D. B. Clement

A retrospective case-control analysis of 2002 running injuries

Objective: To provide an extensive and up to date database for specific running related injuries, across the sexes, as seen at a primary care sports medicine facility, and to assess the relative risk for individual injuries based on investigation of selected risk factors. Methods: Patient data were recorded by doctors at the Allan McGavin Sports Medicine Centre over a two year period. They included assessment of anthropometric, training, and biomechanical information. A model was constructed (with odds ratios and their 95% confidence intervals) of possible contributing factors using a dependent variable of runners with a specific injury and comparing them with a control group of runners who experienced a different injury. Variables included in the model were: height, weight, body mass index, age, activity history, weekly activity, history of injury, and calibre of runner. Results: Most of the study group were women (54%). Some injuries occurred with a significantly higher frequency in one sex. Being less than 34 years old was reported as a risk factor across the sexes for patellofemoral pain syndrome, and in men for iliotibial band friction syndrome, patellar tendinopathy, and tibial stress syndrome. Being active for less than 8.5 years was positively associated with injury in both sexes for tibial stress syndrome; and women with a body mass index less than 21 kg/m2 were at a significantly higher risk for tibial stress fractures and spinal injuries. Patellofemoral pain syndrome was the most common injury, followed by iliotibial band friction syndrome, plantar fasciitis, meniscal injuries of the knee, and tibial stress syndrome. Conclusions: Although various risk factors were shown to be positively associated with a risk for, or protection from, specific injuries, future research should include a non-injured control group and a more precise measure of weekly running distance and running experience to validate these results.

Stress fractures in athletes: A study of 320 cases

We analyzed cases of 320 athletes with bone scan- positive stress fractures (M = 145, F = 175) seen over 3.5 years and assessed the results of conservative management. The most common bone injured was the tibia (49.1 %), followed by the tarsals (25.3%), metatar sals (8.8%), femur (7.2%), fibula (6.6%), pelvis (1.6%), sesamoids (0.9%), and spine (0.6%). Stress fractures were bilateral in 16.6% of cases. A significant age difference among the sites was found, with femoral and tarsal stress fractures occurring in the oldest, and fibular and tibial stress fractures in the youngest. Run ning was the most common sport at the time of injury but there was no significant difference in weekly running mileage and affected sites. A history of trauma was significantly more common in the tarsal bones. The average time to diagnosis was 13.4 weeks (range, 1 to 78) and the average time to recovery was 12.8 weeks (range, 2 to 96). Tarsal stress fractures took the longest time to diagnose and recover. Varus alignment was found frequently, but there was no significant difference among the fracture sites, and varus alignment did not affect time to diagnosis or recovery. Radiographs were taken in 43.4% of cases at the time of presentation but were abnormal in only 9.8%. A group of bone scan- positive stress fractures of the tibia, fibula, and meta tarsals (N = 206) was compared to a group of clinically diagnosed stress fractures of the same bone groups (N = 180), and no significant differences were found. Patterns of stress fractures in athletes are different from those found in military recruits. Using bone scan for diagnosis indicates that tarsal stress fractures are much more common than previously realized. Time to diagnosis and recovery is site-dependent. Technetium99 bone scan is the single most useful diagnostic aid. Conservative treatment of stress fractures in athletes is satisfactory in the majority of cases.

A Survey of Overuse Running Injuries

In brief: This retrospective survey of the clinical records of 1,650 patients seen from 1978 to 1980 identified 1,819 injuries. Almost 60% of the patients were men, but women under age 30 had the greatest risk of overuse running injuries. The knee was the most commonly injured site, and patellofemoral pain syndrome was the most common injury. Most patients had moderate to severe degrees of varus alignment and subsequent overpronation. Because certain injuries were more frequent in one sex or the other, the authors say future studies should differentiate injuries by sex.

Achilles tendinitis and peritendinitis: Etiology and treatment

One hundred nine runners were treated conservatively without immobilization for overuse injury to the Achilles tendon. Treatment strategies were directed toward re habilitation of the gastrocnemius/soleus muscle-tendon unit, control of inflammation and pain, and control of biomechanical parameters. One fair, 12 good, and 73 excellent results were reported, with a mean recovery time of 5 week.Followup was incomplete in 23 cases. The three most prevalent etiological factors were overtraining (82 cases), functional overpronation (61 cases), and gastrocnemius/soleus insufficiency (41 cases). The authors speculate that runners are susceptible to Achilles tendinitis with peritendinitis due to micro- trauma produced by the eccentric loading of fatigued muscle, excess pronation producing whipping action of the Achilles tendon, and/or vascular blanching of the Achilles tendon produced by conflicting internal and external rotatory forces imparted to the tibia by simul taneous pronation and knee extension. Virtually all cases of Achilles tendon injury appear to result from structural or dynamic disturbances in normal lower leg mechanics and require active treatment regimens which attempt to establish normal function to prevent recur rence.

