Time to return to full training is delayed and recurrence rate is higher in intratendinous (‘c’) acute hamstring injury in elite track and field athletes: clinical application of the British Athletics Muscle Injury Classification

Can a Clinical Examination Demonstrate Intramuscular Tendon Involvement in Acute Hamstring Injuries?

Background:

Involvement of the intramuscular (central) tendon in acute hamstring injuries, as detected on magnetic resonance imaging (MRI), may prolong recovery times. To date, it is unclear whether hamstring injuries exhibiting intramuscular tendon involvement can be identified though routine clinical examinations that assess flexibility and strength.

Purpose:

To test whether MRI-detected intramuscular tendon involvement could be identified by a clinical assessment of muscle strength and flexibility.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

Participants were drawn from a multicenter randomized controlled trial on the effect of platelet-rich plasma in acute hamstring injuries. Clinical parameters assessed within 5 days of injury were active knee extension and passive straight-leg raise for hamstring flexibility and isometric knee flexion force with 15° and 90° of knee flexion. Also, 1.5-T MRI of the thigh was performed within 5 days of injury and was evaluated for the presence of different types of intramuscular tendon involvement. One-way analysis of variance was used to determine whether clinical parameters could discriminate injuries with intramuscular tendon involvement from those without such involvement.

Results:

A total of 74 acute hamstring injuries were included, with 52 (70.3%) injuries affecting the myotendinous junction. Injuries exhibiting intramuscular tendon discontinuity on MRI had an increased mean absolute flexibility deficit for active knee extension (20.4° ± 14.9° vs 10.7° ± 9.0°, respectively; P = .006) and decreased mean strength at 15° (62.2 ± 26.7 N vs 76.6 ± 22.5 N, respectively; P = .05) compared with injuries without intramuscular tendon discontinuity. Flexibility and strength showed major overlap and variance among injuries with and without intramuscular tendon involvement.

Conclusion:

Hamstring flexibility and strength cannot be used to discriminate the presence of intramuscular tendon involvement.

Intramuscular tendon involvement on MRI has limited value for predicting time to return to play following acute hamstring injury

Background

Hamstring injury with intramuscular tendon involvement is regarded as a serious injury with a delay in return to play (RTP) of more than 50 days and reinjury rates up to 63%. However, this reputation is based on retrospective case series with high risk of bias.

Objective

Determine whether intramuscular tendon involvement is associated with delayed RTP and elevated rates of reinjury.

Methods

MRI of male athletes with an acute hamstring injury was obtained within 5 days of injury. Evaluation included standardised MRI scoring and scoring of intramuscular tendon involvement. Time to RTP and reinjury rate were prospectively recorded.

Results

Out of 70 included participants, intramuscular tendon disruption was present in 29 (41.4%) injuries. Injuries without intramuscular tendon disruption had a mean time to RTP of 22.2±7.4 days. Injuries with <50%, 50%–99% and 100% disruption of tendon cross-sectional area had a mean time to RTP of 24.0±9.7, 25.3±8.6 and 31.6±10.9 days, respectively. Injuries with full-thickness disruption took longer to RTP compared with injuries without disruption (p=0.025). Longitudinal intramuscular tendon disruption was not significantly associated with time to RTP. Waviness was present in 17 (24.3%) injuries. Mean time to RTP for injuries without and with waviness was 22.6±7.5 and 30.2±10.8 days (p=0.014). There were 11 (15.7%) reinjuries within 12 months, five (17.2%) in the group with intramuscular tendon disruption and six (14.6%) in the group without intramuscular tendon disruption.

Conclusion

Time to RTP for injuries with full-thickness disruption of the intramuscular tendon and waviness is significantly longer (by slightly more than 1 week) compared with injuries without intramuscular tendon involvement. However, due to the considerable overlap in time to RTP between groups with and without intramuscular tendon involvement, its clinical significance for the individual athlete is limited.

Time for a paradigm shift in the classification of muscle injuries

Muscle injuries remain one of the most common injuries in sport, yet despite this, there is little consensus on how to either effectively describe or determine the prognosis of a specific muscle injury. Numerous approaches to muscle classification and grading of medicine have been applied over the last century, but over the last decade the limitations of historic approaches have been recognized. As a consequence, in the past 10 years, clinical research groups have begun to question the historic approaches and reconsider the way muscle injuries are classified and described. Using a narrative approach, this manuscript describes several of the most recent attempts to classify and grade muscle injuries and highlights the relative strengths and weaknesses of each system. While each of the new classification and grading systems have strengths, there remains little consensus on a system that is both comprehensive and evidence based. Few of the currently identified features within the grading systems have relevance to accurately determining prognosis.

