Proximal humerus fractures are often brought on by osteoporosis and typically result from mild trauma. Proximal humeral fractures have become more common in Germany in recent years, with an expected 60 thousand new cases in 2022 alone. As the global population ages, we might anticipate a similar rise in the prevalence of proximal humeral fractures.¹

When there are good surgical indications for it, the standard deltopectoral approach is used to plate repair displaced fractures of the proximal humerus. The lateral aspect of the humerus, according to some authors, must be exposed by extensive soft tissue dissection and muscle retraction. A deltoid split method has been proposed to lessen the impact on the surrounding soft tissues. Early results have been reported, despite the fact that only a limited number of nonrandomized trials have compared this approach to others. We conducted a randomized scientific test to fill in the blanks left by the existing literature.^2-3

We hypothesized that the complication rate, arm function, and patient comfort would all be better with a deltoid-split approach to open reduction and internal fixation of humeral proximal fractures using such a polyaxial locking device than with a deltopectoral approach.⁴

Clinical Samples

Our facility performed 223 cases of plate osteosynthesis for proximal humerus fractures between December 2019 and October 2022. Thirty-two fractures, including dislocations and those with associated vascular injuries, were treated with a delta-pectoral approach. Among the 223 patients with fractures, 67 were unable to be assessed because of their international residence, 2 died for reasons unrelated to the surgery, 7 did not want to have outpatient visits because they lived in a nursing home, 5 were lost to follow-up, or 13 declined evaluation. For 97 fractures with at least a year of follow-up data, we have complete prospective data. Our series includes procedures done by 16 different surgeons, each of whom did anything from one to twenty-eight procedures.

Fracture-specific parameters and general perioperative data were also documented. Using the Constant-Murley score, a prospective clinical evaluation was performed after surgery. 4 A goniometer was used to evaluate the functional range of motion. A force gauge made by isobex was used for the tests. Clinical evaluation of axillary nerve anterior branch impairment.  

Device implantation and surgical method

A beach-chair posture was adopted for the patient. The MIPO method requires the fracture to be displaced valgus. A varus-displaced fracture should ideally be put into a valgus position by closed motions under fluoroscopic supervision. Care must be used throughout this treatment to prevent causing another dislocation. Another option is to use a K-wire implanted in the humerus head as a joystick. A radiolucent targeting device for the Philos1 system was employed, or a percutaneous osteosynthesis approach. The osteoporotic bone and the humeral head and shaft were fixed with angle-stable screws using a five-hole Philos1 Plate. After sliding the plate along the humeral shaft, it was tucked away beneath the delta muscle. Either by hand or using a Langenbeck retractor, the axillary nerve always was hidden from view. After the first proximal and distal fixation, a cortical screw was inserted into the bone's shaft to hold it to the plate. It is possible that a final plate repair of the humeral head was required, although this would have depended on the quality of a bone and the specifics of the fracture. The patient was immediately put into active aided mobility without the need of a sling.

Fig. 1: A snowboarding accident left a 24-year-old patient with a fracture of the proximal humerus.

Statistics

The number of observations is expressed as a percentage (%) or a standard deviation (SD). Wilcoxon's test or each analysis of variance (ANOVA) were used to compare groups numerically for the matched functional outcome. The cutoff for significance was a p value of less than 0.05. For the statistical analysis, we utilized PASW Statistics for Windows, version 19.

Surgical procedure

The average age of the group studied was 62.13. Low-energy trauma, such as those sustained in falls when skiing or snowboarding, was the most prevalent cause of the injury. Around half of patients had their dominant arm hurt. Type A fractures accounted for 19%, type B for 47%, and type C for 34%, according to the AO/OTA classification. In the first X-ray, the articular surface was observed to be displaced valgus in 73 cases and varus in 24 cases.

Average trauma patients waited 0.5 days before undergoing surgery. It took the 16 surgeons operate an average of 73.27 minutes in the operating room and 108.121 seconds under fluoroscopy to perform the procedure.

Fig. 2: An AO categorization of the frequency of fractures treated using a non-invasive method.

The Duration of the Follow-Up Process

Eight problems occurred over the 18-month follow-up period. At 7 weeks, secondary screw perforation was the most prevalent consequence (7.2%). There was no hardware breakdown throughout the observational period.

Head-shaft angulation altered considerably between the postoperative assessment and the last follow-up X-ray as varus displacement increased. Eight individuals had avascular necrosis of a humeral head (8.2%).

Shoulder function

At the conclusion of the follow-up period, the average Constant score for the repaired shoulder was 75.11, whereas the score for the undamaged shoulder was 83.7. Even though the fractured humerus improved to the point where its function was 91% as good as the contralateral side, matched analyses showed a substantial functional disparity (p 0.01).

