Introduction: Recent data suggests that Double Bundle ACL reconstruction is bio-mechanically and potentially clinically superior. The success of Doudle bundle ACL reconstruction is dependent on tunnel placement. Of clinical concern is the increased technical difficulty and the potential for complications. The aim of our study was to determine how big the learning curve was for a high volume ACL Surgeon.

Methods: Ten Double bundle ACL reconstruction procedures were carried out on suitable individuals. Following the procedure all patients underwent a CT scan of the relevant knee. Femoral tunnel placement was measured according to the quadrant technique described by Bernard and Hertel. The ideal tunnel locations used for analysis were those described by Zantop et al. On the tibial side, the radiographic measurements were performed according to Staubli and Rauschning. The centres of the AM and PL bundles were expressed as percentages of the maximum tibial sagittal diameter. The tibial ACL attachment at the centre of the AM bundle was taken to be 30% of the maximal tibial diameter and the centre of the PL bundle was located at 44%.

The tunnel positions were measured for each patient.

Results: Good tunnel placement was achieved in the majority of patients. There was an initial learning curve with improvement in tunnel placement as experience increased. Femoral tunnel positions had the greatest variation. There were no complications. The technical challenges are discussed.

Conclusion: We have shown that it is possible for a high volume ACL surgeon to convert from a single bundle reconstruction technique to a double bundle reconstruction with relative accuracy.

The purpose of this study was to characterise the neuromuscular patterns associated with different severities of knee osteoarthritis (OA).

Forty-five patients with moderate OA, thirty-seven with severe OA and thirty-eight asymptomatic controls underwent a complete gait analysis with only the electromyographic (EMG) findings presented in this abstract. Severity levels were established through the Kellgren-Lawrence radiographic grading system, functional ability, and those classified with severe OA were tested within one-week of total knee replacement surgery. All OA patients had medial joint involvement. Subjects walked along a five-meter walkway a total of five times at a self- selected walking speed. Muscle activation patterns of the vastus medialis and lateralis, medial and lateral hamstring and medial and lateral gastrocnemius were recorded and normalised to maximum voluntary isometric contractions. All EMG waveforms were analyzed for group differences using PCA [1] followed by an ANOVA (group by muscle) for the PCA scores for each muscle group. These scores reflect both magnitude and shape changes.

The control group was significantly younger (53.3 ±9.5 yrs) and lighter (77.5 ±14.5 Kg) than the patient groups (Moderate =59.8 ±8.0 years and 94.2 ±19.2 Kg and Severe = 63.1 ±7.9 yrs and 95.8 ±14.6Kg). The severe OA group walked significantly slower (0.9 ±0.2 m/s) than the asymptomatic (1.3 ±0.1) m/s) and the moderate OA (1.2 ±0.2 m/s) groups. The PCA analysis of the EMG waveforms revealed statistically significant differences (P< 0.05) in patterns among the three groups and between muscles within the three muscle groups tested.

The neuromuscular differences found among groups during gait demonstrate that the role of the musculature surrounding the knee is altered slightly in those with moderate OA and altered drastically in those with end-stage OA compared to asymptomatic subjects, reflecting a progression. The differences are consistent with the severe group adopting a co-activation strategy of agonist and antagonists, more lateral activation and a reduction in plantar flexion during push off. These are consistent with strategies to increase dynamic stability and reduce medial joint loading. The moderate OA group illustrates a trend toward adopting this pattern but with only very subtle differences from asymptomatic subjects as has been previously reported. These neuromuscular alterations have implications with respect to muscle function and may assist in defining severity.

The purpose of this study was two-fold:

to examine perioperative prospective changes in pain, disability and psychosocial variables in ACL reconstructed recreational athletes over the pre-op to eight week post-op period.

