Video analysis of trunk and knee motion during non-contact anterior cruciate ligament injury in female athletes: lateral trunk and knee abduction motion are combined components of the injury mechanism.

BACKGROUND: The combined positioning of the trunk and knee in the coronal and sagittal planes during non-contact anterior cruciate ligament (ACL) injury has not been previously reported. HYPOTHESIS: During ACL injury female athletes demonstrate greater lateral trunk and knee abduction angles than ACL-injured male athletes and uninjured female athletes. DESIGN: Cross-section control-cohort design. METHODS: Analyses of still captures from 23 coronal (10 female and 7 male ACL-injured players and 6 female controls) or 28 sagittal plane videos performing similar landing and cutting tasks. Significance was set at p < or = 0.05. RESULTS: Lateral trunk and knee abduction angles were higher in female compared to male athletes during ACL injury (p < or = 0.05) and trended toward being greater than female controls (p = 0.16, 0.13, respectively). Female ACL-injured athletes showed less forward trunk lean than female controls (mean (SD) initial contact (IC): 1.6 (9.3) degrees vs 14.0 (7.3) degrees, p < or = 0.01). CONCLUSION: Female athletes landed with greater lateral trunk motion and knee abduction during ACL injury than did male athletes or control females during similar landing and cutting tasks. CLINICAL RELEVANCE: Lateral trunk and knee abduction motion are important components of the ACL injury mechanism in female athletes as observed from video evidence of ACL injury.

Low-risk stress fractures.

Stress fractures can occur in almost any bone in the body, with the lower extremity weightbearing bones, especially the tibia, tarsals, and metatarsals, being affected most frequently. Although the cause of these fractures is multifactoral, repetitive physical forces without adequate rest are the primary culprits. Stress fractures may be broadly classified as low-risk or high-risk injuries. Low-risk stress fractures, the topic of this review article, can be diagnosed through a thorough history, physical examination, and radiographs. Nuclear scintigraphy is occasionally necessary for confirmation, especially for fractures of the spine and pelvis. When diagnosed early and treated with restriction of activity, low-risk stress fractures have a favorable prognosis.

Catastrophic injuries in pole-vaulters.

Pole vaulting is a unique sport in that athletes often land from heights ranging from 10 to 20 feet. We retrospectively reviewed 32 catastrophic pole-vault injuries that were reported to the National Center for Catastrophic Sports Injury Research between 1982 and 1998. The purpose of this study was to determine the mechanisms of injury so that preventive strategies can be implemented. Information was obtained by means of a telephone interview with someone familiar with the accident. All injuries occurred in male athletes at an average age of 17.5 years; 31 were catastrophic head injuries and 1 was a thoracic spine fracture that resulted in paraplegia. Three common mechanisms were identified: 17 (53%) athletes landed with their body on the landing pad and their head on the surrounding hard ground, 8 (25%) landed in the vault box after being stranded at the height of the jump, and 5 (16%) completely missed the landing pad. The mechanism of injury in the remaining two athletes was unknown. The accident resulted in death in 16 (50%) athletes and in permanent disability in 6 (19%). Increasing the minimum landing pad size and enforcing the rule requiring soft surfaces adjacent to the landing pads are the primary recommendations for preventing injuries. The authors discuss other rule and equipment changes that may help reduce the occurrence of future injuries.

High-risk stress fractures: evaluation and treatment.

Stress fractures are common overuse injuries seen in athletes and military recruits. The pathogenesis is multifactorial and usually involves repetitive submaximal stresses. Intrinsic factors, such as hormonal imbalances, may also contribute to the onset of stress fractures, especially in women. The classic presentation is a patient who experiences the insidious onset of pain after an abrupt increase in the duration or intensity of exercise. The diagnosis is primarily clinical, but imaging modalities such as plain radiography, scintigraphy, computed tomography, and magnetic resonance imaging may provide confirmation. Most stress fractures are uncomplicated and can be managed by rest and restriction from the precipitating activity. A subset of stress fractures can present a high risk for progression to complete fracture, delayed union, or nonunion. Specific sites for this type of stress fracture are the femoral neck (tension side), the patella, the anterior cortex of the tibia, the medial malleolus, the talus, the tarsal navicular, the fifth metatarsal, and the great toe sesamoids. Tensile forces and the relative avascularity at the site of a stress-induced fracture often lead to poor healing. Therefore, high-risk stress fractures require aggressive treatment.

