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Injection therapy

Injection therapy

Fares Haddad and Ademola Adejuwon explain the range of options to help speed recovery from muscle damage

Injury to skeletal muscle, involving damage to a muscle or its tendon, is a common occur- rence among sports participants. The resulting pain, swelling and muscle spasm may temporarily disable the individual, and in the case of athletes may lead to significant loss of training and playing time. We look here at a number of injection therapy options that are now available to help therapists in the management of musculo-tendinous injuries.

Pathology of muscle injury

Injury to muscles occurs either as a strain/pull or as a muscle tear. A muscle straintends to be the result of overuse or overstretching, with damage commonly located at the musculo-tendinous junction (although the strain may also be across the belly or through the origin or insertion of the muscle).

A muscle tearis rupture to part or all of the muscle fibres, usually caused by maximal strain during eccentric contraction of the muscle group. Damage mostly occurs at the musculo-tendinous junction.

In both cases, the healing process is the same:

* degradation

* inflammation

* regeneration

* repair/fibrosis.

The inflammatory process recruits cells to the injured area to repair and regenerate damaged tissues. This is usually associated with pain and can occur quickly over a few days (acute inflammation) or may be prolonged where there is persistent aggravation to the tissues (chronic inflammation).

Healing after trauma is a balance between the processes of regeneration and repair. Fibrotic scar tissue consists of tight bundles of non-elastic collagen fibres, which are susceptible to tearing. The size and strength of the resultant scar tissue, which is infiltrated by regenerating myofibrils (the contractile filaments within muscle fibre), determines how successfully the muscle group recovers.

The purpose of managing muscle injury is to improve regeneration, regulate inflammation and reduce scar formation.

Current management of muscle injuries

After acute (traumatic) muscle injury the first-line treatment is rest, ice, compression and elevation (RICE). These simple actions reduce the localised swelling and pain that the inflammatory response produces. Nonsteroidal anti-inflammatory drugs (NSAIDs) will also decrease excessive swelling and pain.

For most soft-tissue injuries this combination of treatments, along with physical rehabilitation, is usually sufficient to recover effective muscle function. But the healing process takes time, during which the individual must refrain from their usual sports routine (indeed, pain and inflammation may make activity impossible). And it is in situations where the layoff time is of professional or commercial significance that clinicians have sought other ways to expedite the athlete’s recovery.

Corticosteroid injection therapy

Corticosteroids are anti-inflammatory drugs. By inhibiting the accumulation of neutrophils and inflammatory mediators (immune system cells that flood the site of damage), corticosteroids reduce the local inflammatory response and severity of pain. There is a delayed response to steroid injec- tion but the analgesic effect may last for several weeks: evidence shows mild to moderate pain relief lasting for six to eight weeks after muscle injury(1).

Steroids are usually administered in combination with a local anaesthetic around the damaged muscle or into the peritendinous region (soft tissue around the tendon). This is often done under ultrasound guidance, to pinpoint the area of damage. In acute (traumatic) injuries steroid/anaesthetic therapy provides early pain relief, enabling the individual to get back to normal activity (assuming no significant structural damage) and allowing for objective assessment of the extent of injury. This treatment can also bring early rehabilitation and thus a reduction in subsequent injury risk.

The downside of using anti-inflammatory agents is that they can delay healing and scar formation, thereby risking re-injury. This is because of the way the injections act to alter the inflammatory response, interfering with the recruitment of cells for tissue repair. Among patients on long-term steroid therapy it is common to see not just slow healing but also tissue atrophy and increased risk of infection.

These adverse effects of corticosteroid treatment have brought about the development of new injection therapies, to provide analgesia without adversely affecting local tissue repair.

Traumeel

Traumeel is a homeopathic combination drug which reduces inflammation, swelling and oozing. The pharmacology involved is not yet understood; studies suggest that the drug modifies the action of neutrophils and the release of inflammatory mediators(2). Injected locally, its analgesic effect is compa- rable to steroids but without the risks of tendon rupture or skin depigmentation. A relatively old drug (available for 80 years), Traumeel is licensed for frequent use, with the only contraindication being adverse allergic reaction. Among elite athletes its use is common and anecdotally it attracts very favourable reports. There is data to suggest comparable efficacy of both topical and injected Traumeel when compared with NSAID therapy, with fewer side effects and greater patient satisfaction(3,4).

Actovegin

The drug Actovegin was initially licensed for intravenous use to improve cellular oxygen transport to tissues in patients with arterial disease. As a gel or cream it is also used to treat slow-healing skin lesions such as burns or skin-grafted wounds. In recent years it has gained notoriety for its use by elite cyclists as a performance-enhancing drug, with the consequence that the World Anti-Doping Agency (WADA) has banned its use in competition.

