Hand, Wrist, and Forearm Injuries
Kenneth J. Noonan, MD, MHCDS
Donald Bae, MD1
Guru:
THE GURU SAYS…
A very small percentage of hand injuries accounts for most of the complications and suboptimal outcomes. Learn to identify the “problem players” to stay out of trouble. When you hear hoofbeats, think about the zebras as well as horses!
DONALD BAE
General Principles
Hand, wrist, and forearm injuries are among the most common injuries sustained by children. Although not life-threatening and usually not debilitating, they may be a frequent source of management trouble due to the sheer volume seen by most orthopaedists caring for children. Most injuries can be treated successfully and will heal uneventfully; however, careful attention to certain principles of diagnosis and management is critical to a consistently good outcome. In hand injuries, 75% create no problems, but 25% need careful diagnosis and treatment. To stay out of trouble, the orthopaedist must promptly recognize and treat problem fractures early.
Hand and Wrist Injuries
Although a pediatric orthopaedist or a general orthopaedist caring for children can handle the vast majority of hand injuries in children, it is important to know which cases should be transferred directly to a hand surgeon.
THE GURU SAYS…
You can see a lot just by looking! Taking advantage of the tenodesis principle will allow you to identify flexor tendon injuries as well as malrotated fractures, things that you cannot diagnose radiographically.
DONALD BAE
Physeal injuries represent 10% to 40% of all hand fractures. Fortunately, growth arrest is very rare. To stay out of trouble, it is important to recognize that an apparent “tendon disruption” may instead be a physeal fracture in a young child (Fig. 8-1). The flexor digitorum profundus inserts onto the distal phalanx and the flexor digitorum superficialis inserts onto the middle phalanx. The extensor tendons insert onto the epiphysis of the distal phalanges.
Evaluation of the pediatric hand can be challenging. It’s always a good idea to exam the uninjured hand first in order to gain trust. Questions should be general and with simple queries such as if the fingers feel sleepy or if they feel the same as the uninjured side. The tenodesis concept is critical to the examination. The orthopaedist should check the digital cascade at rest and with tenodesis wrist motion. This maneuver will call attention to the diagnosis of malrotated fractures and flexor tendon injuries. Fingers that don’t extend or flex with wrist flexion may indicate an occult tendon injury.
THE GURU SAYS…
Use all your tricks! If a child will not allow you to examine the digit or move the wrist for tenodesis, you can compress the flexor muscles in the forearm—outside the zone of injury—to elicit digital flexion and test for both intact flexor tendons as well as malrotated fractures.
DONALD BAE
The orthopaedist should assess for the extent of open injuries, which can be subtle in the hand. Radiographs of a bleeding nail bed injury are needed to rule out an open growth plate fracture of the distal phalanx. Neurologic examination can be very difficult in children. One clue to a possible nerve injury is excessive bleeding from a wound around the area of the digital nerve, as the digital artery and nerve are often lacerated together. To stay out of trouble in assessing a nerve, it is helpful to do the “wrinkle test.” Immerse the digit in warm water for about 5
minutes. Denervated digits will not have any wrinkling of the volar skin, and over time, they will have altered sweat patterns (Fig. 8-2).
minutes. Denervated digits will not have any wrinkling of the volar skin, and over time, they will have altered sweat patterns (Fig. 8-2).
THE GURU SAYS…
Anatomy is everything! In the fingers, remember that the digital nerve is dorsal to the digital artery. Therefore, if there is a volar laceration and robust, arterial bleeding from a lacerated digital artery, you should have a high index of suspicion that the nerve is cut too!
DONALD BAE
THE GURU SAYS…
The warm water immersion test is extremely helpful in younger children. Remember, two-point discrimination and other threshold sensory testing can only be reliably done in patients over 5 to 7 years of age.
DONALD BAE
Radiographs of the injured palm and wrist should include an AP, lateral, and oblique views. More complex imaging is rarely needed. Evaluating an injured digit is done best by asking the radiology technician to focus on the finger as opposed to ordering hand films. A true lateral of the injured digit may be very valuable as opposed to a lateral of the hand, often with overlapping fingers that are nondiagnostic.
The treatment of any hand injury begins with proper pain control. Digital blocks are very effective for phalangeal fractures and nail bed injuries. To stay out of trouble, do not use epinephrine for digital block, as it may lead to distal ischemia. Also, never inject a circular weal around the digit as the circulation of the digit can be compromised.
