Sports-Related Musculoskeletal Disorders
Reports on the Rheumatic Diseases Series 5 : Topical Reviews
- Overuse bone injuries are common in both the elite athlete and the recreational sportsperson. There are two categories – those that are due to pathology within the bone which may progress to stress fracture and those that result from excessive and repeated tractional forces on a musculotendinous attachment
- Tendon pain is common in both groups of athletes and is largely due to non-inflammatory tendinopathy
- Relative rest with active rehabilitation regimes are the mainstay of treatment for traction-type bony injuries. Complete rest is only appropriate for certain stress fractures
- Imaging has revolutionised both the diagnosis and the accurate staging of these bony and soft tissue pathologies
Introduction
Musculoskeletal problems will affect everyone who exercises or plays sport at some time. This may take the form of an acute injury or a more chronic complaint. Acute problems requiring medical intervention will usually be managed in the community, or in Accident & Emergency or orthopaedic departments. Chronic musculoskeletal complaints will, however, present to a variety of professionals, including rheumatologists. The spectrum of musculoskeletal disorders related to sport/exercise is extremely wide, so this review highlights the management of one particular group of disorders, the overuse injury in sport.
Overuse injuries are common, they are all too frequently associated with significant sporting morbidity, and, in our experience, outside of specialist clinics management is variable. In this review we will cover the assessment, diagnosis, management and, perhaps most importantly, the prevention of overuse injury to the muscle–tendon–bone unit. In so doing we hope to provide the reader with pragmatic advice that will have clinical relevance to their own practice. Our advice is based both on our own clinical experience and on published work. For those wishing to explore overuse injury further we have provided a recommended reading list.
Overuse bone injury
'Overuse injury to bone' essentially refers to stress fracture. Stress fractures can occur in any bone1 and affect individuals of all ages.2 In contrast to the insufficiency fracture seen by rheumatologists in osteoporotic patients we are focusing on stress fractures occurring in normal bone. That is not to say of course that whenever a stress fracture is diagnosed the possibility of underlying bone pathology should not be considered and excluded. We have both diagnosed osteopenia and osteoporosis in athletes who, on the face of it, appeared to have an overuse stress fracture.
Stress fractures occur as a result of microfracture from repetitive loading below a single load fracture threshold. Histological changes develop prior to a microfracture;3 if load is not modified a complete fracture will occur.
Assessment
Stress fractures can be very challenging to manage and unfortunately can take months to heal, so prevention or at least early recognition is essential. Whenever someone presents with musculoskeletal pain ask yourself, 'Could this be a stress fracture?' There are nearly always diagnostic clues – if care is taken with the history, the examination and investigation should serve as confirming what is already suspected.
The following diagnostic clues should raise the possibility of a stress fracture:
- Symptoms started after a significant increase in activity (breaking 'the 10% rule', viz only increase activity by 10% each week; don't increase both intensity and time by 10% at the same time)
- Weight-bearing pain that progresses with continued activity to non-weight-bearing pain
- Focal bony tenderness (especially tibia and ankles/feet)
- Pelvic (pelvis/sacrum) and groin (femur) pain
- Lower limb pain in a runner
- Unremitting focal lumbar pain on extension (pars interarticularis fracture)
- Lateral rib pain (particularly in rowers, due to pull of serratus anterior).
Investigation
The best investigation is a thorough history. Examination, and particularly bony tenderness, is supportive. Radiological examination is essential, but blind screening is often unhelpful or misleading. Stress fractures cause well-localised pain, so a plain x-ray remains a good starting point. A normal x-ray does not exclude a stress fracture, so if the clinical suspicion remains proceeding to a magnetic resonance imaging (MRI) scan of the area of concern is appropriate. While MRI may show an actual fracture line the typical MRI abnormality is periosteal and marrow oedema. Isotope bone scans may also show stress fractures but are non-specific and rarely needed beyond investigating rib fractures. Single photon emission computing tomography (SPECT) scans (followed by a reverse gantry CT scan if positive) can be useful if a pars fracture is strongly suspected despite a normal MRI. CT adds detail but with the exception of the further assessment of the pars interarticularis is not often needed. Ultrasound scanning may be diagnostic in cases with a fracture line, and thus a cortical break,4 but is not advocated in isolation.
