Tibial condylar valgus osteotomy in the treatment of varus unicompartmental knee osteoarthritis / 中华骨科杂志

ABSTRACT

Objective:To investigate the clinical effects and indications of tibial condylar valgus osteotomy (TCVO) in treating varus unicompartmental knee osteoarthritis.Methods:A retrospective analysis was conducted in 32 patients (45 knees) who suffered from varus unicompartmental knee osteoarthritis and underwent TCVO from June 2016 to June 2018. These patients were aged 65.8±8.3 (range from 52 to 79) years, including 12 males (18 knees) and 20 females (27 knees). All enrolled individuals presented obvious expansion of the lateral joint space with joint line convergence angle (JLCA) of 7.19°±2.69°. Based on the full-length standing X-ray imaging of the lower limbs at before and 2 years after surgery, the percentage of mechanical axis (%MA), femorotibial angle (FTA), hip-knee-ankle angle (HKA), lateral distal femoral angle (LDFA) and medial proximal tibial angle (MPTA) were measured and analyzed to evaluate the improvements of lower extremity alignments. The medial tibial plateau depression (MTPD), posterior proximal tibial angle (PPTA), JLCA and joint space width (JSW) were measured and analyzed to evaluate the congruency of the knee joint and shape of the tibial plateau based on positive and lateral radiographs of knee joint. In addition, visual analogue scale (VAS) and Western Ontario and McMaster Universities (WOMAC) score were evaluated to assess the clinical effects of TCVO pre-operatively and at 1 year or 2 years after surgery.Results:All patients were followed up for 33.4±7.4 (range from 25 to 40) months. Comparing to the preoperative radiological data, %MA at 2 years after surgery increased from 3.78%± 14.34% to 66.16%±9.90%, FTA from 185.41°±4.45° to 170.81°±2.87°, HKA from 169.69°±1.70° to 181.16°±2.39°, MPTA from 83.03°±3.20° to 90.84°±3.67° all with statistical significance ( P<0.05). There was no significant difference for PPTA between before (89.22°±1.52°) and 2 years (88.97°±1.57°) after surgery ( t=0.638, P=0.526). MTPD improved from -7.81°±3.27° to 5.78°±2.19° ( t=19.218, P<0.001). However, there was no significant difference for PPTA between before (81.63°±3.28°) and 2 years (82.25°± 2.21°) after surgery ( t=0.881, P=0.382). JLCA reduced from 7.19°±2.69° to 0.22°±2.09°. The medial and lateral JSW were corrected from 2.45±0.23 mm and 5.86±0.25 mm to 3.73±0.27 mm and 4.68±0.34 mm ( P<0.05), respectively. Additionally, VAS and WOMAC scores improved from 6.46±2.21 and 52.66±16.69 preoperatively to 2.94±1.72 and 19.31±14.87 at 1 year after surgery, and to 1.39±1.45 and 13.66±15.44 at 2 years after surgery, respectively ( P<0.05). Conclusion:Satisfactory early therapeutic outcomes could be achieved by TCVO in varus unicompartmental knee osteoarthritis with subluxated lateral joint and increased JLCA. TCVO can correct intra-articular varus deformity, adjust mechanical axis and relieve knee joint pain and dysfunction.