Approach to Complex Upper Extremity Reconstruction

Abstract

The management of complex upper extremity trauma can be overwhelming in its urgency and complexity. Having a systematic approach that maintains a clear set of priorities focused on hand and upper extremity function, operative efficiency, and long-term planning for future operations allows the reconstructive extremity surgeon to effectively treat these complex injuries. This article addressed these overall clinical considerations and details the approach taken at the Buncke Clinic including replantation and revascularization as well as osseous and soft tissue reconstruction.

The hand and upper extremity allow humans to interact with and manipulate our environment. The dexterous function that the hand provides allows us to build, shape, create, and heal. This unique combination of mobile and stable components is, however, by virtue of its vital function, prone to injury. Upper extremity injuries in the United States have been estimated to occur with an incidence of 1,130 injuries per 100,000 persons per year. This translates into a 1 in 88 chance of presenting to the emergency department (ED) with an upper extremity injury in the U.S. within a given year. ¹ While many of these injuries remain relatively minor, a portion represent complex upper extremity trauma involving injury to multiple tissue types and necessitating hand and reconstructive surgical expertise.

Upper extremity reconstruction requires knowledge and technical expertise in osseous fixation, nerve repair, vascular surgery, and soft tissue reconstruction. This unique combination requires planning and foresight with respect to future reconstruction and predicted function, while maintaining flexibility and efficiency to handle acute trauma. This combination of both stable and mobile structures also challenges surgeons, therapists, and patients to balance rehabilitation of mobile components while assuring stability.

An inordinate number of variables enter into the treatment of any one complex upper extremity injury; however, several unifying principles may be applied to help simplify decision making. Reconstructive goals depend on hand dominance and patient-related factors including occupational demands as well as access to and willingness to participate in hand rehabilitation. Preservation of length, restoration of perfusion, and preservation of mobile joints when possible are all unifying goals. Dominant hands should be reconstructed with preservation of power grip in mind and therefore require a strong, stable thumb and two or more ulnar digits. In contrast, the nondominant hand typically subserves the role as an assistant, necessitating preservation of precision pinch. This hand should have a sensate thumb and two or more radial digits for executing tripod pinch. Preservation of elbow and shoulder motion is paramount to being able to position the hand in space. Additionally, no injured part should be maintained at the expense or to the detriment of the remainder of hand function. Ultimately, the reconstructive hand surgeon must make decisions as to what will provide the best potential function given the severity of the injury.

Acute Care for Upper Extremity Trauma

Complex upper extremity trauma frequently involves injury to the fingers, hand, and arm to varying degrees. While a mangled upper extremity may be the most obvious injury, the same significant injury mechanism may potentially result in life-threatening injuries outside of the upper extremity. As such, a complete clinical workup should include a full trauma assessment where appropriate. Standard Advanced Trauma Life Support protocols in this setting should be followed with prioritization of airway, breathing, and circulation. Concomitant head, chest, and abdominal injuries must be addressed and take precedence over the extremity. Standard laboratory studies including complete blood count with platelets and major electrolytes are typically included. If significant bleeding has occurred or additional bleeding is anticipated, a blood type and cross-match should also be obtained.

When obtaining history, elucidating time of injury is critically important, especially when treating devascularizing processes. Bone, skin, and muscle have decreasing tolerances to ischemia in that order. Even under ideal storage and cooling, muscle begins to develop irreversible ischemic changes 4 to 6 hours after onset of ischemia. ² The exact mechanism of trauma should be clarified to better establish an expected zone of injury. Generally speaking, sharp guillotine-type injuries often have the most favorable outcomes as the associated zone of injury is narrow and injured structures are typically sharply cut at the same level. These patterns require minimal debridement and will often have favorably oriented proximal and distal structures for repair. In contrast, ballistic, high-pressure, crush, or avulsion mechanisms tend to have a deceptively broader zone of injury and will often require more extensive debridement of devitalized tissue. Heightened clinical suspicion is recommended in evaluating these patients as there is inevitably more soft tissue loss and potentially wider gaps between structures, which may necessitate tissue transfer, grafts, or delayed repair.

As is true for any surgical patient, comorbid conditions such as advanced age, cardiopulmonary disease, hypercoagulable disorders, diabetes, or smoking can all increase the risk for perioperative complications. These factors, while not absolute contraindications to salvage, may alter the available treatment options for reconstruction.

Lastly, in planning treatment, it cannot be overstated that the socioeconomic impact to the patient must also be brought into the conversation. Understanding a patient's individual functional goals and needs is important in that it may drastically alter a surgeon's proposed surgical course. Some patients may seek expeditious return to heavy work without multiple surgeries, which will result in a very different reconstructive plan altogether. These socioeconomic factors may also result in variable access to postoperative therapy and necessary follow-up.

