Preliminary results of a new surgical technique in total knee arthroplasty (TKA) using the native ligament tension for femoral implant positioning in varus osteoarthritis.
OBJECTIVE
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.


CONCLUSIONS
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.


METHODS
Therapeutic study level IV.
Clinic of Orthopaedics, Sports Medicine and Rehabilitation, Krankenhaus Märkisch-Oderland GmbH, BT Wriezen, Wriezen, Germany.
Hagen
H
Hommel
Orthopaedic Department, Center for Musculoskeletal Surgery, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany.
Carsten
C
Perka
Orthopaedic Department, Center for Musculoskeletal Surgery, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany. tilman.pfitzner@charite.de.
Tilman
T
Pfitzner
D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D005260:Female; D005269:Femur / Q000601:surgery; D006801:Humans; D007595:Joint Prosthesis; D007719:Knee Joint / Q000601:surgery*; D008023:Ligaments, Articular / Q000601:surgery; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery*; D056888:Patient Positioning; D011184:Postoperative Period; D011446:Prospective Studies; D016059:Range of Motion, Articular / Q000502:physiology
Functional leg axis; Gap balancing; Patient-specific instruments; Total knee arthroplasty