Uninjured Knee Research Articles

The Severity and Prediction of Anterior Knee Pain Post Tibial Nail Insertion

To compare the prevalence of anterior knee pain and functional impairment post-tibial nailing to the contralateral knee and a background population. Patients were assessed by postal questionnaire, case note, and radiographic review. An age demographically matched control group answered the same questions. The Orthopaedic Department at our institution. Patients who had a tibial nail inserted between September 1999 and November 2004 in our hospital (85 patients). Twelve were excluded, and 52 replies from 73 cases (71%) were received. The mean age was 39.4 years (range 22-69), and 38 of the patients were men. Patients treated with AO tibial nail. Both knees were assessed using an analogue pain score (0-10) and a functional anterior knee pain score (0-50). Of the patients, 83% had anterior knee pain following tibial nailing. The mean analogue pain score was 4.3, and the functional score was 33.3. The prevalence of anterior knee pain in the uninjured knee was 40%; in the control group it was 42%. Mean visual analogue scores were 1.3 and 1.2, respectively (both P<0.001 compared to the nailed side). Functional knee pain scores were 43.3 and 46.8 (both P<0.001 compared to the nailed side). Pain scores between both the knee on the injured and the contralateral sides correlated significantly (P<0.01). Last, the pain scores of the patients' knees of the uninjured side in the operative group and the scores from the control group appeared similar but not with statistical significance (P<0.57 analogue pain score and P<0.77 functional knee pain score). There is a significant preinjury prevalence of anterior knee pain. Postnailing knee pain severity correlates with that in the uninjured limb. Relative risk of anterior knee pain postnailing is twice that of a comparative population.

Contralateral limb strength deficits after anterior cruciate ligament reconstruction using a hamstring tendon graft

The purpose of this study was to determine whether current post-operative rehabilitation protocols return the strength of the contralateral uninjured limb knee flexors and extensors after an anterior cruciate ligament (ACL) reconstruction to those of an uninjured control group. Subjects with a hamstring tendon ACL reconstruction (n=12) were compared to an active control group (n=30). Comprehensive bilateral knee flexor and extensor isovelocity strength testing was performed (five speeds, 5-95 degrees , concentric and eccentric contractions). After hamstring tendon ACL reconstruction and rehabilitation, bilateral strength normalization (within 10% of the contralateral limb) is achieved by the knee extensors but not the knee flexors. When compared to the uninjured control group, large and statistically significant strength deficits were demonstrated in the knee extensors and knee flexors of both the anterior cruciate ligament reconstructed (extensors 24.8%; flexors 26.8%) and the contralateral uninjured (extensors 21%; flexors 13.5%) limbs. These findings suggest that improvement can be made in knee flexor rehabilitation after ACL reconstruction and limit the validity of the use of a contralateral leg as a rehabilitation endpoint or as a control in the ACL reconstructed population.

The Effect of Tibial Rotation on the Presence of Instability in the Anterior Cruciate Ligament Deficient Knee

The effects of tibial rotation after ACL injury have not yet been well determined. To show whether clinical outcomes such as the amount of tibial rotation can affect functional outcomes in normal and ACL deficient knees. Case control study. Research laboratory. Twenty normal subjects (Control) and 20 subjects with ACL deficient knees (ACL). Tibial rotation at 30 and 90 degrees of knee flexion was measured using an inclinometer. One-legged hop, crossover hop, figure-of-eight running and 10-m running tests were used and determined the effect(s) of tibial rotation on the outcome of the functional tests. There were significant between-group differences in internal and external rotation. The relationship between external tibial rotation and the figure-of-eight index was significantly negatively correlated. The amount of tibial rotation is greater in ACL ruptured knees than in uninjured knees, and these greater amounts of tibial rotation affected the figure-of-eight running index.

