Knee laxity and function after conservative treatment of anterior cruciate ligament injuries. A prospective study

Clinic and Home-Based Exercise with Blood Flow Restriction Resolves Thigh Muscle Atrophy after Anterior Cruciate Ligament Reconstruction with the Bone-Patellar Tendon-Bone Autograft: A Case Report

Anterior cruciate ligament reconstruction (ACLR) results in thigh muscle atrophy. Of the various interventions proposed to mitigate thigh muscle atrophy, exercise with blood flow restriction (BFR) appears safe and effective. Some literature suggests daily exposure to exercise with BFR may be indicated during the early phase of ACLR rehabilitation; this case report outlines the methodology utilized to prescribe clinic- and home-based BFR within an outpatient rehabilitation program. A 15-year-old male soccer player suffered a left knee injury involving the anterior cruciate ligament and both menisci. He underwent ACLR and completed exercise with BFR as part of his clinic- and home-based rehabilitation program, which included practical blood flow restriction during home-based rehabilitation. After 16 weeks of rehabilitation, surgical limb thigh girth values were objectively larger than the non-surgical limb (surgical, 52.25 cm; non-surgical 50 cm), as well as the multi-frequency bioelectrical impedance analysis of his lower-extremity lean body mass (surgical limb, 10.37 kg; non-surgical limb, 10.02 kg). The findings of this case report suggest that the inclusion of clinic- and home-based BFR within an outpatient rehabilitation program may be indicated to resolve thigh muscle atrophy early after ACLR.

The management of combined ACL and MCL injuries: A systematic review

Background

The management of combined anterior cruciate ligament (ACL) and medial collateral ligament (MCL) injuries remains contentious. Clinical outcomes of surgical, conservative, and combined approaches have been described in a range of prospective and retrospective studies. The aim of the current systematic review was to evaluate these outcomes and assess the study methodologies.

Methods

A comprehensive literature search of the following databases was performed: PubMed, OVID, Cochrane Database of Systematic Reviews and Google Scholar. Studies were assessed using the Coleman Methodology Score.

Results

52 articles were included (3 randomised controlled trials, 8 prospective comparative studies, 17 retrospective comparative studies and 24 case series). Outcome measures were heterogeneous amongst articles. The most common outcomes assessed were AP laxity, Lysholm score and medial/valgus laxity. Complications at varying follow-up times with differing grades of MCL injury were reported in 25 (48%) studies. Evidence was conflicting, with no consensus from the available published literature regarding the best method of treatment for a combined ACL and MCL injury.

Conclusions

Heterogeneous outcome measures and limited randomised controlled trials prevent advocacy of a single treatment option. Good outcomes have been reported from repair, reconstruction and conservative management of the MCL together with ACL reconstruction. Further prospective comparative data is required to evaluate MCL management choice and prognostic signs for successful nonsurgical MCL treatment.

Is ACL reconstruction a prerequisite for the patients having recreational sporting activities?

OBJECTIVE

Whether surgical or conservative treatment is more effective in allowing patients to return to physical activity after anterior cruciate ligament (ACL) injury is controversial. We sought to compare mid-term outcome measures between isolated ACL tear patients who underwent reconstruction followed by closed kinetic chain exercises and those who underwent neuromuscular training only.

METHODS

We retrospectively evaluated patients with ACL tears who underwent post-surgery CKC strength training after ACL reconstruction (Group A), and patients who only underwent neuromuscular training (Group B) with a minimum follow-up time of 5 years. Surgical techniques, rehabilitation, assessment of subjective knee function, one-leg hop test, assessment of joint position sense, muscle strength, and the health profile of the patient were evaluated.

RESULTS

Overall, 43 patients were included in Group A (mean age, 32.56 ± 4.89; Tegner activity scale, 5) and 39 patients in Group B (31.67 ± 7.27; 5). Patients in both groups returned to their regular physical activity level after a similar time frame (Group A: average, 12 months; Group B, average, 13.4 months). The mean Lysholm knee score was 88.52 ± 7.65 in Group A and 86.21 ± 13.72 in Group B. Mean distances for the one-leg hop test for Group A were 135.21 ± 31.66 and 145.36 ± 42.10 mm in the reconstructed and uninjured knees, respectively. In Group B, the mean hop distances were 132.47 ± 28.13 and 147.89 ± 21.45 mm in the rehabilitated and uninjured knees, respectively. No statistical difference was observed between the groups for any of the parameters evaluated, including assessment of subjective knee function, one-leg hop test, assessment of joint position sense, muscle strength, and the health profile.

