Intensive training in young athletes. The orthopaedic surgeon's viewpoint

A young athlete's musculoskeletal system is unique, in that it is not only growing, but is giving support to the growing soft tissues as well. With this in mind, it is easily understood that the fastest growing areas of children skeletal system are at greater risk of injury. No controlled longitudinal studies have yet been performed about the long term effects of injuries occurring in intensively trained young athletes. During the growth spurt, a dissociation between bone matrix formation and bone mineralisation occurs, thus leaving the child with the risks of chronic moderate-to-high overloading, sudden great overload, and diminished bone strength. This may account for both acute and overuse bone injuries in this age group. Epiphyseal plate injuries can have disastrous consequences. About 10% of all skeletal trauma in children involves the epiphysis, but few long-lasting effects have been reported. It is not clear whether intensively trained young athletes are at greater risk of injury than children engaged in free-play activities. It is worrying, though, that about 20% of injuries in sports children require internal fixation. Few studies have addressed injuries to tendons, ligaments and the enthesis in young athletes. It seems that tendon injuries are mild, not requiring surgery, and with a low recurrence rate, but no prospective studies have been performed. Avulsion of the ligamentous insertion occurs more frequently than ligament ruptures in this age group, even though they seem on the increase. Osteochondritis dissecans affects weightbearing joints such as the hip, the knee and the ankle, but elbow lesions in gymnasts and throwers are also relatively frequent. If it occurs before epiphyseal fusion, long term effects are scarce. The centre of growth or ossification where a major tendon is attached may undergo chronic inflammation and avulsion of cartilage and bone, due to the stresses transmitted to it. Typical areas are the inferior pole of the patella, the tibial tubercle and the calcaneal apophysis. Sports activity contributes to the disease by excessive traction at the tendinous and fascial insertion, or as a result of direct pressure. The lumbar spine is subjected to enormous forces in some sports. The true incidence of lumbar disc lesions in sporting children is not known, but it seems that acute trauma may play a major role. With the increase of the intensity and duration of training programmes, degenerative changes may play an adjuvant role.(ABSTRACT TRUNCATED AT 400 WORDS)     

Ultrasound for diagnosis of apophyseal injuries

Avulsion injuries of the apophysis is a problem in young athletes. A correct diagnosis is necessary for establishing the appropriate treatment and the rehabilitation program. However, it is often difficult to distinguish between a simple muscle strain and an avulsion fracture. The X-ray examination is helpful only when an ossification center of the apophysis exists. Ultrasonography is considered the suitable diagnostic tool for these cases. From June 1988 to June 1993, 243 young athletes were seen with an anamnestic and clinically suspected apophyseal injury of the lower extremity. In all cases X-ray examination and ultrasound examination were performed. In 80 cases the diagnosis was confirmed by X-ray examination and in 97 by ultrasonography. Four criteria were defined for the sonographic examination: (a) a hypoechogenic zone, (b) increased distance to the apophysis, (c) dislocation of the apophysis, and (d) mobility of the apophysis on dynamic examination. These criteria are correlated to (a) edema, (b) lysis, (c) avulsion, and (d) unstable avulsion of the apophysis. Ultrasonography is a proven technique for the detection of apophyseal injuries. In comparison to X-ray examination, it has the advantages of no radiation exposure, early detection even without ossification center, and dynamic examination.     

Patellar tendinosis as an adaptive process: a new hypothesis

Background: Patellar tendinosis (PT), or "jumper's knee" is a common condition in athletes participating in jumping sports, and is characterised by proximal patellar tendon pain and focal tenderness to palpation. Hypoechoic lesions observed in the proximal patellar tendon associated with the tendinosis are typically described as being a result of degenerative change or "failed healing". We propose a new model for the development of the hypoechoic lesion observed in PT, in which the aetiology is an adaptive response to differential forces within the tendon.     