All participants were recreational athletes at the time of their injuries who had patella-autograft procedure at the the Queen Elizabeth II Health Sciences Centre. Fifty-four patients (twenty-nine males; mean age = 25.4 years, SD = 8.08). Mean education was fourteen years (SD = 2.08), 32%(17) were married, 67%(36) single, and 1% was divorced. 94%(51) of the sample was Caucasian, 3%(2) Black, and 1% Asian. One quarter reported their ACL injury was due to sport-based contact, with non-contact sporting activity reported at 76%(41). All participants completed measures of pain, depression, pain catastrophizing, state anxiety pre-op, on days one and two following surgery and again at eight weeks post-op. Disability was assessed pre-op and eight weeks post-op.

Pain was varied across comparisons with preoperative pain increased twenty-four and forty-eight-hour post-op. Pain at forty-eight-hours postoperative was significantly higher than pain reported at eight-weeks post-op. Catastrophizing did not differ from the pre-op to twenty-four-hour post-op but did drop from twenty-four to forty-eight-hours and forty-eight-hours to eight-weeks post-op. Pre-op depression increased twenty-four-hour post-op, but not from twenty-four to forty-eight-hours and declined at eight-weeks. Anxiety increase pre-op to twenty-four-hours but not from twenty-four to forty-eight-hours but did drop from forty-eight-hours to eight-weeks.Disability did not change over time. Regression showed age or gender did not predict disability but forty-eight hour pain and catastrophizing did.

These data indicate that pain and psychological variables change over time of ACL recovery. Results suggest that pain and distress peek during acute post-op period. As well, post-op catastrophizing predicts disability at eight weeks post-op which may indicate that catastrophizing may be related to behaviours related to slower recovery following ACL reconstructive surgery.

The knee adduction moment is indicative of the degree of medial compartmental loading at the knee joint and has been related to the presence and progression of knee osteoarthritis (OA). Studies have reported differences between OA and asymptomatic groups when measuring the adduction moment at the knee; however, there have been various biomechanical models used to describe this moment. In addition, non-invasive interventions have been shown to decrease the adduction moment but only at certain portions of the gait cycle. The objective of the study was to determine if changing the biomechanical model would affect the ability to detect differences between OA and asymptomatic gait and whether these differences depended on which portion of the gait cycle was analysed.

The gait of forty-four asymptomatic and forty-four moderate OA subjects was measured. The adduction moment was calculated using three different biomechanical models commonly used in the literature:

a 2D representation of the lower limb,

The choice of biomechanical model changed the overall magnitude and shape of the adduction moment waveform. These changes affected the ability to detect group differences using commonly reported parameters of the adduction moment. However, group separation was achieved (regardless of model) when analyzing the overall magnitude of the adduction moment across stance phase and the mid-stance portion of the gait cycle.

These results demonstrate that the OA subjects are not unloading the medial compartment of the knee at full weight acceptance as well as the healthy controls. Furthermore, the OA subjects are experiencing a higher medial compartment load that is being sustained for the duration of the stance phase of the gait cycle. Group differences that are not model dependent may be important in understanding the pathomechanics of OA and evaluating interventions. These findings support the need for a better understanding of the anatomical mechanisms associated with the adduction moment.

Determine the association between net external knee adduction moment (KAM) characteristics and foot progression angle (FPA) in asymptomatic individuals and those with moderate and severe osteoarthritis through discrete variable and principal component analysis (PCA).

Fifty-nine asymptomatic (age 52 ± 10 years), fifty-five with moderate knee OA (age 60 ± 9 years) and sixty-one individuals with severe knee OA (age 67 ± 8 years, tested within one week of total knee replacement surgery) participated. Three-dimensional (3D) motion (Optotrak) and ground reaction force (AMTI) data were recorded during gait. Subjects walked at a self-selected velocity. The KAM, calculated using inverse dynamics was time normalised to one complete gait cycle. FPA was calculated using stance phase kinematic gait variables. The discrete variable, peak KAM, was extracted for the interval (30–60%) of the gait cycle. PCA was used to extract the predominant waveform features (Principal Components (PC)) of which PC-Scores were computed for each original waveform. Pearson Product Moment Correlations were calculated for the FPA and both the PC-scores and peak KAM. Alpha of 0.05 used to test significance.

