Impact of unplanned second debridement, antibiotics and implant retention on long-term outcomes in knee exchange arthroplasty: Elevated risk of failure and reinfection.

Purpose: This study investigates the outcomes of two-stage exchange arthroplasty (EA) for periprosthetic joint infection (PJI) following initial or unplanned repeat debridement antibiotics, and implant retention (DAIR). Methods: We retrospectively reviewed cases of knee arthroplasty infection treated with two-stage EA after DAIR, spanning from January 1994 to December 2010. A total of 138 patients were included, comprising 112 with initial DAIR and 26 with an unplanned second DAIR. Data on demographics, comorbidities, infection characteristics and causative organisms were analyzed. The primary outcome was implant failure or reinfection, observed over a minimum follow-up of 10 years. Results: The overall success rate for two-stage EA was 87% (119/138 patients). Factors identified for treatment failure included reinfection with the same pathogen for unplanned second DAIR (hazard ratio [HR] = 3.41; 95% confidence interval [CI] = 1.35-4.38; p = 0.004), higher reinfection rates in patients undergoing EA after an unplanned second DAIR, especially with a prior history of PJI within 2 years (HR = 4.23; 95% CI = 2.39-5.31; p = 0.002), pre-first DAIR C-reactive protein (CRP) levels over 100 mg/dL (HR = 2.52; 95% CI = 1.98-3.42; p = 0.003) and recurrence with the same pathogen (HR = 2.35; 95% CI = 1.32-4.24; p = 0.007). Additional factors such as male gender (HR = 3.92; 95% CI = 1.21-5.25; p = 0.007) and osteoporosis (T score < -2.5; HR = 3.27; 95% CI = 1.23-5.28; p = 0.005) were identified as risk factors for implant failure in all EA cases. Conclusions: This study identifies key risk factors for worse knee EA outcomes following DAIR, including a pre-first DAIR CRP level over 100 mg/L, same pathogen recurrence, and PJI history within 2 years. It shows implant failure rates remain constant across EA cases, regardless of DAIR sequence, particularly with risk factors like male gender and severe osteoporosis (T score < -2.5). These results underscore the need for careful evaluation before an unplanned second DAIR, given its significant impact on EA success. Level of Evidence: Level III.

Clinical outcomes of various types of revision surgeries after unicompartmental knee arthroplasty failure.

PURPOSE: The advantages of unicompartmental knee arthroplasty (UKA) have led to the procedure being increasingly performed worldwide. However, revision surgery is required after UKA failure. According to the literature review, the choice of implant in revision surgery remains a debatable concern. This study analyzed the clinical results of different types of prostheses used in treating failed UKA. MATERIALS AND METHODS: This is a retrospective review of 33 failed medial UKAs between 2006 and 2017. Demographic data, failure reason, types of revision prostheses, and the severity of bone defects were analyzed. The patients were classified into three groups: primary prosthesis, primary prosthesis with a tibial stem, and revision prosthesis. The implant survival rate and medical cost of the procedures were compared. RESULTS: A total of 17 primary prostheses, 7 primary prostheses with tibial stems, and 9 revision prostheses were used. After a mean follow-up of 30.8 months, the survival outcomes of the three groups were 88.2%, 100%, and 88.9%, respectively (P = 0.640). The common bone defect in tibia site is Anderson Orthopedic Research Institute [AORI] grade 1 and 2a (16 versus 17). In patients with tibial bone defects AORI grade 2a, the failure rates of primary prostheses and primary prostheses with tibial stems were 25% and 0%, respectively. CONCLUSIONS: The most common cause for UKA failure was aseptic loosening. The adoption of a standardized surgical technique makes it easier to perform revision surgeries. Primary prostheses with tibial stems provided higher stability, leading to a lower failure rate due to less risk of aseptic loosening in patients with tibial AORI grade 2a. In our experience, we advise surgeons may try using primary prostheses in patients with tibial AORI grade 1 and primary prostheses with tibial stems in patients with tibial AORI grade 2a.

Nontuberculous mycobacteria peri-prosthetic joint infection: An outcome analysis for two stage revision arthroplasty.

PURPOSE: Nontuberculous mycobacteria periprosthetic joint infection (NTMPJI) is a rare complication of hip or knee joint arthroplasty. The experience for outcomes of NTMPJI treatment is still limited. The objective of this study was to investigate the outcome of hip or knee nontuberculous mycobacteria periprosthetic joint infection following treatment with two-stage exchange arthroplasty. MATERIAL AND METHODS: From 1995 to 2020, 12 patients with NTMPJI were treated with two-stage exchange arthroplasty at our institution. We collected and analyzed variables including demographic data, comorbidity, microbiological data, treatment outcome and antibiotic formula in bone cement. RESULTS: Mycobacterium abcessus (n = 6) and Mycobacterium chelonae (n = 2) constitute the majority of the cases. Five patients had early-onset PJIs and the other seven patients were late onset. The success rate of two-stage exchange arthroplasty was 66.7% (8 of 12). Three patients experienced infection relapse, and one patient had soft tissue compromise complication. Post-operative antibiotic therapy may not improve the success rate (4 of 6 cases, 66.7%). Based on in vitro study, the most commonly used effective antibiotic in bone cement spacer for nontuberculous mycobacteria was amikacin. CONCLUSIONS: nontuberculous mycobacteria is a rare cause of PJIs and should be suspected especially in relatively immunocompromised patients. Resection arthroplasty with staged reimplantation is the preferred approach. Prolonged post-operative antibiotic therapy before reimplantation may not improve the success rate. Delayed revision surgery may not be needed and can be performed once C-reactive protein level is normal after a drug holiday.