Mechanisms of anterior cruciate ligament injury.

This study examined the mechanisms of anterior cruciate ligament (ACL) injury. In the first part of the study, using a comprehensive, standardized questionnaire, 89 athletes (100 knees) were interviewed about the events surrounding their ACL injury. A noncontact mechanism was reported in 71 (72%) knees and a contact injury in 28 (28%) knees; one patient was unsure if there was any contact. Most of the injuries were sustained at footstrike with the knee close to full extension. Noncontact mechanisms were classified as sudden deceleration prior to a change of direction or landing motion, while contact injuries occurred as a result of valgus collapse of the knee. Hamstring flexibility parameters revealed a statistically higher level of laxity in the injured athletes compared with a matched group of 28 controls. In the second part of the study, videotapes of 27 separate ACL disruptions were reviewed and confirmed that most noncontact injuries occur with the knee close to extension during a sharp deceleration or landing maneuver. Because the knee is in a position to allow the extensor mechanism to strain the ACL and maximum, eccentric muscle force conditions usually apply, the quadriceps may play an important role in ACL disruption. Passive protection of the ACL by the hamstring muscles may be reduced in patients with above-average flexibility.

Etiology and Prevention of Noncontact ACL Injury.

An understanding of the etiology and prevention of noncontact ACL injuries has lagged behind diagnosis and treatment. However, a growing research implicates hormonal, anatomic, environmental, and neuromuscular factors that may predispose athletes, particularly women, to these injuries. Specific factors may include estrogen levels, the shape of the intercondylar notch, playing style, and neuromuscular control of the quadriceps and hamstring muscles. Prevention programs that involve proprioception, plyometrics, strength training, and improved jumping, stopping, and turning techniques show promising results.

Tibia and fibula fractures in soccer players.

We performed a retrospective review of 31 athletes who sustained a fracture of the lower leg from a direct blow while playing soccer. Fifteen fractures involved both the tibia and fibula 11 only the tibia, and 5 only the fibula. Information was collected using a standardized questionnaire. The mean follow-up from the time of injury was 30 months. Injuries typically occurred in young, competitive athletes during game situations. The mechanisms were broadly classified into several categories: contact during a slide tackle (13, 42%), a collision with the goalkeeper (8, 26%), two opposing players colliding while swinging for a loose ball (7, 23%), or a player being kicked by a standing opponent (3, 10%). The majority of fractures (26, 90%) occurred while the athletes were wearing shin guards. The point of impact was with the shin guard prior to the fracture in 16 cases (62%). Return to competitive soccer averaged 40 weeks for combined tibia and fibula fractures, 35 weeks for isolated tibia fractures, and 18 weeks for isolated fibula fractures. Injuries were associated with a high incidence of major complications (12 out of 31, 39%), especially in concurrent tibia and fibula fractures (8 out of 15, 50%). These findings suggest that lower leg fractures in soccer players are serious injuries, often necessitating a prolonged recovery time. In addition, this study questions the ability of shin guards to protect against fractures.

Concussion incidence in elite college soccer players.

A unique aspect of soccer is the use of the head for directing the ball. The potential for resultant head injuries has been the focus of discussions worldwide. Prior work has attributed neuropsychologic deficits to the cumulative effects of heading, without evaluating concussion rates in soccer players. We prospectively studied the seven men's and eight women's varsity soccer teams in the Atlantic Coast Conference during two seasons to document concussion incidence. The 29 concussions diagnosed over the 2 years in 26 athletes, 17 (59%) concussions in men and 12 (41%) in women, resulted from contact with an opponent's head (8, 28%), elbow (4, 14%), knee (1, 3%), or foot (1, 3%); the ball (7, 24%); the ground (3, 10%); concrete sidelines (1, 3%); goalpost (1, 3%); or a combination of objects (3, 10%). Twenty concussions (69%) occurred in games; none resulted from intentional heading of the ball. The basic incidence was 0.96 concussions per team per season. The overall incidence was 0.6 per 1000 athlete-exposures for men, and 0.4 per 1000 athlete-exposures for women. By concussion grade, there were 21 (72%) grade 1, 8 (28%) grade 2, and no grade 3 concussions. These findings suggest that concussions are more common in soccer than anticipated and that acute head injuries may have potential for long-term neuropsychologic changes.

