Hand and Wrist Surgery - part 6 ppsx

F R A C T U R E S A N D D I S L O C A T I O N S O F T H E H A N D 282 PEARLS • While the patient is under digital block at the time of reduction, assess the integrity of the central slip insertion by resistance to PIP flexion with the MP joint flexed. • Begin motion as early as patient comfort will allow. • Assure a concentric reduction: incarceration of the collateral ligaments within the joint will preclude their healing at an appropriate length. PITFALLS • Boutonniere deformity • Stiffness • Laxity 46 Lateral Dislocations of the Proximal Interphalangeal Joint Christopher H. Martin and Steven Z. Glickel His tory and Clin ical Presentation A 43-year-old man caught his left small finger in the coat button of a coworker and the digit was forcefully deviated ulnarward. He felt a snap, and noticed an angular deformity through the proximal interphalangeal (PIP) joint and an inability to fully extend the finger. Dia gno stic Studies Radiographic evaluation in the emergency room showed a lateral dislocation of the proximal interphalangeal joint (Fig. 46–1). Initial clinical examination showed sen- sory function to be intact on both sides of the digit, with brisk capillary refill. A digital block was placed and the dislocation was reduced with gentle longitudinal traction. Radiographic examination confirmed a concentric reduction of the PIP joint with a symmetric joint space. Phy sic al Examination While still anesthetized, the finger was examined to assess stability of the joint and integrity of the extensor system. The patient was able to actively move the digit through a full range of motion. There was no subluxation noted. The integrity of the extensor mechanism and central slip insertion was then tested by having the patient extend the PIP joint against examiner resistance with the metacarpophalangeal (MP) joint flexed. There was full extension with normal strength compared with the uninjured digit. The digit was splinted with the PIP joint in full extension. The patient was seen weekly for the next 2 weeks with radiographs confirming maintenance of the reduction. After 2 weeks, the digit was buddy taped to the adjacent ring finger and range of motion was begun. Due to some mild laxity in the healing radial collateral ligament, the digit was buddy taped for a total of 4 weeks, after which a full, painless range of motion had been achieved. Dif feren tia l Di agn osi s Volar PIP rotary dislocation Lateral PIP dislocation PIP joint fracture dislocation PIP joint sprain L A T E R A L D I S L O C A T I O N S O F T H E P R O X I M A L I N T E R P H A L A N G E A L J O I N T 283 Figure 46–1. Posteroanterior (PA) radiograph of the small finger shows a lateral dislocation of the proximal interphalangeal (PIP) joint. The proximal and middle phalanges are both in the same plane, suggesting that there is not a major rotatory component to the dislocation. Radiographic examination of the laterally dislocated proximal interphalangeal joint is sufficient to diagnose this injury. Depending on the plane of the radiograph, however, confusion between the true lateral dislocation and the volar rotatory dislocation is relatively common. This distinction is important because the extensor mechanism is disrupted in the volar rotatory dislocation as the head of the proximal phalanx protrudes through the triangular ligament between the lateral band and central slip. The rotatory component of the volar dislocation can be suggested on plain x-rays if one view of the digit shows a true lateral of the proximal phalanx with an oblique radiograph of the middle phalanx (Fig. 46–2). This can help the practitioner to distinguish between these injuries. In the straight lateral dislocation, the extensor mechanism may or may not be injured. Figure 46–2. Lateral and oblique radiographs of the injured digit show an incongruous PIP joint. The proximal and middle phalanges are in nearly the same plane in the radiograph on the left, suggesting that this is a simple lateral dislocation. F R A C T U R E S A N D D I S L O C A T I O N S O F T H E H A N D 284 Dia gno sis Lateral Dislocation of the PIP Joint Lateral dislocations usually result from laterally directed or torsional forces acting on an extended proximal interphalangeal joint. The radial collateral ligament is injured six times more frequently than the ulnar collateral ligament. True lateral dislocations of the PIP joint are relatively rare when compared with dorsal and volar rotatory dislocations. However, the patient himself or an athletic trainer prior to presentation probably reduces some of these dislocations, like the more common dorsal dislocation. The clinician must be wary of any