The numerous ways and circumstances in which humans can position their hands places the hand and finger joints at risk for injury.
A thorough knowledge of the articular and ligamentous anatomy is paramount to providing the best treatment for each patient.
A good working relationship with the therapist providing care is critical in returning patients back to their vocational and recreational activities with the goal of having a painless and functional extremity.
The activities of daily living require that our hands have stability and motion at numerous joints. The vital usefulness of the hand in so many activities thereby renders it susceptible to trauma, and it is therefore the most commonly injured part of the upper extremity. The incidence of injury peaks during youth and young adulthood due to participation in athletics and industrial vocations. The phalanges and metacarpals account for 10% of all fractures referred to hand surgeons. Soft tissue injuries and dislocations are common injuries as well. The treating physician’s and therapist’s goal is to balance the joint immobilization required for healing with mobilization necessary to prevent stiffness and pain. Swanson stated in his landmark article: “Hand fractures can be complicated by deformity from no treatment, stiffness from overtreatment, and both deformity and stiffness from poor treatment.” The precise balance of proper surgical and therapeutic techniques is critical. Based on a thorough diagnostic evaluation and individualized treatment plan created to address the injuries identified, clinicians may maximize patient recovery and satisfaction and speed return to vocational and recreational activities.
After an injury occurs, a thorough history of the injury should be obtained from the patient, including mechanism, finger position during injury, the presence of deformity, previous treatments received, and a subjective sense of stability. The primary goal of the physical exam is to assess the stability of the injured joint. Observation for symmetrical or asymmetrical edema (consistent with unilateral collateral ligament injury), ecchymosis, and deformity is a critical first step. Palpation should be performed in a standard fashion, utilizing the examiner’s knowledge of the appropriate anatomy to discern patterns of injury.
A radiographic evaluation should be performed prior to assessing range of motion (ROM) and stability in order to exclude obviously unstable or severe injuries. Posteroanterior (PA) and lateral radiographic views of the affected finger are mandatory, and oblique views may be of additional benefit in judging the extent of articular injuries. Occasionally, further imaging using CT or MRI may be required to completely assess intra-articular pathoanatomy. A two-stage functional assessment of the joint should be performed, using a digital or wrist block if motion is limited by pain ( Fig. 32-1 ). It is important to assess the motion of the joint while the patient voluntarily flexes and extends it. The degree of instability and the angle at which the instability occurs should be noted and used to help determine the specific anatomic site of injury. Loss of active motion but full passive motion can be indicative of tendon injury; for instance, an extensor lag may indicate damage to the extensor tendon. Passive manipulation of the joint in flexion and extension as well as lateral deviation should be performed after active motion is assessed. Crepitus during motion and lateral stability should be assessed at full extension and 30 degrees of flexion to determine if the collateral ligaments are injured. The continuity of the volar plate can be assessed via passive hyperextension and dorsal shear stress applied to the joint. Comparison with uninjured digits can be helpful in discerning whether mild instability patterns are physiologic or due to injury.
Proximal Interphalangeal Joint
The proximal interphalangeal (PIP) joint is essentially a ginglymus, or hinge joint, allowing a 110-degree arc of motion although articular asymmetry allows for 9 degrees of supination with full flexion. Anterior/posterior stability is achieved primarily through articular congruity due to the thicker anterior and posterior lips of the middle phalanx. The bicondylar nature of the proximal phalanx, articulating with the biconcave fossae and intermediate ridge of the middle phalanx, provides additional stability against lateral translation. The radial and ulnar collateral ligaments supply lateral angular stability of the joint. The proper collateral ligaments (PCL) are anatomically confluent with the accessory collateral ligaments (ACL), although they are divided by their respective insertions. Both the PCL and ACL originate eccentrically from the dorsal lateral aspect of the proximal phalanx. The PCL traverses volarly and distally and inserts onto the lateral tubercle on the middle phalanx, which lies on the volar aspect of the middle phalanx. The ACL inserts onto the thick, fibrous portions along the lateral aspect of the volar plate (VP), which forms the floor of the PIP joint. Thus the PCL, which attaches more dorsally, is tight in flexion and loose in extension, and the ACL is tight in extension and loose in flexion. The VP attaches along the entire volar lip of the middle phalanx, with thicker attachments at the confluence of the collateral ligaments laterally. The thinner, central portion blends with the periosteum of the middle phalanx, allowing for greater range of flexion. Proximally, the VP tapers centrally and forms cordlike check-rein ligaments laterally, which originate off the periosteum of the proximal phalanx, inside the distal aspect of the second annular pulley (A2) and confluent with the first cruciate pulley (C1). These stout ligaments prevent hyperextension of the PIP joint ( Fig. 32-2 ).
