Capsular attachment on the anterosuperior femoral head-neck junction: A hypothesis about femoroacetabular impingement.

Femoroacetabular impingement (FAI), characterized by a pathological contact between the proximal femur and acetabulum, is a common precursor of hip osteoarthritis. Cam morphology is a bony prominence that causes FAI and frequently forms on the anterosuperior femoral head-neck junction. Despite anatomical consensus regarding the femoral head-neck junction as a boundary area covered by the articular cartilage and joint capsule, it remains unclear whether the joint capsule is continuous with the anterosuperior articular cartilage. For the anatomical consideration of cam morphology formation, this study aimed to investigate the histological characteristics of the capsular attachment on the anterosuperior femoral head-neck junction, particularly focusing on the presence or absence of continuity of the joint capsule to the articular cartilage. A total of 21 anterosuperior regions (seven hips each for the 12:00, 1:30, and 3:00 positions) from seven hips (three males and four females; mean age at death, 68.7 years) were histologically analyzed in this study for quantitative evaluation of the capsular thickness using histological sections stained with Masson's trichrome, as well as qualitative evaluation of the capsular attachment. The present study showed that the joint capsule, which folded proximally to the femoral head-neck junction from the recess, exhibited a blend of the fibrous and synovial regions. Notably, it not only continued with the superficial layer of the articular cartilage, but also attached to the articular cartilage via the fibrocartilage. This continuous region was relatively fibrous with dense connective tissue running in the longitudinal direction. The capsular thickness at the recess point (mean, 1.7 ± 0.9 mm) and those at the distal end of the articular cartilage (0.35 ± 0.16 mm) were significantly greater than the control value for the most superficial layer thickness of the articular cartilage (0.019 ± 0.003 mm) (Dunnett's T3, both p-value <0.001). Based on the fibrous continuity between the joint capsule and articular cartilage and its thickness, this study suggests the anatomical possibility that some mechanical stress can be transmitted from the joint capsule to the articular cartilage at the frequent sites of cam morphology.

In vivo interrelationships between the gluteus minimus and hip joint capsule in the hip internal rotation position with flexion.

BACKGROUND: The flexion adduction internal rotation (FADIR) test is performed by the combined motions of hip flexion (with knee flexion), adduction, and internal rotation, and can often reproduce anterior hip pain consistent with an individual's presenting pain. Since it has high sensitivity for intraarticular pathology diagnosis but low specificity, understanding the extraarticular pathology that can induce anterior hip pain in the FADIR test may also be essential. This study hypothesized that the interrelationships between the joint capsule and gluteus minimus differ in individuals with and without FADIR-positive pain and aimed to elucidate the in vivo interrelationships at hip internal rotation in 90°-flexion, which is also often restricted in individuals with FADIR-positive pain. METHODS: Ten hips were included in the FADIR-positive group, and ten hips without hip pain in the FADIR test were included in a control group. Based on the ultrasound images at the four hip rotation conditions (20° and 10° external rotations, 0° external/internal rotation, and 10° internal rotation), orientation measurements of the gluteus minimus (muscle belly portion) and joint capsule were performed and quantitatively compared between the FADIR-positive and control groups. Additionally, 3 hips of 3 participants were randomly selected from each of the control and FADIR-positive groups for magnetic resonance imaging analysis. RESULTS: At 0°-external/internal and 10°-internal rotation, on ultrasound images, fibers of the gluteus minimus and joint capsule in the FADIR-positive group were significantly more oriented in the same direction than those in the control group. Magnetic resonance imaging showed that the loose connective tissue between the gluteus minimus and joint capsule was prominent at 10°-internal rotation in the control group, although this was not apparent in the FADIR-positive group. CONCLUSIONS: At hip internal rotation in 90° flexion, the muscular belly portion of the gluteus minimus and joint capsule were oriented in the same direction to a greater extent in the FADIR-positive group than in the control group owing to a morphological change in the loose connective tissue between them. The pathological changes in the loose connective tissue may inhibit smooth movement of the gluteus minimus relative to the joint capsule in individuals with FADIR-positive pain.

Losartan in Combination With Bone Marrow Stimulation Showed Synergistic Effects on Load to Failure and Tendon Matrix Organization in a Rabbit Model.

