Introduction

Total knee arthroplasty (TKA) is the second most common and successful joint replacement in orthopedics. Due to long-term results the problem of aseptic loosening, implant failure and hypersensitivity to metal ions remain. Therefore the introduction of a new TKA with ceramic tibial and femoral components is introduced.

A large number of short stem prosthesis for hip arthroplasty has been introduced in the last years. The main aim of this device is to preserve the proximal bone stock in order to facilitate revisions in the future. Furthermore there is an increase in young and active patients in total hip arthroplasty that's why it's important to consider minimally invasive, muscle-considering procedures. Short stems allow to make minimal invasive approaches easier and improve the biomechanical reconstruction. However, there is a large increase of publication about short stems there is still little data about survival and revision rates. We report about the outcome of 81 patients, who have recieved NANOS short stem prosthesis between October 2012 and April 2014. The average age of the patient was 61,6. The oldest patient was 78 years old and our youngest patient was 41 years old. The main diagnoses were osteoarthritis in 67 patients, dysplastic osteoarthritis in 8 patients and avascular necrosis of the femoral head in 6 patients. We have included 37 female patients and 44 male patients. 3 patients had the surgery on both sides. The average operating time was 75,2 min ± 20,1 min and the average grading of patients for surgical procedures of the American Society of Anesthesiologists was 1,8±0,7. The patients were hospitalized 9,6 days ± 2,9 days. The average BMI was 28,2±5,2. Along with demographic data and co-morbidities, the Harris Hip Score was recorded pre-operatively and at follow-up. The Harris Hip Score increased from 36,6 ± 14,5 pre-operatively to 94,5 ± 8,8 at the final follow-up.

None of the 81 stems were revised this corresponds to a to a survival rate of 100%. Two of the patients suffered from a hip dislocation which was treated in both cases conservative. In further consequence unfortunately one of those patients thrombosed and suffered from a pulmonary embolism. The x-rays haven't shown any radiolucent lines in any patients.

All in all our patients reported about an high post-operative satisfaction. The clinical and radiographic results encouraged us to continue to use short stems with metaphyseal anchorage. However, there must be more long-term results to confirm our excellent mid term results.

Introduction

Presentation of our outcome in implant survival and clinical function using rotating-hinge knee prosthesis in revision total knee arthroplasty.