a continuous passive motion (cpm) device is used immediately after surgery to help with flexibility. the preferred method of preventing muscle loss is isometric exercises that put zero strain on the knee. knee extension within two weeks is important with many rehab guidelines. perturbation training can help improve gait asymmetries of the knee joint. approximately six weeks is required for the bone to attach to the graft. however, the patient can typically walk on their own and perform simple physical tasks prior to this with caution, relying on the surgical fixation of the graft until true healing (graft attachment to bone) has taken place. at this stage, the first round of physical therapy can begin. this usually consists of careful exercises to regain flexibility and small amounts of strength. one of the more important benchmarks in recovery is the twelve weeks post-surgery period. after this, the patient can typically begin a more aggressive regimen of exercises involving stress on the knee, and increasing resistance. jogging may be incorporated as well. after four months, more intense activities such as running are possible without risk. after five months, light ball work may commence as the ligament is nearly regenerated. after six months, the reconstructed acl is generally at full strength (ligament tissue has fully regrown), and the patient may return to activities involving cutting and twisting if a brace is worn. recovery varies highly from case to case, and sometimes resumption of stressful activities may take a year or longer. risks if the proper rehabilitation procedure is not followed out post surgery, the acl becomes less mobile and the bones begin to rub against each other. the abnormal bone movement can also damage the tissue, this damage can lead to osteoarthritis. rehabilitation the recovery process for the acl is usually broken down into different phases of rehabilitation. each phase has its own objectives, however is intertwined with other phases since the goals are as progressive as the recovery itself. the rehabilitation process is at the pace of the patient. timelines are sometimes given to help give an idea of where one can be during rehabilitation. timelines are not used to discourage or encourage those who aren't ready to advance their recovery process. such acts may cause serious injury or re-injury of the acl. phase 1 this phase begins immediately post surgery while the patient is still on crutches and in a removable knee brace, which they're projected to be using for seven to ten days. during this phase the patient will begin seeing a physical therapist that will discuss the main goals of rehabilitation. some of these goals include: reducing pain and inflammation, increasing range of motion, strengthening surrounding muscles, and beginning weight bearing exercises. generally, in phase 1 strengthening consists of isometric exercises. extension deficit is a frequent issue after surgery and is often related to arthrogenic muscle inhibition. specific exercises and cryotherapy are proven to be effective in addressing arthrogenic muscle inhibition. if the patient used a patellar tendon graft for their reconstructed acl, therapist will also work on mobilizing the patellar tendon to keep it from shortening. some equipment that can be used and exercises that can be performed are: use of cryo-cuff - provides cold compression isometric contraction of quads quad sets - stand against wall, push extended knee against rolled towel - progress to straight leg raised to 30deg. wall slides - to increase knee flexion assisted knee flexion towel squeeze - sit in chair, squeeze rolled towel between knees for 5 seconds. relax & repeat. vmo strengthening exercise supported bilateral calf-raises walk without crutches swimming (freestyle front crawl) this particular swimming technique encompasses all the muscles in the knee and will increase not only mobility but also the strength of the surrounding muscles, which include the quadriceps, hamstrings, gastrocnemius, tibialis anterior (shin muscle), abductor hallucis, abductor digiti minimi, and flexor digitorum brevis (foot muscles). phase 2 many of the goals from phase i will be continued to the following phases until they have been reached. some of these goals are reducing pain, swelling, and increasing the knee's range of motion is still crucial during this phase. physical therapist may begin to incorporate core exercises as well as light weight exercises to strengthen the surrounding muscles and hips. some examples of these exercises include the usage of resistance/stretch bands, stationary biking, and elliptical. during this phase the patient may begin performing more strenuous exercises such as half-squatting and partial lunges. some exercises that can be performed are: mini squats - progress to full squats → single-leg half squat mini lunges - progress to full lunges leg press - double-leg → single step-ups bridges - double-leg → single - floor → swiss ball hip abduction w/ theraband hip extension w/ theraband wobble board - assisted → un-assisted → eyes closed (assisted → unassisted) stork stand - assisted → un-assisted → eyes closed (assisted → unassisted) → unstable surface static proprioceptive hold/ball throwing functional exercises that can be performed at this time include: - walking - bike - roman chair phase 3 patients will continue to work on decreasing pain/swelling and building up their strength. lateral movement, jogging in a straight line, single-leg squats and exercises will start to be incorporated as patient begins to regain confidence in the knee. building strength in the hips with lateral stepping as well as step-ups and step-downs will still be a strong focus in this phase. some exercises that can be performed are: continue exercises from phase 2, progress as necessary jump & land drills - jump from block & stick landing - double-leg landing → single-leg plyometric drills - jumping over blocks, sideways & forward - hopping up & down steps/stairs phase 4 by this time the range of motion should be greater than 110 degrees flexed and the patient's bodily mechanics like walking and light jogging should be back to normal (before operation). single leg exercises will be continued as well as balancing activities to strengthen the core and lower body. stamina and endurance should be improved for exercises such as: biking, jogging, and step-ups/downs. if by this time the patient does not have 110 degrees of flexion in the knee, they are advised to see their therapist or surgeon. there's a chance that the knee could need another operation to increase the elasticity of the ligament. the goal of this phase is a return to activity, however it requires an ability to perform some functional performance tests such as: agility tests illinois agility test zig zag agility test these tests are used to test the ability of the knee to withstand cutting and planting maneuvers. single leg step-down tests these tests can be used to identify any hip and core musculature weaknesses before cleared for return-to-play. standing vertical jump the patient jumps straight in the air from a standing start and lands on two feet as stable as possible. heiden hop test the patient jumps as far as possible with the uninjured leg and lands on the injured leg. a patient's ability to stick the landing is indicative of good knee function. isokinetic testing this is used to evaluate muscle strength. the individual should have at least 90% quadricep strength of the uninjured leg. they should also have equal hamstring strength to their uninjured leg as well. phase 5 this is the last phase of the recovery rehabilitation. phase v includes returning to sports after being cleared by therapist or surgeon. in order for this to happen the patient must have full range of motion, continue maintaining strength and endurance, and be able to increase proprioception with agility drills. patient is still to be aware that going down hill or down stairs while the knee is aggravated may cause further injury like a meniscus tear. cost of procedure the cost of an acl reconstruction surgery will vary due to a few different reasons such as where a patient lives, which graft is used, if the meniscus is also torn, and the coverage of the patient's insurance. a study has shown in 2016 that metropolitan areas, of at least one million residents, located on the western coast of the united states of america and areas like minnesota, indiana, and michigan were more expensive than the east and south east coast of the united states. another study, conducted by baylor university, found that acl reconstruction procedures using the bone-patella tendon-bone technique took 2.5 hours longer than using a hamstring graft. the operation room costs and hospital charges for that amount of extra time came to about $1,580 more expensive. this also applies to having a torn meniscus during the procedure. fixing the torn cartilage will increase the procedure time, increasing cost. insurance plays the biggest role in cost for an acl reconstruction since that it will be covering majority of the costs. the coverage of a patient's plan, deductibles, and insurance company will determine how much the patient will pay in copays. despite the complexity of the procedure and numerous doctor's visits involved, 80–90% of patients who have had the surgery said they had favorable results.