Stress fractures cause pain and pain eases with healing. The routine use of sequential imaging is unnecessary unless there is clinical concern.5
Management
Absolute rest is almost never an essential part of the treatment. Moreover, such advice to anyone who is serious about their exercise may well lead to a loss of confidence. Relative rest to achieve pain relief combined with a means of maintaining some fitness is essential and is a principle much more readily accepted by athletes. Immobilisation of a fracture site while weight-bearing in a functional Aircast® brace is often effective, with the advantage that the splint can be removed when not weight-bearing. Plaster casts are now seldom necessary except for occasional patients who may be tempted to bear weight without the Aircast® splint in place. Surgical fixation is also usually unnecessary but is the management of choice in some circumstances (see below). The common stress fractures are listed in Table 1 with notes on aspects of management requiring particular care.
| TABLE 1. Common or problematic stress fractures. | ||
|---|---|---|
| Site of stress fracture | Sport/activity | Management or special consideration |
| Anterior rib (usually 2–10) | Rowing, kayaking (= pull of serratus anterior) | Relative rest |
| Pars interarticularis | Cricket fast bowling, gymnastics, diving (= spinal rotation into extension) | Relative rest usually adequate |
| Pelvis and sacrum | WB activity | Relative rest |
| Femoral neck | Distance running | Distraction side (superior) requires urgent surgical review. Compression (inferior) side can be managed with NWB and relative rest |
| Tibia | Distance running | Anterior tibial (distraction) and medial (compression) can be managed with Aircast® brace followed by gradual reintroduction of WB. Distraction fractures usually require prolonged treatment (6–12 months) |
| Calcaneum | Distance running | NWB immobilisation (Aircast®) for 2–4 weeks followed by gradual reintroduction of WB |
| Navicular bone6 | Athletics, football, rugby | NWB plaster cast immobilisation for 6–8 weeks. Some advocate surgical fixation but we have successfully managed conservatively |
| 2nd metatarsal | Ballet, dancing | NWB immobilisation (Aircast®) for 2 weeks with partial WB for further 2 weeks |
| 5th metatarsal | Ballet, endurance WB, tennis | NWB plaster cast immobilisation for 6–8 weeks or surgical fixation |
| Sesamoid bone | Ballet, dancing, running | NWB immobilisation (Aircast®) for up to 6 weeks |
| NWB non-weight-bearing; WB weight-bearing |
Prevention
Treating a stress fracture is a challenging prospect for both the patient and the clinical team and prevention is clearly better than cure. In a person with normal bone, virtually all stress fractures are probably avoidable as they reflect excessive load. Nonetheless, the reality is that individuals unintentionally put themselves at risk or are put at risk by the advice/direction of others.7-11 The following advice will help minimise that risk:
- Allow adequate time for training; accelerated training schedules seen particularly among those preparing for marathons are a common precipitating factor.
- Stick to the 10% rule (only increase activity by 10% each week; don't increase both intensity and time by 10% at the same time).
- Aim for quality of training, not quantity of effort.
- Utilise cross-training to maintain/improve fitness.
- Runners should consider the impact factor of running on hard man-made surfaces and try to incorporate off-road running.
- Use the correct equipment, particularly footwear. Runners should rotate their shoes and replace regularly (every 5–600 miles) as adequate shock absorption is time limited.
- Don't ignore weight-bearing pain that persists.
Osteitis, periostitis and apophysitis
These conditions can also be considered under the umbrella of an overuse injury to bone.
