Short stem hip arthroplasty with the optimys prosthesis is a safe and effective option for obese patients: a mid-term follow-up multicenter study.

INTRODUCTION: Short stems are a valuable option in young patients undergoing total hip arthroplasty (THA) because of their bone stock preserving properties facilitating revision hip arthroplasty. Although the effect of obesity on conventional THA is well studied, data about short stem THA in obese patients are lacking. Therefore, this study aimed to investigate the influence of obesity on complications, revisions, and outcome after short stem THA. MATERIALS AND METHODS: This multicenter, observational cohort study included patients undergoing short stem THA with the optimys prosthesis. Follow-up examinations were performed at specific intervals up to 7 years postoperatively. Operation characteristics, general and specific complications, revisions, VAS rest pain, VAS load pain, VAS patient satisfaction, and Harris Hip Score (HHS) were recorded and statistically compared between obese (BMI ≥ 30 kg/m2) and non-obese (BMI < 30 kg/m2) patients. RESULTS: Of the 224 patients included with a mean follow-up of 87.2 months (range 81.9-104.0), 69 were assigned to the OB group and 155 to the non-OB group. A minimally invasive approach was significantly less often selected in obese patients (p = 0.049), whereas operating time and length of hospital stay were not significantly different. The rate of general and specific complications did not significantly differ between both groups. Survival of the optimys prosthesis was 99.1% at 7-year follow-up and one patient per group had to undergo revision surgery. VAS rest pain, load pain, and satisfaction improved from preoperatively to postoperatively in both groups without a significant difference between both groups. While the HHS was improved from preoperatively to postoperatively, obese patients showed a significantly lower HHS at the 7-year follow-up (p = 0.01) but still exhibited an excellent scoring above the PASS threshold. CONCLUSION: Short stem THA with the optimys prosthesis is a safe and effective option also in obese patients with an excellent clinical outcome and a low complication rate.

Prediction of loss of correction after hemiepiphysiodesis for the alignment of lower limb angular deformities.

ABSTRACT: Guided growth by temporary hemiepiphysiodesis (HEPD) is established for the alignment of lower limb angular deformities. This retrospective cohort study was designed to assess the effect of HEPD in idiopathic coronal plane deformities around the knee and on the frontal knee joint line orientation, and to test the frontal knee joint line as predictive means for recurrence.Fourty-four patients (78 deformities: valgus n = 64, varus n = 14) were enrolled in the retrospective observational study. Mechanical axis deviation, mechanical lateral distal femoral angle, and mechanical medial proximal tibial angle were assessed prior to surgery and during follow-up. The facultative frontal knee joint line angle (FKJLA) was used as predictive tool. Cases of remaining growth potential (n = 45/78) after implant removal were followed to assess rebound deformity.Pre-operative angles of the mechanical axis were corrected average 9.0 months after HEPD. Pre-operative assessment of the frontal knee joint line revealed a mean of 3.9° in valgus, and -1.0° in varus deformities. At time of complete deformity correction, mean FKJLA was -0.2° in valgus, and -0.8° in varus deformities. Mean shift of FKJLA was significantly higher after singleHEPD compared to combiHEPD (P < .001). Patients having an unphysiological FKJLA (>/<0°-3°) after correction of mechanical axis had a significantly higher risk of rebound deformity (P = .01). Regression analysis showed a 60.5% higher risk of rebound deformity per each degree deviating from the FKJLA physiological range. Age, gender, or body mass index had no impact.Temporary HEPD offers great potential for the correction of the mechanical axis and the frontal knee joint line. An unphysiological change of the frontal knee joint line is associated with a high risk of recurrent angular deformities. CombiHEPD instead of singleHEPD seems to be safer to prevent detrimental frontal knee joint line shift.Level of Evidence: Retrospective comparative therapeutic study, Level III.

Successful treatment of extensively drug-resistant Pseudomonas aeruginosa osteomyelitis using a colistin- and tobramycin-impregnated PMMA spacer.

Discovered in 1949, the antibiotic colistin was initially used for therapeutic purposes. Parenteral use of colistin was gradually abandoned because of its side-effect profile, especially its nephrotoxicity and neurotoxicity. Despite the risk of these potentially serious adverse effects, increasing resistance of Gram-negative bacteria has led to a renaissance of intravenous use of colistin in the last few years. Local administration of colistin is an alternative method to minimise the risk of systemic toxicity. We present a case of extensively drug-resistant Pseudomonas aeruginosa osteomyelitis treated successfully with high-dose colistin- and tobramycin-impregnated bone cement as a drug delivery vehicle. For the first time, local colistin concentrations in drainage and synovial fluid were quantified in order to determine the optimal dose and to minimise serious side effects. Insertion of a bone cement spacer loaded with a high dose of tobramycin and colistin resulted in local colistin levels at the infection site that exceeded the minimum inhibitory concentration (MIC) of colistin against the isolated P. aeruginosa five-fold on Day 4. Thus, the treatment may be expected to exert a prolonged effect. Whereas systemic administration of colistin alone was not sufficient to treat the infection, combined local and parenteral therapy led to eradication of P. aeruginosa in this patient. Plasma colistin levels remained in the therapeutic range, which confirms the systemic safety of the method.

Thirty-year follow-up after Wagner resurfacing hip arthroplasty: Case report.

Wagner hip arthroplasty has been used as a resurfacing and thereby bone-preserving method for the treatment of disabling osteoarthritis particularly in younger individuals. The underlying rationale was to replace exclusively diseased tissue, to restore anatomy and function and to optimize range of motion and stress transfer to the proximal femur. Wagner's approach was designed to reduce the risk of infection and to make later revisions easier. The technique was however associated with a high revision rate due to early aseptic wear induced component loosening and neck fractures. Nevertheless, we report a case of a 30 years follow-up of a Wagner resurfacing hip arthroplasty.