Calf Muscle Vein Thrombosis After Hip and Lower-Limb Fracture Surgery: A Systematic Review and Meta-Analysis.

BackgroundCalf muscle vein thrombosis (CMVT) is frequently grouped with distal deep vein thrombosis in fracture-related studies, leaving its specific burden and clinical relevance uncertain. This systematic review and meta-analysis evaluated the occurrence, associated factors, and clinical outcomes of CMVT in patients undergoing surgery for hip and lower-limb fractures.MethodsPubMed, Embase, Web of Science Core Collection, the Cochrane Library, ClinicalTrials.gov, Google Scholar, and reference lists were searched from inception to June 8, 2026. Eligible studies reported extractable CMVT-related data in patients undergoing surgery or perioperative management for hip or lower-limb fractures. Random-effects meta-analyses were performed using logit-transformed proportions. Risk factors with extractable 2 × 2 data were pooled as unadjusted odds ratios (ORs).ResultsEight observational studies involving 3,695 patients were included; seven studies with 3,435 patients contributed to quantitative synthesis. All studies were conducted in mainland China. Overall, 691 CMVT events were reported. The pooled occurrence was 18.2% (95% CI, 12.4%-26.0%; prediction interval, 4.4%-51.6%; I2 = 96.1%). The pooled preoperative prevalence was 29.1%, whereas the postoperative or perioperative incidence/detection rate was 12.3%. Exploratory pooled analyses showed higher CMVT odds in female patients (OR, 1.53; 95% CI, 1.03-2.29) and in those with intertrochanteric rather than femoral neck fractures (OR, 1.36; 95% CI, 1.10-1.68). Narrative synthesis suggested possible associations with thrombus progression, postoperative complications, prolonged hospitalization, early mortality, and poorer functional outcomes.ConclusionCMVT is relatively common in patients undergoing surgery for hip and lower-limb fractures, particularly when screened preoperatively in older patients with hip fractures. However, because all included studies were observational and conducted in mainland China, and substantial heterogeneity was present, global generalizability is limited. These findings should therefore be interpreted cautiously and confirmed in prospective, multicenter studies.