Projects - K-Lab ::

Projects

Foot & Ankle | Footwear | Hamstring
Injury Prevention | OA | Therapeutic Interventions
Affiliated Projects

Therapeutic Interventions

Current Projects

Total Ankle Replacements

The purpose of this study is to examine the differences in lower extremity kinematics and kinetics between three different total ankle replacements. Subjects will be recruited from the clinical populations of Dr. Nunley, Dr. Easley, and Dr. DeOrio within the Division of Orthopaedic Surgery. Each subject will be asked to come in for testing pre-operatively in order to assess their gait mechanics. In addition to their pre-operative visit, each subject will be asked to return one year and two years following their ankle replacement.

During the gait analysis portion of the study, each subject will be asked to complete a series of walking trials in which they will first be asked to walk at a self-selected comfortable speed. In addition, they will be asked to walk at a standard speed of 1.3 m/s. Static balance will also be assessed by having each subject complete a series of balance tasks starting with standing with their feet shoulder width apart followed by standing with their feet together, then in a semi-tandem stance with their surgical foot as their back leg and the heel of the contralateral foot in line with the toe of the surgical foot, and finally a tandem stance in which the heel of the non-surgical foot will be directly in front of the surgical foot. Each of these balance tasks will be completed 3 times for 10 seconds each. The next task will be a timed sit-to-stand task. In this task, subjects will be asked to sit down and stand up 5 times as fast as they can. Both the time it takes to complete the task as well as the lower extremity kinematics and kinetics will be recorded. The final task is a four square step test. During this test, subjects will be asked to step forward to the right, back, then to the left and then reverse the order. This task will also be timed and lower extremity kinematics will be recorded. The testing order will be randomized for each subject. However, during the balance tasks, those will be completed in order of difficulty starting with standing with feel shoulder width apart and moving to the tandem standing. If subjects are unable to make the entire 10 seconds, the time they can stand in the position unassisted will be recorded. In addition, if subjects are unable to complete a task pre-operatively this will be noted and they will be allowed to try all of the tasks again following surgical intervention.

The same procedure will be repeated for all subsequent visits at which time the testing order will again be randomized. All testing will be completed barefoot in order to avoid changed in ground reaction forces that can result from differences in footwear.

Current Status:

Currently 114 subjects have been tested pre-operatively with approximately 25 subjects having also completed their 1 year follow-up testing. Preoperative patients are still being recruited for this study and data collection is continuing.

Publication Status:

Abstracts:

Robin M. Queen, Alicia N. Abbey, Mark E Easley, James K DeOrio, James A. Nunley. Improvement in Ankle Kinetics and Kinematics after Total Ankle Replacement in Patients with Hindfoot Deformity. American Orthopaedic Foot and Ankle Society Annual Meeting, Vancouver, BC, 2009 (In Review)

Hip Replacement versus Hip Resurfacing

The aim of this study is to assess functional changes in gait, strength and range of motion in highly functional, active patients after hip resurfacing versus total hip arthroplasty in comparison to normal patients. In addition to monitoring post-operative strength and gait parameters, this study will examine various patient specific factors, such as perception of pain, hip range of motion (ROM), self-reported physical function and post operative complications to determine if any of these variables significantly influence post-operative gait and strength parameters.

The objective of this project is to study lower extremity kinetics and kinematics during walking and running gait as well as the overall function of patients who have had hip resurfacing arthroplasty in comparison to similar age, gender, height, weight, activity, and overall health status matched patients who were treated with total hip arthroplasty as well as health matched normal patients.. Twenty subjects will be recruited for each group from a database population maintained at Duke University by Dr. Vail. In addition, 20 healthy age, gender, height, weight, activity level, and overall health status matched controls will be recruited from the community surrounding Duke University. The WOMAC Osteoarthritis Index and the SF-36 will be used to assess pain and functional impairment due to osteoarthritis and general health status, respectively. The UCLA and Duke ASAP activity scores will be used to assess level of activity. Each subject will be asked to read and sign the informed consent approved by the institutional review board.