Dynamic Function of the ACL-reconstructed Knee during Running

Little is known about the three-dimensional behavior of the anterior cruciate ligament (ACL) reconstructed knee during dynamic, functional loading, or how dynamic knee function changes over time in the reconstructed knee. We hypothesized dynamic, in vivo function of the ACL-reconstructed knee is different from the contralateral, uninjured knee and changes over time. We measured knee kinematics for 16 subjects during downhill running 5 and 12 months after ACL reconstruction (bone-patellar tendon-bone or quadrupled hamstring tendon with interference screw fixation) using a 250 frame per second stereoradiographic system. We used repeated-measures ANOVA to ascertain whether there were differences between the uninjured and reconstructed limbs and over time. We found no differences in anterior tibial translation between limbs, but reconstructed knees were more externally rotated and in more adduction (varus) during the stance phase of running. Anterior tibial translation increased from 5 to 12 months after surgery in the reconstructed knees. Anterior cruciate ligament reconstruction failed to restore normal rotational knee kinematics during dynamic, functional loading and some degradation of graft function occurred over time. These abnormal motions may contribute to long-term joint degeneration associated with ACL injury and reconstruction.

Correlates of Knee Extensor Training Load Used in Rehabilitation After Knee Surgery

Resistance training is one of the major components of rehabilitation after musculoskeletal injury and surgery. Despite the importance of resistance training and the frequency of its use in rehabilitation, little is known about factors that are related to training load that might be useful in devising and monitoring training in a patient and comparing training intensities between individuals and groups. We hypothesized that the following would show a statistically significant relationship to training load: injury chronicity, self-assessed knee function (Hughston Clinic questionnaire), knee swelling (injured-uninjured midpatellar knee girth), uninjured knee girth, and body mass. The purpose of this study was to evaluate whether factors such as body mass are related to the load used in training the knee extensors in rehabilitation after knee surgery. Thirty-six individuals undergoing early-phase rehabilitation after knee arthroscopic meniscectomy surgery participated in this study. Subjects were tested 5 days after surgery, just prior to commencing a 6-week outpatient rehabilitation program, and again soon after the end of this rehabilitation program. The independent variables evaluated were age, gender, body mass, meniscus injured, injury chronicity, knee function self-assessment, knee swelling (injured-uninjured midpatellar girth), uninjured knee girth, and knee flexion and extension passive range of motion (difference between injured and uninjured side). The dependent variable was the load used for training the knee extensors on the knee extension machine in the final training session prior to the posttest. The only variable exhibiting a statistically significant (p = 0.001) relationship to knee extensor final training was age (r = -0.529). This finding, that age was the only variable to have a significant relationship with training load, suggests that clinicians' expectation of training intensity should decrease with an increase in the patient's age in the range studied (20-58 years) for patients recovering from knee arthroscopic meniscectomy.

Kinematic study following double-bundle, anterior cruciate ligament reconstruction

The purpose of this study was to evaluate tibiofemoral kinematics after double-bundle anterior cruciate ligament (ACL) reconstructions and compare them with those of successful single-bundle reconstructions and contralateral normal knees using open MR images. We obtained MR images based on the flexion angle without weight-bearing, from 20 patients with successful unilateral single-bundle (10 patients) and double-bundle (10 patients) ACL reconstructions with tibialis anterior allografts and a minimum 1-year follow-up. The MR images of the contralateral uninjured knees were used as normal controls. Sagittal images of the mid-medial and mid-lateral sections of the tibiofemoral compartments were used to measure the translation of the femoral condyles relative to the tibia. The mean translations of the medial femoral condyles on the tibial plateaus during knee joint motion showed no significant differences among normal, single-bundle, and double-bundle ACL reconstructed knees (all p>0.05). The mean translations of the lateral femoral condyles showed a significant difference between normal and single-bundle reconstructed knees, or between single-bundle and double-bundle reconstructed knees (p<0.05). However, there was no significant difference between normal and double-bundle reconstructed knees (p=0.220). These findings suggest that double-bundle ACL reconstruction restores normal kinematic tibiofemoral motion better than single-bundle reconstruction.

