Pradhan Siddharth Satyakam, Tripathy Sujit Kumar, Jain Mantu, Behera Hrudeswar, Velagada Sandeep, Srinivasan Anand
Dept. of Orthopedics, All India Institute of Medical Sciences, Bhubaneswar-751019, India.
Arthroplasty. 2022 Jun 2;4(1):22. doi: 10.1186/s42836-022-00123-w.
Limb length alteration following total knee arthroplasty (TKA) has been under-reported. Few studies have shown a significant association between limb length discrepancy (LLD) and poor functional outcome. This prospective study evaluated the impact of radiographic and perceived LLD on functional outcome in TKA. The variables affecting LLD were also evaluated.
The preoperative and postoperative limb lengths of TKA patients (112 knees, 81 patients, KL grade ≥ 3) were measured in full-length digital radiographs. The Hip-Knee-Ankle (HKA) angles were also measured. The functional outcome (Western Ontario and McMaster Universities Arthritis Index) and perception about LLD were evaluated after six months.
The mean preoperative radiographic LLD in the unilateral and bilateral TKA groups was 0.75 cm ± 0.60 cm and 0.58 cm ± 0.52 cm (P = 0.197), respectively. Similarly, postoperative LLD was 0.76 cm ± 0.85 cm in the unilateral group and was 0.59 cm ± 0.92 cm (P = 0.402) in the bilateral group. Only 19.7% of patients had postoperative radiographic LLD of ≥ 10 mm, and 80.2% of patients had LLD of < 10 mm. The functional outcome was significantly affected when LLD exceeded 10 mm (correlation coefficient 0.54, P < 0.001). Linear regression analysis revealed no significant effects of age, sex, height, weight, BMI, preoperative LLD and difference in deformity between the limbs on postoperative LLD. 34.5% of patients perceived LLD in the preoperative period, which decreased to 3.7% in the postoperative period. Perceived LLD did not correlate to radiographic LLD and functional outcome.
There is no significant difference in radiographic LLD between unilateral and bilateral TKA. The functional outcome is adversely affected by radiographic LLD of ≥ 10 mm. Age, sex, BMI, preoperative LLD and difference in deformity angle do not affect the LLD. About one-third of patients perceive LLD in the preoperative period, which improves significantly after TKA.
II.
全膝关节置换术（TKA）后肢体长度改变的报道较少。很少有研究表明肢体长度差异（LLD）与功能预后不良之间存在显著关联。这项前瞻性研究评估了影像学和感知到的LLD对TKA功能预后的影响。还评估了影响LLD的变量。
在全长数字X线片上测量TKA患者（112个膝关节，81例患者，KL分级≥3级）术前和术后的肢体长度。还测量了髋-膝-踝（HKA）角。6个月后评估功能预后（西安大略和麦克马斯特大学骨关节炎指数）以及对LLD的感知。
单侧和双侧TKA组术前影像学LLD的平均值分别为0.75 cm±0.60 cm和0.58 cm±0.52 cm（P = 0.197）。同样，单侧组术后LLD为0.76 cm±0.85 cm，双侧组为0.59 cm±0.92 cm（P = 0.402）。只有19.7%的患者术后影像学LLD≥10 mm，80.2%的患者LLD<10 mm。当LLD超过10 mm时，功能预后受到显著影响（相关系数0.54，P<0.001）。线性回归分析显示，年龄、性别、身高、体重、BMI、术前LLD和双下肢畸形差异对术后LLD无显著影响。34.5%的患者在术前感知到LLD，术后降至3.7%。感知到的LLD与影像学LLD和功能预后无关。
单侧和双侧TKA的影像学LLD无显著差异。影像学LLD≥10 mm会对功能预后产生不利影响。年龄、性别、BMI、术前LLD和畸形角度差异不影响LLD。约三分之一的患者在术前感知到LLD，TKA后明显改善。
II级。