The subjects will be asked to participate in gait analysis studies both before surgery as well as 3 and 6 months after surgery. The studies will be conducted at the Michael W. Krzyzewski Human Performance Laboratory under the guidance of its director, Robin Queen, PhD. We will first have the subjects complete some clinically relevant function tasks. These tasks will include a sit-to-stand test and a timed get-up-and-go test. The time to complete the get-up-and-go test will be monitored using two sets of infrared photocells positioned along the walkway. In addition, hip flexion, extension, internal and external rotation as well as abduction and adduction range of motion will be recorded 3 times. Subjects will then be asked to wear form fitting shorts and shirts so as not to obstruct the view of the markers. 25 retro-reflective markers will be placed at the following anatomic landmarks: at the sacrum midway between the posterior iliac spines, bilaterally at the acromio-clavicular joint, lateral epicondyle, 50% of the distance between the radial and ulnar styloids, anterior superior iliac spines (ASIS), anterior portion of the thigh approximately 50% of the distance from the hip joint center to the knee joint center, lateral femoral condyle along the flexion-extension axis, anterior leg approximately 50% of the distance between the knee and ankle joint centers, lateral malleolus, posterior heel and the second webspace (toes). In addition, markers will be placed bilaterally at the medial femoral condyle as well as the medial malleolus during a standing trial. These markers comprise the Helen Hayes marker set and will be tracked using an 8 camera Motion Analysis system (Motion Analysis Inc, Santa Rosa, CA) sampling at 60 Hz. In addition, vertical, anterior/posterior, and medial/lateral forces as well as three dimensional moments will be obtained from a series of 4 force plates (AMTI, Watertown, MA) that are positioned in the walkway, collecting at 1200Hz.

Subjects will be asked to stand, for approximately 1 second, within the field of view of the cameras for a static standing trial to be collected. The trial will be used during data reduction to calculate knee and ankle joint centers. Once the standing trial has been collected the medial markers will be removed for the remainder of the trials. Subjects will be given 1 practice trial to become comfortable with each task and will then complete 7 acceptable trials of each movement task. An acceptable trial will be one in which the kinematic data are collected successfully and in which the subject contacts the force place correctly. Data collection should last approximately 60 minutes on three days, once before surgery and then at 3 and 6 months after surgery.

Subjects will first be asked to walk at a comfortable speed along the walkway while three-dimensional kinematics, kinetics, and walking speed are recorded. This information will be helpful in comparing the three groups on a simple task. The subjects will then be asked to complete two functional tasks that are more challenging. In the first task, subjects will be asked to run at a comfortable speed of at least 3.3m/s along the walkway as the same information is recorded. Finally the subjects will be asked to walk along the walkway, which will be covered with foam in order to determine how well subjects are able to walk on uneven surfaces. The same series of tasks will be completed pre-operatively as well as 3 months and 6 months post-operatively

Current Status:

Retrospective data collection has been completed and a manuscript will be prepared shortly. The patients for the prospective study are currently being recruited and tested.

Biceps Tenotomy versus Tenodesis: A Randomized, Prospective Study

The purpose of this study is to determine whether arthroscopic tenotomy or tenodesis of the long head of the biceps tendon has superior outcomes for subjective outcomes measurements, strength, and cosmetic appearance in patients treated for pathology of the long head of the biceps tendon. We hypothesize that biceps tenodesis will result in better outcomes based on subjective outcomes (American Shoulder and Elbow Society shoulder survey and SF-12), strength measurements for elbow flexion and forearm supination, and cosmetic appearance.

Degenerative changes, tears, and subluxation of the long head of the biceps tendon are common etiologies of pain at the anterior aspect of the shoulder. Current surgical techniques used to address biceps pathology refractory to conservative management include tenotomy and tenodesis of the long head of the biceps tendon. There are no randomized, prospective studies comparing the outcomes of tenotomy and tenodesis. One retrospective comparison exists in the literature, but otherwise surgeons generally rely on their own experiences in choosing to perform a tenotomy or tenodesis. A randomized, prospective study comparing these two treatments will be useful in determining which treatment, if any has superior clinical outcomes.

