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. Patients and Methods. From January 2008 to July 2009, 99 patients were enrolled and randomly divided into two groups, those having a Mobi-C implant (n = 51; 30 men, 21 women) and those undergoing ACDF (n = 48; 28 men, 20 women).The patients were followed up for five years, with the primary outcomes being the Japanese Orthopaedic Association score, visual analogue scale for pain and the incidence of further surgery. The secondary outcomes were the Neck Disability Index and range of movement (ROM) of the treated segment. Results. The incidence of further surgery was found to be statistically significant between the two groups (p = 0.49), with seven ACDF patients requiring further surgery and only one Mobi-C patient requiring re-operation. There were significant differences (p < 0.001) between the two groups in the ROM of the treated segment. However, both Mobi-C surgery and ACDF surgery were effective in improving the patient’s clinical symptoms. Take home message: Mobi-C implant surgery is a safe alternative to ACDF surgery in cervical disc degeneration. Cite this article: Bone Joint J 2016;98-B:829–3

Purpose of the study: Discectomy-anterior fusion has proven efficacy for many diseases of the cervical spine. Nevertheless, the loss of motion and the over-solicitation of adjacent levels are arguments in favor of disc replacement. This prospective study examined the early clinical and radiological results obtained in the first 41 patients treated with a new cervical disc prosthesis, Mobi-C. Material and methods: A prospective multicentric clinical and radiological study is being conducted to analyze the safety and efficacy of Mobi-C for degenerative disease. Indications are radiculopathies due to discal herniation or foraminal osteophytic stenosis involving one or two levels from C3 to T1. An independent observer reviewed the patients. SF36, the Neck Disability Index, and a visual analogue scale for pain as well as radiographic mobility were noted. Results: Mean age was 42 years (range 31–56 years). There were 23 men and 18 women. Eight patients had two disc replacements. Mean follow-up was six months (range 3–10 months). Mean operative time was 65 min, similar to operative time for fusion. Blood loss was 90 ml. NSAID were prescribed for the first 15 days. There were no intraopeartive complications and no revisions. Postoperative complications were minimal. There were no specific complications related to the prosthesis, its insertion or its function. The function and quality-of-life scores showed a significant improvement at last follow-up. Radiographically, motion was also improved in most patients. Discussion: The early results on the safety and efficacy of this new cervical prosthesis are promising. Primary stability has been excellent and there have been no specific prosthesis-related complications. Furthermore, several operators have mentioned how easy it is to insert the Mobi-C. Conclusion: The clinical results in terms of pain and function as well as the radiological results have been satisfactory both at the early and at the later assessments. Insertion of this prosthesis is a simple process, similar to insertion of an intersomatic cage, elements arguing in favor of a cervical disc prosthesis. Further follow-up will be needed to assess the long-term efficacy and possible effect on prevention of accelerated degeneration of the adjacent discs