Systematic review and meta-analysis of external ventricular drain placement accuracy and narrative review of guidance devices

BACKGROUND

Insertion of external ventricular drain (EVD) is one of the most common neurosurgical procedures performed worldwide. This is generally performed freehand, on the basis of anatomical landmarks. There is significant variability in the reported accuracy of freehand placement, lacking Level I evidence. We present the first meta-analysis of freehand EVD placement accuracy and technologies or techniques to enhance accuracy.

METHODS

We report a systematic review of the Pubmed, Embase, and Cochrane Central databases according to MOOSE (Meta-analysis Of Observational Studies) guidelines. 37 studies were included for qualitative analysis and 19 studies (2983 cases) for quantitative analysis.

RESULTS

There is substantial heterogeneity in the outcome measures used to report EVD placement accuracy. Of those nineteen studies reporting accuracy using the Kakarla grading system the mean rate of ideal ipsilateral frontal horn placement was 73% (standard deviation ±7%). The use of formal stereotaxic guidance is consistently reported to improve accuracy to >90%, although with variable outcome measures. However, the reported efficacy of other guidance devices or techniques is highly variable. The quality of studies directly comparing all existing non-stereotaxic devices with freehand EVD placement is poor and precludes any assertion of superiority to freehand insertion.

CONCLUSIONS

We provide the first meta analysis of freehand placement accuracy. There is insufficient data to perform a meta-analysis of the relative efficacy of interventions to improve accuracy. Qualitative synthesis of reports of stereotaxic guidance is suggestive of higher accuracy than freehand placement.

A randomized controlled trial of fixed- versus mobile-bearing total knee arthroplasty: a follow-up at a mean of ten years

Aims

It has been suggested that mobile-bearing total knee arthroplasty (TKA) might lead to better outcomes by accommodating some femorotibial rotational mismatch, thereby reducing contact stresses and polyethylene wear. The aim of this study was to determine whether there is a difference between fixed- and mobile-bearing versions of a contemporary TKA with respect to durability, range of movement (ROM) and function, ten years postoperatively.

Patients and Methods

A total of 240 patients who were enrolled in this randomized controlled trial (RCT) underwent a primary cemented TKA with one of three tibial components (all-polyethylene fixed-bearing, modular metal-backed fixed-bearing and mobile-bearing). Patients were reviewed at a median follow-up of ten years (IQR 9.2 to 10.4).

Results

There was no difference in durability, as measured by survivorship free of revision for any reason, nor in mean maximal ROM at ten years (p = 0.8). There was also no difference in function, as measured by Knee Society (KS) function scores (p = 0.63) or the prevalence of patellar tilt (p = 0.12).

Conclusion

In this clinical RCT, the mobile-bearing design of TKA was found to be reliable and durable, but did not provide better maximum knee flexion, function or durability ten years postoperatively compared with a posterior-stabilized, fixed-bearing design incorporating either an all-polyethylene or a modular-metal-backed tibial component. Cite this article: Bone Joint J 2018;100-B:925-9.

Traumatic Trabecular Lesions Observed on MR Imaging of the Knee

Examinations carried out on 302 consecutive patients with MR of the knee between January 1988 and March 1989 were reviewed for detection of trabecular lesion. Twenty-seven patients found presenting trabecular lesion were further reviewed with specific reference to their activity level and need for specific therapy to determine the clinical significance of the trabecular lesion. Twenty-one of the trabecular lesions were in the femur, 5 were in the tibia, and one was in the fibula. Three of them were associated with a direct trauma, 12 with a valgus type injury, 3 with pure rotation mechanism, and 5 with a combination of valgus and rotation. In 17 cases trabecular lesion was a single finding, in 10 cases it was associated with some ligamentous tear. At the follow-up visit, 26 of the 27 patients with trabecular lesion had no symptoms, and the patient with moderate knee symptoms had had similar knee symptoms prior to the accident due to an osteochondral defect. We conclude that a trabecular lesion in an MR image is a benign bone change associated with knee trauma which heals without sequelae.

