Self-reported and performance-based functional outcomes after surgical repair of proximal hamstring avulsions

Validation of the Parisian Hamstring Avulsion Score (PHAS) in the Evaluation and Follow-up of Patients Operated for Proximal Hamstring Avulsion

BACKGROUND

No validated score is available for the prediction of return to sport (RTS) after proximal hamstring avulsion (PHA) surgery.

PURPOSE

To validate a new assessment tool for patients after PHA surgery: the Parisian Hamstring Avulsion Score (PHAS).

STUDY DESIGN

Cohort study (Diagnosis); Level of evidence, 3.

METHODS

All patients at our clinic who had surgery for PHA between January 2015 and March 2018 were included in this study. A suspected clinical diagnosis of PHA was confirmed by magnetic resonance imaging. PHA was repaired by surgical reinsertion with suture anchors. Minimum postoperative follow-up was 2 years, and the PHAS, University of California, Los Angeles (UCLA), score, and Tegner score were used. The PHAS is a patient-reported outcome measure, evaluating the effect of PHA injury with 9 items. It was validated by calculating its psychometric properties, and then correlation analysis was performed to determine the relationship between the PHAS, UCLA score, and Tegner score. Cutoff values for the prediction of RTS were determined.

RESULTS

A prospective case series study was performed. A total of 156 patients were included. Median age (first quartile; third quartile) was 54.2 years (44.7 years; 61.3 years), and the mean ± SD time of the final follow-up was 69 ± 11.6 months. Two years after surgery, 66.7% (n = 104) of patients were able to RTS. A strong correlation was noted between all 3 scores at 1 year postoperatively. Overall internal consistency was high, with a Cronbach alpha coefficient of 0.86. The intraclass correlation coefficient was 0.96, showing excellent reliability. The minimal detectable change was 12.9. No patients reached the maximum score at 2 years. Analysis of the receiver operating characteristic curves of the 3 scores at postoperative 9 months in relation to the RTS at 1 and 2 years showed area under the curve values of >0.7, indicating significant discriminant capacity for the RTS. A PHAS cutoff value of 86 at 9 months for the prediction of RTS at postoperative 1 year had a sensitivity of 65.6% (95% CI, 53.7%-77.5%) and a specificity of 81.4% (95% CI, 69.8%-93%).

CONCLUSION

PHAS is a valid and reliable tool for follow-up after PHA surgery. It also offers a simple way to predict RTS.

Systematic Review of Bracing After Proximal Hamstring Repair

Background

Traditionally, postoperative rehabilitation protocols after proximal hamstring repair (PHR) for avulsion of the proximal hamstring tendon from its ischial insertion recommend bracing the hip and/or knee to protect the fixation. However, because of the cumbersome nature of these orthoses, recent studies have investigated outcomes in patients with postoperative protocols that do not include any form of postoperative bracing.

Purpose

To synthesize the current body of evidence concerning bracing versus nonbracing postoperative management of PHR.

Study Design

Systematic review; level of evidence, 4.

Methods

Using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, we conducted a thorough search of the PubMed/Medline, Cochrane, CINAHL (Cumulative Index to Nursing and Allied Health Literature), and Embase (OVID) databases on March 24, 2023. We analyzed complication rates, reoperation rates, patient satisfaction, return to sport, and patient-reported outcomes of studies that used postoperative bracing versus studies that used no postoperative bracing after PHR with at least 12 months of follow-up. A total of 308 articles were identified after initial search.

Results

In total, 25 studies were included in this review: 18 studies (905 patients) on bracing and 7 studies (291 patients) on nonbracing after PHR. The overall complication rate in the braced patients was found to be 10.9%, compared with 12.7% in nonbraced patients. The rate of reoperation due to retear of the proximal hamstring was found to be 0.05% in braced patients and 3.1% in nonbraced patients. Patient-reported outcome measures were found to be higher at the final follow-up in braced versus nonbraced patients, and patient satisfaction was found to be 94.7% in braced studies compared with 88.9% in nonbraced studies. The rate of 12-month return to sport in athletic patients was 88.4% with bracing and 82.7% without bracing.

Conclusion

The findings of this review demonstrated lower complication and reoperation rates, higher patient-reported outcome scores, higher patient satisfaction, and a higher rate of return to sport in braced patients compared with nonbraced patients.

Development and application of a proximal hamstring MRI-based scoring tool in patients undergoing proximal hamstring tendon surgical repair

Purpose

An MRI-based scoring tool assessing surgical repair after proximal hamstring avulsions may provide benefit in the context of research, while serial post-operative MRI will provide insight of what to expect in the clinical context of early re-injury requiring imaging. This study developed and assessed the reliability of a Proximal Hamstring Objective Magnetic Resonance Imaging Score (PHOMRIS), further assessing MRI-based repair status and its correlation with patient-reported outcome.

Methods

15 patients that underwent proximal hamstring surgical repair underwent MRI and clinical review pre-operatively and at 3-, 6- and 12-months. Clinical scores included the Lower Extremity Functional Scale (LEFS), the Perth Hamstring Assessment Tool (PHAT) and Tegner Activity Scale (TAS). The MRI-based tool assessed the conjoint (semitendinosus & biceps femoris) and semimembranosus insertion components based on bone-tendon healing, signal and retraction. Inter- and intra-observer reliability of the tool was assessed.

Results

Inter-observer reliability indicated a strong correlation for the semimembranosus (rho = 0.827, p < 0.0001) and conjoint (rho = 0.851, p < 0.0001) components. Intra-observer reliability indicated a strong correlation for the semimembranosus (rho = 0.852, p < 0.0001) and conjoint (rho = 0.996, p < 0.0001) components. All clinical scores and the semimembranosus hamstrings component MRI score significantly improved (p < 0.05) over time, though the conjoint component did not (p = 0.219). At 12 months, a higher LEFS was significantly associated with a better semimembranosus MRI score (r = -0.57, p = 0.042), though no other significant correlations (p > 0.05) were observed between clinical and MRI measures.

Conclusions

Excellent reliability was observed for the MRI-based scoring tool, which may prove useful in both a research and clinical setting.

Systematic Review of Complications Associated With Proximal Hamstring Tendon Repair

Background

Although several complications of proximal hamstring tendon ruptures have been reported in the literature, few studies have comprehensively analyzed the complication profile of proximal hamstring tendon repair.

Purpose

To identify the overall rate of complications following proximal hamstring tendon repair and to differentiate these complications into categories.

Study Design

Systematic review; Level of evidence, 4.

Methods

Included in this review were studies that examined surgical repair of proximal hamstring tendon ruptures; all studies were in English and had an evidence level of 4 or higher. No restrictions were made regarding publication date or methodological quality. Data regarding complications were extracted to calculate the overall complication rate as well as the rate of major and minor complications. A quantitative data synthesis was conducted using the chi-square test to compare the proportion of patients who experienced complications with the endoscopic versus open approach.

Results

A total of 43 articles including 2833 proximal hamstring tendon repairs were identified. The overall postoperative complication rate was 15.3% (n = 433). The rate of major complications was 4.6%, including a 1.7% rate of sciatic nerve injury, 0.8% rate of venous thromboembolism, 0.8% reoperation rate, 0.8% rerupture rate, and 0.4% rate of deep infection. Minor complications included a 2.4% rate of posterior femoral cutaneous nerve injury, 2.3% rate of persistent hamstring myopathy, 2.2% rate of persistent sitting pain, 1.8% rate of peri-incisional numbness, 1.1% rate of superficial infection, and 0.8% rate of hematoma/seroma.

Conclusion

Proximal hamstring tendon repair is associated with an overall complication rate of 15.3%, including a 4.6% rate of major complications.

Do Outcomes Differ After Proximal Hamstring Repair for Patients Receiving Workers' Compensation?

Background

Patients with workers' compensation (WC) insurance claims are often shown to experience inferior patient-reported outcomes (PROs) after an orthopaedic surgical intervention compared with patients without WC claims.

Purpose

To compare the postoperative PROs of patients with WC claims (WC patients) versus those without WC claims (non-WC patients) after proximal hamstring repair (PHR).

Study Design

Cohort study; Level of evidence, 3.

Methods

WC patients who underwent PHR between November 2011 and to September 2020 were propensity score matched at a 1:2 ratio to non-WC patients according to age, sex, and body mass index. Comorbidity data were collected as well as minimum 1-year postoperative PRO scores for the Lower Extremity Functional Scale (LEFS), the Hip Outcome Score (HOS), and the 12-Item Short From Health Survey (SF-12) Physical Component Summary (PCS) and Mental Component Summary (MCS). The type of work was characterized according to national WC insurance guidelines as light (maximum 20 lbs [9.1 kg]), medium (maximum 50 lbs [22.7 kg]), or heavy (≥50 lbs) [>/=22.7 kg].

Results

A total of 30 patients (10 WC and 20 non-WC) were included. The work type and baseline demographic characteristics of patients did not differ between groups. There were no significant between-group differences in postoperative PRO scores as measured by the LEFS (P = .488), HOS (P = .233), or SF-12 PCS (P = .521). However, the WC cohort showed inferior SF-12 MCS scores compared with the non-WC group (49.28 ± 9.97 vs 54.26 ± 9.69, respectively; P = .032). The WC status was also associated with an increased time needed for patients to return to full-duty work capacity (21 ± 9 vs 9 ± 8 weeks; P = .005).

Conclusion

Our findings suggest that WC and non-WC patients who undergo PHR have comparable outcomes. Differences in SF-12 MCS scores and return to work time for full-duty capacity warrant further investigation.

