Traditional versus Accelerated Rehabilitation following ACL Reconstruction: A One-Year Follow-Up

Postoperative rehabilitation programs are believed to influence clinical outcome. The purpose of this paper was to outline the evolution of postoperative rehabilitation following anterior cruciate ligament reconstruction. Because of the controversy surrounding accelerated ACL rehabilitation and the concept of gaining terminal knee extension immediately following reconstruction, the authors felt justified in carrying out a retrospective comparison of traditional rehabilitation versus an accelerated approach. The objective variables under consideration included range of motion, isokinetic strength, and ligamentous stability. Results showed that active and passive range of motion, including hyperextension, returned more quickly and more fully in the accelerated group. Ligamentous stability was found to be equal to or better in the accelerated group despite a more aggressive rehabilitation approach. The results of this study indicated that an accelerated rehabilitation program following ACL reconstruction resulted in improved range of motion and strength gains without compromising stability. J Orthop Sports Phys Ther 1992;15(6):309-316.     

Update on accelerated rehabilitation after anterior cruciate ligament reconstruction

Rehabilitation of the anterior cruciate ligament (ACL) reconstructed knee continues to be a topic of intense interest among surgeons and therapists. Since 1987, over 880 patients who have undergone ACL reconstruction using the central one-third of the bone patellar tendon bone graft have followed our accelerated rehabilitation protocol. Follow-up of the patients reveals early return to athletic activity and maintenance of long-term stability. Our 1987 accelerated rehabilitation program continues to be modified, with less constraints placed on the postoperative patient in our present rehabilitation protocol. These recent changes are once again prompted by noncompliant patients who, with close follow-up evaluation, continue to yield excellent results. Our present accelerated rehabilitation protocol is divided into four phases. The initial phase encompasses the preoperative period. The second phase involves the initial 2 weeks post ACL reconstruction. The third phase dates from 2-5 weeks postoperation, and the final phase (greater than 5 weeks) involves a safe return to athletic play. Our goal with the accelerated rehabilitation protocol remains to decrease postoperative complications without jeopardizing the long term stability of the ACL reconstructed knee. J Orthop Sports Phys Ther 1992;15(6):303-308.     

What I have learned about the ACL: utilizing a progressive rehabilitation scheme to achieve total knee symmetry after anterior cruciate ligament reconstruction

Anterior cruciate ligament surgery and rehabilitation have changed drastically during the past 30 years. The patellar tendon autograft fixed with buttons provides tight bone-to-bone placement of the graft and quick bony healing, which allows accelerated rehabilitation to obtain full range of motion and strength. Although surgical stability is easily reproducible, long-term patient satisfaction is difficult to guarantee. Full knee range of motion should be compared to that of the contralateral normal knee, including full hyperextension. We followed the progress of all patients to gauge the utility of our rehabilitation program. In order of importance, the lack of normal knee range of motion (within 2° extension and 5° of flexion compared with that of the normal knee), partial or total medial meniscectomy, partial or total lateral meniscectomy, and articular cartilage damage were related to lower subjective scores. Rehabilitation after ACL reconstruction must first strive to achieve full symmetrical knee range of motion before aggressive strengthening can begin. Our current perioperative rehabilitation starts at the time of injury and preoperatively includes aggressive swelling reduction, hyperextension exercises, gait training, and mental preparation. Goals after surgery are to control swelling while regaining full knee range of motion. After quadriceps strengthening goals are reached, patients can shift to sport-specific exercises. When using a graft from the contralateral knee, the conflicting goals of strengthening the donor site and achieving full knee range of motion are divided between the knees. Thus, normal range of motion and strength can be achieved more easily and more quickly than when using an ipsilateral graft. Regardless of the graft source, a systematic rehabilitation program that emphasizes the return to symmetrical knee motion, including hyperextension, is necessary to achieve the optimum result.     

