Early return to motion is key to achieving the best outcome.
Rigid internal fixation methods make early return to motion possible.
The choice of treatment is determined by the specific circumstances of the fracture, balancing the benefit of anatomic reduction with minimal soft tissue injury and patient expectation.
Methods of fixation range from simple casting, closed reduction and internal fixation (CRIF) with percutaneous Kirschner wires (K-wires), to open reduction and internal fixation (ORIF) with screws and sometimes plates, and for mutilating injury combining ORIF and external fixation.
Failure to obtain a satisfactory closed reduction is an indication for ORIF.
Collaboration between the surgeon and therapist is essential to achieving the optimal outcome of hand fracture management.
The metacarpals and phalanges extend from the carpus and project the carpal arch as they shape the palm and digits ( Fig. 30-1 ). As the hand interacts with the environment, skeletal trauma may result. Fracture renders the hand effete with disruption of the stable aligned skeleton. Much of the remarkable function is lost. A practical approach to fractures of the shaft of the metacarpals and the phalanges follows, including multiple methods of treatment. It is important to consider many factors in determining the ideal treatment for a given patient with a specific fracture. To achieve the best outcome, contemporary teaching supports an early return to motion made possible by rigid internal fixation methods. The enthusiasm for this surgical philosophy is tempered by the inherent soft tissue injury caused by surgical dissection. For certain fractures closed reduction and pinning gives a more predictable favorable result with less risk. Our choice of treatment is determined by the specific circumstances of the fracture balancing the benefit of anatomic reduction with minimal soft tissue injury and patient expectation.
A careful and comprehensive hand examination is performed prior to treatment. An inspection of the hand is made noting the precise location of swelling, ecchymosis, abrasions, lacerations, and deformities. Gentle palpation of the bony and joint surfaces is done noting the areas of maximum tenderness. Acute injuries are tender. It is important to evaluate adjacent joints and bones in order to avoid missing concurrent injury.
Rotational deformity is best assessed with finger flexion. If the injury is too painful, sometimes the nail plate orientation suggests the rotational deformity, but this is not as precise as asking the patient to flex the digits.
Metacarpal Shaft Fractures
The digital metacarpals reside in the hand and are surrounded by the interosseous and abductor digiti minimi muscle bellies. Extrinsic extensor tendons glide smoothly over the dorsal surface of these bones separated by thin fascial planes. Fractures of the metacarpal shaft often disrupt the continuity of this soft tissue “envelope.” The care of bony fractures includes treating the injured surrounding soft tissues. The surgical treatment can result in adhesions, which limit motion.
Fractures from the neck to the middle third of the metacarpal shaft typically occur after a punch or when the hand is struck by a hard object. The dorsal apex of the fracture causes a visible, palpable, and tender deformity. If this patient is not seen until the day after injury, the surrounding swelling may obscure the deformity.
Angular deformities due to neck and shaft fractures often are undertreated either due to misinterpretation of the literature or patient preference. There is a distinction between impacted head and neck fractures, for which up to 40 degrees of angulation may be acceptable, and angulated distal shaft fractures, which are usually not acceptable with more than 20 degrees of deformity. A residual unsightly dorsal bump can interfere with excursion of the overlying extensor tendons and weaken grip strength. With the metacarpal head flexed into the palm, in addition to its prominence interfering with palmar grasp, the patient experiences loss of extension and appears to have an “extensor lag.”
Our preference is to reduce all angulated metacarpal shaft fractures of 20 degrees or more or if the deformity is unacceptable to the patient. If the apex is a palpable deformity, it will remain palpable unless reduced. In true impacted neck fractures in which the head is rotated down, up to 40 degrees can be accepted with little if any loss of function.
