Upper extremity injuries are more prevalent in obese people than in nonobese people after low-energy falls. Because splinting and casting are inefficient methods of stabilization in the setting of obesity, internal fixation provides stability for mobilization and realignment. Morbid obesity adversely affects positioning, surgical exposures, and complications associated with operative fixation. Avoiding short cuts and complications, morbidly obese patients should be able to return to normal functioning.
Health care costs are rising and represent 17.9% of the United States Gross Domestic Product in 2009. Representing almost 10% of all medical spending in 2008, obesity is a major component of health care costs. In the United States, obesity prevalence continues to increase over the past 40 years and is associated with decreased national productivity, medical expenditures, comorbidities, and perioperative complications. Obese individuals have up to 48% greater risk of injury, incurring higher rates of trauma, and lower extremity fractures in general. Specifically, obese people have an almost 2-fold increased chance of upper extremity injury as compared with those who are nonobese. Obese patients have a higher risk of sustaining a displaced elbow fracture than normal-weight patients.
This article discusses the treatment options and recommendations of upper extremity injuries in the setting of morbid obesity.
Shoulder injuries
Shoulder injuries can be subgrouped into clavicular, scapular, and proximal humeral fractures. The treatment of clavicular and scapular injuries in obese patients is similar to that in nonobese patients.
Problems arise with the combination of morbid obesity and unstable displaced proximal humeral fractures. Operative treatment options for displaced proximal humeral fractures are controversial. When combined with morbid obesity, fixation options can be problematic. A potential fixation option is closed reduction/percutaneous fixation. The 2.5-mm terminally threaded Schanz pins (Synthes, Paoli, PA, USA or Zimmer, Warsaw, IN, USA) are available in 250 or 300 mm length. However, swelling associated with fracture hematoma and obesity creates arm girth wider than commercially available pin length, restricting use of this procedure until swelling abates or abandoning the procedure.
Open reduction internal fixation via a deltopectoral interval or an extended lateral deltoid-splitting approach requires a large extensile incision. Because the proximal humeral plate is applied lateral to the biceps groove, the standard deltopectoral approach can limit unobstructed plate application secondary to the muscular interval being anterior to the plate location and to the depth of the dissection. The newly modified extended anterolateral acromial approach is probably the best suited for unobstructed plate application. In morbidly obese patients, the short drill sleeve and bit lengths can encumber minimally invasive plate application via submuscular plating.
Another option for salvage of displaced unstable proximal humeral fractures is arthroplasty. The problem with the deltopectoral approach and insertion of a proximal humeral arthroplasty stem is arm adduction and extension. Obesity, pendulous breasts, and wide girth all deter in line insertion of the arthroplasty stem within the humeral diaphysis. Having the patient placed onto the lateral aspect of the table with slight reverse Trendelenburg positioning can facilitate extension and adduction arm positioning. The surgeon must be prepared for all treatment methods concerning proximal humeral fixation.
Author’s Preferred Method
Since utilization of the upper extremity for weight bearing or getting out of a chair is common with morbid obesity, the author prefers locking plate fixation of proximal humeral fractures to insure stable fixation, avoid pin tract infections, and enhance mobilization. For unstable, dysvascular, and nonreconstructable fractures requiring arthroplasty, the author prefers a radiolucent table in reverse with the patient in a 30° reverse Trendelenburg and in a far ipsilateral lateralized position for positioning.
Humeral diaphyseal injuries
Most of the humeral fractures can be successfully treated with closed techniques. A typical treatment algorithm is initiated with humeral realignment and reduction maintained with a coaptation splint extending from under the axilla to above the shoulder. Once swelling and pain subside, the coaptation splint is changed to a fracture or functional brace. Functional bracing relies on hydrostatic forces to maintain fracture alignment and length. Bracing is maintained until stable callus formation develops and pain diminishes. Range of motion in and out of the brace is initiated based on fracture healing and stability.
Attempts at successful closed treatment of humeral diaphyseal fractures in obese patients are fraught with problems and complications. Splinting requires 3-point molding to achieve realignment ( Fig. 1 ). With excessive adiposity, bending moments are minimal, and alignment is unable to be achieved. Furthermore, in obese women more than in men, chest wall and breast size create a varus bending moment that is unable to be counteracted with traditional closed methods. Applying a rolled towel or bump on the medial aspect of the elbow outside of the splint will potentially offset the chest wall and breast forces. Once the initial pain and swelling subside, functional bracing begins. Functional bracing requires daily utilization that increases sweating, skin breakdown, and hygiene problems. Also, with the adiposity, hydrostatic forces are diminished if not absent. Therefore, closed methods of treating humeral diaphyseal fractures are insufficient.
Open treatment options in humeral diaphyseal fracture treatment are external fixation, plating, and nailing. External fixation is usually limited to temporary fixation or to situations with problematic soft tissues precluding open treatment. Furthermore, neural and vascular structures limit the safe corridors for external fixation pin insertion. Because pin longevity is dependent on skin and muscle motion, adiposity increases the bone to bar distance and pin-tract irritation.
