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RATIONALE FOR TOTAL WRIST FUSIOn
Full (or total) wrist fusion (arthrodesis) sacrifices all flexion/extension and radial/ulnar deviation at the wrist to eliminate pain and/or provide stability or both. The procedure is irreversible. Although the loss of these movements produces a certain limitation in function, the effects of reduction of pain and/or instability cannot be underestimated.
INDICATIONS
After its first description in 1910, total wrist fusion initially gained popularity as a treatment for infection—especially tuberculosis—before being more widely used in treating conditions such as rheumatoid arthritis, and awkward contractures caused by poliomyelitis, obstetric palsy, and Volkmann’s ischemia. Early techniques involved sliding corticocancellous bone grafts, some supplemented by a variety of fixation methods. Contemporary indications are very different and usually relate to the management of degenerative conditions—primary, inflammatory, or post-traumatic.
In all cases, however, a total wrist fusion is performed to relieve pain or to improve stability or positioning. The procedure is appropriate for patients of any age.
Primary Osteoarthritis
Advanced primary degenerative disease irreversibly damages the articulating surface, often leading to painful movement regardless of the range of motion. Indeed, even when the joint is so stiff that only a narrow arc of movement remains, pain can still be intolerable and uncontrolled by splintage and analgesia. Sleep pattern can be affected as well as the simplest daily activities of dressing, feeding, and personal care. In these circumstances, a total wrist fusion should be considered. Bone stock is likely to be adequate, skin quality is likely to be good, and patients are usually well motivated ( Fig. 39-1 A–D).
Secondary Osteoarthritis
People with secondary osteoarthritis make up one of the two largest groups of candidates for total wrist fusion. Arthritic changes following persistent scaphoid nonunion advanced collapse (SNAC) ( Fig. 39-2 A–D) or scapholunate advanced collapse (SLAC) are the most common causes in a general wrist practice in the Western world. These conditions are often undiagnosed at the time of injury and may present for the first time some years later owing to the symptoms from subsequent degenerative changes. Treatment for the primary condition is not indicated when degenerative changes are established.
Arthritic changes after severe articular fractures of the distal radius might be expected to produce more candidates for total wrist fusion, but these patients rarely require fusion. Such fractures are common and are not universally treated with accurate reduction and fixation; yet they do not always produce the stiff and painful degenerate joint one would predict.
Other causes of secondary arthritis, such as Kienböck’s disease and septic arthritis ( Fig. 39-3 A–D), also produce candidates for total wrist fusion.
Inflammatory Arthropathy
Inflammatory arthropathies may cause significant symptoms in the early stages before the radiologic features of advanced degeneration have developed. It is important to resist the temptation to provide a permanent surgical solution at this early stage because many of these unpleasant clinical symptoms resolve or abate with time and/or appropriate medical management.
These inflammatory conditions are grouped as seropositive (e.g., rheumatoid arthritis) or seronegative (e.g., gout, psoriatic arthropathy, and chondrocalcinosis). The pathologic process resulting in joint surface destruction is fundamentally different from primary or post-traumatic osteoarthritis, but the resultant clinical complaints of pain and stiffness are often very similar.
Rheumatoid arthritis patients form one of the two largest groups of candidates for total wrist fusion. Fusion is usually possible with less rigorous stabilization than that required for secondary arthritis, since patients with rheumatoid arthritis are prone to spontaneous ankylosis as a feature of their underlying condition.
Conversely, in other inflammatory arthropathies—particularly psoriatic arthropathy—it can be extremely difficult to achieve a mature fusion. Affected patients often have a dense, sclerotic subchondral bone structure that makes union difficult to achieve in spite of the excellent surgical stabilization that can be obtained.
Tumor
In rare cases, bone tumors in the distal radius (e.g., a giant cell tumor) and carpus demand radical resection. Total wrist fusion, usually with substantial quantities of bone graft (often vascularized in the form of a free fibular transfer), may be the only reasonable option.