CONCLUSION

Our data suggest that early surgical reconstruction may not be a prerequisite to returning to recreational physical activities after injury in patients with ACL tears.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Positive effects of an extracellular matrix hydrogel on rat anterior cruciate ligament fibroblast proliferation and collagen mRNA expression

Background/Objective

We have previously shown that an extracellular matrix (ECM) bioscaffold derived from porcine small intestine submucosa (SIS) enhanced the healing of a gap injury of the medial collateral ligament as well as the central third defect of the patellar tendon. With the addition of a hydrogel form of SIS, we found that a transected goat anterior cruciate ligament (ACL) could also be healed. The result begs the research question of whether SIS hydrogel has positive effects on ACL fibroblasts (ACLFs) and thus facilitates ACL healing.

Methods

In the study, ECM-SIS hydrogel was fabricated from the digestion of decellularised and sterilised sheets of SIS derived from αGal-deficient (GalSafe) pigs. As a comparison, a pure collagen hydrogel was also fabricated from commercial collagen type I solution. The morphometrics of hydrogels was assessed with scanning electron microscopy. The ECM-SIS and collagen hydrogels had similar fibre diameters (0.105 ± 0.010 μm vs. 0.114 ± 0.004 μm), fibre orientation (0.51 ± 0.02 vs. 0.52 ± 0.02), and pore size (0.092 ± 0.012 μm vs. 0.087 ± 0.008 μm). The preservation of bioactive properties of SIS hydrogel was assessed by detecting bioactive molecules sensitive to processing and enzyme digestion, such as growth factors fibroblast growth factor-2 (FGF-2) and transforming growth factor-beta 1 (TGF-β1), with enzyme-linked immunosorbent assay. ACLFs were isolated and expanded in culture from explants of rat ACLs (n = 3). The cells were then seeded on the hydrogels and cultured with 0%, 1%, and 10% foetal bovine serum (FBS) for 3 days and 7 days. Cell attachment was observed using a light microscope and scanning electron microscopy, whereas cell proliferation and matrix production (collagen types I and III) were examined with bromodeoxyuridine assays and reverse transcription-polymerase chain reaction, respectively.

Results

The results showed that FGF-2 and TGF-β1 in the SIS hydrogel were preserved by 50% (65.9 ± 26.1 ng/g dry SIS) and 90% (4.4 ± 0.6 ng/g dry SIS) relative to their contents in ECM-SIS sheets, respectively. At Day 3 of culture, ACLFs on the SIS hydrogel were found to proliferate 39%, 31%, and 22% more than those on the pure collagen hydrogel at 0%, 1%, and 10% FBS, respectively (p < 0.05). Collagen type I mRNA expression was increased by 150%, 207%, and 100%, respectively, compared to collagen hydrogel (p < 0.05), whereas collagen type III mRNA expression was increased by 123% and 132% at 0% and 1% FBS, respectively (all p < 0.05) but not at 10% FBS. By Day 7, collagen type I mRNA expression was still elevated by 137% and 100% compared to collagen hydrogel at 1% and 10% FBS, respectively (p < 0.05). Yet, collagen type III mRNA levels were not significantly different between the two groups at any FBS concentrations.

Conclusion

Our data showed that the ECM-SIS hydrogel not only supported the growth of ACLFs, but also promoted their proliferation and matrix production relative to a pure collagen hydrogel. As such, ECM-SIS hydrogel has potential therapeutic value to facilitate ACL healing at the early stage after injury.