No significant correlations were noted for the groups between peak KAM and the FPA, or for the first PC-Scores (PC1) of which captured the original KAM waveforms overall magnitude and shape. The second PC (PC2) captured the shape and magnitude during the second interval of stance (30–60%) with respect to the first. Correlations of FPA to PC2 were significant for the asymptomatic group(r=−0.40, p=0.002) and the moderate OA group (r=−0.32, p=0.017) but not for the severe group(r=−0.13, p=0.316).

No relationship between FPA and peak KAM was found across the groups using discrete variable analysis despite reports of associations in asymptomatic subjects. The PCA results suggest a toe out FPA was moderately correlated to a decreased KAM during 30–60% of the gait cycle for asymptomatic and moderate OA individuals only. These individuals respond to a toe out progression angle, altering the KAM which directly affects medial knee compartment loading, where those with severe OA do not.

Modern gait analysis offers a unique means to measure the biomechanical response to diseases of the musculoskeletal system during activities of daily living. The objective of this on-going study is to quantify the biomechanical environment of the knee joint in subjects with moderate knee osteoarthritis (OA). We collected 3-D motion, ground reaction force, and electromyographic data from seven normal subjects and five subjects with moderate knee OA. There were no differences in stride characteristics or joint motion patterns between the two groups. In contrast, we found differences in knee joint kinetics between the moderate OA subjects and the normal control subjects.

The objective of this on-going study is to quantify the biomechanical environment of the knee joint in subjects with moderate knee osteoarthritis (OA). Our goal is to identify biomechanical characteristics related to treatment interventions.

The moderate knee OA patients walked with a visibly normal gait as measured by stride characteristics and joint angles. Differences were detected in the joint loading (ie adduction and flexion moments).

The biomechanical differences between normal and osteoarthritic knees will provide the basis upon which to design and evaluate non-invasive treatments for knee OA.

Subjects performed, in random order, five trials of their normal selected speed, and a fast walk (150% of the normal speed). Three-dimensional motion and force data were used to calculate three dimensional joint angles, moments and forces.

There were no differences in stride characteristics (walking speeds, stride lengths, or stride times) between the two groups. The moderate OA patients walked with normal knee joint motion patterns. In contrast, we found differences in knee joint kinetics between the moderate OA subjects and the normal control subjects. The magnitude of the adduction moment during stance was larger for the moderate OA patients at both walking speeds (p< 0.05). We also identified differences in the pattern of the flexion moment, but only at the higher walking speed (p< 0.05).

Gait analysis can provide insight into the mechanical factors of knee osteoarthritis by quantifying the dynamic loading and alignment of the knee during activities of daily living

Shoulder Arthroscopy techniques may pose surgical risk to vascular structures that may cause active bleeding during surgery. The vascularity of the subacromial structures showed constant patterns of distribution and specific sources of bleeding were analyzed. Knowledge of the vascular anatomy may decrease the bleeding during subacromial arthroscopy surgery.

Shoulder Arthroscopy techniques may pose surgical risk to vascular structures that may cause active bleeding during surgery. A detailed anatomy map of frequent sources of bleeding is more than desired in order to properly identify these bleeding points, and avoid the unnecessary overuse of thermal tools and pressure pumps to control the hemorrhage.

Our purpose is to study the vascular anatomy of the subacromial space, and to map the major sources of expected bleeding during subacromial arthroscopy surgery.

Ten shoulders of five adult cadavers underwent whole body arterial perfusion with a mixture of lead oxide, gelatin and water. The shoulders were dissected, photographed, tissue specimens were radio graphed, scanned and analyzed with a digital software analyzer. Careful dissection of the different arteries of the subacromial bursa, and anatomic landmarks of the walls were documented. Correlations of bleeding areas during subacromial arthroscopic surgery and cadaver dissection were carried out. A vascular map of the bursa was created.

