Educational webinar recap (December 2025) featuring Mark Gruner, DO, MBA, RMSK
In an educational session hosted by APEX Biologix, Mayo Clinic–trained interventional sports physiatrist Mark Gruner, DO, MBA, RMSK shared an evidence-based, clinic-ready framework for integrating orthobiologics into PM&R and sports medicine workflows. The discussion focused on how Dr. Gruner approaches patient selection, ultrasound-guided technique, adjunct biologic options (including Protein Concentrate/A2M), and structured rehab with the goal of increasing responder rates and improving consistency across common musculoskeletal presentations.
In Dr. Gruner's session, he emphasized a simple, repeatable explanation: PRP is created by drawing autologous blood, centrifuging it, and concentrating platelets - delivering growth factors that influence the local healing environment. In his practice, this sets the stage for informed consent while keeping expectations grounded.
For joint disease, he underscored that PRP is best positioned as a tool to:
support pain reduction and improved function
help down-regulate inflammatory signaling
potentially offer cartilage-protective effects (without claiming cartilage “regeneration”)
He noted that while tendon biology differs from joint pathology, aligning the biologic choice with the tissue problem - and the structural stability of that tissue - is a recurring theme throughout his algorithms.
A core theme in the session was that outcomes improve when practices standardize indications and exclusions. He shared that by developing internal referral criteria and tracking outcomes through a registry approach, his team increased responder rates over time - moving from roughly “good” results to more consistently high response across selected indications.
Dr. Gruner outlined clinical scenarios where PRP tends to perform well, particularly when imaging and mechanics align with the pain generator:
Upper extremity
low-grade/interstitial rotator cuff tears
mild–moderate shoulder arthritis in appropriate morphologic patterns
lateral epicondylopathy (tennis elbow) and medial epicondylopathy (golfer’s elbow)
mild–moderate thumb CMC arthritis
Lower extremity
hip OA (generally Tönnis ≤2) and carefully selected labral pathology
gluteus med/min tendinopathy and partial tearing
hamstring tendinopathy (distinguishing tendon vs muscle targets)
mild–moderate knee OA (especially KL1–2; selective KL3 criteria)
patellar/quad tendinopathy
focal mid-portion Achilles tendinopathy and selected plantar fasciosis cases
For cuff pathology, Dr. Gruner emphasized that “partial tear” is not one diagnosis. He described three practical decision points:
Tear grade and geometry
Low-grade partial tears (<50%) may be reasonable PRP candidates when stability is preserved.
As tears become high-grade or demonstrate instability patterns, outcomes become less predictable.
Where the tear sits matters
He highlighted that tears drifting toward the rotator interval and stabilizing ligaments may behave more “unstable,” particularly when biceps mechanics are affected—changing the risk profile and expectations.
When to add “scaffold” support
In cases where the tissue problem is more than inflammatory tendinopathy, i.e., true partial tearing, he described using PRP combined with a more viscous biologic substrate (such as Protein Concentrate/A2M) in select patients, based on the clinical picture and imaging.
Dr. Gruner also reviewed that some studies and meta-analyses suggest PRP augmentation in the early post-op window may help reduce re-tear rates and improve short-term outcomes while emphasizing technique precision to avoid disrupting repairs.
A clinician-ready point: Dr. Gruner advised classifying shoulder arthritis more precisely (rather than only “severity”) to predict whether orthobiologics are likely to help.
He discussed how glenoid morphology and humeral head centering influence outcomes - suggesting that once structural imbalance or posterior wear patterns become pronounced, biologic injections may not overcome mechanics.
Practical technique note: he frequently aspirates effusion before injection to reduce inflammatory load and improve the environment for the biologic.
Dr. Gruner reinforced that tendinopathy care improves when clinicians treat the problem as 3D pathology rather than a single painful point. His process includes:
measuring tear length and width
using fluid distension to reveal occult tearing
using power Doppler to identify neovascularity and inflammatory patterns
treating both the tear and the “biology” around it, rather than only the insertion footprint
He also reviewed where percutaneous tenotomy (e.g., Tenex) can be appropriate—particularly in tendinopathy without major tearing, and in calcific cases where debridement is part of the solution set.
For hip injections, Dr. Gruner stressed that Tönnis grading alone isn’t enough. His screening includes:
Tönnis grade (often focusing on ≤2)
presence of large cam/pincer deformities, dysplasia angles, and displaced labral tears
differentiating “arthritic pain” from “structural impingement pain”, where PRP may be limited
He described modifying targets (joint vs labrum) depending on age, imaging, and exam patterns.
Dr. Gruner noted that knee OA is the most studied PRP indication, and he pointed to several evidence reviews and professional guidance documents supporting PRP in mild–moderate OA, especially when dose is adequate.
Key clinical pearls he emphasized:
aspirate effusion whenever present before injecting
consider BMI, malalignment, and subchondral edema as outcome modifiers
patellofemoral OA behaves more like a compression-driven pain problem and can be less responsive depending on anatomy (e.g., alta/baja)
In the specific subgroup of recurrent effusion/swelling without another structural driver, Dr. Gruner described using PRP + A2M Protein Concentrate (A2M) (sometimes paired with HA) and noted clinically meaningful improvement in swelling and symptoms in select cases - presented as a practice-based observation aligned with the proposed anti-protease mechanism (MMP modulation).
One of the most transferable clinician takeaways: Dr. Gruner repeatedly emphasized that outcomes depend on pairing injections with structured loading and staged rehab.
He reviewed the concept of tendon healing phases:
early inflammatory window (often a few days of expected symptom flare)
proliferative phase (weeks)
remodeling phase (weeks to months)
He noted that patient education, especially around realistic timelines, reduces “false failures” and improves adherence.
Dr. Gruner’s throughline was consistent: match the biologic to tissue type, stage, and mechanical reality.
PRP: strong fit for many mild–moderate OA and tendinopathies, especially with ultrasound-defined targets
PRP + Protein Concentrate (A2M): considered where inflammatory milieu or recurrent swelling may warrant additional strategy
Microfragmented adipose / other higher-structure options: considered when scaffold/structural support is a priority or when disease is more advanced
Percutaneous tenotomy / tendon scraping: considered for tendinopathy phenotypes where debridement of degenerative tissue and neovascular drivers are central
Want the complete clinical walkthrough - including Dr. Gruner’s ultrasound technique examples, selection nuances (e.g., shoulder morphology, occult tearing), and rehab progression logic? Access the full webinar replay in the APEX Resource Library
References
Disclaimer
This blog post is a summary of an educational session and is provided for informational purposes for healthcare professionals. The perspectives shared reflect the clinical experience and opinions of the speaker(s) and do not necessarily represent the views of APEX Biologix. This content is not medical advice and is not intended to establish a standard of care, diagnose, or recommend treatment for any individual patient. Clinicians should evaluate all therapies using their independent clinical judgment, applicable regulations, and the most current evidence.