Knee rehabilitation after anterior cruciate ligament reconstruction and repair

Reprinted with permission from The American Journal of Sports Medicine 9:3 140-147, 1981. Presented at the Interim Conference of the American Orthopaedic Society for Sports Medicine, February 8, 1980, Atlanta, GA.Address correspondence to: Lonnie Paulos, MD, 2350 Auburn Ave., Cincinnati, OH 45219.The purpose of this paper is to present the specifics and rationale of our postoperative rehabilitation program after anterior cruciate ligament (ACL) reconstruction 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 believe are important.The early phases of our program are based upon time and control of forces, both of which are necessary 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 requires the absolute control of forces to prevent disruption 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 controlled 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 cruciate ligament forces and healing strength is still low. A balance of quadriceps and hamstring forces is necessary for proper knee kinematics. De-emphasis of quadriceps exercises and emphasis of hamstring muscles 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 degrees 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, coordination, and endurance. Phase 3, the maximum protection 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 patient's condition and goals.Phase 4, the return to activity phase, begins nine to 12 months after surgery. It consists of the advanced rehabilitation period and the running period. The advanced rehabilitation period is designed to achieve maximum strength and further enhance neuromuscular coordination and endurance. The running period begins when the operated leg has at least 75 percent 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 program consists of triweekly strength-building sessions, brace protection during sporting, and avoidance of high-risk activities. J Orthop Sports Phys Ther 1991; 13(2):60-70.     

The early treatment of motion complications after reconstruction of the anterior cruciate ligament.

The use of active and passive knee motion in the immediate postoperative period and a treatment plan for early postoperative limitations in knee motion has proven highly effective in restoring motion after anterior cruciate ligament (ACL) reconstruction. Of 207 knees, 189 (91%) regained a full range of motion of 0 degrees-135 degrees. The remaining 18 knees (9%) did not regain motion as rapidly as the others and were placed in an early postoperative phased treatment program. Six knees had serial extension casts, nine had early gentle manipulation under anesthesia, and three had arthroscopic lysis of intraarticular adhesions and scar tissue. Fourteen of these 18 knees regained a full range of knee motion. Two of the remaining four knees lacked 5 degrees of full extension, whereas the other two, in patients who had failed to follow medical advice and the rehabilitation program, had permanent and significant limitation of motion. The incidence of postoperative motion problems was related to the extent of the surgical procedure. The incidence was 4% in patients who had only ACL reconstruction, 10% in cases in which added lateral extraarticular procedure had been done, 12% where a meniscus repair had been done, and 23% where a medial collateral ligament repair was done.     

Pulley system isokinetic training in knee rehabilitation--initial results

AIM: The purpose of this study was to evaluate the results of a knee rehabilitation program after knee surgery, based on an isokinetic pulley System (Moflex, Recotec/Bernina, Switzerland). METHOD: In this prospective study, 73 patients participated in a standardized rehabilitation program (ACL reconstruction, ACL/all: n = ;51; patellar tendon, ACL/P: n = 30; semitendinosus tendon, ACL/S: n = 21; arthroscopic meniscus resection: n = 22). The major aspect of the program was an isokinetic pulley system with an implemented, linearly working knee device. RESULTS: Isokinetic training with the used device affords strict monitor feed-back to avoid critical torque values. Concentric training strength and workload which were attained without relevant pain were increased by about 130% within a mean of 16 rehabilitation days. At the end of the rehabilitation program, the maximum concentric strength of the affected knee measured by a rotating isokinetic system (Cybex, Kaphingst, Lahntal) increased by about 69% and amounted to about 90% of that of the unaffected knee. CONCLUSION: These first results demonstrate the value of the isokinetic pulley system in the rehabilitation after knee surgery as described above. The equipment may be used already in an early postoperative stage by the use of a passive or active-assistive mode. First results of strength increases using an isokinetic pulley system in knee rehabilitation are presented.     

Current Concepts for Rehabilitation following Anterior Cruciate Ligament Reconstruction

Rehabilitation following ACL reconstruction has undergone significant changes during the last decade. The purpose of this article is to review the accelerated rehabilitation program that was described by Shelbourne and Nitz in 1990. A summary of current basic science related to the ACL and ACL reconstruction is presented. Additionally, we present our preoperative, intra-operative, and postoperative recommendations for optimizing results while at the same time minimizing the risk for loss of motion following ACL reconstruction. J Orthop Sports Phys Ther 1992;15(6):270-278.     