Leg injuries and shin guards.

Soccer players have a high risk of soft-tissue injuries to their legs. Fractures of the tibia and fibula represent a serious potential injury; despite this, the incidence of these fractures in soccer players is unknown. Shin guards have become the only protective devices that are required by international and collegiate soccer associations. Nonetheless, the protective ability of shin guards has only been studied to a limited extent. Shin guards are assumed to be most effective at reducing leg abrasions and contusions. The role of shin guards in protecting against fractures has yet to be determined. Further analysis of the clinical effectiveness and biomechanical properties of shin guards is necessary to reduce the rate of leg fractures.

Femoral stress fractures.

Stress fractures are common overuse injuries attributed to the repetitive trauma associated with vigorous weightbearing activities. A high index of suspicion is necessary to diagnose stress fractures of the femur because the symptoms may be vague. The precipitating factors, whether related to training errors or medical conditions, should be thoroughly evaluated. Early diagnosis of distraction femoral neck stress fractures is critical to avoid serious complications. Femoral shaft stress fractures have excellent healing potential when diagnosed early and treated non-operatively. Stress fractures of the femoral condyles are uncommon, but should be included in the differential of knee pain.

Diagnosis of biceps tendon dislocation by kinematic magnetic resonance imaging.

Biceps tendon dislocation is an uncommon condition that may be overlooked due to its association with more common shoulder pathology. Diagnosis may be further obscured by the difficulty of palpating the biceps tendon in a muscular or obese patient. We present a patient with a dislocating biceps tendon in which the diagnosis was confirmed by kinematic MRI.

Wrist arthroscopy.

Miniaturization of arthroscopic equipment has allowed wrist arthroscopy to emerge as a powerful surgical tool in orthopedic surgery. The magnified view of the arthroscope has provided a new understanding of carpal anatomy and disease. Arthroscopy improves surgeons' ability to diagnose wrist disorders and enables them to perform operative procedures with less morbidity than would occur in open procedures.

Management of traumatic cutaneous defects by using a skin-stretching device.

We report on nine orthopedic patients who underwent skin stretching to close 10 acute soft-tissue defects. The skin surrounding all wounds was stretched sufficiently to enable a primary closure. At an average of 9 weeks postoperatively, 9 of the 10 wounds healed without any complications. One wound dehisced postoperatively, but subsequently healed by secondary intention. The skin-stretching device eliminated the need for local or distant flap reconstruction in five skin defects and skin grafting in five wounds. Donor morbidity was avoided, the cosmetic appearance of the skin was maintained, and the in-hospital course of these patients was shortened.

Analgesic effect of intraarticular morphine, bupivacaine, and morphine/bupivacaine after arthroscopic knee surgery.

In a double-blind randomized fashion, 38 patients were divided into four groups according to the intraarticular injection received after arthroscopic surgery. Patients in group I (n = 7) received saline, group II (n = 10) morphine, group III bupivacaine, and group IV (n = 11) morphine and bupivacaine. Before surgery and at 0.5, 1, 1.5, 2, 6, and 24 h postoperatively, pain levels were recorded. In addition, postoperative supplemental i.v. morphine requested by the patient was tabulated. Results showed that the mean consumption of supplemental analgesia was lowest in the morphine/bupivacaine group. Although there was a statistically significant difference in pain scores between the saline group and the other three groups during the early postoperative period, there was no significant difference in pain scores between the morphine, bupivacaine, and morphine/bupivacaine groups. We conclude that postoperative, intraarticular injection of analgesics is beneficial in reducing pain levels. The combination of morphine/bupivacaine appears to be the most beneficial analgesic due to its low supplemental analgesic requirements postoperatively.

Acute compartment syndrome of the lower extremity secondary to noncontact injury.

