Purpose: We searched to define a fracture index useful for predicting the risk of bone fracture in children with essential bone cysts.

Material and method: We reviewed 96 children with an essential bone cyst. The following clinical data were recorded: age, cyst localisation, circumstances of diagnosis.

The radiological analysis was based on 193 AP and lateral x-rays. We measured: 1) the distance separating the superior pole of the cyst from the suprajacent growth cartilage, 2) the largest cyst diameter, 3) the greatest cyst height, 4) the thinnest cortical width facing the cyst, 5) the cyst surface area calculated exactly using surface area software and expressed as a a ratio of shaft diameter (S/d2, Kaelin index). These different parameters were compared for cysts associated with fracture or not.

Results: Mean age at diagnosis was 10.4 years (range 2 – 12.8 years). Most of the cysts were located in the upper portion of the humerus (72%). Fracture was the inaugural sign in 68% of the cases.

Comparing the two cohorts of patients demonstrated that the following differences were significant (Student’s t test): 1) cyst width (p=0.0038): below 16 mm none of the cysts fractured. For wider cysts, there was no difference between the fracture and non-fracture cysts. 2) cortical thickness (p=0.0002); cortical thickness greater than 5 mm protected against fracture. If the cortical measured less than 3 mm, the risk of fracture was greater than 50%. 3) Kaelin index: (p< 0.0001) was directly correlated with fracture risk but no cutoff could be identified.

For an 80 – 100% risk of fracture, the cyst must have the following characteristics: width > 30 mm, height > 75 mm, cortical thickness < 2.4 mm, Kaelin index > 5.

For a 50% risk of fracture, the cyst must have the following characteristics: width > 24 mm, height > 55 mm, cortical thickness < 3 mm, Kaelin index > 3.

Conclusion: The Kaelin index is reliable but difficult to calculate in the consultation setting. Cortical thickness is a good indicator. Its predictive value can be improved by correlating the height of the cyst with its width. These measure can be obtained easily during consultation.

Purpose: Fractures of the upper humerus are frequent in elderly persons. While 80% are generally treated orthopaedically, about 20% are complex complicating treatment. Osteosythesis has given disappointing results due to the poor bone quality. Simple humeral arthroplsaty with simple tuberosity fixation could be a solution.

Material and method: Between 1993 and 1998, 50 patients, 39 women and 11 men, mean age 74.5 years (51–90) were treated for cephalotuberosity fractures with cemented humeral arthroplasty. The dominant side was involved in 80% of the cases; there were 39 fractures with four fragments in the Neer classification with seven associated with anterior dislocation, eleven with three fragments including two associated with anterior dislocation. Three patients had a neurological complication: elongation of the brachial plexus in one and irritation of the ulnar nerve in two. Mean delay to surgery was 2.4 days. Thirty-seven patients were operated via the superolateral approach, 13 via the deltopectoral approach. A total of 37 Neer prostheses were implanted and 13 Guepar prostheses. Three patients had a full thickness cuff tear, sutured in the same operative time. The glenoid cavity was healthy in all cases. the upper limb was immobilised elbow against thorax using an abduction brace for 2& days. Active rehabilitation exercises began during the sixth week.

Results: Mean follow-up was 2.5 years. Twelve patients had died, four were lost to follow-up and six could not be examined due to an alteration of their cognitive functions. The analysis thus concerned 28 patients. The mean absolute Constant score at last follow-up was 47 points, with a weighted score of 70 points. Outcome was good in nine cases, fair in eight, and poor in eleven. 86% of the shoulders were pain free. Overall active mobility was: antepulsion 80.5°, abduction 77°, external rotation 20°; 18 patients had internal rotation at L5or more. Radiographically, there was a tuberosity lysis in eight patients and a defective trochiter callus in nine. No changes in the humeral component cementing were observed. The trochiter lever arm was 28 cm, 92.7% of the offset measured on the healthy side. The distance between the apex of the head and the trochiter was 10 mm on the average. Glenoid wear was noted in ten cases. There was no evidence of periprosthetic ossification. Mean ES was 9.9 mm.

Discussion: Pain relief was good. Amplitudes were correlated with age, the quality of the tuberosity fixation, and the duration of rehabilitation (> 1 year). An associated dislocation did not appear to have a deleterious effect. The approach used or offset did not appear to affect results.

Conclusion: Our patients achieved good pain relief but lost a certain degree of mobility, similar to findings reported in the literature. The main prognostic factors are the quality of the tuberosity reconstruction and patient compliance to rehabilitation.