Knee rehabilitation after anterior cruciate ligament reconstruction and repair
Authors: Paulos Lonnie , Noyes Frank R. , Grood Edward , Butler David L. 
Published: June 2007

The purpose of this paper is to present the specifics and rationale of our postoperative rehabilitation pro gram after anterior cruciate ligament (ACL) recon struction and compare it with an international survey of 50 knee experts. It is important to stress that what we present is opinion. This opinion, however, is based on principles, guidelines, and specifics which we be lieve are important.

The early phases of our program are based upon time and control of forces, both of which are neces sary for ligament healing. The classic parameters of return to play do not indicate healing of ligament tissue and must not be substituted for time restraints.

After ACL repair and reconstruction, there are five phases of rehabilitation: maximum protection (12 weeks), moderate protection (24 weeks), minimum protection (48 weeks), return to activity (60 weeks), and activity and maintenance.

The maximum protection phase consists of the early healing period and controlled motion period. The early healing period is governed by a principle which re quires the absolute control of forces to prevent dis ruption of the suture line or attachment site. This time will vary according to the surgical technique. We do not allow motion during this period. During the con trolled motion period, we allow motion but control external forces to protect ligament healing.

The moderate protection phase consists of the crutch-weaning and walking periods. The major goal of the moderate protection phase is to prepare the patient for walking. The principles which govern Phase 2 are that walking activities create large anterior cru ciate ligament forces and healing strength is still low. A balance of quadriceps and hamstring forces is nec essary for proper knee kinematics. De-emphasis of quadriceps exercises and emphasis of hamstring mus cles is appropriate; however, both muscle groups must be strengthened. The crutch-weaning period is designed to allow the gradual increase of motion and strength to sustain walking activities.

A paradox of exercise exists for strength building. To push weight from 30° of flexion into full extension will protect the patellofemoral joint but will create large forces on the ACL. Our compromise is to push low weight through a full range of motion. We begin full weightbearing no sooner than the 16th week.

The final three phases of our program are designed to develop dynamic stability through strength, coor dination, and endurance. Phase 3, the maximum pro tection phase, consists of the protected activity period from the 24th through the 36th week, and the light activity period from the 37th through the 48th week. Restrictions include no running, no jumping, and the use of a brace full-time. The light activity period allows further time to protect the slow healer. This may be shortened or lengthened, depending upon the pa tient's condition and goals.

Phase 4, the return to activity phase, begins 9 to 12 months after surgery. It consists of the advanced rehabilitation period and the running period. The ad vanced rehabilitation period is designed to achieve maximum strength and further enhance neuromuscu lar coordination and endurance. The running period begins when the operated leg has at least 75% of the strength and power of the normal leg.

The activity and maintenance phase consists of the return to sport and maintenance periods. On return to sport, the patient must gradually resume full activity by advancing from skill drills. The maintenance pro gram consists of triweekly strength-building sessions, brace protection during sporting, and avoidance of high-risk activities.