Akif Ince

The possibility of migration of cementless cups in total joints after prophylaxis of heterotopic ossification with irradiation or nonsteroidal antiinflammatory drugs is a concern. Data investigating component stability with digital methods are lacking. This prospective study analyzed the migration of cementless cups after indomethacin and irradiation prophylaxis with the digital Einzel-Bild-Röntgen-Analyse tool. The irradiation group (106 hips) and the indomethacin group (98 hips) were compared with 82 hips that did not receive any prophylaxis. The same cementless acetabular implants were used in all cases, and patients were observed clinically and radiographically at 2 and 5 years. At the 5-year followup, the number of cups that showed migration greater than 1 mm in the irradiation group (five), the indomethacin group (three), and the control group (four) were not different. No cup was considered loose on the radiographs and no patient underwent revision surgery. The results of our study indicate irradiation or short-course use of indomethacin for prophylaxis of heterotopic ossification did not negatively affect the stability of cementless cups in primary total hip arthroplasties.

Infection of total joint replacements is painful, disabling and difficult to treat because of the increasing bacterial resistance against antibiotics. In view of this, antiseptics show limited bacterial tolerance and have a broad-spectrum antimicrobial activity. However, the application of antiseptics to bone is insufficiently studied in literature. Therefore, we investigated the biocompatibility of the antiseptic polyhexanide with bone related cells and asked whether supplementation to bone cement is appropriate in the management of total arthroplasty infections. We performed an in vitro study with immortalised human foetal osteoblast cells (hFOB 1.19) and human endothelial cells (EAhy 926). The cultured cells were exposed to media containing various concentrations of gentamicin (12.5-800 microg/ml) and polyhexanide (0.0006-0.01%) for six hours. We measured the phase-contrast microscopy images, the cell viability, cell number and the alkaline phosphatase activity as a parameter for osteogenic function. The exposure of hFOB and endothelial cells to polyhexanide showed a severe reduction of viability and cell number. Gentamicin did not have negative effects on hFOB and endothelial cell number and viability. The alkaline phosphatase activity of hFOB showed a significant decrease after exposure to polyhexanide and gentamicin. The viability and the cell number of endothelial cells seem more negatively affected by polyhexanide than the parameters of the hFOB-cells. The exposure of human osteoblasts and endothelial cells to polyhexanide at concentrations with questionable antibacterial activity resulted in severe cell damage whereas exposure to high dosed gentamicin did not. These results raise questions as to the feasibility of using antiseptics in bone cement for the treatment of total arthroplasty infections. Further in vivo studies are necessary to show the in vivo relevance of these in vitro findings.

Background Minimally invasive approaches to the hip show promise of less muscle trauma compared to conventional approaches. What is the risk of damage to the superior gluteal nerve? We studied the course of the superior gluteal nerve. Method 20 legs of 11 formalin-fixed Caucasian cadavers were dissected and the course and the distances of the superior gluteal nerve branches from the tip of the greater trochanter were documented. Results The branch of the gluteal superior nerve leading to the gluteal minimus muscle was 33 (20–50) mm from the tip of the greater trochanter, within a deeper layer. The nearest point of the superior gluteal nerve branches from the tip of the greater trochanter in the posterior region was 19 (10–30) mm, in the middle region 20 (20–30) mm and in the anterior region 20 (10–35) mm. In half of the cases, a distal intermuscular branch between gluteal medius and tensor fasciae latae muscle could be found, mean 27 (10–40) mm caudal and 38 (25–60) mm ventral to the tip of the greater trochanter. This distal branch is considered to create a loop with upper branches of the superior gluteal nerve within the tensor fasciae muscle. Interpretation The safe zone for the superior gluteal nerve was smaller than previously reported. Use of a minimal direct lateral approach puts the inferior branches within the gluteal medius at risk; however, a minimal anterolateral approach to the hip may compromise branches of the superior gluteal nerve to the tensor fasciae latae muscle.

Local delivery of gentamicin is an accepted method of infection prophylaxis in the surgery of open fractures. However, the few reports of studies into the effect of locally applied gentamicin on osteoblasts used inadequate methods. In our study, we used the well-characterised C2C12 cell line with reproducible differentiation pathway into the osteoblast lineage. We investigated the viability, cell number, alkaline phosphatase activity, and the expression of osteogenic genes of C2C12 cells after exposure to gentamicin at concentrations of 12.5–800 μg/ml for 48 h. Exposure of C2C12 cells to gentamicin (12.5–800 mg/ml) for 48 h showed no significant changes in the cell number, but cell viability was decreased by one-third at the tested concentrations of 200–800 μg/ml. The alkaline phosphatase activity was significantly decreased by one-third to one-half at any tested concentration (12.5–800 μg/ml) of gentamicin. Any tested concentration of gentamicin up to 800 μg/ml for 48 h did not inhibit or decrease the osteogenic gene expression of osterix and alkaline phosphatase of the C2C12 cells. In conclusion, gentamicin at high concentrations as achieved by local application reduced cellular viability and alkaline phosphatase activity in vitro and therefore may be detrimental for bone healing and repair in vivo.

There are few reports in the literature of the diagnosis and treatment of the infected shoulder arthroplasty. Most deal with resection arthroplasty and two-stage exchange surgery. We present our results of one-stage exchange operation as treatment for the infected shoulder arthroplasty. Our group comprised 16 patients (ten men, six women) with 16 infected arthroplasties. By the time of follow-up, two patients had died (mean 5.8 years), two could not be located and three had already undergone revision surgery. Nine patients were thus available for clinical examination and assessment. The infections were largely caused by staphylococci, Propionibacterium species and streptococci. Two were early infections (within three months of surgery) and 14 were late infections. The mean follow-up was 5.8 years (13 months to 13.25 years) when the mean Constant-Murley score was 33.6 points and the mean University College of Los Angeles score 18.3 points. Further revision was performed in three patients. One sustained a peri-prosthetic humeral fracture, another developed an acromial pseudarthrosis after transacromial surgery and the third suffered recurrent dislocations. No patient had a recurrence of infection. A one-stage exchange procedure using antibiotic-loaded bone cement eradicated infection in all our patients and we suggest that such a procedure is at least as successful as either a resection arthroplasty or a two-stage exchange in the management of the infected shoulder arthroplasty.

Background. Loosening of the prosthetic cup is the limiting factor in the service life of total hip prostheses (THPs). Despite effective culture meth

The first documented case of knee alloarthroplasty infection due to Abiotrophia defectiva, formerly known as nutritionally variant streptococci (NVS) and Streptococcus defectivus, is presented. The microbiology of this bacterium is discussed and clinical features of previously reported cases of infections by NVS are reviewed briefly.