Midterm and Long-term Results after Arthroscopic Suture Repair of Isolated, Longitudinal, Vertical Meniscal Tears in Stable Knees

Background The long-term outcome of meniscal suture repair has not been firmly established. Purpose To compare the midterm and long-term functional and radiographic outcome of meniscal suture repairs with the natural history of the uninjured knees of each of a cohort of patients. Study Design Cohort study; Level of evidence, 3. Methods Eighty-eight patients with an isolated, longitudinal, vertical tear of one of the menisci within a stable knee were arthroscopically treated with a meniscal suture repair. No patient had a previous surgery, and no additional chondral lesion was present. The opposite knee of each patient was uninjured. Both knees of each patient were examined clinically and radiographically in a retrospective follow-up 5 to 17 years (mean, 10 years) after meniscal repair. Results Three patients with postoperative complications and 21 patients whose menisci had to be removed because of rerupture were excluded from further evaluation for purposes of this study. The remaining 64 patients reached a mean Tegner activity level of 6 points (range, 3-10 points) and achieved a mean Lysholm score of 94 points (range, 26-100 points). Osteoarthritis was found in 46 of the injured knees, compared with 27 of the uninjured knees (P = .004). However, 42 of the patients had no difference in the grade of osteoarthritis between the injured knee and the uninjured knee, 19 had a difference of 1 grade, 2 had a difference of 2 grades, and 1 had a difference of 3 grades. Conclusion Arthroscopic meniscal repair for isolated longitudinal meniscal injuries in stable knees yields favorable functional results, but its effects on the risk of secondary osteoarthritis are not clear.

MRI analysis of in vivo meniscal and tibiofemoral kinematics in ACL‐deficient and normal knees

The objectives of this study were to analyze simultaneously meniscal and tibiofemoral kinematics in healthy volunteers and anterior cruciate ligament (ACL)-deficient patients under axial load-bearing conditions using magnetic resonance imaging (MRI). Ten healthy volunteers and eight ACL-deficient patients were examined with a high-field, closed MRI system. For each group, both knees were imaged at full extension and partial flexion ( approximately 45 degrees ) with a 125N compressive load applied to the foot. Anteroposterior and medial/lateral femoral and meniscal translations were analyzed following three-dimensional, landmark-matching registration. Interobserver and intraobserver reproducibilities were less than 0.8 mm for femoral translation for image processing and data analysis. The position of the femur relative to the tibia in the ACL-deficient knee was 2.6 mm posterior to that of the contralateral, normal knee at extension. During flexion from 0 degrees to 45 degrees , the femur in ACL-deficient knees translated 4.3 mm anteriorly, whereas no significant translation occurred in uninjured knees. The contact area centroid on the tibia in ACL-deficient knees at extension was posterior to that of uninjured knees. Consequently, significantly less posterior translation of the contact centroid occurred in the medial tibial condyle in ACL-deficient knees during flexion. Meniscal translation, however, was nearly the same in both groups. Axial load-bearing MRI is a noninvasive and reproducible method for evaluating tibiofemoral and meniscal kinematics. The results demonstrated that ACL deficiency led to significant changes in bone kinematics, but negligible changes in the movement of the menisci. These results help explain the increased risk of meniscal tears and osteoarthritis in chronic ACL deficient knees.

Morphometric side-to-side differences in human cruciate ligament insertions

Graft placement in cruciate ligament reconstruction is known to significantly influence postoperative knee stability and range of motion. Improvement of bone tunnel positioning has been advocated by computer-assisted surgical procedures that require reliable input and reference data. This study validates the hypothesis that morphometric reference data can be obtained from the uninjured controlateral knee for accurate bone tunnel and graft positioning. Thirty pairs of human cadaver knees were dissected and the femoral and tibial footprints of the anterior and posterior cruciate ligaments (PCL) were radiopaquely marked. Radiographs were taken of the corresponding left- and right-sided femora and tibiae, and digitally processed. Controlateral specimens were mirrored and overlapped precisely, the areas and intersections of ligament insertion were digitally determined. There were no significant differences in the total area of cruciate ligament insertion between left and right knee specimens or between female and male specimens. Intersection areas (IAs) in femoral and tibial anterior cruciate ligament (ACL) insertions averaged 31.3 and 33.4% of the total insertion area, respectively. The center of gravity for the femoral and tibial ACL footprint differed by 4.7 and 4.5 mm between left and right knees, respectively. IAs in femoral and tibial PCL insertions averaged 46.1 and 61.3% of the total insertion area, respectively. The center of gravity for the femoral and tibial PCL footprint differed by 4.5 and 2.4 mm between left and right knees, respectively. Our study does not support the concept of obtaining morphologic reference data from the uninjured controlateral knee for individual bone tunnel placement.

