Biomechanical Analysis of Hip Braces after Hip Arthroscopic Surgery for Femoroacetabular Impingement Syndrome: An Observational Study.

Currently, hip braces are recommended and typically worn by femoroacetabular impingement (FAI) patients after hip arthroscopic surgery. However, there is currently a lack of literature regarding the biomechanical effectiveness of hip braces. The purpose of this study was to investigate the biomechanical effect of hip braces after hip arthroscopic surgery for FAI. Overall, 11 patients who underwent arthroscopic FAI correction and labral preservation surgery were included in the study. Standing-up and walking tasks in unbraced and braced conditions were performed at 3 weeks postoperatively. For the standing-up task, videotaped images of the hip's sagittal plane were recorded while patients stood from a seated position. After each motion, the hip flexion-extension angle was calculated. For the walking task, acceleration of the greater trochanter was measured using a triaxial accelerometer. For the standing-up motion, the mean peak hip flexion angle was found to be significantly lower in the braced condition than in the unbraced condition. Furthermore, the mean peak acceleration of the greater trochanter was significantly lower in the braced condition than in the unbraced condition. Patients undergoing arthroscopic FAI correction surgery would benefit from usage of a hip brace in terms of protecting repaired tissues during early postoperative recovery.

Hip arthroscopic management for treating a rhythmic gymnast with a large bone cyst at the femoral head in the setting of hip dysplasia-a case report.

Recent literature lacks a clear understanding of how to manage bone cysts associated with hip dysplasia. This article aimed to report a case of hip dysplasia in a rhythmic gymnast surgically managed with arthroscopic retrograde bone grafting, labral repair, cam osteoplasty, double shoelace capsular closure and endoscopic shelf acetabuloplasty. A 20-year-old female college rhythmic gymnast presented complaining of right hip pain and discomfort for the past 2 months. This case report describes the use of the CROSSTRAC guide system to perform retrograde bone grafting to treat the bone cyst at the femoral head arthroscopically. Hip arthroscopic retrograde bone grafting, labral repair, cam osteoplasty, double shoelace capsular closure and endoscopic shelf acetabuloplasty are less invasive and beneficial for the treatment of bone cysts of the femoral head associated with hip dysplasia in symptomatic rhythmic gymnasts.

Isolation and Characterization of Synovial Mesenchymal Stem Cells Derived From Patients With Chronic Lateral Ankle Instability: A Comparative Analysis of Synovial Fluid, Adipose Synovium, and Fibrous Synovium of the Ankle Joint.

Background: Synovial mesenchymal stem cells (MSCs) have high proliferative potential and are considered an excellent source for stem cell therapy. Purposes: To isolate MSCs from the synovium of ankle joints in patients with chronic lateral ankle instability (CLAI) and to compare the characteristics of MSCs derived from the synovium anterior to the talus with those from the surrounding anterior talofibular ligament (ATFL) synovium. Study Design: Controlled laboratory study. Methods: The synovium was harvested from 2 locations in the ankle, the synovium anterior to the talus and the surrounding ATFL synovium, of 14 patients who underwent arthroscopic ATFL repair for CLAI without osteochondral lesions of the talus (OLTs). Synovial fluid was also harvested. MSCs were isolated from both types of synovial tissue, as well as synovial fluid. The number of MSCs in the synovium and their viability, proliferation, colony-forming units, and potential to differentiate into adipose, bone, and cartilage tissues were determined and compared between groups. Additionally, real-time polymerase chain reaction was used to assess the differentiation capacity of adipose, bone, and cartilage tissues from both samples. The Wilcoxon signed rank test was used to compare the sample weight, number of colonies, number of nucleated cells per colony, yield obtained, and phenotypic characteristics of MSCs derived from different locations of the synovium. Results: No significant differences were observed in the sample weight (P = .051), number of nucleated cells per milligram (P = .272), number of colonies (P = .722), and yield obtained (P = .099) between the 2 groups. MSCs could not be isolated from synovial fluid. The frequency of oil red O-positive adipogenic colonies (P = .028) and the expression of the adipsin gene (P < .05) were significantly increased in the cells from the synovium anterior to the talus compared to those in the cells from the surrounding ATFL synovium. However, chondrogenic and osteogenic potentials were not significantly different between the 2 groups. Conclusion: Synovial MSCs obtained from the ankle joint had self-renewal and multilineage differentiation potential, although the adipogenesis potential of MSCs from the synovium anterior to the talus was superior to that from the surrounding ATFL synovium. Clinical Relevance: Both the adipose synovium and fibrous synovium in the ankle joints of patients with CLAI may be a good source of MSCs for stem cell therapy applications, whereas synovial fluid appeared unsuitable.

