Strain on the anterior cruciate ligament during closed kinetic chain exercises

PURPOSE: The purpose of this investigation was to characterize the ACL strains produced during four commonly prescribed CKC exercises; the step-up, the step-down, the lunge, and the one-legged sit to stand. We hypothesized that the ACL strains produced during the lunge and one-legged sit to stand exercises (the exercises that challenge the leg musculature to a greater extent and utilize greater hip flexion) would be less than those produced during the step-up and step-down exercises. METHODS: The strains in the anteromedial bundle of the ACL were measured while nine subjects, who had normal ligaments, performed the four exercises. Peak ACL strain values and the ACL strain patterns as a function of knee flexion angle were compared between exercises. RESULTS: No significant differences were found between the peak ACL strain values (mean +/- SEM) between exercises (step-up: 2.5 +/- 0.36; step-down: 2.6 +/- 0.34; lunge 1.9 +/- 0.50; one-legged sit to stand: 2.8 +/- 0.27). The mean ACL strain values as a function of knee flexion angle were not significantly different. On average, there was a significant increase in ACL strain as the knee was extended for each exercise. CONCLUSIONS: The ACL strain responses produced during these CKC exercises were equal and similar to those produced during other rehabilitation exercises (i.e., squatting, active extension of the knee) previously tested.     

Preoperative quadriceps strength as a predictor of return to sports after anterior cruciate ligament reconstruction in competitive athletes

ObjectivesTo determine whether preoperative quadriceps strength predicts the likelihood of return to sports (RTS) following anterior cruciate ligament reconstruction (ACLR) in competitive athletes.DesignCase-control study.SettingSingle-center.ParticipantsA total of 221 competitive athletes who underwent primary ACLR were followed and divided into RTS (n = 177) and non-RTS (n = 44) groups based on self-reported sports activities at one year postoperatively.Main outcome measuresIsokinetic quadriceps strength tests were performed preoperatively and at six months and one year postoperatively, and the quadriceps index (QI) was calculated. Functional performance was evaluated by the single-leg hop (SLH) test at six months postoperatively.ResultsPreoperative QI significantly predicted the likelihood of RTS (odds ratio, 1.68 per 10-unit increase; P < 0.001), with a preoperative QI cut-off of 66% (AUC: 0.74; sensitivity: 68.9%; specificity: 77.3%). Subjects with a preoperative QI < 66% had a significantly lower postoperative QI, SLH, and rates of RTS compared to those with a higher preoperative QI (P < 0.01).ConclusionsPreoperative quadriceps strength could predict the likelihood of RTS following ACLR, and a preoperative QI < 66% was associated with a greater risk of unsuccessful RTS at one year postoperatively. Preoperative QI should be evaluated as a predictor of RTS.     

A prospective four- to seven-year follow-up after arthroscopic anterior cruciate ligament reconstruction

The aim of this study was to evaluate the results after arthroscopic anterior cruciate ligament reconstruction using a bone-patellar tendon-bone graft in 99 patients, who were followed up prospectively for four to seven years. The pre-injury Tegner activity level was 7 compared with 5 at the four- to seven-year follow-up (P<0.0001). The preoperative Lysholm score was 74.5 points. At the two-year follow-up, the Lysholm score was 95 points, while it was 90 points at the four- to seven-year follow-up (P<0.0001 preoperative vs two years and preoperative vs four to seven years and P<0.0005 two years vs four to seven years). Using the IKDC evaluation system, 80% of the patients were classified as normal or nearly normal and 20% as abnormal or severely abnormal at the final follow-up. The KT-1000 laxity measurements revealed a side-to-side difference of 2.9 mm preoperatively, 0.6 at two years and 1.0 mm at four to seven years. Twenty-six patients underwent additional surgery during the follow-up period. The results after arthroscopic reconstruction of the anterior cruciate ligament appear to be satisfactory both at the short- and the medium-term follow-ups, but there appears to be some deterioration between the two-year and the four- to seven-year follow-up.     