The anatomy of the ACL and its importance in ACL reconstruction

The anterior cruciate ligament (ACL) anatomy is very significant if a reconstruction is attempted after its rupture. An anatomic study should have to address, its biomechanical properties, its kinematics, its position and anatomic correlation and its functional properties. In this review, an attempt is made to summarize the most recent and authoritative tendencies as far as the anatomy of the ACL, and its surgical application in its reconstruction are concerned. Also, it is significant to take into account the anatomy as far as the rehabilitation protocol is concerned. Separate placement in the femoral side is known to give better results from transtibial approach. The medial tibial eminence and the intermeniscal ligament may be used as landmarks to guide the correct tunnel placement in anatomic ACL reconstruction. The anatomic centrum of the ACL femoral footprint is 43 % of the proximal-to-distal length of lateral, femoral intercondylar notch wall and femoral socket radius plus 2.5 mm anterior to the posterior articular margin. Some important factors affecting the surgical outcome of ACL reconstruction include graft selection, tunnel placement, initial graft tension, graft fixation, graft tunnel motion and healing. The rehabilitation protocol should come in phases in order to increase range of motion, muscle strength and leg balance, it should protect the graft and weightbearing should come in stages. The cornerstones of such a protocol remain bracing, controlling edema, pain and range of motion. This should be useful and valuable information in achieving full range of motion and stability of the knee postoperatively. In the end, all these advancements will contribute to better patient outcome. Recommendations point toward further experimental work with in vivo and in vitro studies, in order to assist in the development of new surgical procedures that could possibly replicate more closely the natural ACL anatomy and prevent future knee pathology.     

Design and implementation of a neuromuscular training program following anterior cruciate ligament reconstruction.

Neuromuscular training programs are increasingly integrated into clinical practice for lower extremity rehabilitation. A few rehabilitation programs have been evaluated for patients with anterior cruciate ligament (ACL) deficiency and for injury prevention, but there is limited scientific evidence of the effect of neuromuscular training following ACL reconstruction. Therefore, a neuromuscular training program was developed for patients after ACL reconstruction. The objective of the neuromuscular training was to improve the ability to generate a fast and optimal muscle firing pattern, to increase dynamic joint stability, and to relearn movement patterns and skills necessary during activities of daily living and sports activities. The main areas considered when designing the postoperative rehabilitation program after ACL reconstruction were: ACL graft healing and ACL strain values during exercises, proprioception and neuromuscular control, and clinical studies on the effect of neuromuscular training programs. The rehabilitation program consists of balance exercises, dynamic joint stability exercises, jump training/plyometric exercises, agility drills, and sport-specific exercise. The patients exercise 3 times a week for 6 months. The scientific and clinical evidence for the rehabilitation program are described and the main exercises in the program are outlined.     

Recent advances in the rehabilitation of isolated and combined anterior cruciate ligament injuries

The rehabilitation process begins immediately following ACL injury, with emphasis on reducing swelling and inflammation; improving motion; regaining quadriceps control; allowing immediate weight-bearing; and restoring full passive knee extension and, gradually, flexion. The goal of preoperative rehabilitation is to prepare the patient mentally and physically for surgery. Once the ACL surgery is performed, it is important to alter the rehab program based on the type of graft used and any concomitant procedures performed. This will aid in preventing several postoperative complications, such as loss of motion, patellofemoral pain, graft failure, and muscular weakness. The goal of this article has been to provide an overview of the application and the scientific basis for formulating a rehabilitation protocol following ACL surgery. For an athlete to return to competition, it is imperative that he or she regain muscular strength and neuromuscular control in their injured leg while maintaining static stability. In the past, rehabilitation programs attempted to prepare the athlete for return to sports by using resistance exercise alone. Current rehabilitation programs focus not only on strengthening exercises, but also on proprioceptive and neuromuscular control drills in order to provide a neurologic stimulus so that the athlete can regain the dynamic stability needed in athletic competition. We believe that it is important to use this approach not only possible causes that might predispose the individual to future injury.     