Physical Exam

Initial examination should focus on vascular status distal to injury as this will ultimately determine the urgency for definitive treatment and overall prognosis. Capillary refill is a helpful tool to assess digit or extremity perfusion. However, it is important to recognize that capillary refill alone may at times be deceiving as stagnant blood returning to a site of compression may mimic a “normal” refill time. As such, an understanding of the spatial relationship between injury and adjacent critical structures is an important adjunct. A pale color with poor oxygen saturation and lack of capillary refill, turgor, or bleeding represents compromised arterial inflow. In contrast, dusky color with brisk capillary refill and dark bleeding is indicative of venous congestion. Larger vessel perfusion within the upper extremity may be assessed via Allen's test or handheld Doppler.

Examination of skeletal injuries is typically completed via plain radiographs. In cases of amputation, it is helpful to image both the part as well as proximal stump to understand degree of injury. Advanced imaging such as computed tomography or magnetic resonance imaging is rarely indicated for acute trauma. In gross skeletal deformity where fracture or dislocation results in circulatory compromise, these injuries should be reduced, when possible, prior to transport. Appropriate tetanus prophylaxis should be given, and intravenous antibiotics started at the time of triage. First-generation cephalosporins will typically provide adequate coverage against typical skin flora pathogens; however, in cases of heavy contamination, additional Gram-negative coverage should be considered.

A standardized evaluation of musculotendinous system should be employed with attention to any disruption of normal finger cascade. In cases of large complex injury, this may prove challenging due to pain or lack of visualization. In these situations, anticipated disrupted structures based on available exam findings should be noted and definitive confirmation will be completed at the time of operating room (OR) exploration.

Nerve injuries are evaluated by both motor and sensory function. Testing of motor function of median, radial, and ulnar nerves is assessed by active motion of both extrinsic and intrinsic muscles. Sensory nerve function along dermatomal distributions is performed with two-point discrimination or Semmes–Weinstein monofilament testing. If the site of injury is within the palm or distal, particular attention is given to digital nerve function. Suspicion for nerve injury is typically higher in sharp penetrating trauma and generally much lower in blunt crush injuries.

In cases where hemorrhage is present, hemostasis is best achieved by applying direct pressure to the area to allow for thrombus formation. While a compressive dressing may be needed, we do not recommend tourniquet control unless absolutely necessary as prolonged use will decrease available tourniquet time in the OR. We do not routinely clip or clamp structures in the emergency room for risk of inadvertently injuring adjacent structures or inadvertently shortening the usable length of available vessels and nerves.

If an amputated part is involved, cooling the tissue is the most effective way to prolong viable ischemic time. The preoperative Buncke Clinic protocol consisting of a rectal aspirin, dry or slightly moistened gauze on the amputated part placed on indirect ice, and no digital block, was shown to significantly decrease complication rates during replantation. ³ An important caveat is that all skin bridges should be left intact as they may hold critical draining veins that can support adequate venous outflow in the part and obviate the need for additional venous reconstruction. In these cases, the ischemic part should be wrapped in a moist gauze or towel and left in situ.

Replantation and Revascularization

Indications and Contraindications

Indications for replantation and revascularization have continued to change as surgical techniques advance. ⁴ Generally accepted conditions for replantation distal to the wrist are: (1) thumb amputation, (2) multidigit amputation, (3) partial (transmetacarpal) or complete hand amputations, and (4) any level of digit or hand in children. ⁵ Ideal candidates have sustained sharp guillotine-type injuries which are minimally contaminated. Before surgery, the surgeon must carefully consider the likelihood of viability and functional restoration of the replanted digit or hand in the context of patient goals. That is, will the function of the hand be improved in a meaningful way by replantation compared with merely closing the amputation stump and fitting the patient with a prosthesis.

Thumb amputations have the strongest indication for replantation given the crucial function within the hand. ^{6 7} A thumb replant with intact metacarpophalangeal (MCP) and carpometacarpal (CMC) joint motion can provide adequate thumb function. But even if the interphalangeal (IP) and MCP joints are fused, an intact CMC joint alone still allows for functional key pinch ( Fig. 1 ). As such, thumb avulsion amputations at the level of MCP are candidates for replantation. In cases where replantation is not possible, reconstruction involving acute or delayed great toe transfer should be considered.

Fig. 1.

Thumb amputation through the metacarpophalangeal (MCP) joint ( A ). Preoperative image of amputation thumb and hand ( B ). MCP arthrodesis achieved acutely via crossing 0.045 Kirschner wires (K-wires) ( C ). Thumb replantation, 9 months postop, dorsal hand ( D ). Thumb replantation, 9 months postop, radial hand ( E ). Thumb replantation, 9 months postop, fist.