Effects of open versus closed kinetic chain training on knee laxity in the early period after anterior cruciate ligament reconstruction

Knee extensor resistance training using open kinetic chain (OKC) exercise for patients recovering from anterior cruciate ligament reconstruction (ACLR) surgery has lost favour mainly because of research indicating that OKC exercise causes greater ACL strain than closed kinetic chain (CKC) exercise. In this prospective, randomized clinical trial the effects of these two regimes on knee laxity were compared in the early period after ACLR surgery. Thirty-six patients recovering from ACLR surgery (29 males, 7 females; age mean = 30) were tested at 2 and 6 weeks after ACLR with knee laxity measured using the Knee Signature System arthrometer. Between tests subjects trained using either OKC or CKC resistance of their knee and hip extensors in formal physical therapy sessions three times per week. Following adjustment for site of treatment, pretraining injured knee laxity, and untreated knee laxity at post-training, the use of OKC exercise, when compared to CKC exercise, was found to lead to a 9% increase in looseness with a 95% confidence interval of -8% to +29%. These results indicate that the great concern about the safety of OKC knee extensor training in the early period after ACLR surgery may not be well founded.     

Factors affecting return to sports after anterior cruciate ligament reconstruction with patellar tendon and hamstring graft: a prospective clinical investigation

In athletes, anterior cruciate ligament (ACL) reconstruction is recommended after injury to restore the normal knee function and allow subsequent return to sport. Successful ACL reconstruction with patellar tendon (PT) and hamstring tendon (HT) grafts combined with a well-structured rehabilitation program could bring athletes back to their previous level of sport activities. We prospectively followed-up 100 athletes who underwent ACL reconstruction with either PT (n=50) or HT grafts (n=50). Evaluation was done pre-operatively and post-operatively (3, 6, 12, and 24 months) using International Knee Documentation Committee (IKDC), Lysholm, Noyes, and Tegner scales. Subjective assessment numeric evaluation (SANE), knee activity rating scale (Marx) and a psychological profile questionnaire (psychovitality) were also utilized. Objective evaluations included isokinetic tests and computerized knee motion analysis. Data gathered were statistically analyzed using the Mann–Whitney non-parametric U-test. Among the 100 patients who have undergone ACL reconstruction, 65% returned to the same level of sports, 24% changed sports and 11% ceased sport activities. No significant difference (P>0.05) in outcome between PT and HT grafts were observed. No significant differences (P>0.05) were noted between athletes who “returned” to their previous sport and those who “did not return” to sports at the same level when using the IKDC, Lysholm, Noyes, and Tegner knee evaluation scales. However, significant difference was observed with the knee scores obtained by those who returned and those who completely ceased participation in sport activities. Computerized laxity test revealed that 90% of these patients have less than 3 mm side-to-side difference with no significant difference between HT and PT groups. Patients who “returned to sports” obtained significantly better scores with the Marx scale (P=0.001) and the psychovitality questionnaire (P=0.001) than those who did not. Conventional knee scales including IKDC, Lysholm, Noyes, and Tegner remain as reliable means of evaluating outcome of ACL reconstruction. However, the data obtained from these are not sufficient to determine which among the patients who had knee reconstruction can successfully return to sport. The use of the Marx knee activity rating scale and the evaluation of the athletes’ psychological profile are additional scales that can be useful in determining which among the patients treated have a better chance of returning to their pre-injury activity levels.     

Cognitive-behavioral-based physical therapy to enhance return to sport after anterior cruciate ligament reconstruction: An open pilot study

ObjectivesTo describe feasibility, adherence, acceptability, and outcomes of a cognitive-behavioral-based physical therapy (CBPT-ACLR) intervention for improving postoperative recovery after anterior cruciate ligament reconstruction (ACLR).DesignPilot study.SettingAcademic medical center.ParticipantsEight patients (mean age [SD] = 20.1 [2.6] years, 6 females) participated in a 7-session telephone-based CBPT-ACLR intervention beginning preoperatively and lasting 8 weeks after surgery.Main outcome measuresAt 6 months, patients completed Knee Injury and Osteoarthritis Outcome Score (KOOS) sports/recreation and quality of life (QOL) subscales, International Knee Documentation Committee (IKDC), Tampa Scale of Kinesiophobia (TSK), Pain Catastrophizing Scale (PCS), and Knee Self-Efficacy Scale (K-SES), return to sport (Subjective Patient Outcome for Return to Sports), and satisfaction. Minimal clinically important difference (MCID) was used for meaningful change.ResultsSeven (88%) patients completed all sessions. Seven (88%) patients exceeded MCID on the TSK, 6 (75%) on the PCS, 5 (63%) on the KOOS sports/recreation subscale, 4 (50%) on the IKDC, and 3 (38%) on the KOOS QOL subscale. Three (38%) patients returned to their same sport at the same level of effort and performance. All patients were satisfied with their recovery.ConclusionsA CBPT-ACLR program is feasible and acceptable for addressing psychological risk factors after ACLR.     

