The knee can be divided into three joints; medial or inside, lateral or outside, and patello-femoral or kneecap joint. If the kneecap joint alone is affected by arthritis then an artificial joint can replace this part. Trochlear dysplasia is a common precursor of patellofemoral arthritis and may account, in part, for persistent anterior knee pain. The surgical options for these patients are arthroscopic debridement, patellofemoral replacement, total knee replacement, or, rarely, patellectomy.
1. Degenerative osteoarthritis limited to the patellofemoral joint
2. Symptoms are severe affecting the daily activity referable to patellofemoral joint degeneration, no response to the lengthy nonsurgical options and / or failed prior conservative procedures
3. Post traumatic osteoarthritis
4. Extensive Grade 3 chondrosis
5. Failed extensor unloading procedure
6. Patellofemoral malalignment / dysplasia induced degeneration with or without instability
Procedure of Patellectomy Replacement:
The kneecap is resurfaced with a plastic button, and a metallic shield is placed in the "trochlear groove" of the thighbone. This procedure is reserved for patients whose arthritis is confined to the patellofemoral compartment, ie the kneecap and the underlying thighbone. A patellofemoral joint implant is a fraction of the size of a total knee replacement, and therefore allows maximal bone preservation, which is vital, especially in younger patients. There is less of a surgical dissection, the time spent in the hospital is shorter, the motion is better.
Patellofemoral replacement ( "kneecap replacement", patellofemoral arthroplasty) is one type of minimally invasive knee surgery. The components are very small compared to a standard total knee replacement.