In multiple digit amputations, we generally advocate for replantation of all suitable amputated digits. In situations where multiple digits have been amputated by crush or avulsion injury and none are in good condition, heterotopic replantation can be considered to prioritize preserving pinch. If completely amputated digits cannot be replanted, a “spare parts” approach can be used for salvage of components to reconstruct other amputated digits.

Single digit replantation indications are controversial. Replanting single digits distal to the flexor digitorum superficialis (FDS) insertion (zone 1) has been shown to restore good function. ⁸ In addition, good functional results are also possible in single digit replantation distal to the distal IP (DIP) joints (Tamai zone I and II). ⁹ In our experience, single digit replantation, even within zone 2 can yield excellent long-term functional results provided appropriate postoperative rehabilitation and timely revisions are performed, including tenolysis and capsulotomy when needed. ¹⁰

Contraindications to replantation and revascularization include: significant concomitant injuries, high comorbid load including psychiatric illness, older patient age with poor rehabilitation potential, multilevel injury within the amputated part, long avulsion injuries, severe contamination, and prolonged warm ischemia time.

Preparing the Amputated Part

Efficient salvage begins at the stage of triage and before patient arrival into the emergency room. Ideally, the patient will be transferred to a specialized, regional center of expertise with qualified and experienced microsurgeons and staff available. ¹¹ Clinical images of the amputated part and radiographs facilitate presurgical planning while the patient is in transport. The OR staff and appropriate anesthesia teams should be notified as far in advance as possible. In cases of transfer, this should be prior to patient arrival at the receiving facility. After the patient arrives in the ED and the decision to proceed with replantation is confirmed, we advocate the surgeon take the amputated part to the OR. To maximize efficiency, the exploration of amputated part begins concurrently as the anesthesia team interviews the patient and before the patient enters the OR for induction.

The OR staff should prepare a back-table for exploration of the amputated part. The surgeon should have available a second set of microsurgical instruments, heparinized saline, micro- and small vascular clip appliers, fine dissection scissors, Adson forceps, fine DeBakey forceps, and 4–0 and 5–0 nylon sutures. A mini C-arm should be available to confirm Kirschner wire (K-wire) placement in the amputated part and a microscope available for fine dissection ( Fig. 2 ).

Fig. 2.

Tagging table setup.

The amputated part is first irrigated with betadine and saline to remove gross contaminants prior to presentation to the back table. If an assistant is unavailable for retraction, the amputated digit is secured to a towel with nylon sutures for counter tension during dissection. Bruner incisions are made and the skin flaps are secured distally using 5–0 nylon sutures. Mid-lateral incisions may be used, but are often discouraged because they may leave the neurovascular bundle exposed, risking desiccation or inadvertent injury in handling. ^{12 13}

Under the microscope, or using loupe magnification, arteries, veins, and nerves are tagged with small and microclips on the back table. In our practice, we commonly use different sizes to denote different structures to facilitate quick matching of paired structures during final repair. In the case of finger replantation, the distal half of a 4-strand core suture is placed into the flexor digitorum profundus (FDP) tendon of the amputated part. Some investigators advocate vein grafting on the back table, but we have not found this technique to be necessary. ¹⁴ Lastly, longitudinal K-wires are placed into the amputated part with care to avoid ensnaring previously tagged structures ( Fig. 3 ).

Fig. 3.

Properly prepared part, prior to patient entering the operating room. Note that all distal structures have been identified, distal sutures are placed in the tendons to be repaired, distal osteosynthesis is in place, and fasciotomies performed.

Finger Replantation

Several sequences of operative repair have been described. The overarching principle is efficient stepwise repair of structures where subsequent repairs do not jeopardize disruption of previously repaired structures. Additionally, the tourniquet should be treated as a valuable resource and used judiciously to minimize overall number of necessary tourniquet runs. If the surgeon is methodical and approaches the operation with a systematic plan in mind, it is often possible to complete all essential components of the case in one tourniquet run ( Fig. 4 ).

Fig. 4.

Zone 1 replantation. ( A ) Long finger amputation distal to the flexor digitorum superficialis (FDS) insertion. ( B ) Long finger replanted.

Bony fixation is typically performed first. In some cases, especially with multidigit replantation, this portion is completed off tourniquet. Skeletal shortening is a useful technique to bring the soft tissue structures into tension-free approximation. Shortening should be performed preferentially on the amputated part to preserve digital length in the case of replant failure. In our experience, using K-wires is most often sufficient and provides a technically simple, streamlined way to move the operation forward to execute the other necessary steps. Our approach typically involves two 0.035” or 0.045” K-wires to achieve fixation and prevent rotational deformity. For distal or pediatric replants, 0.035” or 0.028” K-wires may be used.