Knee brace after bone-tendon-bone anterior cruciate ligament reconstruction Randomized, prospective study with 2-year follow-up

In a prospective study 60 patients were randomized to brace and no-brace groups after bone-tendon-bone anterior cruciate ligament reconstruction. The brace group wore a rehabilitation orthosis for 12 weeks postoperatively, while the no-brace group was mobilized immediately, and crutches were discarded 2 weeks postoperatively. The groups were comparable with respect to age, gender, time from injury to surgery, knee score (Lysholm), activity level (Tegner), degree of laxity and isokinetic muscle torque. Although compared with the preoperative situation patients in both groups had significantly improved, there were no differences between the groups 1 and 2 years postoperatively in terms of functional outcome (Lysholm and Tegner scores), stability of the knee or isokinetic muscle torque. Received: 13 June 1996 Accepted: 23 November 1996     

Prevention of permanent arthrofibrosis after anterior cruciate ligament reconstruction alone or combined with associated procedures: a prospective study in 443 knees

We prospectively determined the effectiveness of an immediate knee motion and early intervention program to prevent permanent motion limitations in a consecutive series of patients who had anterior cruciate ligament autogenous patellar tendon reconstruction for isolated rupture (219 knees) or combined with other procedures (224 knees). The subjects were placed into either a progressive or delayed rehabilitation program and were followed for at least 12 months postoperatively. At follow-up a normal range of motion (0° to at least 135°) was found in 436 knees (98%), and mild losses of extension (–5°) were found in 7 knees. Twenty-three knees (5%) required interventions; 9 had extension casts, 9 had gentle manipulations under anesthesia, 3 had arthroscopic débridements, and 2 had continuous epidural anesthetic and inpatient therapy. All of these 23 knees regained full motion. The 7 patients with mild losses of extension had refused treatment intervention. The 0% incidence rate of permanent arthrofibrosis, and 0.7% reoperation rate for knee motion limitations, demonstrated the effectiveness of our program. Received: 6 December 1999 Accepted: 20 April 2000     

Changes in bone scans after anterior cruciate ligament reconstruction: a prospective study

BACKGROUND: Whether anterior cruciate ligament reconstruction retards the progression of osteoarthrosis is not established. Bone scintigraphy can be useful for monitoring the course of osteoarthrosis. Bone scan findings are abnormal in the majority of patients with anterior cruciate ligament deficiency. Three uptake patterns can be distinguished. HYPOTHESIS: Reconstruction corrects the three abnormal bone scan patterns seen in patients with anterior cruciate ligament deficiency. STUDY DESIGN: Prospective cohort study. METHODS: We performed bone scintigraphy in 80 patients, before and 2 years after anterior cruciate ligament reconstruction. RESULTS: Reconstruction consistently corrected type 2 bone scan pattern (meniscus scan) but not type 1 and 3 patterns (osteoarthrosis and cartilage ulcer scan). Correction of all three patterns decreased among patients who had longer duration of anterior cruciate ligament deficiency and was more reliable for the combined uptake of all three patterns among patients who had less than 6 months of deficiency. CONCLUSION: These findings indicate anterior cruciate ligament reconstruction protects the menisci. Reconstruction may be best performed within 6 months after injury.     

Early versus late start of open kinetic chain quadriceps exercises after ACL reconstruction with patellar tendon or hamstring grafts: a prospective randomized outcome study

