Septic arthritis of the native hip joint: a multi-pattern, multi-outcome disease

Septic arthritis of the native hip joint (SANH) is an uncommon surgical and medical emergency with few reports. The aim of this study was to determine predictors of return to theatre (RTT), complications and mortality.

Patients with SANH were identified from January 2009 to June 2022; 50 patients and three subgroups were identified: Pyogenic (surgical washout without systemic inflammatory disease), Systemic (surgical washout with SIDs) and patients managed non-surgically. Patterns of these groups were assessed with a principal component analysis. The cumulative incidences for death, any complication and RTT for repeat washout were calculated. The predictive variables associated with outcomes were selected with univariable models and then incorporated in multivariable CoxPH regressions.

The 1-year cumulative incidence was 14% for mortality and 48.5% for any complication. Amongst patients managed surgically, 1-year risk of RTT was 46% in Pyogenic subgroup and 21% in Systemic subgroup. Systemic subgroup had lower complications and RTT and higher rate of sterile aspirate, compared to Pyogenic. Charlson comorbidity index (CCI) (HR = 1.41, P value = 0.03), preoperative albumin (HR = 0.81, P value = 0.009) and preoperative haemoglobin (HR = 0.95, P value = 0.02) were significantly associated with 1-year mortality. Time between symptom onset and admission > 7 days (HR = 3.15, P value = 0.042), preoperative Hb (HR = 1.05, P value = 0.016), socioeconomic deprivation (HR = 1.18, P value = 0.04) and Systemic subgroup (HR = 0.25, P value = 0.04) were significantly associated with RTT.

Mortality was well predicted by the usual parameters including CCI, albumin, but also low haemoglobin. Patients presenting in a delayed fashion were more likely to have multiple lavages.