Introduction. When introducing new joint replacement designs, it is difficult to predict with any certainty the clinical performance of the new designs. Using roentgen stereophotogrammetric analysis (RSA) to evaluate the first two years of follow-up can serve as a predictor of late mechanical loosening for hip and knee prostheses. This prospectively randomized study was designed to evaluate the clinical performance of the Triathlon total knee system and compare the results between the two versions; posterior stabilized (PS) and cruciate retaining (CR). Methods. Sixty patients were consecutively randomized (two patients left the study prior to surgery) to receive either the Triathlon total knee PS (30 patients) or the Triathlon total knee CR (28 patients). All components were cemented. The study was approved by the Ethical Committee for Lund University. All patients met the inclusion criteria. There were no statistically significant differences between the demographics for PS and CR. RSA was set to be the principal evaluation parameter. Patient outcome was assessed by the KSS and KOOS questionnaires. Results. There were no statistically significant differences in rotation or translation around or along the three coordinal axes. Neither were there any differences in the maximal total point motion (MTPM) during the 2-year follow-up (p<0.05). There were no statistically significant differences between the clinical results of both groups when using the KSS and the KOOS scoring system (p<0.05). Discussion. There were no clinically significant differences in the RSA 2-year follow-up data, nor in the clinical scores of KSS and KOOS. The results of this study suggest that there is no major differences between the posterior stabilized system and the cruciate retaining system for the Triathlon total knee neither in clinical nor in predictable long term mechanical performance

There is a lack of evidence surrounding selective patella resurfacing, but patella cartilage loss at time of total knee arthroplasty (TKA) is often used as an indication in those who perform it. This study compares the outcomes of TKA without patella resurfacing in patients with and without patella cartilage loss (PFOA). Prospective case control study of 209 consecutive patients undergoing cruciate retaining single radius TKA without patella resurfacing for KL≥3 osteoarthritis. The presence and location of full thickness patella cartilage loss was documented intra-operatively at TKA, identifying n=108 cases with PFOA (mean age 70±9.7, mean BMI 31±6.2, 72 (67%) female) Vs n=101 controls without PFOA (age 68±9.2, BMI31±5.6, 52 (51%) female). Primary outcome measure was improvement in the Oxford Knee Score (OKS) at one year. There were more females in the PFOA group (67% Vs 51%, p=0.037), but no other preoperative differences. There was no difference in preoperative OKS between patients with patella cartilage loss (20.6±7.9) and those without (21.0±7.2, p=0.720). There was no difference in OKS improvement following TKA without patella resurfacing between those with full thickness patella cartilage loss (14.2±9.8) and those without (15.4±9.5, p=0.365). Facet involvement (number and location) did not affect OKSs. No differences were found in the individual OKS questions between groups (p>0.05). There was no difference in one-year OKS or improvements therein between patients with and without full thickness patella cartilage loss treated with single radius cruciate retaining TKA without patella resurfacing, questioning its use an indication for selective patella resurfacing

Anterior knee pain (AKP) is the commonest complication of total knee arthroplasty (TKA). This study aims to assess whether sagittal femoral component position is an independent predictor of AKP after cruciate retaining single radius TKA without primary patellofemoral resurfacing. From a prospective cohort of 297 consecutive TKAs, 73 (25%) patients reported AKP and 89 (30%) reported no pain at 10 years. Patients were assessed pre-operatively and at 1, 5 and 10 years using the short form 12 and Oxford Knee Score (OKS). Variables assessed included demographic data, indication, reoperation, patella resurfacing, and radiographic criteria. Patients with AKP (mean age 67.0 (38–82), 48 (66%) female) had mean Visual Analogue Scale (VAS) Pain scores of 34.3 (range 5–100). VAS scores were 0 in patients with no pain (mean age 66.5 (41–82), 60 (67%) female). Femoral component flexion (FCF), anterior femoral offset ratio, and medial proximal tibial angle all differed significantly between patients with AKP and no pain (p<0.001), p=0.007, p=0.009, respectively). All PROMs were worse in the AKP group at 10 years (p<0.05). OKSs were worse from 1 year (p<0.05). Multivariate analysis confirmed FCF and Insall ratio <0.8 as independent predictors of AKP (R. 2. = 0.263). Extension of ≥0.5° predicted AKP with 87% sensitivity. AKP affects 25% of patients following single radius cruciate retaining TKA, resulting in inferior patient-reported outcome measures at 10 years. Sagittal plane positioning and alignment of the femoral component are important determinants of long-term AKP with femoral component extension being a major risk factor