Etiology and pathophysiology of chronic tendon disorders in sports

In sports medicine, a chronic overuse injury is defined as a long-standing or recurring orthopedic problem and pain in the musculoskeletal system, which started during exertion due to repetitive tissue microtrauma (1). Repetitive microtrauma, which is basically repeated exposure of the musculoskeletal tissue to low-magnitude forces, results in injury at the microscopic level, and no single acute trauma is normally involved in the pathogenesis of an overuse injury. In chronic tendon disorders, 'overuse'implies that the tendon has been strained repeatedly to 44% strain until unable to endure further tension, whereupon injury occurs (2). The structure of the tendon is disrupted micro- or macroscopically by this repetitivestrain, i.e. collagen fibers begin to slide past one another, causing breakage of their cross-linked structure, and denaturate; inflammation, edema and pain result. Thus, tendinitis, peritendinitis, tenosynovitis, insertion tendinitis, tendinous bursitis or apophysitis is the earliest clinically recognizable manifestation of overuse tendon injury (3).     

Avulsion injuries of the pelvis

Pelvic avulsion injuries occur in both the skeletally immature and adult patient populations. Avulsion injuries are most common in the adolescent age group and usually present as an avulsion of the unfused apophysis at the level of tendon attachment resulting from violent muscular contraction during an athletic endeavor. Acute apophyseal avulsion injuries are usually easily detected and adequately imaged with radiographs, but occasionally advanced imaging such as magnetic resonance imaging or computed tomography is required to detect and fully delineate the extent of injury. Chronic injuries can mimic a more aggressive lesion, but familiarity with the location of various tendon attachment sites on the osseous pelvis can help avoid this pitfall. Traumatic avulsion injuries can also occur in the skeletally mature pelvis; however, in the adult, the presence of a pelvic avulsion fracture in the absence of trauma should be considered a pathological lesion until proven otherwise. This article discusses the clinical and imaging findings of apophyseal avulsion injuries in the adolescent athlete, followed by a discussion of specific pelvis avulsion injuries that occur in the adult population.     

The anatomy of the proximal tibia in pediatric and adolescent patients: implications for ACL reconstruction and prevention of physeal arrest

Although the treatment of anterior cruciate ligament (ACL) tears in skeletally immature patients is still controversial, several studies have advocated ACL reconstruction in selected patients to prevent secondary injury. The proximal tibial physis is a structure at risk during ACL reconstruction in young patients, and physeal growth complications have been reported after surgery in this area. The relationship between the ACL and the proximal tibial physeal/apophyseal regions is poorly understood. This study examined the MRI anatomy of the ACL and the proximal tibia apophysis and epiphysis. MRIs of 59 skeletally immature knees were reviewed (Average age = 12.75 years, range 6–15) to define the anatomy of the epiphyseal and apophyseal regions. Measurements were recorded in three parasagittal planes: (1) at the lateral border of the patellar tendon, (2) the lateral edge of the ACL insertion, and (3) the medial edge of the ACL insertion. A single three-dimensional (3D) computed tomography (CT) scan was used to evaluate the position of standard drill holes used in ACL reconstruction to assess for potential degree of injury to the epiphyseal and apophyseal growth plates. In the parasagittal planes, the average height of the epiphysis was 19.6, 20.7, and 21.5 mm at the lateral border of the patellar tendon, the lateral border of the ACL, and the medial border of the ACL, respectively. At the level of the same landmarks, the apophysis extended below the physis at an average of 20.2, 16.8, and 7.0 mm, respectively. Expressed as a percentage of epiphysis height this was an average of 104, 82, and 33%, respectively. Examination of 3D CT images revealed that variations in drill hole placement had effects on the volume of injury to the proximal tibial physis and apophysis. Drill holes that started more medial, distal, and with a steeper angle of inclination reduced the amount of physis and apophysis violated when compared with holes placed more lateral, proximal, and with a shallow angle of inclination. The proximal tibial physis and apophysis is vulnerable to injury by drill hole placement during ACL reconstruction in skeletally immature patients. This paper defines the anatomic relationship of the apophyseal and epiphyseal regions of the physis in the proximal tibia. The volume of injury to the physis can be reduced by avoiding tunnel placement that is too lateral or too proximal on the tibia. A better understanding of these relationships may guide the placement of tibial drill holes, which have a lower risk of producing significant physeal damage. The preliminary work on this topic was presented at the 2000 Meeting of the Pediatric Orthopaedic Society of North America, Vancouver, Canada, and the 2001 American Academy of Orthopaedic Surgeons Annual Meeting in San Francisco.     