A phase-specific neuroimmune model of clinical depression

Immune dysfunction and pro-inflammatory states in particular have been implicated in the aetiology and pathogenesis of depression. Whilst the onset of an episode and certain symptoms of depression appear well explained by this inflammatory model, the underpinnings of the episodic and progressive nature, as well as relapse and remission status in depression require attention. In this review it is suggested that additional immune factors beyond pro- and anti-inflammatory cytokines may effectively contribute to the understanding of the neurobiology of clinical depression. Considering neurobiological effects of immunomodulatory factors such as T cells, macrophages, microglia and astrocytes relevant to depression, we suggest a neuroimmune model of depression underpinned by dynamic immunomodulatory processes. This perspective paper then outlines a neuroimmune model of clinical phases of depression in an attempt to more adequately explain depression-like behaviours in pre-clinical models and the dynamic nature of depression in clinical populations. Finally, the implications for immunomodulatory treatments of depression are considered.

Heme induces endothelial tissue factor expression: potential role in hemostatic activation in patients with hemolytic anemia

OBJECTIVES

We explored the possibility that heme, an inflammatory mediator and a product of intravascular hemolysis in patients with hemolytic anemia including sickle cell disease, could modulate hemostasis by an effect on endothelial tissue factor (TF) expression.

METHODS

Levels of TF mRNA, protein and procoagulant activity were measured in heme-treated endothelial cells.

RESULTS

Heme induces TF expression on the surface of both macrovascular and microvascular endothelial cells in a concentration-dependent manner, with 12-fold to 50-fold induction being noted (enzyme-linked immunosorbent assay) between 1 and 100 microm heme (P < 0.05). Complementary flow cytometry studies showed that the heme-mediated endothelial TF expression was quantitatively similar to that of tumor necrosis factor-alpha (TNF-alpha). Heme also upregulated the expression of TF mRNA (8-fold to 26-fold), protein (20-fold to 39-fold) and procoagulant activity (5-fold to 13-fold) in endothelial cells in a time-dependent manner. The time-course of heme-mediated TF antigen expression paralleled the induction of procoagulant activity, with antibody blocking studies demonstrating specificity for TF protein. Interleukin (IL)-1alpha, and TNF-alpha are not involved in mediating the heme effect, as antibodies against these cytokines and IL-1-receptor antagonist failed to block heme-induced TF expression. Inhibition of heme-induced TF mRNA expression by sulfasalazine and curcumin suggested that the transcription factor nuclear factor kappaB is involved in mediating heme-induced TF expression in endothelial cells.

CONCLUSIONS

Our results demonstrate that heme induces TF expression by directly activating endothelial cells, and that heme-induced endothelial TF expression may provide a pathophysiologic link between the intravascular hemolytic milieu and the hemostatic perturbations previously noted in patients with hemolytic anemia including sickle cell disease.

Efficacy and toxicity of a CCNU-containing high-dose chemotherapy regimen followed by autologous hematopoietic cell transplantation in relapsed or refractory Hodgkin's disease

High-dose CBV (cyclophosphamide, carmustine, and etoposide) in combination with autologous HCT achieves survival rates of approximately 50% at 5 years in recurrent or refractory Hodgkin's disease (HD). However, carmustine (BCNU) dose-dependent pulmonary toxicity occurs in 20% to 30% of patients. A decreased incidence of interstitial pneumonitis as well as a possible benefit in efficacy has been reported with lomustine (CCNU) compared to BCNU in the standard dose setting. In a dose-escalation study, we substituted CCNU for BCNU in the CBV regimen for 16 patients with HD (n = 12) or non-Hodgkin's lymphoma (n = 4). Based on the promising results, an additional 47 consecutive patients with HD were treated with the following regimen: CCNU (15 mg/kg) orally on day -6, etoposide (60 mg/kg) intravenously on day -4, and cyclophosphamide (100 mg/kg) intravenously on day -2. Peripheral blood progenitor cells and/or bone marrow were infused on day 0. With a median follow-up for the surviving patients of 3.2 years (range, 0.8-9.9 years), the 3-year overall survival rate was 57% (CI, +/-15%), event-free survival was 52% (CI, +/-14%), and freedom from progression was 68% (CI, +/-14%). There were 21 deaths, 10 due to HD. Six patients died due to respiratory failure. Interstitial pneumonitis occurred in 63% of patients and could not be correlated with prior chest radiotherapy. This regimen demonstrated survival rates similar to those of historical studies that used the CBV regimen. However, the incidence of interstitial pneumonitis was in excess of expected.