Following bony fixation, the extensor tendon is then repaired using one to two figure-of-8 sutures. During this portion of the procedure, care is taken to both identify and preserve the dorsal veins which will later be used for outflow.

After the extensor mechanism is repaired, the hand is placed in supination and the tourniquet is inflated. The FDP tendon repair is completed next to set the appropriate tension and posture of the digit before repairing the microvascular structures. Modest improvement in postoperative function may be seen with the additional repair of FDS, ¹⁵ but this repair takes additional precious time and often does not add substantial digital excursion to the final outcome in our experience. Additionally, an additional FDS repair may greatly complicate future flexor tenolysis (particularly in zone 2), which is often necessary to maximize function in digit replants. As such, we often forego repair of the FDS in finger replantation. The FDS tendon may be excised at the time of replantation or preserved as a source of future tendon graft.

Following flexor tendon repair, the microsurgical portion of the operation begins. We prefer to begin with the arterial anastomoses. At this juncture, it is important to consider thorough debridement of injured segments of the vessels. After washing with liberal amounts of heparinized saline, both ends should be examined under high magnification. The decision regarding extent of vessel debridement can be challenging. After an avulsion injury, intimal damage can extend 3 cm or more beyond the point of vessel rupture, which is often underappreciated. ¹⁶ Intimal fibrillation, petechiae, cracks, or intraluminal white clots are all indications of extensive vessel injury and should be debrided away to healthy appearing lumen. It is preferable to trim vessels under the microscope with the tourniquet inflated and to make an expeditious decision about the length of resection and potential need for vein grafts.

Mobilization of the digital arteries by clipping side branches may obviate the need for a vein graft. This contrasts significantly with digital nerves, which exhibit little stretch even with significant mobilization. Should a vein graft be necessary, we prefer distal volar forearm veins for digital arteries. Dorsal foot veins and the greater or lesser saphenous vein may be used for more proximal injuries. Although the tourniquet may be deflated to check for inflow, this step is often unnecessary in experienced hands because the morphologic appearance of the vessel and its lumen is sufficient to determine adequacy of arterial debridement. If any doubt exists, the tourniquet may be deflated to ensure adequate flow, and then reinflated to assist with the arterial anastomosis. The anastomosis is most commonly performed under tourniquet using interrupted 9–0 or 10–0 nylon sutures (11–0 nylon sutures may be needed for very distal replants). One option is to use double-opposing clamps to facilitate back wall repair, whereas another technique uses Serafin clamps proximally and distally while performing a free-hand anastomosis.

Following the arterial anastomosis, attention is turned to the digital nerve repair, which is most commonly performed under tourniquet control. This step should be performed with a similar attention to detail as protective sensation is crucial in the overall long-term functional success of replantation. A core tenant in digital nerve reconstruction is adequate debridement out of the zone of injury to where a contiguous epineurium encapsulates healthy fascicles. The repair should yield a tension-free neurorrhaphy through digital range of motion. If this is not possible, then nerve grafts are often required. Options include nerve conduits for short gaps (< 6 mm), as well as autograft and allograft for longer gaps. Autograft options include the sural nerve, superficial peroneal, posterior interosseous nerve, or nerves harvested from spare parts. ¹⁷ Size mismatch and donor site morbidity are important considerations. In recent years, the use of nerve allografts in our practice has greatly supplanted the use of autografts in digit replantation. ¹⁸

Following arterial and nerve repair, volar skin closure is performed with 4–0 chromic suture. The closure should remain tension free to avoid compromising patency of underlying repaired vessels. Split-thickness and full-thickness grafts from spare parts or other donor sites within the hand and forearm can be used. Once the volar structures are repaired, the tourniquet may be kept inflated or taken down depending on the amount of time elapsed. The authors prefer to keep the tourniquet insufflated for as long as possible and will extend the tourniquet time up to 150 minutes, if necessary.

Upon completion of volar closure, the hand is then pronated and as many venous anastomoses are performed as possible while the tourniquet remains inflated. Additional anastomoses may be performed once the tourniquet is released. In some cases, deflating the tourniquet may prove beneficial as vein distention after successful reperfusion may aid in visualization for repair. If vein grafts are used for venous drainage, precise attention should be paid to vein length to avoid kinking during closure as they may dilate and distend significantly. ¹² Suitable volar veins may also be used for venous outflow, particularly in distal replants (e.g., Tamai zone I). In these cases, all the microsurgery (artery, nerve, and vein) may be done in the same field without need to pronate the hand.

