gms | German Medical Science

Objectives: A customized cruciate retaining TKA implant has been available at our institution since 2012. The objective of this single center study was to prospectively analyze outcomes scores on a series of patients implanted with the second generation of this customized implant using patient specific intruments and implants.

Methods: At our center 73 patients were prospectively recruited and implanted with a customized cruciate retaining total knee replacement. Ethics approval was obtained from our hospital and all patients were consented prior to participating in the study. Inclusion criteria for patients included, intact posterior cruciate and collateral ligaments, a knee deformity which was restricted to <15° varus or valgus and flexion contracture. Patients were assessed for their Knee Society Score, and SF-12 physical and mental scores, preoperatively and yearly thereafter up until a 5 year follow-up time point.

Results: Average age of the patient population was 64yrs (range: 40-81), while the average BMI was 31 (range: 23-42). Average follow-up for outcome scores was 2.1 years and 2.5 years for implant survivorship. The pre-operative baseline values for the Knee Society Knee and Function score was 41 and 53 respectively. At the 2 year follow-up average KSS Knee Scores increased significantly (p<0.001) by 51 points to 92 and stayed at this level until the 5 year time point. KSS Function Scores increased significantly (p<0.001) by 30 points on average to 83 at the 2 year time point with further increases to 86 at the 5 year time point. SF-12 Physical and Mental scores at the pre-operative visit were 28 and 50 respectively. These scores significantly improved (p<0.001) 45 and 53 respectively at the 2 year time point. At the 3 year follow-up visit average SF-12 Physical and Mental scores were 44 and 54 respectively. Patients experienced significant improvements in their knee range of motion at the 2 year visit with further improvements at 3-5 years. Overall range of motion was improved by 16 degrees at 5 years post-operative.

Conclusion: Previous studies conducted on the customized CR TKA have reported patient outcomes at early time points in an American population. This study presents patient outcomes at up to 5 years post-surgery in German patients. Our results corroborate the early results seen with the use of customized CR TKA. We believe, patients with this implant do experience significant benefits within the first year from surgery, which continue into later years. Follow-up at our institution is ongoing, which will shed further light into the long term outcomes for patients with this device.