Importance Presently, acute surgical repair (within 4–6 weeks) of complete, proximal hamstring avulsion is the recommended treatment. No systematic review to date has evaluated patient satisfaction and return to sport after acute repair of complete, proximal hamstring avulsion injury.
Objective To systematically review the current evidence regarding management of complete, proximal hamstring avulsion injuries in relation to patient satisfaction and return to sport.
Evidence review PubMed, CINAHL, SPORTDiscus, EMBASE and Cochrane library were searched systematically for relevant studies through October 2015. Two authors independently screened the results and identified studies meeting inclusion criteria. Included studies were reviewed for patient satisfaction and return to sport outcomes, and their results are reported.
Findings A total of 22 studies (262 participants) were identified in this review. Only 4 studies, totalling 24 patients, reported on non-operative management, while 18 studies, totalling 238 patients, reported on operative management of complete, proximal hamstring avulsions. No identified study specifically measured patient satisfaction and return to sport in a prospective or case–controlled manner. Most studies were case reports with low level of evidence. Patient satisfaction after acute repair of complete, proximal hamstring avulsion ranged from 80% to 93% and return to sport was 94.5%. Non-operative management resulted in lower patient satisfaction (16.7%) and return to sport (54.2%).
Conclusions and relevance Acute surgical repair (within 4–6 weeks) of complete, proximal hamstring avulsion injuries results in high patient satisfaction and high level of return to preinjury sporting level, when compared to non-operative treatment. No conclusions regarding surgical repair of incomplete hamstring avulsion injuries or type of repair could be drawn from this review. More prospective data would be of value, as acute repair of complete, proximal hamstring avulsions appears to result in better outcomes than non-operative management, but any conclusion regarding comparison is limited due to the dearth of non-operative management studies and the high risk of bias.
Level of evidence Level IV.
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What we already know
Acute surgical repair of proximal hamstring avulsions when compared to non-operative management is technically easier than surgical management of injuries that were previously managed non-operatively.
Acute surgical repair of proximal hamstring avulsions when compared to non-operative management is currently recommended for treatment of avulsion injuries in high-level athletes.
Acute surgical management appears to result in better functional outcomes, but improvements in patient satisfaction and return to sport have not been established.
What are the new findings
Acute surgical repair of complete, proximal hamstring avulsion injuries results in high patient satisfaction, when compared to non-operative treatment.
Acute surgical repair of complete, proximal hamstring avulsion injuries results in high level of return to preinjury sporting level, when compared to non-operative treatment.
Acute surgical repair of complete, proximal hamstring avulsion injuries should be considered for all active individuals.
Proximal hamstring injuries are complex and pose a significant treatment dilemma. These injuries occur from forceful contraction of the hip with the knee in an extended position, placing the hamstring at its greatest length during contraction.1–3 Injuries of the proximal tendon can range from partial tears to complete rupture and should be differentiated from avulsion of the apophysis in the adolescent and muscle tears or proximal hamstring tendinopathy. In athletes, these injuries are most common in sports in which the hip is place in this position, for example, waterskiing, dancing, soccer and rugby.3–5
Recent studies6 ,7 and systematic reviews8 ,9 have trended towards recommending operative repair of hamstring avulsion injuries. However, many of these studies and reviews have not addressed the particular nature of the injury (complete vs incomplete), the acuity of surgical repair or the patient satisfaction and return to sport within the same study or review. This systematic review aims to specifically determine if acute surgical repair of complete, proximal hamstring avulsion injuries results in better patient satisfaction and return to sport when compared to non-operative treatment.
Search strategies were developed with the assistance of a health sciences librarian with expertise in searching for systematic reviews. Comprehensive search strategies, including index and keyword methods, were devised for the following databases: PubMed, CINAHL (EBSCO), EMBASE (Elsevier), SPORTDiscus (EBSCO) and Cochrane Central Register of Controlled Trials (Wiley). No database filters were used, in an effort to maximise sensitivity. Searches were conducted during October 2015, and results for each database can be found in the flow diagram (figure 1).
A total of 5166 references were identified using the aforementioned search strategy. After removal of duplicate references, a total of 3422 potentials records were identified for screening. References were included during the screening process if they were original articles that described treatment, either surgical or non-operative, of complete, proximal hamstring injuries in adult patients. Articles were excluded by the following criteria: (1) abstracts, comments, editorials or letters only, (2) non-English language publications, (3) animal studies, (4) technique papers, (5) imaging or anatomic papers, (6) review articles, (7) hamstring harvesting or autograft articles, (8) distal or midsubstance hamstring injuries, (8) muscle belly injuries, (9) muscle strains and (10) injuries in adolescent or paediatric patients. Owing to paucity or the literature in this area, case reports and case series were included in the screening process. After completion of the screening process, a total of 108 full-text articles were available for in-depth review.