Distal Replantation

With the advancement of microsurgical techniques and recognition of more optimal functional and aesthetic outcomes, flexor zone I amputations are considered a good indication for replantation. ¹⁹ Several excellent classification schemata have been described for distal digital replantation. The system proposed by Tamai further divides to zone I and II at the base of the nail and DIP joint, respectively. ²⁰ Distal replants can be in some ways more straightforward as fewer structures require repair. However, available vessels are fewer and smaller in caliber, therefore may be more technically challenging with a need for “supermicrosurgery” techniques.

Tamai zone I includes amputations distal to the lunula. The digital arteries typically coalesce at this level to form three or more longitudinal pulp vessels which are the primary targets for reestablishing inflow. The central pulp artery is typically the largest of these vessels, measuring 0.3 to 0.7 mm in diameter. ²¹ In some circumstances, a volar vein may be present and can be utilized for sufficient venous outflow. At this level, the digital nerves have trifurcated into distal branches that cannot and do not need to be repaired. This level is also distal to the flexor and extensor tendon insertions, obviating the need for tendon repair. Bony fixation is straightforward with one or two longitudinal K-wires. If little or no bone is present within the part, especially in pediatric instances, stabilization can be sufficiently achieved with skin suturing alone. ²² Several 5–0 chromic sutures are used to loosely approximate the skin.

In Tamai zone II amputations at the level of DIP joint, arterial anastomoses become technically more feasible. More importantly, the superficial dorsal veins first become available for repair. ²³ Just beyond the DIP joint, the digital nerve usually gives off two branches on each side—the proximal subungual branch to the proximal nail fold and the distal subungual branch. When these branches are not available, repair is not required ( Fig. 5 ).

Fig. 5.

Tamai zone II fingertip replantation. ( A ) Tip amputation, Tamai zone II. ( B ) Amputated part with digital artery and nerve under the operative microscope. ( C ) Tamai zone II replant, prior to revascularization. ( D ) Tamai zone II replant, following revascularization. ( E ) 6-month follow-up, lateral. ( F ) 6-month follow-up, palmar. ( G ) 6-month follow-up, range of motion.

In both Tamai zone I and zone II distal finger replants, artery-only replantation is frequently employed due to limitations in suitable vein candidates. ²⁴ Our protocol utilizes intravenous heparin (range 500–1,000 U/h) initiated at the time of arterial anastomosis. To establish early venous outflow, a fish-mouth incision at the pulp tip away from the anastomoses is made. The area is serially treated with heparin pledgets, leech therapy, and/or scrubbing by nursing staff to augment bleeding and relieve acute decongestion. Heparin is titrated to promote a controlled bleed, or a minimum bleed to allay concerns about inflow competence, not to satisfy a target therapeutic partial thromboplastin time. Before leech placement, the patient should receive an antibiotic to prophylactically treat Aeromonas hydrophila . By postoperative day 6, we no longer promoted bleeding by these maneuvers. ²⁵

Transmetacarpal Replantation

The sequence of operative repair in transmetacarpal replantation is almost the same as that in multiple-digit replantation, but the approach for vessel repair is different. A vein-first approach is typically used as the dorsal hand veins are large and readily visible. In these cases, the veins are repaired after extensor tendon repair so that the dorsal skin can be provisionally closed to protect the anastomoses on supination.

Typically, the common digital arteries to the index and middle finger, the ring and small finger, and the princeps pollicis artery are repaired. Y-shaped vein grafts from the distal volar forearm or the dorsal foot can be used to reconstruct the superficial palmar arterial arch and provide arterial blood flow to two distal common digital arteries. Replantation at this level requires additional hemostasis of the distal palmar metacarpal arteries that communicate with the common digital artery to prevent retrograde bleeding into the palm after the common digital arteries are repaired. In cases of severe crush mechanism, it is not uncommon for significant intrinsic muscle necrosis to develop, which may require additional serial debridement and soft tissue reconstruction. If a thumb amputation is at the level of first metacarpal, proactively preventing first webspace contracture is beneficial for long-term functionality. In these situations, we recommend temporary fixation of the first intermetacarpal space and splinting the thumb in the palmar abducted position.

Wrist Replantation

For amputations through the carpus, 0.062” Steinman pins are typically used for bony fixation. In appropriate candidates, a proximal row carpectomy may also be performed to achieve appropriate shortening. If the possibility of wrist motion remains, the wrist flexor and extensor tendons and wrist capsule should be repaired. If wrist motion is impossible, the wrist should be fused in a neutral position. The carpal tunnel is typically opened to repair the flexor tendons and median nerve in a wide operative field. The deep motor branch of the ulnar nerve is identified distally and repaired. Dorsal fasciotomy of the interosseous muscles should be performed in anticipation for reperfusion swelling. Both the radial and ulnar arteries and at least two to three veins should be repaired.