Beobachtungen an gesunden und VKB-insuffizienten Kniegelenken nach Belastungs-MRT

The Lachman test is the most reliable clinical test for diagnosing rupture of the anterior cruciate ligament (ACL). Previous X-ray studies have presented a "radiologic Lachman test". Recently anterior tibial translation was demonstrated using open access MRI. Two methods were developed to transfer a similar technique to a more widely available closed MRI. Using closed MRI we investigated 22 knees in 21 patients with pure rupture of the ACL. Anteriorly and posteriorly directed shear forces were applied to the tibiofemoral joint at 20 degrees flexion either by positioning a 9-kg load on the distal femur (method 1) or performing a semi-manual Lachman test with a custom-made orthosis (method 2). Both methods produced relative anterior tibial translation in both compartments of the normal and ACL-deficient knee which could be measured on sagittal images. They were greater laterally than medially and in injured than in uninjured knees. However, instability of the medial compartment predicted clinical and symptomatic instability as translation was posterior to positions achieved in normal knees during the active and passive flexion arc. A Lachman sign can be produced in a closed magnet with different methods and findings can be used for more precise information regarding kinematics and degree of instability and could be helpful if surgical treatment is necessary.

Knee Isometric Torque and Electromyographic Specificities After Semitendinosus and Gracilis Hamstrings Anterior Cruciate Ligament Reconstruction

Because the co-contraction of the gastrocnemius and hamstring muscles strains the anterior cruciate ligament, the role of the gastrocnemius muscle is of particular importance after semitendinosus and gracilis tendon autografts for anterior cruciate ligament reconstruction. This study aimed to examine the neuromuscular mechanisms underlying postsurgical torque deficits during knee flexion by using surface electromyography. A total of 14 volunteer patients (eight men, six women; age, 32.5 +/- 9.3 yrs; height, 172.7 +/- 6 cm; weight, 69.6 +/- 10.2 kg) were enrolled in the study; all had undergone anterior cruciate ligament reconstruction performed by the same surgeon. The neuromuscular mechanisms were assessed using isometric tests and surface electromyographic recordings at 19 mos post-reconstruction. The torque deficits in the injured knee were compared with the uninjured knee, which served as control values. Significant differences in torque production were observed between the two limbs at specific angular positions during the extension and flexion tests (P < 0.05). The difference in the root mean square myoelectrical activity between the limbs was computed at each tested position, revealing that the gastrocnemius muscle had greater activity at 75 degrees than at 45 degrees (P < 0.05). In deep flexion (>70 degrees), the gastrocnemius muscle may compensate for the weakened hamstrings and thereby strain the anterior cruciate ligament graft after anterior cruciate ligament semitendinosus and gracilis tendon reconstruction.

Anatomic Reconstructive Surgery for Posterolateral Instability of the Knee

We describe an anatomic reconstructive surgical procedure that simultaneously reconstructs the fibular collateral ligament, popliteal tendon, and popliteofibular ligament using split Achilles allograft, and compare the clinical results of this technique with those of the posterolateral corner sling procedure for posterolateral instability of the knee. Case series. Forty-six patients were treated for posterolateral instability of the knee between 1998 and 2002. The posterolateral corner sling procedure was performed in 25 patients (group A) and anatomic reconstructive surgery in 21 patients (group B). The minimum follow-up was 12 months. In all cases, arthroscopic evaluation was performed. Clinical review included the Lysholm knee scores and varus laxity and tibial external rotation assessment. The mean Lysholm knee scores were 54.8 points in group A and 54.4 points in group B before surgery, and 86.9 and 93.6 points at the time of the latest follow-up, respectively (P < .05). Tibial external rotation of 5 degrees more than the contralateral uninjured knee was present in 12% of group A and in 5% of group B (P < .05). Varus laxity of 5 mm greater than the contralateral knee was observed in 28% of group A and in 14% of group B (P < .05). Anatomic reconstruction of the posterolateral corner resulted in less varus laxity and tibial external rotation than did the posterolateral corner sling procedure. Type IV, case series, no or historical control group.

