Patients with severe knee instability remain a surgical challenge. Furthermore, in the presence of extensive bone loss, constrained condylar implants may be unsuitable.

Hinged knee replacements have served an important role in the management of such complex knee pathologies.

A combined prospective and retrospective study of 138 consecutive hinge knee arthroplasties (42 primary and 96 revisions) of 8 different models performed in our institution between 2004 and 2010 at a mean follow up of 4.2years.

Outcomes were reviewed and knee scores preoperatively and postoperatively at 1, 2 and 5 years using the American knee scoring system.

The mean preoperative American knee score of 31 improved to 87 postoperatively.

Complication rate was 19%, 15% of which required re-revisions for: loosening (4%), Infection (4%), periprosthetic fracture (3%), Implant fracture (2%), Component disassembly (1%) and dislocation (1%). Overall implant failure rate was 9% and implant survivorship was greater than 80% at 4 years.

In our study, hinge prostheses provided good stability and symptom relief with a lower complication rate compared to some previous studies.

In addition, we believe hinge prostheses can also serve as reasonable alternatives to amputation and arthrodesis in many complex knees cases.