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ABSTRACT: Adipose tissue-derived stem cells and insulin-like growth factor-1 (IGF-1) have shown potential to enhance peripheral nerve regeneration. The purpose of this study was to investigate the effect of an in vivo biologic scaffold, consisting of white adipose tissue flap (WATF) and/or IGF-1 on nerve regeneration in a crush injury model. Forty rats all underwent a sciatic nerve crush injury and then received: a pedicled WATF, a controlled local release of IGF-1, both treatments, or no treatment at the injury site. Outcomes were the normalized maximum isometric tetanic force (ITF) of the tibialis anterior muscle and histomorphometric measurements. At 4 weeks, groups with WATF had a statistically significant improvement in maximum ITF recovery, as compared to those without (P < 0.05), and there was an increase in myelin thickness and total axon count in the WATF-only group versus control (P < 0.01). Functional and histomorphometric data suggest that IGF-1 suppressed the effect of the WATF. Use of a pedicled WATF improved the functional and histomorphometrical results after axonotmesis in a rat model. IGF-1 does not appear to enhance nerve regeneration in this model. Utilizing the WATF may have a beneficial therapeutic role in peripheral nerve injuries.
Microsurgery 05/2013; · 1.61 Impact Factor
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Peter Tang
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ABSTRACT: The ulnar and radial collateral ligaments are primary stabilizers of the thumb metacarpophalangeal (MP) joint. Injury to these ligaments can lead to instability and disability. Stress testing is essential to establish the diagnosis. Complete tear is diagnosed on physical examination when the proximal phalanx of the thumb can be angulated ulnarly or radially on the metacarpal head by 30° to 35° with the MP joint in either zero degrees of extension or 30° of flexion. Lack of a firm end point or angulation measuring >15° on stress testing compared with the contralateral thumb MP joint are also indicative of complete tear. Partial ligament injuries may be managed nonsurgically, but complete tears are usually managed surgically. Various techniques are used to reattach the ligament to bone, including suture anchors and, less commonly, repair of midsubstance tears. Options for managing chronic injuries include ligament repair, ligament reconstruction with a free tendon graft, and arthrodesis of the MP joint.
The Journal of the American Academy of Orthopaedic Surgeons 05/2011; 19(5):287-96. · 2.66 Impact Factor
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ABSTRACT: The 10 mm rat sciatic nerve defect model is commonly used to investigate new strategies to improve functional recovery with segmental nerve defects. However, a lack of standardization makes comparisons between studies difficult. The present study aims to evaluate a standardized experimental model that can minimize the number of animals required for obtaining valid results and simulates a current treatment for human peripheral nerve injury defects. Eighteen cadaveric Sprague-Dawley rats were utilized in the anatomic arm of the study and 18 living Sprague-Dawley rats were used in the experimental arm. The results from the cadaveric study allowed us to create an ipsilateral, three-cable autologous sural nerve graft technique in the rat. This repair construct was evaluated with functional and histomorphometric analysis of nerve regeneration. The results support functional recovery of the sciatic nerve in all grafted animals. The use of an ipsilateral cabled sural nerve graft technique in the rat sciatic nerve defect model is a viable control group that utilizes a single incision, incurs minimal morbidity, and maintains muscle attachments. We conclude that this rat model can be used in various experimental trials in the field of peripheral nerve regeneration.
Journal of neuroscience methods 02/2011; 197(1):137-42. · 2.30 Impact Factor
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ABSTRACT: Extensor tendon injuries are widely believed to be straightforward problems that are relatively simple to manage. However, these injuries can be complex and demand a thorough understanding of anatomy to achieve the best functional outcomes. When lacerations occur in the forearm as in Zones VIII and IX injury, the repair of the extensor tendon and muscle, and posterior interosseous nerve (PIN) is often challenging. A review of the literature shows little guidance and attention for these injuries. We present four patients with injuries to Zones VIII and IX as well as a review of surgical technique, postoperative rehabilitation, and pearls that may be of benefit to those managing these injuries.
Advances in orthopedics. 01/2011; 2011:261681.
