Time-dependent improvement in functional outcome following LCS rotating platform knee replacement.
OBJECTIVE
Long-term follow-up studies after total knee replacement (TKR) using an LCS rotating platform have shown survival rates of up to 97%. Few studies have evaluated short-term functional outcome and its improvement over time. We determined the time course of functional outcome as evaluated by the knee injury and osteoarthritis outcome score (KOOS) over the first 4 years after TKR using the LCS mobile bearing.


METHODS
50 unselected patients (mean age 70 (40-85) years, 33 women) with osteoarthritis in one knee underwent TKR with an LCS mobile bearing. Data were collected by an independent investigator preoperatively and at 6 weeks, 3 months, 6 months, 1 year, 2 years and 4 years postoperatively. KOOS, a self-assessment function score validated for this purpose, and range of motion (ROM) were determined at all follow-ups.


RESULTS
The mean KOOS pain score increased from 43 before surgery to 66 at 6 weeks and 88 at 2 years. It was 84 at 4 years. The mean KOOS activities of daily living score (ADL) increased from 49 before surgery to 73 at 6 weeks, then gradually to 90 at 2 years. It decreased to 79 at 4 years. Mean passive ROM was 112° before surgery, 78° at departure from hospital, and then gradually increased to 116° at 2 years and 113° at 4 years.


CONCLUSIONS
Recovery after TKR is time-dependent. Most of the expected improvement in pain and function is achieved at 6 months postoperatively, but some further improvement can be expected up to 2 years postoperatively. ROM will also gradually improve up to 2 years after TKR, and reach the same level as before surgery.
Martina Hansens Hospital, Baerum, Norway. kjetil@legesiden.no
Tor Kjetil
TK
Nerhus
Stig
S
Heir
Elisabeth
E
Thornes
Jan Erik
JE
Madsen
Arne
A
Ekeland
D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000379:methods; D001843:Bone Cements; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007718:Knee Injuries / Q000601:surgery; D007720:Knee Prosthesis; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery; D011446:Prospective Studies; D011474:Prosthesis Design; D016059:Range of Motion, Articular; D020127:Recovery of Function; D012399:Rotation; D013314:Stress, Mechanical; D013997:Time Factors; D016896:Treatment Outcome
D001843:Bone Cements