Sport Medicine Journal Club
complications were reported in 9 studies. They included wound infections, skin and tendon necrosis, sural nerve damage, decreased ankle motion, deep venous thrombosis, and pulmonary embolus. Nonsurgical treatment was associated with fewer complications than surgery (RD, 20.16; 95% CI, 20.03 to 20.30). Differences in range of motion (3 studies) favored surgical intervention, but were clinically unimportant. Calf circumference (3 studies), strength (measured variously in 6 studies), and functional outcomes (measured by different scales in 4 studies) did not differ between interventions. Conclusions: Rates of rerupture were similar among patients with acute Achilles tendon rupture who were treated surgically or nonsurgically when early range of motion was used as a cointervention. Rates of other complications (major and minor) were fewer after nonsurgical treatment.
Commentary During the last decade, understanding of the treatment of Achilles tendon injury has increased, and attention has been directed to the functional stimulus of healing tendons. Recommendations to treat this injury either operatively or nonoperatively have been introduced.1 The medical and rehabilitation communities continue to seek more information on the evolved management of this serious injury. In their rigorous meta-analysis of randomized trials, Soroceanu et al add to 2 previous meta-analyses of operative versus nonoperative treatment of Achilles tendon rupture by the inclusion of the most recent studies and of publications in languages other than English. Their review concludes that nonoperative and operative treatments of Achilles tendon rupture yield equivalent outcomes provided that early functional rehabilitation is used. The outcomes studied include risk of rerupture, calf strength, calf circumference, range of motion, return to work, functional outcomes, and overall rate of complications. Approximately 80% of the patients in each group were male and in most instances the injury occurred during sport. All patients had treatment initiated within 3 weeks of injury.
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The review’s pooled and subgroup analyses confirm that functional rehabilitation is a critical factor in equalizing the rate of rerupture for surgical and nonsurgical patients. Of potential interest to the sport medicine community are the findings that active plantar flexion was 1 degree less in patients treated nonsurgically, and that calf circumference and most measures of strength were comparable between the 2 groups, and comparable to the uninjured leg. Although it is recognized that Achilles tendon rupture typically occurs during athletic activity, this study and others do not address operative versus nonoperative treatment in higher performance athletes. Practical knowledge about the injury would be enhanced by information about actual compliance with rehabilitation protocols, the ideal characteristics of a functional brace, and by studies of a limited (younger) age group. Sport-specific strength is an additional important outcome measure; for example, rapid foot push-off is critical in court sports, sprinting, dance, speedskating, and jumping. Willits et al2 found that rapid plantar flexion (270 degrees per second) is favored after operative treatment. The characteristics of tendon healing and tendon length may have some bearing on the speed of plantar flexion. Confirmation of end-to-end apposition of the ruptured tendon was not mentioned in all of the studies included in the review by Soroceanu et al. Magnetic resonance imaging or ultrasound can be used to judge satisfactory tendon apposition in nonsurgical cases, whereas, during surgery, direct visualization of the tendon ends is possible. A tendon can be shortened intentionally or unintentionally during surgical procedures, but this can not occur to the same degree without surgery, although over lengthening can occur in either group. Practical measurement of physiologic Achilles tendon length has been described by Rosso et al3 and may be useful in future studies. Because there are several relevant endpoints in recovery from this injury, development of a decision-making algorithm would be helpful to determine which patients would benefit from operative or nonoperative management of Achilles tendon rupture.
Gwyneth deVries, MD, MSc Department of Orthopedic Surgery Horizon Health, Fredericton, New Brunswick, Canada
REFERENCES 1. Chiodo CP; the AAOS Work Group. The Diagnosis and treatment of acute Achilles tendon rupture. Guideline and Evidence Report. 1st ed. Rosemont, IL: American Academy of Orthopedic Surgeons; 2009. 2. Willits K, Amendola A, Bryant D, et al. Operative versus nonoperative treatment of acute Achilles tendon ruptures: a multicenter randomized trial using accelerated functional rehabilitation. J Bone Joint Surg Am. 2010;92:2767–2775. 3. Rosso C, Schuetz P, Polzer C, et al. Physiological Achilles tendon length and its relation to tibia length. Clin J Sport Med. 2012;22: 483–487.
What Are the Most Important Risk Factors for Hamstring Muscle Injury? This CJSM Journal Club contribution provides a commentary on the following article: Freckleton G, Pizzari T. Risk factors for hamstring muscle strain injury in sport: a systematic review and meta-analysis. Br J Sports Med. 2013;47:351–358.