Dynamic stability of the PIP is provided by the extensor and flexor tendons that traverse the joint. The central slip of the extensor tendon attaches to the dorsal lip of the middle phalanx, whereas the flexor digitorum superficialis (FDS) tendon divides proximal to the PIP joint and has separate lateral insertions along the middle phalanx confluent with the A3 pulley. The hand intrinsic muscles combine with the lateral bands of the extensor mechanism to form the conjoined lateral bands, which traverse dorsal to the center of rotation of the PIP joint. The transverse retinacular ligament (TRL) enshrouds the PIP joint and collateral ligaments as it courses from the VP to the conjoined lateral bands, thus preventing dorsal subluxation during extension. The oblique retinacular ligament (ORL) of Landsmeer runs from the flexor tendon sheath proximal to the PIP joint and inserts on the terminal extensor tendon traveling volar to the PIP joint axis of rotation. The course of this ligament effectively couples PIP joint extension with distal interphalangeal (DIP) joint extension and acts as a secondary restraint to PIP hyperextension ( Fig. 32-3 ).
Collateral Ligament Injuries
The wide range of motion of the shoulder and elbow allows for the hands to be placed within a large volume of space. This relative freedom predisposes to hand injury, especially during sports and recreational activities. If enough angular stress is applied to the digits, collateral ligament strain and eventual rupture can occur. Cadaveric studies have shown that the collateral ligament avulses proximally in most injuries, but the VP avulses distally. , In addition, the radial collateral ligament (RCL) is more often injured than the ulnar collateral ligament (UCL).
Collateral ligament injuries are graded based on the pathoanatomy of the injury ( Table 32-1 ). Grade I injuries involve a strain to the ligament with microfibril rupture, but the ligament remains intact. Pain is elicited by direct palpation of the involved collateral ligament, and angular stress testing reveals less than 20 degrees of passive instability. In this injury pattern, the joint is stable throughout active range of motion (AROM) and passive range of motion (PROM) testing, and can be managed nonoperatively with a brief period of positioning with an orthosis for pain control, followed by AROM within a week of injury. Buddy-taping or strapping the digit adjacent to the injured digit allows for ROM activities and passive protection of the joint.
|Grade I||Grade II||Grade III|
|Pathology||Sprains/diffuse fiber disruption||Complete disruption of one CL||Complete disruption of one CL as well as volar and/or dorsal structures|
|Functional ROM testing|
|Treatment||Immobilize, slight flexion 3–10 days, and buddy-taping||Immobilize 3–4 weeks, may begin early protected motion||Closed treatment if stable after reduction versus early open treatment|
Grade II injuries involve a complete rupture or tear of the ligament without instability of the joint during AROM. These injuries may be associated with a small avulsion fracture of the base of the middle phalanx. Stress testing that notes passive instability involving greater than 20 degrees of angular deviation is indicative of a grade II tear, as long as frank dislocation is not identified. These injuries require more aggressive treatment with 2 to 4 weeks of gutter splinting; however, early motion can be initiated if angular stress can be avoided via buddy-straps or under the supervision of a therapist.
