Abstract
Introduction
The purpose of this study is to evaluate the mid-term results of clinical and radiographic results Hi-tech knee a cementless total knee arthroplasty (Nakashima medical Co. Ltd., Okayama, Japan). This TKA system was developed in Chiba University from 1994. The characteristic of this system are flat on flat CR-TKA and cementless fixation. Contact surface are made of titanium alloy and UHMWPE, which is produced by the direct compression mold manufacturing method.
Material and Method
Between May 1998 and May 2005, we performed 53 consecutive primary TKAs for 42 patients. There were 41 women and 1 man with a mean age of 64.4 years (39 to 78 years). The average follow up period was 7 years 8 months (5 years to 12 years). Osteoarthritis knee were 21 knees and rheumatoid arthritis were 32 knees. The mean pre-operative FTA was 181.7 degrees (168 to 203 degrees). The method of the operation went in measured cut technique for all cases. All 53 knees were implanted with a cruciate retaining prosthesis. All comportments, included a patella component, were fixed without cement. Clinical evaluations were performed according to American Knee Society (KS) system, knee score and function score.
Results
The mean preoperative and postoperative, at the latest follow up, maximum flexion angles were 104 and 114 degrees, respectively. The KS knee score and function score improved from 47.5 and 38.9 points before surgery to 87.6 and 80.4 points after surgery, respectively. Postoperative alignment FTA average 174.8 degrees. Within follow up period, it maintained good valgus-varus stability. There was no major loosening. Six knees (11%) were observed radiolucent line at medial tibia plateau less than 1mm. No revisions of TKA were required because of loosening or sinking. There was also no problem at patellar component.
Conclusions
Hi-Tech knee a cementless TKA system was made for the suitable for a Japanese knee, strong initial fixation in a concept. The patella component is also cementless fixation. Contact surface are made of titanium alloy and UHMWPE of the direct compression mold method, it was able to protect the abrasion of the polyethylene in a stable state, too. The mid-term results of Hi-Tech knee a cementless TKA, not only OA but also RA patient knee, provided almost good results.
