Singapore, 8 April 2022 – Instead of a partial or total knee replacement surgery, a growing number of patients are opting for knee preservation surgeries at the Singapore General Hospital (SGH) to treat moderate knee osteoarthritis, a degenerative condition of the joint that is commonly associated with knee malalignment, ageing, being overweight and sports injuries.
The number has jumped twofold from nearly 50 cases in 2020 to about 100 cases last year. With an ageing population, as well as an increase in the prevalence of obesity in the country, the number is set to surpass that of 2021’s.
“Knee implants used in partial or total knee replacement surgery may not be an ideal solution for younger patients as they may need another implant in their lifetime. A knee preservation surgery, however, not only addresses their knee osteoarthritis problem, but may also help patients delay or even avoid the need for a knee replacement surgery in the future,” said Dr Lee Kong Hwee, Consultant, Department of Orthopaedic Surgery and Director, Sport Service, SGH. He also spearheads the Hospital’s Knee Preservation Service set up in 2019.
In Singapore, more than 10 per cent of the adult population suffers from knee osteoarthritis, with a sharp spike in numbers for those between the ages of 40 and 60 – this particular age group stands to benefit the most from knee preservation surgeries.
Two of such surgeries that are commonly performed at SGH include the Modified High Tibial Osteotomy (HTO) and Proximal Fibular Osteotomy (PFO). These are options for patients who suffer from medial compartment osteoarthritis - about one-third of all knee osteoarthritis cases seen at the Hospital. With medial knee osteoarthritis, patients typically only feel pain in the inner part of the knee due to the worn-out cartilage that covers the ends of the thigh bone (femur) and shin bone (tibia). As a result, the bones rub against each other at the joint, causing the pain.
Modified High Tibial Osteotomy (HTO)
Using a specialised saw, the surgeon creates a wedge-shape opening in the upper portion of the shin bone via a small incision of 4 cm. The size and location of the opening needed to achieve optimal knee alignment and function are predetermined with a digital orthopaedic templating software. A bone graft wedge, instead of traditionally used bone graft chips, is then inserted into the opening and secured in place with a titanium plate and screws to realign the knee and takes pressure off the damaged portion of the knee joint. The plate is smaller than what is used in a conventional HTO.
Since the introduction of modified HTO in SGH in June 2019, patients’ recovery time has been halved to two to three months as compared to a traditional HTO.
Proximal Fibular Osteotomy (PFO)
Not all patients, however, can tolerate metal objects in their bodies. For those with severe skin dermatitis, poorly controlled diabetes and poor immunity, it may compromise the outcome of the operation due to higher risk of infection and poorer recovery. There are also patients who prefer a much shorter recovery period. PFO, a simple surgery without implants, may be an option for them.
The surgeon removes 2 cm of the patient’s calf bone (fibula) to disconnect the support to the outer part of the knee. This allows for equal distribution of weight across the entire knee joint, alleviating pain in the process. Patients will be discharged and be able to walk on the same day.
PFO was introduced in SGH in October 2020, and eight in 10 patients who have undergone the procedure are satisfied with the outcome, feeling lesser or no pain in their knee.
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