Unicompartmental knee arthroplasty replaces only the damaged compartments. Since it is performed earlier, before secondary involvement of other structures in the knee better results colud reasonably be expected. The advantages of unicompartmental
knee
arthroplasty, as opposed to total knee arthroplasty, lie in more normal walking pattern and preservation of proprioception.
Between Dec. 1982 and Dec. 1991 48 unicompartmental prostheses were implanted in 35 patients at the department of orthlopaedic surgery, Kyung Hee University.
The average follow-up period was one year nine months. Functional assessments including rating by the Hospital for Special Surgery Knee Score and radiographic evaluation, were conducted.
1. Modular II unicompartmental knee arthroplasty were implanted in 14 cases inset method, Microloc unicompartmental knee arthroplasty were implanted in 34 cases with L-cut method.
2. The average age at operation was 62.2 years (56 ~ 76 years) in Mod II type, 61.2 years (45 ~ 81 years) in Microloc type.
3. The preoperative diagnosis was osteoarthritis in 10 patients in Mod II type, osteoarthritis in 22 patients and osteonecrosis in 3 patients in Microloc type. 12 knees had undergone medial compartmental arthroplasty and 2 knees had undergone
lateral
compartmental arthroplasty among Mod II type. All cases with Microloc type had undergone medial compartmental arthyroplasty.
4. The average preoperative range of motion was 121.8°and the average postoperative range of motion was 124.2°in Mod II type, the average preoperative range of motion was 122.3°and the average postoperative range of motion was 130°in
Microloc
type.
5. The average tibiofemoral angle was corrected from valgus 1.7°preoperatively to valgus 4.5°postoperatively in Mod II type, from varus 1.6°to valgus 4.5°postoperatively in Microloc type.
6. The final average Prosthe3sis Tibia Angle was 86.6°in Mod II type, 88.9°in Microloc type.
With using guide, Prosthesis Tibia Angle was more near to 90°in Microloc group.
7. the Tibia Posterior Slope Angle was 7.2°in Mod II group and 4.3°in Microloc group.
The Tibia Posterior Slope Angle was more anatomical in Mod II group.
8. The average preoperative Hospital for Special surgery Knee Rating Score was 45.7 points and postoperatively the average score improved to 86.6 points in Mod II group the preoperative knee rating score was 47.7 points and postoperativgely the
average
score improved to 93.6 points in Micrologc group.
9. Although Prosthesis Tibia angle and Tibia Posteror Slope angle was more anatomical in Mod II group the average knee score was higher in Microloc group than Mod II group.
10. the knee rating score had no relation with Prosthesis Tibia angle or Tibia Posterior Slope angle. (if the ptrosthesis Tibia Angle or Tibia Posterior slope angle was in the range of reltively near to moral angles).
11. With using instrument guide, L-cut method was reproducible to the same cutting angle.
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