Background: Humeral head fractures and their postoperative outcome remain a challenging problem in surgical daily routine. Predictive factors for loss of fixation are rare.
Objective: Determination of predictive factors for the failure of osteosynthesis with the loss of fixation or migration of screws in humeral head fractures.
Method: From 1995 to 2011, 408 patients with proximal humeral fractures [mean age 66.6 years, 50.9-82.3 years] and osteosynthesis were analyzed. Two hundred and three received open reduction internal fixation (ORIF) with the PHILOS® plate. The non-locking plate was used in 80, the locking plate in 16 and humeral head prosthesis in 26 patients, in addition to 23 patients undergoing other procedures. Intraoperative reduction that achieved an anatomical alignment of the medial aspect of the humerus (humeral calcar) was assessed in 94 patients by postoperative X-ray analysis. The loss of fixation was evaluated by a follow-up of three to five X-rays and measurement of the humeral tip-apex-distance (HTAD).
Results: For stable fixed fractures with an intact calcar, percentual HTAD was significantly higher than for unstable fixed fractures (p=0.04). Morbidity, such as hypertension, orthopedic operations or diabetes, strongly influenced the HTAD, while postoperative passive motion treatment modestly affected the HTAD over time.
Conclusion: The anatomic reconstruction of the calcar, leading to stable fixation of humeral head fractures, can significantly prevent an overproportioned decrease in the HTAD in postoperative X-rays and seems to be vital in multimorbid patients. Measurement of the HTAD over time delivers a tool for early detection of secondary loss of fixation.
Keywords: Calcar; HTAD; Humeral head fracture; Humeral tip-apex-distance; Loss of fixation; Philos® plate; Postoperative treatment.