Treatment of osteoarthritis is evolving, allowing more options of surgical intervention at an earlier stage. The interpositional knee device is a recently developed patient specific implant used for the treatment of uni-compartmental osteoarthritis. It is designed for use in mild to moderate osteo-arthritis only. The benefits it offers are, that it is less invasive than traditional methods, can be performed as a day procedure and does not limit future options.

Young adults with uni-compartmental arthritis are suitable for this implant. A MRI scan of the patient's knee is reviewed by radiologists to decide if the patient is suitable. A bespoke implant, based on the MRI data, is produced. Prior to insertion an arthroscopy is undertaken to allow proper positioning of the implant.

We have treated 26 patients with the iForma Conformis interpositional knee implant in South Wales at the Princess of Wales Hospital, Bridgend and the Royal Glamorgan Hospital, Llantrisant since November 2007. The pre- and post-operative WOMAC scores were recorded. Average age was 54.7 years, BMI 32; 9 females and 17 males. The average pre-operative WOMAC score was 42.2 with an improvement to 62.9. 33 implants were used (19 right, 14 left). 7 patients experienced post-operative problems (5 implants removed and 2 MUAs). No dislocations were reported. Average follow-up time was 12.6 months (range 6-26 months).

Our early experience suggests patient selection plays a vital role in the outcome of patients following surgery. It indicates that the interpositional knee device is a viable and safe alternative to a uni-compartmental knee replacement.

Treatment of osteoarthritis is evolving, allowing surgical treatment options at an earlier stage. The interpositional knee device is a recently developed patient specific implant used for the treatment of mild to moderate uni-compartmental osteoarthritis. The benefits over traditional methods of surgical management are: it's less invasive, can be a day procedure and does not limit future options. Young Adults with early uni-compartmental arthritis are suitable. A MRI scan of the patient's knee is reviewed by radiologists to decide if the patient is suitable. A bespoke implant is produced. Prior to insertion an arthroscopy is undertaken to allow proper positioning.

We treated 27 patients with the iForma Conformis interpositional knee implant in South Wales at the Princess of Wales Hospital, Bridgend and the Royal Glamorgan Hospital, Llantrisant since November 2007. The pre- and post-operative WOMAC scores were recorded. The average age was 54.7 years, BMI 32; 10 females and 20 males. The average pre-operative WOMAC score was 42.2 improving to 62.9 post-operatively. 35 implants were used. 7 patients experienced post-operative problems. No dislocations were reported. Average follow-up was 12.6 months.

Our early experience suggests patient selection plays a role in the outcome following surgery. It indicates that this device is a viable and safe alternative to a uni-compartmental knee replacement.