Background

According to recent research, tendon injuries have been estimated to be as high as 30% to 50% of all sports injuries and 50% of injuries to elite endurance runners. About 6% of sedentary people will experience a tendon injury, and proximal hamstring tendinopathy (PHT) is common in long-distance runners.^1,2 Current research demonstrates evidence that overuse, poor lumbopelvic stability, and relatively weak hamstring musculature contribute to PHT development.³ Commonly noted symptoms include pain with prolonged sitting on hard surfaces, pain with forward trunk flexion, and pain with running, often noted during the swing phase.⁴

Ultrasound-guided needle tenotomy (NT) has been recently used as a successful treatment intervention for patients with tendinopathy.⁵ Ultrasound-guided NT works by repeatedly inserting a needle into the damage tissue with the goal of transforming tissue that is in the chronic disease state, to an acute inflammatory process in order to bring blood flow to the area and promote healing of the previously damaged tissue.⁵ Current literature points to safe, successful treatment in patients suffering with gluteal tendinopathy, achilles tendinopathy, and lateral tendinopathy in reducing pain and improving function with ultrasound-guided NT.^6–9

To date, there is no research describing the effect of ultrasound-guided NT in patients with PHT. Therefore, the purpose of this case study was to describe the effects of ultrasound-guided NT in conjunction with PRP injection and eccentric training for the treatment and management of PHT on pain, sitting tolerance, lower extremity function, and running. This case report was prepared following CARE guidelines.

Case Presentation

Subjective

The patient was a 58-year-old female who presents with bilateral buttock pain (R>L) attributable to PHT. The patient had been accustomed to regular exercise daily, including strength training, cycling, yoga, golfing, and running. The patient first noted pain in the right lower extremity running on a treadmill in April 2013, which was thought to be secondary residual effects of a lipomatous tumor removal in “fall of 2012”. The patient reported noticing pain in the right buttock region following surgery years prior. The patient reported pain 10/10 on the Numeric Pain Rating Scale (NPRS), where zero indicated no pain and 10 is the worst with pain ranging from 7/10 at best to 10/10 during specific tasks. Her pain was exacerbated by sitting particularly on hard surfaces longer than 15 minutes, any attempted walking at an incline, and especially with running with inability to run during initial visit due to 10/10 pain when attempted. The patient underwent PRP injections in November of 2013 by an orthopedic surgeon with minimal improvement, in addition to failing conservative physical therapy consisting of gluteal strengthening, gait training, and manual therapy to reduce pain. The patient reported that she was exercising normally, with increased pain during running and assuming certain yoga positions. Over four years, the patient had a gradual decline in her ability to run secondary to the new onset of bilateral buttock pain, with her right buttock pain worse than her left. Her ability to run was dramatically reduced and eventually stopped and was replaced with walking as a substitute. The results of recent diagnostic ultrasound were also as follows: there was a significant cortical irregularity of the surface of the right ischial tuberosity. There was increased hyperemia under color-flow Doppler, suggesting some degree of ongoing tendinosis, with the right proximal hamstring origin more pronounced than the left. At least moderate tendinosis of the right proximal hamstring was made evident by a thickened and hypoechoic appearance. Additionally, there was calcification within the proximal tendon with two well-defined calcific deposits. There was no significant hyperemia on color flow Doppler to suggest active inflammation. Due to the progression of symptoms, the patient received another PRP injection in April of 2017.

Objective

During the physical exam, the physical therapist examined the patient’s lumbar spine, SIJ, and bilateral hips, with spine and SIJ being cleared due to having normal range of motion and joint mobility without exacerbation of symptoms during testing. Palpation presented tenderness over the inferior aspect of the ischial tuberosity at the insertion of the proximal hamstring bilaterally, with the right ischial tuberosity being more tender than the left ischial tuberosity. The patient also performed isokinetic testing to determine hamstring strength and quadriceps to hamstring ratio. The results from the initial isokinetic testing (Table 1.) and initial MMT results (Table 4.) can be seen below. Additionally, results from patient specific functional scale (PSFS) (Table 6.) and lower extremity functional scale (LEFS) (Table. 7) are found below.

Neurological sensation to light touch was altered in the right lower extremity in the femoral nerve distribution due to previous surgical history.

Differential Diagnosis

At the conclusion of the initial evaluation, a differential diagnosis list was attained. Due to the patients mechanism of injury, the following diagnoses were included in her differential diagnosis list: (1) femoroactebular impingement, (2) deep gluteal pain syndrome, (3) dural tension disorder of the lumbar spine, (4) greater trochanteric bursitis, and (5) proximal hamstring tendinopathy. Ultrasound images confirmed proximal hamstring tendinopathy and this diagnosis led to more appropriate physical therapy interventions and ultrasound guided needle tenotomy.

Treatment

The patient had undergone an ultrasound-guided NT plus PRP injection of the bilateral proximal hamstrings in April 2017 by a local orthopedic surgeon, due to the patient plateauing in physical therapy with specific exercise only. Due to the predominance of tendinopathy on the right side, primarily needle tenotomy was performed at the origin of the right hamstring. The patient was advised not to perform any stretching, yoga, or heavy resistance strength training for the next four weeks. She was suggested to continue light walking for one month and following the patient’s return visit to the physician in May of 2017, she began a 4-stage therapeutic exercise program, which continued for six months. The therapeutic exercise program was aimed to increase lower extremity strength through eccentric strengthening and core stabilization, after the ultrasound-guided NT was performed. Exercises in stages 1-2 were performed 5x/week with stage 3 exercises performed 3x/week. The physical therapy plan of care was set for 3x/week and a detailed home exercise program was discussed. Specific exercises performed can be found in Table 2 below.

