A qualitative and quantitative analysis of the attachment sites of the proximal hamstrings

Evaluation of 3D Footprint Morphology of Knee-Related Muscle Attachments Based on CT Data Reconstruction: A Feasibility Study

A three-dimensional (3D) understanding of muscle attachment footprints became increasingly relevant for musculoskeletal modeling. The established method to project attachments as points ignores patient-specific individuality. Research focuses on investigating certain muscle groups rather than comprehensively studying all muscles spanning a joint. Therefore, we present a reliable method to study several muscle attachments in order to reconstruct the attachment sites in 3D based on CT imaging for future applications in musculoskeletal modeling. For the present feasibility study, 23 knee-related muscle attachments were CT-scanned postmortem from four nonadipose male specimens. For this, the specific muscle attachments were dissected and marked with a barium sulfate containing paint (60 g BaSO4 in 30 mL water and 10 mL acrylic paint). Subsequently, bone geometries and muscle attachments were reconstructed and evaluated from CT datasets. Bone morphology and footprint variations were studied. Exemplarily, variations were high for pes anserinus insertions (mean 56%) and the origins of M. biceps femoris (mean 54%). In contrast, the origins of the vastus muscles as well as the insertion of the Achilles tendon showed low variation (mean 9% and 13%, respectively). Most attachment sites showed variation exceeding the individuality of bone morphology. In summary, the present data were consistent with the few published studies of specific muscle footprints. Our data shed light on the high variability of muscle attachments, which need to be addressed when studying muscle forces and movements through musculoskeletal modeling. This is the first step to achieving a more profound understanding of muscle morphology to be utilized in numerical simulations.

The direct muscular origin of the semitendinosus: a pitfall in categorization of proximal hamstring tendon tears

The ischial origin of the hamstring musculature is complex. While the conjoint tendon and semimembranosus are commonly discussed and understood by radiologists, there is a lesser-known origin of the semitendinosus along the inferior and medial surface of the ischium in the form of a broad direct muscular connection. This secondary origin is infrequently described in the radiology literature and is a potential pitfall during grading of semitendinosus injuries if the interpreting physician is unaware of its presence. In a proximal hamstring tendon tear, the direct muscular origin of the semitendinosus can be spared, torn along with the conjoint tendon, or remain intact and contribute to a vertical shearing injury of the semitendinosus myotendinous junction. Detailed knowledge of this anatomy and its imaging appearance in the setting of injury enables the reader to correctly diagnose these unique hamstring injuries.

Pathogenesis and Diagnosis of Proximal Hamstring Tendinopathies

The proximal hamstring complex is a highly vulnerable area that is especially prone to injury. Proximal hamstring tendinopathies (PHTs) remain challenging in diagnosis, treatment, rehabilitation, and prevention due to a large variety of different injuries, slow healing response, persistent symptoms, and functional impairments. PHTs are often misdiagnosed or underdiagnosed, leading to delayed treatment and therapy failure. In addition, many athletes are at a high risk of PHT recurrence, a leading cause of prolonged rehabilitation and impaired individual performance. Until now, there have been no clear criteria for the diagnosis and classification of PHT. Tendinopathies can be graded based on their symptoms and onset. Additionally, radiological characteristics exist that describe the severity of tendinopathies. The diagnosis usually includes a battery of pain provocation tests, functional tests, and imaging to ensure a proper classification. Understanding the specific tasks in the pathogenesis and diagnostic process of PHT requires knowledge of functional anatomy, injury pattern and pathophysiological mechanisms as well as examination and imaging techniques. This work provides a structured overview of the pathogenesis and diagnostic work-up of PHT, emphasizing structured examination and imaging to enable a reliable diagnosis and rapid treatment decisions.

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.

US and MRI of Pelvic Tendon Anatomy and Pathologic Conditions

The bony pelvis serves as the attachment site for a large number of powerful muscles and tendons that drive lower extremity movement. Organizing the pelvic tendons into groups that share a common function and anatomic location helps the radiologist systematically evaluate these structures for injury, which can be caused by repetitive stress, acute trauma, or failure of degenerated tissues. Tears of the anteromedial adductors around the pubic symphysis and anterior flexors traversing anterior to the hip principally affect younger male athletes. Tears of the lateral abductors and posterior extensors are more common in older individuals with senescent tendinosis. The deep external rotators are protected and rarely injured, although they can be impinged. Imaging of the pelvic tendons relies primarily on US and MRI; both provide high spatial and contrast resolution for soft tissues. US offers affordable point-of-care service and dynamic assessment, while MRI allows simultaneous osseous and articular evaluation and is less operator dependent. While the imaging findings of pelvic tendon injury mirror those at appendicular body sites, radiologists may be less familiar with tendon anatomy and pathologic conditions at the pelvis. The authors review pertinent anatomy and imaging considerations and illustrate common injuries affecting the pelvic tendons. Online supplemental material is available for this article. ^©RSNA, 2022.