Patients greater than 18 years of age clinically identified as having tendonopathy of the long head of the biceps, which has failed to respond to conservative management, will be asked to take part in the study. Patients who consent to participate will complete three questionnaires: the American Shoulder and Elbow Society shoulder survey, the SF-12 questionnaire, and a questionnaire specific to this study. Patients will then undergo a diagnostic arthroscopy with biceps tenotomy versus biceps tenodesis (if biceps pathology is present at arthroscopy). At the time that the subject consents to participate in the study, one of these two options will randomly be chosen. A diagnostic arthroscopy is routinely performed when treating shoulder pathology and is the gold standard for confirming clinical diagnoses and subsequent appropriate treatment. Therefore, if there is no evidence of biceps pathology at the time of arthroscopy, neither a tenotomy nor a tenodesis will be performed and the patient will be removed from the study. All procedures will be done with arthrosopically-assisted techniques with three standard portals. The method of fixation for the tenodesis will be a bioabsorbable interference fit screw (Biotenodesis screw by Arthrex). This technique and device for biceps tenodesis are well described in the orthopaedic literature and are utilized at Duke on a regular basis by the participating surgeons.

Post-operatively, the patients will undergo routine care and physical therapy. The subjects will follow up in clinic as patients routinely do after surgery at two weeks, six weeks, three months, and four to six months. Additionally patients will be seen at one year and two years after surgery. There will be no charge for visits after the three month visit. At each of these visits the subjects will undergo a history and physical exam and complete the three questionnaires previously mentioned. Findings specifically documented on the physical exam will include presence or absence of a popeye deformity, active and passive range of motion for forearm supination and elbow flexion, and tenderness to palpation at either the site of the tenodesis or over the biceps muscle. (A “popeye” deformity is a bulge in the biceps muscle belly that can develop after a tenotomy as the biceps slides more distal.) At two years following surgery the subjects will undergo strength testing of the affected and unaffected sides for forearm supination and elbow flexion. The strength testing will be done at the Duke sports medicine clinic on a Cybex machine. The strength testing will be performed by a licensed physical therapist at no cost to the patient. The physical therapist will be blinded to the group the subject is assigned.

Patients with biceps tendonopathy that has failed conservative management will undergo a diagnostic shoulder arthroscopy with a tenotomy or tenodesis of the long head of the biceps tendon if indicated. Either treatment is considered to be standard of care for biceps tendonopathy. Patients will return for routine follow up visits two weeks, six weeks, three months, and four to six months after surgery. At each visit patients will undergo a history and physical exam. Patients will also begin physical therapy following biceps tenodesis several weeks after surgery to begin working on range of motion and strengthening of the upper extremity. In general, patients do not require and are not referred for physical therapy after a biceps tenotomy, but may initiate physical therapy if other conditions such as supraspinatous tendonopathy or a rotator cuff tear, for example, exist.

Current Status:

Subject Recruitment currently underway.

Gait Analysis for Various Surgical Approaches Prior to and Following Total Hip Arthroplasty

The aim of this study is to determine if the type of surgical approach alters lower extremity function during walking gait, as well as potentially improves gait mechanics 6 months and 1 year after a total hip arthroplasty. In addition to monitoring post-operative gait parameters, this study will examine various patient specific factors, such as perception of pain, hip range of motion (ROM), self-reported physical function and post operative complications to determine if any of these variables significantly influence post-operative gait and strength parameters.

Subjects will be identified through the use of a database that tracks patients who have received joint replacements at Duke University. Patients who have received a total hip arthroplasty will be tested at approximately 6weeks, 6 months (5-7 months), and 1 year (10 months – 14 months). Patients who have had a total hip arthroplasty approximately six weeks ago will be identified from the surgical database or patients will be enrolled when they are scheduled for total hip arthroplasty by the treating physician. An equal number of patients who had the anterior, direct lateral or the posterior surgical approach for their operation will be included in the study. Each subject who is identified will have his/her chart reviewed for clinical data. The charts will be reviewed from the patient’s pre-operative visits through his/her post-operative recovery and will include any imaging that is available in his/her record. Specifically patient’s age, weight, height, sex, previous medical and surgical history involving either lower extremity, comorbidities, concomitant joint involvement, findings from the neurovascular examination of the lower extremities, physical exam findings, Harris Hip Score and UCLA score will be recorded. Patients will then be contacted via phone or mail and will be asked if they are willing to return to the Michael W. Krzyzewski Human Performance Lab (K-Lab) for gait analysis and strength testing. Based on the patients who are willing to return, we will try and match, by age, gender, height, and weight the subjects in the three test groups. We are going to recruit a total of 45 subjects (15 from each approach). In addition, a group of 15 normal healthy controls that are matched, by age, height, weight, and gender will be tested one time in order for comparison.

