Isolated revision of the polyethylene component at revision total knee arthroplasty has excellent survivorship at ten years.

AIMS: The aim of this study was to establish the results of isolated exchange of the tibial polyethylene insert in revision total knee arthroplasty (RTKA) in patients with well-fixed femoral or tibial components. We report on a series of RTKAs where only the polyethylene was replaced, and the patients were followed for a mean of 13.2 years (10.0 to 19.1). PATIENTS AND METHODS: Our study group consisted of 64 non-infected, grossly stable TKA patients revised over an eight-year period (1998 to 2006). The mean age of the patients at time of revision was 72.2 years (48 to 88). There were 36 females (56%) and 28 males (44%) in the cohort. All patients had received the same cemented, cruciate-retaining patella resurfaced primary TKA. All subsequently underwent an isolated polyethylene insert exchange. The mean time from the primary TKA to RTKA was 9.1 years (2.2 to 16.1). RESULTS: At final follow-up, 13 patients had died, leaving 51 patients for study. Only seven of these patients had required re-operation. Knee Society scores (KSS) prior to RTKA were a mean of 78.4 (24 to 100). By six weeks post-revision, the mean total KSS was 93.5 (38 to 100) and at final follow-up, they had a mean of 91.6 (36 to 100). CONCLUSION: In appropriate circumstances, where the femoral and tibial components are satisfactorily aligned and well fixed, and where the soft tissues can be balanced, a polyethylene exchange alone can provide a durable solution for these RTKA patients. Cite this article: Bone Joint J 2019;101-B(7 Supple C):104-107.

The association of pre-operative body pain diagram scores with pain outcomes following total knee arthroplasty.

OBJECTIVE: Approximately 20% of total knee arthroplasty (TKA) recipients have suboptimal pain relief. We evaluated the association between pre-surgical widespread body pain and incomplete pain relief following TKA. METHOD: This prospective analysis included 241 patients with knee osteoarthritis (OA) undergoing unilateral TKA who completed questionnaires preoperatively and up to 12 months post-operatively. Questionnaires included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain scale and a body pain diagram. We derived the number of non-index painful body regions from the diagram. We used Poisson regression to determine the association between painful body regions identified preoperatively and both WOMAC pain at follow-up and improvement in pain as defined by the minimal clinically important difference (MCID). RESULTS: Mean subject age was 66 years (SD 9), and 61% were females. Adjusting for age, sex, co-morbid conditions, baseline pain, pain catastrophizing, and mental health, we found that more widespread body pain was associated with a higher likelihood of reporting 12-month WOMAC pain score >15 (relative risk [RR] per painful body region 1.39, 95% CI 1.18-1.63) and a greater likelihood of failing to achieve the MCID (RR 1.47, 95% CI 1.16-1.86).). Pain catastrophizing was an independent predictor of persistent pain and failure to improve by the MCID (RR 3.57, 95% CI 1.73-7.31). CONCLUSIONS: Pre-operative widespread pain was associated with greater pain at 12-months and failure to reach the MCID. Widespread pain as captured by the pain diagram, along with the pain catastrophizing score, may help identify persons with suboptimal TKA outcome.

Cementless total knee arthroplasty: current concepts review.

As the number of younger and more active patients treated with total knee arthroplasty (TKA) continues to increase, consideration of better fixation as a means of improving implant longevity is required. Cemented TKA remains the reference standard with the largest body of evidence and the longest follow-up to support its use. However, cementless TKA, may offer the opportunity of a more bone-sparing procedure with long lasting biological fixation to the bone. We undertook a review of the literature examining advances of cementless TKA and the reported results. Cite this article: Bone Joint J 2016;98-B:867-73.

Analysis of the outcome in male and female patients using a unisex total knee replacement system.

Gender-specific total knee replacement has generated much interest recently. We reviewed 1970 Sigma knees implanted in 920 women and 592 men with a mean age of 69.7 years. At a mean follow-up of 7.3 years (minimum, five years), we found minimal differences in the outcome between genders. At the final follow-up, men had a higher overall Knee Society score and more osteolysis (3.8% vs 1.1%). However, there were no significant differences between men and women in terms of complications or improvements in knee function, pain score or range of movement. The estimated ten-year survivorship was 97% in women and 98% in men (p = 0.96). We concluded that there was little difference in outcome between the genders treated by a modern unisex design of total knee replacement in this large multicentre study.

Midterm survival of a contemporary modular total knee replacement: a multicentre study of 1970 knees.

This retrospective study evaluated the midterm clinical and radiographic outcomes of a second-generation total knee replacement system. In a multicentre consecutive series of 1512 patients, 1970 knees were treated with the PFC Sigma knee system (Depuy, Warsaw, Indiana). The patients were reviewed for functional outcome, and underwent independent radiographic evaluation at a mean follow-up of 7.3 years (5 to 10). A total of 40 knees (2%) required revision, 17 (0.9%) for infection. The incidence of osteolysis was 2.2%. The ten-year survival with revision for any cause other than infection as the endpoint was 97.2% (95% CI 95.4 to 99.1). The PFC Sigma knee system appears to provide excellent results in the medium term.

Observations of the proximal tibia in total knee arthroplasty.

Relatively little has been written concerning the proximal tibia in total knee arthroplasty. Few authors have looked at landmarks and guidelines for tibial tray preparation and tibial tray orientation. The current study showed that a line drawn 1 mm medial to the medial border of the tibial tubercle and going through the midsulcus of the tibial spines (the midsulcus line) provided a reproducible landmark for the tibia, and when a perpendicular cut was made relative to this line, 46 of 50 knees were cut in appropriate alignment. In addition, it has been said that the tibial tray should be rotated externally to approximately the medial 1/3 of the tubercle to maximize function. The current study showed that when the tibia is allowed to float in a functional position relative to the femoral implant, the tibial external rotation was only 2 mm lateral from the medial age of the tibial tubercle; this is far less than the medial 1/3 of the tubercle and close to the starting point of the midsulcus line.

A comparison of the midvastus and paramedian approaches for total knee arthroplasty.

This prospective, double-blinded evaluation of 24 osteoarthritic patients undergoing bilateral total knee replacement compared the midvastus and standard parapatellar approaches. The midvastus approach was found to offer an early advantage in terms of less pain and earlier return to function. There were no significant complications associated with the midvastus approach. This approach should be a part of the knee surgeon's armamentarium.

Total knee arthroplasty in a group of patients less than 45 years of age.

The long-term follow-up evaluation of total knee arthroplasty (TKA) in patients under age 45 is reviewed. One hundred three knees in 67 patients who had an average follow-up period of 7.2 years were retrospectively reviewed. Fifty-eight percent of the patients had rheumatoid arthritis, and 29% had juvenile rheumatoid arthritis. Thirteen percent of the patients had post-traumatic arthritis, avascular necrosis, hemochromatosis, or lupus. The results demonstrate that the success of TKA in this patient population are comparable to those for TKA in the elderly.