Physical therapeutic options for residual sacrotuberous ligament pain after treatment of sacroiliac joint dysfunction

[Purpose] To evaluate the incidence of pain originating from the sacrotuberous ligament after sacroiliac joint treatment, and to determine effective physical therapeutic options for sacrotuberous ligament pain. [Participants and Methods] Among 303 patients with sacroiliac joint dysfunction, 57 patients (20 males, 37 females) with persistent lower-buttock pain after sacroiliac joint injections were included in the study. The incidence of sacrotuberous ligament pain and the physical findings from the first evaluation were investigated by physical therapists. [Results] Diagnostic sacrotuberous ligament injections identified lower-buttock pain originating from the sacrotuberous ligament in 57.9% of the patients (33 out of 57 patients) after treatment of sacroiliac joint dysfunction. Of these, 11 patients experienced relief after sacrotuberous ligament injection alone; the others required physical therapy. Sacrotuberous ligament relaxation alone was effective in eight patients; biceps femoris relaxation was required in eight patients; and gluteus maximus contraction exercise was required in six patients. [Conclusion] After sacroiliac joint treatment, the incidence of residual sacrotuberous ligament pain in the persisting lower-buttock pain was 57.9%. In addition to sacrotuberous ligament relaxation, biceps femoris relaxation was effective in patients who showed both higher differences in the straight leg raising test and biceps femoris tenderness, while gluteus maximus contraction exercises were effective in patients with gluteus maximus weakness.

Morphological study on the origin of the semitendinosus muscle in the long head of biceps femoris

Hamstring muscle injuries are the most prevalent among athletes who engage in sprinting activities. Their most frequent location is where the long head of the biceps femoris joins with the semitendinosus muscle to form the conjoint hamstring tendon. Just distal to this area, an additional group of fibers of the semitendinosus originate from medial aspect of biceps femoris. The objective of this study was to analyze the morphological characteristics of this union and to discuss its potential role in hamstring tears. Anatomical dissection was performed on 35 thighs. Samples obtained from this region were sectioned and stained with Masson's trichrome for further histological evaluation. A group of fibers from the semitendinosus muscle originating from the long head of the biceps femoris were observed in all 35 specimens. This origin was located 67 ± 12 mm from the ischial tuberosity and was 32 ± 14 mm in length. This group of muscle fibers had a width of 10.9 ± 5.3 mm and a thickness in the anteroposterior axis of 3.2 ± 1.4 mm. Its pennation angle was 9.2 ± 1.5 degrees. Microscopic examination showed muscle cells from both muscles contacting interposed tendinous tissue. In conclusion, fibers of the semitendinosus muscle consistently arise from the proximal aspect of the long head of biceps femoris. The morphological characteristics of this junction have functional implications. The horizontal component of the semitendinosus vector could pull the long head of the biceps femoris medially during its shortening-lengthening cycle, rendering it an intrinsic risk factor for hamstring injuries.

Prognosis of Incomplete Avulsion of the Proximal Hamstring Tendon Is Determined by the Avulsion Location of the Proximal Hamstring Tendon Footprint

OBJECTIVE

To test the hypothesis that prognosis of incomplete avulsion of the proximal hamstring tendon would be worse whether avulsion location reached the proximal part of the conjoined tendon (CJ) footprint or not.

DESIGN

Retrospective chart review.

SETTING

Outpatient specialty clinic.

PATIENTS

We reviewed 345 consecutive athletes with hamstring injury.

INTERVENTIONS

Based on magnetic resonance imaging, incomplete avulsion of the proximal hamstring tendon was divided into 2 cases according to avulsion location without (cases A) or with (cases B) avulsion of the proximal part of the CJ footprint.

OUTCOME MEASURES

We compared the time until return to play, subjective outcomes, and success rate of avoiding surgery between cases.

