Concomitant Ipsilateral Knee Pain Is Associated With Worse Preoperative Functional Status and Short-Term Outcomes After Hip Arthroscopy in Patients With Femoroacetabular Impingement Syndrome

Abstract

Purpose(1) To determine the effect of concomitant IKP (ipsilateral knee pain) on short-term outcomes after hip arthroscopic treatment of FAIS (femoroacetabular impingement syndrome), and (2) to determine whether IKP would improve with surgery. MethodsData between September 2021 and May 2022 was reviewed. Patients diagnosed with FAIS and underwent hip arthroscopy with minimum of 1-year follow-up were included. Exclusion criteria were prior ipsilateral hip or knee surgery, hip Tönnis grade > 1, knee Kellgren-Lawrence grade > 2, hip conditions (avascular necrosis, Legg-Calve-Perthes disease, pigmented villonodular synovitis, osteoid osteoma, synovial chondromatosis and developmental dysplasia of the hip), and spine diseases. A knee MRI was performed on all patients preoperatively. Preoperative and short-term (1 year) patient-reported outcome (PRO) scores were collected for Hip Sports Activity Scale (HSAS), weekly sports participation, modified Harris Hip Score (mHHS), international Hip Outcome Tool, 12-component form (iHOT-12), visual analog pain scale (VAS) of the hip and ipsilateral knee. The percentage of achieving minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) of mHHS and iHOT-12 were calculated. Multivariate regression analysis was performed to determine the effect of IKP severity on postoperative outcomes. Subgroup analysis was performed between patients with and without IKP alleviation. ResultsAmong the 107 patients included, 47 presented preoperative IKP. Compared to patients without IKP, the IKP cohort had comparable knee structural abnormalities (all with P > 0.05). Still, it showed inferior preoperative mHHS (P = .003), iHOT-12 (P = .016), hip VAS (P = .001), and weekly sports participation (P = .039). Postoperatively, the IKP cohort had lower mHHS (P = .046), iHOT-12 (P = .037), and hip VAS (P = .003), and were less likely to achieve PASS of mHHS (P = .021) and iHOT-12 (P = .049). Patients with higher knee VAS were less likely to achieve PASS of mHHS (OR = 0.61; P = .023). Within the IKP group, knee VAS improved from 2.3 to 1.0 (P < .001). Those with alleviated IKP showed superior postoperative iHOT-12 (P = .038) compared to those with persistent IKP. ConclusionConcomitant IKP at baseline negatively affected preoperative status and short-term PROs after arthroscopic treatment of FAIS. Patients with IKP were less likely to meet clinical thresholds. Most patients achieved IKP alleviation postoperatively, which was associated with superior clinical outcomes. Level of evidenceIII, retrospective cohort study.