction after removal of traction (46.7% agreement), findings of examination under anesthesia (46.7% agreement), the femoral head divot sign (40.0% agreement), inferomedial synovitis (26.7% agreement), drive-through sign (26.7% agreement), iliopsoas irritation (26.7% agreement) and ligamentum teres-labral kissing lesion (13.3% agreement). All experts agreed on the final list of 8 criteria items reaching consensus. CONCLUSION: This expert panel identified 8 criteria that can be used in the operating room to help confirm the diagnosis of hip instability. LEVEL OF EVIDENCE: Level V expert opinion.

Editorial Commentary: Indications for Concurrent Procedures During Hip Femoroacetabular Impingement Arthroscopic Treatment.

In patients with femoroacetabular impingement (FAI), hip joint pathology often leads to an alteration of gait as well as core and pelvic muscular imbalance. Flexor, abductor, adductor, and hamstring tightness and pain are common patient-reported complaints at the time of evaluation for FAI and potential hip arthroscopy. Surgical interventions have been developed to target all of these potential issues, but the question remains whether these concurrent procedures are necessary, or whether postoperative rehabilitation and other conservative measures may better treat associated conditions. We recommend that iliotibial band release is not indicated for patients with nonsnapping extra-articular lateral hip pain and should be reserved for frank, external snapping hip. Patients with lateral hip pain that prevents them from lying on their side at night are candidates for endoscopic trochanteric bursectomy through a minimal longitudinal ITB incision. Patients with evidence of gluteus medius pathology including positive Trendelenburg test, Trendelenburg gait, or pain with resisted hip abduction are treated with either bioinductive patch gluteus medius tendon augmentation or endoscopic or open abductor repair. The challenge is determining which of these associated conditions are compensatory (i.e., will improve after the underlying hip pathology is addressed during FAI surgery), and which are pathologic (i.e., must separately be addressed at the time of surgery).

Salvage Revision Hip Arthroscopy Including Remplissage Improves Patient-Reported Outcomes After Cam Over-Resection.

PURPOSE: To evaluate outcomes of arthroscopic hip remplissage with folded iliotibial band allograft to treat cam over-resection. METHODS: Patients who underwent arthroscopic iliotibial band hip remplissage from May 2013 to April 2018 were prospectively evaluated. Pre- and postoperative patient-reported outcome scores were compared and included the 12-Item Short Form Survey (SF12) Physical Health Composite Score (PCS), SF12 Mental Health Composite Score (MCS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), modified Harris Hip Score (mHHS), and Hip Outcome Score (HOS) (Activities of Daily Living [ADL] and Sport). Postoperative Tegner Activity Scale and patient satisfaction (1-10) were also evaluated. RESULTS: Thirteen patients (2 men, 11 women) with an average age of 39.8 ± 9 years underwent arthroscopic hip remplissage with minimum 2-year and mean 3.1-year follow-up (range, 2.1-4.1 years). One hundred percent follow-up was achieved. The average number of previous surgeries was 1.38 (range, 1-3). One patient underwent total hip arthroplasty 2 years after remplissage. All 12 patients who did not undergo total hip arthroplasty had improved patient-reported outcomes after remplissage (mean scores: SF12 PCS 36 vs 42, P = .02; SF12 MCS 45 vs 51, P = .14; mHHS 45 vs 66, P < .001; minimal clinically important difference [MCID] 83%; WOMAC 42 vs 28, P < .001; HOS ADL 52 vs 69, P = .003; MCID, 67%; HOS Sport 27 vs 46, P = .015; MCID, 67%). All improvements met statistical significance, besides the SF12 MCS. Median postoperative Tegner score was 2.9. Median postoperative patient satisfaction was 7 out of 10 (range, 5-10). CONCLUSIONS: Arthroscopic hip remplissage is a successful salvage treatment option for hip instability caused by previous cam over-resection. Care must be taken during primary surgery not to over-resect the cam as patient-reported outcomes after remplissage are inferior to those undergoing primary hip arthroscopy. LEVEL OF EVIDENCE: Level IV, case series.

An Anatomic Study of the Damage to Capsular Hip Stabilizers During Subspine Decompression Using a Transverse Interportal Capsulotomy in Hip Arthroscopy.

