Principles for aggressive rehabilitation after reconstruction of the anterior cruciate ligament

In vivo tibiofemoral kinematics during 4 functional tasks of increasing demand using biplane fluoroscopy

BACKGROUND

The anterior cruciate ligament (ACL) has been well defined as the main passive restraint to anterior tibial translation (ATT) in the knee and plays an important role in rotational stability. However, it is unknown how closely the ACL and other passive and active structures of the knee constrain translations and rotations across a set of functional activities of increasing demand on the quadriceps.

HYPOTHESIS

Anterior tibial translation and internal rotation of the tibia relative to the femur would increase as the demand on the quadriceps increased.

STUDY DESIGN

Controlled laboratory study.

METHODS

The in vivo 3-dimensional knee kinematics of 10 adult female patients (height, 167.8 ± 7.1 cm; body mass, 57 ± 4 kg; body mass index [BMI], 24.8 ± 1.7 kg/m(2); age, 29.7 ± 7.9 years) was measured using biplane fluoroscopy while patients completed 4 functional tasks. The tasks included an unloaded knee extension in which the patient slowly extended the knee from 90° to 0° of flexion in 2 seconds; walking at a constant pace of 90 steps per minute; a maximum effort isometric knee extension with the knee at 70° of flexion; and landing from a height of 40 cm in which the patient stepped off a box, landed, and immediately performed a maximum effort vertical jump.

RESULTS

Landing (5.6 ± 1.9 mm) produced significantly greater peak ATT than walking (3.1 ± 2.2 mm) and unweighted full extension (2.6 ± 2.1 mm) (P < .01), but there was no difference between landing and a maximum isometric contraction (5.0 ± 1.9 mm). While there was no significant difference in peak internal rotation between landing (19.4° ± 5.7°), maximum isometric contraction (15.9° ± 6.7°), and unweighted full knee extension (14.5° ± 7.7°), each produced significantly greater internal rotation than walking (3.9° ± 4.2°) (P < .001). Knee extension torque significantly increased for each task (P < .01): unweighted knee extension (4.7 ± 1.2 N·m), walking (36.5 ± 7.9 N·m), maximum isometric knee extension (105.1 ± 8.2 N·m), and landing (140.2 ± 26.2 N·m).

CONCLUSION

Anterior tibial translations significantly increased as demand on the quadriceps and external loading increased. Internal rotation was not significantly different between landing, isometric contraction, and unweighted knee extension. Additionally, ATT and internal rotation from each motion were within the normal range, and no excessive amounts of translation or rotation were observed.

CLINICAL RELEVANCE

This study demonstrated that while ATT will increase as demand on the quadriceps and external loading increases, the knee is able to effectively constrain ATT and internal rotation. This suggests that the healthy knee has a safe envelope of function that is tightly controlled even though task demand is elevated.

Medium term follow up of endoscopically assisted BPTB ACL reconstruction using a two-incision technique--return to sporting activity

We report our findings of a prospective outcome study of a series of 50 patients with chronic ACL injury undergoing arthroscopically assisted bone-patellar-tendon-bone ACL reconstruction. Patients underwent reconstruction if they had instability precluding participation in sport at the desired level and were reviewed at a mean of 62 months. Clinical examination was carried out pre and post operatively. Assessment was augmented by KT 1000 measurement, Tegner activity score and Lysholm score. Surgery was considered a failure if the Pivot Shift test was 2+(jerk) or symptoms of instability persisted. By these criteria 48 patients were successfully treated. Our results show a good medium term outcome for this reconstructive method. We had a 94% return to sporting activity but at a lower than expected activity level. Clinical examination showed an improvement and we recorded excellent or good results on Lysholm score in all these patients.