Endoscopic Shelf Acetabuloplasty Concomitant With Labral Repair, Cam Osteoplasty, and Capsular Plication to Treat Acetabular Dysplasia in Artistic Athletes: A Case Series.

BACKGROUND: Knowledge of clinical outcomes and return to artistic activities after endoscopic shelf acetabuloplasty (ESA) for acetabular dysplasia in artistic athletes is lacking. HYPOTHESIS: Hip arthroscopic surgery including ESA will enable artistic athletes to return to their activities with a high success rate, significantly improved acetabular coverage, and preserved joint cartilage. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: We reviewed 28 hips in 23 female artistic athletes (14 ballet, 9 rhythmic gymnastics, 4 dance, and 1 baton twirling) who underwent arthroscopic labral preservation, capsular plication, and ESA. Their mean age was 25.8 ± 10.2 years. Preoperatively, all patients had generalized joint laxity (Beighton score, 7.1 ± 1.8). We evaluated preoperative and postoperative radiographs and outcome scores including the modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), International Hip Outcome Tool 12 (iHOT-12), Vail Hip Score (VHS), and Hip Outcome Score-Sports (HOS- Sports). Statistical analysis was performed using paired t tests and Bonferroni correction. RESULTS: The mean follow-up was 32.5 ± 12.5 months. The mean lateral center-edge angle significantly increased from preoperatively (15.7° ± 5.3°) to postoperatively (39.8° ± 8.2°; P < .001) and at the final follow-up (33.7° ± 8.6°; P < .001). The vertical-center-anterior angle significantly improved from preoperatively (16.2° ± 8.8°) to final follow-up (33.6° ± 8.0°; P < .001). All hips maintained a Tönnis grade of 0 or 1 at the final follow-up. Overall, 20 patients (87%) were able to return to their preinjury level. All outcome scores improved from preoperatively to postoperatively: mHHS, from 68.5 ± 18.1 to 88.3 ± 18.5; NAHS, from 50.8 ± 17.7 to 69.0 ± 11.4; iHOT-12, from 36.9 ± 19.3 to 75.2 ± 19.8; VHS, from 53.8 ± 13.7 to 79.4 ± 19.4; and HOS--Sports, from 59.9 ± 17.0 to 79.6 ± 21.3 (P < .001 for all). In total, 3 patients could not return to artistic activities as the result of postoperative deep gluteal syndrome. CONCLUSION: ESA concomitant with labral repair, cam osteoplasty, and capsular plication to treat dysplastic hips in patients with joint laxity enabled artistic athletes to return to their activities with a high success rate.

The prevalence and risk factors of pubic bone marrow edema in femoroacetabular impingement and hip dysplasia.