Using neural networks to understand relationships in the traction of studded footwear on sports surfaces

The purpose of this study was to determine whether mechanical adaptations were present in patients with anterior cruciate ligament (ACL)-deficient knees during high-demand activities. Twenty-two subjects with unilateral ACL deficiency (11 males and 11 females, 19.6 months after injury) performed five different activities at a comfortable speed (level walking, ascending and descending steps, jogging, jogging to a 90-degree side cutting toward the opposite direction of the tested side). Three-dimensional knee kinematics for the ACL-deficient knees and uninjured contralateral knees were evaluated using the Point Cluster Technique. There was no significant difference in knee flexion angle, but an offset toward the knee in less valgus and more external tibial rotation was observed in the ACL-deficient knee. The tendency was more obvious in high demand motions, and a significant difference was clearly observed in the side cutting motions. These motion patterns, with the knee in less valgus and more external tibial rotation, are proposed to be an adaptive movement to avoid pivot shift dynamically, and reveal evidence in support of a dynamic adaptive motion occurring in ACL-deficient knees.

New algorithm for selecting meniscal allografts that best match the size and shape of the damaged meniscus

Procedures used by tissue banks in selecting meniscal allografts that will best restore normal contact pressure at the time of surgical implantation into a recipient's knee should be improved. Our objective was to develop regression equations that use dimensions measured from magnetic resonance (MR) images of the contralateral knee to predict values of important meniscal parameters of the injured knee. Another objective was to incorporate these equations into an algorithm for selecting allografts that best match the size and shape of the damaged meniscus (either medial or lateral). In each of 10 knee specimens, four transverse and six cross-sectional parameters of the medial and lateral menisci were quantified from measurements obtained using a laser-based, noncontacting, 3-D coordinate digitizing system. In each of 10 contralateral knee specimens, six transverse and 24 cross-sectional (i.e., perpendicular to transverse plane) dimensions were measured for the medial and lateral menisci from MR images of each knee specimen. Simple linear regression equations related these 10 parameters to each of 38 predictor variables determined from magnetic resonance imaging (MRI) dimensions and the best regression equation for each parameter was identified. Requiring only 9 of the 30 dimensions as predictor variables, the best regression equations predicted 8 of 10 and 10 of 10 medial and lateral menisci parameters, respectively, with R2 values>0.500. The algorithm for selecting meniscal allografts involves: collecting an inventory of meniscal allografts and determining the 10 meniscus parameter values for all allografts in the inventory; measuring the dimensions as required from MRI scans of the uninjured knee; using the dimensions as inputs to the regression equations to predict values of meniscal parameters; and selecting the meniscal allograft from the inventory that best matches the predicted values of meniscal parameters. Selecting meniscal allografts using our new algorithm may enable allografts to better meet the clinical objectives of meniscal transplantation, which are to reduce pain in some patients following meniscal resection and to inhibit the degeneration of the articular cartilage.

Anatomic Reconstructive Surgery of the Posterolateral Instability of the Knee Using Split Acilles Allograft

Purpose : This paper describes a new anatomic reconstructive surgical procedure that simultaneously reconstructs the fibular collateral ligament, popliteal tendon and popliteofibular ligament using a split Achilles allograft and compares the clinical results of this new technique with the posterolateral corner sling procedure used for posterolateral instability of the knee. Materials and Methods: Forty-six patients were treated for a posterolateral instability of the knee between 1998 and 2003. The posterolateral corner sling procedure (Group A) was performed in 25 patients and anatomic reconstructive surgery (Group B) in 21 patients. The minimum follow-up was 12 months. An arthroscopic evaluation was performed in all cases. The clinical review included the Lysholm knee scores as well as a lateral instability and tibial external rotation assessment. Results : The mean Lysholm knee scores in groups A and B were 54.8 points and 54.4 points prior to surgery, and 86.9 and 93.6 points at the time of the latest follow-up, respectively (p＜0.05). Tibial external rotation of 5 degrees more than the contralateral uninjured knee was noted in 12% of group A and in 5% of group B (p＜0.05). Lateral instability of 5 mm greater than the contralateral knee was observed in 28% of group A and in 14% of group B (p＜0.05). Conclusion : Anatomic reconstruction of the posterolateral corner resulted in less lateral instability and tibial external rotation than did the posterolateral corner sling procedure.

