Endoscopic Shelf Acetabuloplasty Combined With Hip Arthroscopic Labral Repair, Cam Osteoplasty, and Capsular Plication Enables Elite Athletes With Acetabular Dysplasia to Return to Sport: A Case Series.

OBJECTIVE: To investigate clinical outcomes and return to sport timeline for athletes with acetabular dysplasia after endoscopic shelf acetabuloplasty (ESA). DESIGN: A retrospective review. SETTING: Wakamatsu Hospital of the University of Occupational and Environmental Health, Japan between 2012 and 2019. PATIENTS: Fifteen elite athletes (median age: 20 years) of 253 patients undergoing ESA, arthroscopic labral repair/reconstruction, cam osteochondroplasty, and capsular plication. The mean follow-up period was 27.8 months after surgery. MAIN OUTCOME MEASURES: Patient-reported outcome scales (PROSs), including the modified Harris Hip Score, Nonarthritic Hip Score, International Hip Outcome Tool 12, Hip Outcome Score-Sports, and Vail Hip Score. RESULTS: After ESA, all 15 elite athletes were able to return to sport effectively and compete at a preoperative level. The mean time between the operation and the first practice was 6.5 months, while the mean time between the ESA procedure and the first game was 9.6 months. Approximately 27.8 months after surgery, PROS outcomes improved significantly with no hips requiring emergency revision surgery at the final follow-up. At a mean of 47.1 months after surgery, 7 athletes decided to retire from their sport. Up to 71.1 months after surgery, the additional 8 patients continued to compete in their sport at an elite level. CONCLUSIONS: ESA enables elite athletes with acetabular dysplasia to return to competition at a mean of 9.6 months postsurgery. The ESA procedure is an effective and promising method of treating elite athletes with acetabular dysplasia. LEVEL OF EVIDENCE: IV.

Association of combined hip-pelvic-lumbar mobility with hip muscle strength and clinical outcomes in patients treated for femoroacetabular impingement syndrome: A case-control study.

BACKGROUND: It is unclear whether hip and pelvic mobility in the sagittal plane are associated with hip function in FAIS. This study aimed to determine whether hip-pelvis-lumbar mobility is associated with preoperative hip function and postoperative outcomes in FAIS. METHODS: This was a level 3 case-control study. This study included 111 patients who underwent arthroscopic FAI correction and labral preservation between 2015 and 2019. The Hip-Pelvic-Lumbar Mobility Test (HPLMT) was performed preoperatively; hip flexion with the hip adducted and internally rotated was examined in the lateral decubitus position, and a total hip flexion angle of less than 120° was diagnosed as positive. HPLMT-positive patients were classified as cases, and HPLMT-negative patients were classified as controls. Hip muscle strength was measured preoperatively using a hand-held dynamometer. The modified Harris hip score (mHHS), Nonarthritic Hip Score (NAHS), and International Hip Outcome Tool-12 score were obtained preoperatively and postoperatively. The rates of patient acceptable symptomatic state (PASS) achievement for patient-reported outcome scores (PROSs) were compared between groups. RESULTS: The preoperative PROSs for the HPLMT-positive patients were significantly lower than those for the HPLMT-negative patients. HPLMT-positive patients had significantly weaker hip strength on the affected side than HPLMT-negative patients (flexion; p < 0.001, abduction; p = 0.001). HPLMT-positive patients had significantly lower postoperative mHHS than HPLMT-negative patients. HPLMT-positive patients were significantly less likely to achieve a PASS for the mHHS (62% versus 85%) and NAHS (48% versus 71%) than HPLMT-negative patients. CONCLUSION: Hip-pelvis-lumbar mobility is associated with hip function and clinical outcomes in FAIS patients. The HPLMT is an efficient tool for assessing FAIS patients.

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.

Development of a novel knee contracture mouse model by immobilization using external fixation.