Femoroacetabular impingement syndrome (FAIS) has been associated with osteitis pubis; however, it is still unclear whether hip dysplasia is associated with osteitis pubis. This study aimed to investigate (i) the incidence of pubic bone marrow edema (BME) on magnetic resonance imaging in symptomatic patients with FAIS, borderline developmental dysplasia of the hip (BDDH) and developmental dysplasia of the hip (DDH) undergoing hip arthroscopic surgery with labral preservation and (ii) the demographic and radiographic factors associated with pubic BME. A total of 259 symptomatic patients undergoing hip arthroscopic surgery between July 2016 and April 2019 were retrospectively reviewed and divided into three groups: FAIS (180 patients), BDDH (29 patients) and DDH (50 patients). Diffuse changes in the pubic bone adjacent to the pubic symphysis were labeled pubic BME, and the prevalence of their occurrence was examined. Multivariate logistic regression analysis was performed to identify factors involved in pubic BME, and odds ratios (ORs) for relevant factors were calculated. There was no significant difference in the prevalence of pubic BME among the three groups (20 [11.1%] of 180 FAIS patients, 6 [20.6%] of 29 BDDH patients and 7 [14%] of 50 DDH patients, P = 0.325). Multivariate logistic regression analysis showed that acetabular coverage was not associated with pubic BME, whereas younger age and greater alpha angle were still independent associated factors [age ≤26 years (OR, 65.7) and alpha angle ≥73.5° (OR, 4.79)]. Determining the possible association of osteitis pubis with cam impingement in dysplastic hips may provide insights toward a more accurate understanding of its pathophysiology.

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.

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.

Arthroscopic Double Shoelace Capsular Plication Technique for the Treatment of Borderline Hip Dysplasia Associated With Capsular Laxity.

Hip arthroscopy is an innovative surgical tool that is minimally invasive; however, the working space is very limited because of small surgical wounds. Recent literature has shown that capsular repair after capsulotomy during hip arthroscopy facilitates the restoration of hip joint stability. Previous Technical Notes have introduced the shoelace capsule closing technique using a single Ultratape. However, even with the shoelace capsule closing technique, we periodically have encountered difficult cases with extensive capsular laxity. In this Technical Note, we introduce an improved hip capsule plication technique using 2 pieces of Ultratape for treating borderline hip dysplasia with capsular laxity. This double shoelace capsule plication technique theoretically reduces tearing risks during closure of delicate and fragile capsules. Level of evidence: 1 (hip); 2 (other).

Hip Arthroscopic Management Can Improve Osteitis Pubis and Bone Marrow Edema in Competitive Soccer Players With Femoroacetabular Impingement.

BACKGROUND: There is a dearth of knowledge regarding the correlation between femoroacetabular impingement (FAI) and osteitis pubis (OP) among symptomatic soccer players. PURPOSE: To elucidate whether arthroscopic FAI correction is effective for young competitive soccer players with FAI combined with OP or perisymphyseal pubic bone marrow edema (BME). STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A total of 577 consecutive patients who underwent arthroscopic FAI correction were retrospectively reviewed with a minimum 2-year follow-up. Competitive soccer players who were professional, college, and high school athletes were included. The authors assessed the modified Harris Hip Score and Nonarthritic Hip Score preoperatively and at 6 months, 1 year, and 2 years after surgery. In addition, players were divided into groups according to radiographic evidence of OP and BME (2 groups each). Clinical outcomes, return to play, and radiographic assessments were compared between groups. RESULTS: Twenty-eight hips met the inclusion criteria. The median modified Harris Hip Score significantly improved after hip arthroscopy (81.4, preoperatively; 95.7 at 6 months, P = .0065; 100 at 1 year, P = .0098; 100 at 2 years, P = .013). The median Nonarthritic Hip Score also significantly improved (75.0, preoperatively; 96.3 at 6 months, P = .015; 98.8 at 1 year, P = .0029; 100 at 2 years, P = .015). Furthermore, 92.0% of players returned to play soccer at the same or higher level of competition at a median 5.5 months (range, 4-15 months); 67.8% had radiological confirmation of OP; and 35.7% had pubic BME. The alpha angle was significantly higher in pubic BME group than the no-pubic BME group (64.8° vs 59.2°, P = .027), although there was no significant difference between the OP and no-OP groups. The prevalence of tenderness of the pubic symphysis significantly decreased preoperatively (32.1%) to postoperatively (3.6%). Magnetic resonance imaging findings confirmed that pubic BME disappeared in all players at a median 11 months (range, 6-36) after initial surgery. CONCLUSIONS: Arthroscopic management for FAI provides favorable clinical outcomes, a high rate of return to sports, and, when present, resolution of pubic BME among competitive soccer players.

