Knee replacement for patient with Lorian-Dwarfism

Posted on 23 May 2019

Dr Hennie Bester, an orthopaedic surgeon based at Mediclinic George, encountered an unusual case recently. Theo Bosman, a 74-year old resident of George, came to his practice as he required a knee replacement as he was in severe pain. The complication in Theo’s case was that he is a Lorain-dwarf, a condition caused by lack of growth hormones.

According to Dr Bester, Theo is a proportional dwarf, which simply meant that planning had to happen the same as usual – just on a smaller scale. It was important to ensure that the prosthesis selected for him was the appropriate size and fit.

The process for planning such a surgery is key to ensuring the longevity of the prosthesis. Alignment and balancing as well as obtaining the correct size prosthesis are essential. To aid in this planning, computer-generated models are used to build a replica of the real size and shape of the person’s joint. Thanks to the assistance from Smith & Nephew’s Visionaire system, this was possible for the patient. However, all the planning and projecting was done in the USA as this is where the system is based. All the scans of the patient’s right leg were sent to America where the models were produced as well as the planning for cuts.

The process was further complicated by the fact that Theo Bosman suffered a knee injury during an accident in 1982, when a driver skipped a robot and knocked him off his bike. This resulted in him receiving screws in his tibia to repair the damage, which would also have had to be removed during surgery. A further consequence of the accident was deformation and outgrowths on the bone, which had to be removed during the operation.

A traditional knee surgery can last between 1 and 2 hours depending on the difficulty of the procedure. In Theo’s case, the screws had been there more than 30 years. The longer screws are left in the bone the more difficult it is to remove them – they may break during this process.

While the process of selecting the right prosthesis was complicated by the patient’s condition, Dr Bester confirms that it only took a few weeks. He does highlight that because there is a broad range of prosthetics available that vary according to function and requirements, they were able to select the one that best suited the patient.

Dr Bester attributes the selection of the best prosthesis in this case to his working relationship with Smith & Nephew. He acknowledges there are many suppliers in the market but believes that a working relationship with good service is what counts. He said that Smith & Nephew were also willing to assist in terms of managing the costs, which could have been greater because of the complexity of the case.

Fortunately, for Theo, the procedures seems to have gone well. According to Dr Bester, a patient is usually discharged three to four days after surgery and is mobile with the assistance of a crutch. Since the prosthesis is cemented onto the bone, they can bear weight almost immediately. In the post-operative check up about then days after the surgery, Theo had virtually no pain and was able to straighten his knee completely – bending to approximately 100O.  Within four weeks the patient can begin to wean off the crutch with a six week target of walking unaided. Theo’s recovery is expected to follow this path and he is in good spirits following the knee surgery.


Published in Innovation