Fractures of the Humeral Shaft

The Problem

Humeral shaft fractures are common injuries representing 3-5% of all fractures and occur at an incidence of approximately 15 per 100,000 per year. Typically occurring in the elderly patient population, the majority of humeral shaft fractures are the result of a fall and involve the middle third of the shaft (midshaft). Younger patients may sustain this injury following high-energy trauma or due to a penetrating mechanism.

Clinical Presentation

The mechanism of injury is typically blunt trauma. Direct trauma such as a direct blunt force to the arm tends to result in a transverse or comminuted fracture pattern while an indirect force such as a fall on an outstretched hand tends to result in a more spiral or oblique fracture pattern.

Patients will present with an obvious deformity, pain and limited use of the affected upper extremity. Typically there is swelling and shortening of the affected arm. A careful physical exam focused on the neurovascular status is paramount. Specifically, a close assessment of the status of the radial nerve (motor and sensory) is warranted, as it is the most frequently injured nerve (musculocutaneous nerve is the second most commonly injured nerve). Although compartment syndrome of the arm is rare, close attention must be paid to this possible entity especially in segmental fractures and associated forearm fractures (multifocal extremity injury). Obviously an evaluation of the soft tissue envelope for possible open fractures is required to guide management.

Diagnostic Workup

The initial patient evaluation includes a thorough history and complete physical examination. The physical examination should include an inspection to look for deformity, ecchymosis, swelling and any evidence of an open injury. Patients will typically be very tender to palpation at the fracture site. Gross motion at the fracture site is typical, with rotational motion at the fracture site and crepitus present. A thorough neurovascular examination should be performed with particular attention paid to the radial nerve.

Radiographic evaluation:

Orthogonal AP and lateral radiographs of the humerus are required. It is important that a transthoracic lateral view is obtained as manipulation of the extremity will result in isolated rotation of the distal fragment. Traction views may be obtained in severely comminuted fractures to better delineate fracture pattern. X-rays of the elbow and shoulder may also be obtained if the fracture appears to extend towards the metaphysis.

Humeral shaft fractures are often classified by their anatomic location (proximal, middle or distal third) and descriptive (oblique, spiral, transverse, comminuted, etc).

A CT scan or MRI may be considered in the setting of a pathologic fracture, however, there is no indication for advanced imaging modalities for a standard non pathologic fracture.

There is no indication for acute EMG for patients who present with a radial nerve deficit. An EMG is typically obtained approximately 6 weeks after injury if there is no improvement in the neurological status of the patient.

Non-perative Management

Non-operative management is the mainstay of treatment (>90%) with a union rate of greater than 97.5%. The acceptable reduction parameters which allow for acceptable functional and cosmetic results are 20 degrees of sagittal plane angulation, 30 degrees of coronal plane angulation and up to 3cm of shortening or bayonet opposition. Varus angulation of up to 10 degrees is common due to the deforming forces that are present.

Non-operative treatment requires close patient follow up and supervision especially during the early phases of fracture healing. A cooperative patient with an intact and innervated arm musculature and a patient who is not limited to supine positioning are ideal.

The acute non-operative management of the fracture consists of a coaptation splint which is typically applied upon presentation and is maintained for a period of 1-2 weeks to allow for swelling and soft tissue recovery. Medially, the u-shaped splint should be placed as far into the axilla as possible and the splint should extend past the deltoid and onto the neck at its lateral aspect. A valgus mold at the fracture site will help maintain alignment and avoid the common varus deformity that occurs. Fracture blisters are not uncommon in thinner patients and these typically resolve within the first 2 weeks and allow for application of a functional fracture brace.

The post-acute treatment (5-7 days after the injury) typically consists of functional fracture brace which utilizes the hydrostatic pressure generated by the contracting musculature of the arm to internally splint the humerus. It is therefore important that the muscles are functional and that the elbow motion is maintained in order to allow for the required muscle contraction against the constant pressure of the brace to generate the hydrostatic forces. The fracture brace consists of medial and lateral plastic shells which are held together snugly via velcro straps. The patient is relied on to appropriately adjust the straps so that the brace remains snug as the swelling of the acute trauma subsides and atrophy of the musculature evolves. Contraindications to functional bracing may include a tissue injury which requires continual attention, a non-compliant or unreliable patient and inability to maintain acceptable alignment parameters. An open fracture is not an absolute contraindication, however, it is the author’s protocol to internally fix all open humerus fractures following an extensive debridement. Debridement of an open fracture may devitalize the periosteum and therefore may be better suited to surgical stabilization.