Functional anatomy of the Achilles tendon

The Achilles tendon is the strongest and thickest tendon in the human body. It is also the commonest tendon to rupture. It begins near the middle of the calf and is the conjoint tendon of the gastrocnemius and soleus muscles. The relative contribution of the two muscles to the tendon varies. Spiralisation of the fibres of the tendon produces an area of concentrated stress and confers a mechanical advantage. The calcaneal insertion is specialised and designed to aid the dissipation of stress from the tendon to the calcaneum. The insertion is crescent shaped and has significant medial and lateral projections. The blood supply of the tendon is from the musculotendinous junction, vessels in surrounding connective tissue and the osteotendinous junction. The vascular territories can be classified simply in three, with the midsection supplied by the peroneal artery, and the proximal and distal sections supplied by the posterior tibial artery. This leaves a relatively hypovascular area in the mid-portion of the tendon where most problems occur. The Achilles tendon derives its innervation from the sural nerve with a smaller supply from the tibial nerve. Tenocytes produce type I collagen and form 90% of the cellular component of the normal tendon. Evidence suggests ruptured or pathological tendon produce more type III collagen, which may affect the tensile strength of the tendon. Direct measurements of forces reveal loading in the Achilles tendon as high as 9 KN during running, which is up to 12.5 times body weight.     

MRI appearance of chronic stress injury of the iliac crest apophysis in adolescent athletes

OBJECTIVE: The objective of our study was to describe the MRI appearance of chronic repetitive stress injury of the iliac crest apophysis in adolescent athletes. CONCLUSION: Increased signal intensity on water-sensitive sequences and mild widening of the physis, often with adjacent bone marrow and muscle edema, are characteristic of chronic stress injury of the iliac apophysis in adolescent athletes who may present with hip, pelvic, or back pain.     

Sonographic evaluation of apophyseal ossification of the iliac crest in forensic age diagnostics in living individuals

Due to the requirement to minimise exposure to radiation, it is desirable to develop non-ionising imaging procedures for the analysis of skeletal maturation for forensic age diagnostics in living individuals. The present pilot study analyses the applicability of ultrasound examinations for the evaluation of apophyseal ossification of the iliac crest. With reference to the sonographic staging of clavicular ossification, the maturation stages of the iliac crest apophysis of 23 male and 16 female subjects, aged 11–20 years, were determined. Ossification stage I occurred in the male subjects at a minimum age of 15.7 years. Ossification stage II was diagnosed in boys at a minimum age of 14.1 years and in girls at a minimum age of 11.7 years. The earliest observation of ossification stage III was at a chronological age of 16.2 years in males and 15.2 years in females. The earliest age of occurrence of ossification stage IV was at least 18.0 years in male test persons and at least 17.1 years in female test persons. The results obtained should be reassessed in a larger number of cases. It is to be expected that sonographic examination of the iliac crest apophysis will become established as a valid and efficient method for forensic age diagnostics in living individuals.     

Belastungsabhängige Prävalenz von Patellasehnen-Tendinopathie und sonographischen Veränderungen junger Nachwuchsathleten

BackgroundPrevalence of Patella tendinopathy (PT) in athletes was shown to be present in up to 45%. However, representative data of PT and morphological tendon alterations in adolescent athletes at the beginning of their systematic training are not known, yet.Material und MethodsA total of 536 adolescent athletes (12.6±1.5 years) out 16 different sports, categorized into 6 types of sports, were included in the study. Tendinopathy was diagnosed in case of pain in history and tendon pain on palpation. Structural tendon irregularities (neovascularization, hypo- und hyperechogenicities) were detected sonographically.ResultsIn 4.5% of the adolescent athletes PT was diagnosed. No statistically significant differences were detected in prevalence of PT between different categories. Sonographically 11.8% of tendons presented neovascularizations, 1.6% hypo- and 0.2% hyperechogenicities. Symptomatic tendons had significantly more neovascularizations and hypoechogenicities.ConclusionsPT is present already at the start of systematic training in adolescent athletes. It correlates with a higher amount of intratendinous structural changes.Level of evidenceII (Cohort study – Cross-sectional survey)     

