The stability of percutaneous fixation of proximal humeral fractures

Focus on stability: biomechanical evaluation of external fixation technique versus locking plate osteosynthesis in 3-part proximal humeral fractures

BACKGROUND

The purpose of this study was to investigate the primary stability and displacement tendencies of an external fixation system in 2 different configurations in comparison to locking plate fixation in a 3-part proximal humeral fracture model.

METHODS

Twenty-one fresh-frozen human cadaveric proximal humeral specimens were divided into 3 groups of 7 stripped specimens. An unstable 3-part fracture of the proximal humerus was set. Construct A consisted of the Galaxy Fixation Shoulder System, with fixation in accordance with the manufacturer's recommended technique (3 pairs of threaded wires). Construct B was fixed with an additional pair of threaded wires according to the recommendations of Gumina et al (4 pairs of threaded wires). The remaining 7 specimens were fixed with a locking plate. By use of an optical motion capture system, relative motion at the fracture site and failure load were evaluated during a cyclic loading protocol.

RESULTS

Plate osteosynthesis showed the highest cyclic load to failure (895 ± 239 N; range, 597-1135 N), followed by construct B (692 ± 121 N; range, 432-788 N) and construct A (350 ± 190 N; range, 139-615 N). Statistically significant differences were found between plating and construct A (P < .001), between plating and construct B (P = .031), and between construct B and construct A (P = .013). Relative motion at the fracture site, in terms of change in distance during cyclic loading, was lowest with construct B measured at the peak load of 395 N after 11 steps (1.73 ± 1.98 mm; range, 0.53-5.96 mm) and highest with construct A (8.46 ± 10.67 mm; range, 2.26-20.79 mm). Angular change measured at the peak load after 11 steps was lowest with construct B (1.19° ± 0.36°; range, 0.59°-1.7°) and highest with construct A (2.44° ± 1.63°; range, 0.77°-4.04°). Statistically significant differences were found between construct A and construct B and between construct A and plating at various steps of cyclic loading.

CONCLUSION

In this biomechanical study of unstable 3-part proximal humeral fractures, locking plate osteosynthesis demonstrated the highest possible load application. External fixator application with 8 threaded wires (construct B) revealed the least relative motion at the fracture site, without a statistically significant difference compared with locking plates. It therefore represents another valid technique for treatment regarding primary stability. The use of external fixator application with 6 threaded wires (construct A) resulted in the lowest stability and the highest rates of displacement.

Outcomes of 188 Proximal Humeral Fractures Treated with a Dedicated External Fixator with Follow-up Ranging from 2 to 12 Years

BACKGROUND

The treatment of a displaced proximal humeral fracture is still a matter of controversy. Minimally invasive techniques are considered promising options. The purpose of this study was to report outcomes at medium to long-term follow-up after surgical treatment with pins stabilized with an external fixator.

METHODS

A total of 235 patients (average age, 64 years [95% confidence interval (CI), 62 to 65 years]) were treated with closed or open reduction and fixation with pins stabilized by an external fixator specifically designed for proximal humeral fractures. The pins were inserted using a "pins-crossing-fracture" or a "pins-bridging-fracture" technique. One hundred and eighty-eight patients had a minimum radiographic and clinical follow-up of 2 years. Outcomes were assessed using the Oxford Shoulder Score (OSS), the subjective shoulder value (SSV), a visual analog scale (VAS) for pain, and, for 155 patients, the Constant score.

RESULTS

Eighty-one (43%) of the 188 patients had a 2-part fracture, 60 (32%) had a 3-part fracture, and 47 (25%) had a 4-part fracture. The reduction was performed with percutaneous maneuvers in 120 shoulders or a deltopectoral approach, in 68. The external fixator was applied using a "pins-crossing-fracture" technique in 133 shoulders and using a "pins-bridging-fracture" technique in 55. At last follow-up, mean clinical scores were as follows: OSS, 42.6 (95% CI, 42 to 44); SSV, 85.5 (95% CI, 83 to 88); and VAS for pain, 1 (95% CI, 0.7 to 1.2). The complication rate at 3 months was 16% (37 of 235). The most frequent complication was pin-track infection (19 of 235, 8%). A total of 50 patients had ≥1 complication (50 of 188, 27%) and 6 (3%) underwent revision surgery. More complications were observed with the "pins-crossing-fracture" technique.