Outcome/ Follow-Up

After one month following the ultrasound guided needle NT and PRP injection, the patient noted mild improvement. The following are the 4-month and 8-month follow-up of physical performance and patient reporting outcomes. The patient was discharged from formal PT with continued use of HEP at 8-month follow-up.

Initially, the patient could only tolerate 15 minutes of sitting on a hard surface chair with an 8 out of 10 pain rating. At an eight-month follow-up, her ability to sit improved, and she could now tolerate longer distances driving 2-1/2 hours with a rating of 5/10. Initially, the patient was unable to perform jogging, and after eight months, the patient was able to perform a walk-jog interval program for 1 mile in 13-15 minutes at a speed of 4.0-5.3 mph with a rating of 6 out of 10. The patient’s ability to walk up inclines was first rated at a 7 out of 10, and at the end of an 8-month follow-up, she reported her ability to walk up inclines was 3 out of 10 with complaints of heaviness and weakness mostly subsiding.

Discussion

Although significant research in understanding the effectiveness of ultrasound-guided NT and PRP in treating varied sizes of tears is lacking for any musculoskeletal condition, partial tears of 1 cm or less are more likely to respond to NT and PRP compared to tears of larger sizes.¹⁰ However, larger tears do not preclude the possibility of PRP, particularly when no better option exists (i.e. patient has already exhausted conservative therapies, surgery is felt to be either too aggressive of a treatment or with guarded prognosis).¹⁰ The patient had initially undergone PRP injection to her right proximal hamstring tendon years prior (in approximately 2011 per patient report) for a similar issue. She had noted minimal relief from the first injection and did not follow through with further injections or treatment, and unfortunately, symptoms persisted, which then became bilateral. We intended to investigate the possibility of evaluating ultrasound-guided NT and PRP injections in conjunction with the use of eccentric loading in treating proximal hamstring tendinopathy.

The management and treatment of proximal hamstring tendinopathy can be a challenging condition to treat in physical therapy.¹¹ There is some difficulty in applying various treatments to symptomatic tendons, mainly because the pathology of symptomatic tendons has not been elucidated, complicating matters further is the mismatch between reported pain (and disability) and imaging (and pathology) as well as evidence of widespread sensory nervous system sensitization and some tendinopathies.^12,13 There is also evidence to suggest that PHT is a more difficulty tendinopathy to treat than other tendinopathies, including lateral elbow and shoulder due to repetitive overuse of the lower extremities and weight bearing through the lower extremities.⁴

Although isolated eccentric loading regimes for tendinopathy have been widely accepted as the treatment of choice, the potential mechanisms behind this intervention remain unclear.¹ Muscles can produce greater maximal force eccentrically than concentrically and would suggest a potential for greater mechanical stimulation.¹⁴ A study by Couppe et al. would suggest that eccentric exercise is superior to the treatment of PHT than concentric exericse.¹ It has also been reported that the evidence of nervous system sensitization in persistent painful tendinopathy may exist but requires more comprehensive sensory testing. Moreover, diagnosis and treatment should go beyond focusing on tendons locally to consider possible central nervous system mechanisms.^15,16

Although the patient’s ability to tolerate sitting had improved, the incorporation of using a cushion was greatly helpful in improving sitting tolerance. There appeared to be no remarkable improvement when being subjected to sitting on harder surfaces. The patient had progressed her ability to achieve running, in which she performed running 1 mile with a pain rating of 6 out of 10. Her difficulty in carrying out this task was also obscured by past surgery, which involved removing an atypical lipoma of the right inguinal area, which caused peripheral numbness and a sense of instability during this activity. Upon reexamination using diagnostic ultrasound, there appeared to be no significant changes in tissue structure, but this comes with some degree of uncertainty based on the location of the tendon structures in finding changes.

One of the basic principles of diagnostic ultrasound is that the frequency of the transducer used in the evaluation decides both the image’s depth and clarity. Higher frequency transducers (typically 12–15 MHZ in musculoskeletal ultrasound) can see superficial structures in detail but lack the capabilities to see deeper structures.^17,18 Lower frequency transducers (typically 5MHZ transducers) can see much deeper but with much less detail. Therefore, there are limitations in visualizing deeper musculoskeletal structures, including the tendon surrounding the hip, on musculoskeletal ultrasound. While viewing outcome measures and isokinetic testing, it showed physical changes of improvement in both function and strength, so can we assume there is some benefit in incorporating an exercise program in treating conditions of this nature in conjunction with ultrasound-guided NT and PRP injections.

Furthermore, the persistence of symptoms without complete resolution may be that this patient’s condition is in the degenerative tendinopathy stage in which there is little capacity for reversibility of pathological change. Several limitations need to be considered when interpreting the results of this case report. First, the diagnosis of this patient initially was proximal hamstring tendinopathy, which is difficult to treat due to its chronic nature.^3–5 Second, the type of transducer used was of a higher frequency, which can detect superficial structures in detail but lacks the capabilities to see deeper structures. This may be why it was difficult to notice any pathological change in tissue initially. Finally, there may have been limited monitoring of pain levels in patients performing regular activities of daily living and performing higher-level recreational activities, which may inhibit proper healing.

Learning Points

• This case report demonstrates the effectiveness of ultrasound-guided needle tetonomy, PRP injections, and eccentric exercise in treating PHT to reduce pain and improve functional independence.

• Future research will need to focus on larger sample sizes and superior methodological design to increase external validity and promote the use of ultrasound-guided needle tenotomy in treating PHT for physical therapists.

Appendix

*Right proximal hamstring partial tear

*Needle Tenotomy (NT) inserted proximally near the ischial tuberosity

*Right proximal hamstring partial tear, short axis