Introduction. The authors performed a short term prospective study of unicompartmental knee replacement (UKR) associated to patella-femoral arthroplasty (PFA) for the treatment of bicompartmental symptomatic knee arthritis. At the latest follow-up all the implants were matched to a similar computer assisted Total Knee Replacements (CAS-TKR) group implanted for the same indications. Hypothesis of the study was that this bicompartimental implants could achieve comparable outcomes to TKR with a more conservative surgery and a higher joint function. Materials and Methods. 19 cases of anteriomedial (12) or anterolateral (7) arthritis in 19 stable knees were prospectively involved in the study. All the knees underwent to a selective reconstruction using simultaneously both UKR and PFR using the same surgical technique. All bicompartmental implants were performed by the same surgeon. Surgical time, hospital staying and all intra and post operative complications were registered. At a minimum follow-up of 20 months, every single case was marched to a similar case where had been implanted a computer assisted cruciate retaining TKR. Criteria of matching were: sex, age, pre-operative range of motion and arthritis grade. In both the groups all the cases were assessed clinically using WOMAC, KKS and GIUM scores. All the knees were radiologically investigated using the same radiological protocol. Results. Intra operatively we did not registered any complication. No revision in both groups. The mean surgical time was 86 minutes (range: 78–121) in UKR+PFR group and 81 minutes (range: 71–112) in CAS-TKR group. There were no statistical significant differences in the hospital stay. No statistically significant difference was seen for the Knee Society, Functional and GIUM scores between the 2 groups. Statistically significant better WOMAC Function/Stiffness indexes were registered for the UKR+PFR group. CAS-TKR implants achieved a statistically better aligned mechanical axes. Conclusions. The results of this prospective short term prospective study suggest that UKR+PFR implant is a viable option for bicompartmental anteromedial arthritis at least as well as TKR but maintaining an higher level of function

Radiological evidence of post-traumatic osteoarthritis (PTOA) after fracture of the tibial plateau is common but end-stage arthritis which requires total knee arthroplasty is much rarer.

The aim of this study was to examine the indications for, and outcomes of, total knee arthroplasty after fracture of the tibial plateau and to compare this with an age and gender-matched cohort of TKAs carried out for primary osteoarthritis.

Between 1997 and 2011, 31 consecutive patients (23 women, eight men) with a mean age of 65 years (40 to 89) underwent TKA at a mean of 24 months (2 to 124) after a fracture of the tibial plateau. Of these, 24 had undergone ORIF and seven had been treated non-operatively. Patients were assessed pre-operatively and at 6, 12 and > 60 months using the Short Form-12, Oxford Knee Score and a patient satisfaction score.

Patients with instability or nonunion needed total knee arthroplasty earlier (14 and 13.3 months post-injury) than those with intra-articular malunion (50 months, p < 0.001). Primary cruciate-retaining implants were used in 27 (87%) patients. Complication rates were higher in the PTOA cohort and included wound complications (13% vs 1% p = 0.014) and persistent stiffness (10% vs 0%, p = 0.014). Two (6%) PTOA patients required revision total knee arthroplasty at 57 and 114 months. The mean Oxford knee score was worse pre-operatively in the cohort with primary osteoarthritis (18 vs 30, p < 0.001) but there were no significant differences in post-operative Oxford knee score or patient satisfaction (primary osteoarthritis 86%, PTOA 78%, p = 0.437).

Total knee arthroplasty undertaken after fracture of the tibial plateau has a higher rate of complications than that undertaken for primary osteoarthritis, but patient-reported outcomes and satisfaction are comparable.

Cite this article: Bone Joint J 2015;97-B:532–8.