Treatment and Rehabilitation of Arthrofibrosis of the Knee

Treatment and Rehabilitation of Arthrofibrosis of the Knee

52 Treatment and Rehabilitation of Arthrofibrosis of the Knee Scott E. Lawrance, MS, PT, ATC, CSCS  |  K. Donald Shelbourne, MD INTRODUCTION Arthrof...

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Treatment and Rehabilitation of Arthrofibrosis of the Knee Scott E. Lawrance, MS, PT, ATC, CSCS  |  K. Donald Shelbourne, MD

INTRODUCTION Arthrofibrosis of the knee is a common complication that can lead to loss of knee ROM, loss of strength, pain, stiffness, and inability to return to previous levels of activity. There are several definitions of arthrofibrosis in the literature; we have defined it in the past as any symptomatic loss of knee extension or flexion compared to the opposite normal knee. A patient is said to have arthrofibrosis when the limitation in knee joint ROM becomes permanent despite conservative treatments. A common cause of arthrofibrosis is improper rehabilitation or surgery for ACL reconstruction, but it can also occur after other intra-articular knee surgeries or knee injuries. Several factors can lead to limited knee ROM after ACL surgery, including infrapatellar contracture syndrome and patella infera, inappropriate graft placement or tensioning, acute surgery on a swollen inflamed knee, “Cyclops” syndrome, concomitant medial collateral ligament (MCL) repair, and poorly supervised or designed rehabilitation programs. Prevention of arthrofibrosis is the key to successful treatment; therefore prevention should be the focus of every physician and rehabilitation specialist who deals with knee injuries. A good understanding of these factors and how each contributes to limitations in knee ROM is essential to developing a strategy for prevention. Once arthrofibrosis occurs, it takes specialized medical treatment and proper rehabilitation to restore the function within a knee joint. Classification systems have been developed that can help guide treatment and provide a basis for treatment prognosis. The treatment of arthrofibrosis can be divided into preoperative rehabilitation, surgical intervention, and postoperative phases. The goals of treatment are to help restore knee ROM and increase function. The primary focus should be on restoring full passive and active knee extension. Once knee extension is regained and easily maintained, loss of knee flexion can be addressed. Strengthening exercises are slowly added when full ROM is restored because the focus of the procedure and rehabilitation is to address knee motion and stiffness. 

PREVENTION Preventing arthrofibrosis of the knee is based on an understanding of the potential factors that contribute to its causes and is the best way to successfully approach this complication with knee surgery. Several factors should be considered, including graft placement, associated ligamentous injuries, the timing of surgery, and postoperative rehabilitation. ACL graft placement that is anatomically correct is important to prevent ROM problems postoperatively. If the femoral tunnel is placed too anterior, there will be a limitation in knee

flexion. Tibial tunnels placed too far anteriorly will lead to graft impingement against the roof of the intercondylar notch and will not allow full knee extension. Any ACL injury that occurs combined with either medial or lateral side knee injuries is approached by considering the ability of each structure to heal. The rationale on how to manage combined ACL/medial side knee injuries has previously been reported. To summarize, patients who sustain a combination injury to both the ACL and MCL should be treated conservatively initially because the MCL can adequately heal with good stability with proper immobilization. MCL injuries that occur proximally and avulse off the femoral condylar origin or are in the midsubstance of the ligament tend to heal with stiffness. Therefore it is important to restore full knee ROM prior to considering reconstruction of the ACL. Patients who sustain combined ACL/lateral side injuries should undergo a direct “en masse” anatomic repair of the lateral structures and reconstruction of the ACL once the knee inflammation has subsided and adequate knee ROM is obtained. Results of this technique have been previously published (see Shelbourne et al. 2007). Timing of surgery has been previously discussed (Klootwyk 1993, Mohtadi 1991, Shelbourne and Patel 1995). The physical condition of the knee is more important than the number of weeks from injury until reconstruction. A knee that continues to have an active inflammatory phase or does not have full knee motion has been shown to have an increased incidence of arthrofibrosis after surgery. Patients should not be allowed to have surgery until they have little to no swelling in the knee, full knee ROM, good leg control, and appropriate leg strength. Meeting these goals preoperatively makes postoperative rehabilitation easier and more predictable to regain full motion after the reconstruction has taken place. An appropriate postoperative rehabilitation program that emphasizes obtaining full knee ROM and restoring good leg control can help prevent arthrofibrosis. Patients who can achieve full passive knee extension and maintain this on their own cannot develop intra-articular scarring and thus limit arthrofibrosis. Patella infera should also be avoided by stretching the patella tendon postoperatively. Flexion exercises and leg control exercises such as straight leg raise exercises stretch the patellar tendon to its full length and keep the tendon from contracting. When quadriceps muscle inhibition occurs, the tension of the hamstring muscles pulls the knee into flexion and patients are unable to stretch the patellar tendon to its maximal amount of excursion. If the quadriceps inhibition is not regained quickly, the tendon can contract, leading to patella infera. When a patient does have quadriceps inhibition, it is important to do passive full extension and passive flexion >60 degrees to prevent patellar tendon contracture and patellar infera.  353