Actovegin is a protein-free derivative of calf’s blood, rich in electrolytes, trace elements and various organic components. It improves tissue uptake and use of glucose and oxygen; hence it can be used to improve the oxygenation and energy supply to muscles after injury. Patients receiving Actovegin injections for muscle injury resumed full sporting activity in a clinically significant reduced timescale when compared with placebo(5). Actovegin may thus be used to accelerate the healing of muscle injuries acquired through trauma or overuse.

Autologous blood/conditioned serum

The regeneration of injured muscle is dependent on growth factors found in blood. Platelets, in particular, are a rich source of growth factors, and can be isolated by spin- ning down whole blood. Whole blood can also be stimulated to increase the concentration of the desired growth factors (FGF, HGF, TGF-beta1), which can then be isolated as a ‘conditioned serum’.

The guided injection of blood or serum into inflamed muscle tissue, although initially sometimes acutely painful, leads to an overall reduction in pain and disability and shortens recovery time(6). In one study, when compared to Traumeel and Actovegin, athletes treated with autologous conditioned serum (ACS) showed significantly reduced recovery time(7). The observed accelerated recovery was confirmed by MRI, suggesting that ACS injection therapy is a promising treatment. It is mostly used to treat tendinopathies.

Aprotinin

Recent research has looked at how to control the extent of degradation and subsequent fibrosis after soft-tissue injury. Matrix metalloproteinase (MMP) are enzymes associated with damaged tissue that cause the break- down of extracellular matrix and inhibit collagenase enzyme, allowing tissue remodelling to occur. Some MMPs have been found in excessive amounts in patellar and rotator cuff tendinopathies and have been linked with the chronic nature of these conditions(8).

In order to control the cycle of degradation and repair, MMP inhibitors are being injected locally into sites of chronic inflammation. Aprotinin (Trasylol) is a broad-spectrum MMP inhibitor normally used to prevent blood loss during cardiac surgery. When injected into the peritendinous space in patellar and Achilles tendinopathy cases (two to four injections at fortnightly inter- vals), it provided better pain control than corticosteroid or placebo injections(9).

MMP inhibitors provide an alternative treatment for chronic tendinopathies, particularly where rest and anti-inflammatory approaches have been exhausted. The main side effect is a hypersensitivity reaction caused by repeat use; hence recurrent use is strongly contraindicated for a year after exposure.

Botulinum toxin

Chronic pain after muscle injury is thought to arise from muscle spasm: the reduced blood flow to muscles in spasm allows metabolic by-products to build up, stimulating pain receptors.

Spasm prevents movement in order to allow muscles to heal, but sometimes this can happen in a poor position or with tight scar tissue, resulting in further pain on movement, as is evident in some patients who suffer from escalating chronic back pain.

Muscle relaxants such as barbiturates have been used to treat chronic muscular pain; unfortunately they also have a sedative effect.

Botulinum toxin A is a neurotoxin that inhibits the transmission of acetylcholine across the neuromuscular junction; this stops the muscle from contracting but has no sedative effect. Injected locally, it temporarily paralyses painful muscles, facilitating physiotherapy and muscle healing.

In the treatment of lateral epicondylosis (tennis elbow), patients treated with botulinumtoxin showed marked improvement when compared with placebo injections(10). Results are comparable to surgical release(11). The evidence suggests that botulinumis beneficial for treating certain tendinopathies prior to surgical intervention. This is an outpatient procedure and does not impair the individual’s ability to work.

Patients receiving botulinuminjections for chronic low back pain have reduced pain and improved range of lumbar movement(12).

Epidural steroid injection (ESI)

ESI is a corticosteroid/anaesthetic injection therapy that has become one of the most commonly prescribed treatments for chronic low back pain. Injection is into the epidural space around the spinal nerve or the artic- ular facet. There is evidence to show it speeds recovery by providing symptomatic relief, thereby allowing other conservative measures to be undertaken(13). Its efficacy is, however, variable.

A new use of ESI is to treat hamstring injuries. The many theories about how and why hamstring injuries arise include poor warm-up technique, inadequate stretching and overtraining, with the most significant risk factor being previous hamstring injury(14). It has also been suggested that underlying neurogenic conditions such as spinal degeneration, disc herniation or uncontrolled movement of the lower back may be implicated(15).

Inflammation of the nerve roots causes a change to the basal tone of the hamstring muscles. Heavy exercise causes imbalances between the flexors and extensors, leading to muscle strain. The fact that hamstring injuries frequently recur suggests that we are not very good at managing this particular problem. One study of Australian football players found a rate of recurrence of hamstring injuries of 30.6% within a single season(16).