Forearm Replantation

When assessing amputation at the level of forearm and proximal, it is important to first consider the structural integrity of the hand. If the hand of the amputated part has been severely damaged and reasonable function cannot be achieved, then the amputated part should not be replanted.

The volume of tissue within a forearm or proximal replant is substantially larger than in cases of finger replantation. With increasing proportion of muscle mass, the amputated part becomes much less tolerant of ischemia as a whole. In situations where the ischemic period is borderline, one of the first maneuvers to extend the tolerable period of ischemia is to perform a temporary arterial shunt to the amputated part using a Sundt or ventriculoperitoneal shunt. ²⁶ The temporary shunt allows for time to obtain and prepare vein grafts where needed, label other vessels and nerves for repair, secure bony fixation, and complete a thorough debridement. Within forearm amputations, the radial artery is typically shunted to allow for back bleeding through the ulnar artery. When shunt perfusion is initially attained, the veins are not immediately connected, and the blood is allowed to run out of the arm to prevent systemic recirculation of accumulated hazardous metabolites within the ischemic part. Blood products should be readily available because this maneuver can result in significant blood loss. Early transfusion is preferable to avoid use of vasopressors and should be communicated to the anesthesiology team at the beginning of the operation.

In cases of clean, sharp amputation arriving in the OR 2 to 3 hours after injury, temporary shunting may not be required. In these scenarios, the part is typically prepared on the back table analogous to a finger replant. Devitalized muscles within the zone of injury, especially in crush or avulsion injuries, are likely to progress to necrosis despite revascularization and are prone to cause eventual infection in the replant. Thorough debridement of these nonviable areas at the time of replantation is crucial. In this process, suitable vessels and nerves should be dissected free with adequate length to allow for more degrees of freedom in repair. Free ends should be examined under the microscope to confirm suitability and tagged before beginning skeletal fixation.

For amputations through the distal forearm, a distal radius plate and a distal ulna plate, if necessary, are applied on the back table. For amputations through the diaphyseal radius and ulna, 3.5-mm plates or a metadiaphyseal distal radius plate are used ( Fig. 6 ). Bone shortening is typically completed with oscillating saw prior to plating. Amputations through the elbow, or highly contaminated injuries, will typically require external fixation in the acute setting. Extensive distal fasciotomies should be performed on the back table in a bloodless field in anticipation for reperfusion swelling. Skeletal fixation is typically completed first and followed by arterial repair.

Fig. 6.

Osteosynthesis for forearm level amputation, 3.5 mm low contact-dynamic compression (LCDC) plate fixation. ( A ) Anteroposterior (AP) view. ( B ) Lateral view.

In the forearm, when possible, both arteries are repaired. If there is a large gap in the vessels, either the radial or the ulnar artery is repaired with a vein graft and the circulation is reassessed. In crush or avulsion injuries where a large area of soft tissue coverage may also be required, the second unused vessel is commonly utilized as inflow for free flap coverage. As many veins as possible are anastomosed in major replants. While the superficial venous system is often larger and easier to repair, the deep system of brachial, radial, and ulnar artery venae comitantes are capable of significant venous outflow as well. At the completion of venous anastomoses, the replanted part should be carefully reassessed for venous congestion. If the part demonstrates inadequate outflow, additional veins must be repaired ( Fig. 7 ).

Fig. 7.

Forearm level amputation. ( A ) Amputated part. ( B ) Amputation at forearm level. ( C ) Replanted forearm level amputation, volar. ( D ) Replanted forearm level amputation, dorsal. ( E ) 1-year follow-up, volar. ( F ) 1-year follow-up, range of motion. ( G ) 1-year follow-up, dorsal.

Osseous Reconstruction

Osseous reconstruction of the upper extremity has evolved over the last half century from percutaneous fixation and rudimentary external fixation to complex internal osteosynthesis, bone transport, and free osseous flap reconstruction. Advances have been such that rarely is the osseous injury the primary determinant of salvageability in complex upper extremity injuries.

The initial management of osseous injuries should focus on bony stabilization, temporary or permanent depending on the clinical scenario, and adequate debridement of bone and soft tissue. While closed injuries may be addressed in strict accordance with Danis' principles of internal fixation, ²⁷ open and contaminated open injuries often require provisional fixation until the wound is amenable to closure, allowing for a stable limb while debridement is performed. Only after aggressive soft tissue and bony debridement has been performed, are the true reconstructive requirements apparent.