Synovial Mesenchymal Stem Cells Derived From the Cotyloid Fossa Synovium Have Higher Self-renewal and Differentiation Potential Than Those From the Paralabral Synovium in the Hip Joint.

BACKGROUND: Several studies have shown the relationship between poorer clinical outcomes of arthroscopic femoroacetabular impingement syndrome surgery and focal chondral defects or global chondromalacia/osteoarthritis. Although recent studies described good outcomes after the conjunctive application of synovial mesenchymal stem cells (MSCs), none demonstrated the application of synovial MSCs for cartilaginous hip injuries. PURPOSE: To compare the characteristics of MSCs derived from the paralabral synovium and the cotyloid fossa synovium and determine which is the better source. STUDY DESIGN: Controlled laboratory study. METHODS: Synovium was harvested from 2 locations of the hip-paralabral and cotyloid fossa-from 18 donors. The number of cells, colony-forming units, viability, and differentiation capacities of adipose, bone, and cartilage were collected and compared between groups. In addition, real-time polymerase chain reaction was used to assess the differentiation capacity of adipose, bone, and cartilage tissue from both samples. RESULTS: The number of colonies and yield obtained at passage 0 of synovium from the cotyloid fossa was significantly higher than that of the paralabral synovium ( P < .01). In adipogenesis experiments, the frequency of detecting oil red O-positive colonies was significantly higher in the cotyloid fossa than in the paralabral synovium ( P < .05). In osteogenesis experiments, the frequency of von Kossa and alkaline phosphatase positive colonies was higher in the cotyloid fossa synovium than in the paralabral synovium ( P < .05). In chondrogenic experiments, the chondrogenic pellet culture and the gene expressions of COL2a1 and SOX9 were higher in the cotyloid fossa synovium than in the paralabral synovium ( P < .05). CONCLUSION: MSCs from the cotyloid fossa synovium have higher proliferation and differentiation potential than do those from the paralabral synovium and are therefore a better source. CLINICAL RELEVANCE: Synovial cells from the cotyloid fossa synovium of patients with femoroacetabular impingement syndrome are more robust in vitro, suggesting that MSCs from this source may be strongly considered for stem cell therapy.

Endoscopic shelf acetabuloplasty can improve clinical outcomes and achieve return to sports-related activity in active patients with hip dysplasia.

PURPOSE: To investigate clinical outcomes and return to sports-related activity following endoscopic shelf acetabuloplasty combined with labral repair in the treatment of the active patients with developmental dysplasia of the hip (DDH). METHODS: Between 2011 and 2013, 32 patients (36 hips; 11 males and 21 females; 11 right 17 left 4 bilateral; median age 28.5, range 12-51 years), who underwent endoscopic shelf acetabuloplasty combined with labral repair and met the inclusion criteria were enrolled in this study. There was a minimum follow-up of 2 years (average 32.3 ± 3 months, range 24-48 months). Patient-reported outcome (PRO) scores including the modified Harris Hip Score (MHHS) and Non-Arthritis Hip Score (NAHS) were obtained preoperatively and at final follow-up for the assessment of surgical outcomes. RESULTS: The mean MHHS significantly improved from 68.4 ± 14.3 (range 23.1-95.7) preoperatively to 94.5 ± 8.5 (range 66-100) at final follow-up (p = 0.001). Similarly, the NAHS also significantly improved from 51.3 ± 11.9 (range 23-76) preoperatively to 73.0 ± 7.4 (range 44-80) at final follow-up (p = 0.001). The mean LCE angle significantly increased postoperatively but partially decreased at final follow-up (mean preoperative versus postoperative versus final follow-up: 16.0 range 5-24, versus 40.1 range 27-58, versus 30.1 range 20-41. p = 0.001, respectively). There were 3 patients who returned to a higher activity level, 20 patients who returned to the same activity level, and 6 patients who returned to a lower activity level. The mean period from surgery to return to play was 9.0 ± 3.5 months (range 5-18). CONCLUSION: Endoscopic shelf acetabuloplasty provides promising clinical outcomes and return to sports-related activity for active patients with DDH. LEVEL OF EVIDENCE: Level IV.