Another non-operative treatment option is a hanging arm cast which is likely best utilized in distal third humeral shaft fractures. A hanging arm cast requires that the patient avoid the supine position until fracture healing is obtained since gravity is required for this treatment to be effective. A hanging arm cast is not recommended for transverse or short oblique fractures where there is a limited surface area for bone healing and distraction at the fracture site may lead to nonunion.

Other non-operative treatment options include thoracoacromial bracing and shoulder spica casting. Both of these methods are considered anachronistic and are no longer employed in modern practice.

Functional bracing applied for a period of 8-12 weeks and can be safely discontinued once fracture callous is noted on serial radiographs.

Indications for Surgery

Indications for Surgery:

Open Fracture

Vascular injury requiring repair

Intra-articular fracture

Floating elbow

Polytrauma

Failure of closed management

Surgical Technique

Approaches to the Humeral Shaft

The anterolateral approach is the preferred approach for proximal shaft and midshaft fractures. Proximally the approach can be extended in to the deltopectoral approach and is thus useful for fractures that extend toward the proximal humerus. Distally the approach is extended to the metaphyseal flare of the humerus, however, it is not useful for distal third fractures as these often require fixation into the distal humerus. The radial nerve is identified distally in the interval between the brachioradialis and the brachialis and is dissected proximally and protected as it passes posteriorly through the intermuscular septum to the posterior compartment of the arm. The brachialis muscle is then split to allow direct access to the bone. Distally the antebrachial cutaneous nerve exits between the biceps and brachialis and must be protected.

The anterior approach is preferred for midshaft fractures and is less extensile than the anterolateral or posterior approaches. It utilizes the muscular interval between the biceps and brachialis muscles.

The direct lateral approach is best suited for midshaft fractures as it is less extensile proximally and distally. This approach utilizes the interval between the triceps and the anterior arm musculature and allows for exposure of the radial nerve as it passes from posteriorly to anteriorly across the intermuscular septum.

The posterior approach can be performed as either a triceps splitting or a triceps sparing approach. The authors preferred technique is the triceps sparing approach for a number of reasons. By staying out of the muscle distally, relatively bloodless planes are exposed. Avoiding injury to the triceps muscle may limit intramuscular adhesions and scar formation as well as less risk of denervating a portion of the triceps. Extending the exposure proximally and distally can be accomplished more easily than through the triceps splitting approach, particularly on the lateral side, by mobilizing the radial nerve and elevating the triceps off the humerus. After identifying the tissue plane between the lateral head of the triceps and the lateral intermuscular septum, one can trace the posterior antebrachial cutaneous nerve proximally to identify the radial nerve. Having found this key anatomical structure approximately 14 cm proximal to the lateral epicondyle, the remainder of the triceps can be elevated safely off the humeral shaft. Proximally, the approach is extended by staying between the posterior deltoid and the lateral head of the triceps. The axillary nerve is the limiting factor proximally, however, it can be dissected and protected and a plate can be passed to obtain fixation into the humeral head. This extensile approach allows for visualization of approximately 94% of the humeral shaft.

Patient Set Up

For the anterior based approaches the patient is in a supine position. It is the author’s preference to utilize a radiolucent table with a radiolucent arm board tucked close to the table effectively extending the table laterally to allow for increased workspace. A large C arm can be brought in from the opposite side across the body which keeps it out of the way of the surgeon. Alternatively, the C arm can be brought in from the ipsilateral side. The entire extremity is draped free.

For the posterior approach we prefer a lateral decubitus patient positioning. The extremity is draped free and well-padded elbow positioner is secured to the operating table. Alternatively, a sterile padded mayo stand can be utilized. Although it is possible to position the patient prone for the posterior approach it is our preference to avoid prolonged prone positioning when possible and therefore the lateral decubitus positioning is favored.

Surgical Technique

Open reduction and plate fixation

Open reduction and plate fixation (ORIF) with plate fixation has been associated with the best functional results and is our fixation method of choice for the vast majority of humeral shaft fractures. It allows direct fracture reduction and stable fixation of the humeral shaft without violation of the rotator cuff as would be required with an intramedullary nail. For most adults a 4.5-mm dynamic compression plate (large fragment) is typically used with fixation of 6-8 cortices proximal and distal to the fracture. Primary bonehealing is the goal in most cases and therefore compression plating and lag screws are ideal.