If the patient punched another in the mouth, “teeth marks” may be seen in the dorsal skin over the metacarpal head. This injury is treated as a human bite wound. A wound extending to the fracture constitutes an open contaminated fracture. This injury is treated with extensive débridement (excision) of all contaminated layers of the wound and IV antibiotics. Following reduction, fixation may be necessary to stabilize the fracture. The decision to use fixation devices such as a K-wire or plate in an open fracture is a judgment call. One choice is to postpone definitive fracture fixation until the wound is satisfactorily healing and no longer contaminated. However, an unstable fracture in an infected or severely contaminated wound is the worst combination, and in this instance the fracture may be pinned with a longitudinal K-wire.
If the wound is untidy and the preference is not to approach the fracture through the metacarpal head, the pin may be placed in an antegrade fashion. Jorge Orbay developed a technique and a device to place an intramedullary pin antegrade from the base of the metacarpal through the shaft and into the metacarpal head. , This method offers limited advantages for an uncomplicated closed shaft fracture and often requires removal of a buried bent pin at the base of the metacarpal, which may require a return to the operating room.
Closed Reduction of Metacarpal Neck and Shaft Fractures
Most of these fractures can be reduced by simple methods, especially if the patient is treated within 7 days of injury. A well-fitting cast application is an acceptable method of treatment. The challenge is to maintain the reduction, keep the patient’s hand comfortable, maintain the metacarpophalangeal (MCP) joint in at least 60 degrees of flexion, and still allow adequate radiographic imaging to assess the position of the fracture and identify any loss of reduction.
The sedated patient is in the supine position with involved arm comfortably abducted on an arm table. A tourniquet is applied to the upper arm but usually not inflated for this procedure. The upper extremity is prepared and draped in the usual sterile fashion. Satisfactory anesthesia is achieved with either wrist or axillary block.
We prefer to use wrist block anesthesia. For the small finger MC ( Fig. 30-2 ) a combination of an ulnar nerve and dorsal sensory ulnar nerve block gives complete anesthesia. For the ring finger MC, we add the median and superficial radial nerve blocks at the wrist. Once anesthesia is achieved, a closed reduction is performed. For most MC neck transverse or short oblique shaft fractures, reduction is performed as follows.
Apply longitudinal traction to the involved digit, then flex the MCP joint. Dorsally directed pressure is applied by the digit through the MP head. Pushing up on the MC head should straighten out the angular deformity. This reduces the dorsal apex of the fracture to its normal gentle curve. Any rotational deformity is reduced at this time. The reduction can be held by pushing up on the flexed proximal interphalangeal (PIP) joint with the surgeon’s thumb and down on the apex of the fracture with the index and middle fingers. A C -arm image intensifier and a power drill are used to maintain the reduction with a longitudinal K-wire. This is the CRIF technique.
Satisfactory reduction is verified with the C -arm. Exposure of the surgeon and patient’s hands to the x-ray beam is minimized. The spread of the substantive x-ray exposure is about 15 inches wide. , Staying 3 feet away from the beam decreases radiation to 25%. The maximum exposure is on the side facing the image intensifier where maximum scatter occurs.
Using a power drill ( Fig. 30-3 ), a 0.054-inch diameter K-wire is drilled through the metacarpal head and down the shaft. There is a tendency to be too volar and ulnar with the initial K-wire. The intent is to deliver the wire to the base (subchondral bone) of the MC but not cross the carpometacarpal (CMC) joint. Once the position of the fracture and K-wire are verified, the K-wire is cut off 3 mm outside the skin.
The resultant position of the MCP joint is at least 60 degrees of flexion. The flexed position maintains the length of the MCP joint’s collateral ligaments avoiding an extension contracture. Skin tension must be assessed and released around the protruding wire ( Fig. 30-4 ). The tight skin reflects the direction of the tension. Incise the loose skin ( Fig. 30-5 ) in line with the tension to release it. This prevents an infection around the pin site. Satisfactory reduction of the fracture and position of the K-wire are verified with the C -arm in both the anteroposterior and lateral planes ( Fig. 30-6 ).
