Hamstring muscles play a major role in knee-joint stabilization after anterior cruciate ligament (ACL) injury. Weakness of the knee extensors after ACL reconstruction with patellar tendon (PT) graft, and in the knee flexors after reconstruction with hamstring tendons (HT) graft has been observed up to 2 years post surgery, but not later. In these studies, isokinetic muscle torque was used. However, muscle power has been suggested to be a more sensitive and sport-specific measures of strength. The aim was to study quadriceps and hamstring muscle power in patients with ACL injury treated with surgical reconstruction with PT or HT grafts at a mean of 3 years after surgery. Twenty subjects with PT and 16 subjects with HT grafts (mean age at follow up 30 years, range 20-39, 25% women), who were all included in a prospective study and followed the same goal-based rehabilitation protocol for at least 4 months, were assessed with reliable, valid, and responsive tests of quadriceps and hamstring muscle power at 3 years (SD 0.9, range 2-5) after surgery. The mean difference between legs (injured minus uninjured), the hamstring to quadriceps (H:Q, hamstring divided by quadriceps) ratio, and the limb symmetry index (LSI, injured leg divided by uninjured and multiplied by 100) value, were used for comparisons between the groups (analysis of variance). The mean difference between the injured and uninjured legs was greater in the HT than in the PT group for knee flexion power (-21.3 vs. 7.7 W, p = 0.001). Patients with HT graft had lower H:Q ratio in the injured leg than the patients with PT graft (0.63 vs. 0.77, p = 0.012). They also had lower LSI for knee flexion power than those in the PT group (88 vs. 106%, p < 0.001). No differences were found between the groups for knee extension power. The lower hamstring muscle power, and the lower hamstring to quadriceps ratio in the HT graft group than in the PT graft group 3 years (range 2-5) after ACL reconstruction, reflect imbalance of knee muscles after reconstruction with HT graft that may have a negative effect on dynamic knee-joint stabilization.
"The KOOS survey has been validated  and contains five separate subscales; (i) Pain, (ii) Other Symptoms, (iii) Function in daily living (ADL), (iv) Function in Sport and Recreation (Sport/Rec), and (v) joint related Quality of Life (QOL)  . Sport/Rec and QOL were the only KOOS subscales that were analyzed in the present study, since these two subscales are most dominantly affected by ACL-injury   and also are the subscales most frequently studied in the research setting  . Prior to testing patients performed a standardized warm-up program consisting of two repetitions of 10 toe rises, 10 bilateral squats, 10 unilateral squats (for each leg) and two to three submaximal vertical jumps (Countermovement jumps: CMJ). "
[Show abstract][Hide abstract] ABSTRACT: Background: Associations between objective and subjective measures of knee function may facilitate rehabilitation in ACL-patients. Aim: The aim of this study is to investigate if a test-battery of functional and/or muscle outcomes are associated with Knee osteoarthritis outcome score (KOOS) subscales (Sport/Rec and QOL) in ACL-reconstructed patients. Methods: 23 hamstring auto-graft ACL-reconstructed men (mean age: 27.2 standard deviation 7.5 years, BMI: 25.4 standard deviation 3.2 time since surgery: 27 standard deviation 7 months) completed KOOS-questionnaire and an objective test-battery: (i) one-leg maximal jump for distance (OLJD), isometric maximal voluntary contraction (MVC) for (ii) knee extensors and (iii) flexors, and (iv) maximal counter movement jump (CMJ). Sagittal kinematic data were recorded during CMJ using a 6-camera Vicon MX system. Multilevel linear regression analysis was used to determine the strength of associations between KOOS parameters (Sport/Rec and QOL) that a priori were defined as dependent variables and 4 models of independent outcomes from the test-battery. Results: Moderate associations between OLJD and Sport/Rec (r(2) = 0.26, p < 0.01) and QOL (r(2) = 0.26, p < 0.01) were observed (Model 1). Adding knee extensor or flexor MVC to the analysis (Model 2) increased the strength of the associations (up to r(2) = 0.53, p < 0.01, and r(2) = 0.31, p = 0.02 for Sport/Rec and QOL, respectively). Adding both knee extensor and knee flexor MVC to the analysis (Model 3) did not improve the regression model and only minor increases were observed when including kinematic data of CMJ (Model 4). Conclusion: Moderate-to-large proportion (31-53%) of the variation in KOOS was explained by OLJD and MVC which may add to design effective future rehabilitation interventions for ACL-patients.
The Knee 10/2014; 21(6). DOI:10.1016/j.knee.2014.09.004 · 1.94 Impact Factor
"Also, the achieved improvements are evident in measures of motor function (muscle strength, functional performance), but the possible influence of training on sensory function (proprioceptive acuity) remains uncertain [3,4,6]. The importance of sensorimotor function is reflected by its association with the patient’s perceived knee-related function and quality of life [7-9], and its potential protective role for detrimental long-term consequences, such as osteoarthritis (OA) [10-12]. From this perspective, treatment resulting in improved sensorimotor function would be of value for patients with knee injury and OA in the short and long term. "
[Show abstract][Hide abstract] ABSTRACT: Severe traumatic knee injury, including injury to the anterior cruciate ligament (ACL), leads to impaired sensorimotor function. Although improvements are achieved by training, impairment often persists. Because good sensorimotor function is associated with better patient-reported function and a potential lower risk of future joint problems, more effective treatment is warranted. Temporary cutaneous anesthesia of adjacent body parts was successfully used on the hand and foot to improve sensorimotor function. The aim of this study was to test whether this principle of brain plasticity could be used on the knee. The hypothesis was that temporary anesthesia of the skin area above and below the knee would improve sensorimotor function of the ipsilateral knee and leg in subjects with ACL injury.
In this double-blind exploratory study, 39 subjects with ACL injury (mean age 24 years, SD 5.2, 49% women, mean 52 weeks after injury or reconstruction) and self-reported functional limitations and lack of trust in the knee were randomized to temporary local cutaneous application of anesthetic (EMLA®) (n = 20) or placebo cream (n = 19). Fifty grams of EMLA®, or placebo, was applied on the leg 10 cm above and 10 cm below the center of patella, leaving the area around the knee without cream. Measures of sensory function (perception of touch, vibration sense, knee kinesthesia) and motor function (knee muscle strength, hop test) were assessed before and after 90 minutes of treatment with EMLA® or placebo. The paired t-test was used for comparisons within groups and analysis of variance between groups, except for ordinal data where the Wilcoxon signed rank test, or Mann-Whitney test, was used. The number of subjects needed was determined by an a priori sample size calculation.
No statistically significant or clinically relevant differences were seen over time (before vs. after) in the measures of sensory or motor functions in the EMLA® group or in the placebo group. There were no differences between the groups due to treatment effect (EMLA® vs. placebo).
Temporary cutaneous anesthesia of adjacent body parts had no effect in improving sensorimotor function of the knee and leg in subjects with severe traumatic knee ligament injury.
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