Graft failure versus graft fixation in ACL reconstruction: histological and immunohistochemical studies in rabbits

The causes of graft failure after anterior cruciate ligament (ACL) reconstruction are multifactorial including the methods of graft fixation. The purpose of this study was to examine the ACL graft failure in three different methods of graft fixations including interference screw fixation, suture-post fixation and combined interference screw and suture-post fixation. We hypothesized that the fixation method after ACL reconstruction can affect the graft healing in tibial tunnel. Eighteen New Zealand white rabbits were categorized into three groups according to the method of fixation in unilateral ACL reconstruction with long digital extensor autograft. Histological examination demonstrated that the combined fixation and suture-post fixation groups showed significantly better integration between tendon and bone (P = 0.04). In immunohistochemical analysis, the combined fixation and suture-post fixation groups showed significantly higher BMP-2 and VEGF expressions than interference screw (P < 0.01). The tendon-bone healing after ACL reconstruction was affected by the method of graft fixation. Combined fixation with interference screw and suture-post reduced graft-tunnel micromotion and improved the graft healing in tibial tunnel.

Management of the athlete with acute anterior cruciate ligament deficiency

Background:

Identification of highly active individuals early after acute anterior cruciate ligament deficiency who are good candidates for nonoperative management is a clinical challenge. The University of Delaware has developed and validated a treatment algorithm and screening examination to distinguish between nonoperative and surgical candidates.

Study Design:

Review.

Evidence Acquisition:

A description of the decision-making rules and rehabilitation protocol for highly active individuals with anterior cruciate ligament deficiency is provided. Results from clinical trials, outcome studies, and biomechanical investigations conducted using the treatment algorithm and screening examination are also reviewed.

Results:

Patients identified as nonoperative rehabilitation candidates using these clinical guidelines have a far greater success rate than what has been reported when patients self-select nonoperative management. Furthermore, nonoperative outcomes are improved when patients participate in a perturbation-enhanced rehabilitation protocol. Divergent lower extremity movement patterns are consistent with the different functional abilities of the dichotomous patient groups identified with the screening examination.

Conclusion:

Given the differential patient response to anterior cruciate ligament injury, implementation of the decision-making guidelines discussed in this review offers clinicians the opportunity to provide individualized patient care rather than continuing with a blanket surgical treatment strategy.

Functional tissue engineering of ligament healing

Ligaments and tendons are dense connective tissues that are important in transmitting forces and facilitate joint articulation in the musculoskeletal system. Their injury frequency is high especially for those that are functional important, like the anterior cruciate ligament (ACL) and medial collateral ligament (MCL) of the knee as well as the glenohumeral ligaments and the rotator cuff tendons of the shoulder. Because the healing responses are different in these ligaments and tendons after injury, the consequences and treatments are tissue- and site-specific. In this review, we will elaborate on the injuries of the knee ligaments as well as using functional tissue engineering (FTE) approaches to improve their healing. Specifically, the ACL of knee has limited capability to heal, and results of non-surgical management of its midsubstance rupture have been poor. Consequently, surgical reconstruction of the ACL is regularly performed to gain knee stability. However, the long-term results are not satisfactory besides the numerous complications accompanied with the surgeries. With the rapid development of FTE, there is a renewed interest in revisiting ACL healing. Approaches such as using growth factors, stem cells and scaffolds have been widely investigated. In this article, the biology of normal and healing ligaments is first reviewed, followed by a discussion on the issues related to the treatment of ACL injuries. Afterwards, current promising FTE methods are presented for the treatment of ligament injuries, including the use of growth factors, gene delivery, and cell therapy with a particular emphasis on the use of ECM bioscaffolds. The challenging areas are listed in the future direction that suggests where collection of energy could be placed in order to restore the injured ligaments and tendons structurally and functionally.

Management of combined ACL-MCL tears: a systematic review

INTRODUCTION

The optimal management for combined anterior cruciate ligament-medial collateral ligament (ACL-MCL) injuries is controversial.

SOURCES OF DATA

We performed a literature search using Medline, Cochrane and Google Scholar using the keywords: 'ACL' and 'MCL' in combination with 'surgery treatment', 'conservative treatment', 'surgery management', 'conservative management', 'surgical treatment' and 'surgical management'. We identified 23 published studies.