THE GURU SAYS…
Avoid the temptation to accept suboptimal radiographs! Orthogonal views of the affected digit should be obtained when evaluating finger/thumb injuries.
DONALD BAE
Nail Bed Injuries
Nail bed injuries in children are common and can easily be missed. Plain radiographs should be obtained to assess for a concomitant fracture and the germinal matrix can be entrapped in the physeal fracture (the Seymour fracture; Fig. 8-3). The nail should be removed if it is not already off and can be placed in iodine solution for later use. Finger tourniquets can be helpful for visualization and eponychium incisions will allow you to extract the germinal matrix. The wound should be irrigated just like an open fracture. When you repair a nail bed in a child, use loupes and use #6-0 absorbable chromic suture. Stent the nail bed repair with Xeroform or the sterilized nail (if using the nail, put a hole in it to allow drainage).
THE GURU SAYS…
Remember, a Seymour fracture is an open fracture—the wound is just hidden beneath the nail plate. To adequately irrigate and debride the open wound, as well as remove interposed soft tissue to reduce the fracture, you need to remove the nail plate.
DONALD BAE
Distal Phalangeal Injuries
Just like adults, children can jam their finger and suffer a “mallet finger” injury. As opposed to adults (where the extensor tendon is torn), forced flexion of the distal phalanx can result in a Salter Harris I or II injury with the extensor tendon
attached to the epiphysis while the profundus tendon flexes the distal piece. “Jersey finger” injuries usually occur in adolescents near skeletal maturity. The classic example is a football player whose finger gets caught in an opposing player’s jersey, leading to a profundus tendon avulsion.
attached to the epiphysis while the profundus tendon flexes the distal piece. “Jersey finger” injuries usually occur in adolescents near skeletal maturity. The classic example is a football player whose finger gets caught in an opposing player’s jersey, leading to a profundus tendon avulsion.
THE GURU SAYS…
Remember to hold the proximal interphalangeal (PIP) and metacarpophalangeal (MCP) joints extended and isolate distal interphalangeal (DIP) flexion when assessing for flexor digitorum profundus (FDP) integrity.
DONALD BAE
AP, lateral, and oblique radiographs should be obtained to look for avulsion fractures entrapped in the pulley system or in the palm. To stay out of trouble, surgical intervention, within 7 to 10 days after injury, is usually required to reattach the tendon after a jersey finger injury.
THE GURU SAYS…
Kids are amazing! Even more so than in adults, in children distal fingertip amputations healing by secondary intention results in very good aesthetic results with preserved sensation.
DONALD BAE
Distal fingertip amputations and avulsions can be gruesome injuries, brought in by nauseated parents. If the parent brings the amputated part, it is important to assess its quality to decide whether replantation or a composite graft is warranted. When faced with a fingertip amputation you can offer the patient three choices based on the injury: (1) dressing changes for very distal injuries; (2) a composite grafting of the amputated part; or (3) replantation if the amputation is proximal to the DIP joint and the amputated part is in good condition.
THE GURU SAYS…
Remember, for long tubular bones like the phalanges, you can have rotational malalignment without angular deformity or translation. The bones can be twisted without being bent! This can only be identified by careful, systematic physical examination.
DONALD BAE
Fractures of the Proximal and Middle Phalanx
Fractures of the proximal and middle phalanx in children can generally be managed successfully, but do present a few specific sources of trouble. Overall, most proximal and middle phalangeal fractures can be treated with nonoperative management utilizing reduction and casting for 3 to 4 weeks.
One important cause of problems is failure to recognize a rotational deformity (Fig. 8-4). All children should have splints removed, and an examination for rotational malalignment as described above is critical. Phalangeal neck
fractures are small injuries with big problems if not fully appreciated on true lateral radiographs. These fractures need closed reduction and percutaneous pinning. If the articular surface is allowed to heal in a dorsally displaced position, the child will have a permanent loss in flexion. Displaced intra-articular fractures can also lead to joint stiffness if not similarly reduced and pinned. Coronally angulated Salter-Harris (extra octave fracture) proximal phalangeal fractures of the small finger can remodel with growth severe angulated fractures will still require reduction.
fractures are small injuries with big problems if not fully appreciated on true lateral radiographs. These fractures need closed reduction and percutaneous pinning. If the articular surface is allowed to heal in a dorsally displaced position, the child will have a permanent loss in flexion. Displaced intra-articular fractures can also lead to joint stiffness if not similarly reduced and pinned. Coronally angulated Salter-Harris (extra octave fracture) proximal phalangeal fractures of the small finger can remodel with growth severe angulated fractures will still require reduction.