AIMS: Several studies have used animal models to examine knee joint contracture; however, few reports detail the construction process of a knee joint contracture model in a mouse. The use of mouse models is beneficial, as genetically modified mice can be used to investigate the pathogenesis of joint contracture. Compared to others, mouse models are associated with a lower cost to evaluate therapeutic effects. Here, we describe a novel knee contracture mouse model by immobilization using external fixation. METHODS: The knee joints of mice were immobilized by external fixation using a splint and tape. The passive extension range of motion (ROM), histological and immunohistochemical changes, and expression levels of fibrosis-related genes at 2 and 4 weeks were compared between the immobilized (Im group) and non-immobilized (Non-Im group) groups. RESULTS: The extension ROM at 4 weeks was significantly lower in the Im group than in the Non-Im group (p < 0.01). At 2 and 4 weeks, the thickness and area of the joint capsule were significantly greater in the Im group than in the Non-Im group (p < 0.01 in all cases). At 2 weeks, the mRNA expression levels of the fibrosis-related genes, except for the transforming growth factor-ß1, and the protein levels of cellular communication network factor 2 and vimentin in the joint capsule were significantly higher in the Im group (p < 0.01 in all cases). CONCLUSION: This mouse model may serve as a useful tool to investigate the etiology of joint contracture and establish new treatment methods.

Accurate cup placement using a portable navigation system during total hip arthroplasty based on pelvic orientation in the lateral decubitus position.

BACKGROUND: We previously proposed an accurate cup placement procedure using a portable navigation system (PNS) for total hip arthroplasty (THA) in the lateral decubitus position; however, the accuracy of our proposed procedure has not been shown, the aim of this study was to demonstrate the accuracy. METHODS: We prospectively analyzed 79 hips treated with primary THA; 40 hips treated until June 2020 were included in the conventional procedure (CP) group, and 39 hips treated from July 2020 were included in the modified procedure (MP) group. In the MP, pelvic orientation is considered to be the set coordinate axes in addition to the CP using the PNS. The accuracy was based on the difference between the navigation record (NR) and postoperative computed tomography measurement. RESULTS: The radiographic inclination (RI) and anteversion (RA) accuracies were 1.55° and 2.14°, respectively, in the MP group and 3.03° and 6.20°, respectively, in the CP group (p < 0.001). The error was within 5° of the NR for both the RI and RA in 34 in the MP group (87.2%) and 14 in the CP group (35.0%) (p < 0.001). The error was within 5° of the target angle (RI 40°, RA 15°) for both the RI and RA in 29 hips in the MP group (74.7%) and 12 in the CP group (30.0%) (p < 0.001). CONCLUSIONS: Our procedure with the consideration of pelvic orientation achieved dramatically improved the accuracy of PNS and was suitable to facilitate accurate cup placement.

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.

The posteromedial corner of the knee: an international expert consensus statement on diagnosis, classification, treatment, and rehabilitation.

PURPOSE: To establish recommendations for diagnosis, classification, treatment, and rehabilitation of posteromedial corner (PMC) knee injuries using a modified Delphi technique. METHODS: A list of statements concerning the diagnosis, classification, treatment and rehabilitation of PMC injuries was created by a working group of four individuals. Using a modified Delphi technique, a group of 35 surgeons with expertise in PMC injuries was surveyed, on three occasions, to establish consensus on the inclusion or exclusion of each statement. Experts were encouraged to propose further suggestions or modifications following each round. Pre-defined criteria were used to refine item lists after each survey. The final document included statements reaching consensus in round three. RESULTS: Thirty-five experts had a 100% response rate for all three rounds. A total of 53 items achieved over 75% consensus. The overall rate of consensus was 82.8%. Statements pertaining to PMC reconstruction and those regarding the treatment of combined cruciate and PMC injuries reached 100% consensus. Consensus was reached for 85.7% of the statements on anatomy of the PMC, 90% for those relating to diagnosis, 70% relating to classification, 64.3% relating to the treatment of isolated PMC injuries, and 83.3% relating to rehabilitation after PMC reconstruction. CONCLUSION: A modified Delphi technique was applied to generate an expert consensus statement concerning the diagnosis, classification, treatment, and rehabilitation practices for PMC injuries of the knee with high levels of expert agreement. Though the majority of statements pertaining to anatomy, diagnosis, and rehabilitation reached consensus, there remains inconsistency as to the optimal approach to treating isolated PMC injuries. Additionally, there is a need for improved PMC injury classification. LEVEL OF EVIDENCE: Level V.

