Disclosures: Carroll reports he receives royalties from Globus, is a consultant for DePuy Synthes and Globus, and is a speaker for DePuy Synthes, AO North America and AO Foundation.AO North America. Marenghi and Scholten report no relevant financial disclosures.
September 22, 2021
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Young woman with right arm pain after being struck by a vehicle at a racetrack

Disclosures: Carroll reports he receives royalties from Globus, is a consultant for DePuy Synthes and Globus, and is a speaker for DePuy Synthes, AO North America and AO Foundation.AO North America. Marenghi and Scholten report no relevant financial disclosures.
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A 22-year-old right-hand dominant woman presented to the ED with right arm and forearm pain after being struck by a car when she was on the sideline at an auto race. The car went off track, crashing into a barrier behind which she was standing.

Examination of the patient revealed a gross deformity of the right upper arm with a 5-cm laceration about the anterior lateral aspect of the distal humerus and a gross deformity of the right forearm with a punctate wound on the radial aspect of the proximal volar forearm. The right upper extremity was neurovascularly intact. Examination of her other extremities revealed no open wounds or gross deformities. She had intact sensation and motor function.

Radiographs of the right forearm revealed a segmental right radial shaft fracture that consisted of a distal-third short oblique fracture of the radial diaphysis, comminuted fracture of the proximal-third radial diaphysis and a radial neck fracture, as well as a comminuted fracture of the proximal-third ulnar diaphysis. Radiographs of the right humerus revealed a comminuted intra-articular supracondylar humerus fracture and a fragmented wedge fracture of the middle third of the humeral diaphysis with obvious subcutaneous gas present (Figure 1).

Initial management involved administration of cefazolin and tetanus vaccination confirmation, irrigation and debridement (I&D) of open right-arm wounds. Longitudinal traction was applied prior to dressing the wounds and placing a well-padded posterior long arm splint. CT scan of the right elbow was obtained to characterize the intra-articular distal humerus fracture. The patient underwent irrigation and debridement, with wound closure and splinting with definitive fixation to be done by a traumatologist.

Operative details

The patient was placed into a left, lateral decubitus position. The right upper extremity was draped over a radiolucent arm board and prepped and draped in a sterile fashion.

For fracture fixation, we worked from proximal to distal, starting with the humeral shaft. A Gerwin approach was made to the posterior humerus. A Penrose drain was placed around the radial nerve, which was protected throughout the procedure. Given the fracture comminution, we utilized a bridge plating technique with a 3.5-mm Locking Compression Plate (Synthes) to restore length, alignment and rotation. The radial nerve was inspected and found to course across the midportion of the posterior plate in a tension-free fashion.

Given the intra-articular extent of the distal humerus fracture, we chose to utilize an olecranon osteotomy to best visualize the articular surface for anatomic reduction. The incision was extended distally along the ulna just distal to the level of the ulna shaft fracture. We isolated the ulnar nerve throughout the zone of injury and the zone of planned instrumentation. A Penrose drain was placed around the nerve to facilitate its identification throughout the remainder the procedure. Our plan was to bridge the ulnar shaft fracture and neutralize the olecranon osteotomy site with an olecranon plate. In planning for the length of the plate, we needed to get the ulnar shaft fracture stable and out to length, which was achieved with an adjunctive mini-fragment reductive plate. The appropriate length olecranon plate was chosen and multiple screw holes were pre-drilled through the plate. Doing this prior to the olecranon osteotomy facilitated an anatomic reconstruction of the osteotomy. The plate was then removed. We performed a Chevron olecranon osteotomy using an oscillating saw and osteotome (Figure 2).

The extensor mechanism was retracted from distal to proximal, which allowed for visualization of the articular surface. We used an adjunctive reductive plate for the metadiaphyseal aspect of the medial column, converting an AO type C fracture to a type B. Working in a counterclockwise fashion, we then reduced the articular surface and neutralized this with a direct medial plate and then neutralized the lateral column with a posterolateral plate. A long medial plate was chosen to overlap the humeral shaft fracture and its plate construct to avoid any stress risers and subsequent risk of peri-implant fracture. The ulnar nerve was inspected and noted to be free and to not subluxate with flexion of the elbow.

