Cross-elements to enhance fixation in osteoporotic bone with application to proximal humeral locking plates: a biomechanical study

Proximal humeral fractures treated with a low-profile plate with enhanced fixation properties

BACKGROUND

Our purpose was to evaluate the clinical and radiographic outcomes of proximal humeral fractures treated with a new generation plating system and compare results with a meta-analysis of recent literature.

METHODS

Between 2014 and 2017, 93 patients (18 males, 75 females) with proximal humerus fractures were treated with open reduction and internal fixation (ORIF) using a Pantera® Plate. These low-profile plates are anatomically shaped and include "cross-elements" that form a three-dimensional scaffold in bone to enhance fixation stability. According to Neer classification, there were 24 two-part fractures, 49 three-part fractures and 20 four-part fractures (4 with dislocated heads). X-rays and Constant Shoulder Scores (CSS) were used to evaluate healing, complications, and clinical outcomes. Results were compared with a meta-analysis of similar studies reported in literature over the last 10 years.

RESULTS

Eighty-three patients with a minimum follow-up of 2 years had a mean CSS of 72 (53-90) graded as excellent for 23 patients (28%), good for 35 (42%), fair for 14 (17%), and poor for 11 (13%). Fractures healed without complication in 75 (91%) patients. Eight (9%) complications were observed, i.e., three avascular necrosis of the humeral head, one case of implant loosening, two cases of subacromial impingement and two superficial infections. There was no significant correlation between Neer fracture stage and patient outcome (p = 0.257). Compared to the literature, this method had a lower complication grade (p = 0.03), though it did not significantly differ in its clinical outcomes (p = 0.08).

CONCLUSIONS

The investigated plating system includes design features that can potentially increase utility for ORIF of proximal humeral fractures. While the complication profile was signficantly less than reported in the literature for standard proximal humerus plates, clinical outcomes were similar. Further studies will be required to better understand the role of plate design on treatment of these challenging fractures.

LEVEL OF EVIDENCE

IV, therapeutic study.

The forgotten fragment: additional lesser tuberosity fixation of 4-part proximal humeral fractures-a biomechanical investigation

BACKGROUND

Fractures of the proximal humerus are common. The most frequent surgical treatment option is open reduction and locking plate fixation. Multifragmentary fractures, including 3- and 4-part fractures, are especially challenging to treat because they correlate with an increased risk of fixation failure. In the past, several mechanisms of additional fixation were investigated, but none directly addressed the lesser tuberosity (LT). The goal of this study was to investigate the biomechanical impact of additional anterior fracture fixation in lateral locked plating (LLP) of 4-part proximal humeral fractures (PHFs).

METHODS

Twenty-seven fresh frozen human shoulder specimens (mean age, 80 years) with intact rotator cuffs (RCs) were randomized into 4 groups: 3-part PHF with LLP and RC cerclage (n = 6); 4-part PHF with LLP and RC cerclage as standard of care (n = 7); 4-part PHF with LLP, RC cerclage, and 2 anterior 3.5-mm cortical screws (n = 7); and 4-part PHF with LLP, RC cerclage, and additional anterior one-third tubular plate (additional anterior plating [AAP], n = 7). Static load of the RC was simulated with weights. A force-controlled cyclic loading test was performed with a servo-hydraulic testing machine, followed by load-to-failure testing. An optical motion capture system recorded humeral head range of motion.

RESULTS

LLP of a 4-part PHF showed more humeral head motion than LLP of a 3-part PHF without fracture of the LT (P < .001). Fixing the LT to the humeral head with two 3.5-mm screws significantly reduced humeral head motion compared with LLP with RC cerclage alone (P < .006). Using AAP significantly increased the construct stiffness compared with the standard of care (P = .03).

CONCLUSION

LLP of a 4-part PHF is biomechanically less stable than LLP of a 3-part PHF without fracture of the LT. Additional screw fixation of the LT in 4-part PHFs improves stability compared with LLP alone. In case of metaphyseal comminution, AAP is favorable from a biomechanical perspective.

No change in outcome ten years following locking plate repair of displaced proximal humerus fractures

PURPOSE

To assess longer-term (> 5 years) function and outcome in patients treated with anatomic locking plates for proximal humerus fractures.

METHODS

This retrospective cohort study was conducted at an urban, academic level 1 trauma center and an orthopedic specialty hospital. Patients treated operatively for proximal humerus fractures with an anatomic locking plate by three orthopedic trauma surgeons and two shoulder surgeons from 2003 to 2015 were reviewed. Patient demographics and injury characteristics, disabilities of the arm, shoulder, and hand (DASH) scores, complications, secondary surgeries, and shoulder range of motion were compared at 1 year and at latest follow-up.

RESULTS

Seventy-five of 173 fractures were eligible for analysis. At a minimum 5 years and a mean of 10.0 ± 3.2 years following surgery, DASH scores did not differ from one-year compared to long-term follow-up (16.3 ± 17.4 vs. 15.1 ± 18.2, p = 0.555). Shoulder motion including: active forward flexion (145.5 vs. 151.5 degrees, p = 0.186), internal rotation (T10 vs. T9, p = 0.204), and external rotation measurements (48.4 vs. 57.9, p = 0.074) also did not differ from one year compared to long-term follow-up. By one year, all fractures had healed. After 1-year post-operatively, four patients underwent reoperation, but none for AVN or screw penetration.

CONCLUSIONS

Patient-reported functional outcome scores and shoulder range of motion are stable after one year following proximal humerus fracture fixation, and outcomes do not deteriorate thereafter. After one-year, long-term follow-up of fixed proximal humerus fractures may be unnecessary for those without symptoms.