RESULTS

Incomplete avulsion of the proximal hamstring tendon was detected in 47 athletes (13.6%). Thirty-four athletes were classified as cases A, and 13 as cases B. Forty-two athletes (89.4%) were followed up until return to play. The median time from pain onset to return to play was significantly longer in cases B than in cases A (B, 39.3 weeks; A, 8.0 weeks; P = 0.00015). Subjective outcomes at return to play were significantly poorer in cases B than in cases A (P = 0.00054). Success rate of avoiding surgery were significantly poorer in cases B (55%) than in cases A (100%) (P = 0.00062).

CONCLUSIONS

Incomplete avulsion of the proximal hamstring tendon was observed in 13.6% of hamstring injuries. Return to play, subjective outcomes, and success rate of avoiding surgery were significantly poorer with avulsion of the proximal part of the CJ footprint.

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.

Editorial Commentary: Proximal Hamstring Injuries-Is the Hip to Blame?

There is a growing understanding of the relation between femoroacetabular impingement (FAI) and injury to adjacent structures. Patients with proximal hamstring pathology appear to have a high prevalence of underlying FAI. The kinetic chain phenomenon is a potential explanation of the high correlation between proximal hamstring injury and underlying FAI of the hip.

Anatomy of proximal attachment, course, and innervation of hamstring muscles: a pictorial essay

Hamstring injuries are very common in sports medicine. Knowing their anatomy, morphology, innervation, and function is important to provide a proper diagnosis, treatment as well as appropriate prevention strategies. In this pictorial essay, based on anatomical dissection, the detailed anatomy of muscle-tendon complex is reviewed, including their proximal attachment, muscle course, and innervation. To illustrate hamstrings' role in the rotational control of the tibia, the essay also includes the analysis of their biomechanical function.Level of evidence V (expert opinion based on laboratory study).

Proximal Hamstring Injuries: Management of Tendinopathy and Avulsion Injuries

PURPOSE OF REVIEW

To outline the typical presentation, physical examination, diagnostic imaging, and therapeutic treatment options for proximal hamstring injuries to improve awareness, expedient diagnosis, and definitive management.

RECENT FINDINGS

Proximal hamstring tendinopathy and partial-thickness tears can often successfully be managed with a combination of non-operative modalities, including physiotherapy focused on eccentric strengthening, extracorporeal shock wave therapy, or peri-tendinous injections. Surgery is reserved for refractory cases, but can yield good outcomes. Contrastingly, non-operative treatment often leads to unsatisfactory outcomes in complete ruptures, with residual weakness and reduced function with poor return-to-sport rates. Instead, surgical repair can provide satisfactory outcomes, with good-to-excellent functional outcomes and strength, with acute treatment preferred over delayed, chronic repair. Hamstring tendinopathy and partial-thickness tears can be successfully treated non-operatively with good functional outcomes, with surgical repair reserved for refractory cases. Complete tears are best managed with surgical repair, allowing improved strength and functional outcomes.

Predictors of Clinical Outcomes After Proximal Hamstring Repair

Background

Proximal hamstring avulsions cause considerable morbidity. Operative repair results in improved pain, function, and patient satisfaction; however, outcomes remain variable.

Purpose

To evaluate the predictors of clinical outcomes after proximal hamstring repair.

Study Design

Case series; Level of evidence, 4.

Methods

We retrospectively reviewed proximal hamstring avulsions repaired between January 2014 and June 2017 with at least 1-year follow-up. Independent variables included patient demographics, medical comorbidities, tear characteristics, and repair technique. Primary outcome measures were the Single Assessment Numerical Evaluation (SANE), International Hip Outcome Tool-12 (iHOT-12), and Kerlan-Jobe Orthopaedic Clinic (KJOC) Athletic Hip score. Secondary outcome measures included satisfaction, visual analog scale for pain, Tegner score, and timing of return to sports.

