Changes in spino-pelvis-lower extremity alignment in patients with knee osteoarthritis: a prospective radiographic study.

Abstract

Purpose: Osteoarthritis (OA) is a prevalent, debilitating ailment among the elderly. Humans need a correct sagittal spino-pelvis-lower extremity alignment to stand upright. Pathology in trunk or lower extremity section might disrupt this harmony, causing compensatory alterations in other segments. The aim of the present study was to evaluate spino-pelvis-lower extremity alignment and association among the various spino-pelvic, knee, and ankle radiological angles in patients with knee osteoarthritis (OA).

Materials and methods: This prospective study enrolled 70 adults over 50 years of age of either sex who complained of knee pain and met the American College of Rheumatology criteria for symptomatic OA of at least one knee. The radiological assessment comprised anteroposterior and lateral lower extremity full-length scans, as well as the Kellgren-Lawrence radiographic classification of OA. We measured hip, knee, ankle, and spino-pelvic angles using Horos software. We calculated descriptive statistics and linear correlation between continuous variables.

Results: There was a significant association (p < 0.05) between age and the majority of the spino-pelvic, knee, and ankle angles and between age and severity of OA. Significant variables linked with 'SFA' include HKAA (p = 0.008), mLDFA (p < 0.001), TJLA, FS-TS, Cond-Plateau, and femoral bowing (p = 0.007). We found significant associations between 'PFA' and mMPTA (p = 0.005), Cond-Plateau (p = 0.005), Tibial Bowing (p = 0.003), and 'LL' with HKAA, mLDFA, FS-TS, and Cond-Plate. SSA was significantly associated with mLDFA, mMPTA, TJLA, Cond-Plateau, and HKAA; while, FI' was significantly associated with FS-TS, femoral bowing, and tibial bowing (p < 0.001). The variables 'SS' was substantially linked with TTA (p = 0.008), TT (p = 0.004), PP (< 0.001), GP (p < 0.001), and GT (p = 0.010). 'PI' was substantially linked to TT (p = 0.001), GP (p = 0.005), and GT (p = 0.042), and 'PT' to TT (p < 0.001) and GT (p = 0.012). 'SFA' and 'PFA' only correlated with TT (p = 0.012 and 0.010). Lower limb angles were significantly associated with TT, PP, GP, GT, mLDFA, and mMPTA (p = 0.031, p = 0.026, p = 0.009, p = 0.009, TT, GP, GT, p < 0.001). GP was the sole significant association for 'TJLA' (p = 0.016). 'FS-TS' substantially correlated with PP (p = 0.015), GP (p < 0.001), and GT (p < 0.001). "Femoral Bowing" was significantly linked to PP (p = 0.017), GP (p = 0.007), and GT (p < 0.001), and "Cond-Plateau" was significantly linked to GP (p = 0.002) and GT. "Tibial Bowing" was significantly linked to TTA (p < 0.001), TAS (p = 0.003), LDTA (p = 0.002), TC (p < 0.001), GP (p = 0.007), and GT (p < 0.001). Age, gender, BMI, and the severity of knee OA significantly influenced the association among these various angles.

Conclusion: Osteoarthritis of the knee disrupts the harmonious alignment of the spine and pelvis with the lower limbs, resulting in compensatory changes in the ankle and spine. The severity of knee osteoarthritis and the patient's gender, age, and BMI impact compensatory adaptations.

Trial registration number and date of registration: CTRI/2021/08/036088 [Registered on: 31/08/2021] - Trial Registered Prospectively.