Predictors of Poor Clinical Outcome After Arthroscopic Labral Preservation, Capsular Plication, and Cam Osteoplasty in the Setting of Borderline Hip Dysplasia.

BACKGROUND: Borderline developmental dysplasia of the hip (BDDH) is frequently diagnosed concurrently with cam impingement. While hip arthroscopy has advanced the treatment of hip joint pathology, including femoroacetabular impingement (FAI), arthroscopic treatment for FAI in the setting of BDDH remains a challenge amid a subset of patients. The risk factors of poor clinical results after hip arthroscopic labral preservation and FAI corrections in the setting of BDDH patients have not been well established. HYPOTHESIS: Pre- and intraoperative findings can predict the poor clinical outcomes after hip arthroscopic surgery for FAI in the setting of BDDH. STUDY DESIGN: Case control study; Level of evidence, 3. METHODS: Of patients with BDDH (defined as lateral center edge [LCE] angle between 20° and 25°) who underwent arthroscopic procedures for FAI between 2009 and 2014, 45 met inclusion criteria (45 hips: 15 males and 30 females). Their mean age was 31.4 years (range, 12-65 years), and the mean LCE angle was 23.2°. Clinical and radiographic follow-up evaluations up to a minimum of 2 years after surgery were performed for all patients. Failure of the procedure was defined as conversion to subsequent surgery or having a Tönnis osteoarthritis grade of 2, and success was defined as patients who did not need subsequent surgery. Univariate analysis and Cox hazard proportional analysis were performed for both cohorts. RESULTS: Of 45 patients, 11 (24%) had revision surgery (endoscopic shelf acetabuloplasty for 5 patients, total hip arthroplasty for 2, and revision hip arthroscopy for 2) or advanced to Tönnis grade ≥2 osteoarthritis and thus constituted the failure group. In the success group, modified Harris Hip Score (median, pre- vs postoperative: 72.1 vs 100, P< .001, Wilcoxon signed-rank test) and nonarthritic hip score (58.8 vs 98.8, P< .001) were significantly improved at the minimum 2-year follow-up. The median age of the failure group was significantly higher than that of the success group (47.0 vs 20.0, P< .001, Mann-Whitney Utest). Risk factors of poor clinical outcomes were identified as follows: age ≥42 years (hazard ratio [HR], 11.6; 95% CI, 2.5-53.9; P= .002, Cox hazard model), broken Shenton line (HR, 6.4; 95% CI, 1.9-22.3; P= .003), Tönnis angle ≥15° (HR, 3.9; 95% CI, 1.2-12.9; P= .03), vertical center anterior (VCA) angle ≤17° (HR, 5.0; 95% CI, 1.5-17.1; P= .01), Tönnis grade 1 at preoperative radiograph (HR, 3.6; 95% CI, 1.1-11.7; P= .04), severe cartilage delamination at acetabulum (HR, 11.8; 95% CI, 3.0-46.1; P< .001), and mild cartilage damage at femoral head (HR, 8.1; 95% CI, 2.1-30.8; P= .002). CONCLUSION: Preoperative predictors of poorer outcomes from hip arthroscopic labral preservation, capsular plication, and cam osteoplasty in the setting of BDDH are age ≥42 years old, broken Shenton line, osteoarthritis, Tönnis angle ≥15°, and VCA angle ≤17° on preoperative radiographs. Intraoperative predictors of poorer outcomes are severe acetabular chondral damage and even mild femoral chondral damage. Although the patients in the setting of BDDH may have good outcomes from isolated hip arthroscopy, caution is suggested for those with the aforementioned risk factors.