Results

Of 102 proximal hamstring repairs, 86 were eligible, 58 were enrolled and analyzed (67%), and patient-reported outcomes were available for 45 (52%), with a mean 29-month follow-up. The mean patient age was 51 years, and 57% were female. Acute tears accounted for 66%; 78% were complete avulsions. Open repair was performed on 90%. Overall satisfaction was 94%, although runners were less satisfied compared with other athletes (P = .029). A majority of patients (88%) returned to sports by 7.6 months, on average, with 72% returning at the same level. Runners returned at 6.3 months, on average, but to the same level 50% of the time and at a decreased number of miles per week compared to nonrunners (15.7 vs 7.8, respectively; P < .001). Postoperatively, 78% had good/excellent SANE Activity scores, but the mean Tegner score decreased (from 5.5 to 5.1). Acute tears had higher SANE Activity scores. The mean iHOT-12 and KJOC scores were 99 and 77, respectively. Endoscopic repairs had equivalent outcome scores to open repairs, although conclusions were limited given the small number of patients in the endoscopic group. Greater satisfaction was noted in patients older than 50 years (P = .024), although they were less likely to return to running (P = .010).

Conclusion

Overall, patient satisfaction and functionality were high. With the numbers available, we were unable to detect any significant differences in functional outcome scores based on patient age, sex, body mass index, smoking status, medical comorbidities, tear grade, activity level, or open versus endoscopic technique. Acute tears had better SANE Activity scores. Runners should be cautioned that they may be unable to return to the same preinjury activity level after proximal hamstring repair.

Clinical Relevance

When counseling patients with proximal hamstring tears, runners and those with chronic tears should set appropriate expectations.

A systematic review of the morphology and function of the sacrotuberous ligament

The sacrotuberous ligament (STL) has been linked to conditions such as pelvic girdle pain and pudendal nerve entrapment, yet its contribution to pelvic stability is debated. The purpose of this review was to explore the current understanding of the STL and highlight any gaps in knowledge regarding its anatomy and function. A systematic search of the literature was conducted, focussing on the morphology and attachments of the STL, the relationship of the STL with surrounding structures, and its neurovascular supply and function. A total of 67 papers and four textbooks were obtained. The attachment sites of the STL are largely consistent; however, the extent of its connections with the long head of biceps femoris, gluteus maximus, piriformis, the posterior layer of the thoracolumbar fascia, and sacrospinous ligament are unclear. Morphometric parameters, such as mean STL length (6.4-9.4 cm), depth (0.3-0.4 cm), and width (1.8-3.5 cm, at its mid-point) are variable within and between studies, and little is known about potential side-, age-, or sex-related differences. The STL is pierced in several sites by the inferior and superior gluteal arteries, but information on its innervation pattern is sparse. Functionally, the STL may limit sacral nutation but it appears to have a limited contribution to pelvic stability. Some morphological aspects of the STL warrant further investigation, particularly its connections with surrounding structures, innervation pattern and function. Knowledge of the detailed anatomy and function of this ligament is important to better understanding its role in clinical conditions. Clin. Anat. 32:396-407, 2019. © 2018 Wiley Periodicals, Inc.

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.

Editorial Commentary: Should Proximal Hamstring Surgery Make You Nervous?

In recent times, there has been an increased awareness of high-grade proximal hamstring injuries, many of which are now being managed surgically. Yet, surgical treatment of these injuries is challenging and carries potential risks of serious neurologic complications. Indeed, it is likely that postoperative neurologic complications are under-recognized. As such, knowledge of the intimate anatomic relation of the pudendal nerve and other neural structures around the proximal hamstring is essential and should provide a road map for safer and more successful surgery.

Comparison of hip extensor muscle activity including the adductor magnus during three prone hip extension exercises

OBJECTIVES

This study compared the role of the adductor magnus muscle (Amag) as a hip extensor while performing active prone hip extension (PHE), PHE with hip adduction (PHE-ADD), and PHE with hip abduction (PHE-ABD) with the gluteus maximus (Gmax) and hamstrings.

METHODS

The study recruited 22 healthy participants. Electromyography data were recorded from the Amag, Gmax, and medial and lateral hamstrings during PHE, PHE-ADD, and PHE-ABD. Normalized electromyographic data were examined using one-way, repeated-measures analyses of variance.

RESULTS

The magnitude of the Amag, Gmax, and hamstring activations did not differ significantly while performing PHE (p = 0.41). Furthermore, the Amag and hamstring activations were significantly greater than the Gmax activation when performing PHE-ADD (p < 0.05). The Gmax showed significantly greater activation during PHE-ABD than the Amag and medial and lateral hamstrings (p < 0.05).

CONCLUSIONS

Based on these results, we advocate including the Amag as a hip extensor during the PHE test or exercise. Our preliminary results have the potential to be applied directly to the PHE test, for investigating the muscle-activation pattern of the Amag with the Gmax and hamstrings in patients with hip or lower back pain.

