Total knee arthroplasty in patients 55 years old or younger. 10- to 17-year results

Seventy-four consecutive total knee arthroplasties in 54 patients who were 55 years of age or younger (average age 43 years) were reviewed. All patients had a minimum followup of 10 years with an average followup of 13 years (range, 10-17 years). No patients died or were lost to followup. The preoperative diagnosis was rheumatoid arthritis in 47, gonarthrosis in 12, posttraumatic arthritis in six, osteonecrosis in three, hemophilia in two, and one patient each with pigmented villonodular synovitis, tuberculosis, systemic lupus erythematosus, and achondroplasia. The knee score improved from an average of 36 points (range, 10-80 points) preoperatively to 84 points (range, 37-100 points) at latest followup. The functional score improved from 45 points (range, 0-100 points) to 60 points (range, 0-100 points) at latest followup. Two patients had their implants revised: one at 3 years because of ligamentous laxity and one at 13 years because of aseptic loosening of the tibial component. There were no deep infections. There were no radiographically loose implants at latest followup. The implant survival to revision at 10 years was estimated at 99% (confidence limit, 96%-100%). The implant survival to revision at 15 years was estimated at 95% confidence limit, 88%-100%). Cemented total knee arthroplasty in the young patient is a reliable procedure and has excellent results at 13-year followup with an estimated survivorship of 99% at 10 years.

On-field examination and care: an emergency checklist

The on-site physician at an athletic event must be able to recognize life-threatening conditions, provide initial care for all conditions, and direct transport if needed. Preparation is critical for avoiding catastrophe; it involves establishing communication and protocol beforehand, as well as developing a mental checklist for assessing injuries. After ensuring an adequate airway, breathing, and circulation, the examiner determines the patient's level of consciousness, mental status, and symptoms and assesses for neck injury. The physician may then need to prepare for emergency transport or for further evaluation on the sidelines.

Tardy sciatic nerve palsy following apophyseal avulsion fracture of the ischial tuberosity. Case report

This 4 1-year-old man presented with a 2-year history of symptoms and signs of sciatic nerve compression. Imaging studies revealed a large ossified fragment within the biceps muscle of the thigh abutting the sciatic nerve at the level of the lesser trochanter. The bony fragment resulted from an unrecognized apophyseal avulsion fracture of the ischial tuberosity, which the patient had sustained while sprinting 27 years earlier. External neurolysis of the sciatic nerve and excision of the mass led to a successful outcome.

Out of hospital cardiac arrest and associated injury

Three patients are described who sustained injuries around the time of a collapse that led to out of hospital cardiac arrest. In this group of patients the importance of taking a complete medical history and recording the circumstances of the syncopal episode cannot be overemphasised. If cardiac output is successfully restored the possibility of occult traumatic injury must be considered in high risk patients.

Eicosanoids in sickle cell disease: potential relevance of 12(S)-hydroxy-5,8,10,14-eicosatetraenoic acid to the pathophysiology of vaso-occlusion

The monohydroxyeicosanoid 12(S)-hydroxy-5,8,10,14-eicosatetraenoic acid (12-HETE), which is derived from oxygenation of arachidonic acid by 12-lipoxygenase, is one of the major metabolites in platelets. In a recent study, we have showed that this eicosanoid stimulated basal sickle-red-cell-endothelial-cell adhesion. To understand the pathophysiologic significance of 12-HETE, we measured the levels of this eicosanoid in plasma and urine from children with sickle cell disease. We found that as compared with controls, plasma 12-HETE levels are increased in patients with sickle-cell disease in the steady state, and are increased further during vaso-occlusive crises. Urinary 12-HETE levels were also increased during the steady state. We also assessed plasma levels of soluble P-selectin (another potential marker for platelet activation), and found changes in the levels of this marker similar to those seen with plasma 12-HETE. In additional studies, we found that 12-HETE enhanced hypoxia-induced sickle-red-cell-endothelial adherence, and that this effect was mediated by potentiation of agonist-induced upregulation of the expression of the mRNA for vascular cell adhesion molecule-1 (VCAM-1) in endothelial cells. Because 12-HETE appears to enhance both basal and agonist-induced sickle-red-cell adhesion, this metabolite could potentially play a role in the pathogenesis of the vaso-occlusive crisis (VOC) in sickle-cell disease.

Psychologic, situational, and physiologic variables and on-ice performance of youth hockey goalkeepers

OBJECTIVE

To determine the relationship between psychologic, situational, and physiologic variables and on-ice performance of youth hockey goalkeepers.

