The long-term clinical and radiological results of 63 uncemented Low Contact Stress (LCS) total knee replacements in 47 patients with rheumatoid arthritis were reviewed. The average age at the time of surgery was 69 years (53–81). At a mean follow up of 22 years (20–25), 12 patients (17 knees) were alive, 27 (36 knees) had died, and 8 patients (10 knees) were lost to follow-up. Revision was necessary in seven patients (7 knees) (11.1%) at mean 12.1 years following surgery. Four revisions were performed due to meniscal bearing wear, two for collapse of the tibial component, and one for aseptic loosening. Evidence of post-operative infection occurred in two knees (3.2%) within 6 weeks of surgery but resolved with antibiotics. Within the group of deceased patients, five had undergone revision (included in total revisions) but otherwise the primary implant remained in vivo. For all living patients, the mean Oxford Knee Score (/48) was 30.2 (16–41) at latest follow up at mean 19.5 years (15–24.7) following surgery. Mean active flexion was 105 degrees (90–150) at this time point. Our recorded survival rate of the uncemented LCS total knee replacements in patients with rheumatoid arthritis was therefore 88.9% at mean 22 years, or worst-case survival of 73.0% if patients lost to follow-up were considered failures. From a review of the literature and as far as we are aware, this study represents the longest follow up of any uncemented knee arthroplasty performed in a cohort of patients with rheumatoid arthritis

Summary. The 80% porous structure of trabecular metal allows for bone ingrowth in more than 90% of the available surface. The Nexgen LPS Uncemented Knee using a trabecular metal tibial component has performed well at minimum of 5 years’ follow-up. Introduction. Total Knee Arthroplasty prostheses most frequently used in today's practice have cemented components. These have shown excellent clinical results. The fixation can however weaken with time, and cement debris within the articulation can lead to accelerated wear. Cementless implants are less commonly used, but some have also shown good long-term clinical results. The potential advantages of cementless implants are retention of bone stock, less chance of third-body wear due to the absence of cement, shorter operative time, and easier treatment of periprosthetic fractures. The posterior stabilised knee replacement has been said to increase tangential shear stresses on the tibial component and increases contact stresses on the cam and post mechanism hence the great debate of cruciate retaining or cruciate sacrificing implants. Objectives. We report the results of a prospective cohort of consecutive primary total knee arthroplasties using an uncemented posterior stabilised prosthesis using a trabecular metal (tantalum) tibial component at a minimum 5-year follow-up. Methods. Prospective 5 year follow-up of patients undergone an uncemented posterior stabilised total knee replacement using a trabecular metal tibial component (NexgenLPS). Clinical examination, Oxford knee score, Knee society score, SF12 and radiological evaluation undertaken at review. Results. 81 patients, 45 female, 36 male. Left 31, Right 50. Mean age 74.3 yrs range (51–90). SF12, mean: 31.8 range (25–37). Oxford Knee Score Pre-op Mean 20.1 range (9–36) Post op: Mean 32.1 range (9–48). Knee Society score. Pain Mean 91.8; range (60–100). Functional score mean 76.2; range (30–100). Mean Range of movement 110.5 degrees range (90–125). No evidence of loosening at 5 yrs. No deep infection. No Revisions. Conclusion. Although there are a variety of methods of achieving satisfactory initial fixation in cementless components, trabecular metal has an advantage owing to its cellular structure resembling bone. The 80% porous structure of trabecular metal allows for bone ingrowth in more than 90% of the available surface. The Nexgen LPS Uncemented Knee using a trabecular metal tibial component used in this series has shown no evidence of loosening at a minimum of 5 years’ follow-up and the prosthesis as a whole has performed very well clinically. Its early results are comparable to those prostheses most commonly used as reported by the arthroplasty registers. The longer term results from this prosthesis are awaited with interest