A New Technique for Surgical Treatment of Proximal Hamstring Tendinopathy in a Triathlon Athlete

Introduction:

Proximal hamstring tendinopathy (PHT) is the result of chronic overload caused by repetitive eccentric contraction. Surgical treatment becomes an option for patients with chronic symptoms that do not respond to conservative treatment.

Case Report:

This report describes a case of a 48-year-old man, an amateur triathlete, with deep gluteal pain in the left hip for 12 months, leading to a decline in sports performance. Magnetic resonance imaging revealed abnormalities that suggested a PHT. Surgery was indicated following the failure of conservative treatments. Debridement of the conjoint tendon and its reinsertion associated with semimembranosus tenotomy showed good results and is thus an option for the treatment of this pathology after 12 months of follow-up.

Conclusion:

This article provides surgeons with a new surgical option for this debilitating condition with clinical and functional improvement after 12 months of follow-up.

Repair of Proximal Hamstring Tears: A Surgical Technique

Proximal hamstring tears are among the most common sports-related injuries. These injuries often occur as strains or partial tears at the proximal muscle belly or the musculotendinous junction, with avulsion injuries of the proximal attachment occurring less frequently. Regardless of the mechanism, they produce functional impairment and negatively affect an athlete's performance. Various classifications for these injuries are reported in the literature. Early surgical treatment is recommended for patients with either a 2-tendon tear/avulsion with more than 2 cm retraction or those with complete 3-tendon tears. Surgery can be performed in the chronic phase but it is technically demanding because of scar formation and tendon retraction. This Technical Note describes a biomechanically validated surgical technique for repair of the proximal hamstring tears.

The prevalence of proximal hamstring pathology on MRI in the asymptomatic population

PURPOSE

Injury to the proximal hamstring complex (PHC) is becoming more frequently diagnosed. Patients attending our tertiary referral centre demonstrated 'pathological changes' in the unaffected normal contralateral PHC on MRI. The prevalence of PHC pathology, however, has not been previously documented in the literature in asymptomatic subjects. It is the hypothesis of this study that the natural history of asymptomatic pathological change on MRI in the PHC is not clear. The aim is to quantify the natural history of PHC degeneration.

METHOD

Two hundred and fifty-three consecutive patients with an asymptomatic PHC were reviewed retrospectively between 2009 and 2010. The PHC was assessed in multiple MRI planes by a specialist musculoskeletal consultant radiologist.

RESULTS

Five hundred and six proximal hamstrings complexes were reviewed. Eighty-nine patients (35 %) were radiological normal both sides, median age 51 years (range 13-88). Thirty-four patients (13 %) had unilateral pathology, median age 55 years (range 25-89). Of these, 3 patients (1 %) had presence of a complete tear, median age 81 years (range 72-87). Sixteen patients (7 %) had tendinosis, median age 60 years (range 37-78). Fifteen patients (6 %) had a unilateral partial tear, median age 57 years (range 35-78). One hundred and thirty patients (52 %) had bilateral pathology, median age 65 years (range 25-89). Fifty-three patients (21 %) had the presence of bilateral tendinopathy alone, median age 56 years (range 25-89). Twenty-seven patients (11 %) had a partial tear on one side and tendinosis on the other, median age 68 years (range 38-89). Thirty-nine patients (15 %) had evidence of bilateral partial tears, median age 63 years (range 36-89), with 52 % demonstrating a torn conjoined and semi-membranosus tendon. The remaining 48 % had either an isolated tear of the conjoined or the semi-membranosus (the more commonly injured tendon 74 % of the time). Four patients (2 %) had bilateral complete ruptures with a median age of 68 years (range 59-78). Six patients (2 %) had a complete tear on one side and a partial tear on the other, median age 68 years (range 34-83). One patient had a complete tear on one side and tendinosis on the other, age 81 years.

CONCLUSION

There is a higher prevalence of pathology in the asymptomatic population, 15 % have bilateral partial tears, and 2 % have bilateral complete tears. The semi-membranosus being the most affected, this may help clinically stratify the need for surgical intervention.

LEVEL OF EVIDENCE

I.