Grade III injuries imply complete collateral ligament rupture combined with VP or dorsal capsular rupture. Instability during AROM testing as well as with PROM testing occurs in both lateral and either dorsal or volar stress. Dislocation with either spontaneous or manipulative reduction is likely to be noted with these injuries. Nonoperative treatment requires concentric reduction to be obtained and maintained during ROM activities. Blocking orthoses can be used to prevent subluxation and dislocation by preventing motion in ranges where instability is present. If concentric reduction cannot be maintained, operative treatment is necessary.
Dislocations of the middle phalanx dorsally on the proximal phalanx represent 85% of dislocations at the PIP joint. These injuries are the result of hyperextension stress applied to the joint with some element of longitudinal compression directly leading to varying degrees of bony injury. In pure PIP dislocations the VP is commonly ruptured distally; however, on rare occasions it can rupture proximally and, along with the check-rein ligaments, become interposed, thereby preventing attempts at closed reduction. , The dissipation of energy through the PIP joint during hyperextension follows a predictable pattern and is subdivided into three groups, proposed by Eaton and Littler. The initial hyperextension results in rupture or avulsion of the thin central portion of the VP along with longitudinal tears in between the fibers of the ACL and PCL. However, the thick, lateral portions of the VP—the so-called critical corner—remain intact. The initial injury to the joint can result in locked hyperextension that must be manually reduced. As the energy increases, the critical corners are injured, and the middle phalanx dislocates dorsally, often held colinearly to the proximal phalanx via intact fibers of the PCL, which are split from the ACL, which additionally remains intact. These type II injuries manifest as a pure dorsal dislocation in which the volar lip of the middle phalanx is perched on the condyles of the proximal phalanx and they may be associated with a small avulsion fracture of the base of the middle phalanx. Type III injuries involve simultaneous collateral ligament injury and some degree of lateral instability, but often manifest as dorsal dislocations ( Fig. 32-4 ).
Most dislocations can be treated with closed reduction under digital block followed by an assessment of stability during AROM and PROM. If the joint remains stable up to 25 degrees short of full extension, positioning in an extension block orthosis can be initiated, such as with a figure-of-8 orthosis. These orthoses allow for active flexion of the PIP joint, while preventing subluxation at increasing degrees of extension ( Fig. 32-5 ). Dislocations with small avulsion fractures of the base of the middle phalanx can be treated as though they represent pure dislocations. The splints are eliminated at 3 weeks, and ROM exercises are continued. Reductions that remain unstable or are stable in greater than 25 degrees of flexion, require operative stabilization with volar plate arthroplasty (VPA), extension block pinning, and dynamic external fixation. Irreducible dislocations require open reduction, which can be accomplished via a limited dorsal approach, using a Freer elevator to reduce the interposed soft tissue. A volar approach requires a larger incision in order to mobilize the flexor tendons around the joint, but does allow for concomitant repair of injured volar structures or VPA.
The most common complications from dorsal dislocations are residual instability due to inadequate treatment and flexion contracture. A mild flexion contracture is common and has been termed a pseudoboutonnière deformity ; however, it is not a true boutonnière deformity since the DIP joint remains flexible and the central tendon remains attached to the dorsal lip of the middle phalanx. Operative treatment can introduce infection risks from pin tracts and increase soft tissue scarring, which leads to increased stiffness.
In comparison with dorsal dislocations, volar dislocations are rare but more problematic because they frequently involve an avulsion of the central slip at its dorsal attachment. Concomitant unilateral collateral ligament injury can lead to rotatory subluxation of the middle phalanx as it rotates around the intact collateral ligament tether. The difference between these two entities must be elucidated clinically since the treatment algorithm is different. Pure volar dislocations occur with a longitudinal and volar force applied to a semiflexed PIP joint, whereas rotational torque on the joint can lead to rotatory instability. As the joint dislocates volarly, the dorsal capsule tears, allowing the head of the proximal phalanx to herniate in between the lateral band and central tendon. These two structures can form a “noose” around the condyles of the proximal phalanx, preventing reduction via longitudinal traction, which tightens the noose. Reduction can be performed with wrist extension and metacarpophalangeal (MCP) flexion, to loosen the extrinsic and intrinsic extensors, respectively, followed by middle phalanx flexion and dorsal pressure. If closed reduction is unsuccessful after several attempts, open reduction should be performed.