The pin site is covered with Xeroform gauze. A short arm cast is applied for 3 weeks, immobilizing the involved and adjacent digits. In compliant patients, the cast can be shortened at 1 week to allow some passive PIP motion. The cast and pin are removed at 3 weeks. Using a heavy needle holder, spin the wire then apply longitudinal traction as the wire is extracted.
Most MC shaft fractures treated this way are healed enough to remove the K-wire by 3 weeks, that is, if the fracture is not tender despite the radiograph not reflecting healing. In this instance, the fracture is healed enough to allow the return of motion for the next 3 weeks. It is a little difficult to get all the MCP joint extension immediately after wire removal. The patient is encouraged to perform active assisted range-of-motion (ROM) exercises. Buddy taping to the adjacent finger facilitates the motion for the first few weeks after cast removal. Some patients require a removable molded ulnar gutter orthosis during the transition for the first week out of the cast. Six weeks after CRIF, more resistive exercises and weight-bearing activities can progress as tolerated.
CRIF technique can be applied to transverse and short oblique fractures for all the MCs. When satisfactory closed reduction cannot be achieved, as in cases with a long obliquity, segmental fragments, or soft tissue interposition, ORIF is preferred.
Open Reduction with Internal Fixation
Certain MC shaft fractures are preferably treated with ORIF. The long oblique fractures of the MC shaft are amenable to ORIF with interfragmentary self-tapping screw fixation. Torque forces create spiraling fractures down the MC shaft and disrupt the attached interosseous muscles. These adjacent muscles can interpose in the fracture and prevent a satisfactory closed reduction. Also these attached muscles contribute to shortening of the unstable fracture.
The goal of ORIF is to accurately restore the anatomy with enough stable fixation that the motion can begin before fracture healing. If stability cannot be achieved, then motion must be delayed until healing takes place.
MC shaft fractures are best approached through a longitudinal dorsal incision set between the MCs. , The patient is positioned, prepared, and draped as with CRIF but axillary (or supraclavicular) block is preferred. The arm is exsanguinated and a tourniquet applied at the upper arm, set 100 mm Hg above systolic pressure, not to exceed 300 mm Hg.
A longitudinal skin incision is made between the extensor tendons. The extrinsic extensor tendons are gently retracted. A longitudinal incision along the bony cortex is made, sharply dissecting the periosteum and muscle attachments off the fracture to expose just enough of the fracture. In an effort to preserve the bone’s blood supply and promote healing, all soft tissue attachments to fracture fragments are preserved. Longitudinal traction is applied and the fracture reduced. Derotation and restoration of length are addressed.
It is especially gratifying to spend the time to reduce the fracture anatomically. As little as 1 mm of missed rotational deformity may cause an unsightly rotatory deformity of the digit. The average circumference of a MC is less than 3.6 cm. Each millimeter of rotational misalignment represents at least 10 degrees of rotational deformity. Usually, more than 5 degrees is unacceptable clinically and will interfere with function.
Once reduced, a fracture clamp is placed and then a K-wire is provisionally fixed perpendicular to the fracture. Imaging verifies satisfactory reduction. The provisional K-wire is placed to indicate where the interfragmentary screws will go. Nondisplaced fissures in the bone are carefully identified, and placement of a screw in a fissure is avoided. The screws are placed perpendicular to the plane of the fracture as much as possible and well spaced along the fracture. The holes are drilled, on the near cortex overdrilled, so compression can be applied across the fracture. It is preferable to direct the screw from the smaller to the larger fragment. Placing a screw within one screw head diameter of the fracture line, an adjacent screw, or near the apex of the fracture fragment is avoided ( Fig. 30-7 ). Countersinking the interfragmentary screws prevents irritation of the overlying tendons and improves fixation of the diaphyseal fracture. , This is particularly important for fixation of the phalangeal shaft fractures (see section on Phalangeal Shaft Fractures ). The size of the screw is in the range of 1.3 to 1.5 mm in diameter but is determined by the anatomy of the particular patient.