Preoperative gait speed emerged as the sole independent predictor of excellent outcomes following total hip arthroplasty for hip osteoarthritis, with a threshold of 1.0 m/s distinguishing patients likely to achieve superior functional results at midterm follow-up, according to a retrospective cohort study published in The Journal of Bone & Joint Surgery.
The research, conducted at Kyushu University in Japan, included 274 Asian patients who underwent primary total hip arthroplasty (THA) for osteoarthritis between 2012 and 2018. Investigators employed both Patient Acceptable Symptom State (PASS) criteria and K-means clustering analysis to evaluate outcomes using the Oxford Hip Score (OHS) and the Forgotten Joint Score-12 (FJS-12).
Multivariable regression analysis revealed preoperative 10-m free gait speed significantly predicted both OHS and FJS-12 outcomes. Additional factors influencing the OHS included body mass index and follow-up period, while hip flexion strength also affected FJS-12 scores.
Receiver operating characteristic curve analysis identified distinct gait speed cutoff values for achieving PASS criteria: 0.7 m/s for the OHS and 1.0 m/s for the FJS-12.
Using K-means clustering, researchers classified 230 patients who completed both outcome measures into three distinct groups based on normalized three-dimensional distribution of OHS pain subscores, OHS function subscores, and FJS-12 scores. The excellent outcome group (Cluster 1, 98 patients) demonstrated favorable results across all three measures.
Patients in the excellent outcome group were significantly younger (mean age, 64.0 vs 66.6 years), exhibited greater hip abduction strength (0.55 vs 0.44 Nm/kg), and demonstrated faster preoperative gait speed (0.98 vs 0.85 m/s) compared with the control group. Notably, symptom duration (5.4 vs 6.5 years) and pain intensity measured by visual analog scale (38.4 vs 43.6 mm) showed no statistically significant differences between groups.
In the secondary analysis, preoperative 10-m free gait speed was the only significant predictor of classification into the excellent outcome group, with an odds ratio of 5.85, regardless of patient age. The receiver operating characteristic curve analysis yielded a gait speed cutoff value of 1.0 m/s for excellent outcomes.
Factors influencing preoperative gait speed included age at surgery, hip flexion range of motion, hip flexion strength, and pain intensity.
The mean follow-up period was 7 years (range, 1.2 to 11.4 years). Mean values for the OHS and FJS-12 were 44 and 54, respectively. The study population was predominantly female (89%), with a mean age of 66 years and mean body mass index of 24 kg/m².
The identified 1.0 m/s threshold aligns with established sarcopenia criteria. A meta-analysis reported typical gait speed at 60 to 69 years of age ranges from 1.2 to 1.4 m/s, further supporting the clinical relevance of the 1.0 m/s benchmark.
Study limitations included its retrospective design, potential inaccuracies in determining symptom onset from medical records, the predominance of female patients reflecting Asian hip osteoarthritis epidemiology, and the inclusion of patients with arthritis in other joints, which may have influenced gait speed measurements. Patients who routinely used canes were permitted to use them during gait speed assessment.
Full disclosures can be found in the published study.