Etiology and pathophysiology of tendon ruptures in sports

Of all spontaneous tendon ruptures, complete Achilles tendon tears are most closely associated with sports activities (1–3). Schönbauer (3) reported that 75% of all ruptures of the Achilles tendon are related to sports. In Plecko & Passl (2) the number was 60%. In our material of 430 cases, the number of sports-related Achilles ruptures was very similar (62%), while only 2% of ruptures of other tendons were sports-related (P<0.001) (1). Also, the majority of Achilles reruptures occurred in sports. The ruptures occurred most often in soccer (34%), track and field (16%) and basketball (14%). The distribution of Achilles ruptures according to different sports varies considerably from country to country, according to the national sport traditions. For example, in northern and middle Europe, soccer, tennis, track and field, indoor ball games, downhill skiing, and gymnastics are the most common; and in North America, football, basketball, baseball, tennis and downhill skiing dominate the statistics (1, 2, 4). In sports, some Achilles ruptures are not spontaneous or degeneration-induced but may occur as a consequence of the remarkably high forces that are involved in the performance (2). Ruptures in the high jump or triple jump are good examples. In such cases, failure in the neuromuscular protective mechanisms due to fatigue or disturbed co-ordination can frequently be found. The spontaneous complete rupture of the supraspinatus tendon of the rotator cuff does not occur very frequently in sports. Those sports that include high-energy throwing movements, such as American and Finnish baseball, American football, rugby and discus and javelin throwing, may, however, produce this injury. Partial tears and inflammations of the rotator cuff complex are much more frequent in throwing sports. The complete rupture of the proximal long head of the biceps brachii tendon is rare among competitive and recreational athletes. In our material, under 2% of these ruptures were associated with sports activities (5). The rupture (avulsion) of the distal tendon of the biceps muscle is rare. In sports, gymnastics, body building and weight lifting have been said to be able to produce this injury (6). In general, complete ruptures of the quadriceps tendon and the patellar tendon occur most often in older individuals. In our study, the mean age of these patients was 65 years (5). However, these injuries do also occur in younger age groups, especially in athletes. In athletes, the rupture most frequently occurs in high-power sports events, such as high jump, basketball and weight lifting, at the age of 15-30 years. A chronic patellar apicitis (jumper's knee) may predispose rupture of the tendon (7). As is the case with the rotator cuff complex, overuse inflammation and partial tears of the quadriceps and patellar tendons are one of the most characteristic athletic injuries. Complete spontaneous ruptures of other tendons in sports are rare, although the literature does provide case studies from almost every tendon the human body possesses (8–18).     

Evidence of imbalanced adaptation between muscle and tendon in adolescent athletes

Adolescence may be regarded as a critical phase of tissue plasticity in young growing athletes, as the adaptation process of muscle‐tendon unit is affected by both environmental mechanical stimuli and maturation. The present study investigated potential imbalances of knee extensor muscle strength and patellar tendon properties in adolescent compared with middle‐aged athletes featuring long‐term musculotendinous adaptations. Nineteen adolescent elite volleyball athletes [(A), 15.9 ± 0.6 years] and 18 middle‐aged competitively active former elite volleyball athletes [(MA), 46.9 ± 0.6 years] participated in magnetic resonance imaging and ultrasound‐dynamometry sessions to determine quadriceps femoris muscle strength, vastus lateralis morphology and patellar tendon mechanical and morphological properties. There was no significant age effect on the physiological cross‐sectional area of the vastus lateralis and maximum knee extension moment (P > 0.05) during voluntary isometric contractions. However, the patellar tendon cross‐sectional area was significantly smaller (A: 107.4 ± 27.5 mm²; MA: 121.7 ± 39.8 mm²) and the tendon stress during the maximal contractions was significantly higher in adolescent compared with the middle‐aged athletes (A: 50.0 ± 10.1 MPa; MA: 40.0 ± 9.5 MPa). These findings provide evidence of an imbalanced development of muscle strength and tendon mechanical and morphological properties in adolescent athletes, which may have implications for the risk of tendon overuse injuries.     

