Less invasive knee replacement procedure

Early in July, Benenden Hospital hosted an innovative bilateral knee replacement operation using the relatively unknown Signature procedure. With traditional knee replacement surgery, surgeons planning a knee replacement operation typically have to plan each operation using information from two-dimensional X-rays. The Signature system takes away this requirement, using computer software to automatically calculate the best mechanical alignment from an MRI scan and producing jigs to achieve this. A further benefit when used in conjunction with the Signature system, the Vanguard Complete Knee System allows orthopaedic surgeons to provide a more customised fit for the patient. The Vanguard knee offers a range of femoral size options, with 90 different size combinations available. To date there have only been around 500 operations undertaken using this technique in the UK, although the procedure is performed regularly in the US. Benefits of the procedure for the patient include minimal disruption, less post-operative pain and a faster recovery time which has, traditionally, been a problem with knee replacement procedures.

Why bilateral?

In cases where a bilateral operation is required, both knee joints will have deteriorated to a stage where the healing of one knee replacement would depend on the opposite knee, making it necessary to replace both joints at the same time. On average, only 5% of orthopaedic patients will have both knee joints replaced simultaneously, as recovery from the operation can be particularly uncomfortable and lengthy. Benenden Hospital, where the most recent bilateral knee replacement operation took place, is an independent hospital that supports the NHS, having the capability to adopt and implement innovative techniques and technologies to provide the latest, most effective surgery, particularly in the field of orthopaedics. Speaking in more detail about the operation, Mr William Dunnet, a specialist orthopaedic surgery consultant at Benenden Hospital said: “It is quite rare for a patient to have both knee joints replaced simultaneously but Benenden Hospital has the facilities to carry this out. We were able to replace both knees in two and a half hours, a fraction longer than it usually takes to replace one knee joint using traditional methods.” Bernard Morel, product manager at Biomet UK, the company supplying the Signature system and the implant, provided more detail on the procedure. He said: “It creates a preoperative plan prior to surgery. The implant can be more accurately positioned and the operation is less invasive. Mr Dunnet then went on to explain the procedure in more detail from a surgeons perspective: “Using the system we firstly need to take an MRI scan of the patients knee, at least six weeks before the procedure. This gives us accurate alignment details of the knee with respect to the hip and the ankle and all other anatomical landmarks. These landmarks are then used to create custom made jigs which allow us to make extremely accurate cuts on the patients bone so that we are able to implant the prosthesis in the best possible position.