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SECTION 5  Knee Injuries

CLASSIFICATION The purpose of classification schemes is to allow clinicians to better treat a condition and to make a more accurate prognosis when dealing with a condition. Shelbourne et al. (2007) reported a classification system for arthrofibrosis of the knee after ACL surgery based on ROM of the injured knee as compared to ROM in the noninjured knee (Table 52.1). The passive ROM of the knee is reported as a-b-c with “a” representing the degree of knee hyperextension, “b” representing the degree of knee extension short of 0 degrees, and “c” representing the degree of flexion present. Motion reported as 3-0-140 means that the patient’s knee can hyperextend 3 degrees past zero while being able to flex to 140 degrees. In the normal population, 95% of people have some degree of hyperextension in the knee, so achieving 0 degrees of knee extension is not acceptable and the goal should be to achieve normal hyperextension equal to the noninvolved knee. Type I arthrofibrosis is a loss of knee extension ≤10 degrees combined with normal knee flexion as compared to the opposite knee. This is usually accompanied by anterior knee pain with activity. The knee can usually passively straighten by using overpressure; however, the knee springs back into a flexed position once the pressure has been released. Tightness in the posterior capsule contributes to this inability to obtain full knee extension. Type II arthrofibrosis is a loss of knee extension ≥10 degrees combined with normal flexion. The knee usually cannot be passively extended fully even with overpressure. This loss of extension is typically a result of the development of anterior scar as a mechanical block within the knee, mismatch of the ACL graft within the intercondylar notch, and secondary posterior capsule tightness. Type III arthrofibrosis is a loss of knee extension >10 degrees combined with >25-degree loss of flexion. Patients with type III arthrofibrosis will be similar to the patients with type II but may also have decreased patella mobility and tight medial and lateral capsular structures. No patella infera is measured on the 60-degree lateral radiograph as compared with the opposite knee. Type IV arthrofibrosis presents with similar ROM limitations to the patients with type III; however, patients have patella infera measured radiographically when compared to the noninvolved opposite knee. 

arthrofibrosis, it is important to manage this appropriately in a goal-oriented fashion. Most surgeons prescribe physical therapy exercises, patella mobilizations, extension serial casting, continuous passive motion, and anti-inflammatory medications to help restore knee ROM before any type of surgical intervention. In our clinic, we have not seen that patella mobilizations add any benefit for patients trying to increase knee motion. Patients who can actively contract their quadriceps muscles pull the patella superiorly, and patients who can flex their knee past 90 degrees pull the patella inferiorly. Both of these movements cause greater excursion of the patella than does manual patella mobilizations performed by either a physical therapist or by the patient him or herself. The timing of the surgical intervention is crucial and varies from case to case. Surgery during the inflammatory stage is probably contraindicated, and the importance of returning the knee to a noninflamed state prior to surgery has been described previously. Surgery should only occur when the progress from physical therapy has plateaued and the patient is mentally ready to undergo the procedure.

