A. Phalangeal Fractures and Dislocations
Proximal and Middle Phalanx Fractures –
Transverse proximal phalanx fractures tend to angulate apex volar due to the pull of the lateral bands proximally and the central slip distally. These fractures may be closed reduced and treated with the MCP joint flexed to 90 degrees and the PIP joint in extension. Residual angulation or rotational deformity should be treated with percutaneous pinning.
Oblique proximal phalanx fractures tend to be rotationally unstable and frequently require pinning or ORIF with minifragment lag screws.
Middle phalanx shaft fractures tend to be unstable and frequently require pinning or ORIF. Fractures of the base of the middle phalanx are considered unstable if greater than 40% of the joint surface is involved, requiring pinning or ORIF. Otherwise these fractures may be treated with extension block splinting for 4-6 weeks.
Displaced intraarticular fractures require ORIF with anatomic joint reduction.
Distal Phalanx fractures –
Extensor tendon avulsion injury to the distal phalanx (mallet finger) not associated with volar subluxation of the DIP joint may be treated with strict splinting in extension for six weeks.
Dorsal or volar base fractures that involve greater than 25% of the joint surface may be associated with subluxation of the DIP joint and require ORIF (volar) or percutaneous pinning (dorsal). Shaft fractures are frequently difficult to splint, and benefit from percutaneous pinning.
Ulnar Collateral Ligament Injuries to the Thumb –
Injuries to the ulnar collateral ligament of the MP joint of the thumb is caused by forced radial deviation of the thumb. This injury is typically called a gameskeeper’s thumb or skier’s thumb, referring to a radial force applied to the first web space by a gun or ski pole. The thumb will demonstrate instability when examined in extension and 30 degrees of flexion. With complete rupture of the UCL, the adductor aponeurosis may become interposed between the torn ends of the UCL , requiring open repair of the ulnar collateral ligament. This is known as a Stener lesion.
B. Metacarpal Fractures
Metacarpal fractures are frequently caused by a direct blow to the metacarpal head (clenched fist resulting in intrarcticular head fractures or neck fractures), dorsum of the hand (resulting in transverse shaft fractures), or twisting of the fingers (spiral oblique shaft fractures). Physical examination should include examination for open wounds (fight bites require aggressive I&D and exploration of the extensor tendon), rotational malalignment in flexion and extension, and complete neurovascular exam (compartment syndrome of the hand common in crush injuries). AP, lateral, and oblique radiographs may be supplemented by the Brewerton view (MP joint flexed 65 degrees, dorsum of fingers lying on plate with tube angled 15 degrees ulnar to radial) for fracture detection.
Closed treatment of metacarpal shaft fractures is indicated for single fractures with less than 10 degrees apex dorsal angulation (may accept greater angulation in the fourth and fifth metacarpals, 20 degrees in the thumb), less than 3-4mm shortening, and no rotational deformity. Closed treatment consists of 3-4 weeks of casting with the wrist in 45 degrees of extension, the MCP joints flexed fully, and the IP joints free. Surgical treatment is indicated for displaced intraarticular or collateral avulsion fractures, unstable shaft fractures, or comminuted fractures, and may include percutaneous pinning, ORIF, or mini-external fixation.
Fractures of the base of the carpometacarpal joint of the thumb may be extraarticular (rare), partial articular (Bennett’s fracture), or complete articular (Rolando’s fracture). These fractures typically require closed reduction and percutaneous pinning or ORIF.
C. Carpal Fractures and Dislocations
The eight carpal bones in the wrist are commonly divided into two rows. The proximal row is composed of the scaphoid, lunate, triquetrum, and pisiform. The distal row contains the trapezium, trapezoid, capetate, and hamate. A complex of ligaments runs between the bones of the carpus and the distal radius and play an important role in the stability of the wrist.
The blood supply to the carpus is fed by three palmar and three dorsal vascular arches, which are in turn fed by the radial, ulnar, and the anterior and posterior interosseous arteries. The vascular supply is especially relevant in the scaphoid, lunate, and capitate, where large areas of bone are supplied by a single interosseous vessel, making the bones succeptible to avascular necosis (AVN) following fracture.
Carpal factures may occur with a force on a hyperextended hand or direct blow to the carpus. This frequently occurs with a fall on an outstretched hand, but may occur with sports, MVAs, or industrial accident. The position of the hand and the direction of the force determines the exact injury; for example, hyperextension and radial deviation causes scaphoid fractures. Pain with palpation of the injured carpal bone may reveal fracture. Pain in the anatomic snuff box is sensitive (but not specific) for scaphoid fracture.