PURPOSE: To quantify the damage to the soft tissue stabilizers of the hip after a transverse interportal capsulotomy and subspine trimming in hip arthroscopy. METHODS: Eight human cadaveric hemipelvises underwent hip arthroscopy through a transverse interportal capsulotomy. Arthroscopic subspine trimming performed on all specimens was classified according to an anatomic index. The width of the proximal capsule was measured before and after subspine trimming. The extent of damage to the iliofemoral ligament (IFL) after dissection was recorded. Potential damage to pericapsular structures was assessed by measuring the distance between the capsulotomy and rectus femoris and iliocapsularis muscle with an electronic caliper. RESULTS: In all specimens, ≥50% of the width of the IFL was damaged. The subspine trimming was successfully performed in 7 of 8 specimens (87.5%) according to the proposed index. The sizes of the trimmed bone area measured in the anteroposterior and proximal-distal axis were 21.2 ± 7.5 and 13.1 ± 9 mm, respectively (mean ± standard deviation). The width of the proximal capsule at the anterior and posterior corner of the capsulotomy was 19.8 ± 5.2 and 11.8 ± 1.7 mm, respectively. After subspine trimming, the mean width of the anterior and posterior proximal capsular attachments was 6.4 ± 1.4 and 7.0 ± 1.6 mm, respectively. On average, 13.4 mm of anterior capsule was damaged after anterior inferior iliac spine trimming, versus 4.7 mm of the posterior capsule. The distances from the capsulotomy to the rectus femoris direct and reflected head were 6.8 ± 4.9 and 6.3 ± 7.7 mm, respectively, and to the iliocapsularis muscle, 11.5 ± 7.8 mm. CONCLUSION: High rates of damage to the IFL were observed with the interportal capsulotomy. Increased tissue damage at the anterior capsule was observed after subspine trimming. The width of the proximal capsular attachment was ≥5 mm in all specimens. CLINICAL RELEVANCE: Surgeons should be aware of the potential damage to the native capsule and pericapsular structures when using a transverse interportal capsulotomy for the arthroscopic subspine decompression. LEVEL OF EVIDENCE: IV: cadaveric study, case series.

Differentiation Potential of Synovial Mesenchymal Stem Cells Isolated From Hip Joints Affected by Femoroacetabular Impingement Syndrome Versus Osteoarthritis.

PURPOSE: To establish the characteristics of synovium-derived mesenchymal stem cells (MSCs) from the hip joints of patients with femoroacetabular impingement syndrome (FAIS) and osteoarthritis (OA), particularly their proliferation and differentiation potentials. We further investigated their functional differences. METHODS: Synovium samples were harvested from 21 patients with FAIS who underwent hip arthroscopic surgery and from 14 patients with OA who underwent total hip arthroplasty. The MSC number, colony-forming units, cell viability, and differentiation potential were compared. Real-time polymerase chain reaction assessed the differentiation potential into adipose, bone, and cartilage tissues. RESULTS: The number of colonies at a density of 104 at passage 0 from OA synovium was significantly greater than that from FAIS synovium (P < .01). However, their proliferation and viability were significantly lower than those of FAIS synovium cells (P = .0495). The expression of lipoprotein lipase mRNA in OA synovium cells was greater than that in FAIS synovium cells (P < .01). Meanwhile, the fraction of colonies positive for von Kossa and alkaline phosphatase staining, as well as the level of bone gamma-carboxyglutamate protein expression in OA synovium cells, were greater than those in FAIS synovium cells (P < .01). In chondrogenic pellet culture experiments, the expression of COL10A1 mRNA was lower in OA synovium than in FAIS synovium (P < .01). CONCLUSIONS: Synovial MSCs from patients with OA had greater colony numbers but less viability and proliferative potential. They also showed greater osteogenic and adipogenic potentials, whereas those from patients with FAIS showed greater chondrogenic potential. CLINICAL RELEVANCE: MSCs from patients with FAIS exhibited good potential as cell sources for stem cell therapy in case of cartilage damage in the hip joint.

Survey results from an international hip course: comparison between experts and non-experts on hip arthroscopy clinical practice and post-operative rehabilitation.