AREAS OF AGREEMENT

Conservative and surgical management for combined ACL-MCL injuries resulted in different functional outcomes. The Coleman Methodology Score showed great heterogeneity in terms of study design, patient characteristics, management methods and outcome assessment and generally low methodological quality.

AREAS OF CONTROVERSY

Given the heterogeneity in terms of treatment and results, we did not find a univocal trend over the years regarding MCL management (conservative or surgical). The use of several scoring systems did not allow us to compare outcomes in the different studies.

GROWING POINTS

There is a need for a common validated scale for clinical measurements for ACL-MCL injuries, so as to allow easier and more reliable comparison of outcomes in different studies. To improve diagnostic certainty of combined ACL-MCL injuries, all patients should have imaging assessment (MR and stress-radiography) in addition to clinical examination.

AREAS TIMELY FOR DEVELOPING RESEARCH

There is a need to perform appropriately powered randomized clinical trials of conservative and surgical treatment of combined ACL-MCL injuries, using standard diagnostic assessment, common and validated scoring system comparing reported outcomes and duration of follow-up more than 2 years.

Isokinetic Dynamometry in Anterior Cruciate Ligament Injury and Reconstruction

The use of isokinetic dynamometry has often been criticised based on the face-validity argument that isokinetic movements poorly resemble the everyday multi-segmented, dynamic activities of human movements. In the anterior cruciate ligament (ACL) reconstruction or deficiency population where muscle deficits are ubiquitous, this review paper has made a case for using isokinetic dynamometry to isolate and quantify these deficits in a safe and controlled manner. More importantly, the usefulness of isokinetic dynamometry, as applied in individuals with ACL reconstruction or deficiency, is attested by its established known-group and convergent validity. Known-group validity is demonstrated by the extent to which a given isokinetic measure is able to identify individuals who could and could not resume pre-morbid athletic or strenuous activities with minimal functional limitations following an ACL injury. Convergent validity is demonstrated by the extent to which a given isokinetic measure closely associates with self-report measures of knee function in individuals with ACL reconstruction. A basic understanding of the measurement properties of isokinetic dynamometry will guide the clinicians in providing reasoned interventions and advancing the clinical care of their clients. Key words: Biomechanics, Knee, Validity

A 10-year prospective trial of a patient management algorithm and screening examination for highly active individuals with anterior cruciate ligament injury: Part 1, outcomes

BACKGROUND

A treatment algorithm and screening examination have been developed to guide patient management and prospectively determine potential for highly active individuals to succeed with nonoperative care after anterior cruciate ligament rupture.

OBJECTIVE

To prospectively characterize and classify the entire population of highly active individuals over a 10-year period and provide final outcomes for individuals who elected nonoperative care.

METHODS

Inclusion criteria included presentation within 7 months of the index injury and an International Knee Documentation Committee level I or II activity level before injury. Concomitant injury, unresolved impairments, and a screening examination were used as criteria to guide management and classify individuals as noncopers (poor potential) or potential copers (good potential) for nonoperative care.

RESULTS

A total of 832 highly active patients with subacute anterior cruciate ligament tears were seen over the 10-year period; 315 had concomitant injuries, 87 had unresolved impairments, and 85 did not participate in the classification algorithm. The remaining 345 patients (216 men, 129 women) participated in the screening examination a mean of 6 weeks after the index injury. There were 199 subjects classified as noncopers and 146 as potential copers. Sixty-three of 88 potential copers successfully returned to preinjury activities without surgery, with 25 of these patients not undergoing anterior cruciate ligament reconstruction at the time of follow-up.

CONCLUSION

The classification algorithm is an effective tool for prospectively identifying individuals early after anterior cruciate ligament injury who want to pursue nonoperative care or must delay surgical intervention and have good potential to do so.

A 10-year prospective trial of a patient management algorithm and screening examination for highly active individuals with anterior cruciate ligament injury: Part 2, determinants of dynamic knee stability

OBJECTIVE

To clarify the determinants of dynamic knee stability early after anterior cruciate ligament injury.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 1.

