Aims. The primary objective of this study was to compare migration of the cemented ATTUNE fixed bearing cruciate retaining tibial component with the cemented Press-Fit Condylar (PFC)-sigma fixed bearing cruciate retaining tibial component. The secondary objectives included comparing clinical and radiological outcomes and Patient Reported Outcome Measures (PROMs). Methods. A single blinded randomized, non-inferiority study was conducted including 74 patients. Radiostereometry examinations were made after weight bearing, but before hospital discharge, and at three, six, 12, and 24 months postoperatively. PROMS were collected preoperatively and at three, six, 12, and 24 months postoperatively. Radiographs for measuring radiolucencies were collected at two weeks and two years postoperatively. Results. The overall migration (mean maximum total point motion (MPTM)) at two years was comparable: mean 1.13 mm (95% confidence interval (CI), 0.97 to 1.30) for the ATTUNE and 1.16 mm (95% CI, 0.99 to 1.35) for the PFC-sigma. At two years, the mean backward tilting was -0.43° (95% CI, -0.65 to -0.21) for the ATTUNE and 0.08° (95% CI -0.16 to 0.31), for the PFC-sigma. Overall migration between the first and second postoperative year was negligible for both components. The clinical outcomes and PROMs improved compared with preoperative scores and were not different between groups. Radiolucencies at the implant-cement interface were mainly seen below the medial baseplate: 17% in the ATTUNE and 3% in the PFC-sigma at two weeks, and at two years 42% and 9% respectively (p = 0.001). Conclusion. In the first two postoperative years the initial version of the ATTUNE tibial component was not inferior with respect to overall migration, although it showed relatively more backwards tilting and radiolucent lines at the implant-cement interface than the PFC-sigma. The version of the ATTUNE tibial component examined in this study has subsequently undergone modification by the manufacturer. Level of Evidence: 1 (randomized controlled clinical trial). Cite this article: Bone Joint J 2020;102-B(9):1158–1166

Primary total knee arthroplasty (TKA) is a reliable procedure with reproducible long-term results. Nevertheless, there are conditions related to the type of patient or local conditions of the knee that can make it a difficult procedure. The most common scenarios that make it difficult are discussed in this review. These include patients with many previous operations and incisions, and those with severe coronal deformities, genu recurvatum, a stiff knee, extra-articular deformities and those who have previously undergone osteotomy around the knee and those with chronic dislocation of the patella.

Each condition is analysed according to the characteristics of the patient, the pre-operative planning and the reported outcomes.

When approaching the difficult primary TKA surgeons should use a systematic approach, which begins with the review of the existing literature for each specific clinical situation.

Cite this article: Bone Joint J 2015;97-B(10 Suppl A):30–9.

Total knee arthroplasty (TKA) is an established and successful procedure. However, the design of prostheses continues to be modified in an attempt to optimise the functional outcome of the patient.

The aim of this study was to determine if patient outcome after TKA was influenced by the design of the prosthesis used.

A total of 212 patients (mean age 69; 43 to 92; 131 female (62%), 81 male (32%)) were enrolled in a single centre double-blind trial and randomised to receive either a Kinemax (group 1) or a Triathlon (group 2) TKA.

Patients were assessed pre-operatively, at six weeks, six months, one year and three years after surgery. The outcome assessments used were the Oxford Knee Score; range of movement; pain numerical rating scales; lower limb power output; timed functional assessment battery and a satisfaction survey. Data were assessed incorporating change over all assessment time points, using repeated measures analysis of variance longitudinal mixed models. Implant group 2 showed a significantly greater range of movement (p = 0.009), greater lower limb power output (p = 0.026) and reduced report of ‘worst daily pain’ (p = 0.003) over the three years of follow-up. Differences in Oxford Knee Score (p = 0.09), report of ‘average daily pain’ (p = 0.57) and timed functional performance tasks (p = 0.23) did not reach statistical significance. Satisfaction with outcome was significantly better in group 2 (p = 0.001).

These results suggest that patient outcome after TKA can be influenced by the prosthesis used.

Cite this article: Bone Joint J 2015;97-B:64–70.