Osteitis
Osteitis as an overuse injury is best illustrated by osteitis pubis (inflammation of the symphysis pubis), a condition that plagues sports that require repetitive rotational movements through the groin, e.g. football and rugby. Osteitis pubis occurs as a consequence of chronic pelvic instability. This may relate to functional muscular instability with no actual structural pathology but more often there is evidence of adductor tendinopathy or tear and conjoint tendon tear ('sports hernia').12 Osteitis pubis is frequently confirmed on x-ray alone; however MRI changes are characteristic. MRI is additionally useful in delineating the complex and overlapping pathology which characterises the unstable pelvis.13 Management aims to rectify pelvic instability as a general principle while managing the individual pathology of pelvic instability syndrome.
Periostitis
Periostitis is an inflammatory reaction at the point of tendinous attachment to bone, best exemplified in an exercising population by medial tibial traction periostitis (MTTP), more commonly but unhelpfully known as 'shin splints'. MTTP is typically seen in weight-bearing (running, jumping) sports, often in individuals with musculotendinous calf, peroneal and tibialis posterior tightness, and is related to overuse. Patients typically complain of diffuse medial tibial pain with tenderness along the posterior tibial border. Unlike the tibial pain of a stress fracture – which is usually focal – the pain eases with warm-up, only to recur following exercise. The tibia was previously thought to be the source of pain; however it seems more likely that the soleus and flexor digitorum longus are implicated.14
The exact trigger of MTTP remains in some doubt, although biomechanical factors including excessive pronation have all been implicated at some point.15-16 MTTP appears to be more common in females.17
MRI and bone scan demonstrate diffuse change corresponding to the site of tenderness, in contrast to the more focal abnormality seen with a tibial stress fracture.
What is clear to all who treat MTTP is that it is a chronic problem which is difficult to manage. Management involves withdrawal from provoking weight-bearing activity, improvement of soft-tissue flexibility through soft-tissue manual treatments and physiotherapy, and the gradual reintroduction of activity. Any biomechanical issues should be addressed. Surgical release can be effective in resistant cases.
Apophysitis
Apophysitis is a condition of the growing skeleton, which rheumatologists often see in children with Osgood–Schlatter disease. The weak point of the muscle–tendon–bone unit in an adult is usually the tendon, hence the prevalence of tendinopathy. In a child the functional weak point is usually the apophysis and apophysitis refers to inflammation and separation of the apophysis. Whether apophysitis is a true overuse syndrome is uncertain;18 it seems to occur in some children at the time of a growth spurt irrespective of their level of exercise. It is more likely to come to medical attention in those who exercise, merely because they are more likely to experience symptoms. There are a number of vulnerable apophyses reflecting different tendon attachments (see Table 2), most of which can be managed symptomatically with relative (not absolute) rest and stretching along with ample reassurance. Occasionally actual avulsion of the apophysis may occur. This can usually be managed conservatively. However if there is marked separation, as at a hamstring, surgical repair should be considered.19
| TABLE 2. Common sites of apophysitis in athletes. | |
|---|---|
| Tendon and apophysis | Eponymous syndrome |
| Distal patella on tibial tuberosity | Osgood–Schlatter |
| Proximal patella on inferior patella pole | Sinding-Larsen–Johansson |
| Achilles on calcaneum | Sever's18 |
| Tibialis posterior on tarsal navicular | - |
| Peroneus brevis on base of 5th metatarsal | - |
| Hamstring on ischial tuberosity | - |
| Rectus femoris on anterior inferior iliac spine | - |
| Sartorius on anterior superior iliac spine | - |
| Iliopsoas on lesser trochanter | - |
Tendinopathies
The diagnosis and management of exercise-related tendinopathies has changed dramatically in recent years. Previously both acute and chronic tendon pain were labelled 'tendinitis' and were presumed to be inflammatory in nature, with rest and anti-inflammatory medication being the treatment of choice. Research and experience has now shown this to be an oversimplification of what is actually a complex mixture of varying pathologies, from an acute tendinopathy to the more chronic pathology of tendinosis.20
Although prevalent in most sports, tendinopathies are particularly associated with certain activities. Jumpers may suffer the aptly named 'jumper's knee', involving the patellar tendon, while tennis players suffer a similar injury affecting the common extensor origin of the elbow ('tennis elbow'). The Achilles tendon is frequently affected in runners, with throwers experiencing similar problems at the rotator cuff.