Overview of Original Article Objective: To identify the intrinsic and extrinsic risk factors associated with sport-related hamstring muscle injuries. Data Sources: MEDLINE, the Cochrane Library of Systematic Reviews up to August 2011, and 6 other databases were searched using words related to the study objective. Google Scholar was used to track citations, and reference lists of included studies were scanned to find additional relevant studies. Study Selection: The selected prospective, full-text studies in humans, published in the English language, could include either first-time or recurrent hamstring muscle injuries that were sport-related. Discrete data for the hamstring injury outcome had to assess intrinsic or extrinsic risk factors. Tendon Source of funding for the original study: No external funding. Correspondence about the original article: Tania Pizzari, PhD, La Trobe University, Department of Physiotherapy, Bundoora, Mebourne, Victoria 3086, Australia ([email protected]).
Ó 2014 Lippincott Williams & Wilkins
Clin J Sport Med Volume 24, Number 2, March 2014
and avulsion injuries and nonspecific musculoskeletal injuries were excluded, as were intervention, retrospective, and cross-sectional studies and nonsystematic reviews. Of 1649 articles identified by the searches, 26 were included, plus a further 8 studies identified through citation tracking. Thus, 31 prospective studies and 3 reviews were selected. Data Extraction: Details of the participants, the injuries and diagnosis, the sport involved, the risk factors investigated, and the outcomes and follow-up were extracted by the authors, who both assessed the studies’ methods. For continuous data, standardised mean differences (SMD) and 95% confidence intervals (CI), were calculated. Metaanalysis was conducted where possible using a random effects model. Main Results: Hamstring injuries were investigated in 14 studies of Australian football, 10 studies of soccer, 5 studies of track and field, and 2 studies of rugby. The follow-up period varied between 3 weeks and 8 years. The study method scores ranged from 44% to 94%, with 12 studies not adjusting appropriately for confounding factors such as previous injury and age. Older age was associated with probability of injury in a metaanalysis of 7 studies (SMD, 2.5; 95% CI, 0.78-4.15) and in a separate analysis of 3 studies (odds ratio [OR], 2.46, 95% CI, 0.98-6.14). Meta-analyses of 8 studies, including 2952 athletes, found previous hamstring injury to be a risk factor for future injury (relative risk [RR], 2.68; 95% CI, 1.99-3.61 and OR, 4.06; 95% CI, 2.39-6.89). Body mass index, weight, and height were generally not associated with first or recurrent hamstring injuries. There was little evidence from 11 studies that the ratio of hamstring to quadriceps strength was a risk factor for hamstring injuries, whatever the speed and contraction type of the testing. In 4 studies, hamstring peak torque was not found to be a risk for hamstring injuries (SMD, 20.24; 95% CI, 20.85 to 0.37). However, in 4 studies, increased quadriceps peak torque did appear to be a risk factor for hamstring injuries (SMD, 0.43; 95% CI, 0.05-0.81). Factors such as strength asymmetries, limb dominance, playing position, flexibility and fitness were not consistently associated with hamstring injuries. Ó 2014 Lippincott Williams & Wilkins
Sport Medicine Journal Club
Conclusions: Among many risk factors that were investigated only older age, previous hamstring injury, and increased quadriceps peak torque were associated with an increased risk of sustaining a future sport-related hamstring strain injury.
