1. Conclusions: A popliteus tendon or popliteofibular ligament reconstruction with the bone block centered over the femoral footprint of the popliteus tendon was highly non-isometric.

2. Applying tension to a popliteus or popliteofibular graft internally rotated the tibia, with no significant difference between the rotations caused by the tensioning of the two grafts.

3. The popliteus and popliteofibular graft tensioning protocols used in this study overly constrained external rotation and failed to produce optimal load-sharing with the posterior cruciate graft.

4. Popliteus and popliteofibular grafts were more favorably aligned than a lateral collateral ligament graft to resist external rotation, and they had similar effects.

5. The graft isometry measurements were then repeated with the bone block centered over the femoral footprint of the lateral collateral ligament or popliteus tendon.

6. Make a longitudinal incision in the capsule, beginning well proximal to the joint line to avoid damaging the meniscus or the popliteus tendon.

7. Injuries of the lateral supporting structures, including the fibular collateral ligament, iliotibial band, biceps femoris, and popliteus tendon, also are depicted with MRI.

8. Clinical Relevance: Holding the tibia in neutral rotation when tensioning a popliteus or popliteofibular graft will help limit internal tibial rotation.

9. Results: With the lateral collateral ligament intact, removal of the popliteus tendon from its femoral origin significantly increased external tibial rotation.