Hagen Hommel1, Carsten Perka2, Tilman Pfitzner3. 1. Clinic of Orthopaedics, Sports Medicine and Rehabilitation, Krankenhaus Märkisch-Oderland GmbH, BT Wriezen, Wriezen, Germany. 2. Orthopaedic Department, Center for Musculoskeletal Surgery, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany. 3. Orthopaedic Department, Center for Musculoskeletal Surgery, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany. tilman.pfitzner@charite.de.
Abstract
PURPOSE: Individual implant alignment in total knee arthroplasty (TKA) has seen growing interest over the past years. This study therefore aimed to develop a surgical technique for implant alignment based on native ligament tension, and to present the results obtained using this technique. METHODS: 25 patients were included in this prospective study. Patient-specific instrumentation (PSI) was used for the resection of the extension gap. Ligament tension was measured after the removal of all accessible osteophytes. In the event of asymmetry, the distal femur resection was adjusted up to 2.5° using an adjustable cutting block. The aim was to achieve a symmetrical extension gap without release, not a neutral leg axis. Femoral rotation was aligned on the basis of ligament tension. Patients were followed up to 3 months postoperatively. RESULTS: The postoperative whole-leg axis was 2.8° ± 1.6° varus. Patients achieved a flexion of 118° ± 9°, a Knee Score of 91.5 ± 3.2 and a Function Score of 86.8 ± 8.3 points. CONCLUSION: For the first time, the new surgical technique described here permits a ligament tension based femoral implant alignment together with PSI. It was shown to be safe, with encouraging clinical and radiological results. LEVEL OF EVIDENCE: Therapeutic study level IV.
PURPOSE: Individual implant alignment in total knee arthroplasty (TKA) has seen growing interest over the past years. This study therefore aimed to develop a surgical technique for implant alignment based on native ligament tension, and to present the results obtained using this technique. METHODS: 25 patients were included in this prospective study. Patient-specific instrumentation (PSI) was used for the resection of the extension gap. Ligament tension was measured after the removal of all accessible osteophytes. In the event of asymmetry, the distal femur resection was adjusted up to 2.5° using an adjustable cutting block. The aim was to achieve a symmetrical extension gap without release, not a neutral leg axis. Femoral rotation was aligned on the basis of ligament tension. Patients were followed up to 3 months postoperatively. RESULTS: The postoperative whole-leg axis was 2.8° ± 1.6° varus. Patients achieved a flexion of 118° ± 9°, a Knee Score of 91.5 ± 3.2 and a Function Score of 86.8 ± 8.3 points. CONCLUSION: For the first time, the new surgical technique described here permits a ligament tension based femoral implant alignment together with PSI. It was shown to be safe, with encouraging clinical and radiological results. LEVEL OF EVIDENCE: Therapeutic study level IV.
Entities:
Keywords:
Functional leg axis; Gap balancing; Patient-specific instruments; Total knee arthroplasty
Authors: Philippe Moewis; Hagen Hommel; Adam Trepczynski; Leonie Krahl; Philipp von Roth; Georg N Duda Journal: Sci Rep Date: 2019-06-24 Impact factor: 4.379