Preoperative Rehabilitation The rehabilitation of arthrofibrosis is best done as a team with both the treating surgeon and physical therapist working in conjunction with one another throughout the entire process. After the diagnosis of arthrofibrosis is made, preoperative rehabilitation should begin. Physically, patients should focus on restoring knee ROM and obtaining good leg control with the primary focus on improving extension. Counseling on the significance of this condition, the difficulty in treating it, the length of rehabilitation, and prognosis for their recovery is needed. The primary focus is restoration of knee extension until it is maximized. Exercises to increase flexion are not performed yet. Performing exercises for both knee extension and flexion is counterproductive because patients can become frustrated with the lack of any progress. Knee extension exercises include the passive towel stretch (Fig. 52.1), in which the patient stabilizes the thigh while trying to lift the heel off the ground grasping the ends of a towel that is looped around the foot. A passive knee

TREATMENT As previously described, the best treatment for arthrofibrosis is to have a comprehensive treatment plan already in place to prevent arthrofibrosis from occurring. Once a patient does have TABLE

52.1

Type I Type II Type III Type IV

Classification of Arthrofibrosis ≤10 degrees of knee extension loss with normal knee flexion ≥10 degrees of knee extension loss with normal knee flexion >10 degrees of knee extension loss with >25 degrees of flexion loss without patella infera but with patella tightness >10 degrees of knee extension loss with ≥30 degrees of flexion loss accompanied by patella infera and patella tightness

Fig. 52.1  Towel stretch for knee extension. The towel is used to lift the heel of the affected lower extremity to end-range hyperextension by pulling the end of the towel upward toward the shoulder.

52  Treatment and Rehabilitation of Arthrofibrosis of the Knee

extension device (Elite Seat Kneebourne Therapeutics, Noblesville, IN) is used to help restore knee extension preoperatively. The extension device (Fig. 52.2) has the advantage of allowing the patient to lie supine with relaxed hamstring muscles while controlling the amount of passive stretch applied to the knee. The patient controls the force of the passive stretch, which keeps the patient from experiencing increased amounts of pain, muscle spasm, or guarding. Patients are also instructed to stand on their involved leg (Fig. 52.3) while trying to actively contract the quadriceps muscles to lock out the knee whenever standing. Even a small amount of knee extension loss is a problem. Patients with a flexion contracture cannot comfortably stand with the knee locked into full extension. Patients will unconsciously stand with most of the weight on the noninvolved leg

A

355

and will favor the involved knee by keeping it bent. The standing habit instruction is emphasized to patients because any gains patients realize from their home exercises will be lost throughout the day because of favoring the knee if not performed consistently. Leg control is regained by performing physical therapy exercises and focusing on restoring a normal gait pattern. Exercises such as the terminal knee extension exercise (Fig. 52.4) can help encourage patients to activate the quadriceps muscles with better quality. During the gait cycle, it is important to focus on restoring heel strike to help regain leg control. Patients who have a loss of knee extension will land in a foot-flat position and not achieve heel strike. During gait, patients are instructed to slow the pace and shorten their stride to allow concentration on

B

Fig. 52.2  A and B, Elite Seat device allows the patient to recline completely, which relaxes the hamstrings. The patient uses a pulley control to increase the mechanical force for knee extension. Various devices that can be used like an Elite Seat to allow relaxation of hamstrings and allow the patient to control the mechanical force for knee extension within his or her comfort limits.

Fig. 52.3  Standing with the knee locked out into hyperextension is a habit patients should use to keep from favoring the leg and to continually work on knee extension with everyday activities.

Fig. 52.4  Terminal knee extension exercise. An elastic band is wrapped around a stable object and around the back of the patient's knee. The patient extends the knee against the resistance of the band.

