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ABSTRACT: Abstract Purpose: Anatomic double-bundle ACL reconstruction presents a unique technical challenge for surgeons, requiring precise placement of multiple tunnels in a relatively small area. As the necessity of anatomic reconstruction has been stressed throughout the literature, developing a method to consistently improve the accuracy and precision of tunnel placement is essential. We aimed to investigate whether computer-assisted navigation allows novice surgeons to place double-bundle ACL tunnels with a similar degree of accuracy to experienced surgeons operating without computer assistance. Methods: A novice surgeon group comprising three medical students performed double-bundle ACL reconstruction using passive computer-assisted navigation in 11 cadaver knees. Their individual results were compared to those of three experienced orthopaedic surgeons, each performing the identical procedure without the use of computer-assisted navigation in 9 cadaver knees. Results and conclusion: There were no significant differences in placement of either the AM or PL tunnels on the tibial plateau between the novice surgeons using computer-assisted navigation and the experienced surgeons. However, on the lateral femoral condyle, the novice surgeons placed the AM and PL tunnels significantly more anterior along Blumensaat's line, on average, compared to the experienced surgeons.
Computer Aided Surgery 05/2013; · 0.30 Impact Factor
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ABSTRACT: Patellofemoral joint kinematics are dependent on a variety of anatomical features. One of the most common causes of patellar instability is malalignment of the quadriceps extensor mechanism. The Southwick-Fulkerson osteotomy focuses on correcting malalignment of the quadriceps extensor mechanism through medialization of the tibial tubercle. MRI, in conjunction with established patellofemoral indices, allows quantitative evaluation of the patellofemoral joint during active quadriceps extension both pre- and postoperatively.
This study aims to quantitatively evaluate the effects of extensor mechanism medialization procedures using established patellofemoral indices in order to establish a relationship between tubercle transfer distance and patellar tracking. It is believed that a 15mm medial transfer of the tibial tubercle will produce statistically significant changes in patellar tracking when evaluated during active quadriceps contraction.
Four fresh-frozen cadavers underwent a modified Fulkerson osteotomy. The central quadriceps tendon was identified and traction was applied with a vector parallel to the femoral diaphysis using sutures, to simulate active quadriceps contraction. MRI images were obtained following Omm (control) and 15mm tibial tubercle medialization. Each knee was evaluated at 30, 20, 10, and 0 degrees of flexion. Results: Quantitative evaluation of patellar tracking during active quadriceps contraction detected significant changes in patellar translation following 15mm medial transfer of the tibial tubercle as compared to the control. The significantly reduced indices suggest reduced patellar lateralization and improved patellar tracking during the critical range of motion from 30 to 0 degrees of flexion.
The results of this study indicate that significant quantitative changes in patellar tracking occur following 15mm tibial tubercle medialization when evaluated during active quadriceps contraction using MRI in conjunction with established patellofemoral indices. These findings suggest that quantitative evaluation of patellar tracking may be a valuable pre- and postoperative tool when coupled with qualitative clinical findings.
The Iowa orthopaedic journal 01/2011; 31:90-8.
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ABSTRACT: The evaluation of distal transfer procedures relies primarily on qualitative clinical findings. Although quantitative MRI measurements provide an objective supplement to qualitative clinical findings, an association between qualitative clinical findings and quantitative patellofemoral indices has yet to be established.
A 21-year-old man presented with frequent episodes of patellar dislocation. Clinical and radiographic findings identified the patient as a candidate for realignment. MR images were obtained with the quadriceps contracted at 30° flexion and in full extension preoperatively and postoperatively. The procedure eliminated the clinical J-sign, defined as lateral movement of the patella over the lateral femoral condyle during active leg extension, which was confirmed quantitatively using established patellofemoral indices in conjunction with MRI.
Movement of the patellofemoral joint is complex and dependent on many factors, including skeletal geometry, dynamic muscle action, and soft tissue restraints. Therefore, proper clinical and radiographic evaluation of patellar tracking requires observation during active quadriceps contraction. However, it is unclear whether there is any association between quantitative radiographic indices and qualitative clinical assessment during active quadriceps contraction.
We believe objective measurements are valuable in determining the radiographic assessment of patellar realignment procedures. Lateral patellar edge appears to quantify the clinical J-sign. The association between radiographic medialization of the patella and clinical improvement postoperatively in this patient warrants additional investigation in a larger group of patients with longer followup.
