No radiographic difference between patient-specific guiding and conventional Oxford UKA surgery.
OBJECTIVE
Implant position is an important factor in unicompartmental knee arthroplasty (UKA) surgery. Results on conventional UKA alignment are commonly described in literature. Patient-specific guiding (PSG) is a new technique for positioning the Oxford UKA. Our hypothesis is that PSG improves component position without affecting the HKA angle.


METHODS
This prospective study compares the results of our first thirty cases of cementless Oxford UKA using PSG with thirty cases using conventional outlining. Baseline characteristics for both groups were identical. Details on handling of the guide, estimated blood loss and operation time were recorded. Postoperative screened radiographs and standing long-leg radiographs of both groups were compared.


RESULTS
Median AP position of the femoral component was 3 degrees varus (-5 to 9) using PSG versus 2 degrees varus (-10 to 8) for the conventional group. For the femoral flexion, this was 9 degrees flexion (0-16) using PSG versus 12 degrees flexion (0-20). The tibial median AP position was 1 degree varus (-3 to 7) using PSG versus 2 degrees varus (-5 to 10). The median tibial posterior slope was 5 degrees (1-10) using PSG versus 5 degrees (0-12). All guides aligned well. No conversion to conventional outlining was performed, and no significant changes had to be made to the original approved plan. Operation time, estimated blood loss and postoperative haemoglobin drop were not significantly different between both groups.


CONCLUSIONS
Implant position was not different between both groups, even in the early phase of the learning curve. Perioperative results were not different between both groups.


METHODS
III.
Department of Orthopedic Surgery, AZ Monica, Deurne, Belgium. bartkerens@hotmail.com.
Bart
B
Kerens
Department of Orthopedic Surgery, Orbis Medisch Centrum, Sittard, The Netherlands.
Martijn G M
MGM
Schotanus
Department of Surgery, VieCuri Medical Centre, Venlo, The Netherlands.
Bert
B
Boonen
Department of Orthopedic Surgery, Orbis Medisch Centrum, Sittard, The Netherlands.
Nanne P
NP
Kort
D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007592:Joint Diseases / Q000601:surgery*; D007719:Knee Joint / Q000601:surgery*; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D056888:Patient Positioning / Q000379:methods*; D011446:Prospective Studies; D025321:Surgery, Computer-Assisted / Q000379:methods*