Introduction
Anatomic repair and reconstruction of the distal biceps tendon footprint is the treatment of choice among patients who desire a return to full elbow flexion and supination strength after distal biceps rupture. Although good to excellent results are achieved in the majority of patients after distal biceps repair, the surgical complication rate varies from 16% to 26%. Careful preoperative planning may mitigate some common pitfalls of surgery. Further understanding of unanticipated complications in the intraoperative and postoperative setting are paramount to achieving a successful outcome following repair.
Preoperative Considerations
Early recognition of distal biceps ruptures is paramount to ensuring good outcomes and minimizing complications of surgical repair. Chronic tendon ruptures (>4 weeks) are associated with tendon retraction and fibrosis encountered at the time of repair. As a result, repair of chronic distal biceps rupture has demonstrated higher rates of complications, , including nerve injury, when compared with acute repairs.
After a patient presents with a distal biceps rupture, advanced soft-tissue imaging should be acquired urgently (ideally within 3 weeks). Magnetic resonance imaging (MRI) or ultrasound (US) is essential to determining the extent of tendon retraction and potentially the reparability of the ruptured tendon. MRI also helps to delineate the neurovascular anatomy surrounding the anatomic footprint, which may help navigate around any interfering structures encountered during the surgical approach ( Fig. 36.1 ).
Irreparable Distal Biceps Caused by Excess Tendon Retraction
Excessive tendon retraction is a difficult problem that is usually the result of delayed repair and can usually be avoided by acute management within 3 weeks of injury. Preoperative imaging studies (MRI or USS) can help delineate the degree of retraction. When operating on a patient with significant retraction more than 6 to 8 cm and/or a patient whose injury occurred more than 4 weeks from the time of surgery, we routinely consent our patients for the potential need for an allograft reconstruction/augmentation. If the needs arises in the operating room and the patient has not consented for the use of allograft, or if the patient refuses consent for the use of allograft, another option is tenodesis of the remaining biceps tendon to the brachialis. This technique may improve flexion strength but not supination strength.
Recent studies have shown that good patient satisfaction and range of motion (ROM) can be achieved even if the tendon is repaired in up to 60 degrees of flexion. If one has to flex the arm more than 60 degrees to get the tendon back to the tuberosity, failure to regain full ROM is a potential risk. Postoperatively, the elbow should be immobilized in a posterior plaster splint or in a locked brace in 90 degrees of flexion with neutral pronation-supination for the first 2 weeks, followed by an increase in elbow extension in the brace each week in 10-degree increments.
Intraoperative Complications
Nerve Injury
Lateral antebrachial cutaneous nerve (LABCN) injury is the most common complication after distal biceps repair and occurs after approximately 6% to 13% of distal biceps repairs. , It is the most common complication following both single- and dual-incision repair techniques, but is more frequently reported with the single-incision technique. , LABCN injury manifests as numbness over the lateral aspect of forearm. The injury itself is a relatively minor complication and not clinically meaningful unless symptoms persist for more than 2 months. Although it occurs as a transient neurapraxia in the vast majority of cases, traumatic laceration can occur and may result in a painful neuroma or permanent numbness.
LABCN injury can be prevented by identifying and protecting the nerve during anterior single-incision approach, particularly during release of adhesions in the setting of chronic ruptures. The LABCN can be consistently identified by its parallel course with the cephalic vein within the superficial fat. Following skin incision, identify the cephalic vein and its branches at the level of the elbow joint. In the majority of settings, the LABCN runs parallel and volar to the cephalic vein at this level. About 14% of the time, the LABCN can be found crossing under the cephalic vein at the level of the elbow joint and proceeding dorsal to the vein within the elbow. This can be differentiated from the superficial radial nerve which runs deeper to the LABCN either covered by or closely adherent to the brachioradialis muscle fascia. Once the LABCN is identified superficially, it can be protected and tagged with a vascular loop. Furthermore, using a limited anterior incision and limiting the amount of skin tension during retraction can also minimize injury.
Radial sensory nerve (RSN) injury is a relatively minor complication that occurs in 5% to 10% of repairs. , It manifests as numbness overlying the dorsal-radial hand and thumb. Like LABCN neuropraxia, RSN neuropraxia is considered a relatively minor complication and not clinically meaningful unless symptoms persist for more than 2 months. RSN neuropraxia is typically related to aggressive lateral retraction, therefore care must be taken to minimize the amount of retraction with a tension-free incision, as well as intermittent relaxation during retraction.
Posterior interosseous nerve (PIN) injury is a devastating complication that manifests as weakness out of proportion to postoperative pain along with radial deviation with attempted wrist extension, inability to extend the thumb, and inability to extend the finger metacarpophalangeal joints. PIN injury can occur in 1% to 10% of distal biceps tendon repairs. , PIN injury can occur with both single- and dual-incision approaches, and, although recent retrospective studies have shown no significant difference in the rate of occurrence, historically higher rates were associated with the single-incision technique. The PIN is at risk from entrapment underneath a cortical button, errant drill placement, or transection during exposure of the proximal radius or retractor placement. If using a single-incision anterior exposure, the PIN should be protected by supinating the forearm. Drilling with the arm in full supination and directing the drill from anterior to posterior in a slightly ulnar direction can decrease the risk for injury. , This technique increases the distance of the nerve from the drill bit to approximately 7 to 9 mm. If using a dual-incision technique, the PIN can be protected during the posterior approach by pronation of the forearm to move the PIN anteriorly. With either approach, one should avoid the use of Hohman retractors around the radial aspect of proximal radius because these retractors can compress the nerve underneath. We prefer to use an Army-Navy retractor for radial-side retraction, and to use oscillation mode while drilling to avoid soft tissue entrapment of the nerve. Lastly, if using a cortical button for fixation, one can make a small posterior-lateral incision to directly visualize the button before it is seated to ensure that the nerve is not incarcerated underneath.
