Arthroscopic Microfracture of the Hip: Prospective Clinical Outcomes with Minimum Two-Year Follow-up
Objectives: Articular cartilage damage is challenging for orthopaedists to address because of its limited healing capacity. Outcome studies dedicated to a cohort of patients receiving microfracture in the hip have focused on second look arthroscopy and return to sport, which have shown favorable results in the absence of osteoarthritis (OA). There are few previous studies focusing on clinical outcomes after microfracture in the hip using patient reported outcome (PRO) tools. The purpose of the study is to evaluate the clinical outcomes of a series of patients treated with microfracture using PRO tools, with a minimum of 2-year follow-up.
Methods: During the study period between August 2008 and January 2011, all patients treated with microfracture during arthroscopic surgery of the hip for full thickness articular cartilage defects were included in the study. Exclusion criteria were previous hip conditions, such as Legg-Calves-Perthes disease, avascular necrosis (AVN), Tonnis grade > 2 and workers compensation status. Patient-reported outcome (PRO) scores used include the modified Harris Hip Score (mHHS), the Non-Arthritic Hip Score (NAHS), the Hip Outcome Score - Activities of Daily Living (HOS-ADL), and the Hip Outcome Score - Sport Specific Subscale (HOS-SSS). PRO scores were collected pre-operatively and at 3 months, 12 months, and 24 months postoperatively. Visual analog scale (VAS) pain scores and patient satisfaction rating were also collected. Any revision surgeries, complications, additional surgery or conversions to THA were noted.
Results: A total of 27 cases met the inclusion/exclusion criteria, of which 22 patients (81%) were available for follow-up at minimum 2 years postoperatively. Nineteen patients (86%) were classified as survivors, not requiring conversion to THA. Three patients (14%) went on to have total hip arthroplasty (THA). One patient (4%) required revision arthroscopy and went on to have notable improvement. The score improvement from preoperative to 2-year follow-up was 60.5 to 80.8 for mHHS, 56.9 to 77.5 for NAHS, 65.8 to 78.8 for HOS-ADL, and 37.9 to 70.7 for HOS-SSS. All improvements were statistically significant (p<0.05). VAS scores significantly decreased from 5.7 to 3.6 (p<0.001), and satisfaction averaged 7.6 on a 1 - 10 scale.
Conclusions: At minimum 2-year follow-up, there were statistically significant improvements in all PROs for patients undergoing microfracture during arthroscopic hip surgery. A high survivorship was noted, and those patients who were not survivors had diffuse degenerative changes. We conclude that in the absence of diffuse degeneration, results of microfracture for focal chondral defects of the hip are favorable.