Compartmental arthroplasty in the treatment of osteoarthritis of the knee

Abstract

INTRODUCTION: Compartmental Arthroplasty: ipsilateral combinations of partial knee arthroplasty (CPKA), are Anterior Cruciate Ligament (ACL) preserving alternatives to Total Knee Arthroplasty (TKA) in the treatment of osteoarthritis. This thesis investigates the biomechanics, gait characteristics and patient reported outcomes of CPKA.

METHODS: In vitro, the extensor moment, relative implant efficiency and anterior-posterior stability, of cadaveric specimens were determined with varying implant combinations in situ. CPKA subjects were measured on an instrumented treadmill at top walking speeds, then compared to matched healthy and primary posterior-cruciate retaining TKA subjects using the vertical component of ground reaction forces and temporospatial measurements. Finally, satisfaction was determined using the Oxford Knee Score and quality of life was assessed using the EuroQol-5D.

RESULTS: In vitro, UKA and CPKA generated the same extensor moment as native knees at low flexion angles, where TKA were less efficient. In deep flexion, the extensor mechanism was marginally more efficient following TKA than CPKA. Overall efficiency of UKA and CPKA were near-normal but significantly reduced following TKA. UKA and BCA demonstrated normal anterior-posterior stability, whilst Bi-UKA demonstrated increased anterior laxity. TKA were least anterior-posterior stable at all flexion angles. In the gait lab, CPKA subjects recorded faster speeds than TKA counterparts, near-normal weight-acceptance, maximum weight-acceptance force and mid-stance forces. CPKA had longer step and stride lengths, and reported higher OKS and EQ-5D scores.

DISCUSSION: CPKA may be utilised in primary two-compartment disease or for native compartment degeneration in a knee with an existing partial knee implant, through the addition of a partial knee arthroplasty. Conservation of the ACL, healthy bone and peri-articular tissue during CPKA preserves near-native extensor efficiency, anterior-posterior stability, highly functional fast walking, good patient satisfaction and quality of life.

CONCLUSIONS: Emerging evidence suggests that CPKA may be a high-functioning, satisfying alternative to TKA in patients with multi-compartment osteoarthritis.