Hamstring injuries have been consistently identified as the commonest injuries sustained in running and sprinting athletes (Drezner, 2003). Reoccurring hamstring injuries are frequently reported in comparison to other musclo-skeletal injuries (Woods et al., 2004), this would suggest that misdiagnosis and or poor management/rehabilitation could be a major factor upon initial presentation, thus the alarmingly high reoccurrence rate.
Many studies have examined alleged predisposing factors to hamstring injury, such as insufficient warm up, poor flexibility, fatigue, muscular imbalances and poor muscular strength with conflicting results (Foreman et al., 2006). Originally, poor flexibility of the hamstrings was thought to be the major cause of injury, however studies by Bennel et al. (1999), Rolls and George (2004), report no significant relationship between hamstring length and injury.
Anatomically the hamstring muscles cross two joints, which through resulting increased tensile forces are inherently more susceptible to injury. The hamstring muscles are innervated by the sciatic nerve which emerges from the lumbar spine at L5-S3 and travels posteriorly down the thigh where it splits above the knee. The nerve can become irritated, tethered or inflamed at any point along its pathway with the potential to refer symptoms distally. For this reason, clinicians should integrate neurological testing into the assessment and treatment of hamstring injuries.
Differential Diagnosis This assignment will discuss the commonest causes of recurrent hamstring problems that are likely to be presented, but the clinician must consider and exclude a number of other causes such as neoplasms, avulsion fractures, DVT’S, bursitis, and muscular apophysitis. Hamstring strain: It is unlikely that this is a hamstring strain, as the runner is a distance athlete who tends to gradually change running speed, and the nature of his activity is that he is not required to change speed rapidly or explosively.
The runner does not report an acute episode of injury and he reports a gradual onset of discomfort whilst out running. There is no palpable tenderness at the musclo-tendinous junction. There has been no sign of bruising, resisted hamstring tests display slight weakness but are pain-free. Positive straight leg raise (SLR) was displayed but as resisted tests were pain free, this condition was excluded.
Hamstring syndrome: No traumatic incident reported by the runner which fits this condition, however no gluteal symptoms were reported and there was no palpable tenderness around the ischial tuberosity or the sciatic nerve. The runner displayed a positive SLR with ankle dorsi-flexion (ADF) which was aggravated with internal rotation. However, the slump test can display normal with this condition as nerve tethering occurs below the pelvis.
Posterior compartment syndrome: Although reported to be very uncommon, chronic forms have been associated with distance runners (Read, 2000). This condition gradually becomes more painful with exercise but pain subsides quickly when provoking activity stops. This is not the case with our runner, our runners’ SLR was positive and markedly reduced (SLR should be negative with posterior compartment syndrome) and a slight weakness was displayed on resisted tests although they were pain-free. Immediate rest does not relieve our runners’ symptoms and SLR and muscular weakness exclude this condition.
Piriformis syndrome: Pain felt in the buttock where the piriformis muscle is inflamed/in spasm where the sciatic nerve passes through the muscle. Therefore, this condition can give referred pain. This is tender to palpitation. The runner had no symptoms in the buttock and resisted external hip rotation was normal and pain-free, therefore this condition was excluded. This condition although documented extensively in the literature may be commonly misdiagnosed; out of 640 cadaver limbs examined, only in 12% of the limbs did the sciatic nerve pass through the piriformis muscle (Agur & Lee, 1999).
Adverse neural tension/Lumbar spine pathology: The runner complained of gradual onset of pain whilst out running which had a frequently increasing amount of episodes. More recently, he described that he felt a constant ache in his posterior thigh. The runner also complained that his back became stiff and sore when he sat down at work for prolonged periods, which he was able to relieve when he stood up. Active lumbar flexion at end of range was painful, side flexion to the right was restricted and extension generally stiff and sore. Observation of posture revealed a sway to the left away from the pain.
Resisted hamstring and hip extension were slightly weak (4/5), but generally pain-free. SLR with ankle dorsi-flexion was painful and aggravating; but when ankle dorsi-flexion was released, the patient was able to achieve a greater range of SLR until pain and resistance was encountered. Slump test was painful with a significant reduction in knee extension. The subjective/objective assessment indicated that the runners’ symptoms had a neurogenic orgin from the lumbar spine. The runner was diagnosed with a Lumbar disc herniation (LDH) of L5/S1 with a possible spinal stenosis. This was thought to be a posto-lateral herniation due to the restriction of side flexion and the symptoms being in one leg only.