Progressive degenerative changes in the medial compartment of the knee following lateral unicompartmental arthroplasty (UKA) remains a leading indication for revision surgery. The purpose of this study is to evaluate changes in the congruence and joint space width (JSW) of the medial compartment following lateral UKA. The congruence of the medial compartment of 53 knees (24 men, 23 women, mean age 13.1 years; sd 62.1) following lateral UKA was evaluated pre-operatively and six weeks post-operatively, and compared with 41 normal knees (26 men, 15 women, mean age 33.7 years; sd 6.4), using an Interactive closest point algorithm which calculated the congruence index (CI) by performing a rigid transformation that best aligns the digitised tibial and femoral surfaces. Inner, middle and outer JSWs were measured by sub-dividing the medial compartment into four quarters on pre- and post-operative, weight bearing tunnel view radiographs. The mean CI of knees following lateral UKA significantly improved from 0.92 (sd 0.06) pre-operatively to 0.96 (sd 0.02) (p < 0.001) six weeks post-operatively. The mean CI of the healthy control group was 0.99 sd 0.01. Post-operatively, the mean inner JSW increased (p = 0.006) and the outer decreased (p = 0.002). The JSW was restored post-operatively as no significant differences were noted in all three locations compared with the control group (inner JSW p = 0.43; middle JSW p = 0.019, outer JSW p = 0.51).

Our data suggest that a well conducted lateral UKA may improve the congruence and normalise the JSW of the medial compartment, potentially preventing progression of degenerative change.

Cite this article: Bone Joint J 2015;97-B:50–5.

Aims. Knee joint distraction (KJD) is a relatively new, knee-joint preserving procedure with the goal of delaying total knee arthroplasty (TKA) in young and middle-aged patients. We present a randomised controlled trial comparing the two. Patients and Methods. The 60 patients ≤ 65 years with end-stage knee osteoarthritis were randomised to either KJD (n = 20) or TKA (n = 40). Outcomes were assessed at baseline, three, six, nine, and 12 months. In the KJD group, the joint space width (JSW) was radiologically assessed, representing a surrogate marker of cartilage thickness. Results. In total 56 patients completed their allocated treatment (TKA = 36, KJD = 20). All patient reported outcome measures improved significantly over one year (p < 0.02) in both groups. At one year, the TKA group showed a greater improvement in only one of the 16 patient-related outcome measures assessed (p = 0.034). Outcome Measures in Rheumatology-Osteoarthritis Research Society International clinical response was 83% after TKA and 80% after KJD. A total of 12 patients (60%) in the KJD group sustained pin track infections. In the KJD group both mean minimum (0.9 mm, standard deviation (. sd. ) 1.1) and mean JSW (1.2 mm, . sd. 1.1) increased significantly (p = 0.004 and p = 0.0003). Conclusion. In relatively young patients with end-stage knee osteoarthritis, KJD did not demonstrate inferiority of outcomes at one year when compared with TKA. However, there is a high incidence of pin track infection associated with KJD. Cite this article: Bone Joint J 2017;99-B:51–8

Aims

The primary objective of this study was to compare the five-year tibial component migration and wear between highly crosslinked polyethylene (HXLPE) inserts and conventional polyethylene (PE) inserts of the uncemented Triathlon fixed insert cruciate-retaining total knee arthroplasty (TKA). Secondary objectives included clinical outcomes and patient-reported outcome measures (PROMs).