Altered knee kinematics in ACL‐deficient non‐copers: A comparison using dynamic MRI

Kinematics measured during a short arc quadriceps knee extension exercise were compared in the knees of functionally unstable ACL-deficient patients, these patients' uninjured knees, and uninjured control subjects' knees. Cine phase contrast dynamic magnetic resonance imaging, in combination with a model-based tracking algorithm developed by the authors, was used to measure tibiofemoral kinematics as the subjects performed the active, supine posture knee extension exercise in the terminal 30 degrees of motion. Two determinants of tibiofemoral motion were measured: anterior/posterior location of the tibia relative to the femur, and axial rotation of the tibia relative to the femur. We hypothesized that more anterior tibial positioning, as well as differences in axial tibial rotation patterns, would be observed in ACL-deficient (ACL-D) knees when compared to uninjured knees. Multifactor ANOVA analyses were used to determine the dependence of the kinematic variables on (i) side (injured vs. uninjured, matched by subject in the control group), (ii) flexion angle measured at five-degree increments, and (iii) subject group (ACL-injured vs. control). Statistically significant anterior translation and external tibial rotation (screw home motion) accompanying knee extension were found. The ACL-D knees of the injured group exhibited significantly more anterior tibial positioning than the uninjured knees of these subjects (average difference over extension range=3.4+/-2.8 mm, p<0.01 at all angles compared), as well as the matched knees of the control subjects. There was a significant effect of interaction between side and subject group on A/P tibial position. We did not find significant differences in external tibial rotation associated with ACL deficiency. The changes to active joint kinematics documented in this entirely noninvasive study may contribute to cartilage degradation in ACL-D knees, and encourage more extensive investigations using similar methodology in the future.

Posterior Cruciate Ligament Reconstruction: Double-Loop Hamstring Tendon Autograft Versus Achilles Tendon Allograft—Clinical Results of a Minimum 2-Year Follow-up

The purpose of this study was to compare clinical results of arthroscopic posterior cruciate ligament (PCL) reconstructions using double-loop hamstring tendon autograft and Achilles tendon allograft while preserving the original PCL remnant. Case-control study of results of treatment. From September 1997 to December 2000, 36 patients who received only PCL reconstruction were reviewed retrospectively. Of these, 18 patients received autogenous double-loop hamstring tendon reconstruction (group I) and 18 received Achilles tendon allograft reconstruction (group II). The same PCL reconstruction procedure was performed in both groups. At final follow-up at a minimum of 2 years, patients were evaluated by 4 measures: the International Knee Documentation Committee (IKDC) evaluation, Lysholm knee scores, the posterior draw test, and Telos stress radiography. Between the 2 groups, preoperative demographic factors (age, gender, activity level, and mean duration to surgery) showed no statistically significant difference (P > .05). According to IKDC evaluation of group I, 16 of the 18 knees rated normal or nearly normal, whereas 2 fell into the abnormal category. By the same criteria, 14 of the 18 knees in group II were normal to nearly normal, 3 were abnormal, and 1 was severely abnormal. IKDC scores showed no statistical difference between the 2 groups (P = .98). Postoperative mean Lysholm knee scores were 90 points (range, 78-100) for group I and 85 (range, 70-95) for group II; improvements of 22 and 17 points, respectively. According to the Lysholm knee scores, group I showed slightly better results than did group II, with a statistical significance of P < .01. Telos stress radiography showed the mean difference in posterior translation between the injured and uninjured knees to be 2.2 mm (range, 0 to 7.0 mm) for group I and 2.9 mm (range, 1.0 to 7.0 mm) for group II. The Telos stress test showed no statistical difference between the 2 groups (P = .14). The clinical outcome was the same for both groups. Despite its comparatively short length and small diameter, the double-loop hamstring tendon autograft was as good as Achilles tendon allograft in PCL reconstruction. Level III, case-control study.