The purpose of the present investigation was to evaluate physical outcome after anterior cruciate ligament (ACL) reconstruction with early versus late initiation of open kinetic chain (OKC) exercises for the quadriceps in patients operated on either patellar tendon or hamstring grafts. Sixty-eight patients, 36 males and 32 females, with either patellar tendon graft (34 patients) or hamstring graft (34 patients) were enrolled in this study. All patients were randomly allocated to either early (the 4th postoperative week) or late (the 12th postoperative week) start of OKC exercises for the quadriceps, resulting in four subgroups: patellar tendon reconstruction, early start (P4) or late start (P12) of OKC quadriceps exercises, hamstring tendon reconstruction, early start (H4) or late start (H12) of quadriceps OKC exercises. Prior to surgery and 3, 5 and 7 months later, assessments of range of motion (goniometer), anterior knee laxity (KT-1000), postural sway (KAT 2000), thigh muscle torques (Kin–Com dynamometer) and anterior knee pain (anterior knee pain score) were evaluated. No significant group differences were found in terms of range of motion 3, 5 and 7 months postoperatively. The H4 group showed a significantly higher mean difference of laxity over time of 1.0 mm (CI: 0.18–1.86) than the P4 group (P = 0.04). Within the same type of surgery, the H4 against the H12, the mean difference over time was 1.2 mm (0.37–2.1) higher in the H4 group than in the H12 group (P = 0.01). There were no significant group differences in terms of postural sway or anterior knee pain at the different test occasions. Significant differences in trends (changes over time) were found when comparing the four groups, for both quadriceps muscle torques (P < 0.001) and hamstring muscle torques (P < 0.001). All groups, except the P4 group, reached preoperative values of quadriceps muscle torques at the 7 months follow-up. In the H4 and the H12 groups, significantly lower hamstring muscle torques at the 7 months follow-up compared with preoperative values were found. In conclusion, early start of OKC quadriceps exercises after hamstring ACL reconstruction resulted in significantly increased anterior knee laxity in comparison with both late start and with early and late start after bone–patellar tendon–bone ACL reconstruction. Furthermore, the early introduction of OKC exercises for quadriceps did not influence quadriceps muscle torques neither in patients operated on patellar tendon nor hamstring tendon grafts. On the contrary, it appears as if the choice of graft affected the strength of the specific muscle more than the type of exercises performed. Our results could not determine the appropriate time for starting OKC quadriceps exercises for patients who have undergone ACL reconstruction with hamstring tendon graft. Future studies of long-term results of anterior knee laxity and functional outcome are needed.     

Low rates of patients meeting return to sport criteria 9 months after anterior cruciate ligament reconstruction: a prospective longitudinal study

Purpose

The purpose of the current prospective study was to assess the changes over time in patients tested at 6 months and 9 months after anterior cruciate ligament reconstruction (ACLR) with a return to sport (RTS) test battery. It was hypothesized that more patients passed RTS criteria at 9 months compared to 6 months.

Methods

Sixty-two ACLR patients performed a test battery at an average of 6.5?±?0.7 and 9.5?±?0.9 months after ACLR. All patients underwent a standardized rehabilitation protocol. The test battery consisted of the following tests: a jump-landing task assessed with the Landing Error Scoring System (LESS), three single-leg hop tasks (single-leg hop test, triple-leg hop test, side hop test), isokinetic quadriceps and hamstring strength at 60, 180 and 300°/s and two questionnaires (IKDC and ACL–RSI). Cut off criteria were set as Limb Symmetry Index (LSI)?>?90% (for isokinetic strength and for single-leg hop tasks), LESS?<?5, IKDC score within 15th percentage of healthy subjects and ACL–RSI?>?56 respectively.

Results

At 6 months, two patients (3.2%) passed all criteria. At 9 months, seven patients (11.3%) passed all criteria. Patients improved in all RTS criteria over time except for the IKDC score. Twenty-nine patients (46.8%) did not pass the strength criterion at 60°/s at 9 months after ACLR.

Conclusions

The percentages of patients passing all RTS criteria were low at both 6 and 9 months after ACLR. Quadriceps strength revealed persistent deficits and the lack of improvement in the IKDC score questionnaires shows insufficient self-reported knee function for RTS.

Level of evidence

III.

     

Altered postural sway persists after anterior cruciate ligament reconstruction and return to sport

Postural sway is defined as the movement of a body's center of mass within the base of support to maintain postural equilibrium. Deficits in postural sway are present after ACL injury; however, current evidence linking it to future injury risk is unclear. The purpose of this study was to determine if postural sway deficits persist after ACL reconstruction (ACLR). The hypothesis tested was that after ACLR, patients who return to sport (RTS) would demonstrate differences in postural sway compared to control (CTRL) subjects. Fifty-six subjects with unilateral ACLR released to RTS, and 42 uninjured CTRL subjects participated. Dynamic postural sway was assessed and 3-way (2 × 2 × 2) ANOVA was used to analyze the variables. A side × group × sex (p = 0.044) interaction in postural sway was observed. A side × group analysis also revealed an interaction (p = 0.04) however, no effect of sex was observed (p = 0.23). Analysis within the ACLR cohort showed less (p = 0.001) postural sway on the involved side (1.82 ± 0.84°) versus the uninvolved side (2.07 ± 0.96°). No side-to-side differences (p = 0.73) were observed in the CTRL group. The involved limb of subjects after ACLR demonstrated the least postural sway. In conclusion, these findings indicate that dynamic postural sway may be significantly altered in a population of athletes after ACLR and RTS compared to CTRL subjects. Further investigation is needed to determine if deficits in postural sway can be used as an effective criterion to assist in the decision to safely RTS after ACLR.     