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ABSTRACT: Achieving union to prevent scaphoid nonunion advanced collapse wrist in the scaphoid nonunion is a challenging clinical problem. Much of the difficulty relates to the tenuous blood supply to the scaphoid. One unsolved reconstructive problem is the collapsed scaphoid that requires an intercalated wedge graft with proximal pole avascular necrosis. We offer a simple technique that only requires preservation of the superficial palmar branch of the radial artery that is typically ligated during the volar approach to the scaphoid. This technique can also be used during any open volar approach to the scaphoid to increase vascularity and healing.
Techniques in hand & upper extremity surgery 09/2010; 14(3):160-72.
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ABSTRACT: Individual fracture patterns demand specific and adequate fixation. Locked volar plating has become popular in the operative fixation of distal radius fractures. However, in cases in which there is a radial styloid fragment or in cases of severe comminution, the amount of fixation from volar plating alone can be inadequate and may lead to loss of reduction. The use of locked radial column plates or Kirschner (K) wires provides additional radial column fixation and allows the surgeon to tailor the amount of fixation to the individual fracture pattern. Outlined here is the technique of combining volar plating with locked radial column plating or K-wire fixation, as well as a step-by-step outline to help achieve fracture reduction.
Techniques in hand & upper extremity surgery 09/2010; 14(3):143-9.
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ABSTRACT: Soft tissue fixation of ligaments and tendons in the hand can be achieved by the use of metal or bioabsorbable suture anchors. Advantages of bioabsorbable suture anchors include lack of interference in magnetic resonance imaging, resorption of anchor, replacement by bone, and no need for hardware removal. However, complications of these bioabsorbable implants include inflammatory response to the material use. We present what we believe to be the first case in the hand of a poly(l-lactide-co-d,l-lacitide) suture anchor causing an inflammatory response leading to significant osteolysis 4 months postoperatively after repair of a ring finger flexor digitorum profundus avulsion. Exploration of the distal phalanx revealed an intact implant and repair, no signs of infection, and an extensive bone defect. Pathology showed chronically inflamed tissue. This case has led us to reconsider the use of bioabsorbable anchor sutures in the hand. Further research is necessary to better define the contraindications to bioabsorbable suture anchor use in the hand.
Hand 11/2009; 5(3):307-12.
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ABSTRACT: The proximal row carpectomy (PRC) is a clinically useful motion-preserving procedure for various arthritides of the wrist. However, there are few studies on the "contact biomechanics" after PRC. The purpose of this study is to evaluate the contact biomechanics in terms of pressure, area, and contact location of the intact and PRC wrist.
Six fresh-frozen cadaver forearms were tested in neutral, 45 degrees of flexion, and 45 degrees of extension. In the intact wrist, Fuji UltraSuperLow pressure contact film was placed in the radioulnocarpal joint. The specimen was loaded to a total force of 200 N. We then performed a PRC, and the experiment was repeated using Fuji Low film. The film was scanned and analyzed with a customized MATLAB program. Multivariable analysis of variance with multiple contrast testing and Student's t-test were performed for statistics.
In the intact wrist, scaphoid contact pressure averaged 1.4 megapascals (MPa), and lunate contact pressure averaged 1.3 MPa. In terms of contact location, scaphoid contact in the intact wrist significantly moved dorsal and ulnar in flexion and significantly moved volar and radial in extension. Lunate contact significantly moved dorsal in flexion. PRC wrist contact pressure was 3.8 times that of the intact wrist, and the contact area was approximately 26% that of the intact wrist. Lastly, in terms of the amount of contact translation after PRC, the capitate contact translated (7.5 mm) more than did the scaphoid contact (5.6 mm) and had about equal translation to that of the lunate (7.3 mm).
Contact pressure increased significantly and contact area decreased significantly after PRC. There is significant contact translation after PRC (more than scaphoid translation but equal to lunate translation), which provides quantitative support of the theory that translational motion of the PRC may explain its good clinical outcomes.
