Poor results of the Optetrak™ cemented posterior stabilized knee prosthesis after a mean 25-month follow-up: Analysis of 110 prostheses
ABSTRACT The introduction of a new knee arthroplasty model, even if it differs from a validated implant by only a few details, should be followed by rigorous assessment. The Optetrak™ cemented posterior stabilized knee prosthesis evolved from the Insall prosthesis with a smaller tibial keel associated with a higher tibial cam and increased femorotibial congruency as well as a more posterior-stabilized trochlea.
We hypothesized that this implant with only minor modifications to the Insall prosthesis would provide as favorable results as the Insall prosthesis.
A continuous series of 110 prostheses (106 patients) implanted between 2005 and 2007 was retrospectively analyzed with a mean follow-up of 25 months (range, 12-42 months) by an independent observer. The follow-up was based on the IKS score and the radiological assessment was conducted by three senior surgeons.
The mean IKS score was 83.7 (range, 13-100) points at the last follow-up, the mean function score was 82.6 (range, 30-100 points), and mean flexion was 120° (range, 80-140°). Seventeen patients (15%) were disappointed or dissatisfied, 25 knees (22%) were painful, requiring regular painkillers. The prostheses had a satisfactory mechanical axis, with a mean HKA angle of 177.4 ± 4°, but 25 prostheses (22%) presented rims evolving toward tibial implant loosening, and 24 (21%) developed signs of patellofemoral conflict. With follow-up less than 5 years, nine cases were revised for tibial loosening, three for patellofemoral instability, and one for patellofemoral pain. The cases of tibial loosening were particular because they occurred at the cement-tibial-implant interface. The cumulated survival rate at 36 months was 80.97 ± 9.1% and 76.74 ± 12% at 45 months.
This tibial implant with a small keel does not resist the stresses applied by posterior stabilization, with notably a higher level of stress than the Insall prosthesis from which it was derived. In cases of centering defect, the design of the trochlea can lead to impingement between the edges of the patella and the prominent edges of the prosthetic trochlea. We have suspended implantation of this prosthesis and continue to monitor the progression of patients having received these implants.
Level IV, retrospective study.
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ABSTRACT: We used the Optetrak Condylar Constrained (CCK) implant, a modular and constrained knee implant as replacement for a failed primary arthroplasty, to assess the survivorship, the complications, the clinical, radiological, and functional situation, and the quality of life of those patients in whom a CCK had been implanted in recent years in order to find predictive pre-operative conditions of survival and clinical outcomes. We performed a retrospective study of 125 CCK implanted between 1999 and 2005. The mean follow-up was nine years (range, seven to 13). Mean age was 73.6 years. A total of 78 % of the revised TKA were cemented and 66 % were CR. We assessed the pre-operative, the operative and the postoperative conditions studying the medical files of all the patients. In order to study the functional and clinical situation we used the Hospital for Special Surgery (HSS) score and the Knee Society score (KSS), both clinical and functional. We analysed all the X-rays using the Knee Society Roentgenographic evaluation. The quality of life was studied using the Oxford knee score (OKS). The mean results of the KSS clinical and the KSS functional were 68.24 and 63.85, respectively. There were not any conditions associated with poor results of the knees (p > 0.05). The global survival at 24 months was 92.7 %, at 60 months 87.8 % and at 96 months it was 87.8 %. There were some conditions associated with poor survival of the knees, e.g. patients were younger than 70 years old, rheumatic diseases, kidney faliure, tibial tuberosity osteotomy, PS primary arthroplasty, revision before five years and septic loosening. Based on these results there are some pre-operative factors that change the survival of the total knee replacement revision.International Orthopaedics 01/2014; DOI:10.1007/s00264-013-2268-8 · 2.02 Impact Factor