Median nerve injury is a very rare yet devastating complication that occurs in 0.1% to 4% of cases. , Injury to the median nerve manifests as weakness with thumb interphalangeal joint flexion and opposition, finger flexion, and wrist flexion, as well as numbness on the volar aspect of the most radial three digits and palm. Injury occurs from dissection medial to the neurovascular bundle or aggressive medial retraction. Careful understanding of the anatomy is paramount before surgical approach. Preoperative MRI is helpful to identify if the nerve is in close proximity along the entire surgical approach.
Neuropraxias, by definition, can be observed for spontaneous recovery. In the setting of a persistent painful LABCN neuroma, neuroma excision or relocation within the brachialis or brachioradialis can be considered. If nerve laceration is witnessed at the time of surgery, then acute end-to-end repair is indicated. If recovery is not demonstrated following PIN or median nerve laceration, then tendon transfers are the treatment of choice for functional recovery.
Vascular Injury
Vascular injury is very rare during distal biceps repair, occurring in only 0.2% of cases. However, when vascular injury is reported, it most commonly occurs as a brachial artery laceration. Intimal injury resulting in brachial artery thrombosis attributed to aggressive medial retraction has also been reported. Knowledge of the complex anatomic relationship of vascular structures surrounding the retracted tendon and during approach to the anatomic footprint is paramount. Careful study of MRI imaging preoperatively to recognize the relationship of the vascular structures must be performed.
In the setting of the brachial artery laceration, emergent revascularization should be performed by a qualified surgeon to prevent limb loss. For arterial injury distal to the brachial artery, revascularization of the radial or ulnar artery is recommended, although observation is an option if the hand is still perfused. Always perform an Allen test preoperatively to determine dominance between the radial and ulnar arteries.
Postoperative Complications
Tendon Rerupture or Failure in Continuity
Repair failure or distal biceps rerupture is the second most common major complication after distal biceps repair in recent literature, occurring in 1.5% to 2.5% of cases. , Tendon rerupture most commonly occurs within 3 weeks postoperatively. It can present as an acute rerupture or as gapping at the repair site which renders the repaired tendon incompetent. One should have a high suspicion for failure in continuity if a patient complains of persistent pain and weakness with resisted supination after surgery. A repeat MRI with the affected arm positioned in a flexed, abducted, and supinated position will demonstrate a gap between the distal tendon and the radial tuberosity footprint if a failure in continuity has occurred. Fixation type does not have a well-defined role in repair failure. The most common fixation types are bone tunnels, suture anchors, interference screws, and cortical buttons, as well as combined fixation techniques. Cortical button fixation carries the highest load to failure of all four constructs, with no difference in load to failure noted between the other three construct types. Unfortunately, the majority of clinical studies are underpowered in terms of reporting failures from this specific complication. One comparative study between cortical buttons and suture anchors reported no failures, but a perception of weakness was noted in 20% of cortical button fixation procedures versus 53% of suture anchor fixation procedures. Another comparative retrospective study of patients who underwent suture fixation through bone tunnels versus cortical button with interference screw reported no repair failures in either group, whereas another study of this combined fixation reported a rerupture rate of 1.2%. The rationale for the combined fixation is that the interference screw decreases the cyclical motion at the tendon-to-bone interface. However, there is no strong evidence to definitively suggest that one repair fixation technique to superior to another in terms of minimizing repair failure.
There is also no strong evidence arguing for prevention of repair failure by selecting a specific fixation technique. Ultimately, the choice of fixation depends with which construct the surgeon is most comfortable. More importantly, the surgeon should ensure patient compliance postoperatively by providing the patient with detailed education about limiting excessive force across the repair. Early gentle mobilization has not been associated with repair failure, but caution should be taken with patients who will not be compliant with limiting force across the repair. Protecting patients for up to 3 weeks following repair has not been associated with increased stiffness. We keep everyone in a splint for approximately 10 days before switching to a hinged elbow brace to protect ROM. Patients wear the hinged elbow brace for 5 to 6 weeks after splint removal so that they are protected for a total of about 6 to 8 weeks from surgery. While in the hinged elbow brace, the patient will focus on regaining ROM with progressive increase in extension of about 15 degrees per week. Most patients should regain full ROM by 6 weeks after surgery.
If the patient elects for revision surgery after failure of initial repair, the patient should be consented for revision repair versus tendon allograft reconstruction. At revision, the distal tendon stump should be debrided back to healthy viable tissue and freed of any residual suture material. The radial tuberosity footprint should be cleared of any fibrous tissue. The mechanism of the failure should be thoroughly examined intraoperatively. Suture failure or cortical button failure can be revised with repeat cortical button fixation at a more distal insertion site. In this setting, be sure to place the button far enough from the previous bone tunnels to avoid creation of a stress riser within the radial cortex. If there is a significant length of nonviable tendon which results in a significant gap, then consideration should be given to allograft reconstruction/augmentation.
Proximal Radioulnar Synostosis and Symptomatic Heterotopic Ossification
Elbow stiffness occurs in approximately 2% to 6% of distal biceps repairs, with higher rates of stiffness and forearm rotation loss associated with dual-incision technique. , Furthermore, there is an approximately 1% risk of proximal radioulnar synostosis (PRS). PRS occurrence is 18 times higher with use of a dual-incision technique. The use of bone tunnels and suture fixation as well as postoperative immobilization for more than 28 days is associated with a higher rate of PRS. Symptomatic heterotopic ossification occurs in approximately 3% to 7% of distal biceps repairs ( Fig. 36.2 ). Like proximal radial synostosis, higher rates of symptomatic heterotopic ossification occur with the dual-incision technique.
