300 Section - Fragility-fracture risk following major lower-limb amputation

Major lower-limb amputation (MLLA) confers increased risk of fracture. MLLA is associated with unloading osteopenia at the ipsilateral hip, elevated falls risk, plus potential “prolonged immobility” which is a World Health Organisation recognised cause for secondary osteoporosis.

Fragility-fracture risk assessment (FRAX) has been implemented in Primary Amputation clinic at Bristol Centre for Enablement since July 2023. We aimed to explore disuse osteoporosis in MLLA secondary to immobility using SIGAM and FRAX assessment.

Design:

We undertook retrospective cohort study of MLLA patients within the FRAX validity age range (40-90 years) assessed August 2023-August 2024. All cases were deemed to have “Secondary Risk” for Osteoporosis on FRAX assessment. All cases were followed up until September 2025 to identify SIGAM outcomes achieved.

Results:

171 MLLA cases of which 158 eligible for FRAX assessment with average age 63.2 years; 127(80.4%) male, 31(19.6%) female. Co-morbidities included diabetes(56.3%), renal disease(16.5%), stroke(17.7%), and other cardiovascular disorders (including peripheral vascular disease) (70.9%). 19(12.0%) patients died within 1 year of Primary appointment. 42(26.6%) had history of other amputation events (toes, transmetatarsal, limb).

7(4.4%) achieved “normal” mobility with prosthetic (SIGAM F), and 94(59.5%) had mobility < 50metres (SIGAM levels A-C). 34(21.5%) were non-limb wearers (SIGAM A).

103(65.2%) had FRAX completed. FRAX outcomes were 51(49.5%) Low risk (lifestyle advice), 41(39.8%) Intermediate referred for DEXA, 6(5.8%), High-risk referred to Primary-Care-Physician for treatment, 5(4.9%) Very High-risk referred to Speciality Bone Health services.

Conclusion:

Amputees are potentially a high fracture risk population, despite a predominantly male and relatively young cohort. We recommend all lower limb amputees have FRAX assessment for primary prevention of fracture, with inclusion of secondary risk for osteoporosis in MLLA. MLLA patients experience unloading osteopenia particularly at the ipsilateral hip, with SIGAM scores evidencing potential prolonged immobility secondary to MLLA. Future research will need to assess prevalence of FRAX variables against incident fractures.