The vascularity of the subacromial structures showed constant patterns of distribution and specific sources of bleeding were analyzed. We divided this space into walls with their major arteries as follows: Anterior wall: Acromial branch of the thoracoacromial artery. Posterior wall: Acromial branch of the suprascapular artery. Medial wall: Anterior and posterior Arteries of the AC joint. Lateral wall: No major arteries identified. Vascularity of the roof and floor is also described.

The subacromial space is highly vascular. Knowledge of the vascular anatomy may decrease the bleeding during subacromial arthroscopy surgery.

Prospective analysis of a homogeneous group of ninety-two well-trained runners quantified injury parameters in relation to objective gait measurements. A negative correlation was found between peak tibial acceleration and magnitude of rearfoot motion for specific injury locations, suggesting that objective biomechanical parameters may be implicated in, or conversely, may be predictive of running injury. Gait as a predictor of specific running injury may hold merit in the prevention of running related injuries and the industry of athletic footwear design.

The purpose of this study was to determine the relationship between rearfoot motion and shock attenuation during running and their link to injury in trained runners.

Rearfoot motion appears to affect shock transmission through the tibia in athletes sustaining specific injuries.

Objective biomechanical parameters may be implicated, or conversely, may be predictive of running injury. This relationship has implications in the industry of shoe design and the prevention of running related injuries.

Injury rate during the one-year study period was 52%. Injury to the lower leg (e.g. shin splints, stress fracture) was the most common, comprising 22.7% of all injuries. A negative correlation was found between peak tibial acceleration and magnitude of rearfoot motion in several injury groups (r2=0.35–0.65), suggesting a biomechanical mechanism influencing impact forces. Such a mechanism was not apparent in athletes not demonstrating injury (r2=0.00).

Ninety-two well-trained, intercollegiate running athletes (forty women, fifty-two men) were prospectively monitored through biomechanical analysis, survey data, daily log and physician assessment. Subjects ran on a treadmill at 3.8m/s in a fatigued state. Rearfoot motion was assessed via coronal plane video (60Hz). Shock transmission at the tibia was measured using uniaxial accelerometers (1000Hz). Athletes reported injury, location and associated factors. A CASM qualified physician corroborated diagnosis. Outcome measures included the occurrence of a running related injury affecting the athlete’s ability to train or compete, frequency of injury location and diagnosis. Peak tibial acceleration and average range of rearfoot motion were quantified for each athlete. Pearson product moment determined correlation between biomechanical variables according to injury location.

Funding: A research grant was provided by the Nike Sport Research Laboratory, Beaverton, Oregon

Purpose: To establish and validate animal model for Achilles tendon disease with subsequent examination of histology, biochemistry and biomechanics

Methods: Experimental rats were subjected to an over-exercise running regime. Achilles tendons were analyzed for histology, glycosaminoglycan content, collagen content, collagen subtype, collagen cross-linking (hydrothermal isometric tension testing), and mechanical properties.

Results: Experimental rat Achilles tendons demonstrated: decreased semi-quantitative grade for collagen organization (2.9 vs. 3.7, p < 0.05), decreased semi-quantitative grade for collagen staining (1.9 vs 3.5, p < 0.05) and increased nuclear numbers per high-power field (527 vs. 392, p < 0.05). Immunohistochemical analysis revealed a predominance of by fibroblasts or endothelial cells. The total collagen content remained unchanged (84.3 vs. 89.0% p=0.38), while the glycosaminoglycan content was increased (17.5 vs. 9.0% p=0.02). Differences in collagen cross-linking were characterized by a greater proportion of reducible intrahelical crosslinks. These differences did not translate into a decrease in ultimate tensile failure during mechanical testing (UTS of 77.8 vs. 88.8 N, p=0.26).