Two reviewers (JB and RW) independently reviewed the 108 potential articles identified by the search strategy and screening process. Each reviewer completely reviewed each article and independently identified articles that met criteria for inclusion. Inclusion criteria for operative management included: complete, proximal hamstring injury, acute surgical intervention (<6 weeks from time of injury), adult patients (>18 years old or description of skeletal maturity), follow-up assessment at least 1 year from surgery and assessment of either patient satisfaction or return to sport. Inclusion criteria for non-operative management included: complete, proximal hamstring injury, description of non-operative treatment modality, adult patients (>18 years old or description of skeletal maturity), follow-up assessment at least 1 year from surgery and assessment of either patient satisfaction or return to sport. There was no disagreement between reviewers over included articles; however, a third reviewer (AA) was available if no consensus was reached on inclusion. Additionally, the bibliographies of each of the 108 selected articles were reviewed for articles that were not identified in the original search strategy; we identified an additional 18 additional articles, which were then reviewed using the same screening process as all other articles. After this review process, a total of 22 articles were identified for data analysis (figure 2).
Data from the selected 22 original articles was analysed by identifying the following information: number of patients, age of patients, follow-up period and patient outcomes and return to sport. In several instances, we were only able to analyse a subset of the patients presented in the original articles, due to individual patients not meeting inclusion criteria. Additionally, patients under the age of 18 years of age were excluded from analysis.
We identified 22 studies1–4 ,10–23 that met inclusion criteria (table 1). Outcomes data were available for a total of 262 patients with a mean age of 39.7 years; two studies1 ,14 included did not report the ages of the patients. Most studies were either retrospective case series or retrospective case reports; two retrospective reviews of prospectively collected case series were identified.24 ,25 Of the 22 studies, 17 studies2–4 ,10 ,11 ,13 ,14 ,16–18 ,20–25 reported on return to sport and of the 22 studies, 13 studies1–3 ,11–13 ,15 ,17–19 ,22 ,24 ,26 reported on patient satisfaction with 10 studies2 ,3 ,11–13 ,17–19 ,22 ,24 reporting on both outcomes. Four studies3 ,10 ,11 ,22 identified non-operative management of acute hamstring avulsions and 181 ,2 ,4 ,12–26 studies identified operative management of acute hamstring injuries, with 1 study22 detailing operative and non-operative management.
We identified only four studies3 ,10 ,11 ,22 that detailed a total of 24 patients who underwent non-operative management of complete, proximal hamstring ruptures. Of these four studies, follow-up ranged from 31 months to 7 years with 1 study not reporting follow-up. All four studies reported on return to sport with only 13 of 24 (54.2%) patients returned to preoperative sporting level after non-operative management with timing of return to sport not reported in any of the studies reviewed. Only 2 of these studies3 ,11 assessed patient satisfaction with 1 of 6 (16.7%) reporting a satisfactory outcome after non-operative management. Two patients reported later operative management secondary to dissatisfaction with non-operative management. Three studies3 ,10 ,22 reported on functional strength deficit and values ranged from 60 to 80% decreased strength of the injured hamstring complex when compared to the contralateral side.
We identified 18 studies1 ,2 ,4 ,12–26 that detailed a total of 238 patients who underwent operative management of complete, proximal hamstring ruptures. Of the 18 studies identified, 13 studies2 ,4 ,13 ,14 ,16–18 ,20–25 reported on return to sport. A total of 115 of the 123 patients (93.5%) returned to preoperative sporting level after operative management with timing of return to sport ranging from 6 months to 1 year. Only 11 of these studies1 ,2 ,12 ,13 ,15 ,17–19 ,22 ,24 ,26 assessed patient satisfaction with a 137 of 145 (94.5%) of patients reporting a satisfactory outcome after operative management. There was one reported failure, requiring additional surgical intervention. Six studies1 ,12 ,13 ,16 ,24 ,25 reported on functional strength deficit and values ranged from 81 to 93% decreased strength of the injured hamstring complex when compared to the contralateral side.
Waterskiing and rugby were to highest reported sporting activities. The sports identified in these studies were as follows: (70) waterskiing,4 ,19 ,24 ,26 (36) rugby,4 ,24 ,25 (19) soccer,4 ,20 ,23 (10) martial arts,4 ,21–24 ,26 (6) skiing,4 ,25 (3) running,4 (2) baseball,26 (2) football,25 (2) netball,4 (2) gymnastics,4 (2) lacrosse,4 (2) equestrian,4 (2) bull riding,14 (1) basketball,24 (1) softball,24 (1) track and field,4 (1) dance,4 (1) race walking26 and (1) hockey.4
The quality of included studies as assessed according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE)27–31 Working Group was found to be ‘low’ to ‘very low’ (table 1). All studies were initially categorised as ‘low’, given their observational, retrospective nature; no randomised trials were identified. Studies with imprecision or inconsistency of methodology, increased risk of bias or low patient numbers were assigned a ‘very low’ assessment nature. Studies generally consisted of level IV evidence, were retrospective in nature and performed as single institution case series. No studies were randomised or used control groups. Validated outcome measures were rarely used. Bias for each was assessed as incorporated into the GRADE assessment of quality score. Given the low patient numbers, low GRADE quality of the studies and disparity of non-operative studies, this systematic review is susceptible to publication biases of the reviewed studies.
