The most common indication for knee arthrodesis is pain and instability in an unreconstructable knee following an infected knee arthroplasty. In this study, we compare the use of the Mayday arthrodesis nail (Ortho-dynamics, Christchurch, UK) versus external fixation, Orthofix (Berkshire UK) and Stryker Hoffman II (County Cork, Ireland).

All patients in this study underwent arthrodesis between 1995 and 2006 at Conquest Hospital, Hastings. In group A, 11 patients underwent arthrodesis with a Mayday nail. In all cases, the indications were infected total knee replacements (TKR). Three of these patients previously had failed attempts at arthrodesis with external fixation devices. In group B, seven patients underwent arthrodesis using external fixation. In six patients, the indication was infected TKRs. Results were reviewed retrospectively, with union assessed both clinically and radiologically.

The mean inpatient stay for the Mayday nail group was 23 days (range 8 – 45 days) compared with 76 days (range 34 – 122) for the external fixation group (p< 0.01, CI 95). Ten patients in group A went on to confirmed primary arthrodesis. One patient underwent revision arthrodesis with a Mayday nail and subsequently united. In group B only two patients achieved union. The rate of union was significantly greater in the Mayday nail group than the external fixation group (91% vs 29%, p< 0.01). Of those patients that achieved union, there was no difference in the time to fusion between groups.

Our study supported the existing literature and found that the Mayday nail appeared more effective than monoaxial external fixators for arthrodesis in the management of infected total knee replacements.

We retrospectively studied the possibility that direct trauma to the biceps muscle might be the cause of poor elbow flexion and supination in 18 consecutive children with birth lesions of the brachial plexus who had delayed or impaired biceps recovery despite neurophysiological evidence of reinnervation. All had good shoulder and hand function at three months of age. Eight recovered a strong biceps after six months, but nine required a pectoralis minor to biceps transfer to augment elbow flexion and supination. One had a delayed but good recovery of the biceps after microsurgical reconstruction of the plexus. All had a clinical ‘pseudotumour’ in the biceps muscle, which was biopsied during pectoralis minor transfer in two patients and showed rupture and degeneration of muscle fibres with a fibro-fatty infiltrate, suggesting previous muscle trauma.

Direct muscle trauma is an uncommon but important cause of delayed or impaired biceps recovery after brachial plexus birth injuries. Surgery to reinnervate the biceps muscle will not work if substantial muscle damage is present when a suitable muscle transfer should be considered.

The aim of this study was to compare two types of knee arthrodesis.

Fourteen patients underwent arthrodesis of the knee in a single institution. Seven had a customised coupled nail (the Mayday arthrodesis nail), and six had external fixation applied, one patient had both procedures undertaken. Twelve patients had infected knee arthroplasty, one had recurrent dislocation following arthroplasty and one had an infected open meniscetomy. Comparison was made with the external fixation in which only two cases achieved bony union compared with all eight (100%) using the customised nail. Time to bony union was also considerably shorter in the later group, as was the length of hospital stay.

We conclude that a customised intra-medullary nail is a superior method of knee arthrodesis compared with external fixation.

Osteoclasts are cells that resorb bone. They derive from haemopoietic precursors in the presence of Macrophage-Colony Stimulating Factor (M-CSF) and the osteoclast growth factor, Receptor Activator of Nuclear Factor–kB Ligand (RANKL). Tumour Necrosis Factor-a (TNF-a) and M-CSF has been shown to form mature osteoclastic bone resorption in vitro murine cultures in the absence of RANKL. The aim of this study was to investigate the mechanism of action of the pro-inflammatory cytokine Tumour Necrosis Factor-a (TNF-a) with respect to osteoclastic bone resorption. Development of osteoclasts was performed using an in vitro assay of healthy human peripheral blood mononuclear culture (PBMNC) in the presence of M-CSF and RANKL. In the same cultures RANKL was replaced by TNF-a over a wide range of concentrations. Osteoclasts were generated in the presence of M-CSF, TNF-a and RANKL from human PBMNC. However, in the same experiments M-CSF and TNF-a in the absence of RANKL failed to support human osteoclast formation. Aseptic loosening and osteolysis are considered the main long-term complications of hip arthroplasty. Pathogenesis of peri-prosthetic osteolysis is multifactorial and both biological and mechanical factors are important. TNF-a is thought to be involved in orthopaedic implant oste-olysis induced by prosthesis-derived wear particles. The final osteolytic step is undertaken mainly by osteoclasts. This is the first report showing that TNF-a and M-CSF in the absence of RANKL in human PBMNC is not capable of inducing osteoclast formation. TNF-a therefore may increase peri-prosthetic loosening by enhancing the activity of the mature osteoclast.