PA, lateral and oblique radiographs of the wrist should be obtained. The PA radiograph should be evaluated for smooth arches formed by the proximal carpal row and the midcarpal joint. The clear space between the carpal bones should be equal, and widening of this clear space to greater than 3mm suggests ligament injury (especially in the scapholunate interval, the Terry Thomas sign). The lateral radiograph should be evaluated for a collinear relationship between the radius, lunate, capitate and metacarpals. The long axis of the scaphoid should be 30-60 degrees from this axis. CT, MRI, and bone scan may be helpful in diagnosing occult fractures of the wrist.
Treatment of fractures and dislocations of the carpus is aimed at reestablishing normal anatomic relationships and stability of the wrist. Immobilization for extended periods of time may be required for treatment of non-displaced fractures. Closed reduction of displaced or dislocated segments is attempted; open reduction may be required. Percutaneous pinning of unstable segments may be required to reestablish ligamentous stability. Excision of small fragments may be indicated in certain situations.
Scaphoid Fractures –
Scaphoid fractures are classified according to the location of the fracture (proximal pole, waist, distal-third body, and tuberosity) and the degree of instability (fracture pattern, displacement, and communition). The blood supply to the proximal scaphoid is from a single artery off of the radial artery, entering the scaphoid at the waist and supplying the proximal scaphoid in a retrograde manner. Thus, displaced fractures at or proximal to the scaphoid waist are succeptible to AVN of the proximal fragment. If non-displaced, fractures may be hard to visualize, and delayed images, CT, MRI and bone scan may be helpful in diagnosis. Non-displaced fractures may be treated in a thumb-spica cast, while displaced fractures require ORIF with K-wire or compression screw (Herbert or Acutrak screws) fixation and possibly bone grafting
D. Distal Radius Fractures
Fractures of the distal radius are among the most common fractures, occurring most frequently as an osteoporotic fracture in elderly females. The mechanism of injury is frequently a fall onto an outstretched hand, although several mechanisms may result in several distinct fracture patterns.
The distal radius is primarily cancellous bone with thin cortices. The distal radius has two major articulations: the radiocarpal joint and the distal radioulnar joint (DRUJ). The radiocarpal articulation is bi-concave and articulates with the proximal carpal row, with two fossae separated by a dorsal-volar ridge for articulation with the scaphoid and lunate. The triangular fibrocartilage complex (TFCC) stabilizes the DRUJ and transfers approximately 20% of the axial load seen by the wrist to the ulna.
Patients with distal radius fractures will present with pain, decreased range of motion, and often with the classic “silver fork” or “dinner fork” dorsal deformity of the wrist. Pain with flexion and extension of the fingers may be present, and numbness in the median nerve distribution may be present if the carpal tunnel is compromised by malalignment or swelling. Radiographic evaluation should include AP, lateral and oblique views of the wrist. Evaluation of the radiographs should include description of the fracture and any articular involvement or ulnar styloid fracture, as well as evaluation of the radial inclination (approximately 20 degrees), radial styloid height (12mm), and volar tilt (12 degrees). Evaluation of the proximal carpal row should evaluate for scapholunate ligament injury, carpal instability, and scaphoid fracture.
Several eponyms exist for distal radius fractures. A Colles’ fracture is a dorsally angulated extraarticular fracture, commonly seen after a fall on an outstretched hand. A Smith’s fracture is an extraarticular fracture with volar angulation. A volar or dorsal Barton’s fracture is an intraarticular lip fracture with volar or dorsal displacement of the carpals. A Chauffeur’s fracture is an ulnar styloid fracture, frequently an avulsion injury associated with scapholunate ligament injury. A Melone four-part fracture is a lunate impaction injury associated with a die-punch depressed articular fragment.
Treatment of distal radius fractures begins with an attempted closed reduction using a Bier block or hematoma block. If post-reduction radiographs show that the fracture is in acceptable alignment, with maintenance of radial height, volar tilt, and anatomic reduction of the articular surface, then the fracture can be treated closed, initially in an above-elbow splint in full supination followed by a below-elbow cast for 4-6 weeks. Frequent radiographs should be taken to ensure that the fracture does not re-displace.
Operative treatment is indicated if the fracture cannot be reduced adequately or held with cast immobilization. Closed reduction and percutaneous pinning may be employed to hold reduction in extrarcticular fractures, but does not allow reduction of the articular surface. External fixation, either on the same side of the joint or joint-spanning, may be employed to hold length and reduction in comminuted extraarticular fractures. Open reduction and internal fixation either through a volar approach, dorsal approach, or both allows reduction of the joint surface. Carpal tunnel release may be indicated at the time of operative treatment of the fracture if the patient is symptomatic.