Rehabilitation after hamstring anterior cruciate ligament reconstruction

A prospective comparative study was conducted involving 62 patients to determine the effects and limits of accelerated rehabilitation on clinical outcome. The study focused on whether aggressive rehabilitation after anterior cruciate ligament reconstruction with the doubled semitendinosus and gracilis tendon autograft results in stretching the graft. Thirty patients had postoperative rehabilitation according to the current conservative protocol, and 32 patients had rehabilitation using an accelerated regime. Each patient was evaluated subjectively and objectively 36 months or more after surgery. Concerning the side-to-side difference in the anterior laxity, 87% of the patients in the conservative rehabilitation group had 3 mm or less and 80% of the patients in the accelerated rehabilitation group had the same acceptable laxity. There was no significant difference between the two groups. Muscle torque was restored significantly earlier in the patients in the accelerated rehabilitation group than in the patients in the conservative rehabilitation group. Nine months after surgery, however, there were no significant differences in the torque between the two groups. Accelerated rehabilitation significantly increased the incidence of knee effusion during rehabilitation. This study showed that acceleration of postoperative rehabilitation could rapidly restore muscle strength without significantly compromising graft stability in anterior cruciate ligament reconstruction with the doubled hamstring tendon autograft. However, this study also showed that acceleration significantly increases the incidence of synovitis. Acceleration of postoperative rehabilitation has advantages and disadvantages for clinical outcome after anterior cruciate ligament reconstruction.

Efficacy of stairclimber versus cycle ergometry in postoperative anterior cruciate ligament rehabilitation

OBJECTIVE

To examine the effective use of stair climbing as an alternative to cycling for knee rehabilitation in an actual injured sport population.

DESIGN

Repeated-measures multivariate analyses with data collected during anterior cruciate ligament (ACL) rehabilitation.

SETTING

Clinical rehabilitation setting following ACL reconstruction.

PARTICIPANTS

46 athletes with ACL reconstruction (32 males, 14 females; age 25.5 +/- 8.9 yrs) were randomly assigned to either cycle or stairclimber programs previously matched by metabolic equivalents (METs) and heart rate.

MAIN OUTCOME MEASURES

Isokinetic testing was performed at 4 and 12 weeks postoperatively on the uninjured knee to safely determine mean and peak concentric quadriceps, eccentric quadriceps, concentric hamstring, and eccentric hamstring peak torques. Pre/post leg girths were also measured bilaterally (+7.6, +15.2, +22.9, -7.6, -15.2, -22.9 cm) proximal/distal to the patella.

RESULTS

Multivariate analysis of variance indicated no differences (Wilks' Lambda F(8,37) = 1.461; p = 0.21; eta(2) = 0.240; Power = 0.556) in strength gains (NM) between cycle and stair climbing groups, respectively, in mean concentric quadriceps (58.4 +/- 12.0 vs. 37.1 +/- 13.2), peak concentric quadriceps (77.0 +/- 14.7 vs. 36.8 +/- 16.2), mean eccentric quadriceps (57.2 +/- 12.7 vs. 79.2 +/- 14.0), peak eccentric quadriceps (78.6 +/- 19.3 vs. 105.5 +/- 21.3), mean concentric hamstring (14.3 +/- 3.9 vs. 6.5 +/- 4.3), peak concentric hamstring (24.0 +/- 6.7 vs. 22.2 +/- 7.4), mean eccentric hamstring (22.6 +/- 8.6 vs. 23.8 +/- 9.5), or peak eccentric hamstring (23.5 +/- 11.2 vs. 36.7 +/- 12.3) response. A significant stair climbing effect (Wilks' Lambda F(6,37) = 2.95; p = 0.02; eta(2) = 0.324; Power = 0.843) was observed in gastrocnemius girth (-15.2 cm) in both injured (0.5 +/- 0.1 cm vs. 0.3 +/- 0.1 cm, p < 0.04) and non-injured (0.3 +/- 0.1 cm vs. 0.0 +/- 0.1 cm, p < 0.008) legs.

CONCLUSIONS

In conclusion, the results of the data suggest no deleterious effect of stair climbing on knee isokinetic performance or limb girth measurements, and confirms the use of stair climbing as a viable adjunct/alternative to cycle ergometry in ACL-injured athletes.

