DOS BULLETIN - Dansk Ortopædisk Selskab

2010-378_DOS nr. 3 2010 29/09/10 10:08 Side 135
Can “high flex” be achieved and does it matter in
total knee arthroplasty?
A randomized, controlled trial
Morten Grove Thomsen, Henrik Husted, Kristian Otte, Anders Troelsen
Dept. of Orthopedics, University Hospital of Hvidovre, Denmark
Background: Pain free range of motion (ROM) is a cornerstone in successful
total knee arthroplasty (TKA). The achievement of a high degree
of knee flexion is thought to improve the activity in daily living and possibly
the patient satisfaction.
Purpose: The purpose was to compare ROM, patient satisfaction, pain,
“feel” of the knee, and activities of daily living between a standard posterior
cruciate- retaining TKA and a “high flex” posterior-stabilized
TKA.
Methods: The study is a randomized, single-blinded, controlled trial in
which patients undergoing one-stage bilateral TKA randomly had a standard
AGC (Biomet®) cruciate-retaining TKA in one knee and a Highflex
LPS (Zimmer®) posterior-stabilized TKA in the contra lateral knee.
At follow-up 6 weeks, 3, 6 and 12 months postoperatively, the ROM, satisfaction,
pain, “feel” of the knee, and the abilities in daily activities
were assessed. The study group consisted of 33 patients (mean age: 67.2
yrs). The knees had comparable preoperative ROM.
Findings: At 1-year follow-up we found a significantly higher degree of
knee flexion of 7°, both active and passive, in the “high-flex” group (p=
0.001). The “high-flex” LPS TKA showed a mean active flexion of 121°
(range: 105°-140°) and passive flexion of 127° (range: 107°-146°). In
both groups the median VAS pain score was 0, the median VAS satisfaction
score was 9, and the median VAS score of the patient “feel” of
the knee was 9 at 1-year follow-up. Further, there were no significant
differences between the groups in the performance of daily activities.
Conclusion: The “high-flex” TKA showed increased knee flexion, but
no significant differences in patient related outcomes were found. This
suggests little clinical relevance of the difference in knee flexion as pain
free ROM and high patient satisfaction were achieved with both TKA’s.
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