Neuromuscular rehabilitation of a female Olympic ice hockey player following anterior cruciate ligament reconstruction

STUDY DESIGN: Case study. OBJECTIVE: To demonstrate the unique aspects of rehabilitating a female athlete participating in ice hockey following anterior cruciate ligament (ACL) reconstruction. BACKGROUND: The patient was a 28-year-old female who sustained a traumatic injury to her left knee while playing ice hockey. After 6 weeks of rehabilitation (15 visits), the athlete elected to undergo ACL reconstruction following buckling episodes that she experienced during both skating and walking. METHODS AND MEASURES: Following ACL reconstruction using a patellar tendon autograft, the patient was treated for 6 months in 44 visits. Initial treatments consisted of effusion management, neuromuscular control of lower extremity muscles, and regaining passive range of motion, especially extension. Although instability testing revealed a negative pivot shift and a 2-millimeter side-to-side difference on KT-1000 examination, the patient reported a sensation of buckling when she attempted skating at 4 months (27 visits) following ACL reconstruction. Off-ice strength and functional testing of the lower extremity did not demonstrate deficits. At that time, a specific neuromuscular program for returning a patient to ice hockey was implemented. RESULTS: Following 17 physical therapy visits, which combined sport-specific and sex-specific neuromuscular rehabilitation, the patient was able to return to competitive ice hockey. Six months following ACL reconstruction, the patient reported no feeling of instability during skating. The patient reported a Lysholm score of 100 and Tegner activity score of 9. An on-ice functional test revealed the athlete's score was 80% of her pre-injury score. CONCLUSIONS: Failure of static knee stabilizers can be a cause of instability. Following ACL reconstruction, a neuromuscular rehabilitation program may prevent residual knee instability once the static stabilizers have been restored. A sport-specific neuromuscular rehabilitation program for the athlete participating in ice hockey should be considered.     

Rehabilitation of the knee after anterior cruciate ligament reconstruction

From the Kerlan-Jobe Orthopaedic Clinic, 501 E. Hardy Street, Suite 200, Inglewood, CA 90301. New information regarding the isometric placement of the anterior cruciate ligament (ACL) substitute, revascularization process, and biomechanical stresses have all contributed to and been incorporated in the rehabilitation program after ACL reconstruction. Treatment protocols specifically designed for the patient following ACL reconstruction are imperative to return the individual to his or her preinjury status. Care is taken to limit the amount of stress placed on the ligament substitute especially at end of range extension. A program incorporating techniques for developing range of motion and strength while still preserving stability at the knee joint is still of the utmost importance. This program is a revision of a previously reported regimen from this facility (Brewster, Moynes, Jobe, J Orthop Sports Phys Ther 5:121-126, 1983) and is based upon clinical experience and research information. J Orthop Sports Phys Ther 1989;11(1):8-18.     

Current concepts in the treatment of anterior cruciate ligament disruption

Treatment of anterior cruciate ligament injuries has changed considerably in recent years. The purpose of this paper is to discuss the past and present treatment for anterior cruciate ligament (ACL) disruptions in athletic individuals. In addition, this paper will discuss current trends in rehabilitation, such as immediate motion, weight bearing, and close kinetic chain exercises, and provide the scientific rationale for these rehabilitation principles. The treatment of individuals who have suffered an ACL disruption has changed dramatically over the years. The treatment of ACL ruptures has made a full circle. The first reconstructive procedure described used a patellar tendon graft. Then primary ACL repairs were advocated. With the limited success of that procedure, the nonoperative treatment was popularized, with reconstruction performed only after the conservative program failed. With this treatment plan, clinicians noted early degenerative joint changes and an increase in meniscus tears in the ACL deficient knee. Thus, reconstructive surgery using a patellar tendon graft was again advocated. Today, the current trend in the treatment of ACL tears is an arthroscopically assisted procedure to reconstruct the ACL using a bone-tendon-bone graft, such as a patellar tendon. The surgery employs accurate graft placement, tensioning, and fixation, which allows the therapist the opportunity to utilize immediate motion and weight bearing, in addition to strengthening exercises. This paper attempts to explain the rehabilitation process following ACL reconstruction using current scientific and clinical research. The program is based on the anatomy, biomechanics, and healing process of the knee, joint, and ACL. The clinical implications of this paper are numerous. First, we believe the information will assist clinicians in developing their own programs. Second, the data will assist the reader in understanding the sequential healing process. Finally, this paper documents that immediate aggressive rehabilitation is not deleterious to the ACL graft, and early therapy improves the functional outcome. J Orthop Sports Phys Ther 1992;15(6):279-293.     