Thrombophilia in sickle cell disease: the red cell connection

Complex pertubations of hemostasis occur in sickle cell disease (SCD). Although the procoagulant property of sickle erythrocytes in vitro is tied to exposure of phosphatidylserine (PS), no study has directly linked this PS positivity to in vivo thrombin generation. This study was designed to determine if thrombin generation in SCD correlates with erythrocyte PS, or whether platelets play a significant role. PS was quantified on erythrocytes and platelets from 40 patients with SCD (SS genotype = 25; SC genotype = 15) and 11 controls. Markers of thrombin generation (prothrombin fragment F1.2; thrombin-antithrombin or TAT complexes) and fibrin dissolution (D-dimer; plasmin-antiplasmin or PAP complexes) were also evaluated. Thrombin generation and activation of fibrinolysis occurred with elevations in F1.2, TAT, and D-dimer. Although numbers of both PS-positive erythrocytes and platelets were elevated, there was no correlation between PS-positive platelets and any hemostatic markers. In contrast, correlations were noted between PS-positive erythrocytes and F1.2 (P <.0002), D-dimer (P <.000002), and PAP (P <.01). Correlations between F1.2 and D-dimer (P <.0001) demonstrated that fibrinolysis was secondary to thrombin generation. In patients with the SC genotype, abnormalities in coagulation, although present, were of a lesser magnitude than in SS disease. This study suggests that the sickle erythrocyte is the cell responsible for the thrombophilic state in SCD because associations between erythrocyte PS and thrombin generation were observed. No such relationship with platelet PS was noted. The use of erythrocyte PS as a surrogate marker in trials testing new therapeutic modalities may provide insights into the vascular complications of SCD.

Total knee arthroplasty in patients with isolated patellofemoral arthritis

The current study evaluated the results of total knee arthroplasty for the treatment of isolated patellofemoral degenerative arthritis. Between 1980 and 1997, 31 total knee arthroplasties were done in 24 patients with advanced, isolated patellofemoral arthritis. The average followup was 5.2 years (range, 2-12 years). There was a significant improvement in the mean preoperative Knee Society pain and function scores. Twenty-one knees required a lateral retinacular release and three knees required additional formal proximal realignment at the time of the total knee arthroplasty. There were three reoperations in this series including, manipulation for poor motion in one patient; revision of a loose patellar component in one patient; and extensor mechanism realignment in the third patient. At midterm followup, total knee arthroplasty proved to be reliable and durable in alleviating pain and improving function in this group of patients with isolated, advanced patellofemoral arthritis. Surgeons should be made aware, however, that resurfacing of the patella and balancing the extensor mechanism for patients with isolated patellofemoral arthritis can be demanding technically as evidenced by the high rate of asymmetrically resurfaced patellas, the high rate of lateral retinacular release, and formal realignment procedures.

Neurophysiologic influences on hamstring flexibility: a pilot study

OBJECTIVE

To examine the potential contribution of neurologic influences on hamstring length during passive range of motion.

DESIGN

Prospective study.

SETTINGS

Academic sports medicine center.

PATIENTS

15 subjects undergoing arthroscopic surgery for unilateral knee injuries without previous injury to the contralateral knee.

INTERVENTIONS

Subjects received: 1) spinal anesthesia with bupivacaine, 2) epidural anesthesia with lidocaine, 3) general anesthesia, or 4) femoral nerve block of injured leg only.

MAIN OUTCOME MEASURES

Noninjured leg popliteal angle preoperatively, intraoperatively under anesthesia, and postoperatively after recovery from anesthesia.

RESULTS

The overall mean popliteal angle was 132.5 +/- 3.1 degrees preoperatively, 134.31 +/- 11.6 degrees intraoperatively, and 130.7 +/- 10.2 degrees postoperatively. Overall, the intraoperative angle was significantly greater than the postoperative angle (p = 0.02). The mean change in popliteal angle was 8.1 +/- 2.2 degrees (Group 1), -0.4 +/- 1.9 degrees (Group 2), 0.9 +/- 1.4 degrees (Group 3), and -2.4 +/- 3.8 degrees (Group 4). There was no significant change in pre- to postoperative popliteal angle in relation to postoperative pain. Females had a greater mean popliteal angle (139.84 degrees ) compared with males (128.84 degrees ) (p = 0.04).

CLINICAL RELEVANCE

Understanding the neuromuscular influences on muscle flexibility will assist in the development of new rehabilitative and injury preventative techniques.