Clinical Orthopaedics and Related Research 10/2010; 469(1):294-9. · 2.53 Impact Factor
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ABSTRACT: Dynamic intraoperative assessment of patella tracking utilizes femoral nerve stimulation to contract the quadriceps muscles in assessing the proper distance to transfer the tibial tubercle during distal realignment procedures for patellofemoral instability.
We describe the effects of tourniquet inflation and catheter placement on intraoperative femoral nerve stimulation for assessment of patellar tracking.
Percutaneous electromyographic (EMG) needles were placed into the quadriceps and sartorius muscles to monitor muscle activity and changes in amplitude threshold (mA) required for femoral nerve stimulation with increasing tourniquet inflation times. Eleven patients used ultrasound for catheter placement and ten were manually placed based upon body landmarks.
Tourniquet application time correlated positively with the change in amplitude threshold required to generate muscle contraction. Patients had an average four-fold increase in required stimulus amplitude from the baseline thresholds (pre-tourniquet inflation) to final thresholds (tourniquet inflated) with a two-hour tourniquet inflation time. The use of ultrasound for catheter placement significantly decreased the baseline amplitude required in comparison with catheters placed without ultrasound, (p = 0.0330).
Increased tourniquet inflation times require greater stimulus amplitude to generate quadriceps muscle contraction. Ultrasound guidance for catheter placement can provide femoral nerve stimulation at low amplitudes.
The Iowa orthopaedic journal 01/2010; 30:104-8.
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ABSTRACT: Currently, a significant proportion of effort on cartilage tissue research is devoted to establishing the most effective method of inducing cartilage repair. However, the studies themselves lack uniform documentation and comparisons are difficult to make. If valuable therapeutic information is to be gained from future studies, it is important that an accurate system exists for assessing focal cartilage defects to allow comparison between studies and/or investigators.
Sports medicine and arthroscopy review 07/2008; 16(2):97-102. · 1.16 Impact Factor
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ABSTRACT: Medial transfer of the tibial tubercle is commonly implemented to correct patellar alignment in patients with patellar instability. However, the extent of transfer needed is difficult to determine. This article reports a pilot-study experience with a novel technique employing intraoperative femoral nerve stimulation to better determine the distance of tubercle transfer required for proper patellar tracking. This pilot study is a case series involving seven knees, all with a clinical history of dislocation, evidence of maltracking, and excessive medial patellofemoral ligament (MPFL) laxity to the point of producing a positive apprehension sign. All seven knees received femoral nerve stimulation for patellar tracking assessment as part of a modified Fulkerson osteotomy. All knees received clinical follow-up for a minimum of 24 months. Six of the seven cases in this series remained stable during two years of follow-up. Through these findings we conclude that the use of femoral nerve stimulation for patellar tracking assessment may be associated with a sufficiently high rate of success to warrant more extensive investigation.
The Iowa orthopaedic journal 02/2007; 27:61-4.
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ABSTRACT: Surrogate knee model biomechanical studies have indicated that off-the-shelf braces provide 20% to 30% greater resistance to a lateral blow when the knee is in full extension. Custom functional braces doubled the protective effects and proved effective with the knee in some flexion. Although functional performance studies are not consistent, preventive knee braces may slow straight-ahead sprint speed, cause early fatigue, and increase muscular relaxation pressures, energy expenditure, blood lactate levels, maximal torque output, oxygen consumption, and heart rate. Two epidemiologic studies have been performed. At West Point, a randomized control study of 71 injuries in 1396 cadets indicated knee brace effectiveness with a statistically higher rate of injury in the control group (3.4/1000 exposures) than in the braced group (1.5/1000 exposures), with the most significance for medial collateral ligament sprains in defensive players. The Big Ten Conference conducted a descriptive study of 100 medial collateral ligament sprains among 987 players in different positions, strings, and types of session. Brace-wear tendency varied directly with the unbraced player counterpart's risk of medial collateral ligament sprain, with the nonplayer linemen experiencing both the greatest risk of unbraced practice session injury (0.0801 injuries/1000 exposures) and the highest incidence of brace wear (85%). During practices, there was a nonsignificant but very consistent reduction in injury rate for braced players in every position and string. During games, there was also a reduced rate for linemen and the linebacker/tight end group. The study concluded that although the issue is not closed, preventive knee braces appear to offer some protection to the medial collateral ligament from a contact injury involving a valgus blow, but there may be negative effects on performance level, leg cramping, and fatigue symptoms.
