AJSM - 2026-05-24 - Journal Article
Arthroscopy for Femoroacetabular Impingement in Tonnis Grade 2 Arthritic Hips Results in Similar Clinical and Radiographic Outcomes but Lower Survivorship Than Tonnis Grades 0 and 1: A Systematic Review and Meta-analysis.
Krivicich L, Driscoll A, Hayes-Lattin M, Guenthner G, Yen YM, Salzler M
Topics
Key Takeaway
Tönnis grade 2 hips undergoing arthroscopy for FAI achieve similar mHHS improvement to Tönnis 0 and 1 hips but carry a significantly higher rate of conversion to THA (OR 5.27 vs Tönnis 0, though Tönnis 2 vs 3 did not reach significance at OR 5.27, 95% CI 0.91–30.51).
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Summary
This systematic review and meta-analysis examined whether preoperative Tönnis grade predicts clinical, radiographic, or survivorship outcomes after hip arthroscopy for FAIS across 29 studies. Tönnis 2 hips demonstrated similar mHHS improvement compared to Tönnis 0 (SMD -0.22, P=.27) and Tönnis 1 (SMD -0.24, P=.06), and similar revision arthroscopy rates across all grades (OR 1.65, P=.31). However, increasing Tönnis grade correlated with significantly higher THA conversion rates, with Tönnis 2 hips at substantially elevated risk compared to lower grades.
Key Limitation
Level IV aggregate evidence with significant between-study heterogeneity in key PRO comparisons limits the precision of pooled estimates and precludes causal inference about arthroscopy efficacy in Tönnis 2 hips.
Original Abstract
BACKGROUND
An expanding body of literature is available on arthroscopy for femoroacetabular impingement syndrome (FAIS). Studies have attempted to relate Tonnis grade to postoperative outcomes but do not often provide a complete picture of the clinical, radiographic, and failure outcomes for a given Tonnis cohort.
PURPOSE
To systematically review and meta-analyze the impact of preoperative arthritic changes, as measured by Tonnis grade, on clinical, radiographic, and survivorship outcomes in patients undergoing hip arthroscopy for FAIS.
STUDY DESIGN
Systematic review; Level of evidence, 4.
METHODS
PubMed, EMBASE, and Web of Science Core Collection databases were queried for investigations associating preoperative Tonnis grade with postoperative outcomes after hip arthroscopy for FAIS. Eligible articles compared patient-reported outcomes (PROs), radiographic arthritis progression, or rate of secondary surgical interventions between patients with various Tonnis arthritis grades. Continuous random-effects models were used to compare PROs between arthritic grades as represented by standardized mean difference (SMD), whereas restricted maximum likelihood random-effects models compared event rates of Tonnis grade progression and secondary surgical interventions, reported as odds ratio (OR).
RESULTS
A total 29 investigations were included in this systematic review, of which 16 studies provided sufficient quantitative data for meta-analysis. The 3972 hips included were followed for a mean of 68.4 months (range, 24.0-150.0 months); the mean age was 39.6 years (range, 20.3-63.3 years). Meta-analysis revealed similar results between Tonnis 0 and 1 cohorts for modified Harris Hip Score (SMD = 0.05, 95% CI [-0.33, 0.42]; I 2 = 73.35%; P = .80), Hip Outcome Score (HOS)-Activities of Daily Living (SMD = -0.16, 95% CI [-0.36, 0.04]; I 2 = 0.00%; P = .12), HOS-Sports Subscale (SMD = -0.36, 95% CI [-0.97, 0.25]; I 2 = 89.14%; P = .25), and Tonnis progression (OR = 2.66, 95% CI [0.51-13.95]; I 2 = 58.80%; P = .25). The Tonnis 2 cohort was found to have similar mHHS to Tonnis 0 (SMD = -0.22, 95% CI [-0.60, 0.17]; I 2 = 52.52%; P = .27) and Tonnis 1 (SMD = -0.24, 95% CI [-0.48, 0.01]; I 2 = 0.00%; P = .06). Tonnis 0, 1, and 2 cohorts were found to have similar rates of revision arthroscopy (OR = 1.65, 95% CI [0.63-4.28]; I 2 = 0.00%; P = .31). Increasing Tonnis grade was found to have increased rates of conversion to total hip arthroplasty, except for Tonnis 2 and 3 having similar rates of conversion (OR = 5.27, 95% CI [0.91-30.51]; I 2 = 0.00%; P = .06).
CONCLUSION
A systematic review of 29 studies identified relevant data, and meta-analysis of 16 studies that provided sufficient quantitative data revealed that compared with Tonnis grade 0 and 1 hips, Tonnis grade 2 hips had similar symptomatic improvement, reflected by select PROs, but decreased joint survivorship, reflected by significantly higher rates of conversion to total hip arthroplasty.