This is a prospective randomized controlled trial with the purpose to determine if patients undergoing fibular collateral ligament (FCL) reconstruction alone or combined FCL and anterior cruciate ligament (ACL) reconstructions can safely begin full controlled weightbearing for the first six weeks after surgery.

Patients will be randomly assigned to one of two rehabilitation protocols for the first six weeks post-surgery:

1. partial weightbearing
2. full controlled weightbearing

An immobilizer brace in extension will be used from post-operative day 0 through 13 and a CTi ligament knee brace (Össur Americas, Foothill Ranch, California) will be used from 14 to 42 days post-surgery to protect against side-to-side motion while weight bearing.

Specific Aims

1. Primary Aim: To determine if there is a difference in millimeters of varus gapping on anteroposterior (AP) stress radiographs at six months post-surgery between patients who are partial weight bearing versus full controlled weight bearing during the first six weeks of post-surgical rehabilitation. This distance will be compared to varus gapping measured on the contralateral uninjured control knee.
2. Secondary Aim: To determine if there is a difference in pain, edema, and range of motion, gait, quadriceps strength, and patient reported outcomes between groups.

The Investigators hypothesize that there will be no clinically significant difference (< 2 mm change) in varus gapping between the control and treatment groups. Results of this study will help to expedite return to pre-injury levels of activity and decrease adverse sequelae associated with non-weight bearing such as osteopenia, muscle atrophy, loss of ankle range of motion, and increased risk of deep vein thrombosis.

The current standard of care for FCL reconstruction is early controlled partial weight -bearing for the first six weeks after surgery.

Inclusion Criteria:

• ≥ 14 years old, <60
• Reconstruction of FCL alone
• Combined FCL + ACL reconstructions
• Males or females
• Is willing and able to comply with the clinical trial plan and able to understand and sign the Patient Informed Consent Form.

Exclusion Criteria:

• < 14 years old, > 60
• Pregnant
• Revision FCL reconstructions
• Concurrent biceps femoris or lateral capsular repairs
• Concurrent PCL or MCL reconstructions
• Concomitant meniscus root or radial repair surgery with transtibial technique