Abstract
Introduction
A longer operative time will lead to the development of any postoperative complications in total knee arthroplasty (TKA). According to previous reports, a significant increase in TKA procedure time done by novice surgeons was observed compared to high-volume surgeons. Our purpose was to investigate and to clarify the important maneuver necessary for novice surgeons to minimize a surgical time in TKA.
Methods
A total of 300 knees in 248 patients, averaged 74.6 ± 8.7 years, were enrolled. All primary TKAs were done using same instruments (Balanced Knee System®, PS design, Ortho Development, Draper, UT) and same measured resection technique at 14 facilities by 25 orthopedic surgeons. Surgeons were divided into three surgeon groups (4 experts, 9 medium volume surgeons, 12 novices). All methods were approved by our institution's ethics committee.
We divided the operative technique into 5 steps to make comparisons of step-by-step surgical time among surgeon groups of different levels. We defined Phase 1 as performing surgical exposure from skin incision to insertion of the intramedullary rod into the femur. Thereafter, the distal and AP surface of the femur, proximal tibia, the chamfer and PS box of the femur, and patella were resected in Phase 2. In Phase 3, a setup the trial component and a keel of the tibia were done after a confirmation of appropriate ligament balance using the spacer block. Then, a bone surface was irrigated with 2000ml of saline after the removal of the trial component. Subsequently, permanent components were fixed with use of bone cement in Phase 4. Finally, the final irrigation using 2000ml saline and wound closure were done in Phase 5. Every phase of the surgical time was recorded in each TKA.
As a statistical analysis, operation data including length of skin incision, component size, operation time in each phase, and ratio of surgical time in each phase to whole surgical time, were compared using non-repeated measures of ANOVA and a post hoc Bonferroni correction. The threshold for statistical significance was set at a p value of less than 0.05.
Results
A total of 62 TKAs were done by novice surgeons. On the other hand, medium volume surgeons and experts performed 119 and 119 TKAs, respectively.
Gradually, differences among three groups became large phase by phase. Significant differences were detected among groups in each phase (Fig.1). Novice surgeons and medium volume surgeons took much time even in a basic technique including the exposure and wound closure (Fig.2).
Regarding the ratio, no significant differences were detected among groups in Phase 2, 3, and 5. Experts and medium volume surgeons seemed to take caution in fixation of the permanent component. Interestingly, the ratio was still notably different among groups in Phase 1 (Fig.3).
Conclusions
Significant differences among groups were seen in bone resection and implant fixation as well as in a basic technique including exposure and wound closure. Ratio was also notably different among groups in surgical exposure. Therefore, a basic technique would be important to reduce surgical time in novice surgeons in primary TKA.