CONCLUSION

The present pilot study implicates neural contributions to muscle flexibility. Further studies are needed to delineate the relative contributions of neural and muscular components and to facilitate new techniques in the rehabilitation and prevention of injury.

Fetal hemoglobin in sickle cell anemia: relationship to erythrocyte adhesion markers and adhesion

To assess whether fetal hemoglobin (HbF) modulates the adhesion of sickle erythrocytes to endothelium, children with homozygous sickle cell anemia (SS disease) were studied, using this physiologically crucial period to evaluate the relationships between HbF and the major erythrocyte adhesion markers. The mean level of CD36(+) erythrocytes was 2.59% +/- 2.15% (+/- SD, n = 40) with an inverse relationship between CD36 positivity and F cells (R = -0.76, P < .000 00 002). In univariate analyses, significant correlations with various hematologic parameters and age were noted. Multiple regression analyses, however, revealed a relationship solely with F cells. Minimal levels of very late activation antigen-4(+) (VLA4(+)) erythrocytes (0.31% +/- 0.45%, n = 40) with relationships similar to those noted for CD36(+) cells were also observed. The subpopulation of strongly adhesive stress reticulocytes was further assessed, using CD71 as their marker. The mean level of CD71(+) erythrocytes was 5.81% +/- 4.21%, with statistical correlates in univariate and multivariate analyses similar to those discussed above. When adhesion ratios were evaluated, inverse correlations were noted between basal and plasma-induced adhesion and F-cell numbers (R = -0.54, P < .0005; R = -0.53, P < .0006, n = 39). In addition, in analyses where basal or plasma-induced adhesion was the dependent variable and the independent variables included F cells and the various adhesion-related parameters, significant relationships solely with F cells were noted. The results demonstrate that SS patients with higher levels of F cells have concomitant decreases in the numbers of CD36(+), VLA4(+), and CD71(+) erythrocytes and that these findings translate into less adherent erythrocytes. These findings extend knowledge regarding the protective effects of HbF in the pathophysiology of sickle cell disease.

Acute chest syndrome of sickle cell disease: new light on an old problem

The pulmonary findings of acute chest syndrome of sickle cell disease have been well characterized in numerous studies. Whereas a third of patients have a documented infection associated with this syndrome, and fat embolism from necrotic marrow is the etiologic factor in another approximately 10%, no cause is discovered in the majority of patients. In most patients, however, the underlying pathophysiology is the presence of a hypoxia-driven, adhesion-related occlusive event in the pulmonary microcirculation. This may be accompanied by a decrease in the levels of normal cytoprotective and anti-adhesive mediators such as nitric oxide. In the patient with sickle cell disease, the lung is also a uniquely vulnerable target organ because its vasculature constricts with hypoxia in contrast to other vascular beds. This review will establish the links between known etiologic agents and the pathophysiology of this syndrome. An additional section of this review will deal with experimental therapies. The use of inhaled nitric oxide will be explored in depth because advances in this area are current and uniquely relevant to acute chest syndrome.

Hemostatic alterations in sickle cell disease: relationships to disease pathophysiology

The protean manifestations of sickle cell disease (SCD), especially, microvessel involvement in the vaso-occlusive process, is classically ascribed to the phenomena of erythrocyte sickling and enhanced red cell-endothelial adherence. Pertubations in various hemostatic systems occurs in SCD, both in steady state and during vaso-occlusion, with the intravascular generation of thrombin. The etiology(s) of thrombin generation in SCD will be described. Whether the activation of the cellular and plasmatic phases of hemostasis is causative or occurs as a result of vascular injury will be discussed.

Treatment of periprosthetic tibial fractures

Periprosthetic fractures of the tibia are less commonly encountered and have received less attention than periprosthetic fractures of the patella and distal femur. In contrast with distal femoral fractures, tibial fractures frequently are encountered with loose implants and treatment often requires simultaneous revision knee surgery to address the loose prosthesis, the fracture, and any associated bone deficiencies. In some instances, fractures associated with well-fixed and satisfactorily positioned knee components may be treated by traditional methods of operative or nonoperative fracture management. A classification system, which accounts for the anatomic location of the fracture, the status of prosthesis fixation, and timing of the fracture is helpful in description of the various fracture patterns and direction of the appropriate treatment approach.