METHODS

Three hundred forty-five consecutive patients who were regular participants in International Knee Documentation Committee level I/II sports before injury and had an acute isolated anterior cruciate ligament injury from the practice of a single orthopaedic surgeon underwent a screening examination including clinical measures, knee laxity, quadriceps strength, hop testing, and patient self-reported knee function a mean of 6 weeks after injury when impairments were resolved. Independent t tests were performed to evaluate differences in quadriceps strength and anterior knee laxity between potential copers and noncopers. Hierarchical regression was performed to determine the influence of quadriceps strength, preinjury activity level, and anterior knee laxity on hop test performance, as well as the influence of timed hop, crossover hop, quadriceps strength, preinjury activity level, and anterior knee laxity on self-assessed global function.

RESULTS

Neither anterior knee laxity nor quadriceps strength differed between potential copers and noncopers. Quadriceps strength influenced hop test performance more significantly than did preinjury activity level or anterior knee laxity, but the variance accounted for by quadriceps strength was low (range, 4%-8%). Timed hop performance was the only variable that affected self-assessed global function.

CONCLUSION

Traditional surgical decision making based on passive anterior knee laxity and preinjury activity level is not supported by the results, as neither is a good predictor of dynamic knee stability. A battery of clinical tests that capture neuromuscular adaptations, including the timed hop test, may be useful in predicting function and guiding individualized patient management after anterior cruciate ligament injury.

Cyclic loading causes faster rupture and strain rate than static loading in medial collateral ligament at high stress

BACKGROUND

Ligaments may be subjected to higher than normal loads when one of the complementary ligament restraints of a joint or the ligament itself is injured. Damage can accumulate in a ligament due to cyclic and static loading under these increased loads, but it remains unknown whether one type of loading will cause rupture faster than the other in medial collateral ligament.

METHODS

The objective of this study was to compare the time and strain behaviour of normal rabbit medial collateral ligaments under static and cyclic loading over a wide range of applied stresses, with particular emphasis on time-to-rupture. Stresses were normalized to ultimate tensile strength and selected from three regions of the stress-strain curve: two linear-region stresses (60% and 30% of the ultimate tensile strength) and one stress at the transition from the toe-region to the linear-region (15% of the ultimate tensile strength).

FINDINGS

Cyclic loading caused faster rupture than static loading at all stresses. Strain-time profiles were different in that the increase in strain (strain relative to initial strain) was greater under static than cyclic loading prior to rupture. However, steady-state strain rate (when increase in strain reaches a plateau in the secondary strain stage) was greater under cyclic than static loading.

INTERPRETATIONS

These results suggest that cyclic loading is more detrimental than static loading in ligaments that are subjected to higher than normal stresses following injury of a complementary restraint or the ligament itself.

Leg kinematics and kinetics in landing from a single-leg hop for distance. A comparison between dominant and non-dominant leg

BACKGROUND

Anterior cruciate ligament (ACL) deficiency can be a major problem for athletes and subsequent reconstruction of the ACL may be indicated if a conservative regimen has failed. After ACL reconstruction signs of abnormality in the use of the leg remain for a long time. It is expected that the landing after a single-leg hop for distance (horizontal hop) might give insight in the differences in kinematics and kinetics between uninjured legs and ACL-reconstructed legs. Before the ACL-reconstructed leg can be compared with the contralateral leg, knowledge of differences between legs of uninjured subjects is needed.

METHODS

Kinematic and kinetic variables of both legs were measured with an optoelectronic system and a force plate and calculated by inverse dynamics. The dominant leg (the leg with biggest horizontal hop distance) and the contralateral leg of nine uninjured subjects were compared.

FINDINGS

No significant differences were found in most of the kinematic and kinetic variables between dominant leg and contralateral leg of uninjured subjects. Only hop distance and hip extension angles differed significantly.

INTERPRETATION

This study suggests that there are no important differences between dominant leg and contralateral leg in healthy subjects. As a consequence, the uninvolved leg of ACL-reconstructed patients can be used as a reference. The observed variables of this study can be used as a reference of normal values and normal differences between legs in healthy subjects.