THE GURU SAYS…
For phalangeal neck fractures, try this trick: Take the lateral X-ray and turn it upside down, imagining the PIP joint is the elbow joint and the phalangeal neck fracture similar to a supracondylar humerus fracture. Just like Gartland type II and III supracondylar humerus fractures, displaced phalangeal neck fractures merit closed reduction and pin fixation to preserve joint motion and function.
DONALD BAE
THE GURU SAYS…
Beware the nondisplaced unicondylar fracture of the phalanx. These injuries may be unstable, so careful serial radiographic follow-up is needed, and if there’s any displacement resulting in articular incongruity, go the OR for reduction and fixation!
DONALD BAE
THE GURU SAYS…
The collateral ligaments of the MCP joint are loose in extension and taut in flexion. For closed reduction of proximal phalangeal physeal fractures, flex the MCP joint prior to correcting the angulation to maximize your ability to reduce the fracture. In these specific cases, you have to bend it to straighten it!
DONALD BAE
Finger Dislocations
Although finger dislocations in young children are relatively rare, these injuries are not uncommon in the teenage athlete. To stay out of trouble, look for areas of open injury and do a good prereduction neurovascular examination. If the joint is irreducible, it is possible that there is an interposed ligament or volar plate hindering reduction. Open reduction may be necessary. After an injury to the volar plate, it is important to move the joint early. Do not do extension block splinting because you risk contracture of the child’s PIP joint.
THE GURU SAYS…
Open reduction of irreducible or “complex” MCP dislocations may be performed via dorsal or volar approaches. Consider going dorsal to avoid the volar neurovascular bundles. And in young children, beware of an osteochondral shear fracture that may not have been apparent on the injury radiographs!
DONALD BAE
Fractures of the Metacarpals
In children, the most common site of metacarpal fracture is the neck. Most can be treated with closed reduction and splinting. The physis in the metacarpal is distal, often very near the site of fracture, and remodeling will often correct the residual
deformity in young children. In those that don’t remodel, the malunion in the plane of joint motion is better tolerated than in the coronal plane.
deformity in young children. In those that don’t remodel, the malunion in the plane of joint motion is better tolerated than in the coronal plane.
THE GURU SAYS…
For metacarpal neck fractures, it is challenging to place a well-molded cast in intrinsic-plus position. In children, you can place a cast with the MCP and IP joints extension, allowing for a better mold and hold on the reduction. Just be sure to take the cast off in 4 weeks to avoid long-term stiffness!
DONALD BAE
Metacarpal shaft fractures must be evaluated carefully for malrotation. When the child makes a fist, all fingers should point to the scaphoid and all nail beds should be parallel. Unstable fractures with residual rotational malalignment may require closed reduction and percutaneous pinning. Fractures at the base of the finger metacarpals are infrequent in children. They are usually the result of high-energy trauma. In these cases, a CT scan is valuable. These injuries will often require either closed reduction and percutaneous pinning or open reduction and internal fixation.
Fractures at the base of the thumb metacarpal can present as simple transverse fractures or intra-articular fractures. Salter-Harris type III and IV fractures at the base most closely resemble the adult Bennett fracture. Fractures at the base of the thumb without intra-articular extension can be treated with closed reduction and immobilization. There is great remodeling potential at the base of the thumb because the fracture is juxtaphyseal and the carpal metacarpal joint has universal motion; angulation of up to 20° can be accepted.
THE GURU SAYS…
Higher energy base of metacarpal fractures can be associated with carpometacarpal joint dislocations. Don’t miss the dislocation by focusing only on the fracture! Careful inspection of the lateral hand X-ray is needed to avoid this trap.