DESIGN

This study was structured to identify relationships and predictors of goalie performance.

MATERIAL AND METHODS

Because athletes playing solo positions in team sports have not been analyzed in depth in terms of precompetition anxiety and because goalkeeper performance is critical to game outcome, we undertook a study of 43 goalies at a hockey camp. These goalies completed psychometric inventories to assess trait and state anxiety, confidence, life stress, and social support. Holter monitors measured heart rate while the goalies rotated through on-ice stations. Goalies were videotaped at the puck-shooting machine station, and performance (percent saves) was calculated.

RESULTS

Trait (somatic) anxiety and positive mood state (ability to share) had different but significant relationships with on-ice performance. Heart rates ranged from 88 to 208 beats/min at the on-ice stations. Mean heart rate for older goalies (14 to 18 years of age) was 164 beats/min at the puck-shooting machine and 176 beats/min at other stations such as the slap-shot station.

CONCLUSION

Older goalies performed well at a high level of arousal. Better performing goalies were more experienced, had faster heart rates "in the net," and had lower scores on all measures of anxiety.

Predictors of injury in ice hockey players. A multivariate, multidisciplinary approach

Eighty-six male high school ice hockey players participated in this prospective study to determine both the incidence of injury in high school ice hockey and the influence of physical, situational, and psychosocial factors. Physical factors included height, weight, vision, previous injuries, musculoskeletal abnormalities, and injuries present at the time of screening evaluations. Situational factors examined were level of participation, playing time, player position, and games versus practices. Psychosocial factors such as confidence, stress, social support, positive states of mind, and mood states were also examined to determine their influences on injury. Twenty-seven injuries occurred during the 1994 to 1995 season. As hypothesized, the overall incidence of injury in high school hockey games (34.4 per 1000 player-game hours) was less than the incidence of injury in Junior A hockey (96.1 per 1000 player-game hours) and was more than previously reported for Bantam youth hockey (10.9 per 1000 player-game hours). Injuries occurred more often in games than in practices, usually as a result of collisions. Physical factors such as player position and previous injuries did not significantly predict injuries, but players in the high playing time group were more likely to be injured. Psychosocial factors of low vigor and high fatigue as measured by the Incredibly Short Profile of Mood States (ISPOMS) significantly predicted high school ice hockey injuries.

Valgus-varus motion of the knee in normal level walking and stair climbing

OBJECTIVE: The knee valgus-varus moment and the knee angles were compared between normal level walking and stair climbing. DESIGN: Ten healthy subjects were tested for ascent, descent, and level walking. BACKGROUND: An understanding of the normal valgus-varus motion of the knee during stair climbing is needed to apply biomechanical analysis of stair climbing as a evaluation tool for knee osteoarthritis patients. METHODS: A motion analysis system, three force plates, and a flight of stairs were used to collect kinematic and kinetic data. The knee angles and moments were calculated from the collected kinematic and kinetic data. RESULTS: The knee varus angle for the maximum knee valgus moments in stair climbing was significantly greater than that in level walking. The knee valgus moment was significantly correlated to ground reaction forces and knee valgus-varus angle during stair climbing and level walking. CONCLUSIONS: There is a coupling between the knee valgus-varus motion and flexion-extension motion. Ground reaction forces are the major contributors to the within-subject variation in the knee valgus-varus moment during stair climbing and level walking. The knee valgus-varus angle is a major contributor to the between-subject variation in the knee valgus moment during stair climbing and level walking.

Comparison of intersegmental tibiofemoral joint forces and muscle activity during various closed kinetic chain exercises

The purpose of this study was to analyze intersegmental forces at the tibiofemoral joint and muscle activity during three commonly prescribed closed kinetic chain exercises: the power squat, the front squat, and the lunge. Subjects with anterior cruciate ligament-intact knees performed repetitions of each of the three exercises using a 223-N (50-pound) barbell. The results showed that the mean tibiofemoral shear force was posterior (tibial force on femur) throughout the cycle of all three exercises. The magnitude of the posterior shear forces increased with knee flexion during the descent phase of each exercise. Joint compression forces remained constant throughout the descent and ascent phases of the power squat and the front squat. A net offset in extension for the moment about the knee was present for all three exercises. Increased quadriceps muscle activity and the decreased hamstring muscle activity are required to perform the lunge as compared with the power squat and the front squat. A posterior tibiofemoral shear force throughout the entire cycle of all three exercises in these subjects with anterior cruciate ligament-intact knees indicates that the potential loading on the injured or reconstructed anterior cruciate ligament is not significant. The magnitude of the posterior tibiofemoral shear force is not likely to be detrimental to the injured or reconstructed posterior cruciate ligament. These conclusions assume that the resultant anteroposterior shear force corresponds to the anterior and posterior cruciate ligament forces.

