Minimally Invasive Percutaneous Fixation with the Palm Tree Technique for fractures of the proximal humerus

Introduction: The optimal treatment of displaced proximal humeral fractures remains controversial.
We describe a modified minimally invasive technique using 3 curved wires, inserted in a retrograde fashion into the humeral head. These are aimed to diverge within the humeral head to provide 3 separate 3-point fixations to achieve good stability. The aim of this study is to present the experience of our unit in the management of proximal humerus fractures with this modified palm tree technique.

Methods: Prospective study of patients treated with the palm tree technique. Demographics, radiographs, complications and revision surgery data were collected and analysed. At the final follow up range of motion, subjective shoulder value and the Constant Score were recorded.

Results: Between 1998 and 2017, 130 patients underwent surgical fixation of their proximal humerus fractures with the modified palm tree technique. 95 were female and 35 male. Average age was 65 years (range 15 – 92). As per the Neer classification 57 fractures were 2 parts, 46 were 3 parts and 27 were 4 parts. Average follow up was 26 months (range 6 – 156 months). 4 patients had screws inserted for the tuberosity fragments. 33 patients had a bone substitute inserted for structural support. There were 11 revisions (8.4%) of metalwork. In 7 cases the palm tree failed and had to be revised early to other implants (2 locking plates, 2 angular plates, 1 reverse arthroplasty and 2 hemiarthroplasties) and in 4 cases the palm tree had to be revised in order to achieve better positioning and engangement of the wires. From the 123 remaining patients, 118 achieved union (95.9%) There were 3 painless fibrous non-unions and 2 painful non-union requiring revision to a plate and to a reverse arthroplasty system. The final constant score ranged between 14 and 100 with an average of 63. Subjective shoulder value at the last appointment was on average 7.8 (range 0 – 10). The final average range of motion was: Abduction 125^o (30^o -180^o), forward flexion 130^o (30^o – 180^o) and external rotation 48^o (0 – 90^o). In the united fractures there were 4 malunions (3.3%). 9 patients (6.8%) developed AVN and 3 out of them required arthroplasty surgery.

Conclusion: The palm tree is a simple, minimally invasive technique which can be used for 2, 3 and 4 part fractures with good functional outcomes and high union rates.