DONALD BAE
Ulnar collateral ligament injuries of the thumb (a.k.a., gamekeeper’s thumb) are typically encountered in adolescents rather than young children. Similar to other injuries, the ulnar collateral ligament will be stronger than the adjacent bone, resulting in a Salter-Harris III avulsion fracture rather than ligament disruption. This is a “gamekeeper’s equivalent” and requires open reduction and internal fixation if displaced.
THE GURU SAYS…
There are two compelling reasons to operate on the displaced Salter-Harris III fracture of the thumb proximal phalanx: (1) restoration of articular congruity and (2) restoration of thumb MCP joint stability.
DONALD BAE
Fractures of the Carpal Bones
In general, fractures of the carpal bones in young children are exceedingly rare. The most common is a scaphoid fracture. Be alert to the fact that the scapholunate space may be physiologically wider in an immature child as there is unossified cartilage. This should not be mistaken for a perilunate injury. Comparison views will help define the normal space for the child that presents to you. To stay out of trouble with carpal bone injuries, any patient with pain in the snuffbox should be treated using a thumb spica cast for 10 to 14 days, even if the radiographs are negative. If still tender, MRI is now thought to be the best diagnostic test if there is a question of a scaphoid fracture and X-rays are equivocal. Proximal pole scaphoid fractures are rare but have a high risk of avascular necrosis (AVN). Distal pole fractures seem to heal with no problem. Fractures at the scaphoid waist are similar risks as in adults.
THE GURU SAYS…
Use all the tools in your toolbox! When assessing for a possible scaphoid fracture, check for tenderness in the anatomic snuffbox, tenderness over the scaphoid tubercle, pain with compression between those two points, as well as pain with axial loading of the thumb. Clinical sensitivity is highest when using all these maneuvers.
DONALD BAE
THE GURU SAYS…
Historically, all pediatric scaphoid fractures were thought to be of the distal pole, with universal healing with casting. Times have changed, and children are becoming more like adults. Recent studies suggest fracture patterns in adolescents are similar to those in adults, so beware the scaphoid waist and proximal pole fractures.
DONALD BAE
Fractures of the Forearm
FRACTURES OF THE DISTAL RADIUS AND ULNA
Fractures of the distal radius and ulna are exceedingly common in children. The keys to staying out of trouble include understanding remodeling, avoiding overtreatment, putting your reductions in good casts, and being alert for associated
injuries. Remodeling is greatest in young children, in fractures near a rapidly growing physis, in fractures that are in the plane of motion of the adjacent joint, and in fractures with greater amounts of angulation. Typically, the child can correct about 10° of apex-volar angulation for each year of growth remaining. Radial-ward angulation of the distal radius, caused by the pull of the brachioradialis, corrects more slowly. Bayonet apposition remodels reliably in younger children, especially those younger than about 8 years.
injuries. Remodeling is greatest in young children, in fractures near a rapidly growing physis, in fractures that are in the plane of motion of the adjacent joint, and in fractures with greater amounts of angulation. Typically, the child can correct about 10° of apex-volar angulation for each year of growth remaining. Radial-ward angulation of the distal radius, caused by the pull of the brachioradialis, corrects more slowly. Bayonet apposition remodels reliably in younger children, especially those younger than about 8 years.
THE GURU SAYS…
Sometimes it is hard to know how much more growth a child or adolescent has. One trick is to look at the thumb metacarpal physis, which is usually captured on AP wrist X-rays! If the thumb metacarpal physis is open, the patient has two or more years of growth remaining, and therefore remodeling potential.
DONALD BAE
Physeal Injuries
Physeal injuries of the distal radius are the most common growth plate injury in children. To stay out of trouble, evaluate for open injuries, especially subtle pinpoint openings on the volar skin. Higher energy injuries, such as when a teenager falls rollerblading, can lead to neuropraxia of the median nerve, or even acute carpal tunnel syndrome or compartment syndrome1 (Fig. 8-5). To stay out of trouble, do a careful nerve examination and get these fractures reduced as quickly as is practical. The easiest injury to miss is the second injury, so be certain to evaluate the elbow and hand carefully when confronted with a distal radius fracture (Fig. 8-6).
THE GURU SAYS…
Remodeling is powerful, but remember the radius and ulna don’t spin as they grow longer! Therefore, one cannot expect remodeling of rotational malalignment.