PURPOSE: To investigate the effects of combining bone marrow stimulation (BMS) with oral losartan to block transforming growth factor ß1 (TGF-ß1) on biomechanical repair strength in a rabbit chronic injury model. METHODS: Forty rabbits were randomly allocated into 4 groups (10 in each group). The supraspinatus tendon was detached and left alone for 6 weeks to establish a rabbit chronic injury model and was then repaired in a surgical procedure using a transosseous, linked, crossing repair construct. The animals were divided into the following groups: control group (group C), surgical repair only; BMS group (group B), surgical repair with BMS of the tuberosity; losartan group (group L), surgical repair plus oral losartan (TGF-ß1 blocker) for 8 weeks; and BMS-plus-losartan group (group BL), surgical repair plus BMS plus oral losartan for 8 weeks. At 8 weeks after repair, biomechanical and histologic evaluations were performed. RESULTS: The biomechanical testing results showed significantly higher ultimate load to failure in group BL than in group B (P = .029) but not compared with group C or group L. A 2 × 2 analysis-of-variance model found that the effect of losartan on ultimate load significantly depended on whether BMS was performed (interaction term F1,28 = 5.78, P = .018). No difference was found between the other groups. No difference in stiffness was found between any groups. On histologic assessment, groups B, L, and BL showed improved tendon morphology and an organized type I collagen matrix with less type III collagen compared with group C. Group BL showed the most highly organized tendon matrix with more type I collagen and less type III collagen, which indicates less fibrosis. Similar results were found at the bone-tendon interface. CONCLUSIONS: Rotator cuff repair combined with oral losartan and BMS of the greater tuberosity showed improved pullout strength and a highly organized tendon matrix in this rabbit chronic injury model. CLINICAL RELEVANCE: Tendon healing or scarring is accompanied by the formation of fibrosis, which has been shown to result in compromised biomechanical properties, and is therefore a potential limiting factor in healing after rotator cuff repair. TGF-ß1 expression has been shown to play an important role in the formation of fibrosis. Recent studies focusing on muscle healing and cartilage repair have found that the downregulation of TGF-ß1 by losartan intake can reduce fibrosis and improve tissue regeneration in animal models.

Intra-articular injection versus interscalene brachial plexus block for acute-phase postoperative pain management after arthroscopic shoulder surgery.

BACKGROUND: The minimally invasive approach of arthroscopic shoulder surgery is beneficial; however, for optimal outcomes, perioperative pain management is essential. This cross-sectional study aimed to examine the analgesic effectiveness of intra-articular injection (IA) versus interscalene brachial plexus block (ISPB) among patients treated with arthroscopic shoulder surgeries. METHODS: We reviewed 100 consecutive patients who underwent shoulder arthroscopic surgery, of whom 50 each underwent IA (February 2019─January 2020; IA group) and ISPB (October 2018─July 2019; ISPB group). The primary outcome was the postoperative pain score measured using a Wong-Baker FACES Pain Rating Scale preoperatively and at 2, 6, 12, 24, and 48 h postoperatively. We performed multiple regression analysis to examine whether IA/ISPB selection is associated with acute-phase postoperative pain and adjusted for intra-articular injection, interscalene brachial plexus block, postoperative pain management, arthroscopic shoulder surgery, IA with 10 mg of morphine previously reported prognostic factors for postoperative pain (e.g., surgical procedures, operative time, older age, and preoperative pain). Furthermore, we examined induction time, total pentazocine dosage, and total postoperative nausea and vomiting (PONV) events. RESULTS: There were no significant differences between the IA and ISPB groups in perioperative pain control during the acute-phase periods (p = 0.12, repeated analysis of variance). The difference in anesthesia method was not a prognostic factor for acute-phase postoperative pain (p = 0.11). The IA group (15.06 ± 4.00 min) had a significantly shorter mean anesthesia induction time than the ISPB group (29.23 ± 9.22 min) (p = 0.0001). There was no significant between-group difference in the total pentazocine dosage during the first 7 days (p = 0.3934) postoperatively. PONV was observed in eight (17.0%) and two (4.2%) patients in the IA and ISPB groups, respectively. There was no significant between-group difference in the PONV incidence (p = 0.1582). CONCLUSIONS: There was no significant difference in acute-phase postoperative pain management between the IA and ISPB groups. The induction time was significantly shorter in IA. IRB: Approval number: UOEHCRB20-078, IRB approval date: September 9th, 2020; study duration: October 2018 to January 2020.