At mid- to long-term follow-up after proximal hamstring tendon avulsion; there was greater fatty infiltration, muscle atrophy and strength deficit in the hamstring muscles of the injured leg than in the uninjured leg

BACKGROUND

Proximal hamstring tendon avulsions (PHAs) may be treated nonoperatively or operatively. Little is known about the result of the injury, and its treatment, on the quality and function of the hamstring muscle after healing and rehabilitation. We hypothesized that the injured leg would have greater fatty infiltration and atrophy than the uninjured leg at follow-up and that these findings would correlate to muscle weakness.

METHODS

In a cross-sectional cohort study, 48 patients treated for PHA, either operatively or nonoperatively, were re-examined 2-11 years post-treatment. We measured muscle strength with isokinetic strength tests, and muscle volume and fatty infiltration with MRI. Primary outcomes were hamstring muscle quality, quantified by outlining the cross-sectional area slice-by-slice, and the degree of fatty infiltration estimated using the Goutallier grading method. Secondary outcome was concentric isokinetic hamstring muscle strength measured using BioDex at 60°/sec and tendon attachment assessed on MRI. Comparisons with the outcomes of the uninjured leg were made.

RESULTS

The total hamstring muscle volume was on average reduced by 9% (SD ± 11%, p < 0.001) compared to that of the uninjured leg. Fatty infiltration was significantly more severe in the injured hamstrings than in the uninjured hamstrings (p < 0.001). This was also true when only analyzing operatively treated patients. The reduction in muscle volume and increase in fatty infiltration correlated significantly (r = 0.357, p = 0.013), and there was also a statistically significant correlation with muscle atrophy and reduction in isokinetic strength (r = 494, p < 0.001).

CONCLUSION

PHA injuries result in fatty infiltration and muscle atrophy and the muscle quality impairment correlates with residual muscle weakness.

The effect of theta burst stimulation over the primary motor cortex on experimental hamstring pain: A randomised, controlled study

Theta burst stimulation (TBS) over the primary motor cortex (M1) is an emerging technique that may have utility in the treatment of musculoskeletal pain. However, previous work exploring the analgesic effects of noninvasive brain stimulation has been limited largely to the arm or hand, despite 80% of acute musculoskeletal injuries occurring in the lower limb. This is a pertinent point, given the functional and neurophysiological differences between upper and lower limb musculature, as well as evidence suggesting that reorganization of corticomotor pathways is region-specific. This study investigated the effect of excitatory TBS on pain, function, and corticomotor organization during experimentally induced lower limb pain. Twenty-eight healthy participants attended 2 experimental sessions. On Day 0, participants completed 10 sets of 10 maximal eccentric contractions of the right hamstring muscles to induce delayed onset muscle soreness. Four consecutive blocks of either active or sham TBS were delivered on Day 2. Measures of mechanical sensitivity, pain (muscle soreness, pain intensity, pain area) function (single-leg hop distance, maximum voluntary isometric contraction, lower extremity functional scale), and corticomotor organization were recorded before and after TBS on Day 2. Pain and function were also assessed daily from Days 2 to 10. Active TBS reduced mechanical sensitivity compared to sham stimulation (P = .01). Corticomotor organization did not differ between groups, suggesting that improvements in mechanical sensitivity were not mediated by changes in M1. Subjective reports of pain intensity and function did not change following active TBS, contrasting previous reports in studies of the upper limb. PERSPECTIVE: M1 TBS reduces mechanical sensitivity associated with experimentally induced hamstring pain. Though further work is needed, these findings may hold important implications for those seeking to expedite recovery or reduce muscle sensitivity following hamstring injury.

A systematic review of surgical intervention in the treatment of hamstring tendon ruptures: current evidence on the impact on patient outcomes

Hamstring injuries are among the most common muscle injuries. They have been reported in many different sports, such as running, soccer, track and field, rugby, and waterskiing. However, they are also present among the general population. Most hamstring injuries are mild strains, but also moderate and severe injuries occur. Hamstring injuries usually occur in rapid movements involving eccentric demands of the posterior thigh. Sprinting has been found to mainly affect the isolated proximal biceps femoris, whereas stretching-type injuries most often involve an isolated proximal injury of the semimembranosus muscle. The main cause of severe 2- or 3-tendon avulsion is a rapid forceful hip flexion with the ipsilateral knee extended. Most hamstring injuries are treated non-surgically with good results. However, there are also clear indications for surgical treatment, such as severe 2- or 3-tendon avulsions. In athletes, more aggressive recommendations concerning surgical treatment can be found. For a professional athlete, a proximal isolated tendon avulsion with clear retraction should be treated operatively regardless of the injured tendon. Surgical treatment has been found to have good results in severe injuries, especially if the avulsion injury is repaired in acute phase. In chronic hamstring injuries and recurring ruptures, the anatomical apposition of the retracted muscles is more difficult to be achieved. This review article analyses the outcomes of surgical treatment of hamstring ruptures. The present study confirms the previous knowledge that surgical treatment of hamstring tendon injuries causes good results with high satisfaction rates, both in complete and partial avulsions. Early surgical repair leads to better functional results with lower complication rates, especially in complete avulsions.KEY MESSAGEsSurgical treatment of hamstring tendon ruptures leads to high satisfaction and return to sport rates.Both complete and partial hamstring tendon ruptures have better results after acute surgical repair, when compared to cases treated surgically later.Athletes with hamstring tendon ruptures should be treated more aggressively with operative methods.

Comparative Analysis of Patient-Reported Outcome Measures for Proximal Hamstring Injuries: A Systematic Review

Background

There is controversy regarding which patient-reported outcome measures (PROMs) should be used for proximal hamstring tendon injuries.

Hypothesis

It was hypothesized that (1) most (>50%) of the questions on the 13 most common PROMs for proximal hamstring injuries would demonstrate extensive overlap in the health domains and question categories and (2) each of the PROMs would contain a variable distribution of questions within each health domain.

Study Design

Systematic review.

Methods

We conducted a literature review through PubMed, Scopus, and CINAHL and identified the 13 most common PROMs for proximal hamstring injuries: Lower Extremity Functional Scale (LEFS), Marx activity rating scale (MARS), 12-item Short Form Survey (SF-12), Tegner activity scale (TAS), Single Assessment Numeric Evaluation (SANE), Perth Hamstring Assessment Tool (PHAT), Proximal Hamstring Injury Questionnaire (PHIQ), modified Harris Hip Score (mHHS), University of California, Los Angeles activity score (UCLA), International Hip Outcome Tool (iHOT-12), Hip Outcome Score (HOS), Sydney Hamstring Origin Rupture Evaluation (SHORE), and Non-Arthritic Hip Score (NAHS). All PROM questions were sorted into 5 health domains (pain, symptoms, activities of daily living, sports, and mindset) and further divided into question categories if they referred to similar tasks or aspects of health. Questions in the same health domain and question category were considered overlapping, and those within a health domain that did not fit into a question category were considered unique. For each PROM, we analyzed the distribution of questions within particular health domains and question categories as well as the amount of overlapping and unique questions.

Results

Of the 165 questions evaluated, 116 (70.3%) were overlapping, and 49 (29.7%) were unique. The SF-12 contained the most unique questions (9/12 [75.0%]). The MARS, TAS, SANE, and UCLA had 0 unique questions. The PHIQ and iHOT-12 contained questions in all 5 health domains. The PHAT, SHORE, and NAHS contained questions in every health domain except mindset. The LEFS, MARS, SF-12, TAS, mHHS, SANE, UCLA, and HOS contained questions in ≤3 health domains.

Conclusion

The evaluated PROMs had a high degree of overlapping questions (≥50%) and demonstrated a statistically significant variance in the distribution of questions within each health domain.

Outcomes following surgical management of proximal hamstring tendon avulsions

Aims

Avulsion of the proximal hamstring tendon origin can result in significant functional impairment, with surgical re-attachment of the tendons becoming an increasingly recognized treatment. The aim of this study was to assess the outcomes of surgical management of proximal hamstring tendon avulsions, and to compare the results between acute and chronic repairs, as well as between partial and complete injuries.

Methods

PubMed, CINAHL, SPORTdiscuss, Cochrane Library, EMBASE, and Web of Science were searched. Studies were screened and quality assessed.

Results

In all, 35 studies (1,530 surgically-repaired hamstrings) were included. Mean age at time of repair was 44.7 years (12 to 78). A total of 846 tears were acute, and 684 were chronic, with 520 tears being defined as partial, and 916 as complete. Overall, 92.6% of patients were satisfied with the outcome of their surgery. Mean Lower Extremity Functional Score was 74.7, and was significantly higher in the partial injury group. Mean postoperative hamstring strength was 87.0% of the uninjured limb, and was higher in the partial group. The return to sport (RTS) rate was 84.5%, averaging at a return of 6.5 months. RTS was quicker in the acute group. Re-rupture rate was 1.2% overall, and was lower in the acute group. Sciatic nerve dysfunction rate was 3.5% overall, and lower in the acute group (p < 0.05 in all cases).

Conclusion

Surgical treatment results in high satisfaction rates, with good functional outcomes, restoration of muscle strength, and RTS. Partial injuries could expect a higher functional outcome and muscle strength return. Acute repairs result in a quicker RTS with a reduced rate of re-rupture and sciatic nerve dysfunction. Cite this article: Bone Jt Open 2022;3(5):415–422.

Evidence-Based Management and Factors Associated With Return to Play After Acute Hamstring Injury in Athletes: A Systematic Review

Background:

Considering the lengthy recovery and high recurrence risk after a hamstring injury, effective rehabilitation and accurate prognosis are fundamental to timely and safe return to play (RTP) for athletes.