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SECTION 5  Knee Injuries

using their quadriceps muscles and achieving heel strike. This keeps compensatory strategies to a minimum; as knee extension and leg control improve, the patient will be able to return to a normal gait pattern. When a patient is able to achieve an active heel lift (Fig. 52.5), good leg control has returned and knee flexion exercises can begin. At this point, knee extension should be maximized and easily maintained through continued exercises. The heel slide exercise and/or wall slide exercise can be used to help restore flexion. However, patients should be instructed not to force knee flexion at the risk of losing knee extension. Exercises for knee flexion should be started daily once extension is maintained; however, if the patient starts to lose knee extension, knee flexion exercises must be halted until knee extension is restored. Strength is not a big concern during this phase of rehabilitation and is not addressed while the patient is working on knee ROM. It is contradictory to have patients work on both knee ROM and knee strengthening exercises at the same time because it often causes the knee to become painful and inflamed with no true gains made in knee ROM or leg strength. However, once patients have achieved maximal knee ROM, single-leg strengthening exercises can be utilized as long as ROM is maintained. Care must be taken by both the clinician and the patient to avoid being too aggressive during this time because small losses of knee ROM will add up quickly if not checked. If losses occur, most strengthening exercises should be stopped immediately. Single-leg strengthening exercises such as the leg press are usually still tolerated well. Patients are also encouraged to exercise in a low-impact manner, such as use of the stationary bicycle, elliptical machine, or stair-stepping machine. Patients are encouraged to improve knee ROM before surgery until it is maximized. Surgery will not be performed until improvement in ROM has plateaued. Patients who have maximized knee extension will report only anterior soreness or discomfort with stretching. If patients continue to report any posterior stretch sensations while performing knee extension exercises, they should continue rehabilitation. Patients who present with type I arthrofibrosis may be able to rehabilitate themselves to the point where surgery is not needed. Patients who regain full equal knee extension and strength that is

symmetric to the opposite noninvolved knee may elect not to have surgery and instead accept the slight limitations their knee places on them. For patients who still have a loss of ROM despite rehabilitation, surgery becomes an option. Ongoing counseling with feedback on the goals of treatment and rehabilitation, progress made, and prognosis should be constant. Mental preparation and understanding of the treatment are as important as the actual treatment. Patients should be in good spirits and ready to tackle the challenges of surgery and the postoperative recovery. Patients still going through the grief cycle should not be operative candidates and may benefit from a referral to a licensed sports psychologist or other mental health care professional before surgical intervention. 

Surgical Intervention The surgical intervention will vary based on the preferences of the physician. However, the goals of surgery must be to restore full passive knee motion equal to the opposite, noninvolved knee. Shelbourne et  al. reported on the outpatient arthroscopic technique and rehabilitation based on the type of arthrofibrosis present. Patients with type I arthrofibrosis are treated by excising the hypertrophied cyclops scar around the base of the ACL until the graft fits in the intercondylar notch and the patient can easily obtain full symmetric knee extension. Patients with type II arthrofibrosis usually require resection of the anterior scar along with resection of the extrasynovial scar tissue anterior to the proximal tibia. Notchplasty or ACL graft débridement is also performed as needed if graft impingement still occurs in full knee extension. Patients with type III arthrofibrosis have scarring similar to those with type II. These patients also have extrasynovial scar present in the fibrotic fat pat between the patella tendon and the tibia. During the arthroscopy, a blunt probe is used to establish a plane between the patella tendon and the scar tissue and the scar tissue is removed distally up to the upper tibia and anteriorly to the horns of the meniscus. Once the retropatellar tendon scar tissue and anterior tibial scar tissue are resected, the fibrotic capsule is excised up to the VMO and the vastus lateralis insertion to free the patella and the patellar tendon completely. Patients with type IV arthrofibrosis require a scar resection similar to those with type III; however, a more extensive resection both medial and lateral to the patella is required for these patients. In patients with type III and type IV arthrofibrosis, a knee manipulation is performed after completion of the scar resection to achieve as much flexion as possible. A notchplasty is required for all patients with types II, III, and IV arthrofibrosis. 

Postoperative Rehabilitation

Fig. 52.5  Active heel lift exercise. The patient contracts the quadriceps muscle to fully extend the knee into full hyperextension.