Tendon injuries constitute 15–30% of soft-tissue athletic injuries. Athletes often present with pain and stiffness which progress, increasing in intensity until training becomes impossible. The diagnosis can often be made on history alone, with examination confirming the presence of localised tenderness, swelling, weakness and, in the more chronic cases, muscle wasting. Ultrasound (Figure 1) and/or MRI scanning may confirm the diagnosis by demonstrating an area of increased hypoechogenicity.
FIGURE 1. Ultrasound of knee showing patellar tendinosis of the right knee in a recreational rugby player. The left knee (a) is normal (inferior pole of patella on left of screen), whereas the right knee (b) demonstrates extensive thickening and low echogenicity due to granulation tissue and disruption of normally dense collagen fibres.
(Reproduced with permission from Higgins R, Brukner P, English B (ed). Essential sports medicine. Oxford: Blackwell Publishing; 2006).
Management is dependent on the underlying pathology. The initial acute presentation is usually with a fairly short history of pain and stiffness, invariably following a period of sudden increase or change in training intensity. The underlying pathology is inflammation on a background of microtears triggered by the overload. Initial rest, ice and physiotherapy with a gradual return to training often suffices in these individuals. Recovery takes several weeks but may take longer in the older athlete.
Recurrent episodes, or incomplete resolution of an initial episode, may lead on to the much more problematic and more predominant pathology that is referred to as tendinosis.21
Pathologically, there is breakdown of cross-linkages within the tendon collagen. The condition is, in the main, a non-inflammatory one and includes mucoid cyst formation, with the matrix being replaced by glycosaminoglycan ground substance. Increased vascularity is demonstrated on Doppler ultrasound scanning. The final pathology in chronic cases is described as angiofibroblastic hyperplasia, showing increased cell numbers and blood vessels but no inflammatory cells of note.22
The condition of tendinosis has been described as a degenerative one but in reality it is more appropriate to regard the tendon as having undergone an abnormal healing process post injury. Although this condition is a common curse of athletes over 30 years of age, it is also prevalent in the younger athlete. Patellar tendinosis, in particular, can present in the late teens, sometimes significantly compromising the chances of a talented sportsperson reaching their potential at an elite level.
The treatment of the acute and chronic tendinopathy differ. In the acute phase loading with exercise at too early a stage risks deterioration and progression, so that this presentation, especially in the younger athlete, is treated with rest, ice and a physiotherapy approach which is quite conservative when compared with the management of a more chronic tendinopathy.
In chronic tendinopathy the affected tendon must be loaded progressively. 'Eccentric' exercises (lengthening the musculotendinous unit while contracting the muscle, so producing a greater load on the structures, as opposed to 'concentric' exercise where the musculotendinous unit shortens and contracts), initially using body weight and then progressively increasing the load with weight being added, are appropriate. For instance single leg squats, often on a decline board, are used in the rehabilitation of a patellar tendinopathy and an initial regime may comprise two sets of 20 repetitions using body weight but progressing to various exercises such as the seated leg press, where the load can be safely increased to a significant level. Elite athletes may also incorporate exercises such as lunges and 'cleans' (Figure 2), using free weights as the rehabilitation progresses.23,24
FIGURE 2. Demonstration of an athlete undertaking a lunge. Weights are added to this movement as the rehabilitation progresses.
(Reproduced with permission from Higgins R, Brukner P, English B (ed). Essential sports medicine. Oxford: Blackwell Publishing; 2006).
