Soininvaara Tarja A, Harju Kristiina A L, Miettinen Hannu J A, Kröger Heikki P J
North Karelia Central Hospital, Joensuu Finland.
Knee. 2013 Mar;20(2):120-7. doi: 10.1016/j.knee.2012.10.004. Epub 2012 Nov 13.
Unicompartmental knee arthroplasty (UKA) has received renewed interest in the last decade. UKA involves minor injury to soft tissues, limited removal of bone and delicate preservation of knee anatomy and geometry. In theory, UKA provides an opportunity to restore post-surgical knee kinematics to near normal.
UKA leaves patellofemoral joint free to meet high mechanical forces with no stress-shielding and therefore might preserve bone mineral density (BMD).
We studied 21 patients with osteoarthritis (OA), who had received medial compartment UKA at Kuopio University Hospital between October 1997 and September 2000. BMD was measured by dual-energy X-ray absorptiometry (DEXA), at baseline (within a week after surgery) and at intervals until 7 years.
DEXA results were reproducible. The highest rate of periprosthetic bone loss occurred during the first 3 months after UKA. The average loss in BMD was 4.4% (p = 0.039) in the femoral diaphysis and it ranged from 11.2% (p < 0.001) to 11.9% (p = 0.002) in the distal femoral metaphysis; however, BMD changes in these regions, from 2 years to 7 years, were nonsignificant. At the 1-year follow-up, the BMD of the medial tibial metaphysis had increased by 8.9% (p = 0.02), whereas those in the lateral tibial metaphysial (-2.4%) and diaphysial regions (-2.0%) did not change significantly.
UKA did not preserve periprosthetic BMD in the distal femoral metaphysis, whereas BMD changes in the tibial metaphysis were minor, consistent with a mechanical balance between the medial and lateral tibial compartments. LEVEL OF EVIDENCE 2B: Prospective case control study.
单髁膝关节置换术（UKA）在过去十年中重新受到关注。UKA对软组织损伤较小，骨切除有限，能精细地保留膝关节的解剖结构和几何形态。理论上，UKA为将术后膝关节运动学恢复至接近正常水平提供了契机。
UKA使髌股关节能够承受高机械力且无应力遮挡，因此可能保留骨矿物质密度（BMD）。
我们研究了21例骨关节炎（OA）患者，这些患者于1997年10月至2000年9月在库奥皮奥大学医院接受了内侧单髁膝关节置换术。通过双能X线吸收法（DEXA）在基线期（术后一周内）及之后每隔一段时间直至7年测量骨密度。
DEXA结果具有可重复性。假体周围骨量丢失率最高发生在UKA后的前3个月。股骨干的骨密度平均丢失4.4%（p = 0.039），股骨远端干骺端的骨密度丢失率在11.2%（p < 0.001）至11.9%（p = 0.002）之间；然而，这些区域从2年到7年的骨密度变化不显著。在1年随访时，胫骨内侧干骺端的骨密度增加了8.9%（p = 0.02），而胫骨外侧干骺端（-2.4%）和骨干区域（-2.0%）的骨密度没有显著变化。
UKA未能保留股骨远端干骺端的假体周围骨密度，而胫骨干骺端的骨密度变化较小，这与胫骨内外侧间室的力学平衡一致。证据等级2B：前瞻性病例对照研究。