The influence of functional knee bracing on the anterior cruciate ligament strain biomechanics in weightbearing and nonweightbearing knees

Functional knee braces are commonly prescribed after anterior cruciate ligament injury or reconstruction; however, their ability to protect the ligament, or graft, remains unclear. Our objective was to evaluate the anterior cruciate ligament strain response in braced and unbraced knees during weightbearing and nonweightbearing in combination with three externally applied loads: 1) anterior-posterior shear forces, 2) internal-external torques, and 3) varus-valgus moments. The Legend brace was tested. All external loads were applied to the tibia with the knee flexed to 20 degrees. Reproducible data were obtained from 11 subjects. For anterior shear loads up to 130 N, the brace significantly reduced strain values compared with the unbraced knee during nonweightbearing and weightbearing conditions. For internal torques of the tibia (up to 9 N x m), strain in the braced knee was significantly less than in the unbraced knee when the knee was nonweightbearing only. The brace did not reduce strain values when the knee was subjected to external torques (9 N x m) or varus-valgus moments (10 N x m) in weightbearing and nonweightbearing knees. These data indicate that a functional knee brace can protect the anterior cruciate ligament during anterior-posterior shear loading in the nonweightbearing and weightbearing knee and during internal torques in the nonweightbearing knee.

The effect of exercise and rehabilitation on anterior-posterior knee displacements after anterior cruciate ligament autograft reconstruction

We studied the effect of rehabilitation strength training and return to activities on anterior-posterior knee displacements after patellar tendon autogenous anterior cruciate ligament reconstruction. A total of 938 measurements were sequentially collected for 142 patients with the KT-2000 arthrometer. Rehabilitation included immediate knee motion and early weightbearing, light sports at 6 months, and competitive sports at 8 months or later. At a minimum of 2 years after surgery, 121 patients (85%) had normal displacements (less than 3 mm of increase at 134 N), 14 (10%) had 3 to 5.5 mm of increase (partial function), and 7 (5%) had more than 5.5 mm of increase (failed). There was no association found between the initial onset of the abnormal displacements in the 21 knees and either the amount of time after surgery or the rehabilitation program. Six of the seven grafts that failed did so in the 1st postoperative year. Serial displacement measurements allow early detection of graft stretching and subsequent modification of rehabilitation or delay in return to strenuous activities. These measurements showed that the rehabilitation program used in this study was not itself injurious and resulted in an acceptable failure rate of 5%.

Hamstring Muscle Strength Prior to and Following ACL Reconstruction Surgery Using a Patellar Tendon Autograft

Due to the likelihood of hamstring dysfunction associated with anterior cruciate ligament (ACL) injury, it is clinically significant to determine if a hamstring weakness exists preoperatively. The purpose of this study was to determine if a hamstring muscle deficit existed at the time of surgery and to determine the time necessary to achieve hamstring strength equal to preoperative measures of the uninvolved extremity during postoperative rehabilitation. Twelve patients who underwent ACL reconstruction using a patellar tendon autograft participated. Each subject underwent a preoperative isometric knee strength evaluation at 60° of knee flexion. Each subject underwent postoperative rehabilitation including hamstring muscle strengthening. Repeat isometric testing was performed on each subject at 21 and 42 days postoperative. There was no statistical difference in hamstring muscle strength, as measured by isometric peak torque, either preoperatively or postoperatively. Therefore, maintaining rather than increasing hamstring strength postoperatively should be emphasized as an integral part of rehabilitation.

Arthroscopic repair of meniscal tears that extend into the avascular zone. A review of 198 single and complex tears

We assessed the results of 198 meniscal tears that had a major segment in the central avascular region repaired with an arthroscopically assisted inside-out technique. There were 177 patients whose mean age was 28 years. Eighty-two percent were injured during sports, and 71% also required anterior cruciate ligament reconstruction. The menisci were evaluated by clinical examination (180 repairs) a mean of 42 months postoperatively, by follow-up arthroscopic evaluation (91 repairs) a mean of 18 months postoperatively, or both. At followup, 159 (80%) of the 198 tears were asymptomatic for tibiofemoral joint symptoms, and 39 (20%) required repeat arthroscopic surgery for these symptoms. Of the 91 repairs evaluated arthroscopically, 23 (25%) were classified as healed, 35 (38%) as partially healed, and 33 (36%) as failed. We recommend repair of meniscal tears that extend into the avascular region for select patients, including those in their 20s and 30s and highly competitive athletes. This study's reoperation rate of 20% should not be interpreted as the rate of meniscal healing, but as the incidence of tibiofemoral joint symptoms. Even though this is a higher rate than that reported for the repair of peripheral meniscal tears, we believe the benefits of a potentially functional meniscus outweigh the risks of reoperation.