Purpose:

To analyze methods of rehabilitation for acute proximal and muscular hamstring injuries and summarize prognostic factors associated with RTP.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

In August 2020, MEDLINE, CINAHL, Cochrane Central Register of Controlled Trials, and SPORTDiscus were queried for studies examining management and factors affecting RTP after acute hamstring injury. Included were randomized controlled trials, cohort studies, case-control studies, and case series appraising treatment effects on RTP, reinjury rate, strength, flexibility, hamstrings-to-quadriceps ratio, or functional assessment, as well as studies associating clinical and magnetic resonance imaging factors with RTP. Risk of bias was assessed using the Cochrane Risk-of-Bias Tool for Randomized Trials or the Methodological Index for Non-Randomized Studies (MINORS).

Results:

Of 1289 identified articles, 75 were included. The comparative and noncomparative studies earned MINORS scores of 18.8 ± 1.3 and 11.4 ± 3.4, respectively, and 12 of the 17 randomized controlled trials exhibited low risk of bias. Collectively, studies of muscular injury included younger patients and a greater proportion of male athletes compared with studies of proximal injury. Surgery for proximal hamstring ruptures achieved superior outcomes to nonoperative treatment, whereas physiotherapy incorporating eccentric training, progressive agility, and trunk stabilization restored function and hastened RTP after muscular injuries. Platelet-rich plasma injection for muscular injury yielded inconsistent results. The following initial clinical findings were associated with delayed RTP: greater passive knee extension of the uninjured leg, greater knee extension peak torque angle, biceps femoris injury, greater pain at injury and initial examination, “popping” sound, bruising, and pain on resisted knee flexion. Imaging factors associated with delayed RTP included magnetic resonance imaging-positive injury, longer lesion relative to patient height, greater muscle/tendon involvement, complete central tendon or myotendinous junction rupture, and greater number of muscles injured.

Conclusion:

Surgery enabled earlier RTP and improved strength and flexibility for proximal hamstring injuries, while muscular injuries were effectively managed nonoperatively. Rehabilitation and athlete expectations may be managed by considering several suitable prognostic factors derived from initial clinical and imaging examination.

Achievement of the minimal clinically important difference following open proximal hamstring repair

There is a paucity of literature on patient-reported outcome measures (PROMs) following proximal hamstring repair beyond return to play, patient satisfaction and pain improvement. The minimal clinically important difference (MCID) defines the minimum degree of quantifiable improvement that a patient can perceive, but the MCID and predictors of this measure have not been defined for this patient population. This study aimed to define the MCID and determine the efficacy of open proximal hamstring repair through achievement of MCID and identify characteristics predictive of achieving MCID. A retrospective cohort review of an institutional hip registry was conducted, analyzing the modified Harris Hip Score (mHHS) and International Hip Outcome Tool (iHOT-33). MCID was calculated using a distribution-based method. Demographic and clinical variables predictive of achieving MCID were analyzed using univariable and multivariate logistic regression analyses. Thirty-nine patients who underwent open proximal hamstring repair were included. The mean patient age was 48.5 ± 12.4 years, with a mean follow-up of 37.1 ± 28 months. The MCID was determined for each PROM (mHHS—11.8; iHOT-33—12.6). A high percentage of patients achieved MCID for both PROMs (mHHS—85.7%; iHOT-33—91.4%). Univariate logistical regression demonstrated increased age (P = 0.163), increased body mass index (BMI; P = 0.072), requirement for inpatient admission (P = 0.088) and pre-operative iHOT-33 (P = 0.104) trended towards clinically significant predictors of not achieving MCID. A high percentage of patients achieved MCID while age, BMI, inpatient admission and pre-operative iHOT-33 appear to influence the achievement of clinically significant outcome in patients undergoing open proximal hamstring repair.

Delayed proximal hamstring tendon repair after ischial tuberosity apophyseal fracture in a professional volleyball athlete: a case report

Background

Ischial tuberosity apophyseal fractures are avulsion fractures of the anatomic footprint of the proximal hamstring tendons. Generally, these injuries are rare and frequently occur in skeletally immature, active patients due to incomplete ossification. Depending on the fragment displacement, non-operative or operative treatment approaches are used.

Case presentation

We report a case of a 29-year-old professional volleyball athlete who has suffered from a nonunion avulsion fracture for 14 years. Isolated suture anchor fixation was performed after open excision of a large bony fragment followed by excellent clinical and functional outcome at 1 year postoperatively.

Conclusion

In conclusion, avulsion fractures of the ischial tuberosity with large fragments and restrictions to activities of daily living due to pain can, in individualized cases, be treated with an open excision of the fragment followed by repair of the proximal hamstring tendons using suture anchors.

[Clinical results after refixation of proximal hamstring tendon ruptures comparing different anchor systems]

BACKGROUND

Injuries to the hamstring muscles and tendon complex are among the most frequent muscular injuries with proximal hamstring tendon avulsion being a particularly severe form. The surgical treatment of these injuries is superior to conservative management with respect to patient satisfaction, recovery of muscle strength and function as well as return to sport rates. It is therefore the method of choice.

OBJECTIVE

Presentation and comparison of the surgical results after treatment with titanium, polyether ether ketone (PEEK) and all suture anchors.

MATERIAL AND METHODS

A systematic search was carried out in the PubMed medical database and the results are summarized.

RESULTS

All systems exhibit comparable biomechanical properties regarding elongation and ultimate failure load. Tendon repair with these anchors results in good to excellent clinical outcomes and shows high return to sport and low complication rates. Patient satisfaction after hamstring tendon repair is reported to be over 90% and return to sport rate is 80-100%. The muscle strength recovers to 80-90% in comparison to the contralateral side.

CONCLUSION

All available anchors systems provide good to excellent clinical outcomes and an explicit advantage for one anchor system could so far not be shown.

Exploring the Perth Hamstring Assessment Tool and Lower Extremity Functional Scale in a Proximal Hamstring Avulsion Cohort: A Cross-sectional Study

BACKGROUND

The goal of treatment for a proximal hamstring avulsion (PHA) is an objectively restored muscle and a subjectively satisfied, pain-free patient at follow-up. Different self-reported and performance-based outcome measures have been used to evaluate recovery, but their validity is poorly investigated.

PURPOSE

To investigate (1) the correlation between the commonly used self-reported outcome measurements, the Perth Hamstring Assessment Tool (PHAT) and the Lower Extremity Functional Scale (LEFS); (2) to what extent these scores can be explained by physical dysfunction as measured by performance-based tests; (3) whether performance-based tests can discriminate between the injured and uninjured extremity; and (4) which activity limitations are perceived by patients several years after the injury.

STUDY DESIGN

Cohort study (Diagnosis); Level of evidence, 3.

METHODS

We included a consecutive series of patients treated for or diagnosed with PHA in our department between 2007 and 2016 having at least 2 tendons avulsed from the ischial tuberosity. Participants attended 2 study visits, answered questionnaires (PHAT, LEFS, and Patient-Specific Functional Scale [PSFS]), and performed physical performance-based tests (single-leg hop tests, single-step down test, and isometric and isokinetic strength tests).

RESULTS

A total of 50 patients were included (26 men [52%], 24 women [48%]; mean age, 50.9 years [SD, 9.8 years]). The mean follow-up time was 5.5 years (SD, 2.7 years), and 74% had been surgically treated. The correlation between PHAT and LEFS was strong (r = 0.832) and statistically significant (P < .001). Seven of the performance-based tests exhibited a statistically significant but weak correlation with LEFS (0.340-0.488) and 3 of the tests to PHAT (-0.304 to 0.406). However, only peak torque could significantly discriminate between the extremities. The activity limitation most commonly mentioned in PSFS was running (16 patients [32%]).

CONCLUSION

Although PHAT and LEFS correlated strongly, the correlations between functional tests and the patient-reported outcome scores were weak, and most functional tests failed to discriminate between the injured and uninjured lower extremity in patients with PHA 5 years after injury. In general, patients alleged few activity limitations, but running difficulty was a common sequela after PHA.

Systematic Review of Outcome Measures Used After Proximal Hamstring Repair

Background:

Patient-reported outcome measures are important to determine outcomes after orthopaedic procedures. There is currently no standard for outcome measures in the evaluation of patient outcomes after proximal hamstring repair.

Purpose:

To identify and evaluate outcome measures used after proximal hamstring repair.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A systematic review was performed to identify all English-language articles assessing outcomes after proximal hamstring repair in PubMed, Embase, CINAHL via EBSCOhost, MEDLINE via OvidSP, and Web of Science between 2000 and 2019. After duplicates were removed, studies were selected using eligibility criteria established by the authors. Image reviews, anatomic/histology studies, literature reviews, surgical technique reports, systematic reviews, narrative reviews, case studies, and studies with <5 patients were excluded. Extraction, synthesis, and analysis of outcome measure data were performed using Microsoft Excel. Quality assessment of included studies was performed using Methodological Index for Non-Randomized Studies criteria.

Results:

After duplicate articles were removed, a total of 304 unique articles were identified and 27 met the inclusion criteria. The mean number of patients with proximal hamstring repairs per study was 40. The most frequently reported outcome measures were return to sport (14/27; 51.9%), custom survey/questionnaire (13/27; 48.1%), and isokinetic hamstring strength testing (13/27; 48.1%). Six of the 10 most commonly used outcome measures were validated and included Lower Extremity Functional Scale, 12-Item Short Form Health Survey, visual analog scale for pain, Perth Hamstring Assessment Tool (PHAT), Single Assessment Numeric Evaluation, and Tegner Activity Scale. Of those, PHAT was the only validated outcome measure designed for proximal hamstring repair.