A Comparison of Clinical Outcome Between Athletes and Nonathletes Undergoing Hip Arthroscopy for Femoroacetabular Impingement.

OBJECTIVE: To compare the clinical outcome of arthroscopic surgery for femoroacetabular impingement (FAI) between athlete and nonathlete patients. DESIGN: Retrospective case-control study. Level of Evidence III. PATIENTS AND METHODS: Seventy-four patients who underwent arthroscopic FAI correction from March 2009 to April 2012 were enrolled in this study. The patients were divided into 2 groups, according to their sports participation (47 in the athlete group and 27 in the nonathlete group). MAIN OUTCOME MEASURES: We reviewed clinical and radiographic data for all patients, up to a minimum of 2 years after surgery. We used analysis of covariance to compare the mean patient reported outcome scores including modified Harris hip score (MHHS) and the nonarthritis hip score (NAHS) preoperatively, at 6, 12, and 24 months after surgery. RESULTS: The mean age at the time of surgery in the athlete group was significantly lower than that in the nonathlete group. Although there was no significant difference in preoperative MHHS and NAHS, the mean NAHS at 6, 12, and 24 months postoperatively and the mean MHHS at 24 months postoperatively in athletes were significantly higher than that in nonathletes (P < 0.05). CONCLUSIONS: Although arthroscopic FAI correction and labral preservation surgery is generally beneficial, it appears to provide a better clinical outcome in athletes than in nonathletes.

Isolation and Characterization of Synovial Mesenchymal Stem Cell Derived from Hip Joints: A Comparative Analysis with a Matched Control Knee Group.

Purpose. To determine the characteristics of MSCs from hip and compare them to MSCs from knee. Methods. Synovial tissues were obtained from both the knee and the hip joints in 8 patients who underwent both hip and knee arthroscopies on the same day. MSCs were isolated from the knee and hip synovial samples. The capacities of MSCs were compared between both groups. Results. The number of cells per unit weight at passage 0 of synovium from the knee was significantly higher than that from the hip (P < 0.05). While it was possible to observe the growth of colonies in all the knee synovial fluid samples, it was impossible to culture cells from any of the hip samples. In adipogenesis experiments, the frequency of Oil Red-O-positive colonies and the gene expression of adipsin were significantly higher in knee than in hip. In osteogenesis experiments, the expression of COL1A1 and ALPP was significantly less in the knee synovium than in the hip synovium. Conclusions. MSCs obtained from hip joint have self-renewal and multilineage differentiation potentials. However, in matched donors, adipogenesis and osteogenesis potentials of MSCs from the knees are superior to those from the hips. Knee synovium may be a better source of MSC for potential use in hip diseases.

Elcatonin prevents bone loss caused by skeletal unloading by inhibiting preosteoclast fusion through the unloading-induced high expression of calcitonin receptors in bone marrow cells.

