Aims

In order to evaluate the effectiveness of the Mobi-C implant in cervical disc degeneration, a randomised study was conducted, comparing the Mobi-C prosthesis arthroplasty with anterior cervical disc fusion (ACDF) in patients with single level cervical spondylosis.

We evaluated the efficacy of Escherichia coli-derived recombinant human bone morphogenetic protein-2 (E-BMP-2) in a mini-pig model of spinal anterior interbody fusion. A total of 14 male mini-pigs underwent three-level anterior lumbar interbody fusion using polyether etherketone (PEEK) cages containing porous hydroxyapatite (HA). Four groups of cages were prepared: 1) control (n = 10 segments); 2) 50 μg E-BMP-2 (n = 9); 3) 200 μg E-BMP-2 (n = 10); and 4) 800 μg E-BMP-2 (n = 9). At eight weeks after surgery the mini-pigs were killed and the specimens were evaluated by gross inspection and manual palpation, radiological evaluation including plain radiographs and micro-CT scans, and histological analysis. Rates of fusion within PEEK cages and overall union rates were calculated, and bone formation outside vertebrae was evaluated. One animal died post-operatively and was excluded, and one section was lost and also excluded, leaving 38 sites for assessment. This rate of fusion within cages was 30.0% (three of ten) in the control group, 44.4% (four of nine) in the 50 μg E-BMP-2 group, 60.0% (six of ten) in the 200 μg E-BMP-2 group, and 77.8% (seven of nine) in the 800 μg E-BMP-2 group. Fusion rate was significantly increased by the addition of E-BMP-2 and with increasing E-BMP-2 dose (p = 0.046). In a mini-pig spinal anterior interbody fusion model using porous HA as a carrier, the implantation of E-BMP-2-loaded PEEK cages improved the fusion rate compared with PEEK cages alone, an effect that was significantly increased with increasing E-BMP-2 dosage.

Cite this article: Bone Joint J 2013;95-B:217–23.

Few studies have examined the order in which a spinal osteotomy and total hip replacement (THR) are to be performed for patients with ankylosing spondylitis. We have retrospectively reviewed 28 consecutive patients with ankylosing spondylitis who underwent both a spinal osteotomy and a THR from September 2004 to November 2012. In the cohort 22 patients had a spinal osteotomy before a THR (group 1), and six patients had a THR before a spinal osteotomy (group 2). The mean duration of follow-up was 3.5 years (2 to 9). The spinal sagittal Cobb angle of the vertebral osteotomy segment was corrected from a pre-operative kyphosis angle of 32.4 (SD 15.5°) to a post-operative lordosis 29.6 (SD 11.2°) (p < 0.001). Significant improvements in pain, function and range of movement were observed following THR. In group 2, two of six patients had an early anterior dislocation. The spinal osteotomy was performed two weeks after the THR. At follow-up, no hip has required revision in either group. Although this non-comparative study only involved a small number of patients, given our experience, we believe a spinal osteotomy should be performed prior to a THR, unless the deformity is so severe that the procedure cannot be performed.

Cite this article: Bone Joint J 2014;96-B:360–5.

Between January 1990 and December 2000 we carried out 226 SB Charité III disc replacements for lumbar disc degeneration in 160 patients. They were reviewed at a mean follow-up of 79 months (31 to 161) to determine the clinical and radiological outcome. The clinical results were collected by an independent observer, who was not involved in patient selection, treatment or follow-up, using a combination of outcome measures, including the Oswestry Disability Index. Pain was recorded using a visual analogue score, and the most recent radiographs were reviewed.

Survival of the device was analysed by the Kaplan-Meier method and showed a cumulative survival of 35% at 156 months when radiological failure was taken as the endpoint. The mean improvement in the Oswestry disability index scores after disc replacement was 14% (6% to 21%) and the mean improvement in the pain score was 1.6 (0.46 to 2.73), both falling below the clinically significant threshold. Removal of the implant was required in 12 patients, four because of implant failure.

These poor results indicate that further use of this implant is not justified.