Conclusion:

There is currently no consensus on the best outcome measurements for the evaluation of patients after proximal hamstring repair. We recommend an increased commitment to the use of return to sport, isokinetic strength testing, Lower Extremity Functional Scale, and PHAT when assessing such injuries. Future studies should aim to define the most reliable methods of outcome measurement in this patient population through consistent use of tools that are clinically relevant and important to patients and can easily be employed in a variety of clinical scenarios.

Outcomes of Open and Endoscopic Repairs of Chronic Partial- and Full-Thickness Proximal Hamstring Tendon Tears: A Multicenter Study With Minimum 2-Year Follow-up

BACKGROUND

The preponderance of literature on the repair of proximal hamstring tendon tears focuses on the acute phase (<4 weeks). As such, there is a paucity of data reporting on the outcomes of chronic proximal hamstring tears.

PURPOSE

To report minimum 2-year postoperative patient-reported outcome (PRO) scores, visual analog scale (VAS) for pain, and patient satisfaction from patients who underwent open or endoscopic repair of partial- and full-thickness chronic proximal hamstring tendon tears.

STUDY DESIGN

Case series study; Level of evidence, 4.

METHODS

Between April 2002 and May 2017, prospectively collected data from 3 tertiary care institutions were retrospectively reviewed for patients who underwent open and endoscopic repair of partial- and full-thickness chronic proximal hamstring tendon tears. Patients were included only if they had a chronic proximal hamstring tear (defined as ≥4 weeks from symptom onset to surgery). Patients were excluded if they had a tear treated <4 weeks after injury, underwent hamstring reconstruction, or claimed workers' compensation. Patients who reported minimum 2-year follow-up for VAS, patient satisfaction, and the following PROs had their outcomes analyzed: the modified Hip Harris Score, Non-arthritic Hip Score, iHOT-12 (International Hip Outcome Tool), and Hip Outcome Score-Sports Specific Subscale.

RESULTS

Fifty patients (34 females and 16 males) were included in this study. There were 19 endoscopic repairs and 31 open repairs. Within the cohort, 52.0% had a full-thickness tendon tear on magnetic resonance imaging, and 48.0% had a partial tear. Average follow-up time was 58.07 ± 37.27 months (mean ± SD; range, 24-220 months). The mean age and body mass index of the group were 46.13 ± 13 years and 25.43 ± 5.14. The average time from injury to surgery was 66.73 weeks (range, 5.14-215.14 weeks). Average postoperative PROs were as follows: modified Hip Harris Score, 91.94 ± 9.96; Non-arthritic Hip Score, 91.33 ± 9.99; iHOT-12, 87.17 ± 17.54; Hip Outcome Score-Sports Specific Subscale, 87.15 ± 18.10; and VAS, 1.16 ± 1.92. Patient satisfaction was 8.22 ± 1.20.

CONCLUSION

Patients who underwent open and endoscopic repairs for chronic partial- and full-thickness proximal hamstring tendon tears reported high PROs and satisfaction at a minimum 2-year follow-up with low rates of complications.

Return to Sport After Surgical Management of Proximal Hamstring Avulsions: A Systematic Review and Meta-analysis

OBJECTIVE

To assess the rates and timing of return to sport for the surgical management of proximal hamstring avulsions (PHAs).

METHODS

Three databases, PubMed, MEDLINE, and EMBASE, were searched from database inception until October 7, 2017, by 2 reviewers independently and in duplicate. The inclusion criteria were studies reporting return to sport outcomes for surgical management of acute, chronic, complete, and partial PHA. The rate of return to sports was combined in a meta-analysis of proportions using a random-effects model.

RESULTS

Overall, 21 studies with a total of 846 patients met the inclusion criteria, with a mean age of 41.4 years (range, 14-71 years) and a mean follow-up of 37.8 months (range, 6-76 months). Two studies were of prospective comparative design (level II), 2 were retrospective comparative (level III), 8 were prospective case series (level IV), and 9 were retrospective case series (level IV). The overall mean time to return to sport was 5.8 months (range, 1-36 months). The pooled rate of return to any sport participation was 87% [95% confidence interval (CI), 77%-95%]. The pooled rate of return to preinjury level of sport was 77% (95% CI, 66%-86%).

CONCLUSIONS

Pooled results suggest a high rate of return to sport after surgical management of PHA; however, this was associated with a lower preinjury level of sport. No major differences in return to sport were found between partial versus complete and acute versus chronic PHA.

Does Time From Injury to Surgery Affect Outcomes After Surgical Repair of Partial and Complete Proximal Hamstring Ruptures?

Background

No previous study has compared the outcomes of repair for partial and complete proximal hamstring ruptures at various intervals after the injury.

Purpose

The primary aim was to determine whether time from injury to surgery affected outcomes after primary repair of partial and complete proximal hamstring ruptures. The secondary aim was to assess patients' experiences from initial evaluation to finding a treating surgeon.

Study Design

Cohort study; Level of evidence, 3.

Methods

Records from 2007 to 2016 from a single surgeon's practice were reviewed. A total of 124 proximal hamstring repair procedures in 121 patients were identified. There were 92 patients who completed questionnaires: a custom survey, the standard Lower Extremity Functional Scale (LEFS), a custom LEFS, the standard Marx activity scale, a custom Marx activity scale, and the University of California Los Angeles (UCLA) activity score. Results were analyzed for partial and complete repair procedures performed at ≤3 weeks, ≤6 weeks, and >6 weeks after the injury.

Results

The mean follow-up was 43 months (median, 38 months). Of 93 repair procedures reviewed, 51% (9/28 partial; 38/65 complete), 79% (16/28 partial; 57/65 complete), and 22% (12/28 partial; 8/65 complete) were performed at ≤3 weeks, ≤6 weeks, and >6 weeks, respectively. At those various intervals, no statistical difference was found in standard LEFS, custom LEFS, standard Marx, custom Marx, or UCLA scores. Female sex, older age, and body mass index >30 kg/m² were negative predictors of outcome measures. When repaired >6 weeks after the injury, a greater percentage of patients reported weakness of the operative leg compared with the contralateral side (partial tears: 6.3% vs 25%, respectively; complete tears: 24.6% vs 50%, respectively) in addition to greater sitting intolerance (partial tears: 0% vs 25%, respectively; complete tears: 7.1% vs 12.5%, respectively). Patients repaired >6 weeks after the injury visited, on average, 2.6 practitioners before an evaluation by the treating surgeon compared with 1.6 treated surgically at ≤6 weeks (P = .008).

Conclusion

Patients with proximal hamstring repair performed in the acute and chronic settings can expect successful outcomes but may experience more subjective weakness and difficulty with prolonged sitting when the repair is performed >6 weeks after the injury. Patients faced challenges in receiving the correct diagnosis and referral to an appropriate treating surgeon, emphasizing the need for an increased awareness of the injury.

Musculotendinous Junction Injuries of the Proximal Biceps Femoris: A Prospective Study of 64 Patients Treated Surgically

BACKGROUND

Injuries to the hamstring complex most commonly involve the proximal musculotendinous junction of the long head of the biceps femoris (MTJ-BFlh). Nonoperative management of these injuries is associated with prolonged rehabilitation and high risk of recurrence. To our knowledge, the surgical management of acute MTJ-BFlh injuries has not been previously reported.

HYPOTHESIS

Surgical repair of acute MTJ-BFlh injuries enables return to sporting activity with low risk of recurrence.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 64 patients (42 male and 22 female) undergoing surgical repair of acute MTJ-BFlh injuries were included. Predefined outcomes were recorded at regular intervals after surgery. Mean follow-up time after surgery was 29.2 months (range, 24.0-37.1 months).

RESULTS

All study patients returned to their preinjury levels of sporting activity. Mean ± SD time from surgical intervention to return to sporting activity was 13.4 ± 5.1 weeks. Three patients had reinjury at the operative site: 1 (1.6%) with MTJ-BFlh injury and 2 (3.2%) with myofascial tears. At 3 months after surgery, patients had improved mean passive straight-leg raise (72.0° ± 11.4° vs 24.1° ± 6.8°; P < .001); increased mean isometric hamstring muscle strength at 0° (84.5 % ± 10.4% vs 25.9% ± 8.9%; P < .001), 15° (89.5% ± 7.3% vs 41.2% ± 9.7%; P < .001), and 45° (93.9% ± 5.1% vs 63.4% ± 7.6%; P < .001); higher mean Lower Extremity Functional Scale scores (71.5 ± 5.0 vs 29.8 ± 6.3; P < .001); and improved mean Marx activity rating scores (9.8 ± 2.2 vs 3.8 ± 1.9; P < .001), as compared with preoperative scores. High patient satisfaction and functional outcome scores were maintained at 1 and 2 years after surgery.

CONCLUSION

Surgical repair of acute MTJ-BFlh injuries enables return to preinjury level of sporting function with low risk of recurrence at short-term follow-up.

Implementing Patient-Reported Outcome Measures in Outpatient Rehabilitation Settings: A Systematic Review of Facilitators and Barriers Using the Consolidated Framework for Implementation Research

OBJECTIVE

This systematic review examines the facilitators and barriers to the use of patient-reported outcome measures (PROMs) in outpatient rehabilitation settings and provides strategies to improve care to maximize patient outcomes.

DATA SOURCES

Eleven databases were systematically searched from November 2018 to May 2019.

STUDY SELECTION

Two reviewers independently assessed articles based on the following inclusion criteria: English text, evaluate barriers and facilitators, include PROMs, and occur in an outpatient rehabilitation setting (physical therapy, occupational therapy, speech language pathology, or athletic training). Of the 10,164 articles initially screened, 15 articles were included in this study.