Postoperative rehabilitation begins immediately after surgery is completed. Patients are placed into antiembolic stocks and a cold/compression device (Cryo/Cuff, Aircast, A division of DJ Ortho, Vista, CA) is applied to the knee. Patients remain in the hospital for an overnight stay to prevent a knee hemarthrosis and reduce pain. After leaving the hospital, patients are restricted to bed rest with only bathroom privileges for the first 5 days. The leg is placed into a continuous passive motion machine set to move the knee from 0 to 30 degrees continuously throughout the day and night. This combination of providing

52  Treatment and Rehabilitation of Arthrofibrosis of the Knee

cold, compression, and elevation has proved effective for preventing swelling and reducing pain. Exercises for knee extension and leg control begin immediately and are performed four times each day. Exercises for knee extension are similar to those used preoperatively and include the towel stretch exercise with an active heel lift and use of a knee extension device. Exercises for leg control include quad sets and straight leg raises. Although both of these exercises help to increase leg control, they are also important to help prevent patellar tendon infera. By contracting the quadriceps muscles and lifting the leg, the patellar tendon is engaged and stretched to its full length, thus preventing a contracture from occurring. Once the patient has maximized knee extension and is able to maintain active heel lift easily, gentle flexion exercises can be initiated twice a day while extension exercises are continued. Heel slide and wall slide exercises can be helpful in regaining knee flexion. Just as is the case preoperatively, patients who start to lose extension postoperatively must stop all flexion exercises and concentrate solely on regaining full knee extension. After 5 days of bed rest, patients are allowed to gradually increase their daily activities over a period of 2 to 3 days so they can return to their normal daily routine. Instructions are given to help achieve a normal gait pattern and the correct standing habits are reviewed again. Patients who were successful preoperatively with standing on the involved leg and walking with a normal gait pattern should be able to achieve these same goals postoperatively with minimal effort. Patients are followed on a weekly basis to check for loss of knee ROM and to update the home exercise program. For type I arthrofibrosis, once knee motion is symmetric to the opposite, noninvolved knee, single-leg strengthening exercises are started along with low-impact conditioning to help restore normal leg strength. Patients with types II, III, and IV arthrofibrosis have significant losses of knee extension before surgery, and although preoperative rehabilitation improves knee extension, the mechanical block within their knee prevents them from fully stretching the posterior knee capsule preoperatively. This means that these patients will typically have to spend more time working on improving knee extension before progressing into the next phase of rehabilitation. Once patients with type II and III arthrofibrosis have met the knee ROM goal of being symmetric to the opposite knee, they are allowed to start into a strengthening program provided full knee ROM is maintained. Patients with type IV arthrofibrosis should be able to achieve full knee extension and maintain this; however, because of the preexisting patella infera, they will not be able to regain full flexion. It is important to know how much flexion a patient is expected to recover, and communication

TABLE

52.2

357

between the physician, patient, and therapist is crucial to ensure that maximal flexion is gained. Returning to sports activities is possible for all patients with arthrofibrosis once they have completed the rehabilitation. Patients should be able to demonstrate knee ROM symmetric to the opposite knee along with achieving strength that is within 10% of the opposite leg when tested isokinetically. Patients should carefully monitor knee ROM as they increase sports activities. Impact sports such as basketball, soccer, football, or volleyball are recommended to be performed on an every-other-day basis for the first 2 to 4 weeks to allow the knee time to recover. The cold/compression device should be used to help control inflammation and swelling within the knee after participation. Patients whose knees remain sore despite the off day or who cannot maintain full knee ROM will need further modification of their activities until they are less sore and can better maintain knee ROM. As soreness decreases and ROM is maintained, patients are allowed to increase the amount of participation accordingly. Patients are followed in the clinic until they have returned to all of their desired sports activities. 