Fig. 3: Comparison of the damaged shoulder's absolute mean Constant score at each follow-up (FU) visit compared to the uninjured contralateral side.

One and only No statistically significant variations in functional result were found between AO/OTA fracture types A, B, and C using analysis of variance. Four people with atrophy of the anterior deltoid border and an axillary nerve injury showed no clinical signs of injury.

Fig. 4. The Constant score after 12 months following treatment for AO/OTA A, B, and C proximal humerus fractures.

Table 1: Patient profiles for proximal humerus fractures treated with ADSPO

Minimally invasive proximal humerus plating had positive functional and radiological effects in our investigation. Our findings employing the delta-pectoral method are consistent with those found in the literature. Both surgical time or avascular necrosis were reduced with the least invasive technique compared to the traditional delta-pectoral method.

With the success of minimally invasive surgery on the tibia and femur, it was only a matter of time before this technique was used to the plating of fractures in the proximal humerus. The PHILOS surgical approach has evolved from a purely percutaneous technique using a proximal aiming block to a much-simplified percutaneous aiming system utilizing a LCP. The proximal humerus fractures that were treated conservatively showed good outcomes in the medical literature.⁵ Our findings are consistent with those of Hanson et al., who conducted a prospective 1-year examination of 124 patients and reported a difference in Constant scores of 8 between the damaged and uninjured shoulders. While the studies should be similar, it is conceivable that they are not since only 4.7% of the non-displaced injuries treated conservatively and 1.2% of the 4 fractures were displaced.⁶ There was no significant difference in Constant scores after 2 years between the non-operated and operated-on groups, however we do consider a score of 61 to be rather low.⁷ Nonetheless, a beta error is possible given the small sample size, and the preference for plate fixation remained. A randomized controlled trial was conducted to evaluate the effectiveness of plate fixation against conservative treatment. One year following surgery, the affected arm's Constant score was much lower than it had been at the study's beginning.⁸

Moreover puzzling is the lack of a price distinction between operational and nonoperative treatment. Researchers found that after one year, participants using a delta-pectoral technique had a mean Constant score of 72. In a small reported cohort, those who had minimally invasive treatment saw a  point increase in their Constant scores after one year.   Our larger data set yields the same results.⁹

There was a noticeable time gap between surgeries. In contrast to our reported 73 minutes, studies adopting the delta-pectoral technique needed a mean operation duration of 87 minutes and 97 minutes. ¹⁰

The majority of revision procedures after plate osteosynthesis are performed to repair holes made by the screws. Inaccurate intraoperative length measures have been linked to reported incidences of primary screw perforation of 14%. Subsidence of the humeral head seems to be the source of 8%-11% of secondary screw perforations, making prevention challenging. While performing the MIPO procedure, a five-hole plate is recommended to protect the axillary nerve. A larger degree of elasticity may be possible with the longer plate, and screw cut-out may be avoided. Further research should address this issue, since our 7.2% secondary screw perforation rate using the five-hole plate and MIPO approach seems to confirm this theory. ¹¹

Avascular necrosis is reported in up to 34% of cases in historical literature that describes substantial soft-tissue stripping during osteosynthesis. Avascular necrosis occurs in 10-16% of patients according to recent articles that use the traditional delta-pectoral technique while minimizing soft tissue injury. Even more necrosis reduction may be possible with a minimally invasive antero-lateral delta-split technique. Rates between 5% to 8% have been attained. 1 Our 8.2% AVN incidence may also lend credence to using a non-surgical strategy to reducing humeral head ischaemia.¹²

We were able to show that a wide variety of surgeons, all using the antero-lateral MIPO as the conventional method in our clinic, had successfully operated on a sizable number of patients. We'd like to think our findings are generalizable to hospitals where minimally invasive procedures aren't routinely used. Yet, we had a significant challenge in that a large percentage of our patients were non-locals who were unable to return to our facility for follow-up care. This is an issue with our facility since it is located in a recreational area.¹³

Proximal humerus fractures present as a spectrum of injuries with varying degrees of complexity. The pattern of the fracture, the patient's age, the quality of the bone encountered, various patient's objectives, and the surgeon's knowledge with the procedures all play a role in deciding which therapeutic modality will be chosen.The antero-lateral delta-split method for plate osteosynthesis of a proximal humerus produces comparable functional and radiological outcomes to the more conventional delta-pectoral approach. This non-invasive method outperforms the conventional one in certain respects, but only marginally. The technical requirements for the antero-lateral delta-split method are lower, and the time required for surgery is less.

References

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