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Biomedical subjects

M J Hulstyn

Publications and source records attributed to M J Hulstyn.

16 recordsLinked to original sources
PubMed2001

Meniscal tissue regeneration using a collagenous biomaterial derived from porcine small intestine submucosa.

PURPOSE: The present investigation is a preliminary study designed to evaluate the use of a collagen-based biomaterial, chemically unaltered porcine small intestine submucosa (SIS), as a scaffold for meniscal tissue regeneration. TYPE OF STUDY: Basic research. METHODS: Surgical defects were created in the lateral menisci of 12 mature New Zealand white rabbits. The defects were repaired with a similarly shaped and sized wedge of a new collagenous biomaterial (SIS) and sutured in place. The opposite knees served as controls by creating a defect in the lateral meniscus without filling with SIS graft. Full cage activity was allowed until the animals were killed at 4, 12, and 24 weeks. RESULTS: At 4 weeks, the graft material retained its physical position and grossly appeared soft and translucent. Histologically, cellular elements had infiltrated between the laminates of the graft. At 12 weeks, the graft grossly appeared more solid and opaque. Histologically, the host meniscal fibrochondrocytes were seen streaming into the peripheral margin of the graft. Early repopulation of the graft with apparently differentiated meniscal tissue was observed. At 24 weeks, the meniscus defect was grossly healed across and looked virtually normal: the normal meniscal shape, contour, consistency, and color had been replicated. Histologically, the healing tissue showed infiltration of what appeared to be meniscal fibrochondrocytes and connective tissue resembling the host meniscal tissue. The graft was nearly totally replaced by host tissue. CONCLUSIONS: This pilot animal study demonstrates that the multilaminated collagenous graft is conducive for cellular repopulation with host meniscal elements, and, by 24 weeks, is capable of supporting complete healing of a large meniscal defect.

Animals↗
PubMed2000

The effect of tubularization on the mechanical properties of patellar tendon grafts.

To determine the effect of tubularization on the prefailure mechanical properties of bone-patellar tendon-bone autografts used for anterior cruciate ligament repair, 10 bovine bone-patellar tendon-bone grafts were tested in tension before and after tubularization with running suture. The testing protocol involved a 5-N preload, 10 preconditioning cycles to 200 N, and a final test cycle to 950 N at 1000 N/sec. Five of the grafts were tested first as harvested (flat) and then again following tubularization. The remaining five grafts were tubularized prior to the initial testing, and final testing was done with the suture removed. Raw testing data were reduced to determine the amount of stretching associated with preconditioning, as well as laxity and stiffness of the preconditioned grafts. Tubularized grafts stretched significantly more than flat grafts during preconditioning: 3.5 times as much after the first preconditioning cycle (3.8+/-1.9 mm versus 1.1+/-0.78 mm) and 3.1 times as much after 10 cycles (5.0+/-2.1 mm versus 1.6+/-0.9 mm). There was no statistically significant difference in the stiffnesses of the tubularized and flat grafts, nor did tubularization have an effect on graft laxity. Interestingly, there was a slight increase in laxity the second time each graft was tested, regardless of whether the graft was flat or tubularized when it was first tested. These results highlight the importance of preconditioning patellar tendon grafts before fixation, especially those that have been tubularized.

Animals↗
PubMed1998

Emergency removal of football equipment: a cadaveric cervical spine injury model.

STUDY OBJECTIVE: To determine the influence of football helmet and shoulder pads, alone or in combination, on alignment of the unstable cervical spine. METHODS: The alignment of the intact cervical spine in 8 cadavers was assessed radiographically under 4 different football equipment conditions: (1) no equipment, (2) helmet only, (3) helmet and shoulder pads, and (4) shoulder pads only. Each specimen was then surgically destabilized at C5-C6 to simulate a flexion-distraction injury. Repeat radiographs were obtained under the same 4 equipment conditions, and alignment of the unstable segment was analyzed. RESULTS: Before the destabilization, neutral alignment was maintained when both helmet and shoulder pads were in place. The "helmet only" condition caused a significant decrease in lordosis (mean, 9.6 +/- 4.7 degrees), whereas the "shoulder pads only" condition caused increased lordosis (13.6 +/- 6.3 degrees). After destabilization, the "helmet-only" condition demonstrated significant mean increases in C5-C6 forward angulation (16.5 +/- 8.6 degrees), posterior disc space height (3.8 +/- 2.3 mm), and dorsal element distraction (8.3 +/- 5.4 mm). CONCLUSION: Our flexion-distraction model demonstrated that immobilization of the neck-injured football player with only the helmet in place violates the principle of splinting the cervical spine in neutral alignment. By extrapolation to an extension-type injury, immobilization with only the shoulder pads left in place similarly violates this principle. In order to maintain a neutral position and minimize secondary injury to the cervical neural elements, the helmet and shoulder pads should be either both left on or both removed in the emergency setting.