Fetal hemoglobin in sickle cell disease: relationship to erythrocyte phosphatidylserine exposure and coagulation activation

In sickle cell disease (SCD), loss of erythrocyte membrane phospholipid asymmetry occurs with the exposure of phosphatidylserine (PS), which provides a docking site for coagulation proteins. In vivo sickling/desickling, with resulting red cell membrane changes and microvesicle formation, appears to be one of the factors responsible for PS exposure. We evaluated children with SCD homozygous for sickle hemoglobin (SS disease) and controls (n = 65) and demonstrate that high levels of fetal hemoglobin (assessed as F cells) are associated with decreased microvesicle formation, PS exposure, and thrombin generation. F cells correlated inversely with both microvesicles and PS positivity (P <.000001) in SS disease. Multiple regression analyses using various hematologic parameters as independent variables, and either microvesicles or PS positivity as the dependent variable, showed a strong relationship only with F cells. Additionally, plasma prothrombin fragment F1.2 levels (a marker for thrombin generation) correlated with both PS positivity (P <.001) and F cells (P <.01). An F-cell level of approximately 70% was associated with normal levels of prothrombin fragment F1.2 and with microvesicle formation indistinguishable from control values. We suggest that the use of such surrogate biologic markers in conjunction with F-cell numbers may provide valuable insights into the biology and consequences of in vivo sickling.

Biomechanical evaluation of a proximal tibial opening-wedge osteotomy plate

This biomechanical study evaluated the static response of a new opening-wedge osteotomy plate to compression and torsion loads in a human cadaver model. This plate incorporates a metal block that distracts the medial tibial cortices to ensure precise correction and prevent bone collapse. The 15-mm plate was inserted into 23 fresh cadaver specimens using a standard surgical technique. Axial loading of 13 specimens (compression) and external rotation loading of 10 specimens (torsion) was performed using a servohydraulic-testing machine. Compression loading resulted in failure at a mean of 1810 N due to bone collapse, fracture, or translation. Torsional loading resulted in failure at a mean of 10 Nm due to fracture of the lateral tibial cortex in all specimens. The ratio of the experimental failure load to the calculated estimate of the knee joint forces during gait were 1.07 in axial compression and 0.925 in torsion. This opening-wedge osteotomy plate construct appears marginally strong enough to withstand the estimated axial load on the proximal tibia during gait. Estimated torsional load on the knee during level walking slightly exceeds the failure load prior to osteotomy healing. This information can be used to guide further experimental protocols for static and dynamic testing of this device to determine the appropriate rehabilitation guidelines following opening-wedge proximal tibial osteotomy.

Sickle cell acute chest syndrome: pathogenesis and rationale for treatment

Acute chest syndrome (ACS) is a leading cause of death in sickle cell disease (SCD). Our previous work showed that hypoxia enhances the ability of sickle erythrocytes to adhere to human microvessel endothelium via interaction between very late activation antigen-4 (VLA4) expressed on sickle erythrocytes and the endothelial adhesion molecule vascular cell adhesion molecule-1 (VCAM-1). Additionally, hypoxia has been shown to decrease the production of nitric oxide (NO) which inhibits VCAM-1 upregulation. Based on these observations, we hypothesize that during ACS, the rapidly progressive clinical course that can occur is caused by initial hypoxia-induced pulmonary endothelial VCAM-1 upregulation that is not counterbalanced by production of cytoprotective mediators, including NO, resulting in intrapulmonary adhesion. We assessed plasma NO metabolites and soluble VCAM-1 in 36 patients with SCD and 23 age-matched controls. Patients with SCD were evaluated at baseline (n = 36), in vaso-occlusive crisis (VOC; n = 12), and during ACS (n = 7). We observed marked upregulation of VCAM-1 during ACS (1,290 +/- 451 ng per mL; mean +/- 1 SD) with values significantly higher than controls (P <.0001) or patients either in steady state or VOC (P <. 01). NO metabolites were concomitantly decreased during ACS (9.2 +/- 1.5 nmol/mL) with values lower than controls (22.2 +/- 5.5), patients during steady state (21.4 +/- 5.5), or VOC (14.2 +/- 1.2) (P <.0001). Additionally, the ratio of soluble VCAM-1 to NO metabolites during ACS (132.9 +/- 46.5) was significantly higher when compared with controls (P <.0001) or patients either in steady state or VOC (P <.0001). Although hypoxia enhanced in vitro sickle erythrocyte-pulmonary microvessel adhesion, NO donors inhibited this process with concomitant inhibition of VCAM-1. We suggest that in ACS there is pathologic over expression of endothelial VCAM-1. Our investigations also provide a rationale for the therapeutic use in ACS of cytoprotective modulators including NO and dexamethasone, which potentially exert their efficacy by an inhibitory effect on VCAM-1 and concomitant inhibition of sickle erythrocyte-endothelial adhesion.

