The purpose of the study is to determine if there is difference in immediate postoperative pain levels (48 hours) between patients who wear a knee immobilizer splint compared to patients who do not wear a knee immobilizer splint after an anterior cruciate ligament reconstruction surgery.

This study will attempt to evaluate the efficacy of knee immobilization on patient postoperative pain levels following an ACL reconstruction. There is a lack of consensus in the area of postoperative knee bracing/immobilization. A survey of Canadian surgeons indicates that the primary reason for postoperative knee immobilization is to reduce pain. To the investigators' knowledge, there are no studies comparing the use of immediate (0-48 hours) postoperative knee immobilization versus no immobilization and pain control in this patient population.

Inclusion Criteria:

- Clinical: Patients' aged 18-40, ACL deficiency as determined by MRI or physical exam (positive lachmann and pivot shift tests) resulting in giving way episodes (acute or chronic) unresponsive to non-operative management and therefore requiring primary ACL reconstruction.

- Arthroscopic: Concomitant meniscal resection.

Exclusion Criteria:

- Clinical: Previous surgery on either knee (not including a diagnostic arthroscopy arthroscopy or simple partial meniscectomy,) Concomitant lower extremity fracture, Ipsilateral collateral ligament injury within past 3 months, Time from ACL injury less than 6 weeks, Allergy/intolerance to Tylenol 3 with codeine and to Percocet, Third Party or Medical Legal.

- Radiological: Skeletal immaturity (open growth plates).

- Arthroscopic/surgical: Concomitant posterior cruciate ligament or collateral ligament repairs, Osteochondral lesions requiring microfracture, Meniscal repair, Patients not having both their semitendinosus and gracilis harvested.