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.

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]; I2 = 73.35%; P = .80), Hip Outcome Score (HOS)-Activities of Daily Living (SMD = -0.16, 95% CI [-0.36, 0.04]; I2 = 0.00%; P = .12), HOS-Sports Subscale (SMD = -0.36, 95% CI [-0.97, 0.25]; I2 = 89.14%; P = .25), and Tonnis progression (OR = 2.66, 95% CI [0.51-13.95]; I2 = 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]; I2 = 52.52%; P = .27) and Tonnis 1 (SMD = -0.24, 95% CI [-0.48, 0.01]; I2 = 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]; I2 = 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]; I2 = 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.