In comminuted fractures a bridge plating technique may be appropriate, however, this requires that meticulous dissection be performed and that the periosteum remains attached to the bridged fragments. Locked plates may be appropriate in bridge plate constructs or in osteoporotic bone but they are not routinely required. In fractures with metaphyseal extension to the distal humerus or to the proximal humerus specialized plated and extensile approaches (as detailed above) may be required. The status of radial nerve must be checked throughout the procedure and careful attention should be given to avoiding injury to the nerve with hardware placement. Submuscular plating techniques for the humeral shaft have been described but these are complicated techniques and are not recommended as a routine treatment option.

Intramedullary fixation

Intramedullary fixation remains an attractive option for humeral shaft fractures. However, injury to the rotator cuff insertion and subsequent shoulder pathology have made this technique less popular. Additionally, studies indicate higher union rates with plating of the humeral shaft. Intramedullary nailing is often considered in long segmental fractures where plate placement would require significant soft tissue dissection and possibly a submuscular plating technique. Pathologic fractures as well as fractures in extremely osteoporotic bone have also been classically treated with intramedullary fixation. When utilizing intramedullary nailing the proximal locking bolts may pose an injury risk to the axillary nerve. Many surgeons prefer to make a small anterolateral approach to visualize and protect the radial nerve as the nail is passed across the fracture in order to avoid potentially injuring the radial nerve during nail passage. Distally lateral to medial locking risks injury to the lateral antebrachial cutaneous nerve as well as the radial nerve. Anterior to posterior locking can be performed under an open approach to avoid a vascular injury.

External fixation

External fixation of humeral shaft fractures is reserved for multiply injured ICU patients, open fractures with significant soft tissue loss, burn patients, infected fractures, etc. Thorough knowledge of the cross sectional anatomy of the humerus is critical for safe external fixation placement. Pin placement in the middle third of the humeral shaft should be avoided due to the lack of a distinct safe zone in this area.

Pearls and Pitfalls of Technique

• Understand the advantages and disadvantages of each of the surgical approach to the humeral shaft — allowing for the use of the appropriate approach for each fracture type.

• Need to identify the radial nerve intra-operatively when utilizing the anterolateral or posterior approaches to the humerus.

• Fracture gaps are poorly tolerated in the humeral shaft and should be avoided during ORIF – need compression with rigid stabilization when possible.

• Locking plates may be beneficial when managing humeral shaft fractures in elderly patients with osteoporotic bone and for small, proximal or distal fracture fragments.

Potential Complications

• Radial Nerve Palsy — systematic review of more than 4,000 humeral shaft fractures reported a radial nerve palsy in 11% of fractures with a higher incidence in distal 1/3 fractures, transverse and spiral fractures. The current recommendation is observation with extension splinting of the wrist and fingers when present. If no early return of function is present, an EMG can be obtained as early as 6 weeks after injury, often showing fibrillation potentials, positive sharp waves and monophasic action potentials when a radial nerve injury is present.

• Nonunion — relatively rare complication and when present the etiology needs to be figured out to help direct treatment. Hypertrophic nonunions require improved fracture site stability. Atrophic nonunions need stimulation of fracture healing biology (bone grafting, etc). Infected nonunions need to be identified and treated accordingly.

Post-operative Rehabilitation

Humeral shaft fractures typically take 3-4 months to heal.

Post-operatively patients are placed into a fracture brace and use a sling for comfort. Our post-operative rehabilitation protocol includes immediate active and active-assisted shoulder and wrist range of motion under the guidance of the physical therapist. Elbow range of motion (AROM, AAROM) starts at 2 weeks post-op. Patients are kept non-weightbearing on the affected upper extremity for 6 weeks. At 6 weeks, progressive strengthening is encouraged with a return to usual activities once there is evidence of healing on post-operative radiographs, the fracture site is no longer tender to palpation and the patient has regained full range of motion and strength.

Outcomes/Evidence in the Literature

Carroll, EA, Schweppe, M, Langfitt, M, Miller, AN, Halvorson, JJ. “Management of Humeral Shaft Fractures”. JAAOS. vol. 20. 2012. pp. 423-433. (Review article outlining the evaluation and management of humeral shaft fractures.)

Walker, M, Palumbo, B, Badman, B, Brooks, J, Van Gelderen, J, Migehll, M. “Humeral Shaft Fractures: A Review”. JSES. vol. 20. 2011. pp. 833-844. (Review article outlining the evaluation and management of humeral shaft fractures.)

Zlotolow, DA, Catalano, LW, Barron, OA, Glickel, SZ. “Surgical Exposures of the Humerus”. JAAOS. vol. 14. 2006. pp. 754-765. (Review article outlining the various surgical approaches for exposing the humerus.)