Vascular cell adhesion molecule-1 is involved in mediating hypoxia-induced sickle red blood cell adherence to endothelium: potential role in sickle cell disease

We investigated the effects of hypoxia on red blood cell (RBC)-endothelial cell (EC) adherence and the potential mechanism(s) involved in mediating this effect. We report that hypoxia significantly increased sickle RBC adherence to aortic EC when compared with the normoxia controls. However, hypoxia had no effect on the adherence of normal RBCs. In additional studies, we found that the least dense sickle RBCs containing CD36+ and VLA-4+ reticulocytes were involved in hypoxia-induced adherence. We next evaluated the effects of hypoxia on the expression of EC surface receptors involved in RBC adherence to macrovascular ECs, including vascular cell adhesion molecule-1 (VCAM-1), intracellular adhesion molecule-1 (ICAM-1), and the vitronectin receptor (VnR). Hypoxia upregulated the expression of both VCAM-1 and ICAM-1, whereas no effect on VnR was noted. Potential involvement of VCAM-1 and ICAM-1 in mediating hypoxia-induced sickle RBC-EC adhesion was next investigated using monoclonal antibodies against these receptors. Whereas anti-VCAM-1 had no effect on basal adherence, it inhibited hypoxia-induced sickle RBC adherence in a concentration-dependent manner, with 50% to 75% inhibition noted at 10 to 60 micrograms/mL antibody (n = 6, P < .05 to P < .01). Anti-ICAM-1 (10 to 60 micrograms/mL, n = 8) had no effect on either basal or hypoxia-induced adherence. As noted in the bovine aortic ECs, hypoxia stimulated the adherence of sickle RBCs to human retinal capillary ECs, and this response appeared to be mediated via mechanisms similar to those observed with macro-endothelium, ie, via the adhesive receptor combination VCAM-1-VLA-4. Our studies show that hypoxia enhances sickle RBC adhesion to both macrovascular and human microvascular ECs via the adhesive receptor VCAM-1. Our findings are of interest because hypoxia is an integral part of the pathophysiology of the vaso-occlusive phenomenon in sickle cell anemia.

Sickle red blood cells stimulate endothelial cell production of eicosanoids and diacylglycerol

The effects of sickle red cell-endothelial cell interaction on endothelial cell arachidonic: acid (AA) mobilization, eicosanoid release, and diacylglycerol (DAG) production were evaluated by using bovine aortic endothelial cells. We have shown that coincubation of washed red blood cells (RBCs) from patients with sickle cell disease with endothelial cells stimulate AA release (90% increase as compared with buffer controls, n = 8, p < 0.002). Released AA was mobilized from membrane phosphatidylcholine and phosphatidylserine and was converted to eicosanoids via the cyclooxygenase and lipoxygenase pathways in increased amounts in the presence of sickle erythrocytes. The production of prostacyclin and 15-hydroxyeicosatetraenoic acid (15-HETE) were increased by 78% (p < 0.01) and 103% (p < 0.025), respectively, as shown by both chromatographic and immunoassay procedures. Sickle erythrocytes also stimulated the hydrolysis of endothelial cell phosphoinositides, including phosphatidylinositol-mono-phosphate (p < 0.03) and phosphatidylinositol-bis-phosphate (p < 0.006). This response was accompanied by a significant increase in the production of DAG (50% increase as compared with buffer control, n = 8, p < 0.025). In contrast, coincubation of washed erythrocytes from normal healthy donors with endothelial cells had no significant effect on endothelial cell phospholipid turnover. When the sickle RBC-induced biochemical changes in endothelial cells were contrasted with those observed with normal RBCs, the ability of sickle RBCs to induce AA mobilization and the production of mono-HETEs and DAG was markedly increased (p = 0.05 to p < 0.025). Because 15-HETE is a pro-adhesinogenic eicosanoid and DAG is an endogamous activator of protein kinase C, an enzyme involved in modulating cell surface adhesive properties, both 15-HETE and DAG could potentially play a role in the vascular pathophysiology of sickle cell disease.