DATA EXTRACTION

Data were extracted from the selected articles by 2 independent reviewers and put into an extraction template and into the Consolidated Framework for Implementation Research (CFIR) model. The Appraisal Tool for Cross-Sectional Studies (AXIS) was conducted on each study to assess study design, risk of bias, and reporting quality of the eligible studies.

DATA SYNTHESIS

Ten studies were identified as high quality, according to the AXIS. Based on the CFIR model, the top barriers identified focused on clinician training and time in the implementation process, lack of recognized value and knowledge at the individual level, lack of access and support in the inner setting, and inability of patients to complete PROMs in the intervention process. Facilitators were identified as education in the implementation process, support and availability of PROMs in the inner setting, and recognized value at the individual level.

CONCLUSIONS

More barriers than facilitators have been identified, which is consistent with PROM underuse. Clinicians and administrators should find opportunities to overcome the barriers identified and leverage the facilitators to improve routine PROM use and maximize patient outcomes.

Short-Term Outcomes Following Endoscopic Proximal Hamstring Repair

PURPOSE

The purpose of this study was to evaluate the outcomes of endoscopic proximal hamstring repair (ePHR), specifically: (1) functional and subjective outcomes, (2) effectiveness of treatment (preoperative-to-postoperative change), (3) complications, (4) acute versus chronic tears, and (5) partial versus complete tears.

METHODS

A retrospective case series of a single-surgeon database for all patients who underwent ePHR between November 2014 and January 2019 with a minimum 1-year follow-up (range, 12 to 48 months) was performed. Charts were analyzed for preoperative and postoperative passive range of motion (PROM), strength, VAS pain, UCLA activity, and modified Harris Hip Score (mHHS). Manual muscle strength testing based on standard grading scale of 0 to 5 was performed. Complications including re-tear of the repair site, infection, iatrogenic nerve injury, inability to return to work/sport at the same level as preinjury, persistent hamstring weakness, pain with sitting, and subsequent surgery were recorded.

RESULTS

We identified 20 ePHR (6 males, 14 females) with a mean age of 46 years (range, 18 to 63 years). At most recent follow-up, mean VAS pain was 1.85 (SD 2), UCLA activity was 8 (SD 2), mHHS was 90.6 (SD 10.5), and PROM hip flexion of 121.7° (SD 14.5°). Effectiveness of treatment demonstrated significant improvement in objective hamstring strength, hip flexion PROM by 17.3°, UCLA activity by 3, and VAS pain by 3 points. Subjective hamstring weakness was reported in 8 (42.1%) and persistent pain with sitting in 3 (15.8%). Return to work and sport were 100% and 95%, respectively. mHHS was significantly higher postoperatively in patients with complete versus partial tears (95.5 versus 85.7).

CONCLUSION

Endoscopic proximal hamstring repair is an effective approach that provides patients significant improvement in pain and function.

LEVEL OF EVIDENCE

IV, Case Series.

Excellent clinical outcome and low complication rate after proximal hamstring tendon repair at mid-term follow up

PURPOSE

Proximal hamstring tendon avulsions lead to a significant loss of strength and a functional deficit of the respective lower limb and surgery is the recommended treatment. Only little is known about the clinical outcomes and complications when comparing acute and chronic management as well as partial and complete tears. Therefore, the purpose of this study was to investigate the clinical results and the complication rate of patients after surgical treatment of proximal hamstring tendon injuries. It was hypothesized that surgical treatment of an acute proximal hamstring avulsion would lead to a superior clinical outcome with a low complication rate and high return to sports rate compared to chronic cases and partial avulsions.

METHODS

Patients who underwent proximal hamstring tendon repair between 2008 and 2015 were retrospectively evaluated with a minimum follow up of 2 years. Outcome measurements were obtained by means of Lysholm score, Harris Hip Score, Visual Analog Scale, and Tegner Activity Scale. Return to sports (RTS) rate was determined. Postoperative adverse events were recorded and complications reported. Patients' outcomes were compared between acute/chronic repair and partial/complete injury patterns.

RESULTS

Ninety-four of 120 (78.3%) were available for final assessment at a mean follow-up of 56.2 ± 27.2 months. Clinical outcome measures were excellent and did not differ between the treatment groups or between the different injury patterns. RTS was achieved by 86.2% of the patients and was significantly superior after acute treatment (p < 0.05). The overall complication rate was 8.5% and significantly higher in complete tears compared to partial tears and in delay compared to acute surgery (p < 0.05).

CONCLUSION

Surgical treatment of proximal hamstring tendon avulsions results in excellent clinical outcome scores and a high RTS rate. Open surgical treatment has shown to be a safe procedure with a low complication rate. Surgical timing is important, as early surgical intervention provides a higher RTS rate and a lower complication rate than delayed surgery and should therefore be preferred in clinical practice. Repair of partial and complete tears lead to similar clinical outcome, but a higher complication rate in complete avulsions.

LEVEL OF EVIDENCE

Level IV.

Strength assessment after proximal hamstring rupture: A critical review and analysis

BACKGROUND

Muscular strength should be one of the main parameters to assess the interest or not of surgery after proximal hamstring rupture. Yet, this parameter is difficult to compare between the different studies because of the heterogeneous assessment methods.

METHODS

We realized a critical review of strength assessment methods used to evaluate treatments performed after proximal hamstring rupture. The studies were selected from several medical databases with the keywords: "proximal hamstring rupture" OR "proximal hamstring avulsion" AND "strength" OR "isokinetic".

FINDINGS

24 articles evaluated muscular strength after proximal hamstring rupture. 7 have been excluded because the method was not described. 6 types of dynamometric evaluation were used: 2 with an isometric method, 3 with a pneumatic isotonic method and 13 with an isokinetic method. Muscular strengths after non-surgical treatment could not be compared because of the low number of studies and different methods of assessment. After surgery, only isokinetic results measured at the angular speed of 60°/s could have been weighted. A 15% strength deficit was shown at >12 months after surgery.

INTERPRETATION

Muscular strength assessment methods currently used to evaluate the strength after proximal hamstring rupture are too disparate to clearly define the strength deficit after rupture and surgery. Strength evaluation should be more rigorous in order to prove the real interest of the surgical management.

Accelerated rehabilitation results in good outcomes following acute repair of proximal hamstring ruptures

PURPOSE

To assess outcomes of patients who underwent proximal hamstring repair utilizing an accelerated rehabilitation protocol with immediate weight bearing as tolerated and no bracing.

METHODS

Retrospective chart review identified 47 proximal hamstring tendon repairs with suture anchors in 43 patients performed during 2008-2015. Rehabilitation included no immobilization or limited weightbearing. Patients were contacted by phone to assess outcomes utilizing the lower extremity functional score (LEFS), single-assessment numeric evaluation (SANE), and Marx activity scale. Overall patient-reported scores were calculated and results of acute and chronic repairs compared.

RESULTS

Thirty-four patients (38 repairs, 80.8%) were available for follow-up at mean of 4.1 ± 2.0 years following repair. There were two re-tears: one complete rupture 5 weeks postoperative and one partial rupture 10 weeks postoperative in the chronic group. Patients in general reported low pain and good function with a mean LEFS score of 87 ± 21%, a mean SANE score of 88.1 ± 11.6, and a mean numeric pain score of 8.5 ± 15.3 in the last week and 12.2 ± 21.1 with activity. The acute repair group was noted to have a higher mean LEFS score (93.7 versus 79.8%, p = 0.004) and SANE score (91.3 versus 83.8, p = 0.047), and lower pain with activity (21.7 versus 4.8, p < 0.001) as compared to the chronic group.

CONCLUSIONS

Repair of acute proximal hamstring ruptures results in good function and pain relief with the use of a rehabilitation protocol that does not require weight-bearing restrictions or bracing.

LEVEL OF EVIDENCE

III, therapeutic.

Portal Placement and Biomechanical Performance of Endoscopic Proximal Hamstring Repair

BACKGROUND

Proximal hamstring tendon avulsions are debilitating and commonly cause pain, weakness, and functional limitations. Open surgical repair has been the standard, but improved endoscopic techniques have enabled proximal hamstring fixation with decreased risk of infection and numbness, without the morbidity of a large incision.

PURPOSE/HYPOTHESIS

The purpose was to (1) describe pertinent anatomy surrounding the proximal hamstring origin in relation to 4 endoscopic portal sites and (2) test for biomechanical differences between open and endoscopic repair. It was hypothesized that (1) endoscopic proximal hamstring repair is efficacious with respect to commonly used portals and (2) there is no biomechanical difference between open and endoscopic techniques.

STUDY DESIGN

Descriptive and controlled laboratory study.

METHODS

Proximal hamstring ruptures were simulated endoscopically in 10 fresh-frozen human cadaveric pelvis specimens. Endoscopic repair was then completed on 1 limb from each specimen through 4 portals. After repair, each specimen was dissected in layers and measurements from portal tracts to pertinent anatomy were obtained. Open repair was performed on all contralateral limbs, followed by cyclical biomechanical tensile testing to failure of both the open and endoscopically repaired hamstring tendons to assess failure load and local tissue strain.

RESULTS

On average, no portal tract was closer than 2.0 cm to the sciatic nerve or inferior gluteal neurovascular bundle. Anatomic landmarks were identified that could improve the reproducibility and safety of the procedure. Biomechanical testing revealed no differences between the open and endoscopic repair techniques for any measured parameter.

CONCLUSION

This study supports the safety and efficacy of endoscopic proximal hamstring repair through anatomic and biomechanical analyses and helps establish reproducible and recognizable landmarks that define a safe working zone.

CLINICAL RELEVANCE

This study maps the anatomic landscape of the proximal hamstring as encountered endoscopically and demonstrates equivalent biomechanical strength of endoscopic proximal hamstring repair, supporting this technique's safety and efficacy.

