Mr. Sampath

The Short term follow-up of 127 Uncemented Navigated Total Knee Replacements

Cementless total knee arthroplasty (TKA) implants were designed as an alternative to cemented implants. They were expected to provide long-term fixation without the fear of cement debris particle generation and cement degradation resulting in late prosthetic loosening and failure. They were envisioned as a superior solution for TKA in younger patients. However, critical studies revealed a unique set of complications, which included poor fixation as evidenced by frequent occurrence of radiolucent lines, aseptic loosening, osteolysis, and patellar polyethylene dissociation from metal-backed cementless patellar components. To address some of the issues with cementless implants, porous metal devices have been produced. The porous Plasmapore® titanium coating represents over 20 years of clinical experience, mostly for cementless hip implantation. The purpose of this follow-up investigation is to show the early clinical results of the plasma-sprayed Plasmapore® coating combined with a thin bioactive layer of calcium phosphate, the so-called μ-CaP, in a cementless knee-endoprosthesis. To guarantee good prosthesis alignment and soft tissue balancing all 127 patients in this study were operated using a non-image-based navigation system. These patients, mostly with an indication of idiopathic osteoarthritis, received an  Uncemented primary Total Knee Replacement (TKR) and were reviewed at an average follow-up period between 3 months and 3 years (average: 15 months). For most of the patients the integrated Knee Society Score was available for evaluation of clinical and functional results, and the Oxford Score for a patient self reported outcome. A comparison of preoperative and postoperative rankings showed a significant improvement, from a mean of 79 preoperatively to 184 at 3 months, 188 at 6 months, 191 after 1 year. 8 patients already had 3 year follow-up, with a KSS of 198. The average preoperative Oxford score was 44, after 3 months 17, after 6 months 15. 1 year after operation the assessments revealed an average Oxford score of 15 and after 3 years (for 8 patients) it was 13. There were 25 surgical morbidities. These included bleeding into 2 knees, 2 confirmed superficial wound infections associated with the suture knots, 10 cases of wound erythema, 1 small superficial haematoma, 5 deep vein thromboses with 3 pulmonary embolisms, and 2 cases of Reflex Sympathetic Dystrophy. No prosthesis related problems or revisions occurred.

Shameem A C Sampath 1, South H Voon 2, Howard Davies 2
1The Bluespot Knee Clinic, Blackpool, United Kingdom
2Addenbrookes Hospital, Cambridge, United Kingdom