Ultrasound assessment and conservative management of inversion injuries of the ankle in children: plaster of Paris versus Tubigrip

We studied 45 children who presented with an inversion injury of the ankle. The clinical signs suggested injury to the distal growth plate of the fibula, but the plain radiographs appeared normal. Ultrasound examination of the joint in 40 patients showed a subperiosteal haematoma consistent with a growth-plate injury in 23 (57.5%). Children who had been treated with a tubular bandage and crutches by random selection had a mean time to return of normal activity of 14.22 days compared with 21.60 days for those treated with a plaster-of-Paris cast (t=3.60, p=0.0032; d=7.38, 95% CI 3.0 to 11.8). We conclude that children with inversion ankle injuries who have clinical signs of injury to the distal fibular growth plate but a normal radiological appearance, should be treated with a tubular bandage and crutches.

ULTRASOUND ASSESSMENT AND CONSERVATIVE MANAGEMENT OF INVERSION INJURIES OF THE ANKLE IN CHILDREN

We studied 45 children who presented with an inversion injury of the ankle. The clinical signs suggested injury to the distal growth plate of the fibula, but the plain radiographs appeared normal. Ultrasound examination of the joint in 40 patients showed a subperiosteal haematoma consistent with a growth-plate injury in 23 (57.5%). Children who had been treated with a tubular bandage and crutches by random selection had a mean time to return of normal activity of 14.22 days compared with 21.60 days for those treated with a plaster-of-Paris cast (t = 3.60, p = 0.0032; d = 7.38, 95% CI 3.0 to 11.8).

We conclude that children with inversion ankle injuries who have clinical signs of injury to the distal fibular growth plate but a normal radiological appearance, should be treated with a tubular bandage and crutches.

Impaired mobilization of intracellular calcium in neonatal platelets

Abnormalities in platelet functions including aggregation and the release reaction have long been recognized to be present in neonatal platelets. Because calcium is an important mediator of many platelet functions, we have investigated the mobilization of calcium in neonatal platelets. All umbilical cord blood samples were obtained from healthy, full term gestations. Changes in cytoplasmic calcium levels were monitored using Fura-2 as a fluorescent probe. Fura-2-loaded washed platelets were stimulated with the agonists collagen (2 micrograms/mL) or thrombin (1.0 U/mL). When compared with adult controls, intracellular calcium release in the platelets of the neonate was significantly impaired in response to these agonists. Mean levels for calcium release in adults versus neonates in response to collagen were 168 +/- 120 nM (+/-SD, n = 10), and 61 +/- 69 nM (n = 7, p < 0.05). A decrease in response to thrombin was also observed [1296 +/- 503 nM (n = 8) in adults versus 603 +/- 482 nM (n = 7) in neonates, p < 0.025]. Results similar to those observed with unpaired neonatal and adult platelets were also obtained when neonatal platelets (n = 5) were compared with their paired maternal controls. In further studies, we have documented that the calcium content of the dense tubular system was normal in the neonatal platelet, indicating that the observed impairment in calcium mobilization in the neonate was not due to a decrease in calcium stores. The previously documented abnormalities in neonatal platelet function appear to be due to the impaired mobilization of this important intracellular mediator.

In-line skating injuries

OBJECTIVE

To assess the type and site of injuries associated with in-line skating in patients encountered during an 18-month period.

DESIGN

We retrospectively reviewed the medical records of patients in our emergency department and Sports Medicine Center with injuries that had resulted from in-line skating between July 1992 and December 1993.

MATERIAL AND METHODS

A computer search was conducted to identify medical records on which in-line skating was denoted as the mechanism of injury. The records were then manually reviewed to confirm that the injury had occurred during in-line skating. The patient's sex, age, type of injury, and injured body part were recorded.

RESULTS

During the designated study period, 32 in-line skating injuries were recorded in 32 patients (19 female and 13 male skaters). The mean age of the study group of injured skaters was 17 years (range, 6 to 46). An upper extremity was involved in 78% of all injuries, and the wrist was the body part most often injured (56%). A lower extremity was involved in 16% of all injuries, including two that were severe. Of the 32 injuries, 62% were fractures, and surgical treatment was necessary for only 1 injury during the study period.

CONCLUSION

In this study, in-line skating injuries most commonly involved the upper extremities. Fractures, particularly of the distal radius, were the most common type of injury. Lower extremity trauma was less frequent, but severe injuries can occur. Further prospective studies are needed.

