Fibrous Adhesion: The Most Common Musculoskeletal Pathology? | Novo Soft Tissue

Here's a thought worth sitting with: fibrous adhesion — disorganized scar-like tissue that forms after injury, surgery, or repetitive strain and restricts normal movement between tissue layers — may be the single most common underlying pathology in the entire musculoskeletal system. It just doesn't get counted that way, because it hides under dozens of different diagnostic names depending on which specialist is looking at it and which joint or tissue it shows up in. The genuinely encouraging part of that idea is the second half: of all the ways fibrosis affects the human body, musculoskeletal adhesion may be one of the most directly fixable, for reasons the tissue itself makes possible.

The same process, a dozen different diagnoses

Fibrosis — the excess, disorganized buildup of collagen and scar-like tissue — is a major focus of modern medical research, but almost entirely in the context of organs: pulmonary fibrosis, liver fibrosis in metabolic disease, kidney fibrosis, scleroderma. A 2025 cross-organ review in Nature Reviews Drug Discovery laid out the shared biology across these conditions in detail. It's a genuinely striking omission that the review's list of major fibrotic disease categories doesn't include musculoskeletal tissue at all, even though the same cellular actors — activated fibroblasts turning into myofibroblasts, excess collagen deposition, transforming growth factor-beta (TGF-β) driving the whole process — are just as active in a stiff shoulder capsule or a scarred-down tendon as they are in a scarred liver.

The likely reason musculoskeletal fibrosis doesn't get its own chapter is that it's never been filed under one name. It shows up instead as adhesive capsulitis (frozen shoulder), as arthrofibrosis after a joint injury or surgery, as the disorganized collagen structure found in chronic tendinopathy, as thickened, less mobile thoracolumbar fascia in chronic low back pain, and as the taut, restricted bands felt in myofascial trigger points. Different specialists, different diagnostic codes, different corners of medicine — but a growing body of research suggests the same underlying tissue process connects all of them.

Why it may be the most common pathology of all

The cells responsible for this fork in the road have a name: fibro-adipogenic progenitors, or FAPs. They're resident support cells in muscle and connective tissue that respond to injury by either supporting clean, organized regeneration, or — when inflammation doesn't resolve properly, when tissue isn't remodeled through normal movement, or when the injury repeats before it's fully healed — defaulting toward laying down disorganized fibrotic matrix instead. A 2025 review in The Journal of Physiology frames this explicitly as a "fork in the road": the exact same cell population can go either way, and which path it takes depends heavily on the mechanical and inflammatory environment during healing, not on some conditions being inherently more "scar-prone" than others.

Given how often that fork gets triggered, the scale starts to make sense. Global Burden of Disease data tracked roughly 494 million people living with other musculoskeletal disorders in 2020 — more than double the 221 million recorded in 1990 — with projections putting that figure past a billion by 2050. Every one of those cases involved tissue that was injured, inflamed, or immobilized at some point, which means every one of them ran through that same fibrotic fork in the road at least once. And that's before counting the sheer number of surgeries that create the same risk directly: research on arthrofibrosis after knee surgery alone puts the rate of clinically significant adhesion formation anywhere from 2% to 35% after ACL reconstruction and up to 15% after total knee replacement, depending on how strictly it's defined. Multiply that kind of risk across every joint surgery, every muscle strain, every bout of tendinopathy, and every stretch of forced immobility, and it becomes hard to name a more common musculoskeletal event than "tissue that healed back down with some degree of adhesion."

The genuinely good news: this may be uniquely fixable

Here's where the comparison to organ fibrosis actually works in our favor. That same 2025 cross-organ review was candid about the state of treatment for fibrotic lung, liver, and kidney disease: turning the mechanistic understanding of fibrosis into actual working drugs "continues to be limited and challenging," with only a handful of approved antifibrotic medications, and those limited to pulmonary fibrosis specifically. Fibrotic tissue buried inside a lung or a kidney is extraordinarily hard to reach and influence directly.

Musculoskeletal adhesion has no such problem. It sits at or near the surface, in tissue we can physically access, load, and mechanically stimulate — and the biology backs up why that matters. Research on arthrofibrosis has found that the myofibroblast cells responsible for depositing excess collagen aren't permanently locked into that identity; under the right conditions, they can reverse differentiation back toward a quieter, non-scarring state. A 2025 review on exercise and tissue fibrosis found that mechanical loading actively downregulates TGF-β signaling and helps rebalance the enzymes that build up versus break down collagen matrix — not just in muscle, but across fibrotic tissue generally. And a 2026 review on fascial-targeted mechanical intervention described exactly how more targeted, higher-intensity mechanical input — the kind used in manual adhesion release and shockwave therapy — generates localized stress that disrupts fibrotic cross-links directly and triggers a fresh round of collagen turnover, giving tissue the chance to remodel back toward its normal, mobile structure.

In plain terms: the same cells that built the adhesion can, under the right mechanical input, help dismantle it. That's simply not true yet for fibrosis in most other organs of the body.

The honest caveat: fixable doesn't mean automatic

None of this means every case of adhesion resolves the same way, or that more mechanical input is always better. The exercise-and-fibrosis research above included a real caveat: excessive or poorly dosed loading can worsen fibrosis rather than reverse it, the same way an overly aggressive return to activity can re-injure a tendon that was just starting to remodel. Arthrofibrosis research also distinguishes between "active" cases, where inflammation and collagen deposition are still ongoing, and "residual" cases, where the fibrotic process has already burned out but the joint remains mechanically stiff — and those two states likely call for different approaches. Fixable, in other words, means responsive to the right kind of mechanical input, delivered in the right amount, at the right stage — not something that resolves on its own through generic stretching or waiting it out.

What this means for how we treat almost everything we see

If fibrous adhesion really is running underneath a large share of the musculoskeletal conditions we diagnose separately, it reframes what an evaluation is actually looking for. It's less "which named condition does this match" and more "where has tissue lost its normal glide, and what combination of manual release, targeted shockwave, or movement-based loading will most effectively restore it." That's the thinking behind treating each case as its own combination of tools rather than a one-size-fits-all protocol matched to a diagnosis code.

If you've been dealing with stiffness, restricted movement, or pain that's outlasted the original injury by months or years, there's a reasonable chance adhesion is playing a bigger role than whatever name has been put on it. Request an appointment and we'll look at what's actually restricting the tissue — not just what it's been called.