DONALD BAE
Minimally displaced fractures are often placed in a splint and an Ace wrap in the emergency department and sent on to an orthopaedist office for management. NEWSFLASH! There are few things more dangerous than an inexperienced resident with an Ace bandage. A tight Ace wrap can be trouble (Fig. 8-7). Children will shift in the splint, or play with their Ace wrap, which can become rolled and cause a tourniquet-like effect. The Ace wrap can create a row of blisters at the seams between the Ace wrap or create a tremendous amount of swelling distally.
THE GURU SAYS…
It’s especially important to look at the wrist for a possible concomitant scaphoid fracture. Don’t lose the forest for the trees!
DONALD BAE
Displaced fractures can be reduced under conscious sedation at the time of injury. It is a general principle to avoid reductions or rereductions of physeal injuries later than approximately 10 days following injury, in order to avoid growth arrest. Open or closed reduction with Kirschner wire (K-wire) fixation
is used in special circumstances.2 To stay out of trouble with distal radius pinning, care should be taken to avoid the radial sensory nerve and the extensor tendons. Most agree that smooth K-wires across the physis are not a significant risk for growth arrest.3
is used in special circumstances.2 To stay out of trouble with distal radius pinning, care should be taken to avoid the radial sensory nerve and the extensor tendons. Most agree that smooth K-wires across the physis are not a significant risk for growth arrest.3
THE GURU SAYS…
Often one well-placed pin and a cast are sufficient if the reduction is anatomic. You don’t always need to put multiple pins across the physis.
DONALD BAE
Up to 30° to 40° of dorsal angulation at the site of a distal radial physeal fracture will remodel satisfactorily in a child with more than 3 years of growth remaining (Fig. 8-8). Of course, this should not be the goal at the first reduction. However, if an 8-year-old returns to your office with 30° of angulation 10 days later, that can be accepted with an excellent result. The risk of growth arrest from a distal radius physeal fracture is considered to be 4%. However, the rate of growth arrest of a distal ulnar physeal fracture is 60%.4 Stay out of trouble by looking for radiographic growth arrest for a year after any ulnar physeal injury and in any patient whose radial physeal fracture underwent reduction.
THE GURU SAYS…
Physeal fractures that cross the resting zone of the physis (Salter-Harris III and IV fractures) are more challenging. These injuries have a higher growth arrest rate (up to 40%!) and require anatomic reduction to restore articular congruity.
DONALD BAE
Metaphyseal Distal Radius and Ulnar Fractures
To stay out of trouble with these fractures, the clinician has to primarily understand which fractures have to be reduced and what aspects of displacement need to be reduced. As mentioned, a complete bayonet opposed radius fracture does not have to be reduced as long as angulation is acceptable. Putting a child through the pain and risk of a reduction is not justified to make an X-ray look pretty. Conversely, the adept clinician knows that 15° of dorsal angulation in an 8-year-old will remodel, but it won’t in a 14-year-old boy who is skeletally mature and who looks old enough to have a mortgage.
THE GURU SAYS…
Remember the radiographic pearl about the thumb metacarpal physis?
DONALD BAE
Nondisplaced or minimally displaced distal radial metaphyseal fractures can be treated in many ways with a good result. Some orthopaedists use splints and Ace wraps, some use removal Velcro splints, and many cast: in our experience, the least trouble occurs when a well-padded short arm cast is used.
For completely displaced fractures requiring closed reduction, it is important to understand how the thick pediatric periosteum can hurt you and help you. Distal radius fractures in children have tremendous remodeling potential, and this is due in great part to the biologically active periosteum. Mechanically speaking, the intact dorsal periosteum in a volarly angulated fracture can help hold your reduction. However, the periosteum can also hurt your reduction in fractures with bayonet apposition. In this instance, the proximal fragment can buttonhole through the periosteum, making reduction difficult (Fig. 8-9). In bayonet fractures with obliquity, it would be necessary to hyperdistract the fracture to translate the distal fragment volarly; the tough periosteum may make this almost impossible even for the strongest orthopaedic resident. Bayonet apposition in an 8-year-old is fine as long as angulation is minimal.
Dr. Skaggs Adds
One of the few things in pediatric orthopaedics with support from multiple randomized prospective trials is the use of a short arm casts for distal third forearm fractures. I find it curious how many doctors still prefer a long arm cast, despite how much more comfortable a short arm cast is for the patient. It might be different, if it were the doctors wearing the casts.5,6