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Lateral retraction, eversion of patella offer similar outcomes during TKA
During total knee arthroplasty, lateral retraction of the patella did not lead to superior postoperative results compared with eversion of the patella, according to study results.
Researchers randomly assigned 120 patients with degenerative arthrosis to either lateral retraction or eversion during primary total knee arthroplasty (TKA). Primary outcome measures included 1-year, dynamometer-measured quadriceps strength. Secondary outcome measures evaluated during hospital stay included the ability to straight-leg raise, VAS pain scores, walking distance and length of stay, whereas secondary outcome measures evaluated preoperatively and through 1-year follow-up included the SF-36 Physical Component Summary and Mental Component Summary scores, range of motion, quadriceps strength and radiographic rate of patella baja and tilt.
Using a mixed-model analysis of variance, the researchers found no significant differences between the two groups in the 1-year outcome measures. No difference was found in quadriceps strength between the groups at 1-year postoperatively, according to study results. Additionally, although range of motion improved significantly from preoperative values by a mean value of 6°, there was no significant difference between groups.
From preoperatively to 1 year postoperatively, both study groups experienced an improvement in the SF-36 Physical Component Summary score and Mental Component Summary score; however, there were no significant differences between the scores of the two groups. The researchers also found no differences between the groups for the change in frequency of the radiographic patella baja or the radiographic patellar tilt from before surgery to 1 year later.
“We believe that there is a balance between the extent of surgical exposure allowing accurate placement of components and optimal cement fixation and the attempts to preserve the soft-tissue envelope surrounding the knee,” the researchers wrote. “At times, exposure during TKA may be augmented by eversion of the patella, and in our experience, this has not led to inferior postoperative outcomes compared with lateral retraction of the patella.”
Disclosure: Fukunaga is a consultant for New York University’s Department of Athletics, is employed by and received travel accommodations from Lenox Hill Hospital, and received payment from New York University’s Department of Physical Therapy. Ranawat is a consultant for and received payment from DePuy, Mako, ConforMIS and Convatec; has a patent with Mako; and received royalties from Mako and ConforMIS. Rodriguez is a consultant for Smith & Nephew, DePuy, Exactec and Medacta.