# Joint tissue plasticity in hemophilia: insights from the Joint Activity and Damage Exam ultrasound protocol

## TL;DR

This study uses ultrasound to track changes in hemophilic joints over time, revealing that tissue damage may be reversible, even in unhealthy joints.

## Contribution

The study introduces longitudinal ultrasound measurements to show dynamic tissue plasticity and potential repair in hemophilic joints.

## Key findings

- Unhealthy joints had thinner cartilage and more osteochondral changes at baseline.
- Tissue plasticity was observed in both healthy and unhealthy joints, suggesting possible reversibility of damage.
- Hemarthrosis was linked to cartilage thinning and increased PRO-C4 levels.

## Abstract

Progressive arthropathy is a debilitating condition that affects hemophilic joints as a consequence of hemarthroses. However, our understanding of the trajectory of potentially destructive processes at the tissue level remains limited and requires longitudinal imaging studies.

To longitudinally characterize ultrasonographic joint tissue changes in adults with hemophilia using the Joint Activity and Damage Exam (JADE) protocol, and to examine their relationships with joint health status, hemarthrosis, and serum biomarkers of tissue turnover.

We prospectively studied adults with hemophilia (A or B) of any severity and associated arthropathy at 3 North American sites. We assessed joint health using the Hemophilia Joint Health Score (HJHS) and musculoskeletal ultrasound, as well as the Joint Activity and Damage Exam protocol for direct measurements of osteochondral alterations, cartilage, and soft tissue in the elbows, ankles, and knees at study entry and at ∼12 to 18 and ∼24 to 36 months thereafter. Reported hemarthrosis between study visits was verified by musculoskeletal ultrasound. We analyzed tissue rate changes in healthy (HJHS 0-3) and unhealthy (HJHS ≥ 4) joints, as well as in joints with and without hemarthrosis. Associations between tissue measurements and serially obtained serum biomarkers (C4M, PRO-C4, and C3M) were explored using logistic regression.

The median age (N = 44) was 36.5 years. Joints (133 healthy and 131 unhealthy at baseline) were evaluated serially. Only 16 joints experienced at least 1 hemarthrosis. At baseline, unhealthy joints had significantly thinner cartilage and increased osteochondral alterations and soft tissue swelling (all P values < .001). While individual joint tissues followed either a positive or negative trajectory of expansion or contraction over the ensuing 2 to 3 years, mean rate changes were not significantly different between healthy and unhealthy joints. Hemarthrosis resulted in a predilection for cartilage thinning and positive rate changes in PRO-C4 (P = .006).

Ultrasonographic tissue measurements discriminated between healthy and unhealthy joints at baseline. Measurements revealed a dynamic pattern of tissue plasticity not only in healthy but also in unhealthy and bleeding joints, suggesting potential for reversibility of often-assumed irreversible intra-articular damage in hemophilic joints.

•The precise trajectory of tissue destruction and repair in hemophilic arthropathy is unknown.•Longitudinal evaluation was performed with musculoskeletal ultrasound (JADE protocol).•Tissue measurements demonstrated dynamic tissue plasticity, irrespective of joint health status.•Tissue measurements revealed unanticipated repair of assumed irreversible cartilage damage.

The precise trajectory of tissue destruction and repair in hemophilic arthropathy is unknown.

Longitudinal evaluation was performed with musculoskeletal ultrasound (JADE protocol).

Tissue measurements demonstrated dynamic tissue plasticity, irrespective of joint health status.

Tissue measurements revealed unanticipated repair of assumed irreversible cartilage damage.