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.

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.

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.

How Useful Is the Flexion-Adduction-Internal Rotation Test for Diagnosing Femoroacetabular Impingement: A Systematic Review.

OBJECTIVE: Clinicians use the flexion, adduction, and internal rotation (FADIR) test in the diagnosis of femoroacetabular impingement (FAI). However, the diagnostic utility of this test remains unclear. The purpose of this review was to determine the utility of the FADIR test in diagnosing FAI. DATA SOURCES: MEDLINE, EMBASE, and PubMed were searched using relevant key terms and study screening was performed in duplicate. Patient demographics, diagnostic imaging, and summary measures (eg sensitivity, specificity, etc.) of the FADIR test in patients with FAI were recorded. MAIN RESULTS: Eight studies of levels III (87.5%) and IV (12.5%) evidence were included. Four hundred fifty-two patients (622 hips) with a mean age of 27.0 ± 9.0 were examined. Alpha (75.1%) and/or center-edge (26.8%) angles were used to diagnose hips with FAI. X-ray (78.9%), magnetic resonance imaging (MRI) (16.2%), and computed tomography (CT) (4.8%) were used to confirm the diagnosis of FAI. The sensitivity when confirmed by x-ray, MRI, or CT was 0.08 to 1, 0.33 to 1 and 0.90, respectively. The specificity when confirmed by x-ray and MRI was 0.11 and 1, respectively. CONCLUSIONS: Although the overall utility of the FADIR test in diagnosing FAI remains unclear given its moderate sensitivity and specificity, it may be a useful screening tool for FAI because of its low risk. Clinicians should consider the variability in sensitivity and specificity values reported and the low quality of literature available. Future studies should use large sample sizes and consistent radiographic measurements to better understand the usefulness of this physical examination maneuver in diagnosing FAI. LEVEL OF EVIDENCE: Level IV, Systematic Review of Level III and IV studies.

Arthroscopic anterior inferior iliac spine decompression does not alter postoperative muscle strength.

PURPOSE: The purpose of this study was to assess the additional effect of anterior inferior iliac spine (AIIS) decompression on knee extensor and hip flexor strength and compare functional outcomes after arthroscopic FAI correction with and without AIIS decompression. METHODS: Sixty patients who underwent arthroscopic FAI correction surgery were divided into two groups matched for AIIS morphology: 31 patients who underwent arthroscopic FAI surgery only (without AIIS decompression) (FAI group) (AIIS Type I; n = 5, Type II; n = 26, Type III; n = 0) and 29 patients who underwent arthroscopic FAI surgery with AIIS decompression (AIIS group) (AIIS Type I; n = 5, Type II; n = 24, Type III; n = 0). Knee extensor and hip flexor strength were evaluated preoperatively and at 6 months after surgery. Patient-reported outcome (PRO) scores using the modified Harris hip score (MHHS), the nonarthritic hip score (NAHS) and iHOT-12 were obtained preoperatively and at 6 months after surgery. RESULTS: In the AIIS group, there was no significant difference between knee extensor strength pre- and postoperatively (n.s.). In the AIIS group, hip flexor strength was significantly improved postoperatively compared to preoperative measures (p < 0.05). In the FAI group, there were no significant improvements regarding muscle strength (n.s.). While there were no significant differences of preoperative and postoperative MHHS and NAHS between both groups (MHHS; n.s., NAHS; n.s.), the mean postoperative iHOT-12 in the FAI group was inferior to that in the AIIS group. (p < 0.01). The revision surgery rate for the AIIS group was significantly lower compared with that in the FAI group (p < 0.05). CONCLUSION: Anterior inferior iliac spine decompression, as a part of an arthroscopic FAI corrective procedure, had a lower revision surgery rate and did not compromise knee extensor and hip flexor strength, and it improved clinical outcomes comparable to FAI correction without AIIS decompression. AIIS decompression for FAI correction improved postoperative PRO scores without altering the muscle strength of hip flexor and knee extensor. LEVEL OF EVIDENCE: III.