Open and closed kinetic chain exercises in the early period after anterior cruciate ligament reconstruction. Improvements in level walking, stair ascent, and stair descent

Thirty-seven patients who had undergone anterior cruciate ligament reconstruction were tested in a gait analysis laboratory at 2 and 6 weeks after surgery. Between test sessions, patients were randomly assigned to a course of either closed or open kinetic chain resistance exercises (3 sessions per week for 4 weeks). Gait analysis consisted of bilateral calculations of knee joint angle, moment, and power during level walking, stair ascent, and stair descent. An analysis of variance on the effects of training group and test session indicated that the only variable to be significantly affected by the type of exercise program was the amount of knee flexion at the beginning of step-up (P < 0.05). All other measures of knee angle, moment, and power (16 total variables) showed no significant difference between the exercise groups. All variables measured on the injured side showed significant improvement from test 1 to test 2 (P < 0.05), but the injured leg remained functionally deficient when compared with the uninjured leg. These data suggest that there are no clinically significant differences in the functional improvement resulting from the choice of open or closed kinetic chain exercises in the early period after this surgery.     

Bracing versus nonbracing in rehabilitation after anterior cruciate ligament reconstruction: a randomized prospective study with 2-year follow-up

This study prospectively randomized 62 patients to rehabilitation programs either with or without postoperative brace for 6 weeks following bone-tendon-bone anterior cruciate ligament reconstruction. The nonbraced group had a smaller knee circumference 2 weeks after surgery. At 6-month follow-up the nonbraced group had a better Tegner score. At 2 years there was no difference between the groups. There was one partial rupture of the graft in the nonbraced group after a new trauma 1 year after surgery. There were no differences between the groups in either subjective or objective knee stability at 2 or 6 weeks or at follow-up 3, 6, and 24 months after surgery. This study found no benefit of using a postoperative knee brace on patients' knee function at any stage up to 24 months after surgery. Furthermore, the braced group was not more stable than the nonbraced group, indicating that the brace does not contribute to a more stable knee during rehabilitation or 2-year follow-up.     

Functional bracing after anterior cruciate ligament reconstruction: a prospective, randomized, multicenter study

BACKGROUND: Bracing after anterior cruciate ligament reconstruction is expensive and is not proven to prevent injuries or influence outcomes. PURPOSE: To determine whether postoperative functional knee bracing influences outcomes. STUDY DESIGN: Prospective, randomized, multicenter clinical trial. METHODS: One hundred volunteers from the 3 US service academies with acute anterior cruciate ligament tears were randomized into braced or nonbraced groups. Only those subjects with anterior cruciate ligament tears treated surgically within the first 8 weeks of injury were included. Patients with chondral injuries, significant meniscal tears, or multiple knee ligament injuries were excluded. Surgical procedures and the postoperative physical therapy protocols were identical for both groups. The braced group was instructed to wear an off-the-shelf functional knee brace for all cutting, pivoting, or jumping activities for the first year after surgery. RESULTS: Ninety-five subjects were available with a minimum 2-year follow-up. There were no statistically significant differences between groups in knee stability, functional testing with the single-legged hop test, International Knee Documentation Committee scores, Lysholm scores, knee range of motion, or isokinetic strength testing. Two braced subjects had reinjuries, and 3 nonbraced subjects had reinjuries. CONCLUSIONS: In this young, active population, postoperative bracing does not appear to change the clinical outcomes after anterior cruciate ligament reconstruction.     

Fear of re-injury: a hindrance for returning to sports after anterior cruciate ligament reconstruction

Unrestricted participation in sports activities and return to the pre-injury level is often reported as an indicator of the success of ACL reconstruction. The athletes choice not to return to their pre-injury level may depend on the knee function, but some times, social reasons or psychological hindrances such as fear of re-injury may influence their return to sports. The aim of this study was to investigate whether fear of re-injury due to movement is of significance for returning to previous level of activity in patients who have undergone anterior cruciate ligament reconstruction. The Tampa Scale of Kinesiophobia (TSK), the Knee Injury and Osteoarthritis Outcome Score (KOOS) and some general questions were mailed to 87 patients who underwent ACL reconstruction 3–4 years before the study was conducted. Sixty-two patients (74%) answered the questionnaires (34 men and 28 women). Fifty-three percent of the patients returned to their pre-injury activity level. The patients who did not return to their pre-injury activity level had more fear of re-injury, which was reflected in the TSK. In addition, high fear of re-injury was correlated with low knee-related quality of life. Fear of re-injury must be considered in the rehabilitation and evaluation of the effects of an ACL reconstruction.