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 (R² = 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.

The primary aim of this study was to compare the knee specific functional outcome of partial compared with total knee replacement (TKR) for the management of patellofemoral osteoarthritis.

Fifty-four consecutive Avon patellofemoral replacements were identified and propensity score matched to a group of 54 patients undergoing a TKR with patella resurfacing for patellofemoral osteoarthritis. The Oxford knee score (OKS), the Short Form (SF-) 12 and patient satisfaction were collected (mean follow up 9.2 years). Survival was defined by revision or intention to revise.

There was no significant difference in the OKS (p>0.60) or SF-12 (p>0.28) between the groups. The TKR group was significantly less likely to be satisfied with their knee (95.1% versus 78.3%, OR 0.18, p=0.03). Length of stay was significantly (p=0.008) shorter for the Avon group (difference 1.8 days, 95% CI 0.4 to 3.2). The 10 year survival for the Avon group was 92.3% (95% CI 87.1 to 97.5) and for the TKR group was 100% (95% CI 93.8 to 100). There was no statistical difference in the survival rate (Log Rank p=0.10).

The Avon patellofemoral replacement have a shorter length of stay with a functional outcome and satisfaction rate that is equal to that of TKR. The benefits of the Avon need to be balanced against the increased rate of revision when compared with TKR.

The Low Contact Stress (LCS) mobile-bearing total knee replacement (TKR) was designed to minimize polyethylene wear, aseptic loosening and osteolysis. However, registry data suggests there is a significantly greater revision rate associated with the LCS TKR.

The primary aim of this study was to assess long-term survivorship of the LCS implant. Secondary aims were to assess survival according to mechanism of failure and identify predictors of revision.

We retrospectively identified 1091 LCS TKRs that were performed between 1993 and 2006. There was incomplete data available 33 who were excluded. The mean age of the cohort was 69 (SD 9.2) years and there were 577 TKRs performed in females and 481 in males. Mean follow up was 14 years (SD 4.3).

There were 59 revisions during the study period: 14 for infection, 18 for instability, and 27 for polyethylene wear. 392 patients died during follow up. All cause survival at 10-year was 95% (95%CI 91.7–98.3) and at 15-year was 93% (95%CI 88.6–97.8). Survival at 10-years according to mechanism of failure was: infection 99% (95%CI 94–100%), instability 98% (95%CI 94–100%), and polyethylene wear 98% (95%CI92–100). Of the 27 with polyethylene wear only 19 had associated osteolysis requiring component revision, the other 8 had simple polyethylene exchanges. Cox regression analysis, adjusting for confounding variables, identified younger age was the only predictor of revision (hazard ratio 0.96, 95%CI 0.94–0.99, p=0.003).

The LCS TKR demonstrates excellent long-term survivorship with a low rate of revision for osteolysis, however the risk is increased in younger patients.

This study assessed whether patient satisfaction with their hospital stay influences the early outcome of total knee replacement (TKR).

During a five year period patients undergoing primary TKR at the study centre had prospectively outcome data recorded (n=2264). Patients with depression (p=0.04) and worse mental wellbeing (p<0.001), according to the short form (SF)-12, were more likely to be dissatisfied with their hospital stay. Decreasing level of satisfaction with their hospital stay was associated with a significantly worse post-operative OKS (p<0.001) and SF-12 score (p<0.001). Multivariable regression analysis confirmed that the patients perceived level of satisfaction with their hospital stay was an independent predictor of change in the OKS (p<0.001) and SF-12 score (p<0.001) after adjusting for confounding variables. Patient satisfaction with their TKR was significantly influenced by their hospital experience, decreasing from 96% in those with an excellent experience to 42% in those with a poor experience. Food, staff/care, and the hospital environment were the most frequent reasons of why patients rated their hospital experience as fair or poor.

A patient's perception of their inpatient hospital experience after surgery is an important modifiable predictor of early functional outcome and satisfaction with TKR.

There is conflicting data from small retrospective studies as to whether pre-operative mental health influences the outcome of total knee replacement (TKR).

We assessed the effect of mental disability upon the outcome of TKR and whether mental health improves post-operatively. During a three year period patients undergoing TKR for primary osteoarthritis at the study centre had prospectively outcome data recorded (n=962). Pre-operative and one year short-form (SF) 12 scores and Oxford knee scores (OKS) were obtained. The mental component of the SF-12 was stratified into four groups according to level of mental disability (none ≥50, mild 40to49, moderate 30to39, severe <30). Ethical approval was obtained (11/AL/0079).

Patients with any degree of mental disability had a significantly greater subjective physical disability according to the SF-12 (p=0.06) and OKS (p<0.001). Although the improvement in the disease specific score (OKS) was not affected by a patients mental health (p=0.33). In contrast the improvement of the global physical health (SF-12) for patients with a mental disability did not improve to the same magnitude (p<0.001). However, patients with mental disability, of any degree, had a significant improvement in their mental health post-operatively (p<0.0001). Despite the similar improvement in the disease specific scores and improvement in their mental health, patients with mental disability were significantly more likely to be dissatisfied with their TKR at one year (p=0.001).

TKR for patients with poor mental health benefit from improvement in their mental health and in their knee function, but do have a higher rate of dissatisfaction.