A commonsense approach to shoulder problems

Shoulder pain is a common entity in a primary care physician's practice. The unique anatomy of the shoulder allows for almost unrestrained motion in all planes. A thorough history and physical examination are important to ensure efficient patient evaluation. Further assessment may include radiographic and diagnostic laboratory tests. This article presents an organized approach to the anatomy, physiology, and pathology of common shoulder disorders for the primary care physician. The distinction between disorders that are intrinsic or extrinsic to the shoulder joint is discussed. Treatment and the need for appropriate referral are described.

Total knee arthroplasty: periprosthetic tibial fractures

A classification for periprosthetic tibial fractures is presented. It is based on the anatomic location of the fracture in reference to the tibial component; whether the fracture occurred during surgery or in the postoperative period; and whether the prosthesis is radiographically well-fixed or loose. A treatment algorithm is proposed for each fracture type.

A longitudinal examination of athletes' emotional and cognitive responses to anterior cruciate ligament injury

OBJECTIVE

To determine the emotional and cognitive impact of injury and surgery on physical recovery in injured athletes.

DESIGN

A prospective longitudinal study comparing the psychosocial and physical recovery of competitive and recreational athletes.

SETTING

Tertiary-care sports medicine center.

PARTICIPANTS

Twenty-seven athletes (15 men and 12 women) who required anterior cruciate ligament (ACL) reconstruction surgery.

INTERVENTIONS

A repeated-measures design used to compare the psychosocial and physical changes for 6 months after ACL surgery.

MAIN OUTCOME MEASURES

Emotional (mood) and cognitive (coping) functions and physical recovery (range of motion, physician-rated level of recovery, and physician permission to return to sport).

RESULTS

There was a significant time-effect difference in mood, with a greater mood disturbance and recovery rate for competitive athletes than recreational athletes. Differences in mood and pain coping were significant at 2 weeks and 2 months after surgery.

CONCLUSION

Athletes experience significant mood changes throughout rehabilitation, which may hinder rehabilitation early in the process. Longer-term rehabilitation was not impacted by mood or pain coping. Future studies might focus on examining the process over a longer time period (1-2 years after surgery). Physicians should be aware of these findings and appropriately counsel and motivate athletes toward more favorable positive psychological and physical outcomes.

Flexion instability after primary posterior cruciate retaining total knee arthroplasty

Between 1990 and 1995, 25 painful primary posterior cruciate ligament retaining total knee arthroplasties were revised for flexion instability. These patients shared typical clinical presentations that included a sense of instability without frank giving way, recurrent knee joint effusion, soft tissue tenderness involving the pes anserine tendons and the retinacular tissue, posterior instability of 2+ or 3+ with a posterior drawer or a posterior sag sign at 90 degrees flexion, and above average motion of their total knee arthroplasty. The primary total knee arthroplasty was performed for osteoarthritis in 23 patients and rheumatoid arthritis in two patients. There were 13 male and 12 female patients and their mean age was 65 years (range, 35-77 years). Before the revision operation, Knee Society knee scores averaged 45 points (range, 17-68 points) and function scores averaged 42 points (range, 0-60 points). Twenty-two of the knee replacements were revised to posterior stabilized implants and three underwent tibial polyethylene liner exchange only. Nineteen of the 22 knee replacements revised to a posterior stabilized implant were improved markedly after the revision surgery. Only one of three knee replacements that underwent tibial polyethylene exchange was improved. After the revision for flexion instability, Knee Society knee scores averaged 90 points (range, 82-99 points) and function scores averaged 75 points (range, 45-100 points) for the 20 knees with a successful outcome. This study suggests that flexion instability can be a cause of persistent pain and functional impairment after posterior cruciate ligament retaining total knee arthroplasty. A revision operation that focuses on balancing the flexion and extension spaces, in conjunction with a posterior stabilized knee implant, seems to be a reliable treatment for symptomatic flexion instability after posterior cruciate retaining total knee arthroplasty.

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.

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.

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.

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.