A prospective study of running injuries: the Vancouver Sun Run “In Training” clinics

Objectives: Seventeen running training clinics were investigated to determine the number of injuries that occur in a running programme designed to minimise the injury rate for athletes training for a 10 km race. The relative contributions of factors associated with injury were also reported. Methods: A total of 844 primarily recreational runners were surveyed in three trials on the 4th, 8th, and 12th week of the 13 week programme of the “In Training” running clinics. Participants were classified as injured if they experienced at least a grade 1 injury—that is, pain only after running. Logistic regression modelling and odds ratio calculation were performed for each sex using the following predictor variables: age, body mass index (BMI), previous aerobic activity, running frequency, predominant running surface, arch height, running shoe age, and concurrent cross training. Results: Age played an important part in injury in women: being over 50 years old was a risk factor for overall injury, and being less than 31 years was protective against new injury. Running only one day a week showed a non-significant trend for injury risk in men and was a significant risk factor in women and overall injury. A BMI of > 26 kg/m2 was reported as protective for men. Running shoe age also significantly contributed to the injury model. Half of the participants who reported an injury had had a previous injury; 42% of these reported that they were not completely rehabilitated on starting the 13 week training programme. An injury rate of 29.5% was recorded across all training clinics surveyed. The knee was the most commonly injured site. Conclusions: Although age, BMI, running frequency (days a week), and running shoe age were associated with injury, these results do not take into account an adequate measure of exposure time to injury, running experience, or previous injury and should thus be viewed accordingly. In addition, the reason for the discrepancy in injury rate between these 17 clinics requires further study.

Running Shoes, Orthotics, and Injuries

SummaryRunning is the most visible expression of the continued interest in regular physical activities. Unfortunately injuries are common, primarily due to overuse, and a number of aetiological factors have been recognised. Of these, training errors can be responsible for up to 60% of injuries. The training surface, a lack of flexibility and strength, the stage of growth and development, poor footwear and abnormal biomechanical features have all been implicated in the development of running injuries. A thorough understanding of the biomechanics of running is a necessary prerequisite for individuals who treat or advise runners.Clinically, the configuration of the longitudinal arch is a valuable method of classifying feet and has direct implications on the development and management of running problems. The runner with excessively pronated feet has features which predispose him/her to injuries that most frequently occur at the medial aspect of the lower extremity: tibial stress syndrome; patellofemoral pain syndrome; and posterior tibialis tendinitis. These problems occur because of excessive motion at the subtalar joint and control of this movement can be made through the selection of appropriate footwear, plus orthotic foot control. The runner with cavusfeet often has a rigid foot and concomitant problems of decreased ability to absorb the force of ground contact. These athletes have unique injuries found most commonly on the lateral aspect of the lower extremity; iliotibial band friction syndrome; peroneus tendinitis; stress fractures; trochanteric bursitis; and plantar fasciitis. Appropriate footwear advice and the use of energy-absorbing materials to help dissipate shock will benefit these individuals. Running shoes for the pronated runner should control the excessive motion. The shoes should be board-lasted, straight-lasted, have a stable heel counter, extra medial support, and a wider flare than the shoes for the cavusfoot. For these athletes a slip-lasted, curve-lasted shoe with softer ethylene vinyl acetate (EVA) and a narrow flare is appropriate. Orthotic devices are useful in selected runners with demonstrated biomechanical abnormalities that contribute to the injury. Soft orthotics made of a commercial insole laminated with EVA are comfortable, easily adjusted, inexpensive, and more forgiving than the semirigid orthotics which are useful in cases where the soft orthotic does not provide adequate foot control.A review of injury data shows an alarming rise in the incidence of knee pain in runners — from 18% to 50% of injuries in 13 years. Errors in training judgement, with excessive loading, particularly in runners with compromised biomechanical features, represent the primary aetiological factors. These errors cannot be accommodated by running shoe design. Similarly, orthotic devices alone will not control the injury pattern of most runners. Although footwear and biomechanical control may represent a significant therapeutic intervention in some individuals, they must remain part of a comprehensive rehabilitation programme that considers the other aetiological factors that contribute to running injuries.

Iron status in athletes. An update

SummaryAs more studies are done on the iron status of athletes, the significance of apparent iron deficiency remains controversial. Do observed changes in iron status in athletes indicate an actual iron deficiency or a physiological response to exercise? Iron replacement would clearly be indicated if an iron deficiency was present but would not be necessary or effective if the observed changes were simply a physiological response. There is agreement that serum ferritin and haemoglobin decrease with some exercise conditions and that some indicators of haemolysis, such as serum haptoglobin and bilirubin, change in response to exercise. Expansion of plasma volume and the shift of iron storage from bone marrow to the liver could support the claim that the apparent reduced iron status parameters occurring with exercise are misleading. Countering this concept are studies in athletes which demonstrate dietary iron intake deficiencies and blood loss in the gastrointestinal and urinary tract. Iron deficiency is common in the general population, particularly in women. Therefore, continued monitoring of iron status in athletes appears justified in the face of present knowledge. Replacement therapy, when iron deficiency is apparent, is recommended.