Combined injuries of the medial collateral ligament and the anterior cruciate ligament

Aim of this retrospective study is to evaluate the effect of acute and late anterior cruciate ligament (ACL) reconstruction in patients with a combined injury of the ACL and the medial collateral ligament (MCL). All MCL injuries were treated non-operatively. In 27 patients (group I) we performed early ACL reconstruction (within the first 3 weeks after injury). The postoperative rehabilitation protocol included brace treatment for all patients over a period of 6 weeks. In 37 patients we performed late ACL reconstruction (after a minimum of 10 weeks). In this group initial non-operative MCL treatment (6 weeks brace treatment) was followed by a period of accelerated rehabilitation. Patients with late ACL reconstruction had a lower rate of loss of motion after finishing the postoperative rehabilitation programme and a lower rate of re-arthroscopies for a loss of extension (group I: 4 patients, group II: 1 patient). The difference in the mean quadriceps muscle strength (group I: 83.3%, group II: 86.3%) was not statistically significant. After a mean interval of 22 months, we saw no difference in the frequency of anterior or medial instabilities or in the loss of motion. The Lysholm score was significantly better in the group with late ACL reconstruction (group I: 85.3, group II: 89.9). The position on the Tegner activity scale decreased in both groups, to 5.5 in group I (preoperatively: 6.0) and to 5.6 in group II (preoperatively: 5.9). With regard to the lower rate of motion complications in the early postoperative period, the lower rate of re-arthroscopies, and the significantly better results in the Lysholm score, we prefer late ACL reconstruction in the treatment of combined injuries of the ACL and the MCL.     

Isolated anterior cruciate ligament reconstruction in the chronic ACL-deficient knee with degenerative medial arthrosis

Isolated anterior cruciate ligament (ACL) reconstruction may provide long-term symptom relief and improved function in patients with medial knee arthrosis and ACL-deficiency, while delaying or possibly eliminating the need for further surgical intervention. Fifty-three patients who had medial unicompartmental arthrosis and chronic ACL-deficient knees underwent ACL reconstruction alone. Subjective evaluation at mean 10 years postoperatively indicated statistically significant improvement compared to preoperative evaluation and better scores for patients who obtained normal knee range of motion. Objective evaluation, performed for 33 patients at a mean of 5.5 years postoperatively, indicated 25 normal or nearly normal International Knee Documentation Committee ratings; 2 patients have undergone subsequent osteotomy or total knee arthroplasty. Isolated ACL reconstruction provides long-term symptomatic pain relief, increased activity, and improved function. Anterior cruciate ligament reconstruction can effectively provide stability to the ACL-deficient knee with degenerative medial arthrosis without compromising range of motion or strength. Obtaining and maintaining full range of motion equal to the normal knee is important for the optimal result.     

Donor-site morbidity and anterior knee problems after anterior cruciate ligament reconstruction using autografts

The authors review the current knowledge on donor site–related problems after using different types of autografts for anterior cruciate ligament (ACL) reconstruction and make recommendations on minimizing late donor-site problems. Postoperative donor-site morbidity and anterior knee pain following ACL surgery may result in substantial impairment for patients. The selection of graft, surgical technique, and rehabilitation program can affect the severity of pain that patients experience. The loss or disturbance of anterior sensitivity caused by intraoperative injury to the infrapatellar nerve(s) in conjunction with patellar tendon harvest is correlated with donor-site discomfort and an inability to kneel and knee-walk. The patellar tendon at the donor site has significant clinical, radiographic, and histologic abnormalities 2 years after harvest of its central third. Donor-site discomfort correlates poorly with radiographic and histologic findings after the use of patellar tendon autografts. The use of hamstring tendon autografts appears to cause less postoperative donor-site morbidity and anterior knee problems than the use of patellar tendon autografts. There also appears to be a regrowth of the hamstring tendons within 2 years of the harvesting procedure. There is little known about the effect on the donor site of harvesting fascia lata and quadriceps tendon autografts. Efforts should be made to spare the infrapatellar nerve(s) during ACL reconstruction using patellar tendon autografts. Reharvesting the patellar tendon cannot be recommended due to significant clinical, radiographic, and histologic abnormalities 2 years after harvesting its central third. It is important to regain full range of motion and strength after the use of any type of autograft to avoid future anterior knee problems. If randomized controlled trials show that the long-term laxity measurements following ACL reconstruction using hamstring tendon autografts are equal to those of patellar tendon autografts, we recommend the use of hamstring tendon autografts because there are fewer donor-site problems.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 9 (November-December), 2001: pp 971–980     

Transphyseal anterior cruciate ligament reconstruction in a skeletally immature knee using anterior tibialis allograft