Correction to: Clinical and radiographic predictors of failed hip arthroscopy in the management of dysplasia: a systematic review and proposal for classification.

Unfortunately, the author name was incorrectly published in the original publication as Sochi Uchida insted of Soshi Uchida. The author name is corrected here by this Erratum. The â€‹original â€‹article â€‹has â€‹been â€‹corrected.

Clinical and radiographic predictors of failed hip arthroscopy in the management of dysplasia: a systematic review and proposal for classification.

PURPOSE: As indications for hip arthroscopy continue to expand, its efficacy in patients with more complex deformities of the hip, such as those with acetabular dysplasia, remains controversial. The purpose of this systematic review is to identify the predictors of failed hip arthroscopy in dysplastic hips and to propose a standardize prognostic sub-classification of dysplasia. METHODS: This systematic review was performed in accordance with the (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) PRISMA guidelines. Three databases [EMBASE, PubMed, and Ovid (MEDLINE)] were searched using terms including "hip arthroscopy" and "dysplasia". Studies were screened and data extracted in duplicate. Study quality was assessed using the Methodological Index for Non-Randomized Studies criteria. Due to the non-uniform nature of study data, findings were presented in descriptive summary form. RESULTS: Thirteen studies were included in this systematic review, comprising 712 dysplastic patients (773 hips) with mean age 34.2 years and 74.1% females. Most studies defined hip dysplasia by a lateral centre-edge angle (LCEA) of 20°-25° (borderline) or 15°-20° (moderate). Failure was defined as progression to revision arthroscopy, peri-acetabular osteotomy, or total hip arthroplasty. Overall, failure rate was 192/743 (25.8%) at an average of 28.1 months following index arthroscopy. Smaller LCEA, larger Tönnis angle, broken Shenton line, and decreased joint space (≤ 2 mm) were radiographic predictors of failure. Severe cartilage lesions to the femoral head or acetabulum were associated with failure in five studies. Labral debridement led to more failures than labral repair. CONCLUSION: Overall, hip arthroscopy yielded good outcomes in mildly dysplastic hips without severe chondral damage. Hip arthroscopy is expected to result in a failed outcome in individuals with moderate-to-severe hip dysplasia (LCEA < 15°), severe cartilage lesions, larger Tönnis angle (> 20°), broken Shenton line, and decreased joint space (≤ 2 mm). Arthroscopic surgery may be more effective in individuals with borderline-to-mild (LCEA 15°-25°) acetabular dysplasia in the absence of severe cartilaginous lesions (7-year survival: 89.6%). A standardized prognostic classification of hip dysplasia based on the LCEA and Tönnis angle is proposed. LEVEL OF EVIDENCE: Systematic review of non-randomized studies, Level 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.

Deep gluteal syndrome is defined as a non-discogenic sciatic nerve disorder with entrapment in the deep gluteal space: a systematic review.

PURPOSE: Clinicians are not confident in diagnosing deep gluteal syndrome (DGS) because of the ambiguity of the DGS disease definition and DGS diagnostic pathway. The purpose of this systematic review was to identify the DGS disease definition, and also to define a general DGS diagnostic pathway. METHODS: A systematic search was performed using four electronic databases: PubMed, MEDLINE, EMBASE, and Google Scholar. In eligibility criteria, studies in which cases were explicitly diagnosed with DGS were included, whereas review articles and commentary papers were excluded. Data are presented descriptively. RESULTS: The initial literature search yielded 359 articles, of which 14 studies met the eligibility criteria, pooling 853 patients with clinically diagnosed with DGS. In this review, it was discovered that the DGS disease definition was composed of three parts: (1) non-discogenic, (2) sciatic nerve disorder, and (3) nerve entrapment in the deep gluteal space. In the diagnosis of DGS, we found five diagnostic procedures: (1) history taking, (2) physical examination, (3) imaging tests, (4) response-to-injection, and (5) nerve-specific tests (electromyography). History taking (e.g. posterior hip pain, radicular pain, and difficulty sitting for 30 min), physical examination (e.g. tenderness in deep gluteal space, pertinent positive results with seated piriformis test, and positive Pace sign), and imaging tests (e.g. pelvic radiographs, spine and pelvic magnetic resonance imaging (MRI)) were generally performed in cases clinically diagnosed with DGS. CONCLUSION: Existing literature suggests the DGS disease definition as being a non-discogenic sciatic nerve disorder with entrapment in the deep gluteal space. Also, the general diagnostic pathway for DGS was composed of history taking (posterior hip pain, radicular pain, and difficulty sitting for 30 min), physical examination (tenderness in deep gluteal space, positive seated piriformis test, and positive Pace sign), and imaging tests (pelvic radiographs, pelvic MRI, and spine MRI). This review helps clinicians diagnose DGS with more confidence. LEVEL OF EVIDENCE: IV.