significant injury to the PIP joint, as stiffness, pain, and limited use may supervene even with appropriate treatment. These symptoms may continue to improve after the injury, so education of the easily frus- trated patient is particularly important to optimize the result of treatment. Nonsurgical Management The concept of the “box” formed about the head of the proximal phalanx by the volar plate and the accessory and true collateral ligaments of the PIP joint is useful when considering the pathoanatomy of dislocations of this joint. Lateral dislocations may occur after injury to the volar plate and at least one collateral ligament. Both collateral ligaments may also be ruptured. Biomechanical studies of the constraints about the PIP joint have demonstrated that the collateral ligaments may fail at any point along their course, including an avulsion fracture from the phalanges. The location of ligament failure is dependent on the rate at which the lateral stress is applied. Failure of the proximal portion of the ligament is most common. After reduction and while under digital block anes- thesia, the degree of injury to the collateral ligaments may be assessed by the extent to which the joint opens upon the application of lateral stress. Opening over 20 degrees is associated with a 100% chance of complete failure of the collateral ligament, whereas opening less than 20 degrees is associated with only a 53% chance of complete rupture. Although this information is not useful in cases of documented dislocation, it may become useful in those instances in which the patient reports an injury to the PIP joint that he or she has self-reduced. An intact lateral band will extend the PIP joint, and may mask an injury to the central slip. Therefore, it is important to isolate the central slip when testing for injuries to the extensor mechanism to whatever extent possible. Flexion of the MP joint places the lateral bands at a mechanical disadvantage, allowing preferential as- sessment of the integrity of the central tendon insertion. Missed injuries of the central slip insertion may result in a boutonniere deformity, which is potentially one of the major pitfalls in the management of injuries to the PIP joint. Due to the bony architecture of the PIP joint, concentric reduction usually pro- vides sufficient stability to allow for early motion within the limits of reasonable comfort. The arc through which the joint is stable should be assessed at the time of injury to avoid subluxation or redislocation. This is best done when the joint is anesthetized, preferably with a digital block. Those factors that need to be considered in selecting the optimal position of joint immobilization include the volar plate, the collateral ligaments, and the extensor mechanism. In lateral dislocations the volar plate is generally avulsed from the base of the middle phalanx, so splinting in 20 to 30 degrees of flexion would seem L A T E R A L D I S L O C A T I O N S O F T H E P R O X I M A L I N T E R P H A L A N G E A L J O I N T 285 prudent to avoid laxity and subsequent hyperextension. Minamikawa et al have demonstrated that the intact PIP joint is most resistant to lateral stress in full extension. This implies that the collateral ligaments are most taut in full extension. Im- mobili zation in sl ight flexio n, therefore, wo uld allow the liga ments to begin healin g in a slightly shorter position, possi bly avoiding the development of laxity. However, if injury to the ex tensor mechanism is suspected, the joint should be splint ed in full extension to avoid the complication of a boutonniere deformity. Regardless of the position of immobilization, motion should be instituted as early as possible. The common complication of injuries to the PIP joint is stiffness, not laxity. Volar plate and collateral ligament injuries can be mobilized as soon as the patient is comfortable, providing the joint is stable. Central tendon injuries should be protected longer, for about 3 weeks, and then mobilized, protecting the extensor mechanism with a dynamic extension splint. Surgical Management Repair of the injured collateral ligaments and volar plate in the acute setting does not improve the outcome and may result in increased stiffness of the joint. Acute surgical intervention is reserved for cases of incongruent reductions, generally from tissue interposed within the joint. Stern has described a Stener-type lesion after lateral dislocation of the PIP joint in which the collateral ligament was incarcerated between the lateral band and the central slip, necessitating operative intervention. Although this lesion would seem more likely in volar rotatory dislocations, in which the