The proximal hamstring avulsion clinical trial (PHACT)-a randomised controlled non-inferiority trial of operative versus non-operative treatment of proximal hamstrings avulsions: study protocol

INTRODUCTION

The treatment of proximal hamstring avulsions is controversial. While several trials have investigated the outcome for patients treated surgically, there is today no prospective trial comparing operative treatment with non-operative treatment. This protocol describes the design for the proximal hamstring avulsion clinical trial (PHACT)-the first randomised controlled trial of operative versus non-operative treatment for proximal hamstring avulsions.

METHODS AND ANALYSIS

PHACT is a multicentre randomised controlled trial conducted across Sweden, Norway and Finland. Eligible patients (60 participants/treatment arm) with a proximal hamstring avulsion of at least two of three tendons will be randomised to either operative or non-operative treatment. Participants allocated to surgery will undergo reinsertion of the tendons with suture anchors. The rehabilitation programme will be the same for both treatment groups. When patient or surgeon equipoise for treatment alternatives cannot be reached and randomisation therefore is not possible, patients will be invited to participate in a parallel observational non-randomised cohort. The primary outcome will be the patient-reported outcome measure Perth hamstring assessment tool at 24 months. Secondary outcomes include the Lower Extremity Functional Score, physical performance and muscle strength tests, patient satisfaction and MR imaging. Data analysis will be blinded and intention-to-treat analysis will be preformed.

ETHICS AND DISSEMINATION

Ethical approval has been granted by the Ethical Committee of Uppsala University (DNR: 2017-170) and by the Norwegian ethical board (REC: 2017/1911). The study will be conducted in agreement with the Helsinki declaration. The findings will be disseminated in peer-reviewed publications.

TRIAL REGISTRATION NUMBER

NCT03311997.

Reconstruction of chronic proximal hamstring avulsion injuries using ipsilateral distal hamstring tendons results in good clinical outcomes and patient satisfaction

PURPOSE

To report outcomes following proximal hamstring reconstruction employing an ipsilateral distal hamstring tendon autograft, in patients with chronic proximal ruptures.

METHODS

Six patients presenting with a chronic proximal hamstring avulsion and a medial time from injury of 11.0 months (range 7-18), confirmed via magnetic resonance imaging, underwent proximal hamstring repair using a free graft harvested from the ipsilateral distal hamstrings. Patients were evaluated at 6, 12 and 24 months post-surgery, via the Perth Hamstring Assessment Tool, the Short Form Health Survey, the Lower Extremity Functional Scale, a Patient Satisfaction Questionnaire, the Active Knee Extension and 6 min walk tests, the single and triple hop tests for distance, and isokinetic knee extensor and flexor strength. Knee strength was assessed at 180° and 240°/s (total work, peak and average torque), and both mean absolute scores and limb symmetry indices (LSIs) comparing the operated and non-operated limbs were presented.

RESULTS

Patients demonstrated good clinical improvement throughout the post-operative timeline in all subjective and objective outcomes. Mean knee extensor LSIs had recovered by 12 and 24 months. At 24 months post-surgery, while mean LSIs for knee flexor peak and average torque were at (or above) 90%, a significant difference still existed between the operated and non-operated limbs in knee flexor total work. At 24 months, five patients (83%) were satisfied with the results of the surgery, as well as their ability to return to recreational and sporting activities. There were two adverse events including an early deep vein thrombosis and a secondary surgery to remove a loosened staple.

CONCLUSIONS

While isokinetic hamstring strength had not fully recovered by 24 months, this surgical technique demonstrated a high level of patient satisfaction and return to function, in patients with chronic proximal hamstring ruptures. As the clinical relevance, this surgical technique provides a viable option with good post-operative outcomes for patients with chronic proximal hamstring tears that cannot be approximated back to the ischium.

LEVEL OF EVIDENCE

IV.

Proximal hamstring tendon avulsion treatment choice depends on a combination of clinical and imaging-related factors: a worldwide survey on current clinical practice and decision-making

Objectives

To evaluate current practice in the treatment of proximal hamstring tendon avulsions and identify decision-making preferences.

Methods

An invitation to an anonymous e-survey containing 32 questions was sent to 3475 members of the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) and the European College of Sports and Exercise Physicians (ECOSEP).

Results

We received 403 (12%) unique responses with a completion rate of 79%. Participants were orthopaedic/trauma surgeons (90%), sports medicine physicians (7%) or physical therapists (2%). For 83% of the participants, the preferred treatment (ie, surgical or non-operative) depends on the individual case. Participants base their decision-making process on patient- and injury-related factors (decision modifiers). The five most frequently selected decision modifiers that support the choice for surgical treatment were diminished function (84%), neurological symptoms (74%), involved tendons (82%), tendon retraction on MRI (84%) and patient preference for surgery (78%). The majority prefer early surgical repair (<2 weeks after injury) to achieve highest functional outcome (63%) and ensure a low complication risk (61%). Suture anchors are used by 93% of the participants for tendon reattachment. Estimated recovery duration (ie, time to return to sports) was a median 12 weeks (IQR: 12–20) for non-operative treatment and 17 weeks (IQR: 12–24) for surgical treatment. Estimated reinjury risk was a median 25% (IQR: 10–31.5) and 10% (IQR: 5–20), respectively.

Conclusion

This survey among experienced medical professionals has summarised current practice and identified treatment decision-making preferences. The typical surgical patient has a retracted (>2 cm) two-tendon avulsion (ie, common tendon and semimembranosus tendon), is unable to engage in sports or activities of daily life, reports sciatic symptoms and prefers surgical treatment. Surgery is thought to prolong recovery and decrease reinjury risk compared with non-operative treatment and is preferably performed early.

Level of evidence

Level V.

Return to Sport After Proximal Hamstring Tendon Repair: A Systematic Review

Background:

Previous studies have evaluated functional outcomes and return-to-sport rates after proximal hamstring tendon (HT) repair.

Purpose:

To systematically review the literature in an effort to evaluate return-to-sport rates after proximal HT repair.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A systematic review was performed by searching PubMed, the Cochrane Library, and Embase to identify studies that evaluated postoperative lower extremity function and return-to-sport rates in patients after proximal HT repair. Search terms used were “hamstring,” “repair,” “return to sport,” and “return to play.” Patients were assessed based on return to sport, return to preinjury activity level, type of HT tear (complete or partial), and interval from injury to surgery. Patients were also divided into subgroups depending on timing of the surgical intervention: early, <1 month; delayed, 1 to 6 months; and late, >6 months from the time of injury.

Results:

Sixteen studies (one level 2, five level 3, ten level 4) met the inclusion criteria, including 374 patients with a complete proximal HT tear (CT group) and 93 patients with a partial proximal HT tear (PT group), with a mean follow-up of 2.9 years. Overall, 93.8% of patients (438/467) returned to sport, including 93.0% (348/374) in the CT group and 96.8% (90/93) in the PT group (P = .18). The mean time to return to sport was 5.7 months, and 83.5% of patients (330/395) returned to their preinjury activity level. The early group demonstrated the greatest rate of return to sport at 94.4% (186/197) as well as the quickest time to return at a mean of 4.8 months, although this was not found to be statistically significant.

Conclusion:

Over 90% of patients undergoing repair of a complete or partial proximal HT tear can be expected to return to sport regardless of the tear type. Early surgical interventions of these injuries may be associated with a quicker return to sport, although the rate of return to sport does not differ based on timing of the surgical intervention.

Patient-reported outcomes after surgical and non-surgical treatment of proximal hamstring avulsions in middle-aged patients

Objectives

In the literature on proximal hamstring avulsions, only two studies report the outcomes of non-surgically treated patients. Our objective was to compare subjective recovery after surgical and non-surgical treatment of proximal hamstring avulsions in a middle-aged cohort.

Methods

We included 47 patients (33 surgically and 14 non-surgically treated) with a mean (SD) age of 51 (±9) years in a retrospective cohort study. Follow-up time mean (SD) of 3.9 (±1.4) years. The outcome variables were the Lower Extremity Functional Scale (LEFS) and questions from the Proximal Hamstring Injury Questionnaire. Outcome variables were adjusted in regression models for gender, age, American Society of Anestesiologits (ASA) classification and MRI findings at diagnosis.

Results

The baseline characteristics showed no differences except for the MRI result, in which the surgically treated group had a larger proportion of tendons retracted ≥ 2 cm. The mean LEFS score was 74 (SD±12) in the surgically treated cohort and 72 (SD±16) in the non-surgically treated cohort. This was also true after adjusting for confounders. The only difference in outcome at follow-up was the total hours performing physical activity per week, p=0.02; surgically treated patients reported 2.5 hours or more (5.2 vs 2.7).

Conclusion

This study on middle-aged patients with proximal hamstring avulsions was unable to identify any difference in patient-reported outcome measures between surgically and non-surgically treated patients. The vast majority of patients treated surgically had complete proximal hamstring avulsions with ≥ 2 cm of retraction. We conclude that to obtain an evidence-based treatment algorithm for proximal hamstring avulsions studies of higher scientific level are needed.

Avulsion fracture of the ischial tuberosity treated with the suture bridge technique: a case report

Background

In cases of avulsion fracture of the ischial tuberosity in which the bone fragments are substantially displaced, nonunion may cause pain in the ischial area. Various surgical procedures have been reported, but achieving sufficient fixation strength is difficult.