Sarmiento, A, Zagorski, JB, Zych, GA, Latta, LL, Capps, CA. “Functional Bracing for the Treatment of Fractures of the Humeral Diaphysis”. JBJS. vol. 82. 2000. pp. 478-486. (Functional bracing for the treatment of fractures of the humeral diaphysis is associated with a high rate of union, particularly when used for closed fractures. The residual angular deformities are usually functionally and aesthetically acceptable.)

Denard, A, Richards, JE, Obremskey, WT, Tucker, MC, Floyd, M, Herzog, GA. “Outcome of Nonoperative vs Operative Treatment of Humeral Shaft Fractures: A Retrospective Study of 213 Patients”. Orthopedics. vol. 33. 2010. (Two-hundred thirteen adult patients with a humeral shaft fracture who satisfied inclusion criteria were treated at 2 level 1 trauma centers with either a functional brace (non-operative treatment group) or compression plating (operative treatment group). The occurrence of nonunion (20.6% vs 8.7%; P=.0128) and malunion (12.7% vs 1.3%; P=.0011) was statistically significant and more common in the non-operative group. No difference in time to union or ultimate ROM was found between the 2 groups.)

Jawa, A, McCarty, P, Doornberg, J, Harris, M, Ring, D. “Extra-Articular Distal-Third Diaphyseal Fractures of the Humerus: A Comparison of Functional Bracing and Plate Fixation”. JBJS. vol. 88. 2006. pp. 2343-2347. (Nineteen patients managed with plate-and-screw fixation and twenty-one managed with functional bracing. For extra-articular distal-third diaphyseal humeral fractures, operative treatment achieves more predictable alignment and potentially quicker return of function but risks iatrogenic nerve injury and infection and the need for reoperation. Functional bracing can be associated with skin problems and varying degrees of angular deformity, but function and range of motion are usually excellent.)

Kobayashi, M, Watanabe, Y, Matsushita, T. “Early Full Range of Shoulder and Elbow Motion Possible After Minimally Invasive Plate Osteosynthesis for Humeral Shaft Fractures”. J Orthop Trauma. vol. 24. 2010. pp. 212-216. (Minimally Invasive Plate Osteosynthesis is a promising option for humeral shaft fractures because of the early recovery of motion in adjacent joints. Elbow function requires longer recovery time than the shoulder, and this may be due to the distal approach.)

Heineman, DJ, Pollman, RW, Nork, SE, Ponsen, KJ, Bhandari, M. “Plate Fixation or Intramedullary Fixation of Humeral Shaft Fractures”. Acta Orthop. vol. 81. 2010. pp. 216-223. (Meta-analysis pooling the data of 4 trials (n = 203 patients) did not find a statistically significant difference between implants in the rate of total complications, non-union, infection, nerve-palsy, or the need for reoperation.)

Bishop, J, Ring, D. “Management of Radial Nerve Palsy Associated with Humeral Shaft Fracture: A Decision Analysis Model”. J Hand Surg Am. vol. 34. 2009. pp. 991-996. (Decision analysis model showed that initial observation was the preferred strategy. In clinical settings in which the likelihood of spontaneous recovery of nerve function is low or when an informed patient has a strong preference for surgery, early surgery may optimize outcome.)

Sonneveld, GJ, Patka, P, van Mourik, JC, Broere, G. “Treatment of Fractures of the Shaft of the Humerus Accompanied by Paralysis of the Radial Nerve”. Injury. vol. 18. 1987. pp. 404-406. (Reports the results of treatment of 17 patients with fractures of the shaft of the humerus accompanied by paralysis of the radial nerve in a series of 111 patients with fractures of the shaft of the humerus. The high incidence of undamaged nerves at exploration suggests that a conservative approach by collar and cuff or Sarmiento bracing is justified in such cases of fractures of the shaft of the humerus. Paralysis of the radial nerve associated with fractures of the shaft of the humerus is, in our opinion, not an indication for early operative treatment.)

Summary

Humeral shaft fractures are relatively common injuries occurring in elderly patients due to blunt impact mechanisms. The vast majority of humeral shaft fractures can be successfully managed non-operatively with temporary splinting followed by fracture bracing and rehabilitation. For selected indications operative treatment with plate and screw fixation or intramedullary fixation may be undertaken. A thorough knowledge of the various surgical approaches to the humerus with careful attention to the radial nerve can lead to successful fracture healing with a reliable return to function.

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