Hamstring injuries: update article

Hamstring (HS) muscle injuries are the most common injury in sports. They are correlated to long rehabilitations and have a great tendency to recur. The HS consist of the long head of the biceps femoris, semitendinosus, and semimembranosus. The patient's clinical presentation depends on the characteristics of the lesion, which may vary from strain to avulsions of the proximal insertion. The most recognized risk factor is a previous injury. Magnetic resonance imaging is the method of choice for the injury diagnosis and classification. Many classification systems have been proposed; the current classifications aim to describe the injury and correlate it to the prognosis. The treatment is conservative, with the use of anti-inflammatory drugs in the acute phase followed by a muscle rehabilitation program. Proximal avulsions have shown better results with surgical repair. When the patient is pain free, shows recovery of strength and muscle flexibility, and can perform the sport's movements, he/she is able to return to play. Prevention programs based on eccentric strengthening of the muscles have been indicated both to prevent the initial injury as well as preventing recurrence.

Characteristics of acute groin injuries in the adductor muscles: A detailed MRI study in athletes

Acute adductor injuries account for the majority of acute groin injuries; however, little is known about specific injury characteristics, which could be important for the understanding of etiology and management of these injuries. The study aim was to describe acute adductor injuries in athletes using magnetic resonance imaging (MRI). Male athletes with acute groin pain and an MRI confirmed acute adductor muscle injury were prospectively included. MRI was performed within 7 days of injury using a standardized protocol and a reliable assessment approach. 156 athletes presented with acute groin pain of which 71 athletes were included, median age 27 years (range 18-37). There were 46 isolated muscle injuries and 25 athletes with multiple adductor injuries. In total, 111 acute adductor muscle injuries were recorded; 62 adductor longus, 18 adductor brevis, 17 pectineus, 9 obturator externus, 4 gracilis, and 1 adductor magnus injury. Adductor longus injuries occurred at three main injury locations; proximal insertion (26%), intramuscular musculo-tendinous junction (MTJ) of the proximal tendon (26%) and the MTJ of the distal tendon (37%). Intramuscular tendon injury was seen in one case. At the proximal insertion, 12 of 16 injuries were complete avulsions. This study shows that acute adductor injuries generally occur in isolation from other muscle groups. Adductor longus is the most frequently injured muscle in isolation and in combination with other adductor muscle injuries. Three characteristic adductor longus injury locations were observed on MRI, with avulsion injuries accounting for three-quarters of injuries at the proximal insertion, and intramuscular tendon injury was uncommon.

Magnetic resonance imaging for assessing hamstring injuries: clinical benefits and pitfalls - a review of the current literature

Hamstring injuries are common injuries in all levels of athletics. Hamstring injuries can cause prolonged absence from sports and have a notorious rate of reinjury. Magnetic resonance imaging (MRI) is being increasingly utilized following a hamstring injury. Physicians are being increasingly asked to utilize MRI to predict clinical outcomes, including time frame for return to play and risk of reinjury. In spite of numerous studies in this area, no clear consensus exists. The purpose of this paper is to summarize the literature and evidence regarding the role of MRI in treating hamstring injuries.

Subsequent Injuries Are More Common Than Injury Recurrences: An Analysis of 1 Season of Prospectively Collected Injuries in Professional Australian Football

BACKGROUND

It is known that some people can, and do, sustain >1 injury over a playing season. However, there is currently little high-quality epidemiological evidence about the risk of, and relationships between, multiple and subsequent injuries.

PURPOSE

To describe the subsequent injuries sustained by Australian Football League (AFL) players over 1 season, including their most common injury diagnoses.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Within-player linked injury data on all date-ordered match-loss injuries sustained by AFL players during 1 full season were obtained. The total number of injuries per player was determined, and in those with >1 injury, the Subsequent Injury Classification (SIC) model was used to code all subsequent injuries based on their Orchard Sports Injury Classification System (OSICS) codes and the dates of injury.

RESULTS

There were 860 newly recorded injuries in 543 players; 247 players (45.5%) sustained ≥1 subsequent injuries after an earlier injury, with 317 subsequent injuries (36.9% of all injuries) recorded overall. A subsequent injury generally occurred to a different body region and was therefore superficially unrelated to an index injury. However, 32.2% of all subsequent injuries were related to a previous injury in the same season. Hamstring injuries were the most common subsequent injury. The mean time between injuries decreased with an increasing number of subsequent injuries.

CONCLUSION

When relationships between injuries are taken into account, there is a high level of subsequent (and multiple) injuries leading to missed games in an elite athlete group.

'Serious thigh muscle strains': beware the intramuscular tendon which plays an important role in difficult hamstring and quadriceps muscle strains

Why do some hamstring and quadriceps strains take much longer to repair than others? Which injuries are more prone to recurrence? Intramuscular tendon injuries have received little attention as an element in 'muscle strain'. In thigh muscles, such as rectus femoris and biceps femoris, the attached tendon extends for a significant distance within the muscle belly. While the pathology of most muscle injures occurs at a musculotendinous junction, at first glance the athlete appears to report pain within a muscle belly. In addition to the musculotendinous injury being a site of pathology, the intramuscular tendon itself is occasionally injured. These injuries have a variety of appearances on MRIs. There is some evidence that these injuries require a prolonged rehabilitation time and may have higher recurrence rates. Therefore, it is important to recognise the tendon component of a thigh 'muscle strain'.