Plating of humeral fractures in obese patients should be performed in a supine or a lateral position. Prone positioning should be discouraged. Anterior approaches to the humerus should be performed for proximal or middle diaphyseal fractures, whereas posterior approaches should be performed for middle or distal diaphyseal fractures. An alternative, albeit less used, is the lateral approach, which facilitates exposure to the entire humerus but requires careful dissection around the radial neurovascular bundle. Because of the forces required for mobilization in obese patients, larger (4.5 mm not 3.5 mm, broad not narrow, and limited contact dynamic compression plates not reconstruction plates) and longer (>8 hole) plates should be applied ( Fig. 2 ). Therefore, longer plates require larger exposures. Obesity and larger exposures require incisions the entire length of the humerus. Shorter incisions and smaller exposures limit reduction and plate application. Also, struggling with plate application in obese settings can increase the risk of neural injury. If performed properly, humeral plating results in predictable healing with excellent alignment.
Nailing of humeral fractures can be performed antegrade in a supine position or retrograde in a lateral position. Antegrade nailing is inserted through a rotator cuff incision. The arm requires adduction to assure appropriate start site positioning and trajectory. The appropriate start site and trajectory is problematic with obesity and sometimes impossible with morbid obesity. Chest wall and breast girth impedes adduction of the arm. Occasionally, extension of the arm allows enough adduction for nail insertion. Without adduction, attempted nail insertion will generate increased hoop stresses with medial wall comminution and/or varus alignment. In some cases, the lateral wall of the proximal segment can be reamed away, generating an unstable situation for nail interlock stability and increasing the risk of nonunion ( Fig. 3 ). Start site entrance and proximal reaming trajectory can be enhanced with proximally inserted joysticks (2.5-mm terminally threaded Schanz pins, Synthes, Paoli, PA, USA) tilting the head into neutral or valgus and out of varus ( Fig. 4 ). Furthermore, placing the patient into a bumped supine or slight lateral position with a rolled bath blanket diverts the panniculus to the contralateral flank, improves fluoroscopic visualization, and aids arm adduction ( Fig. 5 ). Extreme adduction of the proximal segment with a mallet or manually with the surgeon’s palm during reaming will aid anatomic alignment. It is not known if this sustained or intermittent pressure can cause radial nerve injury or not.
Lateral positioning and retrograde nail insertion through the intercondylar notch is also an option.
Author’s Preferred Method
Because morbidly obese patients require upper extremity strength and weight bearing for mobilization from a chair or with an ambulatory assistive device, the author prefers lateral positioning to minimize anesthetic risks; posterior approach to the humerus; and plating for stabilization to provide rigid, absolute stability, and early mobilization.
Humeral diaphyseal injuries
Most of the humeral fractures can be successfully treated with closed techniques. A typical treatment algorithm is initiated with humeral realignment and reduction maintained with a coaptation splint extending from under the axilla to above the shoulder. Once swelling and pain subside, the coaptation splint is changed to a fracture or functional brace. Functional bracing relies on hydrostatic forces to maintain fracture alignment and length. Bracing is maintained until stable callus formation develops and pain diminishes. Range of motion in and out of the brace is initiated based on fracture healing and stability.
Attempts at successful closed treatment of humeral diaphyseal fractures in obese patients are fraught with problems and complications. Splinting requires 3-point molding to achieve realignment ( Fig. 1 ). With excessive adiposity, bending moments are minimal, and alignment is unable to be achieved. Furthermore, in obese women more than in men, chest wall and breast size create a varus bending moment that is unable to be counteracted with traditional closed methods. Applying a rolled towel or bump on the medial aspect of the elbow outside of the splint will potentially offset the chest wall and breast forces. Once the initial pain and swelling subside, functional bracing begins. Functional bracing requires daily utilization that increases sweating, skin breakdown, and hygiene problems. Also, with the adiposity, hydrostatic forces are diminished if not absent. Therefore, closed methods of treating humeral diaphyseal fractures are insufficient.
Open treatment options in humeral diaphyseal fracture treatment are external fixation, plating, and nailing. External fixation is usually limited to temporary fixation or to situations with problematic soft tissues precluding open treatment. Furthermore, neural and vascular structures limit the safe corridors for external fixation pin insertion. Because pin longevity is dependent on skin and muscle motion, adiposity increases the bone to bar distance and pin-tract irritation.
Plating of humeral fractures in obese patients should be performed in a supine or a lateral position. Prone positioning should be discouraged. Anterior approaches to the humerus should be performed for proximal or middle diaphyseal fractures, whereas posterior approaches should be performed for middle or distal diaphyseal fractures. An alternative, albeit less used, is the lateral approach, which facilitates exposure to the entire humerus but requires careful dissection around the radial neurovascular bundle. Because of the forces required for mobilization in obese patients, larger (4.5 mm not 3.5 mm, broad not narrow, and limited contact dynamic compression plates not reconstruction plates) and longer (>8 hole) plates should be applied ( Fig. 2 ). Therefore, longer plates require larger exposures. Obesity and larger exposures require incisions the entire length of the humerus. Shorter incisions and smaller exposures limit reduction and plate application. Also, struggling with plate application in obese settings can increase the risk of neural injury. If performed properly, humeral plating results in predictable healing with excellent alignment.
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