Conclusions: Over-exercise model produced Achilles tendons with histology and biochemistry consistent with the animal and human tendon disease and characteristic of a remodeling response not an inflammatory response.

Purpose: The use of allografts for anterior cruciate ligament (ACL) reconstruction has gained increased popularity. The major benefits of allograft for ACL replacement include decreased morbidity, easier patient rehabilitation and include ease of surgical procedure, decreased harvest site morbidity and easier patient rehabilitation. Further, allografts have improved appeal because of better sterilization techniques, improve graft availability and decreased hospital costs.|The objective of this study was to perform mechanical testing on various types of allograft. Specimens for allograft reconstruction of the anterior cruciate ligament included tibialis anterior tendon, tibialis posterior tendon, Achilles tendon and bone patella tendon tissues

Methods: The allografts tested were used for deployment in patients suffering with anterior cruciate ligament disruptions. A total of fifty grafts were analyzed. The breakdown of graft types included 15 tibialis anterior tendon, 15 tibialis posterior tendon, 10 Achilles tendon and 10 bone patella tendon tissues. The test techniques included: cutting the tendons to a set thickness and length. The tendons were then mounted in a cryogrip and frozen with liquid Nitrogen to below zero. They were mounted into a servo-hydraulic testing machine and pre-loaded and pre-conditioned. The specimens were then stretched to failure at a set strain rate.

Results: No difference was found between the mechanical/material properties of the various tendon allografts – these included tensile strength and a high stress linear modulus assessments. The mechanical (structural properties) of the allografts were more dependant on the cross sectional area of the allograft than the type of allograft tissue.The greater the cross-sectional area of the allograft, the greater the strength and stiffness of the graft.

Conclusions: These findings have considerable clinical applicability in choosing an allograft for anterior cruciate ligament reconstruction.

Spinal stabilization through appropriate neuromuscular responses to external perturbations is important in the prevention and rehabilitation of low back pain (LBP). Muscle synergism, coordination and imbalances are terms used to describe the neuromuscular strategies considered important to actively maintain spinal stability. We recorded surface electromyographic (EMG) recordings from healthy controls (CON) and those with chronic, mechanical low back pain during performance of an exercise model that dynamically challenged lumbar-pelvic stability. Those with LBP showed greater variation in amplitude in response to the perturbations imposed by the exercise model, and demonstrated a lack of synergistic and antagonistic coactivation compared to the CON group.

The purpose of this study was to compare the neuromuscular control strategies used by those with LBP and those without to complete a standardized task aimed at dynamically challenging stability of the lumbar spine and pelvis.

Those with LBP activated their muscles in a more asynchronous manner than normal controls, illustrating an alteration in neuromuscular control that should be a focus of therapeutic intervention strategies aimed at prevention and rehabilitation of LBP.

These data illustrate a need for neuromuscular retraining, focusing on muscle coactivation in response to dynamic perturbations rather than a single perturbation.

Surface EMG recordings from two trunk extensor and five abdominal muscle sites were recorded from twenty-four men without LBP and fourteen men with chronic LBP while they performed a task that dynamically challenged lumbar spine and pelvis stability. The EMG amplitudes recorded from the upper and lower rectus abdominus sites were significantly (p< 0.05) lower for the LBP compared to the CON group. The temporal EMG profiles were compared using a statistical pattern recognition technique. This analysis showed that the LBP group used different patterns of synergistic muscle coactivity compared to the highly coordinated manner in which all seven muscles were recruited for the CON.

These results quantify the neuromuscular control differences between the two groups providing a foundation for developing an objective classifier of neuromuscular control impairments associated with LBP. In future this approach could assist in directing therapeutic interventions in particular those aimed at muscle reeducation.