Is Arthroscopic Hip Labral Repair/Reconstruction Surgery Effective for Treating Femoroacetabular Impingement in the Presence of Osteoarthritis?

OBJECTIVE: To investigate clinical outcomes after arthroscopic labral preservation surgery for femoroacetabular impingement (FAI) in the presence of osteoarthritis (OA) compared with FAI without significant OA. DESIGN: Retrospective case-control study. SETTING: Department of Orthopaedic Surgery and Sports Medicine, Hospital of Academic Institute. PATIENTS: Femoroacetabular impingement patients (n = 97; ≥35 years) undergoing arthroscopic FAI correction with labral preservation surgery from March 2009 to April 2014 were enrolled in this study. INTERVENTIONS: Patients were divided into 2 groups: FAI group (79 patients), with Tonnis grade 0 or 1, and FAI + OA group (18 patients), with Tonnis grade 2 or 3. MAIN OUTCOME MEASURES: We examined the clinical outcomes using the Modified Harris Hip Score (MHHS), Nonarthritic Hip Score (NAHS), and the conversion rate to total hip arthroplasty (THA). RESULTS: No significant differences existed between the 2 groups with respect to age, sex, follow-up period, or preoperative MHHS or NAHS. The mean MHHS and NAHS at the final follow-up were significantly lower in the FAI + OA group than in the FAI group. There was a significant difference in the rate of conversion to THA and failure between the 2 groups (THA 5% vs 50%) (failure 15% vs 67%). CONCLUSION: Patients with FAI in the presence of OA did not improve after arthroscopic labral preservation surgery and had a high conversion rate to THA. LEVEL OF EVIDENCE: Level III.

Dynamic changes of the joint capsule in relation to the zona orbicularis: An anatomical study with possible implications for hip stability mechanism.

The zona orbicularis, which comprises the inner circular fibers of the joint capsule, is vital for hip stability in distraction. Despite the proximity of the whole joint capsule to the zona orbicularis, their anatomical relationship remains unclear. The aim of this study is to investigate the characteristics of the inner side of the joint capsule comprehensively. Twelve hips from nine bodies donated to science were examined. Six and three of the donated bodies, respectively, were embalmed using 8% formalin and Thiel's method. The joint capsules in three formalin-embalmed bodies were sturied by micro-computed tomography. During formalin fixation of six hips from these three bodies, one side was maintained at hip extension and the other at flexion. The remaining three formalin-embalmed bodies were examined histologically. Micro-computed tomography images revealed that the inward protrusion of the joint capsule narrowed the articular cavity, and the ratio of its narrowest area to that of the femoral neck was less at hip extension than at hip flexion. The Thiel's method specimens showed that the inner surface of the joint capsule protruded inward toward the femoral neck during hip extension. This inward protrusion was not histologically independent of the joint capsule. The zona orbicularis was interpreted as the inward protrusion caused by dynamic change of the joint capsule, rather than the local collar. In other words, the joint capsule could change its morphology dynamically depending on the hip position.

Editorial Commentary: Mesenchymal Stem Cell Preparation Methods Affect the Properties of Shoulder Subacromial Bursa-Derived Cells.

Augmentation of mesenchymal stem cells (MSCs) from the subacromial bursa in the setting of irreparable rotator cuff tears is a powerful candidate for future regenerative medicine. However, little is known about whether the preparation technique affects the individual differences and potentials of subacromial bursa-derived MSCs. The yields obtained by chopping or cell-expansion techniques with a high-density of initial nucleated cells seem to be lower than those obtained with low-density cell-expansion techniques. Differences in cell-preparation methods may affect whether individual differences in their properties exist. Further studies are required using a low-density cell-expansion technique to establish a new regenerative treatment using subacromial bursa-derived MSCs for irreparable rotator cuff tears.

Editorial Commentary: Are We Ready to Apply Stem Cell Therapy in Rotator Cuff Tear Surgery?