triangular ligament between the lateral band and central slip is ruptured, it may be seen in true lateral dislocations. Complications Stiffness is a much more common sequela of injuries to the PIP joint than symptomatic joint laxity. The surgical management of stiffness has included everything from percutaneous release of the accessory collateral ligament to open complete excision of the collateral ligaments. Motion should be instituted as early as possible to avoid joint stiffness. Laxity of the PIP joint is rare but can be very difficult to manage if it occurs. The re- sults of collateral ligament reconstruction are unpredictable and may have the less than desirable effect of exchanging the problem of laxity for that of stiffness. Excision of both ligaments in the lax joint, followed by early motion, may restore stability as each ligament is allowed to reform in a more balanced situation. Suggested Readings Bowers WH. The proximal interphalangeal volar plate I: an anatomical and biomechanical study. J Hand Surg [Am] 1980;5A:79–88. Diao E, Eaton RG. Total collateral ligament excision for contractures of the proximal interphalangeal joint. J Hand Surg [Am] 1993;18A:393–402. Eaton RG. Joint Injuries of the Hand. Springfield, IL: Charles C. Thomas; 1971. F R A C T U R E S A N D D I S L O C A T I O N S O F T H E H A N D 286 Kiefhaber TR, Stern PJ, Grood ES. Lateral stability of the proximal interphalangeal joint. J Hand Surg [Am] 1986;11A:661–669. Minamikawa Y, Horii E, Amadio PC, Cooney WP, Linscheid RL, An K-N. Stability and constraint of the proximal interphalangeal joint. J Hand Surg [Am] 1993;18A: 198–204. Rhee RY, Reading G, Wray RC. A biomechanical study of the collateral ligaments of the proximal interphalangeal joint. J Hand Surg [Am] 1992;17A:157–163. Stanley JK, Jones WA, Lynch MC. Percutaneous accessory collateral ligament release in the treatment of proximal interphalangeal joint flexion contracture. J Hand Surg [Br] 1986;11B:360–363. Stern PJ. Stener lesion after lateral dislocation of the proximal interphalangeal joint- indication for open reduction. J Hand Surg [Am] 1981;6A:602–604. 47 Dorsal Dislocations of the Proximal Interphalangeal Joint Rosa L. Dell’Oca and Amy Ladd History and Clinical Presentation A 40-year-old right hand dominant mechanic presented with a painfully swollen incongruent proximal interphalangeal (PIP) joint of his right index finger after a tire exploded while he was increasing the air pressure. Closed reduction, although successful, resulted in an unstable joint. Physical Examination The PIP joint demonstrated 15 degrees of ulnar deviation with considerable edema and a volar laceration. Tenderness was elicited over the volar and radial aspects of the joint. Pain limited full active flexion, and the middle phalanx subluxed dorsally at 10 degrees of active extension. Diagnostic Imaging Anteroposterior, lateral, and oblique radiographs of the involved digit were obtained (Fig. 47–1). D O R S A L D I S L O C A T I O N S O F T H E P R O X I M A L I N T E R P H A L A N G E A L J O I N T 287 A B Figure 47–1. Right index finger prereduction anteroposterior (A), oblique (B), and lateral (C) views, and postreduction lateral view (D). (Continued) F R A C T U R E S A N D D I S L O C A T I O N S O F T H E H A N D 288 Differential Diagnosis Dorsal dislocation of the PIP joint Lateral dislocation of the PIP joint Volar dislocation of the PIP joint Fracture of the distal proximal phalanx Fracture of the proximal middle phalanx Sprain of the PIP joint Lateral dislocation: greater than 20 degrees of angulation with ulnar/radial stress of the PIP joint; radial or ulnar joint tenderness with or without volar plate tenderness; anteroposterior (AP) radiograph may demonstrate lateral displacement. Volar/lateral dislocation: lateral radiograph exhibits middle and distal phalanges at an oblique angle as compared with the proximal phalanx. Volar dislocation: tenderness of the dorsal aspect of the base middle phalanx; lateral radiograph reveals a fracture of the dorsal aspect of the base of the middle phalanx. Fractures: AP, lateral, and oblique (condyles) radiographs may display fractures of the head of the proximal phalanx or the base of the middle phalanx. Diagnosis Dorsal Proximal Interphalangeal Joint Dislocation Dorsal PIP dislocations are probably common but underreported, because many high-paid athletes play with fresh injuries set in the field, or present with old un- treated injuries that may be painful, unstable, or fused. Estimated at 9/100,000/year, the incidence of dorsal PIP fracture dislocations is much higher. History, physical examination, and radiographs reveal the diagnosis and prog- nosis, and facilitate