Most of the published work on the rehabilitation of an Achilles tendinopathy uses body weight with single leg heel drops to load the tendon, with up to 70 repetitions being used and further load then being added by the wearing of a weighted rucksack.25
Similar eccentric exercises are used to strengthen the common extensor origin when it is implicated, usually, as noted above, in racket sports. A simple approach for those who do not have access to a gym is to use a broom, holding it halfway down with the arm bent and pronating and supinating the forearm. As rehabilitation progresses the patient moves their hand further down the broom 1 cm at a time, this having been marked off previously to assess progress.
The real difficulty in dealing with a tendinopathy is when a patient fails to respond to the conservative exercise therapy described above. There are many medical interventions that have been tried, all working sporadically, but on the whole being unreliable.
Previously a trial of corticosteroid injections would be followed, if unsuccessful, by surgical decompression and debridement. The former treatment is almost universally discouraged now due to the potential risk of rupture following injection. One possible explanation for this is that corticosteroid may weaken the already compromised collagen matrix; however, this has not been demonstrated in appropriate studies and it appears more likely that removal of pain allows the athlete to overload the degenerate tendon, so predisposing it to rupture.
Surgical intervention is still a treatment of choice, but many surgeons agree it is a last resort and encourage all other treatment routes to be explored.
Encouragingly there are a few new approaches which seem to be producing results.
Prolotherapy (sometimes described as sclerosant therapy) has been used for several decades to treat other conditions such as chronic back pain and is enjoying a resurgence as a treatment for this condition. The aim is to ablate the new vessels (neovascularisation) which are thought to promote pain either through delivering increased concentrations of chemical mediators to the area or by allowing new nerve ingrowth with the vessels.26 The number and size of the vessels appears to have an effect on prognosis.
More recently dry needling (a procedure in which the tendon is needled using a green needle under local anaesthetic cover) and the use of autologous blood injections have been trialled and the anecdotal but as yet unpublished results appear very encouraging. In the latter procedure, the tendinotic area is again needled under local anaesthetic cover and then 1–2 ml of the patient's own blood is injected into and around the tendinotic portion of the tendon. The rehabilitation programmes described above are then followed, with the emphasis being more on low repetitions and higher load.
Summary
Clearly the tools available to assist with diagnosis and management of overuse bone injury and tendon pathology have changed dramatically over the last decade. Further research is still necessary and is continuing in this area, and the exact mechanism by which these interventions produce the desired result is not always clear. We have, however, moved on from the era of the suggestion that 'Rest must be enforced, uninterrupted and prolonged' (Hugh Owen Thomas 1874) which has dominated treatment regimes until quite recently. Well-constructed progressive exercise rehabilitation programmes are now the cornerstone of managing many of the above-mentioned pathologies and this approach empowers the patient/athlete, involving them in both their treatment and, hopefully, successful recovery.
Further reading
Brukner P, Kahn K. Clinical sports medicine. North Ryde, NSW, Australia: McGraw Hill; 2006.
Higgins R, Brukner P, English B (ed). Essential sports medicine. Oxford: Blackwell Publishing; 2006.
Raven PB. Lower extremity [Clinical Supplement]. Med Sci Sports Exerc 2000;32(9 Suppl).
References
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- Heyworth BE, Green DW. Lower extremity stress fractures in pediatric and adolescent athletes. Curr Opin Pediatr 2008;20(1):58-61.
- Li GP, Zhang SD, Chen G, Chen H, Wang AM. Radiographic and histologic analyses of stress fracture in rabbit tibias. Am J Sports Med 1985;13(5):285-94.
- Banal F, Etchepare F, Rouhier B et al. Ultrasound ability in early diagnosis of stress fracture of metatarsal bone. Ann Rheum Dis 2006;65(7):977-8.
- Brukner P, Bennell K, Matheson G. Stress fractures. Melbourne, Australia: Blackwell Science Asia; 1999.
- Khan KM, Fuller PJ, Brukner PD, Kearney C, Burry HC. Outcome of conservative and surgical management of navicular stress fracture in athletes: eighty-six cases proven with computerized tomography. Am J Sports Med 1992;20(6):657-66.
