Influence of Tönnis Grade on Outcomes of Arthroscopic Management of Symptomatic Femoroacetabular Impingement

Abstract

PURPOSE: To define the outcomes of arthroscopic correction of femoroacetabular impingement (FAI) based on Tönnis findings within a previously reported patient population, including a comparative analysis of Tönnis grade 0 and 1 versus grade 2 changes. METHODS: Outcomes (modified Harris Hip Score [mHHS]) of a previously published study of arthroscopic correction of FAI were correlated with Tönnis grade. The inclusion criteria were the first 100 consecutive patients undergoing arthroscopic FAI correction with minimum 2-year follow-up. These procedures were performed between December 2003 and May 2006. Grades were determined independently by 2 experienced clinicians. Tönnis grades 0 and 1 were compared with Tönnis grade 2. Independent variables of sex and age were also evaluated. RESULTS: The average age of the entire group was 34.7 years (range, 13-76 years), with 66 male and 34 female patients. Of the patients, 17 had Tönnis grade 0, 49 had Tönnis grade 1, 29 had Tönnis grade 2, and 4 had Tönnis grade 3 (1 unknown). The average mHHS improvement for Tönnis grade 0 was 20.6 points; Tönnis grade 1, 22.2 points; Tönnis grade 2, 14.9 points; and Tönnis grade 3, 18.8 points. The improvement was statistically (P < .01) and clinically (>8 points) significant across all Tönnis grades. There was no difference (P = .077) between Tönnis grades 0 and 1 (21.8 points) versus grade 2 (14.9 points). There was no difference based on sex or age. CONCLUSIONS: These data support that statistically and clinically meaningful successful patient-reported outcomes (mHHS) at 2 years can be encountered even in the presence of Tönnis grade 2 radiographic features. Neither age nor sex was an indicator of poorer results within similar Tönnis grades. LEVEL OF EVIDENCE: Level III, case-control study.