We decided to remain in a lateral position for fixation of the radial head fracture. Reflecting the olecranon osteotomy and extensor mechanism allowed for good visualization of the radiocapitellar joint. We used a Kaplan approach to achieve an anatomic reduction of the radial head fracture, which was neutralized with a 1.5-mm T plate. The olecranon osteotomy was repaired using the previously identified plate and pre-drilled holes (Figure 3).

The wound was irrigated and closed in a layered fashion. The patient was repositioned into a supine position and the right arm was again prepped and draped. We continued to work proximal to distal for fixation of the segmental radial shaft fracture. The incision from the initial debridement and irrigation was used for a volar Henry approach. The proximal and distal radial shaft fractures were reduced anatomically under direct visualization and neutralized with 2.7-mm plates. We focused on implant choice so that we had adequate overlap between plates to minimize the risk of stress risers and subsequent peri-implant fracture.

Final radiographs demonstrated no complicating features. The postoperative plan included range of motion as tolerated to the right elbow, wrist and fingers with no weight-bearing throughout the right upper extremity (Figure 4).

Radiographs at 4 months postoperatively revealed healed fractures with no hardware complications (Figure 5).

Discussion

A floating elbow is a rare high-energy injury with little published literature, particularly in the adult population. The reported incidence ranges from 2% to 13%. The term was initially described by Lyle J. Micheli, MD, and Carl L. Stanitski, MD, in 1980 and applied to children with ipsilateral humerus and forearm fractures. In 1984, J.F. Rogers and colleagues applied the term to the adult population who sustained these injuries. Variants of the classical definition have been described in case reports and case series and may include intra-articular distal humerus fractures or associated elbow fracture dislocations. Our case was unique in that our patient sustained open segmental fractures of both the humerus and radial shaft.

Given that these are high-energy injuries, a damage control approach may be necessary for initial treatment depending on stability of the patient and their other traumatic injuries. Consideration for external fixation can be given in these scenarios, which has been described in a few case reports. Our patient’s injury was isolated to the right upper extremity and a one-stage approach for definitive fixation could be performed.

Complications of floating elbow injuries include stiffness, nerve palsies and radioulnar synostosis. Verónica Jiménez-Díaz and colleagues performed an analysis of 23 patients treated for a floating elbow injury between 2004 and 2013. They found factors associated with significantly worse range of motion included nerve palsies, radioulnar synostosis and intra-articular distal humerus fractures. Patients with nerve palsies had significantly worse flexion, extension and pronosupination. Patients with radioulnar synostosis had a significant decrease in pronation and supination. Patients with intra-articular distal humerus fractures had significant limitation in elbow extension. However, there was no statistically significant difference in outcome associated with open fractures, order of fracture fixation or techniques used for osteosynthesis.

Olecranon osteotomy provides the most visualization of the articular surface. A prospective cohort study by R. Singh and colleagues compared the paratricipital approach with an olecranon osteotomy for AO 13-C1, -C2 and -C3 fractures. They found similar outcomes with a paratricipital approach and olecranon osteotomy in C1 and C2 fractures. For C3 fractures, they found a paratricipital approach had worse outcomes compared with an olecranon osteotomy. Olecranon osteotomies have potential postoperative complications, including nonunion and hardware irritation. Nonunion of the osteotomy site has a reported rate between 3.3% and 13.3%. Implant choice for olecranon osteotomy can lead to need for hardware removal and may be up to 86% for tension band wiring and up to 30% for plating.

Floating elbows are rare and difficult injury patterns particularly in this case with open segmental fractures of the humerus and forearm. The important take-away points from this case include early administration of antibiotics in the setting of an open fracture, initial irrigation and debridement of the open fractures, achievement of anatomic reduction of intra-articular fractures and providing rigid fixation of fractures to allow early range of motion.