We retrospectively reviewed the cases of three patients with injuries similar to the mechanism of an ankle sprain which resulted in compartment syndrome of the lower extremity. All three patients presented with sharp, proximal, anterolateral pain in the leg after an indirect, twisting injury. None of the injuries involved direct contact. Two of the three athletes initially presented to local hospitals, where the injury was misdiagnosed as an ankle sprain. The mechanism appears to be a muscle strain or tear with resultant hemorrhage in the compartment. All three patients returned to high-level athletics after prolonged recovery periods.

Arthroscopically-assisted anterior cruciate ligament reconstruction: a follow-up study.

In order to determine the early results of arthroscopically-assisted reconstruction of the anterior cruciate ligament (ACL), a comprehensive follow-up evaluation of 20 athletes with an average postoperative time of 26 months was performed. Clinical knee examination and measurements of thigh circumference, range of motion, and maximum quadriceps/hamstring strength were obtained. A detailed personal interview regarding activity level, subjective ratings, and functional status was conducted. At follow-up, anterior knee laxity was dramatically reduced, with no patients demonstrating a pivot-shift. Thigh circumference, range of motion, and maximum muscle strength were not significantly different than in the normal, uninvolved leg. Sixteen patients (80%) had returned to their preinjury activity level. Only one of the remaining four cited knee problems as part of the reason for not returning to preinjury athletic activities. Patients' subjective ratings were highly favorable. The findings in this study led to the conclusion that modifying traditional open methods of ACL reconstruction to an arthroscopically-assisted technique is an attractive surgical option.

Wrist flexor muscles of elite rowers measured with magnetic resonance spectroscopy.

We used phosphorus magnetic resonance spectroscopy to study skeletal muscle metabolism of trained vs. untrained humans. The forearms of highly trained rowers (n = 10) and age-matched controls were placed in a 1.9-T magnet so that the wrist flexor muscles were placed over a 4-cm transmitting and receiving coil. The subjects performed work by depressing a handle attached to an isokinetic ergometer. Relative concentrations of Pi, phosphocreatine (PCr), and ATP were measured along with intracellular pH. Measurements were made at rest, during steady-state and ramp exercise protocols, and during recovery from exercise. At rest the rowers had Pi/PCr that were not different from control. During steady-state exercise rowers (n = 4) had lower Pi/PCr at the same relative power levels, and the slope of the power vs. Pi-PCr curve was significantly greater than for controls. Rowers (n = 4) also had faster rates of PCr recovery after exercise than controls (T1/2 of 24 +/- 2.0 s for rowers and 47 +/- 8.4 s for controls) when power level was adjusted so that all subjects recovered from the same level of Pi/PCr. During a ramp exercise protocol, the initial slope of the power vs. Pi-PCr curve was greater in three of six rowers compared with controls and at the highest power level rowers had lower Pi/PCr values with less drop in pH. At the end of the ramp test, the same degree of muscle fatigue was associated with much lower levels of H2PO-4 (5.7 +/- 0.70 mM) in rowers compared with controls (13.0 +/- 1.8 mM).(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of muscle injury in humans with 31-P magnetic resonance spectroscopy.

Strenuous exercise can result in muscle injury that may persist for 2 weeks. Our purpose was to determine if muscle injury can be detected with 31-P magnetic resonance spectroscopy. Normal subjects performed repeated lengthening contractions with either arms or legs designed to result in mild muscle injury. One hour after the arm exercise, there was a significant increase in the inorganic phosphate to phosphocreatine ratio (Pi/PCr), with the maximum increase in Pi/PCr occurring 1 day postexercise (0.12 +/- 0.01 to 0.21 +/- 0.05). Pi/PCr remained elevated for 3-10 days. Similar results were seen following the leg exercise protocol. ATP/(Pi + PCr) decreased in all the arm exercised subjects. Exercise protocols that did not contain lengthening contractions did not result in changes of Pi/PCr or ATP/(Pi + PCr). Patients with various neuromuscular diseases with evidence of muscle damage (elevated CK, muscle soreness, and histopathological findings) also showed increased Pi/PCr at rest. We conclude that elevated Pi/PCr at rest can reflect nonspecific muscle damage in normal and diseased subjects.