Aged↗
PubMed1998

Initial fixation strength of polylactic acid interference screws in anterior cruciate ligament reconstruction.

The initial fixation properties of bioresorbable polylactic acid (PLA) interference screws designed for anterior cruciate ligament reconstruction were evaluated using an in vitro bovine model. The surgical technique of interference screw fixation of the bone-patellar tendon-bone autograft complex performed clinically was reproduced in an adult bovine model. The reconstructed knee was tested oriented in 30 degrees of flexion to allow examination of the femoral and tibial fixation properties simultaneously. This model examined the initial fixation strength between PLA and metal interference screws as well as a partially degraded PLA implant. Data from this in vitro model indicate that PLA interference screws can provide similar initial fixation at both time 0 and after degradation for up to 28 days compared with metal interference screws for bone-tendon-bone ACL reconstructions.

Absorption↗
PubMed1998

Pediatric throwing injuries about the elbow.

Pediatric elbow injuries that result from repetitive throwing-type activities are common. These injuries differ from those seen in adults, because of anatomic differences. The purpose of this paper is twofold: first, to review the anatomy of the elbow and the mechanics of the throwing motion about the elbow, and second, to discuss the diagnosis, treatment, rehabilitation, and prevention of pediatric throwing injuries of the elbow.

Adolescent↗
PubMed1998

A comparison of MRI findings in patients with acute and chronic ACL tears.

This retrospective study compared the magnetic resonance imaging (MRI) findings in 87 patients with acute and chronic anterior cruciate ligament (ACL) tears. Sixty patients had acute tears and 27 had chronic tears. The appearance of the torn ligament was examined on MRI, and associated meniscal and osteochondral injuries were described. All findings were verified at arthroscopy. Acute ACL tears (MRI examination was performed within 6 weeks of injury) were typified by the presence of diffuse (58%) or focal (42%) increased signal within the ligament, whereas chronic ACL tears (MRI examination was performed more than 6 months after injury) usually appeared as either a fragmented ligament (44%) or an intact band of low signal with abnormal orientation (30%). Patients with chronic ACL tears had a higher prevalence of medial meniscal tears (78% versus 40%), articular chondromalacia, and an increased posterior cruciate bow ratio (0.47 versus 0.37) in association with chronic ACL tears. A bone bruise was seen in 68% of acute ACL tears but in no case of chronic ACL tear. On MRI, there are salient differences between acute and chronic ACL tears. Chronic ACL tears are associated with a greater prevalence of meniscal and osteochondral injuries. These findings may have implications for future treatment recommendations.

Acute Disease↗
PubMed1997

Common athletic knee injuries.

Knee injuries continue to be an increasingly common and highly visible problem presenting to the sports medicine physician. The physicians who handle knee injuries will be challenged by patients, coaches, trainers, business agents, the press, and family members with an ever-increasing sophistication of medical knowledge. An understanding of the underlying structure and function of the commonly injured ligaments, menisci, and the patellofemoral joint is discussed. Diagnosis by physical examination is encouraged. Conservative and surgical treatment options are reviewed as are the considerations involved in deciding the time to return to sports.

Athletic Injuries↗
PubMed1997

Shoulder injuries in the athlete.

Musculoskeletal injuries constantly provide challenges to the team physician, including those to the shoulder. Shoulder injuries are common in athletes, whether as a result of direct contact from a collision or from repetitive overhead motion. This article reviews sports-related injuries to the shoulder, including similarities between sports, clinical evaluation, and rehabilitation of the athletes.