Following reduction, the central slip should be manually tested to assess if avulsion has occurred. If the central tendon is intact, and no subluxation occurs during AROM testing, early ROM exercises can be initiated to prevent stiffness. However, if central tendon injury occurs, positioning the PIP joint in full extension in a gutter orthosis must be performed for 6 weeks to allow for healing. Active DIP motion should be initiated immediately, and this joint should not be immobilized in the orthosis. Operative treatment is indicated for residual instability following reduction and includes pinning and collateral ligament repair for rotatory instability.
Fractures involving the distal and proximal articular surfaces of the PIP joint are fairly common, but result from different stresses placed on the joint. Condylar fractures of the proximal phalanx occur with simultaneous lateral and compressive forces, whereas fractures of the middle phalanx occur with compressive and flexion–extension forces. Varying degrees of longitudinal stress applied to the joint can lead to increasing amounts of comminution in the fractures. Fractures about the PIP joint are prone to develop stiffness; thus the goal of treatment is to maximize the stability of the fractures with minimal soft tissue trauma so that active motion can begin quickly.
Volar shearing fractures commonly occur as dorsal fracture–dislocations of the PIP joint. The extent of injury is graded by the amount of articular surface involved, which is directly related to the inherent stability of the fracture. Fractures involving less than 30% of the articular surface are stable and can be treated with extension block positioning and early mobilization. Fractures involving 30% to 50% of the volar articular surface are variably stable and depend on the extent of collateral ligament injury. Fracture fragments larger than 40% of the articular surface generally encompass most of the PCL, rendering the middle phalanx unstable to closed treatment. Fractures with greater than 50% articular surface injury have little collateral ligament stability and have lost the cup-shaped articular surface that provides intrinsic stability to the joint. Nondisplaced fractures and stable displaced fracture patterns are treated with a protective orthosis of the PIP joint while allowing for active MCP and DIP motion. Careful, close follow-up is mandatory to ensure that fracture displacement or joint subluxation does not occur during healing. Orthosis use can be discontinued and AROM/PROM initiated once fracture healing is identified, although protected AROM exercises supervised by a therapist can be considered after 2 to 3 weeks with stable patterns. An orthosis should not be used on fractures for longer than 30 days, nor positioned in greater than 30 degrees of flexion, as flexion contractures are likely to develop.
Unstable fracture patterns require open treatment, and in recent years, numerous techniques have been added to the hand surgeon’s arsenal. Simple large fracture fragments are ideal for open reduction and internal fixation (ORIF) with lag screws or Kirschner’s wires (K-wires) ( Fig. 32-6 ) . This can be performed through a volar approach using Brunner’s incisions and opening the flexor sheath between the A2 and A4 pulleys. The most important aspect of surgical correction is restoration of the volar lip of the middle phalanx, which provides most of the stability that prevents recurrent dorsal subluxation. However, comminution is frequent and can be underestimated on radiographs. If such comminution is encountered, the fracture fragments can be excised and the fibrocartilaginous VP advanced to fill the defect. This VPA can be attached with suture anchors or through pull-out sutures or narrow-gauge wire placed around the extensor mechanism ( Fig. 32-7 ). This procedure should not be attempted when greater than 50% of articular comminution is present because the significant advancement may lead to flexion contracture and the pliable surface of the VP can allow for dorsal subluxation.