Case presentation

We treated a 12-year-old male track-and-field athlete with avulsion fracture of the ischial tuberosity by suture anchor fixation using the suture bridge technique. The boy felt pain in the left gluteal area while running. Radiography showed a left avulsion fracture of the ischial tuberosity with approximately 20-mm displacement. Union was not achieved by conservative non-weight-bearing therapy, and muscle weakness persisted; therefore, surgery was performed. A subgluteal approach was taken via a longitudinal incision in the buttocks, and the avulsed fragment was fixed with five biodegradable suture anchors using the suture bridge technique.

Conclusions

Although the majority of avulsion fractures of the ischial tuberosity can be treated conservatively, patients with excessive displacement require surgical treatment. The suture bridge technique provided secure fixation and enabled an early return to sports activities.

Outcomes After Operative and Nonoperative Treatment of Proximal Hamstring Avulsions: A Systematic Review and Meta-analysis

BACKGROUND

No meta-analysis has compared outcomes of operative and nonoperative proximal hamstring avulsion treatment.

PURPOSE

To compare outcomes of operative and nonoperative proximal hamstring avulsion treatment, including acute, chronic, partial, and complete repairs.

STUDY DESIGN

Meta-analysis.

METHODS

PubMed, CINAHL, SPORTdiscus, Cochrane Library, EMBASE, and Web of Science were searched up to July 2016. Three authors screened the studies and performed quality assessment using criteria from the Methodologic Index for Nonrandomized Studies. A best evidence synthesis was subsequently used.

RESULTS

Twenty-four studies (795 proximal hamstring avulsions) were included. Twenty-two studies included proximal hamstring avulsion repairs; 1 study had proximal hamstring avulsion repairs and a control group of nonoperatively treated proximal hamstring avulsions; and 1 study had solely nonoperatively treated proximal hamstring avulsions. The majority of studies were of low methodological quality. Overall, repairs had significantly higher patient satisfaction (90.81% vs 52.94%), hamstring strength (85.01% vs 63.95%), Lower Extremity Functional Scale scores (72.77 vs 69.53), and single-legged hop test results (119.1 vs 56.62 cm) (all P < .001); complications occurred in 23.17% of cases. Compared with chronic repairs, acute avulsion repairs had greater patient satisfaction (95.48% vs 83.79%), less pain (1.07 vs 3.71), and greater strength (85.2% vs 82.8%), as well as better scores for the Lower Extremity Functional Scale (75.64 vs 71.5), UCLA activity scale (University of California, Los Angeles; 8.57 vs 8.10), and Single Assessment Numeric Evaluation (93.36 vs 86.50) (all P < .001). Compared with partial avulsion repairs, complete avulsion repairs had higher patient satisfaction (89.64% vs 81.35%, P < .001), less pain (1.87 vs 4.60, P < .001), and higher return to sport or preinjury activity level, but this was insignificant (81.43% vs 73.83%, P = .082). Partial avulsion repairs had better hamstring strength (86.04% vs 83.71%, P < .001) and endurance (107.13% vs 100.17%, P < .001). Complete repairs had significantly higher complication rates (29.38% vs 11.27%, P = .001).

CONCLUSION

Proximal hamstring avulsion repair resulted in superior outcomes as compared with nonoperative treatment, although the complication rate was 23.17%. The nonoperative group was quite small, making a true comparison difficult. Acute repairs have better outcomes than do chronic repairs. Complete avulsion repairs had higher patient satisfaction, less pain, and a higher complication rate than partial avulsion repairs, although partial avulsion repairs had better hamstring strength and endurance. Studies of high methodological quality are lacking in terms of investigating the outcomes of proximal hamstring avulsion repairs.

Anatomy of the Pudendal Nerve and Other Neural Structures Around the Proximal Hamstring Origin in Males

PURPOSE

To define the anatomy of the pudendal nerve in relationship to the proximal hamstring and other nearby neurological structures during proximal hamstring repair.

METHODS

Six fresh-frozen human cadaveric hemi-pelvises from male patients ages 64.0 ± 4.1 years were dissected in prone position with hips in 10° flexion to identify the relationship of proximal hamstring origin to surrounding neurologic structures including the pudendal nerve, sciatic nerve, and posterior femoral cutaneous nerve. Two independent observers used digital calipers to measure distances.

RESULTS

The pudendal nerve emerged at the inferior border of the piriformis muscle 6.3 ± 1.4 cm from the superior aspect of the proximal hamstring origin. It passed the superior border of the sacrotuberous ligament 3.0 ± 0.6 cm from the superior aspect and 3.9 ± 0.7 cm from the medial aspect of the hamstring origin. It crossed the inferior border of the sacrotuberous ligament 3.0 ± 0.4 cm from the superior aspect and 2.7 ± 0.7 cm from the medial aspect of the proximal hamstring origin. The shortest distance from the hamstring origin to the pudendal nerve was 2.6 ± 0.5 cm from the superior aspect and 2.3 ± 0.8 cm from the medial aspect. The shortest distance from the hamstring origin to the pudendal nerve was located deep to the sacrotuberous ligament in all cadavers. The sciatic nerve was an average of 1.1 ± 0.1 cm lateral to the lateral aspect of the proximal hamstring origin. The posterior femoral cutaneous nerve was located between the hamstring origin and the sciatic nerve, 0.7 ± 0.2 cm lateral to the lateral aspect of the proximal hamstring origin.

CONCLUSIONS

The proximal hamstring origin lies in close proximity to surrounding nerves, including the pudendal, sciatic, and posterior femoral cutaneous nerves.

CLINICAL RELEVANCE

Knowledge that the pudendal nerve lies 2 to 3 cm superior and medial to the proximal hamstring origin may help to prevent iatrogenic damage during surgical dissection and retraction when performing proximal hamstring repair or deep gluteal space endoscopy.

Variability of United States Online Rehabilitation Protocols for Proximal Hamstring Tendon Repair

Background

The optimal postoperative rehabilitation protocol following repair of complete proximal hamstring tendon ruptures is the subject of ongoing investigation, with a need for more standardized regimens and evidence-based modalities.

Purpose

To assess the variability across proximal hamstring tendon repair rehabilitation protocols published online by United States (US) orthopaedic teaching programs.

Study Design

Cross-sectional study.

Methods

Online proximal hamstring physical therapy protocols from US academic orthopaedic programs were reviewed. A web-based search using the search term complete proximal hamstring repair rehabilitation protocol provided an additional 14 protocols. A comprehensive scoring rubric was developed after review of all protocols and was used to assess each protocol for both the presence of various rehabilitation components and the point at which those components were introduced.

Results

Of 50 rehabilitation protocols identified, 35 satisfied inclusion criteria and were analyzed. Twenty-five protocols (71%) recommended immediate postoperative bracing: 12 (34%) prescribed knee bracing, 8 (23%) prescribed hip bracing, and 5 (14%) did not specify the type of brace recommended. Fourteen protocols (40%) advised immediate nonweightbearing with crutches, while 16 protocols (46%) permitted immediate toe-touch weightbearing. Advancement to full weightbearing was allowed at a mean of 7.1 weeks (range, 4-12 weeks). Most protocols (80%) recommended gentle knee and hip passive range of motion and active range of motion, starting at a mean 1.4 weeks (range, 0-3 weeks) and 4.0 weeks (range, 0-6 weeks), respectively. However, only 6 protocols (17%) provided specific time points to initiate full hip and knee range of motion: a mean 8.0 weeks (range, 4-12 weeks) and 7.8 weeks (range, 0-12 weeks), respectively. Considerable variability was noted in the inclusion and timing of strengthening, stretching, proprioception, and cardiovascular exercises. Fifteen protocols (43%) required completion of specific return-to-sport criteria before resuming training.

Conclusion

Marked variability is found in both the composition and timing of rehabilitation components across the various complete proximal hamstring repair rehabilitation protocols published online. This finding mirrors the variability of proposed rehabilitation protocols in the professional literature and represents an opportunity to improve patient care.

A Comparison of Nonoperative and Operative Treatment of Complete Proximal Hamstring Ruptures

Background:

The early repair of acute proximal hamstring ruptures provides better clinical results than delayed repair. However, it is unclear how nonoperative treatment compares with the operative treatment of these injuries.

Purpose:

To compare the clinical results of the nonoperative and operative treatment of acute proximal hamstring ruptures.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

A total of 25 patients with complete, retracted proximal hamstring ruptures presenting to 1 institution were retrospectively reviewed. All patients were given the option of proximal hamstring repair at the time of the initial evaluation. Patients with at least 12 months of follow-up from the time of surgery or injury were included in the evaluation. Both nonoperative and operative treatment groups were evaluated using the same outcome measures. The primary outcome measure was the Lower Extremity Functional Scale (LEFS). Secondary outcome measures included the Short Form–12 (SF-12) physical and mental component summaries, strength testing, a single-leg hop test, the patient’s perception of strength, and the ability to return to activity.

Results:

There were 11 patients treated nonoperatively, with a mean follow-up of 2.48 ± 3.66 years, and 14 patients treated operatively, with a mean follow-up of 3.56 ± 2.11 years. The mean LEFS scores for the nonoperative and operative groups were 68.50 ± 7.92 and 74.71 ± 5.38, respectively (P = .07). No statistical differences were found between the groups regarding SF-12 scores and mean single-leg hop distance compared with the uninjured leg. Isometric testing of the injured hamstring in the nonoperative group demonstrated significant clinical weakness compared with the uninjured side at both 45° and 90° of flexion (57.54% ± 7.8% and 67.73% ± 18.8%, respectively). Isokinetic testing of the injured leg in the operative group demonstrated 90.87% ± 16.3% strength of the uninjured leg. All patients in the operative group were able to return to preinjury activities, whereas 3 patients in the nonoperative group were unable to return (chi-square = 4.33, P = .07).

