In this retrospective study postoperative subscapularis (SSC) function was measured with an electronic force measurement plate (FMP) and clinical scores and correlated with SSC-muscle cross sectional area on defined MRI-sequences.

82 patients with subscapularis tears (34 isolated SSC tears and 48 combined SSC/SSP tears) were followed up at a mean of 38 (24–72) months after tendon reconstruction with the Constant score (CS) and clinical SSC-tests (Napoleon test, Lift off test). SSC-muscle function was assessed in the belly-press- and the lift off position using a custom made electronic FMP (force in Newton). SSC muscle strength values were compared with the contra-lateral side. SSC-muscle atrophy (muscle cross sectional area in mm²) was measured on standardised sagittal MRI-planes and compared with a healthy matched control group (CG) (Mann-Whitney-U-Test).

The mean CS improved from 51p to 81p in isolated tears (group 1) and from an average 47 p to 78 p in combined tears (group 2) (each p< 0.01). Overall 85% of the patients rated their result as good or excellent. Positive and intermediate postop. Napoleon tests were still present in 30% in group 1 and in 25% in group 2. Mean postoperative SSC-muscle strength in the belly-press position averaged 64 N (contralatera sidel-CL: 86 N) in group 1 and 81 N (CL: 91 N) in group 2. Lift-off test strength averaged 36 N (CL: 69 N) in group 1 and 50 N (CL: 63 N) in group 2 (each p< 0.05). Postoperative MRI revealed a significant reduced SSC muscle cross sectional area for the operated side compared with the CG (group 1: SSC: 1974 mm²; CG 2980 mm² p< 0,05; group 2: SSC: 1829 mm²; CG 2406 mm² − SSP: 570 mm²; CG 812 mm² each p< 0,05).

Despite good clinical results after reconstruction of isolated and combined subscapularis tears a marked subscapularis strength deficit remains that is not reflected in the Constant Score, but can be detected with the new measurement device. Additionally a subscapularis muscle atrophy remains in the postoperative course that cannot be reversed by surgery.

The pathogenesis of Calcifying Tendinitis (CT) is still not well established. Prognostic factors for outcome could not yet be identified. The purpose of this study was to evaluate the histologic features of calcific deposits (CD) and their correlation with radiologic and clinical findings.

122 patients with a radiologically confirmed CD were prospectively scheduled for arthroscopic shoulder surgery. According to their radiologic appearance (RA) the CD were graded as fluffy or sharply demarcated. Arthroscopic removal of the deposit was performed and biopsies were taken and embedded in methylmethacry-late. Sections were stained and also immunohistology was performed. Shoulder function was assessed with the Constant score (CS) and the SST.

Three distinct histologic stages (HS) of the CDs could be divided: calcification (I), fibrotic organisation (II) and ossification (III). Biopsies revealed 42x (34%) HS I, 18x (15%) HS II and 62x (51%) HS III deposits. 90% of the CD were located in the SSP tendon. 12 months after the operation the CS and the SST showed a significant improvement (p< 0.01). Forty percent of the patients with ossification (III) of the CD underwent unsuccessful shock wave therapy before. The preoperative RA as well as the HS of the CD did not predispose to postoperative outcome.

In this study three definite histologic stages of Calcifying Tendinitis were identified that have not been described previously. We underline the hypothesis that CT is an active cell mediated tissue process which can lead to production of primitive bone.