For comminuted fractures involving greater than 50% of the articular surface, a relatively new technique known as hemihamate arthroplasty has been shown to be extremely effective ( Fig. 32-8 ). With this procedure, the dorsal lip of the distal articular surface of the hamate, which closely approximates the biconcave fossae of the proximal aspect of the middle phalanx, is harvested and placed in the defect so as to recreate the volar lip and provide stability against dorsal subluxation. This procedure can restore most PIP motion, even when reconstruction is delayed; however, lengthy delays can lead to decreased motion, and most patients have at least a small residual flexion contracture due to the extensive soft tissue mobilization required. Persistent dorsal wrist pain and carpometacarpal (CMC) joint instability have not been reported with this procedure.
Another option for large, comminuted volar lip fractures is dynamic external fixation ( Fig. 32-9 ) . Numerous methods have been described; however, the underlying principle is the same; fractures are reduced through traction via ligamentotaxis, and the subluxation is reduced and maintained with the appropriate placement of the external fixation pins. These devices allow for AROM to be initiated immediately within the constraints of the system; however, pin tract infections (≤25%) frequently occur. Typically, these do not result in long-term sequelae if treated appropriately with oral antimicrobials. Additionally, closely monitored radiographic follow-up is required to ensure maintenance of the reduction.
Fractures of the dorsal lip of the middle phalanx involve an avulsion injury of the central tendon and must be approximated to prevent late boutonnière deformity. Fracture fragments that are reduced within 2 mm of anatomic alignment with an extension orthosis can be treated with full-time immobilization that allows for DIP motion. Failure to reapproximate the central slip of the extensor tendon can lead to imbalance at the PIP and DIP joints, resulting in a boutonnière deformity (flexion contracture of the PIP joint and fixed hyperextension of the DIP joint). Active flexion can be initiated after fracture healing occurs, generally within 4 weeks of the injury. Simple displaced fractures can be treated with pinning or open reduction. Extension block pinning may be performed; however, it is important to place the pins obliquely between the central slip and the lateral bands to prevent scarring, thereby limiting PIP and DIP motion.
Dynamic external fixation is additionally the treatment of choice for patients with comminuted, depressed pilon fractures involving the entire articular surface. These fractures are generally not amenable to open treatment with interfragmentary fixation. Dynamic fixation reduces subluxation and can realign the dorsal and volar fragments although longitudinal traction cannot reduce the depressed articular surface. Interfragmentary pins can be placed to reapproximate markedly displaced fragments, and articular remodeling can occur, leading to a stable joint. However, post-traumatic arthritis and loss of motion are common due to the extensive damage sustained in the initial injury. The use of immediate joint arthroplasty or arthrodesis has been reported sporadically in the literature. Arthrodesis is generally not recommended in the ulnar digits, though it is a useful tool for the index PIP joint, as key pinch (the predominant use of the index digit) is performed in PIP flexion and requires absolute stability of the PIP joint.
Longitudinal, angular force can result in fractures of the condyles of the proximal phalanx and are especially common in athletes. Because these fractures do not involve joint subluxation and ROM can be preserved, they are often misdiagnosed as sprains and patients do not seek treatment until late deformity or persistent pain develop. These fractures can be classified into three categories based on severity. Type I fractures are stable, nondisplaced, unicondylar fractures; type II injuries are unstable, displaced unicondylar; and type III are bicondylar or highly comminuted fractures. Nondisplaced unicondylar fractures can be treated with orthotic positioning and close radiographic follow-up, as displacement is common despite adequate treatment. Unstable fractures require stabilization with either percutaneous pinning or ORIF using screws or a minicondylar plate via a midlateral approach. A percutaneous tenaculum clamp can aid in fracture reduction, and provisional fixation allows for anatomic alignment, even in type III injuries. Dynamic external fixation can play a role in markedly comminuted fractures where fixation cannot be achieved with pins or screws. Provided the articular surface remains aligned, outcomes are generally good, and patients may continue to improve postoperative motion for more than 1 year after surgery due to articular remodeling.