For rotator cuff tear surgery, application of mesenchymal stem cells (MSCs) is a promising new option. Among various MSC sources, synovial tissue contains a high number of MSCs with high chondrogenic potential. Because chondrogenic formation is an important factor in enthesis healing in rotator cuff repair, synovial MSCs derived from the subacromial bursa are superior candidates for the augmentation of rotator cuff tear surgery.

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.

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.

Patients aged in their 70s do not have a high risk of progressive osteoarthritis following arthroscopic femoroacetabular impingement correction and labral preservation surgery.

PURPOSE: The purposes of this study were to (1) evaluate the effect of age on clinical outcomes of arthroscopic femoroacetabular impingement (FAI) with labral preservation surgery and (2) identify predictors of poor postoperative clinical outcomes. METHODS: Eighty-four patients who underwent hip arthroscopic treatment for FAI between 2009 and 2013 were retrospectively reviewed. Patients were divided into three groups based on age. The Advanced age group consisted of patients over 70 years old, the Middle age group consisted of patients in their 50s and 60s, and the Younger age group consisted of patients less than 50 years of age. Total hip arthroplasty (THA) conversion, radiographic progression of osteoarthritis and patient-reported outcomes including modified Harris Hip Score (MHHS) and Non-arthritic Hip Score (NAHS) were investigated. RESULTS: The mean follow-up period was 32.2 (range 24-60) months. THA was required in 3 patients in their 50s and 60s, which was a significantly higher rate compared to that in patients Younger than 50 years old (17% vs 0%, p = 0.036). Progression to osteoarthritis was also significantly more frequent in patients in their 50s and 60s than in patients in their 70s (50s and 60s: 33%; 70s: 0%, p = 0.030). In all age groups, the preoperative MHHS and NAHS improved at last follow-up (p < 0.001). The 50s and 60s age group [hazard ratio (HR) 6.62], preoperative mild osteoarthritic change (Tönnis grade 1, HR: 3.29) and severe cartilage damage on the acetabulum (HR: 2.63) were risk factors for progressive osteoarthritis and THA conversion. CONCLUSIONS: Arthroscopic FAI correction and labral preservation surgery provide favourable clinical outcomes for patients over 70 years old in the absence of significant osteoarthritis and severe acetabular chondral damage. Patients in their 50s and 60s have a higher risk of both THA conversion and progressive osteoarthritis, while patients aged over 70 years show no evidence of progressive osteoarthritis. Chronologic age in isolation is not an absolute contra-indication to hip arthroscopy. LEVEL OF EVIDENCE: III.

Skeletal unloading reduces cluster of differentiation (CD) 38 expression in the bone marrow and osteoblasts of mice.

BACKGROUND: Mechanical unloading induces bone loss in human weight-loaded bones. The findings of recent studies have revealed that cluster of differentiation 38 knockout mice display bone loss similar to that observed in osteoporosis. This study aimed to determine whether the expression of cluster of differentiation 38 is implicated in skeletal unloading and reloading. METHODS: Eight-week-old male C57BL/6J mice were assigned to control, tail-suspension, or reloading after tail-suspension groups. In the tail-suspension group, tail suspension elevated the hind limbs for 1 week. The bilateral femurs and tibias from the groups were evaluated for cluster of differentiation 38 immunocytochemistry, and the cluster of differentiation 38 messenger ribonucleic acid levels and the expression of cluster of differentiation 38 and other cell-surface antigens were evaluated using quantitative real-time polymerase chain reaction and flow cytometric analyses. RESULTS: In the tail-suspension group, the alkaline phosphatase reactivity, cluster of differentiation 38 immunoreactivity in the bone marrow and osteoblasts, and the expression of cluster of differentiation 38 messenger ribonucleic acid and that of other cell-surface antigens were significantly lower than those in the control group. In the reloading after tail-suspension group, the level of cluster of differentiation 38 expression was restored to the same level as that in the control group. CONCLUSIONS: Cluster of differentiation 38 expression declined after skeletal unloading and recovered to normal levels after reloading. In the bone marrow, cluster of differentiation 38 expression plays a crucial role in bone formation in response to mechanical stress.

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).

Predicting Severe Cartilage Damage in the Hip: A Model Using Patient-Specific Data From 2,396 Hip Arthroscopies.