Commentary Freckleton and Pizzari are to be commended for providing the sport medicine community with the most comprehensive literature search and syntheses to date of studies relating to risk factors for hamstring muscle injury. The topic is of interest to all sport medicine practitioners concerned with the management of this most common muscle injury in sport. The greatest strength—but also weakness—of the review by Freckleton and Pizzari is in the pooling of data. The strength is that statistical power is potentially increased by including more injuries (events) associated with the individual risk factors being investigated.1 However, the weakness of pooling data that appear to be unadjusted is that important interaction effects or confounders may be missed, as the authors mentioned as a limitation of their study. The identification of risk factors was considered a critical step in the 4-step sequence of injury prevention that was introduced by van Mechelen et al.2 The reason for this is that risk factors related to a specific injury should offer information on the underlying causes for the particular injury.1,2 Thus, information on risk factors may suggest strategies for future injury prevention.2 Although this idea is simple and appealing, the multifactorial nature of injuries in sports may sometimes interfere with this approach, especially in prospective risk factor studies in which important factors, known and/or unknown, are not taken into account.1 The present systematic review agrees with previous studies in identifying older age and previous hamstring muscle injuries as risk factors for subsequent hamstring muscle injury. The role of quadriceps and hamstring muscle strength seems less clear. Based on the investigators’ statistical analyses, increased
quadriceps strength is a risk factor for hamstring muscle injury, whereas hamstring weakness is not. Does this mean that injury prevention should focus on systematic quadriceps strength reduction (immobilization would be quite effective for this) in athletes at risk of hamstring muscle injury—instead of eccentric hamstring strengthening? Probably not, especially as eccentric hamstring strengthening has been shown to be an effective injury-preventative strategy.3 Although the van Mechelen model may be theoretically useful, in reality our understanding of risk factors may suffer from not taking the multifactorial nature of hamstring muscle injuries into account.1 Freckleton and Pizzari suggest that previous injury and age should be considered in a multivariate model when other risk factors are investigated. However, based upon their findings of increased peak quadriceps strength as a risk factor for hamstring muscle injury it may also be relevant to include this isolated variable in multivariate analyses, to investigate interaction or confounding effects. Future studies of potential risk factors for hamstring muscle injury should also include adjustment for individual athletic exposure hours,1 particularly focusing on match-play exposure in high-risk hamstring-injury sports such as football, because match-play is associated with higher rates of hamstring injuries than is similar time spent training.3 These factors have not been adequately accounted for in the current literature, which limits our present understanding of risk factors for hamstring muscle injury. Kristian Thorborg, M Sportsphysio, PhD Arthroscopic Centre Amager Copenhagen University Hospital Amager-Hvidovre, Copenhagen, Denmark
REFERENCES 1. Bahr R, Holme I. Risk factors for sports injuries— a methodological approach. Br J Sports Med. 2003;37:384–392. 2. van Mechelen W, Hlobil H, Kemper H. Incidence, severity, etiology and prevention of sports injuries—a review of concepts. Sports Med. 1992;14:82–99. 3. Thorborg K. Why hamstring eccentrics are hamstring essentials. Br J Sports Med. 2012; 46:463–465.
www.cjsportmed.com |
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complications were reported in 9 studies. They included wound infections, skin and tendon necrosis, sural nerve damage, decreased ankle motion, deep venous thrombosis, and pulmonary embolus. Nonsurgical treatment was associated with fewer complications than surgery (RD, 20.16; 95% CI, 20.03 to 20.30). Differences in range of motion (3 studies) favored surgical intervention, but were clinically unimportant. Calf circumference (3 studies), strength (measured variously in 6 studies), and functional outcomes (measured by different scales in 4 studies) did not differ between interventions. Conclusions: Rates of rerupture were similar among patients with acute Achilles tendon rupture who were treated surgically or nonsurgically when early range of motion was used as a cointervention. Rates of other complications (major and minor) were fewer after nonsurgical treatment.
Commentary During the last decade, understanding of the treatment of Achilles tendon injury has increased, and attention has been directed to the functional stimulus of healing tendons. Recommendations to treat this injury either operatively or nonoperatively have been introduced.1 The medical and rehabilitation communities continue to seek more information on the evolved management of this serious injury. In their rigorous meta-analysis of randomized trials, Soroceanu et al add to 2 previous meta-analyses of operative versus nonoperative treatment of Achilles tendon rupture by the inclusion of the most recent studies and of publications in languages other than English. Their review concludes that nonoperative and operative treatments of Achilles tendon rupture yield equivalent outcomes provided that early functional rehabilitation is used. The outcomes studied include risk of rerupture, calf strength, calf circumference, range of motion, return to work, functional outcomes, and overall rate of complications. Approximately 80% of the patients in each group were male and in most instances the injury occurred during sport. All patients had treatment initiated within 3 weeks of injury.