Epidural injections to the sacral region reduce sensitivity of the nerves, returning the muscle group to a normal resting tone. This would suggest that ESI, combined with other local therapies, may have a role to play in preventing and treating hamstring injuries.

Conclusion

In a sporting climate where physical prowess is rewarded by commercial success, elite athletes cannot afford to be injured. The constant pressure for speedy return to full activity has fuelled the search for new forms of treatment to expedite recovery. Although injected corticosteroids have diagnostic and therapeutic roles in both acute and chronic musculo-tendinous injuries, we have to remain cautious about their use because of the known complications.

Traumeel and Aprotinin provide good anti-inflammatory and analgesic alternatives for chronic muscle injuries and tendinopathies, with few contraindications. There is evidence to support the use of autol- ogous blood/serum injection for similar conditions, but in the strict world of compet- itive sport this line of therapy contravenes WADA regulations on the injecting of blood products. In the non-competitive athlete or sports enthusiast it can be considered as an option prior to surgical intervention.

In a similar fashion, the speedy recovery of large areas of muscle injury either through traumatic contusions or overuse can be encouraged with Actovegin. Although this substance is also banned in the professional arena, on a wider scale it may be beneficial in rehab.

Coupled with physiotherapy, botulinum toxin and ESI can be used as last resort treat- ment of chronic back pain. In a highly sensi- tive patient (star athlete) who suffers from recurrent hamstring injury, ESI can be used alongside physiotherapy to rehabilitate and possibly reduce future risk of injury.

References

1.Paolini, J and Orchard, J (2005) ‘The use of therapeutic medications for soft-tissue injuries in sports medicine’. MJA; 183 (7):384-388.

2.Porozov, S, Cahalon, L et al (2004) ‘Inhibition of IL-1βand TNF-αSecretion from resting and activated human immunocytes by the homeopathic medication Traumeel’ S Clinical & Developmental Immunology; 11 (2):143-149.

3. Schneider, C, Klein, P et al (2005) ‘A homeopathic ointment preparation compared with 1% diclofenac gel for acute symptomatic treatment of tendinopathy’. Explore(NY); Nov;1(6):446-52.

4. Birnesser, H et al (2004) ‘The homeopathic preparation Traumeel S compared with NSAIDS for symptomatic treatment of epicondylitis’. Journal of Musculoskeletal Research, Vol. 8, Nos. 2 & 3 119 -128.

5.Pfister, A and Koller W (1990) ‘Treatment of fresh muscle injury’. Sportverletz Sportschaden; Mar;4(1):41-4.

6.Edwards SG, Calandruccio JH (2003) ‘Autologous blood injections for refractory lateral epicondylitis’. J Hand Surg [Am];Mar;28(2):272-8.

7.Wright-Carpenter, T, Klein, P et al (2004) ‘Treatment of muscle injuries by local administration of autologous conditioned serum: a pilot study on sportsmen with muscle strains’. Int J Sports Med Nov;25(8):588-93.

8.Magra, M and Maffulli, N (2005) ‘Matrix metalloproteases: a role in overuse tendinopathies’. British Journal of Sports Medicine; 39:789-791.

9.Capasso, G, Testa, V et al (1997) ‘Aprotinin, corticosteroids and normosaline in the management of patellar tendinopathy in athletes: a prospective randomized study’. Sports Exerc Injury; 3: 111-115.

10.Placzek ,R, Drescher, W et al (2007) ‘Treatment of chronic radial epicondylitis with Botulinum toxin A: a double-blind,placebo- controlled, randomized multicenter Study’. J Bone Joint Surg Am; 89: 255-260.

11.Keizer, S, Rutten, HP et al (2003) ‘Botulinum toxin injection versus surgical treatment for tennis elbow: a randomized pilot study’. Clin Orthop Rel Res; 401:125-131.

12.Subin, B, Saleemi, S et al (2003) ‘Treatment of chronic low back pain by local injection of Botulinum toxin-A. The Internet Journal of Anesthesiology; Volume 6 Number 2.

13.McLain, RF, Kapural, L and Mekhail, NA (2005) ‘Epidural steroid therapy for back and leg pain: mechanisms of action and efficacy’. SpineJMar-Apr; 5(2):191-201.

14.Orchard JW (2001) ‘Intrinsic and extrinsic risk factors for muscle strains in Australian football’. Am J Spots Med; May :29;3 p300.

15. Szalai, K and Illyés, A (2005) ‘Sacral epidural steroid injections used for the prevention of hamstring injuries’. FACTA UNIVERSITATIS Series: Physical Education and Sport Vol. 3, No 1, pp. 37-44.

16.Orchard, J, Marsden, J, and Lord, S (1997) ‘Preseason hamstring weakness associated with hamstring muscle injury in Australian footballers’. Am J Sports MedJan :25;1 9 81

Injection therapy