PURPOSE: To determine patient-specific factors that can be used to predict the presence of severe articular cartilage damage in the hip in patients without osteoarthritis. METHODS: The prevalence of severe (Outerbridge grade III or IV) cartilage damage to the acetabulum and femoral head was prospectively recorded at hip arthroscopy. Patients who underwent primary hip arthroscopic surgery between 2006 and 2016 performed by a single surgeon were included. Patients were excluded if they underwent previous hip surgery, had poor-quality radiographs, were younger than 16 years at the time of surgery, or had a minimal joint space of 2 mm or less. The relation between severe cartilage damage and preoperative patient characteristics was examined using multivariable logistic regression analysis with restricted cubic splines. RESULTS: Of the 2,396 hips presenting for hip arthroscopy, 995 (41%) had severe cartilage damage to the acetabulum and 257 (11%) had severe cartilage damage to the femoral head. Older age was a significant risk factor for severe cartilage damage both to the acetabulum (χ2 = 69.5, P < .001) and to the femoral head (χ2 = 53.9, P < .001). An age of 45 years was associated with a 1.96 (95% confidence interval, 1.54-2.49) increase in the odds of severe acetabular cartilage damage and a 3.94 (95% confidence interval, 2.61-5.94) increase in the odds of severe femoral head cartilage damage relative to an age of 20 years. Male sex was associated with severe cartilage damage to the acetabulum (χ2 = 66.7, P < .001), and a lower center-edge angle was a significant risk factor for severe cartilage damage to the femoral head (χ2 = 78.5, P < .001). Predictive nomograms were established for severe cartilage lesions. CONCLUSIONS: The primary risk factors for severe hip cartilage damage were older age for both the femoral head and acetabulum; a lower center-edge angle and larger Tönnis angle for the femoral head; and male sex, body mass index, alpha angle, and joint space for the acetabulum. The likelihood of cartilage damage to the hip can be estimated clinically using a prediction nomogram. LEVEL OF EVIDENCE: Level III, cross-sectional study.

A Prospective, Randomized, Controlled Trial Comparing Conservative Treatment With Trunk Stabilization Exercise to Standard Hip Muscle Exercise for Treating Femoroacetabular Impingement: A Pilot Study.

OBJECTIVE: To assess the efficacy of conservative management of women with femoroacetabular impingement (FAI) using trunk stabilization. DESIGN: Randomized controlled trial (level of evidence: I). SUBJECTS: Twenty FAI female patients who met the inclusion FAI criteria. METHODS: A prospective, randomized, controlled study was performed on 20 female patients with symptomatic FAI comprising 2 groups (10 hips in trunk stabilization exercise group vs 10 hips in control group). We evaluated hip range of motion, isometric muscle strength using a handheld dynamometer (µ-TasMF-01; Anima, Co), and patient-reported outcome measures, including modified Harris hip score, Vail hip score, and international hip outcome tool 12 (iHOT12) before and at 4 weeks and 8 weeks after the intervention. RESULTS: There was a significant improvement in the range of motion of hip flexion in the trunk training group detected as early as 4 weeks after the intervention compared with the control group (P < 0.05). Hip abductor strength significantly improved in the trunk training group at 4 weeks after the intervention, whereas it did not improve in the control group (P < 0.05). Vail hip score and iHOT12 were significantly increased at 8 weeks after the intervention in the trunk training group compared with the control group (iHOT12: 78.7 ± 22.4 vs 53.0 ± 22.3; P < 0.01, Vail hip score: 81.6 ± 18.5 vs 61.1 ± 11.6; P < 0.05). There was no significant difference in the modified Harris hip score between both the groups at 4 and 8 weeks after the intervention. CONCLUSIONS: The addition of trunk stabilization exercise to a typical hip rehabilitation protocol improves short-term clinical outcomes and may augment nonoperative and postoperative rehabilitation.

Higher risk of cam regrowth in adolescents undergoing arthroscopic femoroacetabular impingement correction: a retrospective comparison of 33 adolescent and 74 adults.