treatment. History divulges the mechanism of injury and sug- gests the final configuration of the joint despite memory lapse or spontaneous or deliberate reduction. The joint may assume the characteristic bayonet configuration or an obvious posture of hyperextension but occasionally subtle subluxation requires radiographic elucidation. Palpation delineates the injured structures and active range of motion may reveal instability with progressive extension. Although pain and edema typically limit flexion, a torn volar plate interposed within the C D Figure 47–1. Continued The full extent of the injury is appreciated best on lateral exam (C) and only after reduction (D), where the 50% involvement of the articular surface and the severely comminuted fragments may be appreciated. PEARLS • Obtaining perfect lateral radiographs to detect the subtlest incongruity • Obtaining prompt attention by hand specialist, or knowledge- able practitioner and to not ignore this common injury PITFALL • Disregarding the injury as a simple sprain without adequate physical and radiographic examination D O R S A L D I S L O C A T I O N S O F T H E P R O X I M A L I N T E R P H A L A N G E A L J O I N T 289 joint must be considered. If radiographic evaluation displays joint congruity, then subtle instability may be elucidated by passive range of motion facilitated by a digital block. Stability on physical exam reflects the extent of injury to the primary (volar plate collateral ligament complex) and the secondary (flexor and extensor system) stabilizing forces, where certain sizes and configurations of fractures of the volar base of the middle phalanx compromise these forces. Their vulnerability to hyperextension or longitudinal loading defines their order and characteristic of injury. A simple sprain, recognized by a moderate amount of tenderness over the bruised but stable joint with a normal radiograph represents a partially torn ligament. Despite the check rein ligaments, proximal detachment of the volar plate occurs ex- perimentally with slow hyperextensile forces. Conversely, longitudinal accelerated hyperextensile forces cause distal rupture of the transversely oriented fibrocartilaginous fibers of the volar plate. This injury alone allows greater than the normal 10 degrees of hyperextension. Typically, in these hyperextension injuries there is no history of abnormal joint position, no evidence of instability on active and passive range of motion, and no articular incongruity or fracture on radiographs. Even with an incom- plete longitudinal split in the collateral ligament, the remaining intact accessory collateral ligament imparts some stability. Higher energy forces produce tears between the thin accessory collateral ligament and the thick primary collateral ligament in addition to volar plate disruptions. Ex- periments suggest that partial volar plate tears represent areas of potential weakness at risk of rupture with repeated stress. Typically, these injuries present with a history of joint misalignment and radiographs may demonstrate a small volar fragment. Part of the weak volar central trabecular base of the middle phalanx may remain at- tached to the volar plate, otherwise known as an avulsion injury. Larger volar fragments typically result from greater longitudinal rather than hyperextensile forces, where the proximal phalanx shears off the volar base of the middle phalanx. Smaller volar fragments (<30–50%) retain support from the remaining accessory collateral ligaments and a portion of the primary collateral ligament (Eaton and Dray’s “stable dislocations”), whereas larger fragments portend relying solely on the extensor tendon and dorsal capsule for stability in flexion and have no support in extension, which explains the propensity to redislocate after reduction (Eaton and Dray’s “unstable dislocations”). A direct correlation exists between the percent of volar middle phalanx surface fractured and the likelihood of dorsal subluxation/dislocation. Maximum contact between the articular surfaces of this ginglymus joint, and the action of the flexor and extensor tendons pulling axially through a column consisting of the middle phalangeal base, resting on the proximal phalangeal condyles stabilized by the inter- digitation of the intercondylar sulcus and eminence, resist dislocation even in the face of collateral ligament and volar plate disruption. With intraarticular fractures, the residual middle phalangeal dorsal articular surface and shaft form an inclined plane that tends to slide dorsally and proximally as the extensor and flexor tendons pull the distal portion of the middle phalanx volarly and the proximal end of the middle phalanx dorsally, creating