Surgical treatment of femoral head fractures.

BACKGROUND: Femoral head fractures (FHF) are uncommon and generally caused by high-energy injuries. Surgical reduction with stable fixation of large fragments is believed to have the best outcomes. This retrospective study intended to report outcomes with surgical treatment at our institution and tried to establish treatment algorithm. METHODS: Through the 6-year period (2003-2008), 35 FHF in 35 consecutive patients (average, 30 years) were surgically treated. All FHF were caused by high-energy trauma. Patients' general condition was stabilized first and hip dislocation was manually reduced immediately. Definite fracture treatment was scheduled after admission for an average of 2.9 days (0.3-11 days). Pipkin classification was used as the treatment guide and open reduction with internal fixation was performed in all 35 FHF. RESULTS: These FHF included 21 type I, 7 type II, 3 type III, and 4 type IV fractures. The hip joint had been approached by either an anterior or posterior route depending on the individual surgeon. Internal fixation with screws was performed for all 35 FHF. The average admission was 13.8 days (range, 2-35 days). Thirty patients (86%, 30/35) were followed for an average of 3.3 years (at lease 6 months) and all 30 FHF healed. Avascular necrosis of the femoral head was found in 23% (7/30) patients and six patients were converted to hip arthroplasty for developing advanced stages of avascular necrosis. Heterotopic ossification occurred in 43% (13/30) patients. However, only one patient had range of motion limitation. Besides, one patient had moderate hip osteoarthritis. CONCLUSIONS: FHF are uncommon and generally caused by high-energy injuries. Fracture healing can be attained in all femoral head fractures by using open reduction and screw fixation. Our results by using conventional approaches were associated with high complication rates. Further endeavor to improve the outcome should be taken.

Guided growth for caput valgum in developmental dysplasia of the hip.

This study reported guided growth for caput valgum deformity and subsequent hip development. Ten children with unilateral hip dysplasia had guided growth by one eccentric transphyseal screw at age 9.1 years with minimum 2 years of follow-up. The first change was decreasing articulotrochanteric distance and then increasing physis tilt angle and head-shaft angle by 1.5 years. The center edge angle that was significantly less than the normal side (18.3 vs. 24.8°) preoperatively became comparable between both the hips 2 years later. Rebounding of physis inclination after screw back out suggested mechanical tethering, rather than permanent physis closure, resulted in morphologic changes in the femur. LEVEL OF EVIDENCE: Therapeutic study, level IV.

The value of Doppler waveform analysis in predicting major lower extremity amputation among dialysis patients treated for diabetic foot ulcers.

AIMS: This study examined the predictors for lower extremity amputation (LEA) in patients with diabetic foot ulcers according to kidney function and, in the case of dialysis patients, specifically evaluated the vasculature with the ankle-brachial index (ABI) and Doppler waveforms. METHODS: Among 658 diabetic patients admitted to the Diabetic Foot Care Center, 286 had an estimated glomerular filtration rate (eGFR)≥ 60 ml/min per 1.73 m(2), 275 had an eGFR<60, and 97 patients were under maintenance dialysis. All clinical variables were analyzed. A specialist retrospectively reviewed Doppler images of 78 of the patients in dialysis to evaluate peripheral arterial disease. RESULTS: Forty-two percent of patients with eGFR<60 presented with ABI≤0.90. For ABI values>1.40, the proportion of dialysis patients (31.3%) was greater than the proportion of patients with eGFR<60 (5.3%). Wagner wound classifications, reduced serum albumin levels, and low ABI values were the predictors for major LEA among patients in the non-dialysis groups. Nevertheless, these indicators were not predictive of the risk of amputation in diabetic patients on dialysis. The presence of poor monophasic waveforms in the dorsalis pedis artery or posterior tibial artery served as an independent predictor (odds ratio: 7.61; P=0.008) for major LEA among dialysis patients. The sensitivity and specificity were 88.0% and 59.6%, respectively. CONCLUSIONS: Poor monophasic Doppler waveforms of below-the-knee arteries, commonly found among dialysis patients in treatment for diabetic foot ulcers, can serve as an independent predictor for major LEA.