RESULTS From January 1, 2003, until December 31, 2007, 27 patients with arthrofibrosis after ACL reconstruction were referred to our practice and treated using the surgical technique and rehabilitation program described previously. The patient sample is summarized in Table 52.2. The average ROM at initial treatment in the involved knee was 0-8-121 compared to 5-0-146 in the noninvolved knee. All patients underwent preoperative physical therapy to maximize knee ROM followed by arthroscopic scar resection and postoperative physical therapy. Postoperative ROM improved in the involved knee to 4-0-136. International Knee Documentation Committee (IKDC) subjective knee questionnaires were given to all patients and the average improved from 50 points (out of 100 points) preoperatively to 69 points postoperatively. Preoperatively, the difference in knee extension ROM among patients was distributed evenly among the ROM categories as established by the IKDC (Fig. 52.6, A). No patient demonstrated less than 3 degrees of knee extension preoperatively. Postoperatively, all patients had an increase in their involved knee extension ROM. Twenty patients (74%) had a difference in knee extension postoperatively between 0 and 2 degrees as compared to the opposite knee, and seven patients increased their knee extension into the 3- to 5-degree category. The difference in knee flexion preoperatively among patients can be seen in Fig. 52.6, B. Postoperatively, all patients saw an

Change in Knee Extension and Flexion ROM With IKDC Subjective Score for Patients Preoperative to Postoperative Based on Arthrofibrosis Classification (Lawrance) PREOPERATIVE DIFFERENCES

Classification Type I Type II Type III Type IV All patients

Number of Patients (n) 7 5 13 2 27

Extension 7.0 10.6 16.4 9.0 12.3

POSTOPERATIVE DIFFERENCES

Flexion

Extension

4.0 23.0 40.6 37.0 27.4

1.4 2.0 1.9 3.5 1.6

Flexion 1.4 8.6 16.8 35.0 11.9

IKDC Preoperative

Postoperative

57 55 47 42 50

78 68 68 62 69

SECTION 5  Knee Injuries

DIFFERENCE IN KNEE FLEXION

DIFFERENCE IN KNEE EXTENSION 14

25 Preoperative Postoperative Number of patients

15 10 5

10 8 6 4 2

B

ff di

ff 

50

di 25

–5

5 –2 16

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0–

25

5

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ff 5 –2 16

11

–1

5

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ff di

ff 6–

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Degrees

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Number of patients

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Preoperative Postoperative

12

6–

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Degrees

Fig. 52.6  Distribution in preoperative and postoperative knee ROM measurements for extension (A) and flexion (B).

improvement in their knee flexion. No patient lacked more than 50 degrees of flexion postoperatively. Individuals who regained normal knee motion, according to IKDC criteria, scored higher postoperatively on their IKDC subjective questionnaires than those who did not have normal motion. Eight patients (30%) achieved normal knee motion as compared to the opposite knee, with an average postoperative IKDC score of 78. Four patients (15%) regained nearly normal extension (lacking 3 to 5 degrees), lacked greater than 16 degrees of flexion, and had an average IKDC subjective score of 43, illustrating the importance of achieving symmetric knee motion. 

CONCLUSIONS Arthrofibrosis of the knee includes a vast amount of pathology, and a good understanding of the contributing factors is vital to treat this condition successfully. The most effective method of treating this condition is taking the necessary steps initially to prevent it from occurring, because once it has occurred significant functional deficits and disability can occur. The focus of treatment should be to restore normal knee ROM with the primary focus on obtaining full knee extension first, including full hyperextension, and then obtaining full knee flexion second. Patients should be educated on the total management plan for arthrofibrosis including the prognosis for the functional status of their knee once treatment is concluded. REFERENCES A complete reference list is available at https://expertconsult .inkling.com/. FURTHER READING Chambat P, Vargas R, Desnoyer J. Arthrofibrosis after anterior cruciate ligament reconstruction. The Knee Joint. 2012:263–268. Web. De Carlo MS, Sell KE. Normative data for range of motion and single-leg hop in high school athletes. J Sport Rehab. 1997;6:246–255. Graf B, Uhr F. Complications of intra-articular anterior cruciate reconstruction. Clin Sports Med. 1988;7:835–848.

