Posterior cruciate-substituting total knee replacement recovers the flexion arc faster in the early postoperative period in knees with high varus deformity: a prospective randomized study.
BACKGROUND
Posterior cruciate retention (CR) and substitution (PS) has been controversial in knee replacement surgery. Satisfactory medium and long-term results have been reported in knees with and without deformity but there are limited studies about early functional comparison in terms of recovery of flexion arc, stair activity, walking ability and straight leg raising, especially, in early postoperative period in knees with deformity. Therefore, we aimed to compare the flexion arc in CR and PS knees in postoperative first year including early postoperative days prospectively.


METHODS
Consecutive patients with a deformity of >10° were included and allocated to CR and PS groups randomly. KSS and Feller-patella scores were recorded both preoperatively and postoperatively (1st, 2nd, 3rd and 12th months). Flexion and extension were measured both preoperatively and postoperatively (1st, 2nd, 3rd day and discharge day as well as 1st, 2nd, 3rd and 12th months). Visual analog scale (VAS) was recorded postoperatively at the 1st, 2nd, 3rd and discharge day and at 1st, 2nd, 3rd and 12th months. The walking ability, stair activity and straight leg raising were recorded. Patients were also examined at the last visit with minimum 7-year follow-up with KSS, Feller-patella and VAS scores. Their mean flexion arcs were measured and recorded.


RESULTS
There were 61 TKR evaluated. KSS knee and function scores at the 3rd month and KSS Knee Score at 1st year were superior in PS knees (p = 0.029, p = 0.046, p = 0.026). Flexion arc was found larger on day 1, 2, 3 and discharge day, and at 1st, 2nd, 3rd and 12th month in PS group (p = 0.048, p = 0.002, p = 0.027, p = 0.043, p = 0.014, p = 0.003, p = 0.002, p = 0.018). Walking and stair activity showed no difference but straight leg raising was better in CR knees (p = 0.02). Mean flexion arc was larger in PS knees at the last visit after 7 years (119.0° ± 7.5° in PS and 113.8° ± 8.7° in CR, p = 0.02). There was no revision required in that time interval. The other parameters were similar between groups.


CONCLUSIONS
PS knees gained active flexion arc faster and larger. But straight leg raising activity recovered early in CR knees. Both types of prosthesis produced satisfactory outcome. PS and CR TKRs can be performed with the same performance in osteoarthritic knees even with high varus deformity.


METHODS
Prospective Randomized Controlled Trial, Level II.
Clinic of Orthopaedics and Traumatology, Bursa Yuksek Ihtisas Research and Training Hospital, Yıldırım, Bursa, Turkey. ozturkalp16@gmail.com.
Alpaslan
A
Öztürk
Clinic of Orthopaedics and Traumatology, Bursa Yuksek Ihtisas Research and Training Hospital, Yıldırım, Bursa, Turkey.
Yavuz
Y
Akalın
Clinic of Orthopaedics and Traumatology, Bursa Yuksek Ihtisas Research and Training Hospital, Yıldırım, Bursa, Turkey.
Nazan
N
Çevik
Clinic of Orthopaedics and Traumatology, Bursa Yuksek Ihtisas Research and Training Hospital, Yıldırım, Bursa, Turkey.
Ali
A
Otuzbir
Clinic of Orthopaedics and Traumatology, Bursa Yuksek Ihtisas Research and Training Hospital, Yıldırım, Bursa, Turkey.
Yüksel
Y
Özkan
Clinic of Orthopaedics and Traumatology, Turkish Ministry of Health İznik State Hospital, Iznik, Bursa, Turkey.
Yasin
Y
Dostabakan
D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology / Q000601:surgery*; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery*; D010147:Pain Measurement; D016119:Posterior Cruciate Ligament / Q000601:surgery*; D011184:Postoperative Period; D011446:Prospective Studies; D016059:Range of Motion, Articular / Q000502:physiology
Cruciate-retaining; Flexion arc; Knee; Knee flexion; Posterior stabilized; Prospective; Range of motion; Straight leg raising; Total knee replacement