Reverse Ossification

This study seems like a game changer but unfortunately it's in persian:

Growth Plate Reappearance after Closure in Ankle Radiography for Trauma

"Bone growth plates or physis are present at the end of long bones and are responsible for longitudinal growth. These plates consist of 4 layers and are lucent in radiography as a line perpendicular to the longitudinal axis, Because of cartilage layer x-ray absorption is less than calcified bone. Gradually increases with age and bone maturity these line will be narrower and as longitudinal bone growth stops, the line disappears. This phenomenon occurs at different ages in different bones of the skeleton but with complete maturity at the age of 19, all growth plates are closed and sclerosed. Re-appearing after closing is uncommon. We introduce two young patients in this study due to trauma have been treated for an ankle cast and the growth plates of tibia and fibula in their control X-ray was re-appeared. Subchondrel Bone Resorbtion is a known phenomenon that will occur after 6 to 8 weeks immobility in any bone. The lucent line caused by imbalance in osteoblast and osteoclast activity and bone absorption. Re-appearing of growth plates can be caused by reversed ossification and bone absorption."

Masoud Mahmoudi Azar is the author of this study.  His follow up papers have no insight.
The cited studies may lead to clues on reversed ossification but I could not get access to them:

Effects of tiludronate on bone loss in paraplegic patients

The other links I could find don't seem to have a direct relation to reverse ossification just bone resorption.

Please help out if you know Persian or are an expert at translation documents(Google Translate doesn't like multiple columns).

Some selected translations(manually copying and pasting):

Figure 1: The graph occurs when the ankle and a half before casting

Figure 2: X-ray of the ankle occurred and half occurred after casting

Figure 3: X-ray event occurring half calf 78 days after casting

Figure 6: X-ray of the ankle occurred and half occurred after treatment

Figure 7: The graph and profile ankle occurred 45 days after treatment

Figure 4: X-ray of the ankle occurred before casting

Figure 5: X-ray of the ankle profile

Some notes in my feeble attempts to translate:

"The resurgence of growth plate can be absorbed by tissue"

"Treatment, the growth plates of the tibia and fibula appeared again."

"Patients can reverse the growth plate of the bone at the growth plate cartilage of the past"

What is subchondral bone resorption exactly?

Here's one of the cited studies:

Bone hyperemia precedes disuse-induced intracortical bone resorption

Hyperemia is an increase in blood flow

"An in vivo model was used to determine whether bone hyperemia precedes increased intracortical porosity induced by disuse. Twenty-four adult male roosters (age 1 yr) were randomly assigned to intact-control, 7-days-sham-surgery, 7-days-disuse, and 14-days-disuse groups. Disuse was achieved by isolating the left ulna diaphysis from physical loading via parallel metaphyseal osteotomies. The right ulna served as an intact contralateral control. Colored microspheres were used to assess mid-diaphyseal bone blood flow. Bone blood flow was symmetric between the left and right ulnae of the intact-control and sham-surgery groups. After 7 days of disuse, median (+/-95% confidence interval) standardized blood flow was significantly elevated compared with the contralateral bone (6.5 +/- 5.2 vs. 1.0 +/- 0.8 ml x min-1 x 100 g-1; P = 0.03). After 14 days of disuse, blood flow was also elevated but to a lesser extent. Intracortical porosity in the sham-surgery and 7-days-disuse bones was not elevated compared with intact-control bones. At 14 days of disuse, the area of intracortical porosity was significantly elevated compared with intact control bones (0.015 +/- 0.02 vs. 0. 002 +/- 0.002 mm2; P = 0.03). We conclude that disuse induces bone hyperemia before an increase in intracortical porosity. The potential interaction between bone vasoregulation and bone cell dynamics remains to be studied."

"altered bone blood flow was [likely] achieved by an endothelial cell-mediated process. Endothelial cells are sensitive modulators of local flow states and accomplish this process by expressing vasoactive substances"

"disuse would presumably decrease the metabolic demand of the cells within the tissue and would therefore result in decreased bone blood flow. Alternatively, mechanical loading may serve a vital role in ensuring that cells within bone (particularly osteocytes) receive sufficient metabolic exchange"


The role of subchondral bone resorption pits in osteoarthritis: MMP production by cells derived from bone marrow

"The vascular invasion of bone marrow tissue into the subchondral plate is often observed in articular cartilage and we named it the subchondral bone absorption pit; however, its implication in the pathogenesis of osteoarthritis (OA) has been poorly understood. The purpose of this study was to evaluate its characteristics and roles in osteoarthritic conditions.

Articular cartilage specimens from 11 patients with medial type knee OA and 7 non-arthritic cadavers were analyzed with HE staining. OA sections were stained with safranin-O, TRAP (tartrate resistant acid phosphatase) and immunostained with anti-MMP-1, MMP-3, MMP-13, vitronectin receptor (VNR)-alpha chain, vimentin and bone morphogenic protein (BMP) 2/4 antibodies.

Subchondral bone resorption pits were classified according to the extent of invasion: pits with bone marrow tissue were located within uncalcified cartilage below the tidemark in grade I and invaded beyond the tidemark in grade II, while no invasion was seen in grade 0. Grade II pits were dominant in OA compared to non-arthritic joints, especially medial condyles. Proteoglycan detected with safranin-O staining was lost around the tip of grade II pits and the density of pits was related to the modified Mankin Score. Cells in pits expressed vimentin, MMP-1, MMP-3 and MMP-13. Some polynuclear cells co-expressed VNR-alpha chain and MMP-13, whereas pits showed reparative features expressing BMP.

These results suggest that subchondral bone resorption pits contribute to cartilage degradation by expressing matrix metalloproteinases in OA."

"(A) Grade 0: subchondral plate with no invasion of bone marrow. (B) Grade I: subchondral bone resorption pit formation is limited within the calcified cartilage, (C) Grade II: bone marrow tissue infiltrate into the articular cartilage beyond the tidemark. Arrow: tidemark, AC: articular cartilage, CC: calcified cartilage, SB: subchondral bone, bar=100 μm."