Proximal Hamstring Tendinopathy: Clinical Aspects of Assessment and Management

Synopsis Proximal hamstring tendinopathy (PHT) typically manifests as deep buttock pain at the hamstring common origin. Both athletic and nonathletic populations are affected by PHT. Pain and dysfunction are often long-standing and limit sporting and daily functions. There is limited evidence regarding diagnosis, assessment, and management; for example, there are no randomized controlled trials investigating rehabilitation of PHT. Some of the principles of management established in, for example, Achilles and patellar tendinopathy would appear to apply to PHT but are not as well documented. This narrative review and commentary will highlight clinical aspects of assessment and management of PHT, drawing on the available evidence and current principles of managing painful tendinopathy. The management outline presented aims to guide clinicians as well as future research. J Orthop Sports Phys Ther 2016;46(6):483-493. Epub 15 Apr 2016. doi:10.2519/jospt.2016.5986.

The adductor magnus "mini-hamstring": MRI appearance and potential pitfalls

OBJECTIVE

To examine the anatomic MRI characteristics of the adductor magnus mini hamstring (AMMH) and explore its involvement in cases of hamstring avulsion.

MATERIALS AND METHODS

An IRB-approved retrospective review of patients undergoing "hamstring protocol" MRI between March 2009 and June 2014 was performed. Two musculoskeletal radiologists recorded multiple AMMH anatomic characteristics and involvement in cases of hamstring avulsion.

RESULTS

Seventy-six AMMHs were analyzed in 66 patients [35 females and 31 males, mean age 49.3 ± 15.2 years (range 17-81)]. Eleven percent of AMMHs were poorly visualized, 51 % visualized, and 37 % well visualized. Seven percent demonstrated round, 73 % ovoid, and 21 % flat/lenticular tendon morphologies. Most (88 %) demonstrated typical origins. Average cross-sectional area (CSA) was 22.4 ± 10.6 mm² (range 6-56), diameter was 7.2 ± 2.5 mm (range 2.9-15), medial distance from the semimembranosus tendon was 7.5 ± 2.5 mm (range 3-14), and tendon length was 6.8 ± 3.3 cm (range 1.2-14.1). There was no gender difference in AMMH anatomic measurements or correlation between age and CSA or diameter. Of 17 complete hamstring avulsion cases, the AMMH was intact in 13, partially torn in 3, and completely torn in 1.

CONCLUSION

The AMMH is a constant finding with variable anatomic characteristics. It is visualized or well visualized by MRI in 88 % of cases and is a sizable tendon located in close proximity to the semimembranosus tendon. Because it is uncommonly completely torn (6 %) in cases of complete hamstring avulsion, radiologists should be aware of its presence and appearance to avoid diagnostic confusion.

Radiographic Identification of Arthroscopically Relevant Proximal Femoral Structures

BACKGROUND

Anatomic landmarks located on the proximal femur have only recently been defined, and there is a lack of radiographic guidelines for their locations presented in the literature. With the confident identification of these landmarks, radiographs could provide more assistance in preoperative evaluations, intraoperative guidance, and postoperative assessments.

PURPOSE

To quantify the radiographic locations of endoscopic landmarks of the proximal femur.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Ten cadaveric specimens were dissected, and radio-opaque hardware was placed for each landmark of interest. Radiographs were obtained and measurements recorded in anteroposterior (AP) and Dunn 45° views.

RESULTS

In the AP view, the gluteus medius insertion was located a mean 12.9 ± 2.4 mm and 34.7 ± 5.1 mm from the piriformis fossa and vastus tubercle, respectively. The piriformis fossa was a mean 14.8 ± 5.9 mm and 4.9 ± 1.9 mm from the anterior and posterior tips of the greater trochanter, respectively. The anterior and posterior tips of the greater trochanter were a mean 14.8 ± 5.1 mm from each other. In the Dunn 45° view, the piriformis fossa was a mean 13.3 ± 2.0 mm, and the vastus tubercle was a mean 21.5 ± 6.0 mm, from the gluteus medius insertion. Moreover, the vastus tubercle was a mean 33.5 ± 6.4 mm from the anterior tip of the greater trochanter and 31.6 ± 8.5 mm from the posterior tip of the greater trochanter.

CONCLUSION

In spite of the variation in cadaveric sizes, quantitative descriptions of endoscopic landmarks were reproducible in clinical views.

CLINICAL RELEVANCE

A detailed understanding of how the described landmarks present radiographically is relevant to preoperative planning, intraoperative evaluations, and postoperative assessments.

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.