Harner CD, Irrgang JJ, Paul J, et al. Loss of motion after anterior cruciate ligament reconstruction. Am J Sports Med. 1992;20:499–506. Jackson DW, Schaefer RK. Cyclops syndrome: loss of extension following intra-­ articular anterior cruciate ligament reconstruction. Arthroscopy. 1990;6:171–178. Joseph, MF. Clinical evaluation and rehabilitation prescription for knee motion loss. Physical Therapy in Sport. 2012;13.2:57–66. Web. Livbjerg, EA, Froekjaer S, et  al. Pre-operative patient education is associated with decreased risk of arthrofibrosis after total knee arthroplasty. The Journal of Arthroplasty. 2013;28.8:1282–1285. Web. Noyes FR, Wojtys EM, Marshall MT. The early diagnosis and treatment of developmental patella infera syndrome. Clin Orthop Relat Res. 1991:241–252. Noyes FR, Mangine RE, Barber SD. The early treatment of motion complications after reconstruction of the anterior cruciate ligament. Clin Orthop Relat Res. 1992;277:217–228. Nwachukwu, BU, Mcfeely ED, et al. Infrapatellar contracture syndrome. An unrecognized cause of knee stiffness with patella entrapment and patella infera. Am J Sports Med. 1987;15:331–341. Rubinstein Jr RA, Shelbourne KD, VanMeter CD, et al. Effect on knee stability if full hyperextension is restored immediately after autogenous bone-patellar tendon-bone anterior cruciate ligament reconstruction. Am J Sports Med. 1995;23:365–368. Salter RB, Hamilton HW, Wedge JH, et al. Clinical application of basic research on continuous passive motion for disorders and injuries of synovial joints: a preliminary report of a feasibility study. J Orthop Res. 1984;1:325–342. Said S, Svend EC, Faunoe P, et al. Outcome of surgical treatment of arthrofibrosis following ligament reconstruction. Knee Surg Sports Traumatol Arthrosc. 2011;19.10:1704–1708. Web. Sapega AA, Moyer RA, Schneck C, et  al. Testing for isometry during reconstruction of the anterior cruciate ligament. Anatomical and biomechanical considerations. J Bone Joint Surg Am. 1990;72:259–267. Shearer DW, Micheli LJ, Kocher MS. Arthrofibrosis after anterior cruciate ligament reconstruction in children and adolescents. Journal of Pediatric Orthopaedics. 2011;31.8:811–817. Web. Shelbourne KD, Patel DV. Timing of surgery in anterior cruciate ligament-­ injured knees. Knee Surg Sports Traumatol Arthrosc. 1995;3:148–156. Shelbourne KD, Patel DV, Martini DJ. Classification and management of arthrofibrosis of the knee after anterior cruciate ligament reconstruction. Am J Sports Med. 1996;24:857–862. Shelbourne KD, Porter DA. Anterior cruciate ligament-medial collateral ligament injury: nonoperative management of medial collateral ligament tears with anterior cruciate ligament reconstruction. A preliminary report. Am J Sports Med. 1992;20:283–286. Shelbourne KD, Wilckens JH, Mollabashy A, et al. Arthrofibrosis in acute anterior cruciate ligament reconstruction. The effect of timing of reconstruction and rehabilitation. Am J Sports Med. 1991;19:332–336. Strum GM, Friedman MJ, Fox JM, et al. Acute anterior cruciate ligament reconstruction. Analysis of complications. Clin Orthop Relat Res. 1990;253: 184–189.

REFERENCES Klootwyk TE, Shelbourne KD, DeCarlo MS. Perioperative rehabilitation concerns. Oper Tech Sports Med. 1993;1:22–25. Mohtadi NG, Webster-Bogaert S, Fowler PJ. Limitation of motion following anterior cruciate ligament reconstruction. A case-control study. Am J Sports Med. 1991;19:620–624.

Shelbourne KD, Haro MS, Gray T. Knee dislocation with lateral side injury. Results of an en masse surgical technique of the lateral side. Am J Sports Med. 2007;35:1105–1116. Shelbourne KD, Patel DV. Management of combined injuries of the anterior cruciate and medial collateral ligament. J Bone Joint Surg Am. 1995;77:800– 806.

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