Injuries in Junior A ice hockey. A three-year prospective study

This 3-year prospective cohort observational analysis of elite amateur hockey players ranging in age from 17 to 20 years on a United States Hockey League team describes ice hockey injuries using a strict definition of injury, standardized reporting strategies, and diagnosis by a team physician. One hundred forty-two injuries were recorded for an on-ice injury rate of 9.4 per 1000 player hours. A player was 25 times more likely to be injured in a game (96.1 per 1000 player-game hours) than in practice (3.9 per 1000 player-practice hours). Game-related injuries were more frequent in the third period, and practice-related injuries occurred more often in the first third of the season. Collisions represented 51% of the total injuries. The most common types of injuries were strains, lacerations, contusions, and sprains. The face and the shoulder were most frequently injured. A facial laceration was the most common injury; acromioclavicular joint sprain was the second most common injury. Facial lacerations typically occurred in games and were stick related. Further research is necessary to determine if injuries in Junior A amateur ice hockey can be reduced by mandatory full facial protection, enforcement of existing rules, improvement in shoulder pad design, and by focusing more attention on stretching programs.

Sickle cell vaso-occlusive crisis is associated with abnormalities in the ratio of vasoconstrictor to vasodilator prostanoids

Plasma levels of 6-keto-prostaglandin F1 alpha (6kPGF1 alpha) and thromboxane (Tx) B2 have been assessed in sickle cell disease (SCD) with discrepant results. Inasmuch as direct measurement of plasma prostanoids is fraught with the problem of interfering substances, we assessed plasma 6kPGF1 alpha and TxB2 levels in patients with SCD by RIA after extraction of eicosanoids and separation by HPLC. We demonstrate that the 6kPGF1 alpha and TxB2 levels in children with SCD in steady state as well as in vaso-occlusive crisis (VOC) are significantly lower when compared with those from age-matched controls. The VOC plasma 6kPGF1 alpha and TxB2 levels were, however, significantly elevated when compared with those from children in steady state. Changes similar to those noted with unpaired plasma samples were also observed when paired steady state and VOC plasmas from the same patients were assessed. The ratio of TxB2 to 6kPGF1 alpha was, however, significantly elevated in patients with SCD in crisis when compared with eicosanoid ratios obtained during steady state. In an attempt to understand whether the abnormality in 6kPGF1 alpha was due to an impairment in endothelial cell prostacyclin-regenerating ability, we compared the ability of plasma from controls and children with SCD to activate arachidonic acid (AA) release and prostacyclin production by [14C]AA-prelabeled bovine aortic endothelial cells. Our results suggest that the decreased 6kPGF1 alpha levels in plasma from children with SCD was not due to an effect on substrate AA release but rather a modulatory effect of sickle plasma components on endothelial cell cyclooxygenase activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Medical coverage for multievent sports competition: a comprehensive analysis of injuries in the 1994 Star of the North Summer Games

OBJECTIVE

To determine the incidence and type of requests for medical assistance and the treatment required in 21 sports at the 1994 Star of the North Summer Games and to develop a plan, based on these findings, for efficient allocation of medical supplies and staff.

DESIGN

We reviewed our experience with a large multisport amateur athletic event and analyzed the pattern of injuries for participants in the various sports.

MATERIAL AND METHODS

Injury evaluation forms and medical supply kits were given to the health-care volunteers, who received preliminary instructions on classifications and definitions of injuries and on appropriate completion of the forms. When a medical contact occurred, an evaluation form was completed. The data from these forms were subsequently compiled and analyzed.

RESULTS

Of 6,243 athletes who participated in the 1994 Star of the North Summer Games, 55 (0.88%) received medical attention (2 officials also required medical assistance). The sports with the greatest number of medical contacts were soccer and track and field--31 and 16 contacts for medical assistance, respectively. The lower extremities were the anatomic site most frequently involved in injury (62% of the medical contacts). The most common types of injury were contusions, strains, and sprains.

CONCLUSION

Because few injuries were sustained and most were of minor severity, basic medical supplies (such as ice bags and compression wraps) were sufficient. For locations with a scarcity of medical personnel, a triage system can be established in which athletic trainers or registered nurses manage the initial assessments and refer cases, as needed, to physicians for specialized care. An effective communication system can also considerably reduce volunteer hours.

