The prevalence of an isolated gastrocnemius tightness in patients with knee or hip pathology

Introduction: Clinically, isolated gastrocnemius tightness (IGT) is identified by limited ankle dorsiflexion when the knee is extended, which improves with knee flexion. The Weight Bearing Lunge Test is the preferred method for assessing IGT due to its high reliability. While IGT is well-documented in foot pathology, its prevalence in knee and hip pathologies remains underexplored. The aim of this study was to determine the prevalence and extent of isolated gastrocnemius tightness before elective surgery in patients with knee or hip pathology and to confirm correlations between isolated gastrocnemius tightness and patients' demographics, pain, and activity levels. Methods: Eighty patients admitted to a tertiary orthopaedic centre for elective surgery (total arthroplasty or arthroscopy) were included. Demographics, pain, and activity levels were measured. Ankle dorsiflexion index was measured bilaterally with a Weight-Bearing Lunge Test by using a gravity inclinometer. Results: Gastrocnemius tightness was defined as an ankle dorsiflexion index ≥ 13°. The mean bilateral ankle dorsiflexion index was 8° ± 4°. Based on this criterion, isolated gastrocnemius tightness was identified in 14% of patients. When a less strict definition was applied (ankle dorsiflexion index ≥ 10°), the prevalence of isolated gastrocnemius tightness increased to 37% of patients. Total hip arthroplasty patients had significantly higher dorsiflexion index on both limbs (treated: 11° ± 5°, control; 10° ± 3°) than other groups (total knee arthroplasty 7° ± 3°; hip arthroscopy 7° ± 4°; knee arthroscopy 6° ± 3°). Gastrocnemius tightness was present in 21% of patients with hip pathology, compared to 8% in those with knee pathology. No significant differences were found between treated and control legs. Conclusions: Ankle dorsiflexion index correlated positively with age and pain but negatively with activity level. One in five patients with hip pathology and one in ten with knee pathology exhibited isolated gastrocnemius tightness. Total hip arthroplasty patients presented with significantly higher ankle dorsiflexion index than other groups. Increased age and pain levels were associated with increased gastrocnemius tightness, while a higher activity level appeared protective.