160
| www.cjsportmed.com
Clin J Sport Med Volume 24, Number 2, March 2014
The review’s pooled and subgroup analyses confirm that functional rehabilitation is a critical factor in equalizing the rate of rerupture for surgical and nonsurgical patients. Of potential interest to the sport medicine community are the findings that active plantar flexion was 1 degree less in patients treated nonsurgically, and that calf circumference and most measures of strength were comparable between the 2 groups, and comparable to the uninjured leg. Although it is recognized that Achilles tendon rupture typically occurs during athletic activity, this study and others do not address operative versus nonoperative treatment in higher performance athletes. Practical knowledge about the injury would be enhanced by information about actual compliance with rehabilitation protocols, the ideal characteristics of a functional brace, and by studies of a limited (younger) age group. Sport-specific strength is an additional important outcome measure; for example, rapid foot push-off is critical in court sports, sprinting, dance, speedskating, and jumping. Willits et al2 found that rapid plantar flexion (270 degrees per second) is favored after operative treatment. The characteristics of tendon healing and tendon length may have some bearing on the speed of plantar flexion. Confirmation of end-to-end apposition of the ruptured tendon was not mentioned in all of the studies included in the review by Soroceanu et al. Magnetic resonance imaging or ultrasound can be used to judge satisfactory tendon apposition in nonsurgical cases, whereas, during surgery, direct visualization of the tendon ends is possible. A tendon can be shortened intentionally or unintentionally during surgical procedures, but this can not occur to the same degree without surgery, although over lengthening can occur in either group. Practical measurement of physiologic Achilles tendon length has been described by Rosso et al3 and may be useful in future studies. Because there are several relevant endpoints in recovery from this injury, development of a decision-making algorithm would be helpful to determine which patients would benefit from operative or nonoperative management of Achilles tendon rupture.
Gwyneth deVries, MD, MSc Department of Orthopedic Surgery Horizon Health, Fredericton, New Brunswick, Canada
REFERENCES 1. Chiodo CP; the AAOS Work Group. The Diagnosis and treatment of acute Achilles tendon rupture. Guideline and Evidence Report. 1st ed. Rosemont, IL: American Academy of Orthopedic Surgeons; 2009. 2. Willits K, Amendola A, Bryant D, et al. Operative versus nonoperative treatment of acute Achilles tendon ruptures: a multicenter randomized trial using accelerated functional rehabilitation. J Bone Joint Surg Am. 2010;92:2767–2775. 3. Rosso C, Schuetz P, Polzer C, et al. Physiological Achilles tendon length and its relation to tibia length. Clin J Sport Med. 2012;22: 483–487.
What Are the Most Important Risk Factors for Hamstring Muscle Injury? This CJSM Journal Club contribution provides a commentary on the following article: Freckleton G, Pizzari T. Risk factors for hamstring muscle strain injury in sport: a systematic review and meta-analysis. Br J Sports Med. 2013;47:351–358.
Overview of Original Article Objective: To identify the intrinsic and extrinsic risk factors associated with sport-related hamstring muscle injuries. Data Sources: MEDLINE, the Cochrane Library of Systematic Reviews up to August 2011, and 6 other databases were searched using words related to the study objective. Google Scholar was used to track citations, and reference lists of included studies were scanned to find additional relevant studies. Study Selection: The selected prospective, full-text studies in humans, published in the English language, could include either first-time or recurrent hamstring muscle injuries that were sport-related. Discrete data for the hamstring injury outcome had to assess intrinsic or extrinsic risk factors. Tendon Source of funding for the original study: No external funding. Correspondence about the original article: Tania Pizzari, PhD, La Trobe University, Department of Physiotherapy, Bundoora, Mebourne, Victoria 3086, Australia ([email protected]).