PURPOSE: The purpose of this study was to compare the clinical practices between expert and non-expert arthroscopy hip surgeons. METHODS: Registered orthopedic surgeons completed anonymous surveys during a hip arthroscopy meeting. The survey included 60 questions on physician's level of expertise, surgical anesthesia, procedures performed, hospital stay, pain control, rehabilitation and socioeconomic parameters, and the results are presented. Comparisons were made between hip arthroscopy experts (> 500 cases performed) and non-experts (≤ 500 cases performed) on aspects of patient care. RESULTS: Forty-eight (74%) surgeons responded. Forty-four questionnaires were filled out completely. There were no significant differences in recommendations between 15 (34%) hip arthroscopy experts and 29 (66%) non-experts on hip capsular management and cartilage repair techniques, use of antithrombotic prophylaxis and opioid analgesics, time of rehabilitation initiation and patient compliance factors, use of hip brace and CPM, and patient evaluation to return to sports following surgery. Surgical expertise was significantly associated with the performance of hip labral reconstruction (p = 0.016), subspine decompression (p = 0.039) and recommendation of a longer period of restricted weight bearing following the performance of microfractures (p = 0.011). There were no significant differences in clinical practice between surgeons who performed hip arthroscopy exclusively versus those who did not. CONCLUSIONS: Hip arthroscopy is a relatively new field, and clinical practice may vary among physicians based on the surgical expertise. In this study, hip arthroscopy experts agree with non-experts on most aspects of patient care. Surgical expertise was associated with performance of advanced techniques and recommendation of longer period of restricted weight bearing following performance of microfractures. This study highlights different care patterns that need to be investigated to determine which treatment results in improved patient care. LEVEL OF EVIDENCE: V.

First 100 segmental labral reconstructions compared to the most recent 100: the role of surgeon experience in decreasing conversion to total hip arthroplasty.

PURPOSE: The purpose of this study was to determine if conversion to total hip arthroplasty and patient-reported outcomes were similar in the first 100 patients who underwent segmental labral reconstruction with iliotibial band autograft compared to the most recent 100 patients. METHODS: Patients who underwent hip segmental labral reconstruction with autologous iliotibial band were evaluated preoperatively and postoperatively with a minimum 2-year follow-up. The first consecutive 100 patients (Group 1) and the most recent 100 patients (Group 2) were retrospectively compared. Conversion to total hip arthroplasty, necessity of a revision hip arthroscopy, and patient-reported outcome scores were compared. RESULTS: Overall follow-up rate (> 2 years) was 94% (Group 1 vs. Group 2, 91% vs. 96%, n.s.). Mean age of Group 1 (37 ± 12) was significantly higher than that of Group 2 (34 ± 12) (p = 0.03). In Group 2, 69 surgeries out of 100 were revision hip arthroscopies, which was significantly higher rate than Group 1 (48/100) (p = 0.003). Group 1 had significantly higher rate of conversion to THA [23% (23/100) vs. 5% (5/100), p = 0.001]. Revision hip arthroscopy was performed in 11/76 (15%) in Group 1 and in 8/95 (9%) in Group 2 (n.s.). Patient-reported outcomes scores were similar between two groups (all n.s.). Higher age and joint space ≤ 2 mm were significant risk factors of total hip arthroplasty conversion. CONCLUSION: This study showed that, with experience, fewer conversions to total hip arthroplasty were seen; however, revision rate and outcomes were similar. LEVEL OF EVIDENCE: IV.

Effect of Oral Losartan on Orthobiologics: Implications for Platelet-Rich Plasma and Bone Marrow Concentrate-A Rabbit Study.

Recent efforts have focused on customizing orthobiologics, such as platelet-rich plasma (PRP) and bone marrow concentrate (BMC), to improve tissue repair. We hypothesized that oral losartan (a TGF-ß1 blocker with anti-fibrotic properties) could decrease TGF-ß1 levels in leukocyte-poor PRP (LP-PRP) and fibrocytes in BMC. Ten rabbits were randomized into two groups (N = 5/group): osteochondral defect + microfracture (control, group 1) and osteochondral defect + microfracture + losartan (losartan, group 2). For group 2, a dose of 10mg/kg/day of losartan was administrated orally for 12 weeks post-operatively. After 12 weeks, whole blood (WB) and bone marrow aspirate (BMA) samples were collected to process LP-PRP and BMC. TGF-ß1 concentrations were measured in WB and LP-PRP with multiplex immunoassay. BMC cell populations were analyzed by flow cytometry with CD31, CD44, CD45, CD34, CD146 and CD90 antibodies. There was no significant difference in TGF-ß1 levels between the losartan and control group in WB or LP-PRP. In BMC, the percentage of CD31+ cells (endothelial cells) in the losartan group was significantly higher than the control group (p = 0.008), while the percentage of CD45+ cells (hematopoietic cells-fibrocytes) in the losartan group was significantly lower than the control group (p = 0.03).