Background and purpose - The current literature does not clarify the predictors of cam regrowth and poor clinical outcome following hip arthroscopic femoroacetabular impingement (FAI) correction surgery. Therefore, we investigated the prevalence and risk factors of cam regrowth following arthroscopic FAI correction surgery in skeletally immature patients compared with skeletally mature patients.Patients and methods - 33 teenagers (36 hips as 4 underwent bilateral hip arthroscopies, average age 16.7 [SD 1.6] years, 21 boys [22 hips], 12 girls [14 hips]) undergoing arthroscopic FAI correction and 74 adult controls (74 hips, average age 41 [SD 12] years, 42 men [42 hips], 32 women [32 hips]) were retrospectively reviewed. Postoperative radiographs were obtained, and cam regrowth was evaluated. Clinical characteristics, radiographic findings, arthroscopic findings, and procedures between skeletally immature (SI) and mature (SM) patients were compared. Average follow-up period was 28 months in the SI group and 24 months in the SM group.Results - Preoperatively, 27 of 36 hips were SI, having either a Risser sign grade ≤ 4 of iliac apophysis or open physes of the proximal femur. Cam regrowth was present in 4 of 27 SI hips. The number of cam regrowth cases was significantly higher in SI patients than in SM patients (0/74 hips). 6 patients required revision hip arthroscopic surgeries (4 men: FAI recurrence due to cam regrowth; 2 women: capsulolabral adhesions). At the last follow-up, the mean modified Harris hip score and nonarthritic hip score were significantly improved postoperatively.Interpretation - 4 of 27 SI hips (95% CI 0.04-0.3) had bone regrowth after cam resection arthroscopically. Our case series showed a non-negligible risk of cam regrowth in SI patients, especially in male patients and patients aged approximately 15 years.

Revision Hip Arthroscopy After Labral Reconstruction Using Iliotibial Band Autograft: Surgical Findings and Comparison of Outcomes With Labral Reconstructions Not Requiring Revision.

PURPOSE: To determine the causes of revision hip arthroscopy in patients who underwent labral reconstruction and to compare outcomes of these patients with patients who did not require a revision following reconstruction. METHODS: Patients who underwent revision hip arthroscopy after previous labral reconstruction from 2006 to 2014 were included. Patients with less than 2-year follow-up, preoperative joint space of ≤2 mm, or who underwent other reconstructive procedures at the time of labral reconstruction were excluded. Each patient was matched by year of surgery, age, gender, and the number of previous surgeries with 2 patients that underwent labral reconstruction but did not require a revision following the reconstruction. Preoperatively and at a minimum 2-year follow-up, outcome scores were collected including the Hip Outcome Score-Activities of Daily Living (HOS-ADL) and HOS-Sports Scale, modified Harris Hip Score, Western Ontario and McMaster Universities Index (WOMAC), the 12-Item Short Form Health Survey (SF-12) Physical Component Summary, and the patient satisfaction outcome were collected. Differences between the preoperative and the postoperative outcomes score of each patient in the 2 groups was assessed using the paired t test. The Mann-Whitney U test was used to compare the 2 groups. RESULTS: From 347 patients who underwent iliotibial band autograft labrum reconstruction from 2006 to 2014, 28 hips (8%) in 26 patients (18 females and 8 males) had revision arthroscopy after labral reconstruction. The mean age was 32 years (range: 16-64). The mean number of hip surgeries prior to the labral reconstruction was 1.9 ± 1.2. The average time from the last labral reconstruction procedure to revision labral reconstruction was 27 months (range: 5-59). Procedures performed at revision included lysis of adhesions (100%), additional femoroacetabular impingement (FAI) correction (50%), ligamentum teres debridement (50%), psoas release (29%), labral augmentation or reconstruction (14%), and others. Following revision surgery after previous labral reconstruction, 4 patients (14%) underwent total hip arthroplasty and 2 (7%) patients required a subsequent revision arthroscopy (age 67 and 23) at 15 months and 16 months. The average follow-up time was 3.6 years ± 1 year after revision following labral reconstruction and after labral reconstruction in the nonrevision group. No significant difference was detected in the outcome scores and postoperative satisfaction between the 2 groups. The HOS-ADL improved 16 points in the nonrevision group and 19 points in the revision group. CONCLUSIONS: Patients who underwent revision surgery after labral reconstruction were mostly female, with 2 or more surgeries prior to reconstruction, and 14% required THA and 7% had recurrent scarring. In those who did not fail, outcomes significantly improved and were similar with patients who did not need revision. Adhesions and residual FAI were the most common findings during revision labral reconstruction. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Prevalence of High-Grade Cartilage Defects in Patients With Borderline Dysplasia With Femoroacetabular Impingement: A Comparative Cohort Study.