Conclusion:

Patients with acute proximal hamstring ruptures treated surgically regained approximately 90% strength of the uninjured extremity and tended to have a greater likelihood of returning to preinjury activities than patients treated nonoperatively.

Proximal hamstring tendon avulsion surgery: evaluation of the Perth Hamstring Assessment Tool

PURPOSE

The purpose of the present study was to validate a new scoring system for proximal hamstring injury-the Perth Hamstring Assessment Tool (PHAT).

METHODS

This is a prospective series of 74 consecutive proximal hamstring surgical repairs in 72 patients, with a median age of 50.5 years (range 16-74). Patients completed the PHAT, SF12 Health Survey and Lower Extremity Functional Scale (LEFS). The scoring system was validated by calculating its internal consistency, reproducibility, reliability and sensitivity to change. Construct validity was evaluated using Pearson's correlation analysis to examine the strength of association between the PHAT, LEFS and SF-12 scores.

RESULTS

The PHAT showed high completion rate (100 %), high internal consistency (Cronbach's alpha 0.80), high reproducibility (ICC 0.84) and high sensitivity to change. There was moderate correlation with the LEFS and low correlation with the Physical Component Score of the SF-12.

CONCLUSION

This study has validated the PHAT as an assessment tool for proximal hamstring tendon injuries. The new questionnaire provides a measure of outcome that is reliable and sensitive to clinically important change. This simple questionnaire provides the clinician with a quick and practical tool for assessing patients with proximal hamstring injuries: to assess pre-operative disability and monitor recovery post-operatively.

LEVEL OF EVIDENCE

II.

Outcome After Surgical Repair of Proximal Hamstring Avulsions: A Systematic Review

BACKGROUND

At the present time, no systematic review, including a quality assessment, has been published about the outcome after proximal hamstring avulsion repair.

PURPOSE

To determine the outcome after surgical repair of proximal hamstring avulsions, to compare the outcome after acute (≤4 weeks) and delayed repairs (>4 weeks), and to compare the outcome after different surgical techniques.

STUDY DESIGN

Systematic review and best-evidence synthesis.

METHODS

PubMed, CINAHL, SPORTdiscus, Cochrane library, EMBASE, and Web of Science were searched (up to December 2013) for eligible studies. Two authors screened the search results separately, while quality assessment was performed by 2 authors independently using the Physiotherapy Evidence Database (PEDro) scale. A best-evidence synthesis was subsequently used.

RESULTS

Thirteen studies (387 participants) were included in this review. There were no studies with control groups of nonoperatively treated proximal hamstring avulsions. All studies had a low methodological quality. After surgical repair of proximal hamstring avulsion, 76% to 100% returned to sports, 55% to 100% returned to preinjury activity level, and 88% to 100% were satisfied with surgery. Mean hamstring strength varied between reporting studies (78%-101%), and hamstring endurance and flexibility were fully restored compared with the unaffected side. Symptoms of residual pain were reported by 8% to 61%, and reported risk of major complications was low (3% rerupture rate). No to minimal difference in outcome was found between acute and delayed repair in terms of return to sports, patient satisfaction, hamstring strength, and pain. Achilles allograft reconstruction and primary repair with suture anchors led to comparable results.

CONCLUSION

The quality of studies included is low. Surgical repair of proximal hamstring avulsions appears to result in a subjective highly satisfying outcome. However, decreased strength, residual pain, and decreased activity level were reported by a relevant number of patients. Minimal to no differences in outcome of acute and delayed repairs were found. Limited evidence suggests that an Achilles allograft reconstruction yields results comparable with primary repair in delayed cases where primary repair is not possible. High-level studies are required to confirm these findings.

Gross anatomical and dimensional characteristics of the proximal hamstring origin

PURPOSE

The current study was undertaken to better define the gross anatomical and dimensional characteristics of the proximal hamstring origin.

METHODS

Twelve paired whole-lower extremities from six embalmed cadavers were dissected. The gross anatomy of the proximal hamstrings was studied. With the tendons attached to the ischial tuberosity, the width and thickness of each tendon was measured 1 cm distally to their origin, and the distance from the most proximal border of the common origin of the semitendinosus (ST) and long head of the biceps (LB) to their distal junction was assessed. After removal of the hamstring group, the shape, orientation, and dimension of the tendon footprints were determined.

RESULTS

One cadaver demonstrated unique anatomy, which was considered as an anatomic variant and was therefore excluded from the study group. The ST and LB had a common origin on the posterolateral aspect of the ischial tuberosity (ST/LB), whereas the semimembranosus (SM) had a separated origin at the anterolateral aspect. The mean distance from the most proximal border of the ST/LB origin to the distal junction was 10.0 ± 1.3 cm. The shape of both footprints was longitudinal-oval, with the longitudinal axes of the SM and ST/LB footprints parallel aligned. Mean tendon width was 3.4 ± 0.5 cm for the common ST/LB complex and 4.2 ± 0.9 cm for the SM (p = 0.009). The corresponding values for tendon thickness were 1.0 ± 0.3 cm (ST/LB) and 0.8 ± 0.2 cm (SM), respectively (n.s.). Mean footprint length was 3.9 ± 0.4 cm for ST/LB and 4.5 ± 0.5 cm for SM (p = 0.002). The corresponding values for footprint height were 1.4 ± 0.5 cm (ST/LB) and 1.2 ± 0.3 cm (SM), respectively (n.s.).

CONCLUSION

The ST and LB had a common origin, whereas the SM originated separately. The site of origin of both tendons was the lateral aspect of the ischial tuberosity, with the SM footprint lying directly anterior to the footprint of the ST/LB complex. The footprint of the SM was significantly wider than the footprint of the ST/LB. The reported gross anatomic findings and dimensions may aid surgeons in anchor placement at the anatomical attachment site, thereby facilitating anatomic hamstring repair. In addition, the provided data may improve diagnosis and conservative treatment of proximal hamstring tendinopathy, since detailed knowledge about the normal anatomy is crucial for recognizing tendon abnormalities and for several conservative treatment modalities such as shockwave application or ultrasound-guided injections.

Proximal Hamstring Repair Strength: A Biomechanical Analysis at 3 Hip Flexion Angles

Background:

Proximal hamstring repair for complete ruptures has become a common treatment. There is no consensus in the literature about postoperative rehabilitation protocols following proximal hamstring repair. Some protocols describe bracing to prevent hip flexion or knee extension while others describe no immobilization. There are currently no biomechanical studies evaluating proximal hamstring repairs; nor are there any studies evaluating the effect of different hip flexion angles on these repairs.

Hypothesis:

As hip flexion increases from 0° to 90°, there will be a greater gap with cyclical loading.

Study Design:

Controlled laboratory study.

Methods:

Proximal hamstring insertions were detached from the ischial tuberosity in 24 cadavers and were repaired with 3 single-loaded suture anchors in the hamstring footprint with a Krakow suture technique. Cyclic loading from 10 to 125 N at 1 Hz was then performed for 0°, 45°, and 90° of hip flexion for 1500 cycles. Gap formation, stiffness, yield load, ultimate load, and energy to ultimate load were compared between groups using paired t tests.

Results:

Cyclic loading demonstrated the least amount of gap formation (P < .05) at 0° of hip flexion (2.39 mm) and most at 90° of hip flexion (4.19 mm). There was no significant difference in ultimate load between hip flexion angles (326, 309, and 338 N at 0°, 45°, and 90°, respectively). The most common mode of failure occurred with knot/suture failure (n = 17).

Conclusion:

Increasing hip flexion from 0° to 90° increases the displacement across proximal hamstring repairs. Postoperative bracing that limits hip flexion should be considered.

Clinical Relevance:

Repetitive motion involving hip flexion after a proximal hamstring repair may cause compromise of the repair.

Structural properties of the intact proximal hamstring origin and evaluation of varying avulsion repair techniques: an in vitro biomechanical analysis

BACKGROUND

Although surgical repair has been reported to provide improved outcomes compared with nonoperative treatment in the management of complete proximal hamstring origin avulsions, no intact or avulsion repair biomechanical data exist to support various repair strategies or guide postoperative rehabilitation.

PURPOSE

To compare failure load among 4 proximal hamstring tendon conditions: (1) intact, (2) repair with 2 small anchors (2S), (3) repair with 2 large anchors (2L), and (4) repair with 5 small anchors (5S).

STUDY DESIGN

Controlled laboratory study.

METHODS

Twenty-four human cadaveric hemipelvises were randomly allocated to 1 of the 4 testing groups. Intact and repaired specimens were subjected to cyclic loading at 1 Hz between 25 N and a progressively increasing maximum load that was incremented by 200 N every 50 cycles, beginning at 200 N and increasing to 1600 N. Displacement, maximum load, stiffness, number of cycles to failure, and mode of failure during cyclic loading were recorded and analyzed.

RESULTS

The intact proximal hamstring tendons failed at the highest cyclic force of all tested groups, yet no significant differences existed between the intact (1405 ± 157 N) and 5S repair (1164 ± 294 N) conditions. Both the 2S and the 2L repair groups failed at a level significantly lower than the intact hamstring (474 ± 145 N [P < .001] and 543 ± 245 N [P < .001], respectively). The maximum load attained by the 5S repairs was significantly greater than the loads attained by the 2S (P = .005) and 2L (P = .013) repairs.

CONCLUSION

Repairs using 5 small anchors were similar to the intact tendon and were significantly stronger than repairs using only 2 large or 2 small anchors in the repair of complete avulsions of the proximal hamstring tendons. Additionally, no significant differences in strength were observed when only anchor size differed.

CLINICAL RELEVANCE

This finding supports the clinical investigation of postoperative range of motion rehabilitation protocols that permit full flexion and extension of the hip and knee when a 5-anchor repair construct is used.