Virginia Research Day 2021

Platelet Rich Plasma Therapy for a Latissimus Dorsi Tear in a Baseball Player Caroline Pupke, OMS-IV 1 , Olabode Agaja, D.O. 2 , Brad McCrady, D.O., FAOASM 2

1 Edward Via College of Osteopathic Medicine – Auburn Campus Auburn, AL 2 Edward Via College of Osteopathic Medicine – Virginia Campus Blacksburg, VA

Conclusions

Introduction

Report

Latissimus dorsi tears are uncommon injuries and mainly occur in high-level athletes. These injuries are seen in a variety of sports, including baseball, rock climbing, and water-skiing, with the highest number seen in the throwing shoulder of baseball pitchers 1 . Diagnosis can be challenging as there are no pathognomonic signs or physical exam findings associated with latissimus dorsi tears. Therefore, the clinician must have a high suspicion for this injury. Research has shown that baseball pitchers typically present with acute pain in the upper arm and posterior axilla following a latissimus dorsi tear, with symptoms most severe during ball release and follow-through 2 . Most commonly, there are no pre-existing symptoms related to the latissimus dorsi, but cases of vague posterior tightness and fatigue have been reported leading up to the point of incapacitating injury 2 . Imaging of the shoulder is essential for diagnosis and as it relates to a latissimus dorsi injury should include a shoulder X-ray series, as well as an MRI of the shoulder. MRI is the imaging of choice to diagnose a latissimus dorsi tear as it provides superior detail of the muscle tissue and will demonstrate fluid surrounding the muscle after an acute injury has occurred 3 . Latissimus dorsi tears are classified into 4 grades on MRI, which is seen in figure 1. Latissimus dorsi tears can also be visualized on ultrasound, which is useful when using ultrasound-guided treatment techniques. Once the diagnosis of a latissimus dorsi tear is established, the treatment options can be divided into two categories: operative and non-operative treatment. Patients with full-thickness tears of the latissimus dorsi, or those who fail conservative management are indicated for surgical repair. Non-operative treatment options for latissimus dorsi tears include rest, anti-inflammatory medications, cryotherapy, laser therapy, and rehabilitation with or without an injection 3 . One potential non-operative treatment option is a platelet-rich plasma (PRP) injection.

References Although uncommon, tears of the latissimus dorsi can cause significant dysfunction that can result in reduced throwing velocity, as well as pain during the deceleration phase of throwing. These injuries present a unique challenge for clinicians, as they are often difficult to diagnose and must be considered when baseball pitchers present with shoulder/arm pain. Therefore, clinicians should consider this diagnosis based on the clinical presentation. The MRI of the shoulder can be used to classify the severity of the latissimus dorsi tear as determined by the degree of muscle retraction. Once identified, latissimus dorsi tears can be treated either operatively or non-operatively. Non-operative management is considered the mainstay of treatment when MRI reveals there is a signal along the latissimus dorsi muscle, or the muscle tear is incomplete. Based on this patient’s presentation, non-operative management was successfully pursued and was demonstrated in the literature in the form of an ultrasound-guided PRP injection into the right latissimus dorsi muscle followed by a physical therapy directed throwing progression. In our patient, two months after the injection he continued to progress well through physical therapy with minimal limitations and eventually completed a throwing program. This case demonstrates PRP in conjunction with physical therapy directed at return to throw is a successful treatment option for latissimus dorsi tears. 1.Donohue, B.F., Lubitz, M.G., Kremchek. Sports injuries to the latissimus dorsi and teres major. American Journal of Sports Medicine 2017 (45): 2428-2435. 2.Schickendantz, M.S., Kaar, S.G., Meister, K., et. al. Latissimus dorsi and teres major tears in professional baseball pitchers: a case series. The American Journal of Sports Medicine 2009 (37): 2016-2020. 3.Erickson, B.J., Petronico, N., Romeo, A.A. Approach to latissimus dorsi and teres minor injuries in the baseball pitcher. Current Reviews in Musculoskeletal Medicine 2019 (12): 24-29. 4.Anderson SE, Hertel R, Johnston JO, etc. Latissimus dorsi tendinosis and tear: imaging features of a pseudotumor of the upper limb in five patients. American Journal of Radiology 2005 (185): 1145-1151.

Figure 2 Ultrasound image of the needle tip being inserted during the injection of PRP into the right latissimus dorsi muscle A previously healthy 17-year-old male baseball player presents to the office with right shoulder pain that has been present intermittently for 16 months. He cannot recall an exact inciting event aside from feeling a pull in the shoulder while pitching. The pain is located in the right posterolateral shoulder without radiation. The pain is aggravated during the deceleration phase of throwing, but relieved with stretching. The patient has tried PT in the past but did not have significant improvement in his pain. Physical exam revealed tenderness to palpation in the right posterior axilla without defects. Range of motion testing showed limited active abduction of the right shoulder to 160 degrees without a painful arc. All other range of motion testing of the bilateral shoulders was within normal limits. Prior to the visit to our office, the patient underwent an MRI of his right shoulder, which demonstrated a grade 4 full-thickness tear of the latissimus dorsi at the myotendinous junction with 3-4 cm retraction at the insertion on the humerus. After review of the MRI and exam findings with the patient and his father, various treatment options for the latissimus dorsi tear were discussed. These options included surgical repair, prolotherapy, or a PRP injection. The patient decided to pursue non-surgical treatment and agreed to undergo an ultrasound-guided PRP injection into the right latissimus dorsi tendon. PRP injection was then performed under direct ultrasound visualization directed at the hyperechoic tendinous structure in which 6cc of PRP. Figure 2 shows the insertion of the PRP injection. One month after the injection, the patient had no pain with activities of daily living, and he started physical therapy for upper limb working on strength and range of motion. He continued this for the next 4 weeks. Two months after the PRP injection, the patient was seen for a second follow-up in which he continued to progress well doing a home exercise program for physical therapy and still abstained from throwing. Following this visit the patient progressed to throwing at physical therapy. However, due to pain with activation, it was recommended that the patient hold off on batting and basketball. He later followed up after going through PT directed throwing progression and based on his progress was released to resume throwing as tolerated.

Classification of latissimus dorsi tear on MRI

Figure 1 Classification of latissimus dorsi tear on MRI Full thickness tear with >2 cm tendon retraction Fluid along the latissimus dorsi, teres major muscles Partial thickness tear of the latissimus dorsi muscle Full thickness tear with <2 cm tendon retraction

Grade 1

Grade 2

Special thank you to Dr. Brad McCrady for generously contributing his time and assistance. Acknowledgements

Grade 3

Grade 4

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