CONCLUSIONS

In our experience, the use of the external fixator has been a valuable option in the treatment of proximal humeral fractures. The complication and revision rates were acceptable. Most of the complications encountered were manageable without revision surgery.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

A comparative retrospective study of locking plate fixation versus a dedicated external fixator of 3- and 4-part proximal humerus fractures: Results after 5 years

INTRODUCTION

Fractures of the proximal humerus (PHF) represent a common injury among orthopedic department; especially for three- and four-part fractures no consensus about the best treatment is still achieved. The aim of our study was to compare clinical and radiological outcomes in patients alternatively treated with plates and screws or external fixation system for a type III-IV proximal humerus fracture.

MATERIAL AND METHODS

Sixty-nine patients went surgery for type III-IV PHF between January 2011 and January 2014. According to the Neer classification, fractures were classified as type III in 50 cases (72,46%) and type IV in 19 cases (24,56%). 45 patients were treated with plates (65%) and 24 external fixators (35%). The patients' mean age was 62 years (range, 31-87 y). At five years, 60 patients (86,9%) were assessed using the visual analog scale (VAS) pain score, Constant Score (CS), the range of motion, and radiological evaluation. The CS at five years was the primary outcome measure. Results were evaluated and compared with the contralateral unaffected side to avoid bias related to different ages.

RESULTS

At the final follow up, we found no clinical differences when comparing the two procedures. Moreover, when age was considered as a variable, a significative difference of the CS was observed in the group of patients younger than 65 years treated with a plate (Plate Group Mean: 79; SD: +/- 15. Ex Fi Mean: 58; SD:+/- 4. P = 0,008). In the group of patients older than 65 years, the two procedures did not show significative differences in outcomes (Plate Group Mean: 69; SD: +/- 15. Ex Fi Mean: 63; SD:+/- 7. P = 0,032). External fixation procedure was overall associated with a reduction in blood loss, surgical time, length of hospital stay.

CONCLUSION

Percutaneous techniques have a long tradition in PHF treatment; the introduction of dedicated external fixation system has the advantage to improve the stability and allow early rehabilitation when compared to the classical pinning technique. In our experience, the indication elderly patients with osteoporosis and comorbidities may benefit by this type of mini-invasive surgery with low soft tissue damages.

Low complication rates in Minimally Invasive Plate Osteosynthesis (MIPO) for proximal humeral fractures at 5 years of follow-up

INTRODUCTION

Purpose of this study was to analyse the medium term follow-up of minimally invasive plate osteosynthesis (MIPO) for proximal humeral fractures in terms of postoperative shoulder function, radiological outcome and complications.

METHODS

76 consecutive patients with unstable proximal humeral fractures were treated using locking plate with a minimally invasive antero-lateral approach in two surgical centers. Constant score and radiographic evaluation of 74 patients were available at mean follow up of 5 years (minimum 4 years).

RESULTS

Mean Constant score was 74 (range to 28-100). Results were comparable in the two centers. Younger patients registered significantly higher scores (p < 0.05). 20 patients (27%) developed complications. Subacromial impingement occurred in 16,2% of cases for varus malreduction (6,7%) and for too proximal plate positioning (9,5%). Primary screws perforation (2,7%), secondary perforation due to cut-out (1,4%), avascular necrosis (AVN) of humeral head (1,4%), partial resorption of greater tuberosity (2,7%), secondary displacement of the greater tuberosity (2,7%) and stiffness (2,7%) were observed.

DISCUSSION AND CONCLUSIONS

Even at a medium term follow-up, MIPO for proximal humeral fractures ensured good and reproducible results for most common pattern of fractures. Major complications were lower respect to open procedures, because of soft tissue, deltoid muscle and circumflex vessels sparing.

Effect of surgical delay on bacterial colonization in proximal humeral fractures

Postoperative infection is a severe complication after proximal humeral fracture surgical treatment. The aim of this study was to determine if the surgical delay could modify the number and type of bacteria on the surgical site. A two stages study was set up. In the first stage the effect of delay was simulated in 20 patients affected by proximal humeral fracture treated conservatively. In a second stage, the effect of delay was measured in 20 patients that underwent surgery. In stage 1, three skin culture swabs were taken in correspondence of the deltopectoral approach, the day of the fracture (day 0), the day after (day 1), and five days after fracture (day 5). In stage 2, skin swab cultures were taken the day of trauma and immediately before surgery and cultured on various media suitable for aerobic and anaerobic bacteria. The number of bacteria increased over the course of the study, from day 0 to day 5, both considering the total number of colony-forming units and individual species of pathogen bacteria. The second stage of the study confirmed these data. An increasing number of bacteria was observed in patients that underwent surgery later than 2 days from trauma. The delay of surgery increased bacterial colonization of the skin in the deltopectoral approach area including common pathogenic bacteria such as Staphylococcus aureus, coagulase-negative staphylococci and Propionibacterium acnes. This might justify the correlation between delay to surgery and risk of infection. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:942-948, 2016.