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. Pre- and intraoperative findings can predict the poor clinical outcomes after hip arthroscopic surgery for FAI in the setting of BDDH. Case control study; Level of evidence, 3. 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. 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). 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.

Background: Patients with developmental dysplasia of the hip (DDH) have a greater risk of acetabular labral tearing and joint instability, which predispose them to developing osteoarthritis. The arthroscopic management of DDH, however, remains controversial. Hypothesis: Specific clinical characteristics and radiographic parameters correlate with and predict a worsened clinical outcome after hip arthroscopic surgery for DDH. Study Design: Case control study; Level of evidence, 3. Methods: Of patients with DDH who underwent an arthroscopic procedure between March 2009 and June 2011, there were 28 hips in 28 patients (6 male and 22 female) that met the inclusion criteria. The mean patient age was 28.4 years. 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 modified Harris Hip Score (mHHS) that remained 85. Univariate analysis and Cox hazard proportional analysis were performed on the 2 subpopulations. Results: There were 9 patients in the failure group (including 3 hips with T nnis grade 2) and 19 patients in the success group. In 22 of 28 patients, the mean mHHS significantly improved from 61.6 ± 18.8 (range, 12.0-85.0) preoperatively to 94.3 ± 7.0 (range, 73.7-100.0) at final follow-up, and the mean Non-Arthritic Hip Score (NAHS) improved from 56.2 ± 13.9 (range, 35.0-81.3) preoperatively to 92.7 ± 9.5 (range, 65.0-100.0) at final follow-up ( P < .001, Wilcoxon signed-rank test). Univariate analysis showed that a broken Shenton line was significantly more prevalent in the failure group compared with the success group (8/9 [89%] vs 3/19 [16%] patients, respectively; P < .001). High-grade cartilage delamination (Multicenter Arthroscopy of the Hip Outcomes Research Network [MAHORN] grades 3-5) was significantly higher in the failure group than in the success group (8/9 [89%] vs 3/19 [16%] patients, respectively; P < .001). The median femoral neck-shaft (FNS) angle in the failure group was significantly higher than that in the success group (139° vs 134°, respectively; P = .01). Further, Cox hazard proportional analysis of the failure group showed that the predictors for a poor clinical outcome were the presence of a broken Shenton line, FNS angle >140°, center-edge (CE) angle 23 kg/m ² , acetabular cartilage damage (MAHORN grades 3-5), and cartilage damage of the femoral head (International Cartilage Repair Society grades 2-4). The most important predictors for a poor clinical outcome at the time of surgery were a broken Shenton line and an FNS angle >140°. Conclusion: Patients with a broken Shenton line, FNS angle >140°, CE angle 23 kg/m ² at the time of surgery are not good candidates for the arthroscopic management of DDH.

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. Adolescent throwing athletes would return to preinjury levels of function after arthroscopic osteochondral fragment fixation using HA/PLLA thread pins. Case series; Level of evidence, 4. 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. 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. Arthroscopic fragment fixation using HA/PLLA thread pins provides a beneficial clinical outcome to adolescent baseball players with humeral capitellar OCD.

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.

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.

Background: Femoroacetabular impingement (FAI) has been reported as a cause of hip pain in young patients and is suggested as the trigger for hip osteoarthritis (OA). The goal of this study was to quantify the metabolic profiles of articular tissues (cartilage, synovium, and labrum) harvested from patients with FAI and with end-stage OA. In addition, we sought to investigate the development of secondary OA in hips with FAI. Methods: Tissue samples were obtained from thirty hips undergoing arthroscopic surgery for FAI with or without labral tear and thirty hips undergoing total hip arthroplasty for OA. Quantitative real-time polymerase chain reaction (PCR) was performed to determine the gene expression of inflammatory cytokines and metabolic (anabolic and catabolic) enzymes. The differences in gene expression in articular tissues from the patients with FAI were also evaluated on the basis of clinical parameters (age range and alpha angle). Results: The messenger RNA (mRNA) expression of the inflammatory cytokines interleukin-1 beta (IL-1β) and IL-8 and of matrix metalloproteinase (MMP)-3 (a catabolic gene) in both the synovium and the labrum, and the expression of collagen type I alpha 1 (an anabolic gene) in the labrum, was higher in the samples from hips with OA than in those from hips with FAI (p < 0.05). In cartilage, however, the mRNA expression of the inflammatory cytokines and the catabolic genes MMP-13 and ADAMTS-4 (a disintegrin and metalloproteinase with thrombospondin motifs-4) was higher in the FAI samples compared with the OA samples (p < 0.01). When the expression of inflammatory cytokines was evaluated among the three types of tissues within each disease group, the expression levels were the highest in cartilage within the FAI samples (p < 0.01). In FAI cartilage, we found higher gene expression of aggrecan (ACAN) and ADAMTS-4 in the samples from patients with larger alpha angles (≥60°) (p < 0.01). Conclusions: Our results indicate that the metabolic conditions of articular cartilage in FAI and OA are different and that the expression of genes associated with inflammation is greater in the articular cartilage of patients with FAI compared with the synovium and the labrum. The metabolic changes were heightened by mechanical impingement. Clinical Relevance: The articular cartilage from the impingement lesion in patients with FAI showed biologically higher inflammation and degeneration, supporting the concept that FAI may be a trigger for joint degeneration.