Subjects will range in age from 40-60 years old and will be recruited based on the chart search from the operative database. Subjects will be excluded if they have a history of previous lower extremity fractures or surgeries, other joint involvement with degenerative changes, any chronic lower extremity abnormalities severely compromising gait, history of other joint replacements in the lower extremities, previous history of peripheral neuropathy, CVAs, or peripheral vascular disease. Subjects who participate in this study will be required to walk along a 40 meter walkway approximately 10 times; therefore, subjects need to be able to ambulate well without the use of assistive devices. Each subject will be asked to read and sign the consent form approved by the institutional review board at the university. Testing should take approximately one hour on a single day, subjects will not be asked to return for any further testing.

After signing the consent form, height, weight, foot length, and foot width at the metatarsal heads will be recorded. Subjects will then be asked to complete a series of clinical tests.

The subjects will be asked to complete a sit-to-stand test, which will assess their ability to stand up from sitting and then return to sitting over a 60 second period. Next subjects will be asked to complete a timed get-up and go test. During this test, they will be asked to start in a chair in a seated position, when asked to start, they will get up from the chair, go around an object that is positioned 8 feet away and then return to the chair. The subject will be timed from the start command until he/she returns to the chair. Each subject will be allowed to practice one time and then the time will be recorded for 3 subsequent tests. Following the clinical assessment, patients will begin the gait analysis portion of the study.

A total of eight infrared cameras (Motion Analysis, Inc, Santa Rosa, CA) will be positioned around the walkway in order to record the trajectories of the retro-reflective markers at a sampling rate of 60 Hz, which will be placed on the subjects. A total of 25 markers will be placed on each subject at the following anatomic landmarks: joint space between the fourth and fifth lumbar vertebrae (L4-L5), bilateral acromioclavicular joint, lateral epicondyle of the wrist, the midpoint between the radial and ulnar styloids, anterior superior iliac spine (ASIS), anterior thigh, lateral femoral condyle, anterior lower leg over the tibial ridge, lateral malleolus, heel, and toe, at the second webspace. In addition, markers will be placed bilaterally on the medial femoral condyle and the medial malleolus. Following the placement of all of the markers, subjects will be asked to stand within the view of the cameras facing the direction they will be moving and a static standing trial will be recorded. Following the collection of the static standing trail, the four medial markers will be removed and the subject will be ready for his/her walking trial. The walkway is approximately 40 meters in length and is approximately 6 feet wide. Subjects will be asked to walk along the walkway across a set of 4 force plates (AMTI, Watertown, MA), which can be positioned to record bilateral foot strike. The force plates will be sampling at 1200Hz in order to record the vertical, medial/lateral, and anterior/posterior ground reaction forces as well as the moments in all three planes of movement. Participants will be asked to walk at a comfortable speed for them, their normal walking speed, as they are timed using two sets of infrared timers for a total of 7 good trials. Good trials will be defined as trials in which all of the markers can be identified as well as having a good force plate contact under both feet. Subjects will then be asked to complete 7 trials at a fast speed (walking as fast as they can), while speed as well as kinetics and kinematics are recorded. Subjects will be allowed to rest as much as needed during the walking trials. In addition, patients will be asked to perform a lateral stepping task that will involve stepping onto an object that is 12 inches high. Subjects will be asked to start next to the object and on command, they will be asked to step laterally, without rotating their hips. Both step up time and the lower extremity kinematics will be recorded. Subjects will be given 1 practice trial per task in order to become comfortable with each task. They will then complete 7 trials for each task data collection. An acceptable trial will be one in which the kinematic data are collected successfully and the subject correctly contacts the force place.

Current Status:

Subject recruitment has started for this study.