We approach osseous fixation and bony reconstruction as the necessary foundation upon which upper extremity salvage is built; however, this does not imply that techniques are necessarily complex. In the acute setting, the goal is to attain sufficient stability to allow for repair of injured vessels and soft tissues. K-wires are particularly useful in the traumatic setting as they are widely available, easily and quickly placed, and are ultimately removable, allowing placement in a contaminated traumatic field. While plating, 90/90 wiring and external fixators have been applied acutely in the injured hand, the use of K-wires remains our primary method of fixation in these injuries and particularly in replantation cases. External fixators subserve a similar role in stabilizing contaminated injuries proximal to the wrist, prior to the placement of definitive fixation; however, their prominence can make additional reconstruction challenging with respect to patient positioning and accessibility. Irrespective of technique, fixation should be expeditious, allowing the surgeon sufficient time for soft tissue and vessel repair ( Fig. 8 ).

Fig. 8.

Crush, degloving injury of the forearm. Illustrative of sequence of fixation. ( A ) Initial presentation with both bone forearm fracture and gross contamination with soft tissue loss. ( B ) Temporary fixation with rudimentary external fixator to allow for stabilization and debridement. ( C ) Forearm following adequate soft tissue debridement. ( D ) Radius fixation with 3.5 mm low contact-dynamic compression (LCDC) plate. ( E ) Ulnar fixation with 3.5mm limited contact-dynamic compression (LCDC) plate. ( F ) Soft tissue reconstruction with free latissimus dorsi flap. Note definitive hardware placement at the time of definitive soft tissue reconstruction.

Injuries that involve the joints provide additional complexity and the decision between arthrodesis and attempted joint preservation must be made. These decisions typically do not need to be made at the time of the acute injury and are better informed after the patient has healed the initial injury and the surgeon has a better sense as to level of patient motivation and functional requirements. In general, we favor preservation of motion, even in the form of a pseudoarthrosis, whenever possible. These will often be painless and quite stable, particularly in the replanted digit. Should the joint prove to be painful or unstable, arthroplasty or arthrodesis may then be performed. DIP joints as well as the thumb MCP joints are well-tolerated sites of arthrodesis. Wrist arthrodesis is also well tolerated in patients who do not require the tenodesis effect of wrist motion to power finger motion. Thumb IP and index, proximal IP joint arthrodesis are moderately tolerated but will be performed when necessary. Proximal IP joint and to a greater extent, finger MCP joint arthrodeses are poorly tolerated and should generally be avoided whenever possible. Traumatic patients are often good candidates for joint arthroplasty as they generally have good bone density and often limited but stable digits.

Osseous Reconstruction with Bone Flaps

Comfort with basic bone flaps will allow the reconstructive surgeon to salvage a host of heretofore unsalvageable bony injuries. Vascular anatomy of the upper extremity is very predictable and less prone to disease in comparison to the lower extremity. Our primary arterial inflow choice is the radial artery due to its reliable venae and proximity to the cephalic vein. The ulnar artery may be utilized as well; however, corresponding venous drainage is often more difficult to find on the ulnar side of the forearm. The dorsal branch of the radial artery within the first webspace is ideal for osseous reconstruction within the hand and wrist, while end-to-side anastomoses to the radial artery is useful for forearm reconstruction or when the zone of injury is large.

The two workhorse bone flaps for reconstruction are the fibula and medial femoral condyle (MFC) flaps. The fibula is particularly useful for long bone reconstruction and provides an excellent size match to the radial and ulnar diaphyses ( Fig. 9 ). The MFC is an excellent choice for addressing nonunion, achieving wrist arthrodesis, and addressing avascular necrosis.

Fig. 9.

Segmental radius and ulnar reconstruction with a free fibula bone flap. ( A ) Planned fibular harvest for both bone forearm reconstruction. ( B ) Free fibula flap, intervening bone segment denuded for removal. ( C ) 6-cm ulnar reconstruction. ( D ) 8-cm radius reconstruction. ( E ) Fibula bone flap in place reconstructing 8 cm radius and 6 cm ulnar defect simultaneously.

The free fibula is a robust bone flap that can be used to reconstruct the long bones of the arm and forearm, facilitate carpal fusion in the setting of substantial bone loss, and even reconstruct metacarpals. All but the proximal and distal 6 cm can be harvested on the vascular pedicle consisting of the peroneal artery and venae comitantes. This long segment of bone may be harvested with an overlying skin paddle based on cutaneous perforators and the flap may be customized with osteotomies to alter the shape while maintaining perfusion. The pedicle is relatively short; however, its reach can be effectively lengthened by removing proximal bone.

The MFC is an equally robust flap that offers cortical as well as cancellous bone as well as a vascularized periosteal cuff when necessary. The flap is based on the descending genicular artery arising from the superficial femoral artery. The medial superior genicular artery can be alternatively used; however, this pedicle is substantially shorter and typically smaller than the descending genicular ( Fig. 10 ).

Fig. 10.