- Kelsey JL, Bachrach LK, Procter-Gray E et al. Risk factors for stress fracture among young female cross-country runners. Med Sci Sports Exerc 2007;39(9):1457-63.
- Milner CE, Ferber R, Pollard CD, Hamill J, Davis IS. Biomechanical factors associated with tibial stress fracture in female runners. Med Sci Sports Exerc 2006;38(2):323-8.
- Warden SJ, Creaby MW, Bryant AL, Crossley KM. Stress fracture risk factors in female football players and their clinical implications. Br J Sports Med 2007;41 Suppl 1:i38-43.
- Greeves JP, Leamon SM, Bunting A et al. Risk factors for stress fracture injury in British Army Junior Entry recruits. Med Sci Sports Exerc 2007;39(5 Suppl):S393.
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- Macintyre J, Johson C, Schroeder EL. Groin pain in athletes. Curr Sports Med Rep 2006;5(6):293-9.
- Cunningham PM, Brennan D, O'Connell M, MacMahon P, O'Neill P, Eustace S. Patterns of bone and soft-tissue injury at the symphysis pubis in soccer players: observations at MRI. Am J Roentgenol 2007;188(3):W291-6.
- Beck BR, Osternig LR. Medial tibial stress syndrome: the location of muscles in the leg in relation to symptoms. J Bone Joint Surg Am 1994;76(7):1057-61.
- Bennett JE, Reinking MF, Pluemer B, Pentel A, Seaton M, Killian C. Factors contributing to the development of medial tibial stress syndrome in high school runners. J Orthop Sports Phys Ther 2001;31(9):504-10.
- Pell RF 4th, Khanuja HS, Cooley GR. Leg pain in the running athlete. J Am Acad Orthop Surg 2004;12(6);396-404.
- Burne SG, Khan KM, Boudville PB et al. Risk factors associated with exertional medial tibial pain: a 12 month prospective clinical study. Br J Sports Med 2004;38(4):441-5.
- Ogden JA, Ganey TM, Hill JD, Jaakkola JI. Sever's injury: a stress fracture of the immature calcaneal metaphysis. J Pediatric Orthop 2004;24(5):488-92.
- Servant CT, Jones CB. Displaced avulsion of the ischial apophysis: a hamstring injury requiring internal fixation. Br J Sports Med 1998;32(3):255-7.
- Khan KM, Cook JL, Taunton JE, Bonar F. Overuse tendinosis, not tendonitis. Part 1: A new paradigm for a difficult clinical problem. Phys Sportsmed 2000;28(5):38-48.
- Khan KM, Cook JL, Bonar F, Harcourt P, Astrom M. Histopathology of common tendinopathies: update and implications for clinical management. Sports Med 1999;27(6):393-408.
- Movin T, Gad A, Reinholt FP, Rolf C. Tendon pathology in long-standing achillodynia: biopsy findings in 40 patients. Acta Orthop Scand 1997;68(2):170-5.
- Cook JL, Khan KM. What is the most appropriate treatment for patellar tendinopathy? Br J Sports Med 2001;35(5):291-4.
- Cook JL, Khan KM, Purdam CR. Masterclass. Conservative treatment of patellar tendinopathy. Phys Ther Sport 2001;2(2):54-65.
- Alfredson H, Pietilä T, Jonsson P, Lorentzon R. Heavy-load eccentric calf muscle training for the treatment of chronic Achilles tendinosis. Am J Sports Med 1998;26(3):360-6.
- Khan KM, Cook JL, Maffulli N, Kannus P. Where is the pain coming from in tendinopathy? It may be biochemical, not only structural, in origin [erratum in Br J Sports Med 2000;34(4):318]. Br J Sports Med 2000;34(2):81-3.
| Editor's note: A report in the arc Hands On series on the use of musculoskeletal ultrasound in primary care is in preparation and scheduled for publication in October 2008. |