A comparison of results of arthroscopic-assisted anterior cruciate ligament reconstruction between workers' compensation and noncompensation patients

This investigation compared the results of arthroscopic-assisted anterior cruciate ligament patellar tendon autogenous reconstruction in patients who received Workers' Compensation (WC) benefits with results of similar surgery in patients who did not receive such benefits, to determine if differences existed based on this variable alone. Thirty-eight patients (19 WC benefits, 19 NoWC) were matched for age, injury chronicity, number of prior operations, and months of follow-up. All had the same operation and rehabilitation. A significant difference was found between the groups in the mean number of days of lost employment preoperatively (WC, 122 days; NoWC, 3 days) and postoperatively (WC, 222 days; NoWC, 37 days). At follow-up (mean, 27 months), 17 patients in group WC had returned to work (6 with symptoms) and 2 were disabled. All patients in group NoWC had returned to work, 2 with symptoms. There was no significant difference between the groups for anterior-posterior displacements, functional limitations with daily or sports activities, patient perception of the knee condition, the overall rating score, or complications. The number of mean days of lost employment in group WC could not be accounted for from factors that normally effect anterior cruciate ligament reconstruction results. We hypothesize that other factors such as wage systems that support WC injuries long-term, inability of employers to modify job requirements, inability of employees to receive job retraining, or lack of proper immediate diagnosis and treatment of the injury, may have lead to the large number of lost working days in group WC.

Arthroscopic anterior cruciate ligament reconstruction

Significant advances in arthroscopic techniques have led to wide-spread performance of arthroscopically assisted ACL reconstruction. Properly performed reconstruction has proved to be successful clinically. The surgeon who undertakes ACL reconstruction must be familiar with techniques for both autograft hamstring augmentation and bone-patellar tendon-bone ACL reconstruction for the ACL-deficient knee. The arthroscopic techniques discussed in this article will allow successful treatment of most acute and chronic ACL injuries. Arthroscopic ACL reconstruction is a highly demanding procedure, with the possible risk of significant knee disability if the ACL graft is placed improperly. Proper patient selection, surgical technique, and postoperative rehabilitation remain the foundations for successful ACL reconstruction.

Anterior tibial translation during progressive loading of the ACL-deficient knee during weight-bearing and nonweight-bearing isometric exercise

Many protocols for rehabilitating the knee following anterior cruciate ligament (ACL) injury or repair call for the use of both weight-bearing and nonweight-bearing exercises. However, not much is known about the strain these exercises place on the passive restraining mechanisms. The purpose of this study was to examine the effect of progressive loading of the knee extensors on anterior tibial translation during weight-bearing and nonweight-bearing isometric exercise. Fourteen subjects diagnosed as ACL-deficient via arthroscopic surgery participated in the study. An arthrometer was used to measure anterior tibial translation during weight-bearing and nonweight-bearing exercises with the knee in 20 degrees of flexion and with a quadriceps load equivalent to 25, 50, 75, and 100% of body weight. Hamstring muscle activations during all testing were monitored to eliminate the possibility of substantial cocontractions. During the weight-bearing exercise, anterior tibial translation was found to be significantly less than that measured during the Lachman's evaluation and the 50, 75, and 100% nonweight-bearing exercises. For the nonweight-bearing exercises, anterior tibial translation was either equivalent to or greater than the Lachman's evaluation. During the weight-bearing exercises, anterior tibial translation was not different under the different loading conditions. During the nonweight-bearing exercises, anterior tibial translation progressively increased with increased loading. The results from this study imply that weight-bearing exercises minimize strain to the passive restraining structures whereas nonweight-bearing exercises will strain these structures, and the magnitude of this strain appears to be proportional to the knee extensor moment.