Intraarticular stabilization after anterior cruciate ligament tear in children and adolescents: results 6 years after surgery

Tear of the anterior cruciate ligament (ACL) secondary to knee sprain injury is also quite common among children and adolescents. Whether reconstruction is indicated and which technique should be employed is still controversial. The debate focuses on the possible risk of growth plate damages due to intraarticular operative reconstruction techniques. For more details on benefit and risks of operative stabilization, our clinic's large number of surgical results was to be evaluated retrospectively. In a total of 437 knee joint arthroscopies performed between 1982 and 1992 in children and adolescents with open physes, aged 3-16 years, 63 surgical repair/reconstructions according to an algorithm were carried out. The average age at surgery was 13.8 years. Follow-up an average 6.5 years after the operation consisted of clinical and radiological examination, Lysholm, Tegner, and IKDC scores. This report focuses on intraarticular ligament reconstruction methods. Forty-four patients could be followed up, comprising of five reinsertions, ten internal fixations, 15 cases semitendinosus tendon (ST) augmentations, and 14 primary reconstructions with the middle one-third of the patellar tendon (PT). In every ST and PT case, transtibial and transfemoral tunnels were drilled. The clinical stability examination was supplemented by KT-1000 arthrometer measurements and radiography in two planes. Averaged for all surgical techniques, good and very good results were obtained in over 75% of cases. There were no major growth defects and rarely signs of osteoarthrosis. According to literature, conservative treatment of ACL tears and even primary ACL repair is not infrequently followed by re-ruptures. Therefore, reconstruction is the preferred procedure for patients aged 12 years or more. As most authors hesitate to possibly block the physes by obtaining and anchoring patellar tendon grafts, the ST should be preferred. This study demonstrates in a large number of ACL stabilizations, despite transepiphyseal drilling and grafting, very good stabilization is achieved, but no growth defects have to be expected.

Biomechanical evidence supporting a differential response to acute ACL injury

OBJECTIVE

To describe movement patterns in people with complete anterior cruciate ligament rupture objectively identified as good candidates for non-operative management of the injury.

DESIGN

Involved side kinematics and kinetics were compared to the uninvolved side and to uninjured subjects.

BACKGROUND

High-level athletes with anterior cruciate ligament rupture and poor dynamic stability (non-copers) have movement alterations, including less knee flexion and a decreased internal knee extensor moment during loading response, that are not seen in those with excellent knee stability (copers). Our screening exam can identify people with good rehabilitation potential for non-operative management of anterior cruciate ligament injury (potential copers), but the movement strategies of these individuals are unknown.

METHODS

Sagittal plane kinematics and kinetics during the stance phase of walking and jogging were collected from 11 subjects who had an acute anterior cruciate ligament rupture and met the criteria of the screening exam, and were compared to 10 uninjured subjects, who we studied previously. Variables were those in which non-copers differed from uninjured subjects.

RESULTS

The potential copers flexed their involved knee less than uninjured subjects and their uninvolved side during walking. Potential copers, compared to uninjured subjects, also had a lower vertical ground reaction force during loading response, a lower knee support moment, and an increased ankle support moment during walking. In jogging, the involved knee angle at initial contact was more extended compared to uninjured subjects, and the amount of knee flexion was less than the uninvolved side. No differences in kinetics were present during jogging.

CONCLUSIONS

This study provides evidence that the potential copers identified by the screening examination have movement patterns that are consistent with people who have more knee stability than non-copers.

RELEVANCE

Although potential copers have developed some characteristics of a successful stabilization strategy, the presence of kinematic alterations indicates that they may benefit from training programs designed to enhance dynamic knee stability.