a zigzag posture. Furthermore, the slightly different radii of curvature of the condyles allow some rotation despite the inherent lateral stability, which explains disproportionate injury to radial versus ulnar collateral ligaments. Classification systems with varying emphasis on the degree of ligamentous integrity, the percentage of articular involvement, or the degree of subluxation exist to facilitate the correct treatment. The history of injury, the point and degree of instability, and radiographic evaluation are adequate determinants in our opinion. F R A C T U R E S A N D D I S L O C A T I O N S O F T H E H A N D 290 Treatment The injured athlete often reduces the dislocated finger. If not, usually gentle traction will suffice to reduce the subluxated PIP joint. Reduction of a true dislocation requires reproduction of the original angle of injury to realign the joint surfaces and traction on the middle phalanx with volarly directed pressure at its base. Regional blocks, muscle relaxants, finger-trap traction and arm-loaded countertraction facilitate the difficult reductions, unless there is a hindering soft tissue entrapment. The ease of reduction is proportional to the quantity of intact ligament and in- versely proportional to the size of the fragment. Fragments greater than 40% of the base herald instability. Joint congruity takes precedence over anatomic reduction of the fracture, for the subtlest incongruities may lead to chronic pain, degenerative changes, and ankylosis. The goal is stable, smooth, and pain-free range of motion of the affected joint. This may be surprisingly difficult to attain. Nonoperative Management After reduction or placement of the PIP joint at an acceptable angle without evidence of subluxation, a period of rest is followed by protected active range of motion. For simple sprains, 1 to 3 weeks of splinting followed by a protected return to normal activities within a few weeks with buddy taping, suffices. An extension block splinting (EBS) regimen succeeds for hyperextension injuries, yet some might buddy tape for 3 weeks or implement dorsal splinting for 7 to 14 days with an additional 2 weeks for residual volar instability followed by active and passive range of motion. Similar injuries, with radiographic evidence of minor subluxation that achieves congruity with manipulation fall into the same category but require hypervigilance with weekly radiographic confirmation of joint congruity for several weeks, followed by active and passive range of motion in a splint worn for an additional 1 to 2 weeks. A known dislocation, demonstrating instability at less than 30 degrees of flexion with or without a nondisplaced intraarticular fracture involving less than 50% of the volar lip, may be treated successfully by closed reduction and EBS for 3 weeks, with active range of motion commencing at 7 days followed by 3 weeks of buddy taping. Operative Intervention Dislocations involving large volar fractures or those irreducible, unstable, or incongruous joints, regardless of fracture size, require operative intervention. In large disruptions of the middle phalanx volar surface, without the stabilizing collateral ligaments, the proximal phalangeal condyles sink into the volar plate and the distal inserting flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) bend the middle phalanx rather than produce gliding palmar rotation of the articular base. The joint fails to remain congruent and parallel with the proximal phalangeal head through flexion. As a result, the joint hinges or angles. For these tenuous fractures, a transarticular Kirschner wire (K wire) may be placed through the PIP joint flexed at 40 degrees or more to diminish the subtle fracture articular site incongruities associated with eventual failure and EBS initiated after K-wire removal at 3 weeks. Failure of closed reduction leaves open intervention or constant traction as subsequent options. Open reduction with internal fixation and EBS mobilization at 3 weeks have been successful for tenuous fractures using such means as a single . interphalangeal joint. J Hand Surg [Am] 19 86; 11A :66 1 66 9. Minamikawa Y, Horii E, Amadio PC, Cooney WP, Linscheid RL, An K-N. Stability and constraint of the proximal interphalangeal joint. J Hand Surg [Am]. contracture. J Hand Surg [Br] 19 86; 11B: 360 – 363 . Stern PJ. Stener lesion after lateral dislocation of the proximal interphalangeal joint- indication for open reduction. J Hand Surg [Am] 1981;6A :60 2 60 4. 47 Dorsal. interphalangeal joint: A review of ten years’ experience. J Hand Surg [Am] 1980;5: 260 – 268 . Green SM, Posner MA. Irreducible dorsal dislocations of the proximal interphalangeal joint. J Hand