Biomechanics, load analysis and sports injuries in the lower extremities

The study of sports injuries has grown with the increase in importance of sport as a leisure-time activity. The origin of many sports injuries is assumed to be mechanical, with the forces and/or stresses acting on one element of the human locomotor system exceeding the critical limits. This article presents some biomechanical considerations on the mechanical aspect of the aetiology, reduction and treatment of sport injuries with special emphasis on the lower extremities. Forces acting on the locomotor system have a magnitude, a point of application and a direction. Both magnitude and geometry (point of application and direction) are important in load analysis. However, the geometrical aspect of externally acting forces is an extremely important aspect, especially with respect to reduction of load in practical situations. Load analysis is usually performed with force transducers and optical instruments in order to quantify magnitude and geometry. Two possible approaches to load analysis are discussed. One approach works with the critical limits of biomaterials. This approach shows that the local stresses for cartilage, tendon and bone are in the order of 10 to 20% of the critical limit for normal daily activities, such as walking. The second approach deals with strategies to reduce load, assuming that it is usually too high in sports activities. The nature of playing surfaces and shoes are revealed as important possibilities for load reduction.     

Pellegrini–Stieda disease: a heterogeneous disorder not synonymous with ossification/calcification of the tibial collateral ligament—anatomic and imaging investigation

Objective Ossification/calcification around the medial femoral condyle has been known as Pellegrini–Stieda (PS) disease for almost 100 years. Little attention has been given to magnetic resonance (MR) imaging characteristics. Our purpose is to demonstrate the anatomy in the medial femoral compartment and imaging findings of PS disease, determining the sites and patterns of ossification.Design and patients In a cadaveric study seven specimens were dissected to show the anatomic relations of the tibial collateral ligament (TCL) and the tendon of the ischiocondylar part of the adductor magnus muscle, in the medial femoral epicondyle. In order to determine the nature of ossification/calcification in PS disease, MR imaging and radiographic findings in nine patients were analyzed by two observers with attention to the specific site, shape, and orientation of the ossification and its relationship to the tibial collateral ligament (TCL) and adductor magnus tendon. Available clinical history was recorded. A classification system addressing different sites and patterns of ossification was developed.Results The anatomic study showed that the TCL and the adductor magnus tendon insert at different sites in the medial femoral condyle and there is no continuation; however, some fibers of the posterior bundle of the TCL overlap the anterior aspect of the adductor magnus tendon. The imaging study showed that shape, orientation, and location of the abnormal calcification and ossification were similar on radiographic and MR imaging analysis. Ossification had an inferior orientation in six cases, a superior orientation in two cases, and both in one case. Four patterns of ossification were noted: (I) a beak-like appearance with an inferior orientation and femoral attachment was present in five cases; (II) a drop-like appearance with an inferior orientation, parallel to the femur, was evident in one case; (III) an elongated appearance with a superior orientation, parallel to the femur, was seen in two cases; and (IV) a beak-like appearance with an inferior and superior orientation, attached to the femur, was seen in one case. The ossification was present in the TCL in six cases, in the adductor magnus tendon in two cases, and in both in one case. The coronal plane was best in detecting and categorizing the ossification.Conclusion Our data indicate that ossification in PS disease is not confined to the TCL but may also involve the adductor magnus tendon. In some cases, it can be related to the anatomic proximity (overlap) of the fibers of these two structures. PS disease should not be regarded as synonymous with ossification of the TCL. The ossification may be classified into four types. No clinical differences among these types appear to exist.     

Injuries about the hip in the adolescent athlete

Athletic injuries in or around the hip in the adolescent athlete encompass possible causes such as a single, traumatic event to those of repetitive microtrauma. The injuries may involve the bone or the soft tissues, with former involving the epiphysis, apophysis, metaphysis, or diaphysis, whereas the latter includes muscles and tendons. With the improvements in surgical technique and instrumentation for hip arthroscopy and the development of magnetic resonance arthrography, clinicians have been able to diagnose and treat labral tears, hip instability, snapping hip, loose bodies, chondral injuries, and femoroacetabular impingement. The clinician needs to consider acquired conditions that may have coincidentally become apparent as a result of the adolescent's participation in an organized sports program. These include slipped capital femoral epiphysis, Legg-Calvé-Perthes disease, and pathologic lesions and fractures. This study reviews the more common acute and chronic overuse injuries in or around the hip in the adolescent athlete and discusses hip injury prevention in this active patient population.     

