Editor’s Note: This is article #2 of a six-part series. Part 1 appeared in the August issue.
Subacute Injuries: Repair in Motion
In the subacute phase (days to several weeks post-injury), the body ramps up fibroblast activity, collagen synthesis and angiogenesis.1 Clinically, this is when pain, swelling and functional decline emerge - but the potential for healing is still high.
However, these injuries are often mismanaged. Training through pain, delayed care, and incomplete rehab shift the healing trajectory toward degeneration.
Chronic Injuries: Inflammation Gone Rogue
Chronic soft-tissue injuries emerge when repair fails to complete. Rather than returning to healthy architecture, tissues become fibrotic, vascularized and disorganized.2 Classic examples include:
- Tendinopathies
- Bursitis
- Chronic ligamentous injuries
Disrupted collagen, inflammatory infiltration, and neovascularization are hallmarks of this phase.3
Rotator-Cuff Case Study: Microtrauma to Degeneration
Overhead athletes suffer cumulative damage to the supraspinatus, often resulting in partial-thickness tears and tendinosis. Histology shows increased type III collagen, neovascularization, and fiber disorganization.4
The glenoid labrum is also vulnerable. Repeated high-velocity motion produces SLAP lesions, detaching the biceps anchor and compromising stability.5
The Elbow Under Siege – UCL Breakdown: In throwers, the ulnar collateral ligament (UCL) is frequently overloaded. Chronic valgus stress leads to microtears and fibrocartilaginous metaplasia.6 Ligament attenuation is visible on imaging, and clinically presents as medial pain and reduced throwing power.
Nonsurgical Victory: A 25-year-old pitcher presents with supraspinatus tearing and subacromial bursitis. Nonsurgical intervention with dextrose prolotherapy, high-intensity laser therapy, and neuromuscular rehab restores pitching mechanics and performance – without surgery.
From the Micro to the Macro: CNS Response
Injury alters motor control. The CNS adjusts by inhibiting injured tissues and recruiting compensators. Studies show increased upper trapezius activation in place of inhibited serratus anterior in rotator-cuff pathology.7
Inflammation: A Double-Edged Sword
Subacute injuries benefit from the immune cascade (IL-1ß, TNF-ɑ). Chronic injuries, however, trap tissues in cycles of inflammation, fibrosis and disorganization.8
Clinical Takeaway
Left unchecked, subacute injuries evolve into chronic dysfunction. The longer the delay in proper care, the more extensive the rehab required.
Next in the Series…
In Part 3, The Hidden Architecture of Dysfunction, we’ll explore how compensation patterns form, persist, and reshape neuromuscular function.
References
- Hauser RA, Hauser MA, Baird NM. Evidence-based use of dextrose prolotherapy for musculoskeletal pain: a scientific literature review. J Prolother, 2011;3(4):765-789.
- Alfredson H, et al. Heavy-load eccentric calf muscle training for the treatment of chronic Achilles tendinosis. Am J Sports Med, 1998;26(3):360-366.
- Rompe, J. D., et al. (2009). Eccentric loading versus eccentric loading plus shock-wave treatment for midportion achilles tendinopathy: a randomized controlled trial. Am J Sports Med, 2009;37(3):504-510.
- Riley GP, et al. Tendon degeneration and chronic shoulder pain: changes in the collagen composition of the human rotator cuff tendons in rotator cuff tendinitis. Ann Rheum Dis, 1994;43(6):359-66.
- Calcei JG, et al. Diagnosis and treatment of injuries to the biceps and superior labral complex in overhead athletes. Curr Rev Musculoskel Med, 2018;11(1):63-71.
- Fleisig GS, et al. Kinetics of baseball pitching with implications about injury mechanisms. Am J Sports Med, 1995;23(2):233-239.
- Thigpen CA, et al. Head and shoulder posture affect scapular mechanics and muscle activity in overhead tasks. J Electromyogr Kinesiol, 2010;20(4):701-709.
- Bjordal JM, et al. Low-level laser therapy in acute pain: a systematic review of possible mechanisms of action and clinical effects in randomized placebo-controlled trials. Photomed Laser Surg, 2006;24(2), 158-168.