Anterior cruciate ligament (ACL) injury in the skeletally immature individual is being recognized with increasing frequency. Nonoperative treatment of ACL injuries in skeletally immature patients have not been favorable. Surgical treatment options for complete ACL tears include primary ligament repair, extraarticular tenodesis, transphyseal reconstruction, partial transphyseal reconstruction, and physeal-sparing reconstruction. The advantage of transphyseal reconstruction is placement of the graft tissue in an isometric position, which provides better results, according to the literature. The potential disadvantage is angular or limb-length discrepancy caused by physeal violation. Controversy exists in allograft selection about whether bone or soft tissue passes into physes. The use of standard tunnels provides reliable results, but carries the risk of iatrogenic growth disturbance from physeal injury.This article presents 4 cases of transphyseal ACL reconstruction using anterior tibialis allograft in skeletally immature patients that had satisfactory functional outcomes with no growth disturbances. This is the first report of transphyseal ACL reconstruction using anterior tibialis allograft in skeletally immature patients in the English-speaking literature. All patients underwent transphyseal ACL reconstruction using anterior tibialis tendon allograft. None of the patients had angular deformities. No early physeal arrest was measured between the preoperative and postoperative radiographs. At last follow-up, the results of the Lachman test were normal for 3 patients and nearly normal for 1 patient. All patients demonstrated full range of knee motion (comparing the reconstructed knee to the contralateral knee). The results of the pivot-shift test were normal for 3 patients and nearly normal for 1 patient. No patients reported giving way.     

Rationale and protocol for postoperative anterior cruciate ligament rehabilitation

A rehabilitation program for postoperative anterior cruciate ligament (ACL) reconstruction permits adequate tissue healing time and allows early protected muscular conditioning. The program is based on kinematic, biomechanical, and kinesiologic factors as they pertain to ACL function. The program is divided into five phases. The early phases, zero to 12 weeks, are intended to control translational forces across the ACL and to allow necessary time for ligament revascularization and soft-tissue healing. During this period, isometric and isotonic training of the hamstrings and quadriceps muscle groups in a restricted active arc of motion is permitted. Passive motion is encouraged, and progressive weight bearing is allowed. Conditioning of the upper body as well as the nonsurgical lower limb is stressed. During the advanced phases, 12-31 weeks, isotonic muscle training continues throughout a full range of motion. Greater strength, coordination, and endurance to achieve dynamic stability of the knee, preparing the patient for unrestricted activity, are stressed. Approximately 52 weeks of active rehabilitation after ACL reconstruction surgery are usually required to return to a preinjury level of function.     

Graft selection for anterior cruciate ligament reconstruction

The ideal anterior cruciate ligament (ACL) graft substitute would have no morbidity associated with its procurement, be readily available for use, and be capable of strong fixation with sufficient inherent strength to withstand an accelerated postoperative rehabilitation program. In addition, the long-term results of ACL reconstruction using the graft substitute should be favorable. Unfortunately, such an ideal graft material does not currently exist. At present, available choices for ACL graft substitutes include autograft tissue, allograft tissue, and synthetic devices. This article presents the reader with a review of the factors involved in selecting a material to serve as a graft substitute for ACL reconstruction and explores the advantages and disadvantages associated with the use of various graft tissues.     

Biomechanics and anterior cruciate ligament reconstruction

For years, bioengineers and orthopaedic surgeons have applied the principles of mechanics to gain valuable information about the complex function of the anterior cruciate ligament (ACL). The results of these investigations have provided scientific data for surgeons to improve methods of ACL reconstruction and postoperative rehabilitation. This review paper will present specific examples of how the field of biomechanics has impacted the evolution of ACL research. The anatomy and biomechanics of the ACL as well as the discovery of new tools in ACL-related biomechanical study are first introduced. Some important factors affecting the surgical outcome of ACL reconstruction, including graft selection, tunnel placement, initial graft tension, graft fixation, graft tunnel motion and healing, are then discussed. The scientific basis for the new surgical procedure, i.e., anatomic double bundle ACL reconstruction, designed to regain rotatory stability of the knee, is presented. To conclude, the future role of biomechanics in gaining valuable in-vivo data that can further advance the understanding of the ACL and ACL graft function in order to improve the patient outcome following ACL reconstruction is suggested.