The objective of this study was to determine if abnormal neuromuscular patterns exist in individuals with knee Osteoarthritis compared to those with healthy knees. We collected surface electromyographic signals during preferred speed and fast walk conditions from seven muscles crossing the knee joint. We found differences between the two groups that could lead to differences in joint loading, with the OA group having higher coactivity between hamstrings and quadriceps during initial loading. Further investigating these differences is warranted in particular given the trend for lower external extensor moments for the OA group at the fast walking speed.

The purpose of this study was to compare neuromuscular control of knee joint motion during walking between those with moderate Osteoarthritis (OA) and those with healthy knees (CON).

Moderate OA neuromuscular control patterns differed from those with healthy knees.

Detecting neuromuscular alteration associated with mild to moderate knee OA is important to direct therapeutic strategies aimed to slow down or possibly reverse disease progression.

Surface electromyographic (EMG) recordings were collected from seven muscles crossing the knee joint of CON (n=7) and those with moderate OA (n=4) during preferred speed and a fast-paced walks. A pattern recognition technique was applied to the EMG profiles. No differences (> 0.05) were reported between the two groups for spatial and temporal gait parameters or knee joint kinematics. Statistical differences were found (p< 0.05) in muscle activation patterns between the two groups and the differences were more prominent at the faster walking speed. The two vasti muscles had double peaks during stance and higher amplitudes at heel strike for the OA group. There was higher activity in the two hamstring muscles at heel contact and a burst of activity during late stance for the OA group.

The disproportionately higher knee flexor coactivity at heel strike may reflect a guarded response to pain, whereas the burst during weight transfer may reflect a stabilizing response as the knee moment changes from a flexor to an extensor moment. At normal walking speeds the neuromuscular control patterns were similar between groups, but differences were exaggerated when the system was stressed at higher speed.

Tendon disease causes widespread morbidity ranging from mild pain to catastrophic end-stage rupture. The pathophysiology of tendon disease is not certain. An overuse exercise model was developed using rats with the aim of developing tissue with histological, biochemical and biomechanical features similar to those in human tendinosis. Results indicate that the biological response to over-exercise of the rat Achilles tendon is similar to the literature description of pathological specimens of human with disease. Biochemical and histological analysis of the rat Achilles tendons suggest that the patho-physiology is more consistent with a repair response than with a classical inflammatory response.

Tendon disease causes widespread morbidity ranging from mild pain to catastrophic end-stage rupture and the pathophysiology of tendon disease is not certain.

To develop an overuse exercise animal model to study the pathophysiology of Achilles tendon disease.

Experimental rats were subjected to an over-exercise running regime, while control rats were maintained under normal cage activity. Achilles tendons were analyzed for histological features, glycosaminoglycan content, collagen content, collagen subtype, collagen crosslinking (hydrothermal isometric tension testing), and mechanical properties.

Experimental rat Achilles tendons demonstrated: increased nuclear numbers per high-power field (527 vs. 392, p < 0.05), decreased semi-quantitative grade for collagen organization (2.9 vs. 3.7, p < 0.05) and decreased semi-quantitative grade for collagen staining (1.9 vs 3.5, p < 0.05). The total collagen content remained unchanged (84.3 vs. 89.0% p=0.38), while the glycosaminoglycan content was increased (17.5 vs. 9.0% p=0.02). Increased levels of collagen type III were not demonstrated, however. Experimental tendons were determined to have distinct differences in the collagen crosslinking patterns, with reduced total cross links and a greater population of immature, hydrolytically unstable cross links. These differences did not, however, translate into a decrease in ultimate tensile failure during mechanical testing (UTS of 77.8 vs. 88.8 N, p=0.26).

The histology and biochemistry observed in the experimental rat Achilles tendons were similar to those described in the literature on human Achilles tendon disease.

The rat Achilles tendon over-exercise model has demonstrated histopathology that was different from a control group and was consistent with the human literature for Achilles tendon disease.

Research Grants were received from the following organizations:

Canadian Orthopaedics Foundation