Influence of stability on range of motion after cruciate-retaining TKA.
BACKGROUND
A loosely balanced total knee arthroplasty (TKA) is reported to produce a good postoperative range of motion (ROM), but too much laxity is thought to be the cause of persistent pain and worsened functionality.


METHODS
The anteroposterior and mediolateral laxity values were measured to evaluate the influence of stability after cruciate-retaining (CR) TKA on ROM and the modified Knee Society score at 4-8 years after the operation. Twenty-one knees in 15 patients with an average age of 68 years who had undergone a CR TKA for osteoarthrosis were examined. The mean preoperative and postoperative ROM was 124 degrees and 112 degrees, respectively. The mean anteroposterior and mediolateral laxity values were 9.7 mm and 10.6 degrees, respectively.


RESULTS
No correlation was found between the postoperative ROM and laxity or between the modified Knee Society score and laxity. A loosely balanced TKA did not produce a good postoperative ROM. No parameters suggested that lax knees showed a higher pain score and lower functional score than stable knees.
Yamakado
Kotaro
K
Department of Orthopaedic Surgery, School of Medicine, Kanazawa University, 13-1, Takara-machi, Kanazawa, 920-8641, Japan. yamakado@nsknet.or.jp
Kitaoka
Katsuhiko
K
Yamada
Hiroshi
H
Hashiba
Kensaku
K
Nakamura
Ryuichi
R
Tomita
Katsuro
K
D000368:Aged; D016118:Anterior Cruciate Ligament / Q000502:physiology*; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects / Q000379:methods*; D015331:Cohort Studies; D005069:Evaluation Studies as Topic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007593:Joint Instability; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D020370:Osteoarthritis, Knee / Q000175:diagnosis / Q000601:surgery*; D010147:Pain Measurement; D011336:Probability; D016059:Range of Motion, Articular / Q000502:physiology*; D020127:Recovery of Function; D012044:Regression Analysis; D013997:Time Factors; D016896:Treatment Outcome