Revision hip arthroscopy for hip synovial chondromatosis is effective despite inferior postoperative clinical outcomes compared to patients undergoing primary hip arthroscopy: a matched control study with minimum 2-year follow-up.

purpose(1) To determine the clinical outcomes following revision arthroscopy for patients with hip synovial chondromatosis (SC), and (2) to compare the clinical outcomes between patients undergoing revision hip arthroscopy and primary hip arthroscopy.

methodsPatients undergoing hip arthroscopy between December 2014 and January 2021 was reviewed. Patients treated for SC and confirmed by postoperative pathology were included. Exclusion criteria were age less than 18 years old, hip osteoarthritis (Tönnis grade > 1), history of autoimmune disease, avascular necrosis, and Legg-Calve-Perthes disease. Patients undergoing revision surgery were included in the revision group, while those undergoing primary surgery were matched in a 1:4 ratio and included in the primary group. Preoperative and postoperative patient-reported outcome (PRO) scores including Visual Analog pain Scale (VAS), modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), and international Hip Outcome Tool, 12-component form (iHOT-12) were collected and compared. The PROs and percentage of achieving minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) of mHHS, iHOT-12, and NAHS were compared between the two groups.

resultsA total of 12 patients were included in the revision group, while 48 patients were included in the primary group. No significant difference was found in baseline characteristics (all with P > .05). No significant difference was found in the arthroscopic findings and procedures (all with P > .05). Both groups presented significant improvement of postoperative PROs compared to the preoperative PROs (all with P < .001). No significant difference was found in preoperative PROs between the two groups (all with P > .05). Postoperatively, the revision group presented inferior VAS (P = .007), mHHS (P = .007), iHOT-12 (P = .004), and NAHS (P = .028), as well as lower rate of achieving MCID of NAHS (P = .038), and PASS of mHHS (P = .003) compared to the primary group.

conclusionPatients undergoing revision arthroscopy for hip SC presented favorable clinical outcomes at minimum of 2-year follow-up, although the postoperative PROs, rate of achieving MCID, and PASS were lower compared to patients undergoing primary arthroscopy. LEVEL OF EVIDENCE: III.