Louis Rizio, MD
Share
Team Physician NJIT NCAA Division 1 Athletics
Team Physician Kean University Dr. Rizio is a fellowship trained sports medicine orthopaedic surgeon that treats athletes of all ages and levels. Dr Rizio specializes in Knee and Shoulder Surgery, Cartilage Repair/Regeneration, Arthroscopic Surgery and Sports Related Injuries.
03/31/2026
Check out my new SubStack post on throwing injuries in youth sports. Causes, prevention and patterns discussed. Go to the link to subscribe. https://open.substack.com/pub/sportsmeddoc/p/play-ball?r=82hcv8&utm_medium=ios.
03/04/2026
Great job from all the folks that got this to presentation today! AAOS 2026
Platelet-rich plasma (PRP) promotes tendon healing and repair through several key mechanisms:
- Delivers concentrated growth factors (e.g., PDGF, TGF-β, VEGF) that stimulate tenocyte proliferation, migration, and extracellular matrix synthesis, especially collagen I, which is critical for tendon strength and structure
- Enhances differentiation of tendon stem/progenitor cells into active tenocytes, increasing collagen production and accelerating tissue regeneration.
- Modulates inflammation by reducing pro-inflammatory cytokines and favoring M2 macrophage polarization, creating a regenerative microenvironment.
- Promotes angiogenesis, supporting vascular remodeling and improved nutrient delivery to the healing tendon.
- Increases antioxidant defenses in tenocytes via activation of the Nrf2 pathway, protecting cells from oxidative stress and supporting homeostasis.
- Improves tendon tissue organization, cellularity, and glycosaminoglycan content, leading to more mature and structurally sound tendon repair.
- Recruits stem cells to the wound area through chemoattractant proteins such as HMGB1, further enhancing tissue regeneration.
These combined actions establish a microenvironment that supports both structural and functional tendon recovery, though clinical efficacy may vary depending on PRP preparation and application protocols. 🏋️♀️
10/15/2025
⚾🏐 Shoulder Rotation Deficits & Injury Risk in Overhead Athletes
Dr. Louis Rizio MD | Sports Surgery Specialist
⸻
What Is GIRD?
• Glenohumeral Internal Rotation Deficit (GIRD) = loss of internal rotation in the dominant shoulder.
• Common in overhead athletes: baseball, tennis, volleyball, cricket.
⸻
Why It Matters
• A >15–20° deficit in internal rotation increases risk of shoulder & elbow injuries.
• Reduced total rotational motion (TROM) = higher stress on the joint.
• Alters throwing mechanics → increased torque and impingement risk.
⸻
Key Stats
• ⚠️ ≥25° loss of IR = up to 4× greater injury risk in high school baseball players.
• 🏐 Volleyball players with ≥17° GIRD & ≥5° TROM asymmetry → more shoulder pain.
• GIRD worsens over years of overhead play & is influenced by prior injuries.
⸻
Common Injuries Linked to GIRD
• Rotator cuff tendinopathy or partial tears
• SLAP/labral injuries
• Posterior shoulder tightness & impingement
• UCL strain at the elbow
⸻
Prevention & Management
• 🧘♂️ Sleeper & cross-body stretches
• 💪 Posterior cuff mobility + scapular control work
• 🩺 Regular screening of shoulder rotation during season
• ⚖️ Maintain total shoulder motion within 5° of non-throwing side
⸻
Pro Insight:
Not all GIRD is “bad.” Some loss of IR is a normal throwing adaptation — the key is balance and monitoring total motion, not just one direction.
⸻
Take-Home Message
➡️ GIRD matters — small rotation losses can lead to big injury risks.
➡️ Early detection, consistent mobility work, and season-long monitoring protect performance and longevity.
Click here to claim your Sponsored Listing.
Category
Contact the practice
Website
Address
200 South Orange Avenue, Suite 230
Livingston, NJ
07039
Opening Hours
| Monday | 9am - 5pm |
| Tuesday | 9am - 5pm |
| Wednesday | 9am - 5pm |
| Thursday | 9am - 5pm |
| Friday | 9am - 5pm |
