Conventional Indications for Unicompartmental Knee Arthroplasty

Surgical management of tibiofemoral osteoarthritis (OA) is debated, with three solutions: high tibial/distal femoral osteotomy (HTO/DFO), total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA). Indications for HTO are declining while those for UKA are increasing, but initial results were poor. UKA is now becoming increasingly popular due to its advantages, such as near-normal kinematic function, preservation of bone stock, less invasive surgery, simpler postoperative follow-up, outpatient surgery, lower morbidity, lower mortality, and better function. The clinical assessment should identify the specific site of pain and four clinical characteristics: good mobility, sagittal stability, patellofemoral mobility, and reducibility of varus deformity. Radiological assessment should include an anterior view with comparative weightbearing views, patellofemoral view at 30°, and long leg view with weightbearing. Osteonecrosis (ON) is a rare condition affecting the femoral condyle in females over 50 years of age, manifested by unilateral sudden-onset pain with no X-ray changes. UKA can be offered, but contraindications include: age <60, overweight, manual worker, patellofemoral osteoarthritis, high frontal deformity, and chondrocalcinosis. UKA use by surgeons is highly variable depending on their country, experience, and trust in the implant. UKA in patients >60 years has good clinical and radiological results, but wear on the PE increases with younger subjects, activity, and follow-up. Age < 60 should not be a contraindication to implant UKA. Chondrocalcinosis is not a real contraindication to UKA, like patellar osteoarthritis (PFOA), exepted in patella subluxation. Overweight patients may be exposed to premature wear of polyethylene. UKA should not be used in patients with BMI > 35 kg/m2. UKA is not contraindicated for secondary OA but can be combined with simultaneous ACL reconstruction with good results. The risk of revision surgery is higher when the annual number of UKA procedures performed by the surgeon is low. “conventional indications” for UKA are too restrictive and should be revised.