The American Journal of Sports Medicine 05/2005; 33(4):602-11. · 3.79 Impact Factor
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ABSTRACT: We describe a method of dynamic assessment of patellar tracking intraoperatively during a Fulkerson osteotomy. We utilize an electrically conductive catheter intraopertively to directly stimulate the femoral nerve to cause quadriceps muscle contraction. The resultant active knee extension allows dynamic assessment of patellofemoral tracking prior to and after final Fulkerson fixation. This dynamic intraopertive technique allows us to approximate in vivo patellofemoral motion better than with passive motion assessment.
The Iowa orthopaedic journal 02/2005; 25:160-3.
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John P Albright,
John W Powell,
Al Martindale,
Robert Black,
Edward Crowley,
Paul Schmidt,
Jeff Monroe,
Doug Locy,
Tory Aggler,
W R Davis, [......],
Stephen Soboroff,
Jim Nivens,
James Carpenter,
Jeff Kovan,
Elizabeth Arndt,
Howard Sweeney,
John Lombardo,
Wayne J Sebastianelli,
Michael Krauss,
Greg Landry
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ABSTRACT: In 1998, the National Collegiate Athletic Association legislated a decrease in the number of scrimmages and full-contact practices allowed during the spring season.
A significantly increased risk of injury faced by the same player during the spring versus fall practice sessions does exist, but the National Collegiate Athletic Association regulations will not have the intended effect of reducing injury rates to equal or below those of the fall practice sessions.
Retrospectively analyzed, descriptive study of prospectively collected injury surveillance data followed by a prospective, controlled, repeated-measures study after the rule change.
Phase 1: the Big Ten Conference Sports Injury Surveillance System database was reviewed from spring 1992 through fall 1997 for all reportable injuries. Phase 2: a prospective investigation was instituted from spring 1998 through fall 2000. This protocol was modified to also document updated individual player position descriptions and string as well as exposures for the old fall and spring practice categories (scrimmages, full contact, and limited contact) and the new spring practice designations (full pads with and without tackling, helmets only, spring game, and other scrimmages).
Phase 1: There were 3950 fall injuries and 1007 spring injuries, with 469 of the 1007 attributable to the "spring risk factor." There was a statistically significant increase in injury rate in the spring (19.8) versus fall (10.6). Scrimmages (incidence density ratio = 2.4) and limited-contact practices (incidence density ratio = 2.5) showed more than twice the fall injury rate. Phase 2: There were 1502 fall injuries and 648 spring injuries, with 192 attributable to the spring risk factor. There was a 3-fold increase in injury rate in the spring (incidence density ratio = 3.2). Although the noncontact, helmets-only practices produced the lowest injury rates, the nonspring game scrimmages and the limited-contact practices defined as "practice with pads but without tackling" displayed the highest injury rates. In both spring and fall, nonplayers exhibited the highest injury rates for all string groups.
There was and still is a statistically significant increase in spring practice injury risk. The 1998 rule change resulted in an even greater increase in spring practice injury risk. If the goal is to minimize the number of spring practice injuries, it will be best accomplished by limiting the number of scrimmages and limited-contact sessions.
The American Journal of Sports Medicine 10/2004; 32(6):1394-404. · 3.79 Impact Factor
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ABSTRACT: Capsular attenuation has been seen after thermal capsulorrhaphy surgery. The purpose of this study was to evaluate the mechanical, histologic, and morphologic effects on capsular tissue after cumulative applications of radiofrequency energy. Ovine patellofemoral capsular tissue was treated with 1, 2, 4, or 8 applications of bipolar radiofrequency energy and then analyzed. No acute capsular ablation or destruction was seen grossly, even in the 8-application group. No definitive visual clues that excessive radiofrequency energy had been applied were seen. There was significant shrinkage and loss of tensile stiffness for all thermal application groups. Given the small sample sizes, post-application failure load, percent relaxation, and stiffness were not observed to be significantly different among the groups. Cumulative applications produced minimal further tissue shrinkage but were accompanied by larger, though not statistically significant, mechanical property losses and increased depth of tissue penetration. These findings suggest that there is no benefit to repeated applications of radiofrequency energy to capsular tissue.
Journal of Shoulder and Elbow Surgery 14(2):149-56. · 2.75 Impact Factor