This study aimed to clarify whether elcatonin (EL) has a preventive action on bone dynamics in skeletal unloading. Seven-week-old male C57BL/6J mice with either ground control (GC) or tail suspension (TS) were administered EL 20U/kg or a vehicle (veh) three times per week and assigned to one of the following four groups: GCEL, GCveh, TSEL, and TSveh. Blood samples and bilateral femurs and tibias of the mice were obtained for analysis. After 7days of unloading, the trabecular bone mineral density in the distal femur obtained via peripheral quantitative computed tomography and the trabecular bone volume were significantly higher in the TSEL group than in the TSveh group. The bone resorption histomorphometric parameters, such as the osteoclast surface and osteoclast number, were significantly suppressed in the TSEL mice, whereas the number of preosteoclasts was significantly increased. The plasma level of tartrate-resistant acid phosphatase-5b (TRACP-5b) was significantly lower in the TSEL group than in all other groups. In the bone marrow cell culture, the number of TRACP-positive (TRACP(+)) multinucleated cells was significantly lower in the TSEL mice than in the TSveh mice, whereas the number of TRACP(+) mononucleated cells was higher in the TSEL mice. On day 4, the expression of nuclear factor of activated T-cells, cytoplasmic, calcineurin-dependent 1 (NFATc1), cathepsin K and d2 isoform of vacuolar ATPase V0 domain (ATP6V0D2) mRNA in the bone marrow cells in the TSEL mice was suppressed, and the expression of calcitonin receptor (Calcr) mRNA on day 1 and Calcr antigen on day 4 were significantly higher in the TSveh mice than in the GCveh mice. EL prevented the unloading-induced bone loss associated with the high expression of Calcr in the bone marrow cells of mouse hindlimbs after tail suspension, and it suppressed osteoclast development from preosteoclasts to mature osteoclasts through bone-resorbing activity. This study of EL-treated unloaded mice provides the first in vivo evidence of a physiological role of EL in the inhibition of the differentiation process from preosteoclasts to osteoclasts.

Arthroscopic fragment fixation using hydroxyapatite/poly-L-lactate Acid thread pins for treating elbow osteochondritis dissecans.

BACKGROUND: Various procedures, such as arthroscopic debridement, osteochondral transplantation, and bone plug fixation, have been described for the treatment of osteochondritis dissecans (OCD) of the humeral capitellum. However, the use of hydroxyapatite/poly-L-lactate acid (HA/PLLA) thread pins to fix the osteochondral fragment in an OCD lesion is a recent development. HYPOTHESIS: Adolescent throwing athletes would return to preinjury levels of function after arthroscopic osteochondral fragment fixation using HA/PLLA thread pins. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Enrolled in this prospective cohort study were 18 adolescent baseball players (mean age, 14.2 years; range 12-16, years) with elbow OCD who underwent arthroscopic fragment fixation with HA/PLLA thread pins between 2006 and 2009. All patients were affected on their dominant side. Plain radiographs taken before surgery showed an open physis in 13 patients (72%) and a closed physis in 5 patients (28%). During surgery, the condition of the OCD lesion was evaluated by use of the International Cartilage Research Society (ICRS) classification system; there were 5 grade II, 11 grade III, and 2 grade IV cases. Outcomes were assessed after 3 years (mean, 39 months; range, 36-50 months). Elbow function was measured using the Timmerman and Andrews score and the Mayo Elbow Performance Index. Return to sports activity was assessed as higher than preinjury, same level, lower level, or no return to sports. RESULTS: The mean Timmerman and Andrews score improved significantly from 126.6±6.5 to 197.5±1.5, and the mean Mayo Elbow Performance Index improved significantly from 68.0±2.1 to 98.06±0.9 (P=.0001 for both). Mean elbow extension improved significantly from -10°±10.4° to -0.8°±5.2° (P=.006), and mean flexion improved significantly from 123.1°±17.9° to 138.6°±6.1° (P=.001). Three patients had a loss of extension greater than 5°. Five patients returned to a higher level of sports activity, 10 patients returned to the same level, and 2 patients returned to a lower level. A remaining patient did not return to baseball. In one patient, the lesion did not heal, resulting in fragmentation at 1 year after surgery. This patient consequently underwent revision arthroscopy to remove the lesion, and he eventually returned to sports at the same level of activity. CONCLUSION: Arthroscopic fragment fixation using HA/PLLA thread pins provides a beneficial clinical outcome to adolescent baseball players with humeral capitellar OCD.