Fetal bleeding in neonatal alloimmune thrombocytopenia mediated by anti-PlAl is not associated with inhibition of fibrinogen binding to platelet GPIIb/IIIa

Antibody directed against the platelet-specific alloantigen, PlAl, is the most frequently reported cause of two syndromes, post-transfusion purpura (PTP), and neonatal alloimmune thrombocytopenia (NAIT). Numerous reports have indicated that anti-PlAl also has the ability to block certain responses of platelets to stimulation, including fibrinogen binding, platelet aggregation, and serotonin release. Because the PlAl epitope is located on platelet membrane glycoprotein (GP) IIb/IIIa that also contains the fibrinogen receptor, these effects may be mediated by antibody binding at or near the fibrinogen receptor site. This study examines the capacity of anti-PlAl from patients with PTP and from mothers of infants affected by the NAIT to block the binding of radio-labeled fibrinogen to washed human platelets stimulated by ADP and epinephrine. In six of the seven PTP patients, there was inhibition of fibrinogen binding, ranging from 28% to 84% inhibition. In contrast, all anti-PlAl sera from nine mothers of infants with NAIT, including four with intracranial hemorrhage, failed to inhibit fibrinogen binding. Despite the generally higher anti-PlAl titers of the PTP sera, the ability to inhibit fibrinogen binding did not appear attributable to antibody titers. These results suggest that interference with fibrinogen binding to platelets by maternal anti-PlAl does not underlie the increased risk of bleeding in NAIT, whereas inhibitory activity directed against fibrinogen binding appears to be a characteristic feature of the sera from PTP patients.

Arachidonic acid metabolites are involved in mediating red blood cell adherence to endothelium

As an initial investigation into the possible role of endothelial cell (EC) lipoxygenase and cyclooxygenase metabolites in the adherence of red blood cells (RBCs) to ECs, we evaluated the effect of nordihydroguaiaretic acid, (NDGA; 10 mumols/L, BW755c (30 mumols/L), aspirin (100 mumols/L), and indomethacin (10 mumols/L) on RBC-EC adherence using a static incubation system and 51Cr-labeled RBCs. NDGA and 3-amino-L-[3'-(trifluoromethyl)phenyl]-2-pyrazoline inhibitors of both the lipoxygenase and cyclooxygenase pathways, significantly decreased basal adhesion of RBCs to fetal bovine aortic ECs, whereas aspirin and indomethacin, selective inhibitors of the cyclooxygenase pathway, stimulated the adherence process. The inhibitor effect appeared to be mediated via an effect on EC functions, since preincubation of ECs with NDGA, in contrast to RBC-NDGA preincubation, inhibited the adherence process. Because bovine aortic ECs generate mainly prostacyclin and 15-HETE from arachidonic acid (AA) via the cyclooxygenase and the lipoxygenase pathways respectively, the role of these products (100 pmol/L to 1 mumol/L) on the adhesive process was further assessed. 15-HETE potentiated basal adhesion of RBCs to bovine aortic ECs in a concentration-dependent manner, with maximal responses of approximately 50% to 150% over baseline noted at concentrations between 1 and 100 nmol/L 12-HETE, a structural isomer of 15-HETE and the major platelet lipoxygenase product, also stimulated RBC adherence. In contrast, prostacyclin (assessed using carbacyclin, a stable synthetic analog of prostacyclin with similar biologic properties) had no significant effect on this process. In further studies, we demonstrated that the 12-HETE-induced adherence of sickle RBCs was mediated via an up-regulation of the vitronectin receptor on bovine aortic endothelium. Because microvascular capillary endothelium is the surface most likely to encounter erythrocytes in vivo, we extended our studies to human retinal capillary ECs to assess the involvement of eicosanoids in sickle RBC-microvessel adhesion. As with bovine aortic ECs, aspirin stimulated and NDGA decreased the adherence of sickle RBCs to human retinal capillary endothelium. These microvascular ECs generated prostacyclin, HHT, 15-HETE, and 15-HPETE from endogenous AA. Although carbacyclin and HHT had no effect on the adherence process, both 15-HETE and 15-HPETE (10 pmol/L to 100 nmol/L) stimulated RBC adhesion to capillary endothelium. Our studies document a role for the lipoxygenase metabolites in modulating basal adhesion of RBCs to both macrovascular and microvascular endothelium; the major cyclooxygenase metabolites appear to play no role in this process.