Acromioclavicular Joint↗
PubMed1995

Incidence of deep vein thrombosis after arthroscopic knee surgery: a prospective study.

Deep vein thrombosis (DVT) with subsequent pulmonary emboli (PE) is the most life-threatening complication of knee arthroscopy. Although the incidence of clinically diagnosed DVT after arthroscopy is low, clinical examination is less sensitive and specific than other diagnostic modalities for the detection of venous clot. This study used compression ultrasound to prospectively evaluate patients before and after arthroscopic surgery for the presence of DVT. Preoperatively, patients were screened for DVT risk factors. Eighty-five patients completed the study. Three asymptomatic "silent" DVTs were identified, for an incidence of 3.5%. There was no statistically significant difference between those with and without risk factors for the development of DVT.

Adolescent↗
PubMed1995

Arthroscopic anatomy of the shoulder.

The importance of a thorough knowledge of regional anatomy in any surgical discipline cannot be overemphasized. This is particularly true for the orthopedist as arthroscopic procedures continue to evolve with our increased understanding of shoulder pathology and as we attempt to improve patient outcomes. Surface and bony anatomy allow the arthroscopist to infer the location of the glenohumeral joint and subacromial space. Proper portal placement allows access to these regions without risk of neurovascular, tendon, or articular injury. Glenohumeral and subacromial anatomy can be clearly seen arthroscopically with many normal variants. Knowledge of normal shoulder anatomy allows the orthopedic surgeon to safely and successfully treat pathologic conditions.

Arthroscopy↗
PubMed1993

Adhesive capsulitis of the shoulder.

Adhesive capsulitis of the shoulder is a relatively common problem that can cause significant functional morbidity in a wide variety of patient populations. Numerous treatment methods have been advocated and are reviewed and summarized in this article. Although several advances have been made in determining the etiology of this disorder, it remains poorly understood and without any definitive treatment algorithm.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMedDate not supplied

The effect of protective football equipment on alignment of the injured cervical spine. Radiographic analysis in a cadaveric model.

No universally accepted management protocol is available for dealing with the protective equipment worn by a neck-injured football player. The purpose of this cadaveric study was to determine the effects of the helmet and shoulder pads on the alignment of 1) the intact lower cervical spine and 2) the partially destabilized C5-6 motion segment. In Group I cadavers (N = 15), the lower cervical spine was tested in an intact condition. In Group II (N = 8), the C5-6 motion segment was tested in both an intact and a partially destabilized condition. Each cadaver was placed supine on a backboard and four lateral cervical radiographs were obtained as follows: no protective equipment, helmet only, helmet and shoulder pads, and shoulder pads only. Results for Group I showed that wearing both helmet and shoulder pads did not result in a significant change in cervical lordosis when compared with the neutral position (i.e., the no-equipment test). Cervical lordosis was significantly decreased in the helmet-only category (mean, 9.6 degrees) and significantly increased in the shoulder pads-only category (mean, 13.6 degrees). In Group II, destabilized specimens under the helmet test situation showed a significant mean increase in C5-6 forward angulation (16.5 degrees), posterior disk space height (3.8 mm), and dorsal element distraction (8.3 mm). Immobilizing the neck-injured football player with only the helmet or only the shoulder pads in place violates the principle of splinting the cervical spine in neutral alignment, according to our findings. We support the concept that removal of the helmet and shoulder pads should be an all-or-none proposition.

Aged↗
PubMedDate not supplied

Exercise-induced loss of bone density in athletes.

In athletes, the rarely identified malady of osteoporosis differs from other chronic effects of exercise. The most obvious difference is that hormonal imbalance leads to compensatory mechanisms that in turn lead to osteoporosis and increased incidence of fracture. Most research on this subject has dealt with women, because hormonal imbalances in women are easier to detect than those in men. Endurance athletes are known to have decreased levels of sex hormones, which can cause physiologic changes that lead to bone loss. This may result in relative osteoporosis despite the loading of the bone during exercise, which would normally increase bone mineral density. Premature osteoporosis may be irreversible, causing young athletes to become osteoporotic at an earlier age and have an increased risk of fracture later in life.

Adolescent↗