Proposed practice guidelines for nonoperative anterior cruciate ligament rehabilitation of physically active individuals

Nonoperative management of anterior cruciate ligament (ACL) rupture has not been a successful option for those who participate in high-level physical activity. However, there are instances when patients may want to attempt to return to physically demanding activities with nonoperative rehabilitation for an ACL injury. The purpose of this commentary is to describe guidelines for nonoperative management of physically active individuals with ACL injuries who wish to return to preinjury levels of physical activity. The guidelines are based on the results of 2 clinical studies that improved the overall success of nonoperative management of physically active individuals with ACL ruptures. A decision-making process for selecting appropriate candidates for nonoperative management (rehabilitation candidates) is described. Individuals are classified as rehabilitation candidates if they have no concomitant ligament or mensical damage associated with the ACL injury, have a unilateral ACL injury, and meet all 4 of the following criteria: (1) timed hop test score of 80% or more of the uninjured limb, (2) Knee Outcome Survey Activities of Daily Living Scale score of 80% or more, (3) global rating of knee function of 60% or more, and (4) no more than 1 episode of giving way since the incident injury to the time of testing. Individuals meeting the criteria of a rehabilitation candidate undergo an intensive rehabilitation program before returning to high-level activity. The rehabilitation program consisting of lower extremity muscle strength training, cardiovascular endurance training, agility and sport-specific skill training, and a training program using balance perturbations is described.

The Efficacy of Perturbation Training in Nonoperative Anterior Cruciate Ligament Rehabilitation Programs for Physically Active Individuals

Background and Purpose. Treatment techniques involving perturbations of support surfaces may induce compensatory muscle activity that could improve knee stability and increase the likelihood of returning patients to high-level physical activity. The purpose of this study was to determine the efficacy of augmenting standard nonoperative anterior cruciate ligament (ACL) rehabilitation programs with a perturbation training program. Subjects. Twenty-six patients with an acute ACL injury or ruptures of ACL grafts participated in the study. Subjects had to have a unilateral ACL injury, be free of concomitant multiple ligament or meniscal damage requiring surgical repair, and pass a screening examination designed to identify patients who had the potential to return to high-level physical activity with nonoperative treatments. Subjects also had to be regular participants in level I activities (eg, soccer, football, basketball) or level II activities (eg, racquet sports, skiing, construction work). Methods. Subjects were randomly assigned to either a group that received a standard rehabilitation program (standard group) or a group that received the standard program augmented with a perturbation training program (perturbation group). Treatment outcome was determined from scores on the Knee Outcome Survey's Activities of Daily Living Scale (ADLS) and Sports Activity Scale, a global rating of knee function, scores on a series of single-limb hop tests, measurements of maximum isometric quadriceps femoris muscle force output, and the group frequency of unsuccessful rehabilitation. Unsuccessful rehabilitation was defined as the occurrence of an episode of giving way of the knee or failure to maintain the functional status of a rehabilitation candidate on retesting. Results. More subjects had unsuccessful rehabilitation in the standard group compared with the perturbation group. There was a within-group × time interaction for the ADLS, global rating of knee function, and crossover hop test scores. These scores decreased from posttraining to the 6-month follow-up for the standard group. Conclusion and Discussion. Although both the standard program and the perturbation training program may allow subjects to return to high-level physical activity, the perturbation training program appears to reduce the risk of continued episodes of giving way of the knee during athletic participation, and it allows subjects to maintain their functional status for longer periods.

Laxity, instability, and functional outcome after ACL injury: copers versus noncopers

PURPOSE

The purpose of this study was to determine the relationship among laxity, quadriceps strength, instability, and function in subjects with complete rupture of the anterior cruciate ligament (ACL) who compensate well for the injury (copers) and those who require surgical stabilization (noncopers).

METHODS

Forty-five patients with unilateral ACL rupture (confirmed via arthroscopy or magnetic resonance imaging (MRI) and arthrometer measurements) participated in this study. Subjects were divided into two groups: copers (N = 12), and subacute noncopers (N = 18) and chronic noncopers (N = 15). All copers had returned to all preinjury activity (including index sport) without limitation. Maximum manual anterior tibiofemoral laxity measurements, quadriceps femoris muscle strength measurements, and a series of hop tests were performed. Lysholm Scale, Knee Outcome Survey (KOS), global rating of knee function, and the International Knee Documentation Committee (IKDC) form were completed.

RESULTS

There was no significant difference in laxity between copers (X = 5.5+/-2.7 mm) and noncopers (chronic, X = 5.1+/-2.8 mm and subacute, X = 4.2+/-2.2 mm) or in IKDC scores among the groups. The copers, however, scored significantly better than the chronic and subacute ACL-deficient subsets on all other measures. Measurements of laxity were not correlated to any functional outcome measure or to episodes of instability.

