Ishii Yoshinori, Noguchi Hideo, Sato Junko, Ishii Hana, Todoroki Koji, Toyabe Shin-Ichi
Ishii Orthopaedic & Rehabilitation Clinic, 1089 Shimo-Oshi, Gyoda, Saitama 361-0037, Japan.
Ishii Orthopaedic & Rehabilitation Clinic, 1089 Shimo-Oshi, Gyoda, Saitama 361-0037, Japan.
Knee. 2017 Oct;24(5):1153-1159. doi: 10.1016/j.knee.2017.06.012. Epub 2017 Aug 10.
Proximal tibial bone mineral density (BMD) has been studied for its potential impact on subsidence and loosening of the tibial component after total knee arthroplasty (TKA). However, no known studies of proximal tibial BMD after TKA have evaluated the effect of major impact factors such as body weight (BW), muscle strength, and level of activity. We aim to determine whether factors such as level of activity, quadriceps strength, BW, gender, age, and prosthetic design affect proximal tibial BMD over the mid- to long-term following TKA.
We evaluated 36 patients (72 knees) who were undergoing bilateral TKA performed by a single surgeon. Median follow up time was 115months (range, 60-211months) for a minimum of five years. We measured BMD in the proximal tibia and used a hand-held dynamometer to measure quadriceps isometric strength, recording the maximum value of three measurements for each patient.
Univariate analyses using Spearman's correlation coefficient for continuous variables revealed a weak negative correlation between age and BMD (r=-0.316, P=0.007) and a moderate positive correlation between BW and BMD (r=0.430, P<0.001). However, no significant correlations were found between the other factors above and BMD for continuous and discrete variables. Based on multivariate analyses, only BW had a significant effect on BMD (β=0.342, P=0.003).
BW is the most impact factor on the proximal tibial BMD after mid- to long-term follow up TKA. Therefore, the management of BW may contribute to prevention of decline of tibial BMD for TKA patients owing to aging.
胫骨近端骨密度（BMD）对全膝关节置换术（TKA）后胫骨部件的下沉和松动的潜在影响已得到研究。然而，尚无已知研究评估TKA后胫骨近端BMD受体重（BW）、肌肉力量和活动水平等主要影响因素的作用。我们旨在确定活动水平、股四头肌力量、BW、性别、年龄和假体设计等因素在TKA后的中长期是否会影响胫骨近端BMD。
我们评估了由单一外科医生进行双侧TKA的36例患者（72个膝关节）。中位随访时间为115个月（范围60 - 211个月），最短随访时间为5年。我们测量了胫骨近端的BMD，并使用手持测力计测量股四头肌等长力量，记录每位患者三次测量的最大值。
对连续变量使用Spearman相关系数进行单因素分析显示，年龄与BMD之间存在弱负相关（r = -0.316，P = 0.007），BW与BMD之间存在中度正相关（r = 0.430，P < 0.001）。然而，上述其他因素与连续和离散变量的BMD之间未发现显著相关性。基于多因素分析，仅BW对BMD有显著影响（β = 0.342，P = 0.003）。
中长期随访TKA后，BW是对胫骨近端BMD影响最大的因素。因此，控制BW可能有助于预防TKA患者因衰老导致的胫骨BMD下降。