Medial Collateral Ligament Stiffness In Males And Females

The Medial Collateral Ligament (MCL) is the most commonly injured ligament in the knee joint. In sports medicine, concern exists regarding ligament stiffness and structure and the differences between males and females. Research has shown gender differences in the stiffness of the anterior cruciate ligament but little attention has been given to the differences in the genders regarding the tensile strength of the MCL. PURPOSE To compare the force/strain curve and resultant slope of the MCL in uninjured knees and determine if there is a difference in males and females. METHODS Forty-five healthy volunteers (26 females and 19 males; height = 170.6 ± 7.75 cm; weight = 74.2 ± 15.14 kg; age = 23.2 ± 3.96 years) with no history of knee surgery or knee injury in the past six months were tested on a multipurpose arthrometer device. A coin toss determined which knee would receive a valgus force of 100–120 Newtons first. The force was applied to the lateral aspect of the knee in full extension. Slope comparisons were analyzed using ANOVA with repeated measures. RESULTS There was a significant difference in the slope of the force/strain curve between genders (F1,43 = 10.84, p = .002). The resultant slopes of male MCLs were significantly stiffer than females in extension: the mean slope for males with the knee in full extension was 20.29 and for females it was 17.79. When weight and height were added as covariates, there was still a statistical difference between the genders (F1,43 = 8.01, p = .007). CONCLUSIONS There is a difference in the stiffness, as measured with a force/strain curve and resultant slope, between the Medial Collateral Ligaments in males and females.

Medial Collateral Ligament Stiffness In Males And Females

The Medial Collateral Ligament (MCL) is the most commonly injured ligament in the knee joint. In sports medicine, concern exists regarding ligament stiffness and structure and the differences between males and females. Research has shown gender differences in the stiffness of the anterior cruciate ligament but little attention has been given to the differences in the genders regarding the tensile strength of the MCL. PURPOSE To compare the force/strain curve and resultant slope of the MCL in uninjured knees and determine if there is a difference in males and females. METHODS Forty-five healthy volunteers (26 females and 19 males; height = 170.6 ± 7.75 cm; weight = 74.2 ± 15.14 kg; age = 23.2 ± 3.96 years) with no history of knee surgery or knee injury in the past six months were tested on a multipurpose arthrometer device. A coin toss determined which knee would receive a valgus force of 100–120 Newtons first. The force was applied to the lateral aspect of the knee in full extension. Slope comparisons were analyzed using ANOVA with repeated measures. RESULTS There was a significant difference in the slope of the force/strain curve between genders (F1,43 = 10.84, p = .002). The resultant slopes of male MCLs were significantly stiffer than females in extension: the mean slope for males with the knee in full extension was 20.29 and for females it was 17.79. When weight and height were added as covariates, there was still a statistical difference between the genders (F1,43 = 8.01, p = .007). CONCLUSIONS There is a difference in the stiffness, as measured with a force/strain curve and resultant slope, between the Medial Collateral Ligaments in males and females.

Knee Osteoarthritis

Abstract More than 20 million Americans have osteoarthritis (OA), which affects the knee more often than any other joint and is the most common cause of long-term disability in persons older than 65 years. Knee OA is common, particularly in older patients and especially the obese. Knee injury, depending on the severity and type, can increase the risk of developing and the rate of progression of OA. In assessing impairment for knee OA, the evaluator must obtain a thorough history and physical examination and identify all potential risk factors. To opine that an injury caused OA, the evaluator should demonstrate that the traumatized knee shows significant arthritis but that the contralateral uninjured knee is radiographically normal; for an evaluator to suggest that pre-existing arthritis was aggravated, the involved knee should show significantly more advanced OA than the contralateral joint. Joint space widths (cartilage intervals) of both knees must be measured carefully on anteroposterior films obtained standing with a film-to-camera distance of 90 cm (36 in) and the beam at the level of and parallel to the joint surface. Taking into account all of the data (history, physical findings, and radiographic measurements from both the involved and contralateral joint), the rating physician can assess causation, estimate impairment, and apportion the latter to one or more etiologies.