Lateral unicompartmental knee arthroplasty: A review

Abstract

Isolated lateral compartment osteoarthritis of the knee is a rare condition affecting approximately 1% of the population, which is ten times less common than osteoarthritis affecting only the medial compartment. Unicompartmental knee arthroplasty (UKA) has many potential advantages over total knee arthroplasty. The benefits of UKA include a smaller incision, preservation of more native tissue (including cruciate ligaments and bone), decreased blood loss, and better overall proprioception. When UKA was first introduced in the 1970s, the outcomes of medial UKA (MUKA) were poor, but the few cases of lateral UKA (LUKA) showed promise. Since that time, there has been a relative paucity of literature focused specifically on LUKA given it is a rare procedure. Refinements in patient selection criteria, implant design, and surgical technique have been made leading to increased popularity. A review of the recent literature reveals that LUKA is associated with excellent long-term clinical outcomes and implant survivorship when performed in properly selected patients. Implant design options include fixed vs mobile bearing as well as metal backed vs all polyethylene tibial component, with improved outcomes noted with fixed bearing designs. Three reasons cited for revision ( i.e. , fracture of the femoral component, fracture of the tibial component, and valgus malalignment) had been reported in past literature but not recently. Presently, while rare, the most common cause of failure and need for revision are osteoarthritis progression and aseptic loosening. Despite the need for an occasional revision procedure, the survivorship of LUKA is comparable to MUKA, although it should be noted that outcomes of MUKA have been notably varied. Continued pursuit of improved techniques and implant designs will continue to show LUKA to be an excellent procedure for appropriately indicated patients.

Survival of lateral unicompartmental knee arthroplasty at short‐, mid‐, and long‐term follow‐up: a systematic review and meta‐analysis

“…The rarity of lateral UKA performed (10 times less frequently than its medial counterpart) results in an insufficient body of literature available regarding this procedure. 1 The role of lateral UKA has been inconclusive. This present study contributes to the current literature by performing a meta-analysis of survival data of lateral UKA alone at short-, mid-, and long-term follow-ups.…”

“…Unicompartmental knee arthroplasty (UKA) acts as an appealing alternative to total knee arthroplasty (TKA) for the treatment of isolated knee osteoarthritis (OA). 1 Its potential advantages over TKA include smaller incisions, faster rehabilitation, shorter hospital stay, better functional outcomes, and lower occurrences of complication as well as mortality. [2][3][4] UKA In contrast to medial UKA which has been widely used, lateral UKA is less frequent, accounting for less than 1% of the total number of knee arthroplasties and about 5%-10% of all UKAs.…”

“…[2][3][4] UKA In contrast to medial UKA which has been widely used, lateral UKA is less frequent, accounting for less than 1% of the total number of knee arthroplasties and about 5%-10% of all UKAs. 1,5 The rarity of isolated lateral knee OA, which is 10 times less common than isolated medial knee OA, 1 could be a factor at play. In addition, lateral UKA is considered to be more technically challenging owing to its anatomic and biomechanical characteristics.…”

“…Unicompartmental knee arthroplasty (UKA) acts as an appealing alternative to total knee arthroplasty (TKA) for the treatment of isolated knee osteoarthritis (OA) 1 . Its potential advantages over TKA include smaller incisions, faster rehabilitation, shorter hospital stay, better functional outcomes, and lower occurrences of complication as well as mortality 2–4 .…”

Similar survivorship at the 5-year follow-up comparing robotic-assisted and conventional lateral unicompartmental knee arthroplasty

“…The indications for surgery were as follows: Kellgren–Lawrence of the lateral compartment grade III or IV OA; avascular necrosis or osteonecrosis isolated of the lateral femoral condyle; idiopathic or secondary osteoarthritis of the lateral femoral compartment of the knee; knee flexion > 100°; flexion contracture < 15°; valgus deformity (measured on hip–knee–ankle angle) < 10°; integrity of cruciate and collateral ligaments; osteoarthritis of the medial compartment and patellofemoral grade I or II according to Kellgren–Lawrence classification [ 5 ].…”