Etiology and Complications of Early Aseptic Revision Total Hip Arthroplasty Within 90 Days

BackgroundThe etiology, complications, and rerevision risks of early aseptic revision total hip arthroplasty (THA) within 90 days are insufficiently documented.MethodsA national insurance claims database (PearlDiver Technologies, Fort Wayne, IN) was queried for patients who underwent unilateral aseptic revision THA within 90 days of the index procedure using administrative codes. Patients who underwent revision for infection, without minimum 2-year follow-up, and younger than 18 years were excluded. This cohort was matched based on gender, age, and Charlson Comorbidity Index to a control group of patients who underwent primary THA without revision within 90 days. Two-year rerevision and 90-day complication rates were recorded. Chi-square and Fisher exact tests were used as appropriate for statistical comparison.ResultsFour hundred two patients met the inclusion criteria for early aseptic revision within 90 days of the index procedure and were matched to the control group. The overall 2-year rerevision rate was higher in the early revision group compared with control group (14.9% vs 2.5%, P < .001). Complications within 90 days occurred more frequently in the early revision group, including blood transfusion (10.2% vs 3.2%, P < .001), deep vein thrombosis (9.0% vs 3.2%, P = .001), and pulmonary embolism (2.74% vs 0.75%, P = .031). The most common reasons for early aseptic revision were dislocation (41.5%), fracture (38.1%), and loosening (17.4%).ConclusionEarly aseptic revision THA is associated with significantly higher 90-day complication rates and 2-year rerevision rates compared with a control group of primary THA without revision. The most common reasons for acute early revision were dislocation, fracture, and mechanical loosening.Level of EvidenceLevel III.     

Bicortical Contact Predicts Subsidence of Modular Tapered Stems in Revision Total Hip Arthroplasty

BackgroundWe describe the intraoperative parameters that affect stem subsidence rates in tapered modular femoral stems for revision total hip arthroplasty (THA). We also determine the effect of the stem bicortical contact on subsidence rates and whether there is a minimum threshold bicortical contact that must be achieved to avoid the complication of subsidence.MethodsThis is a retrospective cohort study consisting of 109 hips in 105 patients (53 males and 52 females) at a minimum of 2 years of follow-up. All revisions were carried out for Paprosky type 3A and 3B femoral deficits. Clinical outcomes included the indication for revision, aseptic re-revision surgery, specifications of the stem inserted, and specifications of the femoral head and acetabular components implanted. Radiographic outcome measures included subsidence (mm) and bicortical contact (mm).ResultsUsing multivariate regression analysis, 3 parameters were associated with an increased rate of stem subsidence. A reduced bicortical contact distance (P < .001) and a stem length of ≤155 mm (P < .001) were both associated with higher subsidence rates. We also demonstrated a novel threshold of 20-mm bicortical contact which must be achieved to significantly reduce subsidence rates in these modular femoral stems for revision THA.ConclusionSubsidence rates of modular tapered femoral stems for revision THA can be significantly reduced by increasing the initial bicortical contact of the stem within the diaphysis and the overall length of the femoral stem >155 mm. We describe a minimum threshold bicortical contact distance of 20 mm that should ideally be exceeded to significantly reduce the risk of stem subsidence within the femoral canal.     

Outcomes of Total Knee Arthroplasty Revisions in Obese and Morbidly Obese Patient Populations

BackgroundThe obese population is at higher risk for complications following primary total knee arthroplasty (TKA), but little data is available regarding revision outcomes. This study aimed to investigate the role of body mass index (BMI) in the cause for revision TKA and whether BMI classification is predictive of outcomes.MethodsA multi-institutional database was generated, including revision TKAs from 2012 to 2019. Data collection included demographics, comorbidities, surgery types (primary revision, repeat revision), reasons for revision, lengths of hospital stay, and surgical times. Patients were compared using 3 BMI categories: nonobese (18.5 to 29.9), obese (30 to 39.9), and morbidly obese (≥40). Categorical and continuous variables were analyzed using chi-square and 1-way analysis of variance tests, respectively. Regression analyses were used to compare reasons for revision among weight classes.ResultsObese and morbidly obese patients showed significant risk for repeat revision surgery in comparison to normal weight patients. Obese patients were at higher risk for primary revision due to stiffness/fibrosis and repeat revision due to malposition. In comparison to the obese population, morbidly obese patients were more likely to require primary revision for dislocation and implant loosening.ConclusionSignificant differences in primary and repeat revision etiologies exist among weight classes. Furthermore, obese and morbidly obese patients have a greater risk of requiring repeat revision surgery. These patients should be informed of their risk for multiple operations, and surgeons should be aware of the differences in revision etiologies when anticipating complications following primary TKA.