Patellofemoral replacement is an operation to replace only the joint surface between the kneecap and the thighbone, preserving the rest of the knee. It is performed for isolated patellofemoral arthritis.
An incision is made over the front of the knee. The damaged surfaces of the trochlear groove (on the femur) and the underside of the patella are replaced with metal and plastic components. The rest of the knee joint is left intact. The operation takes approximately one to one and a half hours.
Patellofemoral replacement is suitable for patients with isolated arthritis of the patellofemoral compartment who have preserved cartilage in the medial and lateral compartments. It is an alternative to total knee replacement with the advantage of preserving more normal knee mechanics.
Physiotherapy, weight management, activity modification, and injections. Total knee replacement is the main surgical alternative.
Standard pre-assessment. X-rays and MRI to confirm isolated patellofemoral disease.
Good pain relief with preservation of more normal knee movement and proprioception compared to total knee replacement. Most patients report the knee feels more 'natural' than after TKR.
Some patients continue to have anterior knee discomfort.
Expected initially.
The remaining compartments may develop arthritis, requiring conversion to TKR.
Component loosening over time.
Patellar maltracking with the new components.
Joint infection approximately 1%.
DVT despite preventive measures.
General or spinal anaesthesia.
Hospital stay one to two days. Early mobilisation. Physiotherapy for quadriceps strengthening. Driving at four to six weeks. Full recovery three to six months.
Reviews at two weeks, six weeks, three months, and one year.
If arthritis is isolated to the patellofemoral joint, a partial replacement preserves more of the knee and typically provides a more natural-feeling result with faster recovery.
If the remaining compartments develop arthritis, the patellofemoral replacement can usually be converted to a total knee replacement.