Iron Status and Sports Performance

SummaryIn recent years, epidemiological studies of the iron status of athletes involved in heavy training have suggested that these athletes may be prone to iron deficiency. Several investigators have observed a high prevalence of iron deficiency among athletes, particularly endurance runners, based on serum ferritin levels, which accurately reflect the size of the body’s iron stores. Furthermore, earlier reports on iron status in athletes frequently noted low haemoglobin values in those involved in heavy endurance training. In addition to iron deficiency anaemia, a condition known as ‘sports anaemia’ has also been described, in which the athlete experiences an increased destruction of erythrocytes and a drop in haemoglobin as a result of an acute stress response to exercise.Whether iron deficiency in athletes is due to an inadequate dietary intake of iron, an exercise effect on iron metabolism, or a combination of both, has yet to be determined. Certainly, it is questionable whether adequate iron is consumed in a typical Western diet, particularly by females, who already have an increased requirement related to menstruation. In addition, recent evidence strongly suggests that exercise may impose a significant iron ’cost’ on the athlete. This additional iron cost may be the result of the increased destruction of red blood cells, increased elimination of iron, or possibly an impaired iron absorption.Regardless of the cause, however, iron deficiency, with or without anaemia, is an undesirable condition for athletes. An essential constituent of haemoglobin, myoglobin and several iron-containing respiratory enzymes, iron plays a vital role in energy production. With only minor decrements in haemoglobin, anaemic subjects have been shown to have impaired physical performance. More recently, iron deficiency without anaemia has been examined and this condition has also been shown to reduce physical work capacity and lead to excess lactate production.Therefore, regular monitoring of the iron status of athletes is recommended to ensure optimal performance ability. This should include routine examination of serum ferritin and haemoglobin levels in addition to periodical dietary analyses of the athlete’s nutritional intake. If an iron-deficient condition is detected, prompt intervention involving nutritional counselling and/or iron supplementation is necessary.

Achilles tendon disorders in runners--a review.

The Achilles tendon and the classification, etiology, diagnosis, treatment, and management of Achilles tendon disorders in runners are reviewed. Due to the presence of a paratenon sheath, the classification of Achilles tendon disease should be revised. Several etiological mechanisms have been proposed in Achilles tendon disease. The authors recognize: faulty foot biomechanics; poor lower leg flexibility; poorly designed athletic footwear; training surfaces; training intensity; overuse through excessive mileage; inactivity; local steroid injections; rheumatic conditions; and indirect violence. An accurate, thorough differential diagnosis is essential when the athlete presents with an Achilles tendon disorder. Except in total rupture and in extensive partial rupture, the authors do not recommend cast immobilization in the treatment of Achilles tendon disease. When the athlete presents with total rupture of the Achilles tendon, the authors believe that surgical repair is the treatment method of choice. Rehabilitation programs to follow successful treatment of Achilles tendon disease are also presented.

Scintigraphic Uptake of 99mTc at Non-Painful Sites in Athletes with Stress Fractures

SummaryStress fractures are commonly found in athletes attending sports medicine clinics for diagnosis of lower limb pain. Plain radiographs are less reliable than the 99mTc bone scan for diagnosing stress fractures because of their low sensitivity. While the heightened sensitivity of the bone scan is advantageous as a diagnostic aid, the uptake of99mTc at non-painful sites occurs frequently in the athlete. Although the clinical significance has not been determined, asymptomatic uptake may indicate bone remodelling as part of a continuum of adaptation to physical stress. It is not known whether athletes who have uptake of99mTc in asymptomatic areas represent a separate population from those who do not. This study retrospectively reviewed the medical charts and bone scan reports of 320 athletes diagnosed as having stress fractures, to determine the frequency of asymptomatic focal uptake at sites other than the site of pain. This group was compared with the group who had no asymptomatic uptake on a number of demographic variables and physical findings. Asymptomatic focal uptake was found in 37.5% of athletes with the average number of sites being 1.8 per person. No significant differences between groups with focal asymptomatic uptake and groups with no asymptomatic uptake were found when compared4 for age, height, weight, mileage in runners, times to diagnosis and recovery, frequency of tenderness, swelling, trauma history, varus alignment, and x-ray abnormalities. It is concluded that asymptomatic uptake of99mTc occurs frequently in athletes with stress fractures and there are no significant clinical differences between the group with asymptomatic uptake and the group without. It is suggested that symptomatic uptake of99mTc represents the remodelling response of bone to physical stress.