Acute tibial tubercleavulsion fractures

Acute tibial tubercle avulsion fractures are commonly seen in athletes involved with jumping sports, especially basketball. These injuries typically occur in well-muscled, mature-appearing boys, 15 to 16 years of age, who generate high tensile forces at the tubercle junction. Possible associated injuries include patellar and quadriceps tendon avulsions, as well as collateral and cruciate ligament and meniscal damage. Treatment is based on the magnitude of injury. Recovery is rapid and the outcome is usually excellent, even in type III injuries.     

The role of stretching in tendon injuries

The function of tendons can be classified into two categories: tensile force transmission, and storage and release of elastic energy during locomotion. The action of tendons in storing and releasing energy is mainly seen in sports activities with stretch-shortening cycles (SSCs). The more intense the SSC movements are (jumping-like activities), the more frequently tendon problems are observed. High SSC movements impose high loads on tendons. Consequently, tendons that frequently deal with high SSC motion require a high energy-absorbing capacity to store and release this large amount of elastic energy. As the elasticity of tendon structures is a leading factor in the amount of stored energy, prevention and rehabilitation programmes for tendon injuries should focus on increasing this tendon elasticity in athletes performing high SSC movements. Recently, it has been shown that ballistic stretching can significantly increase tendon elasticity. These findings have important clinical implications for treatment and prevention of tendon injuries.     

Imaging of the hamstrings

The hamstring muscles, located in the posterior thigh, include the biceps femoris, the semimembranosus, and the semitendinosus. The proximal portions of the hamstring muscles are subject to a variety of injuries and pathology. Many of these entities affect the origin of the hamstrings, including the tendinous enthesis, the underlying ischial tuberosity, and the surrounding tissues. Tendinosis and small partial tears at the origin are the result of chronic attrition. They may be accompanied by bursitis or hamstring syndrome. Apophysitis occurs in teenagers prior to complete fusion of the ischial apophysis and results from repeated traction injuries on the apophysis without discrete displacement. Abrupt injury at the origin from forced flexion of the hip results in osseous avulsions of the apophysis in teenagers and proximal tendon ruptures in adults. Other entities affect the muscles distal to the tendon origins. These injuries include strains and partial tears of the musculotendinous junction from acute indirect trauma, delayed onset muscle soreness from overuse of the muscle group without discrete remembered injury, and contusions and myositis ossificans from direct blunt impact. The imaging features of these injuries and pathology are fairly specific and diagnostic, with the exception of some cases of myositis ossificans and chronic ischial avulsions.     

Interference screws should be shorter than the hamstring tendon graft in the bone tunnel for best fixation

Purpose

Interference screw fixation of hamstring tendon grafts in bone has to overcome the challenges that tendons have a slippery surface and viscoelastically adapt under pressure. As the typical failure mode of the graft is to slip past the interference screw, it was hypothesized that the position and configuration of the graft end may be of influence on the fixation strength.

Methods

Different configurations of the graft ending and its effect to primary fixation with interference screws after viscoelastic adaptation were tested in six groups: I: graft and the screw inserted at the same depth, II/III: the graft overlaps the tip of the screw (interference screw of 28 and 19 mm in length, respectively), IV: strengthening of the graft ending with additional suture knots, V: Endopearl, respectively, and VI: effect of partial retraction of the screw after excessive insertion. In vitro tests were performed with fresh calf tendon grafts and interference screws in bone tunnels (fresh porcine distal femur) all of 8 mm in diameter.

Results

The relative position of the graft ending to the tip of the interference screw thereby was recognized as a significant factor on pullout forces. Further strengthening at the graft endings with additional suture knots or an Endopearl device could improve primary hold as well.

Conclusions

Better fixation strength is achieved if the tip of interference screw does not extend past the end of a tendon graft. Enforcement of the tendon end with sutures or an implant can further improve fixation.