CONCLUSIONS

Copers were not different in any meaningful way from the noncopers before injury, had equal or greater side-to-side laxity differences, and functioned normally. A battery of tests was identified that accurately discriminated noncopers from copers even early after injury. Thus, measurements of laxity alone are insufficient for determining functional status after ACL injury.

The relationship between passive joint laxity and functional outcome after anterior cruciate ligament injury

Twenty patients with anterior cruciate ligament-deficient knees were studied. Ten patients returned to all sports activities (compensators) and 10 patients were not improved with nonoperative management and required surgical stabilization (noncompensators). Joint laxity was measured using a KT-2000 arthrometer (manual maximum Lachman). Subjects completed a Lysholm questionnaire and Knee Outcome Score. The International Knee Documentation Committee form was also completed. Patients also rated their knee function on a scale of 1 to 100. There was no difference in level and frequency of athletic activity between the two groups before their anterior cruciate ligament injuries as determined by the knee outcome score. The compensator group had a mean side-to-side difference of 3.25 mm at 89 N and the noncompensators had a mean difference of 3 mm preoperatively. Manual maximum tests gave side-to-side differences of 6.7 mm for the compensators and 6 mm for the noncompensators. There were no differences in laxity measures between groups. The correlation between knee outcome scores and side-to-side laxity measurements were not significant. Measurements of anterior laxity in anterior cruciate ligament-deficient patients were not correlated with measures of functional outcome used in this study. Functional outcome measurements that are partially based on joint laxity measures, such as the International Knee Documentation Committee form, may artificially overestimate the disability after anterior cruciate ligament rupture.

Biomechanics of patellar tendon autograft for reconstruction of the anterior cruciate ligament in the goat: three-year study

This study examined the biomechanics of anterior cruciate ligament-patellar tendon autografts for as long as 3 years after surgery. Twenty-seven adult female goats were tested; four served as controls and the others received an autograft to the right knee with each left knee serving as an additional control. The animals with grafts were tested at 0 week (n = 4), 6 weeks (n = 4), 12 weeks (n = 4), 24 weeks (n = 3), 1 year (n = 5), and 3 years (n = 3) after surgery. The anteroposterior laxity of the knee joint, load-relaxation, and structural and material properties of the graft were tested. The anteroposterior laxity was significantly greater than that of the controls for all groups except at 3 years. Load-relaxation was greater than that of the control anterior cruciate ligaments, but in the 1 and 3-year grafts load-relaxation was less than that of the patellar tendons with 5 minutes of sustained loading. Between 12 and 52 weeks, the stiffness and modulus of the grafts increased 3-fold, but the improvement was slow afterward. At 3 years, the strength and stiffness of the grafts were 44 and 49% those of the control ligaments, respectively; the modulus was 37 and 46% that of the control anterior cruciate ligaments and patellar tendons, respectively. The persistent inferior mechanical performance at 3 years suggests that anterior cruciate ligament grafts may never attain normal strength.

Anterior cruciate ligament suture in comparison with plasty. A 5-year follow-up study

In this retrospective study we analyse the results of primary anterior cruciate ligament (ACL) sutures, primary ACL plasties and secondary ACL plasties 5 years after operation. All operations were performed with an additional PDS augmentation. Follow-ups of 100 of 130 patients could be done (80 male and 20 female). The average age at time of operation was 29.2 years. ACL rupture in 81 patients occurred due to a sport accident. In 26 patients a primary ACL suture was performed, in 59 patients a primary ACL plasty and in 15 patients an ACL plasty due to instability. There was no difference between the primary and secondary plasty groups, but there was between the suture and the plasty groups. In all, 92% of the suture group and 69% of the plasty group were satisfied with the surgical results. The pivot shift, Lachman and anterior drawer sign were less frequent in the ACL suture group, and the Lysholm score was higher. Primary suture combined with a PDS augmentation seems to represent an adequate treatment of acute proximal ACL ruptures.