The Journal of hand surgery 05/2009; 34(4):660-70. · 1.33 Impact Factor
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ABSTRACT: Proximal row carpectomy (PRC) can be an effective treatment option for arthritis of the wrist, but the operation is contraindicated when there is substantial arthritis of the capitate head. We describe a new technique that involves resurfacing of the capitate when there is chondrosis by using osteochondral grafts harvested from the resected carpal bones. The purpose of this study was to assess the outcomes of patients who had osteochondral resurfacing in the setting of PRC (OCRPRC) for capitate chondrosis and to determine how they compare with published results of conventional PRC.
Patients having PRC who had grade II to IV (Modified Outerbridge Scale) capitate chondrosis underwent osteochondral resurfacing of the capitate. Preoperative and postoperative pain level, employment status, range of motion (ROM), grip strength, and Mayo wrist scores were assessed, and Student's t-test was used. Postoperative Disability of the Arm, Shoulder and Hand (DASH) scores were also calculated.
Eight patients with an average age of 53 years were followed up for 18 months. Preoperatively, 7 patients described their pain as moderate to severe; postoperatively, 7 patients described their pain as mild to no pain. Preoperative arc of motion was 84 degrees (74% of the contralateral side); postoperative arc of motion was 75 degrees (66% of the contralateral side). Preoperative grip strength was 29 kg, or 62% of the contralateral side; postoperative grip strength was 34 kg, or 71% of the contralateral side. Preoperative Mayo wrist score was 51 ("poor"); postoperative Mayo wrist score was 68 ("fair"). Average postoperative DASH score was 19.5. Follow-up radiographs showed that 75% of patients had mild to no degeneration. Magnetic resonance imaging at 21 months postoperatively showed graft incorporation. No complications were encountered.
Our results with osteochondral resurfacing compare favorably with the published results of conventional PRC in terms of pain relief, employment status, ROM, and grip strength.
The Journal Of Hand Surgery 12/2007; 32(9):1334-42. · 1.35 Impact Factor
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ABSTRACT: Proximal row carpectomy (PRC) is a clinically useful motion-sparing procedure for the treatment of certain degenerative conditions of the wrist. Clinical outcome studies after PRC have shown that wrist flexion-extension averages approximately 60% of that of the contralateral wrist. The purpose of this study was to determine how the kinematics of the wrist are altered after PRC.
Eight fresh-frozen cadaver forearms were scanned with computed tomography before and after PRC. Forearms were scanned in 5 different wrist positions (neutral, extension, flexion, radial deviations, and ulnar deviation). Wrists were positioned dynamically and then held statically in a custom fixture through forces applied to the 4 wrist flexor/extensor tendon groups. Three-dimensional computer models of the radius, lunate, and capitate were generated from the computed tomographic images, and the kinematics of the capitate and lunate were calculated relative to the neutral position. For the intact wrist, the motion of the capitate was calculated relative to both the lunate (midcarpal motion) and the radius (overall wrist motion) and the motion of the lunate was calculated relative to the radius (radiocarpal motion). After PRC, only the movement of the capitate relative to the radius was calculated, which represents radiocapitate and overall wrist motion. All motions were plotted in 3 dimensions for purposes of qualitative visualization.
After PRC, the capitate articulated with the lunate fossa of the radius for all positions in all samples. Overall wrist motion decreased 28%, 30%, 40%, and 12% in flexion, extension, radial deviation, and ulnar deviation, respectively. Motion at the radiocarpal joint after PRC, however, was greater compared with motion at the radiocarpal and midcarpal joints of the intact wrist during flexion and extension. This was not the case in radial deviation because of impingement of the trapezoid on the radial styloid. In radial and ulnar deviation, motion of the capitate head changed from predominantly rotational in the intact wrist (midcarpal joint) to a combination of rotation and translation after PRC (radiocarpal joint).
Removal of the proximal carpal row decreased normal wrist flexion and extension. Although ulnar deviation was preserved, radial deviation was limited by impingement of the trapezoid on the radial styloid. Radiocapitate range of motion after PRC was greater than capitolunate range of motion in the intact wrists. Compared with previously published requirements, wrist range of motion observed after PRC was sufficient for activities of daily living.
