Three- to six-year follow-up results after high-flexion total knee arthroplasty: can we allow passive deep knee bending?
OBJECTIVE
We evaluated 3- to 6-year clinical and radiological follow-up results after NexGen® LPS-flex total knee arthroplasty (TKA).


METHODS
A retrospective evaluation was undertaken of 218 knees in 166 patients (22 males, 144 females) who were followed up for more than 3 years after TKA. Evaluations included preoperative and postoperative range of motion (ROM) measurement, Knee Society (KS) Score, tibiofemoral angle and assessment of postoperative complications.


RESULTS
TKA resulted in a significant ROM increase from a mean flexion contracture of 9° (range 0°-20°) and further flexion of 117° (range 80°-155°) to a mean flexion contracture of 2° (range 0°-10°) and a further flexion of 131° (range 95°-155°). KS knee and function scores significantly improved from 52 and 38 before surgery to 87 and 82 after surgery, respectively. The tibiofemoral angle significantly improved from varus 5.7° to valgus 5.4°. Progressive radiolucent lines around the femoral component on radiographs were observed in 30 knees (13.8%, 27 patients), and more of those knees, could squat than non-radiolucent knees (76.7 vs. 20.2%; P<0.05). Seven knees (3.2%, 6 patients) were revised at a mean 49 months after the index operation.


CONCLUSIONS
While NexGen® LPS-flex TKA satisfactorily improved ROM, it was associated with a relatively high incidence of early loosening of the femoral components. This might be associated with passive-maximal flexion activity, such as squatting or kneeling. The clinical relevance of this study is that squatting or kneeling, common activity in Asian, may not be allowed after NexGen® LPS-flex TKA.
Cho
Sung-Do
SD
Department of Orthopedic Surgery, Ulsan University Hospital, Ulsan University College of Medicine, 290-3 Jeonha-dong, Dong-gu, Ulsan, 682-714, Korea. sdcho@uuh.ulsan.kr
Youm
Yoon-Seok
YS
Park
Ki-Bong
KB
D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000379:methods* / Q000534:rehabilitation; D015331:Cohort Studies; D015444:Exercise; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007593:Joint Instability / Q000517:prevention & control; D007719:Knee Joint / Q000503:physiopathology*; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000601:surgery; D010147:Pain Measurement; D017060:Patient Satisfaction / Q000706:statistics & numerical data; D010808:Physical Examination / Q000379:methods; D011182:Postoperative Care / Q000379:methods; D016059:Range of Motion, Articular / Q000502:physiology*; D020127:Recovery of Function; D012189:Retrospective Studies; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome; D016474:Weight-Bearing / Q000502:physiology*