The purpose of this study is to perform a feasibility trial of immediate versus delayed weight bearing following fixation of fractures of the lower extremity, pelvis, and acetabulum. The investigator will enroll patients from Shock Trauma over a period of 12 months, and randomize them to immediate weight bearing as tolerated (WBAT) versus delayed WBAT (non-weightbearing for 6-12 weeks). Four specific feasibility criteria will be assessed: enrollment (target 50%), follow-up (target 90% at 3 months), correct documentation of weight bearing (target 90%), correct documentation of primary outcomes, which include reoperation and hardware failure (target 90%). Target enrollment is patients with fractures where the current standard of care is delayed WBAT; for lower extremity this will include fractures of the distal femur, proximal tibia, and distal tibia, including select fractures with intra-articular extension. If feasibility criteria are met over the course of this study, the investigator hopes to move forward with a multicenter randomized controlled trial on this topic.

Weight bearing restrictions are increasingly being scrutinized, as understanding of the potential negative effects of immobilization expand. Recent studies have highlighted that early WBAT may be safe following fixation of lower extremity, pelvis, and acetabulum fractures where the standard of care has been delayed WBAT, but high-quality prospective studies on this topic are needed.

The investigator hypothesizes that in a feasibility trial of immediate versus delayed WBAT following lower extremity, pelvis, and acetabulum fracture fixation, this trial will:

1. be able to enroll 50% of eligible patients and have a 90% follow-up at 90 days post-op of enrolled patients.
2. be able to achieve 90% correct documentation of postoperative weight bearing status and primary outcomes (reoperation or hardware failure).

Specific Aim 1 - Evaluate in a feasibility trial of immediate versus delayed WBAT following lower extremity, pelvis, and acetabulum fracture fixation whether 50% of patients can be enrolled, and 90% of those enrolled will have 90-day follow-up.

Specific Aim 2 - Evaluate in a feasibility trial of immediate versus delayed WBAT following lower extremity, pelvis, and acetabulum fracture fixation whether 90% correct documentation of postoperative weight bearing status and 90% correct documentation of primary outcomes (reoperation or hardware failure) can be obtained.

The investigator anticipates that the feasibility criteria will be met with regard to enrollment, follow-up, and documentation, which will allow us to begin a (likely multicenter) randomized controlled trial evaluating early versus delayed weight bearing following lower extremity, pelvis, and acetabulum fixation.

Inclusion Criteria:

• Fracture of the acetabulum, pelvis, distal femur, distal tibia, including those with intra- articular extension, that meets surgical indications.
• Operative treatment within 7 days of injury at R Adams Cowley Shock Trauma Center, University of Maryland, University of Maryland Medical System, University of Maryland Capital Region Medical Center.
• Provision of informed consent.

Exclusion Criteria:

• Non English Speaking.
• Cognitive ability does not allow for full understanding of study procedures ( Patient has been diagnosed with psychiatric condition, intellectually challenged without adequate family support).
• Patient has other orthopaedic or non-orthopaedic injuries that would preclude him/her from being able to weight bear immediately (e.g. open fractures, polytrauma.
• Significant impaction (>2mm) or comminution at joint surface (e.g. with acetabulum, distal femur, tibial plateau, or tibial plafond fractures).
• Patients who would not be able to immediately weight bear or comply with weight bearing restrictions.
• Not willing to be randomized.
• Surgeon or clinical follow will not occur at participating hospital or location.
• Anticipated problems with follow up in the judgement of study personnel ( patient is homeless).