Through knee amputation compared to above knee amputation

Quality of life (QoL) measured using the EuroQol 5 Dimensions (5L) score (EQ5D-5L) via remote questionnaire (telephone, electronic or postal) at 24 months post-randomisation

Surgical outcomes:
1. Perioperative blood loss assessed using the Riddle formula alongside details of any products used in the perioperative period as documented in clinical notes
2. Planned or unplanned high observation or intensive care admission, assessed from the clinical notes at discharge
3. Procedural pain documented on a 0-10 numerical rating scale at baseline and over the first 5 days post-procedure
4. Within-hospital complications, specifically major adverse cardiovascular events, renal impairment and delirium, assessed from the clinical notes and recorded at the time of discharge
5. Impaired wound healing (including wound infection), assessed from the clinical notes and recorded at the time of discharge
6. Returns to theatre: requirement for revision surgery at either the same or a higher level of amputation, assessed from the clinical notes at discharge, 4, 8, 12, 16, 20 and 24 months
7. 30-day mortality assessed from the clinical notes
8. Total inpatient length of stay assessed from the clinical notes
9. Days alive and out of hospital (measured at 90 days) assessed from the clinical notes
10. Discharge destination, determined from discharge clinical notes and recorded as own home/rehab facility/respite facility/residential care/nursing care
11. Contralateral limb outcomes (minor/major amputation), self-reported at telephone follow-up or assessed from clinical notes at 4, 8, 12, 16, 20 and 24 months

Rehabilitation outcomes:
1. Early mobility measured using the completion of the Basic Amputee Mobility Score (BAMS) by the participants' clinical team at 5 days post-procedure
2. Prosthesis assessment measured using the Special Interest Group in Amputee Medicine Score (SIGAM), assessed from clinical notes review at discharge from hospital and discharge from rehabilitation
3. Referral or not referred for prosthetic assessment assessed from clinical notes during physiotherapy assessment (Note - there is no set timepoint for this assessment. A decision will be made during physiotherapy assessment which could occur at any time)

If referred:
1. Amputee mobility predictor without prosthesis score (AMPnoPRO) during early assessment at the prosthetic centre
2. Achieved expected level of rehabilitation (based on initial AMPnoPRO prediction) at completion of rehabilitation activity.

For prosthetic wearers only:
1. Prosthesis experience measured using the Trinity Amputation and Prosthesis Experience Score (TAPES) and the Socket Comfort Score at months 8, 16 and 24 and at discharge from rehabilitation services
2. Self-reported prosthetic wear time/use at months 8, 16 and 24

Patient-reported outcomes:
Quality of life (QoL) measured using the EuroQol 5 Dimensions (5L) score (EQ5D-5L) at baseline and 4, 8, 12, 16 and 20 months post-randomisation as recorded by the participant via remote questionnaire collected via phone call

The following additional measures will also be assessed by self-reporting via telephone follow-up for all participants:
1. Requirement for formal/informal care assessed using a bespoke/study-specific questionnaire at months 4, 8, 12, 16, 20 and 24
2. Social care related quality of life measured using the Adult Social Care Outcomes Toolkit (ASCOT) SCT4 Questionnaire at months 4, 12 and 20
3. Falls (self-reported number and complications of falls) at months 8, 16 and 24
4. Balance assessed using activity-specific balance confidence score (ABC) at months 4, 12 and 20
5. Activities of daily living measured using the Return to Normal Living Index (RNLI) at months 8, 16 and 24
6. Pain (0-10; Phantom pain assessments) at months 4, 8, 12, 16, 20 and 24
7. Wound healing assessed using a bespoke/study-specific questionnaire at months 4, 12 and 20

The following additional measures will also be assessed by self-reporting via telephone follow-up for prosthesis users only:
1. General prosthesis wear assessed using a bespoke/study-specific questionnaire at months 8, 16 and 24
2. Experience of prosthesis wear measured using the Trinity Amputation and Prosthesis Experience Score (TAPES) at months 8, 16 and 24
3. Prosthesis socket comfort measured using the Socket Comfort Score (SCS) at months 8, 16 and 24