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.

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.

Posterolateral corner of the knee: an expert consensus statement on diagnosis, classification, treatment, and rehabilitation.

PURPOSE: To develop a statement on the diagnosis, classification, treatment, and rehabilitation concepts of posterolateral corner (PLC) injuries of the knee using a modified Delphi technique. METHODS: A working group of three individuals generated a list of statements relating to the diagnosis, classification, treatment, and rehabilitation of PLC injuries to form the basis of an initial survey for rating by an international group of experts. The PLC expert group (composed of 27 experts throughout the world) was surveyed on three occasions to establish consensus on the inclusion/exclusion of each item. In addition to rating agreement, experts were invited to propose further items for inclusion or to suggest modifications of existing items at each round. Pre-defined criteria were used to refine item lists after each survey. Statements reaching consensus in round three were included within the final consensus document. RESULTS: Twenty-seven experts (100% response rate) completed three rounds of surveys. After three rounds, 29 items achieved consensus with over 75% agreement and less than 5% disagreement. Consensus was reached in 92% of the statements relating to diagnosis of PLC injuries, 100% relating to classification, 70% relating to treatment and in 88% of items relating to rehabilitation statements, with an overall consensus of 81%. CONCLUSIONS: This study has established a consensus statement relating to the diagnosis, classification, treatment, and rehabilitation of PLC injuries. Further research is needed to develop updated classification systems, and better understand the role of non-invasive and minimally invasive approaches along with standardized rehabilitation protocols. LEVEL OF EVIDENCE: Consensus of expert opinion, Level V.

Exploring the validation of a Japanese version of the International Hip Outcome Tool 12: Reliability, validity, and responsiveness.

BACKGROUNDS: The International Hip Outcome Tool 12 (iHOT12) was authorized by the Multicenter Arthroscopy of the Hip Outcomes Research Network (MAHORN). iHOT12 is increasingly being adopted in orthopedic studies to report patient outcomes. This study aimed to develop a Japanese version of the International Hip Outcome Tools "iHOT12J", and to establish its reliability, validity, and responsiveness. METHODS: To assess test-retest reliability, an identical set of patients reported outcome measures with five qualitative scoring measures including iHOT12; these were filled out by each patient twice. Reliability was explored using Cronbachss alpha and intraclass correlation coefficient. The Bland-Altman plot was used to explore the absolute agreement. To evaluate validity, we examined the relationships between SF36 and iHOT12. Responsiveness was assessed by comparing the smallest detectable change to the minimal important change by applying an anchor-based approach. RESULTS: Fifty patients (51 joints) were analyzed from March 2016 to October 2017 in Japanese four facility. The Cronbach α coefficient was 0.90 and the average value of intraclass coefficient (ICC) was 0.89. Bland-Altman plot analysis showed a solid agreement. Regarding the validity, the Spearman rank correlation coefficients were strong with PF (r = 0.69, p < 0.01), BP (r = 0.71, p < 0.01) and PCS (r = 0.69, p < 0.01). The smallest detectable change (3.19) was smaller than the minimum important change (12.40). CONCLUSIONS: We developed iHOT12J, which seems to show sufficient reliability, validity, and responsiveness. We believe that this patient reported outcome measure is beneficial in studying Japanese patients with femoroacetabular impingement.