Investigating the effectiveness of extracorporeal shockwave therapy at reducing pain in patients with chronic patellar tendinopathy when compared to exercise

Abstract

1.1 Chapter Description: This chapter serves to introduce the PICO review, firstly by describing patellar tendinopathy (PaT) and its impact on the population. The mechanisms and effects of extracorporeal shockwave therapy (ESWT) will also be briefly discussed, before finally outlining the research question this dissertation will aim to answer. 6.5 PaT and ESWT: Patellar tendinopathy (PaT), also known as jumper’s knee, is a prevalent musculoskeletal disorder characterised by pain and dysfunction in the patellar tendon, commonly affecting athletes engaged in sports which involve repetitive jumping and running. PaT commonly presents as anterior knee pain, at the inferior base of the patella, that may be exacerbated during activities that store and release energy in the patellar tendon (Malliaras et al. 2015). This condition has gained considerable attention in both sports medicine and orthopaedics due to its high incidence among athletes, and its potential to impact performance and career longevity (De Vries et al. 2017). ESWT is a non-invasive application of acoustic waves which was originally used to treat urological conditions, however is frequently used in a variety of musculoskeletal conditions such as plantar fasciitis, lateral epicondylitis of the elbow, achilles tendinopathy as well as patellar tendinopathy. While ESWT is used to disintegrate kidney stones in urolithiasis, it does not disintegrate tissue in musculoskeletal applications but aims to facilitate tissue repair and regeneration, such as when applied in cases of PaT (Wang 2012). 6.5 Epidemiology and Impact of PaT: PaT commonly affects athletes who use the patellar tendon repeatedly for energy storage and energy releasing activities such as jumping. This has led to PaT frequently being referred to as “jumper’s knee”, and it is more commonly seen in sports involving repetitive jumping. A meta-analysis by Nutarelli et al (2023) found that volleyball and basketball were the sports most commonly affected, with an incidence rate of around 20-25% in these particular athletes. This meta-analysis also estimated that PaT has a prevalence of 18.3% in the sports active population, as it is also frequently exhibited in other athletes such as runners and football players. The same meta-analysis found that PaT is more commonly seen in older athletes than in younger athletes, with the prevalence in older athletes found to be twice as high. Additionally, non-elite athletes were found to have higher PaT prevalence and incidence rates than elite athletes. While elite athletes typically train at a higher frequency and intensity than non-elite athletes and thus expose the patellar tendon to higher loads, they also build a higher tendon-load capacity through properly planned and progressed training and competition, which may explain why PaT is less common in such elite athletes (Nutarelli et al. 2023). No significant difference in incidence between athletes of different sexes has been conclusively proven. Differing results have been found in different studies, but ultimately there is not enough literature present to adequately determine whether sex hormones affect the response of the patellar tendon to load and ultimately PaT symptoms (Longo et al. 2011). [...]