∙ In order to be eligible to participate in this study, subjects must meet all of the following criteria:

• Presenting with a Stage IV pressure ulcer requiring treatment of excision, bony debridement and flap coverage/primary closure.

• Operative candidate for flap surgery or primary closure.

• Presence of focal osteomyelitis as suggested by imaging to show extent of infection. Acceptable imaging techniques are Magnetic Resonance Imaging or CT scan.

• Adults ≥ 18 years in age at the time of treatment.

• Psychosocially, mentally, and physically able to fully comply with this protocol, including adhering to scheduled visits, treatment plan, completing forms, and other study procedures.

• Ability of the subject or legal authorized representative to provide voluntary, signed and dated informed consent prior to any study-related procedures.

∙ Subjects who meet any of the following criteria will be excluded from participating in this study:

• Reasons contributing to pressure ulcer cannot be addressed.

• Severe immunological compromised patients as determined by the clinician.

• Patients with diffuse or widespread pelvic osteomyelitis that is not amenable to adequate margins for debridement.

• Patients presenting with head pressure ulcers.

• Current or recent history (within last 2 years) of active substance abuse (e.g., recreational drugs, narcotics, or alcohol) that in the judgement of the investigator, may compromise the participant's safety/recovery or ability to follow the trial procedures.

• Current smoker.

• Diabetic patient with Hba1C level above 9.

• Allergy to any component of the investigational product, such as calcium sulfate, glycopeptide antibiotics (Vancomycin), or aminoglycoside antibiotics (Gentamicin).

• Concurrent involvement in a study of another investigational product.

⁃ Pregnant or planning to become pregnant during study period.

⁃ Flexion contractures where patient cannot passively get full extension.

⁃ Uncontrolled muscle spasms.

⁃ Unable to comply with bedrest restriction or offloading requirements

⁃ Unable to provide consent.

⁃ Fecal or urinary incontinence with contamination of the wound.

⁃ Lower extremity pressure ulcer location that is vascularly compromised as defined by an Ankle Brachial Index ≤ 0.7 mm Hg OR toe brachial index ≤ 0.6 mm OR toe pressure ≤ 40 mm Hg OR transcutaneous oximetry ≤ 40 mm Hg \*

⁃ Investigator considers the participant to be clinically malnourished.

⁃ Any conditions with known hypercalcemia (\> 10.3 mg/dl) or posing a significant risk for developing hypercalcemia (i.e., Hyperparathyroidism).

⁃ Investigator believes trial participation may compromise safety of the participant or trial results.

‣ Patients presenting with lower extremity pressure ulcers that are vascularly compromised can be rescreened followed successful revascularization