This systematic review aimed to determine if acute surgical repair of complete, proximal hamstring tendon injuries results in better patient satisfaction and return to sport when compared to non-operative treatment. The low quality of published studies and dearth of non-operative cases reported in the literature is remarkable. Despite the rigorous methodology of this review, results from retrospective, uncontrolled case series and case reports offer no better than a suggestion that acute surgical repair yields favourable results. Nonetheless, the results of this review indicate that acute surgical repair results in better outcomes; specifically, higher patient satisfaction and more likely to return to sporting activity. This review also attempted to evaluate these findings in comparison to non-operative management. Non-operative management led to lower patient satisfaction and less successful return to sports. Overall, the findings of this study are consistent with previous studies and reviews that suggest that acute repair results in better outcomes when compared to non-operative management; however, controlled prospective studies with adequate sample sizes of non-operative and surgical groups are needed for a precise comparison.
The strength of this review is that it identifies improved return to sport and patient satisfaction with acute surgical management of complete, proximal hamstring injuries. It is important to differentiate this study from many other studies that have evaluated all proximal hamstring injuries, including muscle strains and tears and incomplete, proximal hamstring injuries. Although these injuries may also be treated surgically, the purpose of this review was to identify complete injuries only. It is clear from this study that complete injuries have the potential to result in worse outcomes if not addressed surgically within an acute time period.
Additionally, this study was designed to eliminate chronic or subacute cases from analysis as these types of injuries may alter the patient satisfaction and return to sport outcomes. Many studies have detailed the surgical difficulty of managing subacute and chronic injuries including more difficult dissection secondary to scar formation and increased risk of complication; including sciatic nerve injuries. Although complications were not directly assessed in this review, our study indicates that acute surgical management appears to offer excellent results.
Return to sport
Of the studies that reported on return to sport, our investigation identified 24 athletes managed non-operatively for acute hamstring avulsion, with only 13 (54.3%) of these athletes returning to their preoperative athletic level. In contrast, we identified 197 athletes managed with acute surgical intervention for proximal hamstring avulsions, and 94 (98.8%) of these athletes returned to their preoperative sporting level within 1 year of surgical intervention. Many studies have indicated that specific sports are susceptible to this type of injury due to the hyperflexion of the hip and full extension of the knee at time of injury, specifically waterskiing and rugby. However, the distribution of injuries reported is more likely to reporting biases as this injury was reported in nearly all sporting activities. The results of this study appear to indicate that acute surgical intervention for complete, proximal hamstring injuries in the athletic population is necessary for a reasonable expectation of return to sporting activities.
There are limitations to this study. After systematic review of the available studies that met the criteria for inclusion, the overall quality of studies as assessed by GRADE27 ,31 was determined to be low or very low. All studies reviewed were retrospective in nature and the highest level of evidence was level III with most studies being case reports or series, level IV or level V. This inherently weakens the strength of this review, as the quality of the studies reviewed was low. Additionally, there was very little standardisation of postoperative protocols, non-operative protocols, length of follow-up or use of standardised patient outcomes measures. Although systematic reviews can potentially limit biases created by lack of standardisation, each report and thus the review itself is potentially susceptible to patient selection bias. Finally, in the studies reviewed, not all studies reported potentially relevant data, such as age or length of follow-up, especially in the retrospective case reports. This lack of complete detail leaves this review open to potential reporting bias.
A complete, proximal hamstring rupture is a potentially devastating injury that may lead to significant dysfunction and inability to return to preinjury activity levels. Overall, our review indicates that acute surgical management of complete, proximal hamstring ruptures results in improved return to sporting activity and patient satisfaction. However, current studies are of too poor quality to answer specific research questions with specificity, and high-quality clinical trials are needed in order to provide definite treatment recommendations.
The authors acknowledge Jennifer DeBerg, MLS, librarian, Hardin Library for Health Sciences, University of Iowa, for assistance in database query and management during the systematic review process.
Investigation was performed at the University of Iowa.
Contributors All authors contributed substantially to the design, analysis and preparation of this manuscript. All authors reviewed, edited and approved the final draft of this manuscript.
Competing interests None declared.
Provenance and peer review Commissioned; externally peer reviewed.
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