Injuries in youth ice hockey: a pilot surveillance strategy

OBJECTIVE

To determine the incidence and type of injuries in youth hockey players during practice and games as well as to test the applicability of the current methods to a national surveillance study of youth hockey injuries.

DESIGN

During the 1993 to 1994 season, we undertook a prospective observational analysis of youth hockey players on four competitive teams at three levels of participation: Squirt, Peewee, and Bantam.

MATERIAL AND METHODS

In a study group of 66 youth hockey players, types and anatomic sites of injury, mechanisms of injury, player position affected, and occurrence of injuries during practice or games were determined and analyzed statistically. An injury was strictly defined, standardized reporting strategies were used, and a single physician examined all injured athletes and made the diagnoses.

RESULTS

A total of 14 injuries occurred during the season. The on-ice injury rate (per 1,000 player-hours) was 1.0 at the Squirt level (ages 9 and 10 years), 1.8 at the Peewee level (ages 11 and 12 years), and 4.3 at the Bantam level (ages 13 and 14 years). No game injuries and only one mild practice injury occurred in Squirt players (N = 16), and only two mild injuries occurred during practice sessions for Peewees (N = 17). No differences were noted between practice injury rates at the various levels; all recorded game injuries occurred only in Bantam players (N = 33). The most common types of injuries were contusions, fractures, strains, and sprains. The arm and shoulder were most frequently injured.

CONCLUSION

Further research is necessary to determine whether injuries in youth ice hockey can be reduced by changes in playing rules, enforcement of existing rules, improvements in protective equipment, alteration in coaching techniques, and institution of educational programs.

Participation in sports after hip and knee arthroplasty: review of literature and survey of surgeon preferences

OBJECTIVE

To summarize previously published findings and to present the opinions of a group of reconstructive orthopedic surgeons from a single institution on participation in sports after hip or knee arthroplasty.

DESIGN

We reviewed the literature pertaining to participation in sports after hip or knee arthroplasty and surveyed a group of orthopedic surgeons about their recommendations for resumption of various sports activities by patients who had undergone total hip or knee arthroplasty.

MATERIAL AND METHODS

A computerized literature search was performed, and salient issues about participation in sports after joint replacement procedures were synthesized. At the Mayo Clinic, 28 orthopedic surgeons (13 consultants and 15 fellows or residents) completed a single-page questionnaire that requested a recommendation ("yes," "no," or "depends") about patients resuming participation in 28 common sports after recovery from total hip or knee arthroplasty. Staff surgeon responses were compared with responses from fellows and residents by using the Mann-Whitney U test. Sports in which 75% of surgeons would not allow participation were identified as "not recommended," whereas sports in which 75% of surgeons would allow participation were labeled as "recommended."

RESULTS

Fellows and residents were less likely than staff surgeons to allow return to cross-country skiing after total knee arthroplasty. Otherwise, responses from consultant surgeons and from fellows and residents did not differ significantly. Recommended sports included sailing, swimming laps, scuba diving, cycling, golfing, and bowling after hip and knee replacement procedures and also cross-country skiing after knee arthroplasty. Sports not recommended after hip or knee arthroplasty were running, waterskiing, football, baseball, basketball, hockey, handball, karate, soccer, and racquetball.

CONCLUSION

After hip or knee arthroplasty, participation in no-impact or low-impact sports can be encouraged, but participation in high-impact sports should be prohibited.

Isolated rupture of the patellar tendon in athletes

The purpose of this study was to review patellar tendon ruptures in athletes treated with surgical repair. Six patellar tendon ruptures in five athletic patients were identified at our institution between 1980 and 1990. All patients had operative debridement and primary repair of the ruptured patellar tendon using nonabsorbable sutures passed through patellar drill holes at an average of 2.5 days after injury. Personal interview, physical examination, roentgenographic evaluation, and isokinetic strength testing were performed at an average of 6 years after surgery. At final followup, no patient had complaints referable to the patellar tendon repair; all were able to achieve their premorbid levels of sports at an average of 18 months after injury. No patient thought that the surgically repaired knee was unstable or activity-limiting. All patients demonstrated full range of motion and strength equal to or greater than that of the noninjured side. One patient required an arthroscopic lateral release for lateral patellar facet pressure syndrome with an excellent result. No complications occurred; no other reoperations were required. Complete disruption of the patellar tendon is an uncommon injury in athletic individuals without predisposing medical conditions. After acute operative repair and aggressive rehabilitation, an excellent and enduring functional outcome can be expected.