Biomechanical comparison of humeral nails with different distal locking mechanisms: Insafelock nails versus conventional locking nails

Intramedullary nailing for humeral shaft fractures: Is distal locking necessary?

INTRODUCTION

Intramedullary (IM) nailing of humeral shaft fractures is a reliable means to achieve bone union while allowing early motion. The hypothesis was that distal locking is unnecessary due to good primary stability of the impacted nail in the distal, truncated cone portion of the medullary canal. The primary objective of this study was to confirm the success of the procedure without distal locking by identifying failure criteria. The secondary objectives were to compare the outcomes of IM nailing with and without distal locking.

MATERIAL AND METHODS

This was a retrospective, single-center, non-randomized study of 128 patients with a humeral shaft fracture between 2012 and 2020 treated surgically with a long IM nail. Proximal locking was done in every case, then the rotational stability of the nail was tested. Stable nails were not locked distally (group A), while unstable nails were locked distally through an anterior approach (group B). All patients were reviewed with at least 12 months' follow-up.

RESULTS

Distal locking was performed in 30 patients (mean age 63, 17-91) while the fracture in 98 patients (mean age 65, 20-93) did not require distal locking. The average time to union was 4 months (2-6). The average operative time in group B was 87min (35-185) with 90s fluoroscopy time (33-158) versus 52min (20-127) with 44 s fluoroscopy time (12-143) in group A (p<0.05). Four patients in group B suffered postoperative radial nerve palsy and two others had another fracture at the level of the distal locking screws. The union rate did not differ between groups (Group A 94.6%, group B 86.2%, p=0.217) nor did the functional recovery - SSV of 79.5 (10-100) in group A versus 76 (40-100) in group B (p=0.271) - or the range of motion (p>0.05). There were no instances of rotational malunion.

DISCUSSION

Except for certain distal third fractures, distal locking is not necessary to achieve bone union when the nail is impacted into the medullary canal. This reduces the operative time, fluoroscopy time and risk of neurological damage.

LEVEL OF EVIDENCE

IV.

Development of an additively-manufactured functionally-graded expandable implant via the application of the adaptive response surface method: feasibility study on intramedullary humerus nail

The paper introduces the concept of the rational design of a deployable humeral intramedullary nail plug based on a honeycomb structure used for the surgical treatment of humeral shaft fractures. The concept serves for to restore the axial alignment of bone fragments and to maintain stability via bone-nail friction and locking screws. The design nail plug was gained by optimisation process the Latin Hypercube Sampling Design algorithm and Multi-Objective Genetic Algorithm. It was shown that we can use statistical shape function combined by 3 D printing for designing of a new rationally designed implants.

Efficacy of Intramedullary Nailing in the Treatment of Comminuted Proximal Humeral Fractures and Its Influence on Shoulder Joint Function Recovery

In this paper, we have aimed to elucidate the therapeutic effect of intramedullary nailing (IMN) in treating comminuted proximal humeral fractures (CPHFs) and its influence on the recovery of shoulder joint function. For this purpose, 60 cases with CPHFs were selected, particularly from January 2020 to October 2021. In these cases, 28 cases were treated with a locking proximal humeral plate (LPHP) and assigned to the control (Con) group and the remaining 32 patients were treated with IMN and included in the research (Res) group. The therapeutic effect, surgical indicators, total complications, visual analogue scale (VAS) score, and postoperative shoulder joint function score were compared between the two arms. We observed that compared with the Con group, the effective rate in the Res group was higher while the operation time, intraoperative blood loss, and fracture healing time were shorter, the overall complication rate and VAS score were lower, and the postoperative shoulder joint function score was higher, all with statistical significance. The above results indicate that IMN is effective and safe in the treatment of CPHFs, which can validly reduce the discomfort of patients and facilitate the recovery of shoulder joint function.

InSafeLOCK® humeral nailing for humeral nonunions: Clinical and radiological results

Objectives

This study aims to evaluate the clinical and functional results of patients treated with InSafeLOCK® humeral nail and iliac crest autograft for humeral nonunion.

Patients and methods

A total of 15 patients (11 males, 4 females; mean age: 52.1±15.3 years; range, 31 to 78 years) who were followed conservatively for humeral fractures and operated with the InSafeLOCK® humeral nail and iliac bone graft in our center between June 2018 and January 2020 were retrospectively analyzed. Data including demographic and clinical characteristics of the patients, operative data, and pre- and postoperative Visual Analog Scale (VAS), Disabilities of the Arm, Shoulder, and Hand (DASH), and Constant-Murley Scores (CMS) were recorded.

Results

The mean time from injury to nonunion treatment was 10.9±1.6 months. Five patients had atrophic, eight patients had oligotrophic, and two patients had hypertrophic nonunion. Preoperatively, the mean DASH was 37.7±9.1, the mean CMS was 69.7±6.3, and the mean VAS was 3.8±0.7. In all patients, union was achieved. The mean operation time was 59.0±16.2 min. The mean postoperative DASH score was 16.1±8.7, CMS 87.4±3.4, and VAS score 0.8±0.7. Regarding the shoulder joint, the mean abduction was 164.7±11.3 degrees, the mean internal rotation was 82.0±6.8 degrees, the mean external rotation was 81.3±8.3 degrees, and the mean flexion was 162.0±12.1 degrees. During follow-up, complications such as vascular-nerve injury, reflex sympathetic dystrophy, screw migration or loosening, implant failure, and loss of reduction did not occur in any of our patients.

Conclusion

Considering the satisfactory functional and radiological results, the InSafeLOCK® humeral nail can be used safely in humeral nonunions.

Can the complications of distal locking be prevented with a new nail that offers a novel locking technique in the treatment of humeral shaft fractures?

OBJECTIVES

This study aims to investigate whether complications related to distal locking can be prevented with InSafeLOCK® nail in the treatment of humeral shaft fractures.

PATIENTS AND METHODS

Hospital records of 31 patients (15 males, 16 females; mean age 54.4±10.1 years; range, 20 to 86 years) treated with InSafeLOCK® nail for humeral shaft fractures were investigated retrospectively between February 2016 and January 2019. Arbeitsgemeinschaft für Osteosynthesefragen (AO) classification was used to determine the type of fracture. During the implementation, the elapsed time for distal locking was investigated. Complications encountered during both implementation and postoperative follow-up were investigated.

RESULTS

Fourteen of the fractures were type A, 12 were type B, and five were type C. The mean follow-up time was 18.2 (range, 6 to 30.5) months. The mean duration for distal locking was 2.1 (range, 1.2 to 3.1) minutes. In one (3.2%) patient, cortical penetration occurred at the anterior cortex of the humerus at distal to the nail. In one patient, nail breakage occurred at the distal part of the nail. In one patient, rotational instability occurred due to screw loosening.

CONCLUSION

InSafeLOCK® humeral nail is safe when applied with the recommended technique. It can easily be applied without damaging the veins, nerves or other soft tissues around the elbow due to the internal distal locking feature; furthermore, there is no need to use fluoroscopy or targeting guide. Thus, it is possible to avoid complications that may occur during and after distal locking in conventional intramedullary nail implementations.