A systematic review and meta-analysis of hybrid vs. cemented stems - which method is more optimal for revision total knee arthroplasty?

INTRODUCTION: The number of primary and revision Total Knee Arthroplasty (TKA) cases are expected to increase in future. There are various advantages and disadvantage to employing either of the two main types of stem fixation methods - cemented or hybrid technique. This review aimed to study the most optimal fixation method for revision TKAs by comparing radiological outcomes and re-revision rates. METHODS: A systematic review and meta-analysis was performed using PubMed and Cochrane Library from 2010 to identify studies explicitly comparing outcomes between cemented against hybrid fixation revision TKA techniques, with a minimum follow up of at least 24 months. A total of 8 studies was included in this review. Egger's test and visual inspection of the funnel plot did not reveal publication bias. RESULTS: There was no statistically significant difference in radiological failure and loosening (OR 0.79, CI 0.37-1.66, I2 = 29%, p = 0.22), all causes of re-revision (OR 1.03, CI 0.73-1.44, I2 = 0%, p = 0.56) and aseptic revision (OR 0.74, CI 0.27-2.02, I2 = 0%, p = 0.41) between cemented and hybrid techniques. Functional and pain outcomes compared between the two fixation techniques were largely similar across the studies included in this meta-analysis. CONCLUSION: Despite a trend favouring hybrid stems in revision TKA, current evidence revealed that radiological outcomes and re-revision rates are largely similar between cemented and hybrid fixation techniques.

Cutibacterium acnes Infection of Hip Bipolar Hemiarthroplasty Resulting in Protrusio Acetabuli: A Case Report and Review of Literature.

Introduction: Hip bipolar hemiarthroplasty is commonly done for elderly patients who suffer from femoral neck fractures, with good functional outcomes. Prosthetic acetabular protrusio is a rare complication following bipolar hemiarthroplasty and can occur in prosthetic joint infections (PJIs) due to destructive osteolysis and resorption of surrounding bone. Among PJI pathogens, Cutibacterium acnes is increasingly being implicated. In our paper, we review the current literature of C. acnes PJIs and report a unique case of C. acnes infection of hip bipolar hemiarthroplasty complicated by protrusio acetabuli. Case Report: The patient is a 77-year-old Asian-Chinese man who suffered from left hip pain 10 years after bipolar hemiarthroplasty surgery. Radiographic evaluation showed acetabular protrusio with extensive femoral osteolysis. Subsequent intraoperative cultures revealed C. acnes infection. The patient successfully underwent antibiotic treatment and a two-staged revision total hip arthroplasty. Conclusion: C. acnes is an increasingly recognized cause of PJIs and can cause significant morbidity. It should not be simply regarded as a contaminant of tissue or cultures. C. acnes PJIs require antibiotic treatment and early surgery with debridement and revision. This reported case presented technical challenges due to the infection resulting in prosthetic acetabular protrusio.

Predictors of failure following fixation of intertrochanteric fractures with proximal femoral nail antirotation

INTRODUCTION@#This retrospective matched case-control study aimed to identify predictors of cut-out following intramedullary nailing of intertrochanteric fractures with the 200-mm Synthes proximal femoral nail antirotation (PFNA).@*METHODS@#609 patients underwent intramedullary nailing for intertrochanteric fractures at our institution between January 2011 and December 2014. 370 patients satisfied the inclusion criteria. There were 20 cases of implant cut-out. Cases and controls were matched using a propensity score-matching method with an m:n ratio, matching the criteria of gender, age and side of operation. Radiographs were assessed to determine fracture classification, fracture reduction quality, tip-apex distance, calcar referenced tip-apex distance (CalTAD), anteroposterior (AP) Parker's ratio index, lateral Parker's ratio index and cervical angle difference. Conditional logistic regression analysis was performed to determine any association between potential predictors and cut-outs.@*RESULTS@#The cut-out incidence was 5.4%. Of the 20 cut-outs, 16 were superior and four were cut-throughs. Univariate analysis only showed a significant association between unsatisfactory fracture reduction quality and cut-outs (odds ratio [OR] 10.1, 95% confidence interval [CI] 1.31-77.6, p = 0.027). This association remained significant with multivariate logistic regression analysis (OR 16.4, 95% CI 1.9-140.4, p = 0.011). Cut-throughs had significantly lower CalTAD (16.2 vs. 27.5, p = 0.016) and AP Parker's ratio index values (38.7 vs. 50.7, p = 0.007) than superior cut-outs.@*CONCLUSION@#Unsatisfactory fracture reduction quality was a significant predictor of cut-out in intertrochanteric fractures treated with the 200-mm PFNA. Cut-outs had two distinct modes, with cut-throughs having a deeper and more inferior helical blade position in the femoral head compared to superior cut-outs.