The Journal Of Hand Surgery 02/2007; 32(1):37-46. · 1.35 Impact Factor
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ABSTRACT: To evaluate whether an open technique used to obtain reduction during intramedullary nailing of closed tibial shaft fractures increases the risk of infection, compared to closed reduction and nailing.
University level 1 trauma center.
Retrospective database analysis.
One hundred seventeen patients with 119 fractures from our trauma database who had sufficient follow-up and met study criteria. The patients were grouped by open versus closed reduction. Only OTA fracture types 42 A to C were included in this study.
Locked reamed intramedullary nailing for closed tibial shaft fractures accomplished through either open or closed reduction.
The presence or absence of infection as determined by the clinical presentation (erythema, warmth, purulent drainage, fevers, chills, increased pain at the fracture site), indicative laboratory work (complete blood count, erythrocyte sedimentation rate, C-reactive protein), and/or positive culture.
There were 85 males and 32 females. The average age was 35.7 years; the average follow-up was 14.3 months. Of the 119 fractures, 79 had closed reduction whereas 40 had open reduction. The open reductions consisted of 13 with a formal incision (>1 cm in length), 22 with percutaneous incisions, and 5 with fasciotomies. There were no infections in the closed reduction group and 2 infections (5%) in the open reduction group. This difference was not statistically significant (P=0.1). The average time to union was 7.0 months in closed reductions and 7.3 months in open reductions. By latest follow-up, 107 fractures had reached union (89.9%), 1 had not (0.8%), and 11 were lost to final follow-up (9.2%).
Limited open techniques can greatly facilitate the reduction of closed tibial shaft fractures but raise concern for infection through exposure of the fracture site. This study found that the rate of infection for open versus closed reductions was higher but not statistically different. Judicious use of open reduction techniques during intramedullary nailing of closed tibia fractures seems to have a minimal risk of infection.
Journal of Orthopaedic Trauma 05/2006; 20(5):317-22. · 2.13 Impact Factor
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ABSTRACT: The loads needed to elicit a positive pivot shift test in a knee with an anterior cruciate ligament (ACL) rupture have not been quantified. The coupled anterior tibial translation (ATT), coupled internal tibial rotation (ITR), and the in situ force in the ACL in response to a valgus torque, an inherent component of the pivot shift test, were measured in 10 human cadaveric knee specimens. Using a robotic/universal force-moment sensor testing system, valgus torques ranging from 0.0 to 10.0 Nm were applied in nine increments on the intact and ACL-deficient knee in flexion ranging from 0 degrees to 90 degrees. At 15 degrees of knee flexion, the coupled ATT and ITR were significantly increased in the ACL-deficient knee when compared to the intact knee. Coupled ATT increased a maximum of 291% (6.7 mm, p<0.05), while coupled ITR increased a maximum of 85% (5.1 degrees, p<0.05). At 30 degrees, the increases in coupled ATT and ITR were significant at valgus loads of 3.3 Nm and greater with a maximum increase in coupled ATT of 137% (6.3 mm, p<0.05) and a maximum increase in coupled ITR of 38% (3.6 degrees, p<0.05). At 45 degrees, coupled ATT increased significantly (maximum of 69%, 4.4 mm, p<0.05), but only at torques > or =6.7 Nm. The in situ force in the ACL was less than 20 N for all flexion angles when a torque between 3.3 and 5.0 Nm was applied. Low valgus torque elicited tibial subluxation in the ACL-deficient knee with low in situ ACL forces, similar to a positive pivot shift test. Thus, application of a valgus torque may be suitable to evaluate ACL-deficient and ACL-reconstructed knees, since subluxation can be achieved with minimal harm to the ACL graft. This work is important in understanding one load component needed for the pivot shift examination; further studies quantifying other load components are essential for better comprehension of the in vivo pivot shift examination.
Journal of Orthopaedic Research 11/2003; 21(6):1107-12. · 2.81 Impact Factor
