Summary: Case-control study appears to show that mesenchymal stem cells (MSCs) offer better and sustained results compared to microfracture (control group) for patients with chondral defects undergoing hip arthroscopy. ISHA Annual Scientific Meeting 2016 S29
Introduction: Chondral defects in hip joint pose a treatment challenge during hip arthroscopy. Authors and others have described the use Mesenchymal stem cells (MSCs) in treatment of chondral defects. Aim of the study was to establish medium-term results of MSCs in treatment of International Cartilage Repair Society (ICRS) grade 2-4 osteochondral defects in patients undergoing hip arthroscopy compared to a matched group undergoing microfracture treatment while controlling for confounding factors.
Methods: A prospective case-control study was designed including a total of 80 patients undergoing hip arthroscopy for femoroacetabular impingement (FAI) with chondral defect (grade 2-4). Patients with dysplasia, previous surgery and grade 4 defects larger than 3cm2 were excluded. Of these, 40 consecutive patients had hip arthroscopy for FAI and treatment of the chondral defect using bone marrow harvested MSCs with biodegradable scaffold (MSC group). The control arm included matched group of consecutive patients that only received microfracture for the osteochondral defect (control group). All patients underwent excision of impingement lesion, labral stabilisation and additional procedures carried out as appropriate. The collected data included demographic details, osteochondral defect grading, radiographic and MRI parameters, surgical intervention, modified Harris Hip Score (mHHS), visual analogue score (VAS) for patient satisfaction (0-10, 10 ¼ very satisfied), Non-Arthritic Hip Score (NAHS), radiographic assessment and any adverse effects including revision hip arthroscopy and conversion to arthroplasty. Data were collected pre and per-operatively and 6, 12, 26 and 52 weeks post-operatively and yearly thereafter. Mean follow-up was 28 months (24, 36 months). Descriptive statistics were used and comparative tests included t-test for parametric variables and chi-squared test for nonparametric variables with significance value set at 5% and power of study at 80%.
Results: The mean age in the MSC group and control group was 41.3 (22 to 69) and 40.5(19, 64) respectively. There were ICRS grade 4 defects in 45% and 41% of patients in MSC and control group. Demographics in the two groups were matched. Pre-operative mean scores improved in the MSC group (mHHS from 63.4 to 87.2 (p < 0.001), VAS from 5.2(median 6) to 9 (median 9), NAHS from 61 to 82 (p ¼ 0.003) and in control group (mHHS from 66.2 to 82, VAS from median 5.5(median 6) to 8.4(median 8), NAHS from 62 to 76(p ¼ 0.001). The improvement remained sustained in majority of MSC group (97.5%) at mean follow-up of 28-months while late deterioration occurred in 17.5% of control group. In MSC and control groups the revision hip arthroscopy rate was 2.5% and 10%, and conversion to hip replacement rate 2.5% and 7.5% respectively.
Conclusion: Treatment of chondral defects with MSCs appears to offer safe and effective treatment and results are better sustained than the microfracture control group. Conversion to hip arthroplasty risk appears to decrease with MSC treatment in medium-term.