Medial femoral condyle (MFC) bone flap. ( A ) MFC in situ, note descending genicular artery with associated vascular arcade. ( B ) MFC harvested from knee. ( C ) MFC prior to inset in scaphoid nonunion with proximal pole avascular necrosis.

Soft Tissue Reconstruction

Successful reconstruction of the upper extremity relies upon provision of soft tissue coverage. Given the functional demands of the upper extremity, this soft tissue coverage must be durable, supple, and stable, allowing for motion while protecting and nourishing the vital structures beneath. No complex bony, tendinous, vascular, or nerve reconstruction will be of value, if the soft tissue environment for healing is deficient.

Flap choice is dictated by a host of considerations. In general, wound size and necessity for particular pedicle length often narrows the available options. Additional considerations include tissue type, contamination of the wound, reliability of the patient, and tolerance of the patient for secondary operations. While viewed as antiquated by some, we generally favor muscle flaps for reconstruction and employ fascial and fasciocutaneous flaps in certain, selected scenarios. Muscle flaps provide tremendous flexibility with regard to flap size and pedicle length, while providing a robust, highly vascularized tissue bed to facilitate healing. These flaps can typically tolerate significant wound contamination and can survive the noncompliant patient. Many point to poor aesthetic results with muscle flaps; however, with time, these flaps contour quite nicely and skin graft overlying them can match the surrounding skin quite well. We find that a muscle flap, given time, often provides superior aesthetics to a thick fasciocutaneous flap that may require multiple revisions to attain an acceptable contour ( Fig. 11 ). Our workhorse muscle flap for large defects of the upper extremity remains the latissimus dorsi or partial superior latissimus. The pedicle is long and large allowing for anastomoses outside of the zone of injury and there is simply no other flap that can provide the same surface area of coverage. The serratus muscle may be included to increase available flap surface area or may be used in isolation should a small, thin muscle flap with a long pedicle be desired. In situations where only a small amount of muscle is required and the pedicle can be short, the gracilis flap fulfills these parameters.

Fig. 11.

Latissimus dorsi reconstruction of large dorsal hand wound. ( A ) Crush, degloving injury of left dorsal hand and wrist. Thumb required revascularization. ( B ) Postrevascularization and debridement. ( C ) Latissimus flap, radial view. ( D ): Latissimus flap, dorsal view. ( E ) 4-year follow-up, no revisional surgery.

Fascial flaps in combination with a skin graft can be quite useful in reconstruction of the palm and dorsal hand. Use of a fascial flap has the distinct advantage of reducing thickness that is often the Achilles heel of fasciocutaneous flaps. Our preferred fascial flaps are the dorsal thoracic fascia (DTF) ( Fig. 12 ) and radial forearm fascial (RFF) flaps ( Fig. 13 ). Anterolateral thigh (ALT) fascial flaps, while reasonable, have proven somewhat less reliable and tend to be slower to heal compared with the DTF and RFF flaps. Fasciocutaneous flaps maintain similar indications. The ALT flap, in thin patients, is quite useful in resurfacing the dorsal hand as well as to address forearm soft tissue defects, particularly when hair-bearing skin is desired. The ALT in patients with thicker thighs tends to become cumbersome, requires harvest of a much larger flap to attain skin closure, and will necessitate multiple revisions. For these reasons, we generally avoid the ALT in patients with a thigh pinch much greater than 1 to 2 cm. In these patients a contralateral radial forearm free flap is a more viable option if a fasciocutaneous flap is desired. The radial forearm has the distinct advantage of a robust vascular supply and a long available pedicle.

Fig. 12.

Dorsal thoracic fascia (DTF) reconstruction of dorsal hand wound. ( A ) Dorsal hand wound. ( B ) Dorsal thoracic fascia flap. ( C ) DTF flap inset. ( D ) DTF flap with skin graft.

Fig. 13.

Free radial forearm fasciocutaneous flap. ( A ) Radial forearm fasciocutaneous flap design. ( B ) Left hand wound. ( C ) Radial forearm flap inset, syndactylizing the index, long, ring, and small fingers.

Conclusion

Treatment paradigms for upper extremity trauma have changed over time with advents in new technology and surgical techniques. While the traditional mainstay in mangled extremity care has been amputation, many clinical situations are now suitable for salvage. Complex upper extremity trauma remains one of the most challenging areas in hand surgery today. Critical key concepts include thorough debridement of devitalized tissue, restoration of perfusion to devascularized tissue, rigid skeletal fixation, and establishment of a well-vascularized soft tissue envelope. Ultimately, achieving good outcomes requires broad expertise in several disciplines including plastic surgery, orthopedic surgery, and vascular surgery. This process begins with understanding initial injury mechanics, identification and cataloguing of injuries, and prioritizing a series of treatment options over the period of months to years to restore acceptable functional use in daily activities.