Samilson and Prieto described the glenohumeral arthropathy seen on radiographs after anterior or posterior shoulder dislocation and looked for factors related to its severity.
Consultation series of 74 shoulders in 70 patients, all initially treated elsewhere, so incidence could not be estimated. Contralateral shoulder radiographically normal in every patient with a unilateral dislocation.
Active external rotation and abduction with the arm at the side
Key Findings
Moderate or severe arthrosis developed in 10 of 11 posteriorly dislocated shoulders vs 19 of 62 anteriorly dislocated ones, and the authors suggested that delayed diagnosis may explain the difference.
Recurrence did not drive severity: 15 of 21 shoulders with a single dislocation had moderate to severe arthrosis vs 14 of 53 (26%) with recurrent dislocations.
Moderate to severe arthrosis was found in 16 of 29 unoperated shoulders (55%) vs 13 of 45 operated shoulders (29%).
All 7 shoulders in which internal fixation metal penetrated the joint cartilage had moderate (2) or severe (5) arthrosis.
Glenoid rim or humeral head defects were not related to how severe the arthrosis was.
Board pearl
Samilson‑Prieto grading rests on the height of the inferior humeral or glenoid exostosis on the AP radiograph, with cut‑offs at 3 mm and 7 mm.
Samilson‑Prieto dislocation arthropathy gradesSamilson, J Bone Joint Surg Am 1983Modified from Hindmarsh, Acta Orthop Scand 1967
Mild
Inferior humeral or glenoid exostosis under 3 mm on the AP radiograph
None of the 45 shoulders had symptoms, and external rotation averaged 62°.
Moderate
Exostosis 3 to 7 mm with slight glenohumeral joint irregularity
All 14 shoulders had symptoms (pain, crepitus, limited motion), and external rotation averaged 23°.
Severe
Exostosis over 7 mm with glenohumeral narrowing and sclerosis
All 15 shoulders had symptoms, and external rotation averaged 14°.
External rotation in the uninvolved shoulder averaged 73°.
Authors' conclusion
Operations in which internal fixation devices intruded on joint cartilage frequently resulted in moderate to severe arthrosis.
Samilson and Prieto described the glenohumeral arthropathy seen on radiographs after anterior or posterior shoulder dislocation and looked for factors related to its severity.
Consultation series of 74 shoulders in 70 patients, all initially treated elsewhere, so incidence could not be estimated. Contralateral shoulder radiographically normal in every patient with a unilateral dislocation.
Active external rotation and abduction with the arm at the side
Key Findings
Moderate or severe arthrosis developed in 10 of 11 posteriorly dislocated shoulders vs 19 of 62 anteriorly dislocated ones, and the authors suggested that delayed diagnosis may explain the difference.
Recurrence did not drive severity: 15 of 21 shoulders with a single dislocation had moderate to severe arthrosis vs 14 of 53 (26%) with recurrent dislocations.
Moderate to severe arthrosis was found in 16 of 29 unoperated shoulders (55%) vs 13 of 45 operated shoulders (29%).
All 7 shoulders in which internal fixation metal penetrated the joint cartilage had moderate (2) or severe (5) arthrosis.
Glenoid rim or humeral head defects were not related to how severe the arthrosis was.
Board pearl
Samilson‑Prieto grading rests on the height of the inferior humeral or glenoid exostosis on the AP radiograph, with cut‑offs at 3 mm and 7 mm.
Samilson‑Prieto dislocation arthropathy gradesSamilson, J Bone Joint Surg Am 1983Modified from Hindmarsh, Acta Orthop Scand 1967
Mild
Inferior humeral or glenoid exostosis under 3 mm on the AP radiograph
None of the 45 shoulders had symptoms, and external rotation averaged 62°.
Moderate
Exostosis 3 to 7 mm with slight glenohumeral joint irregularity
All 14 shoulders had symptoms (pain, crepitus, limited motion), and external rotation averaged 23°.
Severe
Exostosis over 7 mm with glenohumeral narrowing and sclerosis
All 15 shoulders had symptoms, and external rotation averaged 14°.
External rotation in the uninvolved shoulder averaged 73°.
Authors' conclusion
Operations in which internal fixation devices intruded on joint cartilage frequently resulted in moderate to severe arthrosis.