The assessment of rotator cuff tear prior to shoulder replacement is based on the physical findings and imaging procedures, preferably magnetic resonance imaging (MRI). However, MRI is not always available, and in trauma patients, the CT-scan-based classification of glenohumeral arthritis or tendon damage is generally not applicable. In case of 4-part dislocated proximal humerus fractures the right diagnosis is crucial prior to choose between different type protheses or osteosyntheses. Therefore, there is a need for novel methods for the evaluation of rotator cuff damage. Our aim was to evaluate whether differential scanning calorimetry (DSC) could determine the grade of rotator cuff damage in patients undergoing shoulder replacement. Small samples of rotator cuff tendons of patients undergoing reversed shoulder replacement due to orthopedic or trauma indications were resected during surgery, and thermal parameters were measured using DSC. Radiological evaluation was also performed to classify the degree of rotator cuff damage and glenohumeral arthritis. In case of orthopedic samples, the consequence of advanced tendon damage was well demonstrated by the shape and the running of the curves, compared to the control sample. In trauma samples, the moderately degenerated tendons also exhibited significant difference from the control in the shape of the scans and in the thermal parameters. DSC curves demonstrated a clear difference in the thermal parameters of healthy and pathologic samples. DSC could be a useful additional method in the evaluation of rotator cuff tear arthropathies in future studies.

Shoulder replacement is a viable surgical treatment for comminuted proximal humerus fractures and shoulder osteoarthritis. Proper evaluation of hyaline cartilage is essential for the right choice of prosthesis; however, there are only a limited number of studies available investigating the cartilage of glenohumeral joint of patients undergoing shoulder replacement. We hypothesized that differential scanning calorimetry (DSC) could determine the grade of cartilage damage in patients undergoing reversed shoulder replacement, providing insights into the structural changes of the human cartilage samples. Sample of hyaline cartilage of glenohumeral joint was harvested during reversed shoulder replacement of orthopaedic and trauma patients. Thermal parameters were measured using DSC, and radiological examination of glenohumeral joint was also done prior to surgery. We have found that changes in thermal characteristics and DSC scans clearly indicate the severity of osteoarthritis and cartilage damage. The denaturation temperature range and the half-width of the heat flow curves were significantly wider in the orthopaedic samples compared to the control and traumatic ones. The calorimetric enthalpy (ΔHcal) exhibited significant differences in both pathologic samples, compared to the control. The melting temperatures (Tm) show that structural change caused by orthopaedic condition is greater than the effect of traumatic. Therefore, differential scanning calorimetry could help to determine the grade of cartilage damage in orthopaedic and trauma patients undergoing reversed shoulder replacement.

Prior to shoulder replacement, the quality of cancellous bone stock of humerus head should be evaluated. Thermogravimetric analysis (TGA) has already been utilized to assess thermal stability of cancellous bone mineral, collected from the femoral head of patients with osteoarthritis and osteoporosis. Our workgroup has recently examined the thermal parameters of rotator cuff of patients undergoing reversed shoulder replacement. We hypothesized that TGA of humerus head would indicate difference in the bone quality of orthopedic and trauma patients. We also hypothesized that the calorimetric data could correlate with the grade of degenerative changes. Cylindrical subchondral humeral head samples were collected from patients subjected to reversed shoulder replacement due to orthopedic or trauma indications. Then, calorimetric parameters were measured using DTA/TG analysis. Radiological evaluation was also performed to classify the grade of osteoarthritis. In case of orthopedic samples, the calorimetric parameters indicated a moderate to severe degree of bone damage and loss of mineralization, because of the progressed osteoarthritis. Meanwhile, the trauma samples exhibited only moderate or minimal subchondral bone degeneration. DTA curves showed different patterns and indicated shifts in transition temperatures, comparing control and pathologic samples. In addition, correlation was found between the degree of osteoarthritis and calorimetric enthalpy. DTA/TG analysis of humerus head samples indicated marked differences in bone quality of orthopedic and trauma patients. Further investigation is needed to differentiate the calorimetric parameters of different layers of subchondral bone.

Despite advanced imaging techniques, more information on the extent of joint degeneration and modifications in tendon collagen content is required for selecting the appropriate type of shoulder prosthesis. The goal of this study was to compare the thermal parameters of various tissue samples from patients who had shoulder arthroplasty and to correlate the thermal shifts with the outcomes of radiological and histopathological assessments. Rotator cuff (ROC) tendon, hyaline cartilage, and subchondral bone samples were obtained throughout surgery for a comminuted 4-part proximal humerus fracture or cuff tear arthropathy. Thermal parameters were measured using differential scanning calorimetry and thermogravimetry (DTA/TG). ROC: The effect of advanced collagen damage was visible in denaturation curves of osteoarthritis samples. Only moderately increased thermal enthalpy and melting temperature were found in the tissue of the trauma patients. Cartilage: Thermal parameters revealed that structural change generated by pathologic conditions exceeded the effects of trauma. Bone: Thermal parameters from degenerative samples revealed more structural damage and calcification decrease than thermal parameters from trauma samples. Correlation: A statistically significant relationship between the extent of osteoarthritis and the thermal variables of cartilage and subchondral bone was discovered. Authors suggest that thermal analysis may be useful in the diagnostic process of orthopedic and posttraumatic shoulder diseases.

Most commonly occurring in elderly patients, the comminuted 4-part or Neer VI type proximal humerus fractures frequently necessitate complete shoulder replacement. Despite the recent advances in imaging technologies, there is still a need for more information about the degree of joint degeneration and changes of the collagen content of tendons to select the proper implant type. It is known that human long head biceps tendon subjected to synovial inflammation and mechanical wear could result in tear and structural damage. Differential scanning calorimetry has already been demonstrated to be a dependable in the assessment of collagen in degenerative tendon conditions. The purpose of the study was to determine whether variations in thermal parameters detected by DSC are related to the degenerative changes of LHBT samples. LHBT tendons were collected from patients who had reversed shoulder arthroplasty because of trauma. DSC was utilized to measure the thermodynamic changes. Macroscopical, radiological and histological assessment were also performed. Based on the thermal parameters and denaturation curves, LHBT samples collected of patients underwent reversed shoulder arthroplasty due to comminuted proximal humerus fracture have shown minimal or mild degenerative injuries. These data were supported by preoperative radiological examination and histological analysis. The authors suggest that DSC could be a useful investigative tool in the clinical evaluation of tendon injuries.