Ó 2014 Lippincott Williams & Wilkins
Clin J Sport Med Volume 24, Number 2, March 2014
and avulsion injuries and nonspecific musculoskeletal injuries were excluded, as were intervention, retrospective, and cross-sectional studies and nonsystematic reviews. Of 1649 articles identified by the searches, 26 were included, plus a further 8 studies identified through citation tracking. Thus, 31 prospective studies and 3 reviews were selected. Data Extraction: Details of the participants, the injuries and diagnosis, the sport involved, the risk factors investigated, and the outcomes and follow-up were extracted by the authors, who both assessed the studies’ methods. For continuous data, standardised mean differences (SMD) and 95% confidence intervals (CI), were calculated. Metaanalysis was conducted where possible using a random effects model. Main Results: Hamstring injuries were investigated in 14 studies of Australian football, 10 studies of soccer, 5 studies of track and field, and 2 studies of rugby. The follow-up period varied between 3 weeks and 8 years. The study method scores ranged from 44% to 94%, with 12 studies not adjusting appropriately for confounding factors such as previous injury and age. Older age was associated with probability of injury in a metaanalysis of 7 studies (SMD, 2.5; 95% CI, 0.78-4.15) and in a separate analysis of 3 studies (odds ratio [OR], 2.46, 95% CI, 0.98-6.14). Meta-analyses of 8 studies, including 2952 athletes, found previous hamstring injury to be a risk factor for future injury (relative risk [RR], 2.68; 95% CI, 1.99-3.61 and OR, 4.06; 95% CI, 2.39-6.89). Body mass index, weight, and height were generally not associated with first or recurrent hamstring injuries. There was little evidence from 11 studies that the ratio of hamstring to quadriceps strength was a risk factor for hamstring injuries, whatever the speed and contraction type of the testing. In 4 studies, hamstring peak torque was not found to be a risk for hamstring injuries (SMD, 20.24; 95% CI, 20.85 to 0.37). However, in 4 studies, increased quadriceps peak torque did appear to be a risk factor for hamstring injuries (SMD, 0.43; 95% CI, 0.05-0.81). Factors such as strength asymmetries, limb dominance, playing position, flexibility and fitness were not consistently associated with hamstring injuries. Ó 2014 Lippincott Williams & Wilkins
Sport Medicine Journal Club
Conclusions: Among many risk factors that were investigated only older age, previous hamstring injury, and increased quadriceps peak torque were associated with an increased risk of sustaining a future sport-related hamstring strain injury.
Commentary Freckleton and Pizzari are to be commended for providing the sport medicine community with the most comprehensive literature search and syntheses to date of studies relating to risk factors for hamstring muscle injury. The topic is of interest to all sport medicine practitioners concerned with the management of this most common muscle injury in sport. The greatest strength—but also weakness—of the review by Freckleton and Pizzari is in the pooling of data. The strength is that statistical power is potentially increased by including more injuries (events) associated with the individual risk factors being investigated.1 However, the weakness of pooling data that appear to be unadjusted is that important interaction effects or confounders may be missed, as the authors mentioned as a limitation of their study. The identification of risk factors was considered a critical step in the 4-step sequence of injury prevention that was introduced by van Mechelen et al.2 The reason for this is that risk factors related to a specific injury should offer information on the underlying causes for the particular injury.1,2 Thus, information on risk factors may suggest strategies for future injury prevention.2 Although this idea is simple and appealing, the multifactorial nature of injuries in sports may sometimes interfere with this approach, especially in prospective risk factor studies in which important factors, known and/or unknown, are not taken into account.1 The present systematic review agrees with previous studies in identifying older age and previous hamstring muscle injuries as risk factors for subsequent hamstring muscle injury. The role of quadriceps and hamstring muscle strength seems less clear. Based on the investigators’ statistical analyses, increased
quadriceps strength is a risk factor for hamstring muscle injury, whereas hamstring weakness is not. Does this mean that injury prevention should focus on systematic quadriceps strength reduction (immobilization would be quite effective for this) in athletes at risk of hamstring muscle injury—instead of eccentric hamstring strengthening? Probably not, especially as eccentric hamstring strengthening has been shown to be an effective injury-preventative strategy.3 Although the van Mechelen model may be theoretically useful, in reality our understanding of risk factors may suffer from not taking the multifactorial nature of hamstring muscle injuries into account.1 Freckleton and Pizzari suggest that previous injury and age should be considered in a multivariate model when other risk factors are investigated. However, based upon their findings of increased peak quadriceps strength as a risk factor for hamstring muscle injury it may also be relevant to include this isolated variable in multivariate analyses, to investigate interaction or confounding effects. Future studies of potential risk factors for hamstring muscle injury should also include adjustment for individual athletic exposure hours,1 particularly focusing on match-play exposure in high-risk hamstring-injury sports such as football, because match-play is associated with higher rates of hamstring injuries than is similar time spent training.3 These factors have not been adequately accounted for in the current literature, which limits our present understanding of risk factors for hamstring muscle injury. Kristian Thorborg, M Sportsphysio, PhD Arthroscopic Centre Amager Copenhagen University Hospital Amager-Hvidovre, Copenhagen, Denmark
REFERENCES 1. Bahr R, Holme I. Risk factors for sports injuries— a methodological approach. Br J Sports Med. 2003;37:384–392. 2. van Mechelen W, Hlobil H, Kemper H. Incidence, severity, etiology and prevention of sports injuries—a review of concepts. Sports Med. 1992;14:82–99. 3. Thorborg K. Why hamstring eccentrics are hamstring essentials. Br J Sports Med. 2012; 46:463–465.
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