PURPOSE: To compare the prevalence, size, and location of Outerbridge grade III and IV cartilage defects on the femoral head and acetabulum between patients with borderline acetabular dysplasia and patients with non-borderline dysplasia who underwent hip arthroscopy for femoroacetabular impingement (FAI). METHODS: Patients aged 18 years or older who underwent primary hip arthroscopy for correction of FAI and labral repair from November 2005 to April 2016 were included. We excluded patients with previous hip surgery, a radiographic hip joint space of 2 mm or less, and/or a lateral center-edge angle (LCEA) of less than 20° or greater than 40°. The study patients were divided into 2 groups based on the LCEA on the anteroposterior pelvic radiograph: Patients with an LCEA between 20° and 25° were included in the borderline group, and patients with an LCEA between 25° and 40° were included in the non-borderline group. The prevalence, size, and location of Outerbridge grade III and IV chondral lesions on the femoral head and acetabulum were recorded intraoperatively. Comparisons between groups were performed with the Mann-Whitney U test for nonparametric testing and the t test for data that were normally distributed. Data were analyzed to calculate odds ratios associated with the various factors. RESULTS: In total, 2,429 patients (1,114 women and 1,315 men) met the inclusion criteria. The borderline group consisted of 305 patients (150 men and 155 women), whereas the non-borderline dysplasia group comprised 2,124 patients (1,165 men and 959 women). Outerbridge grade III and IV chondral lesions were found on the femoral head in 118 patients with borderline dysplasia (39%) and 127 patients with non-borderline dysplasia (6%) and on the acetabulum in 132 patients with borderline dysplasia (43%) and 874 patients with non-borderline dysplasia (41%). Patients with borderline dysplasia were 10 times more likely (95% confidence interval, 7.3-13.4; P < .001) to have a grade III or IV cartilage defect on the weight-bearing surface of the femoral head (P < .001) than patients with non-borderline dysplasia. On the acetabular side, no difference in the prevalence of severe cartilage damage was detected between the 2 groups (P = .588). The size of chondral damage was significantly greater in patients with borderline dysplasia on the acetabulum (P = .039) compared with the non-borderline dysplasia group. CONCLUSIONS: Patients with FAI and borderline dysplasia are at higher risk of having Outerbridge grade III and IV chondral damage on the femoral head than patients with non-borderline dysplastic hips. Borderline dysplastic hips also presented with significantly larger chondral defects on the acetabular surface. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Twenty-Year Systematic Review of the Hip Pathology, Risk Factors, Treatment, and Clinical Outcomes in Artistic Athletes-Dancers, Figure Skaters, and Gymnasts.

OBJECTIVE: To identify (1) the predominant level of evidence of the clinical studies regarding the hip pathology, risk factors, treatment, and clinical outcomes in artistic athletes (dancers, figure skaters, and gymnasts) (2) the most commonly reported hip pathology, risk factors, treatments, and clinical outcomes in dancers, figure skaters, and gymnasts. METHODS: To conduct this systematic review PubMed, EMBASE, and Scopus databases were searched for relevant studies and pertinent data were collected from the eligible articles. Included were studies which reported hip injuries in artistic athletes, the risk factors, treatment, and/or the clinical outcomes. We excluded case reports or irrelevant studies. No meta-analysis was performed because of study heterogeneity. The methodical index for nonrandomized studies (MINORS) criteria were used for quality control. MAIN RESULTS: Thirty-eight studies were included in the analysis. The mean MINORS score was 13.6 ± 4.6 points indicating fair quality of evidence of the included articles. The predominant level of evidence was level IV. Chondrolabral pathology and muscle injuries were the most commonly reported pathologies. We found only 2 risk factor analysis studies; however, many studies reported risk correlation between artistic sports or imaging findings and hip pathology. Treatment strategies were reported in only 7 studies, clinical outcomes are significantly underreported. CONCLUSION: Chondrolabral pathology was the most commonly reported hip pathology in artistic athletes, however, prospective cohort studies are necessary to really understand these injuries and their associated risk factors. The lack of clinical outcomes is significant and future data collection is required to assess the effectiveness of the various treatments.