Neurologic Conditions
Certain neurologic conditions that result in spasticity (e.g., cerebral palsy, cerebrovascular accident, obstetric brachial plexus palsy) cause deformity in joints. In its early stages, this spastic deformity can be managed by splintage, manipulative therapy, and/or botulinum injection. However, when the deformity is no longer passively correctible, further nonoperative therapy is fruitless. If the resultant joint contracture leaves the joint in a functional position, further treatment is unnecessary. Usually, however, the spasticity is such that the stronger muscles overcome the weaker antigravity muscles, and a tight, extreme fixed flexion contracture results. Digital function is poor if the wrist sits in this position. Correction of the deformity and fusion in a more functional position can greatly enhance global digital and upper limb function.
Complex Reconstruction
In some combinations of neural injuries, a significant loss of specific muscle group function ensues. In the more severe cases, restoration of function using tendon transfers may be limited by a paucity of remaining innervated musculature. Wrist motors such as the extensor carpi radialis brevis and longus (ECRB and ECRL) can be used as donors to reanimate crucial digital functions, in which case a total wrist fusion stabilizes the unstable wrist—now deprived of its motors. However, if this technique is considered, care must be taken not to carry out a wrist fusion in combination with those tendon transfers that produce their action through a wrist tenodesis effect. In these cases, removing the additional wrist excursion leads to a failure of the transfer.
The Ideal Candidate
An individual clinical decision based on pain and/or instability is made for each patient. There is no x-ray that shows wrist instability so severe that it is deemed that the wrist must be fused. It is obligatory to give each patient sufficient information and time to reach the best decision for his or her lifestyle. It is often helpful for a patient who is considering total wrist fusion to use a rigid splint for a number of weeks. This reversible fusion simulates both the pain relief and the functional limitations provided by the surgery.
In the rare instances in which fusion is being considered in a child, trial pinning of the wrist has been recommended as a means of allowing the younger patient to understand the likely effects of surgery.
The ideal candidate for total wrist fusion would display the characteristics listed in Box 39-1 .
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Minimal range of flexion/extension motion
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Unremitting pain no longer controlled by analgesia
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Sleep disturbance
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Positive response to rigid splintage
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Unaffected distal radioulnar joint
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Mobile, pain-free fingers
The aims of treatment for rheumatoid patients are usually different from those suffering from post-traumatic arthritis. Patients with rheumatoid arthritis usually require treatment to maintain independence in necessary daily tasks, whereas post-traumatic patients often expect a level of function that is akin to their preinjury status. It is critical to ensure that all patients understand the irreversible nature and likely outcome of wrist fusion before surgery is arranged.
There is evidence that the functional outcome is significantly better when fusion is performed for a specific local cause (e.g., Kienböck’s disease) rather than for widespread arthrosis.
CONTRAINDICATIONS
There are few absolute contraindications to total wrist fusion.
Active or suspected infection should be aggressively treated when wrist fusion is planned. Attempted surgery before control of infection is likely to result in an infected nonunion and bone loss. This makes further attempts at surgical stabilization more difficult.
Poor dorsal skin quality (e.g., as a result of steroid medication, burn contracture, or scarring) increases the risk of wound dehiscence, especially if plate fixation is chosen.
Skeletally immature patients with juvenile rheumatoid arthritis occasionally require consideration for wrist fusion. Great care should be taken to limit the damage to the physis at the time of surgery, either by delaying surgery and managing the wrist pain with wrist splints until skeletal maturity or by avoiding spanning the growth plate with any implants. Fusion is usually rapid in this age group.
Osteopenia remains a relative contraindication because of the difficulty in securing bony stability with an implant. Multiple Kirschner (K) wires may be the best option in these circumstances, although the new generation of angularly stable locked implants provides improved stability.
If the patient is selected for bilateral fusion, thought must be given to the position of fusion in both dominant and nondominant wrists so that independence is not threatened and all regular activities can still be performed.
SURGICAL TECHNIQUE
A number of techniques have been described, including fusion with simple bone graft, fixation with intramedullary Rush or Steinmann pins, multiple K wires, staples, and internal fixation with generic or specifically designed titanium plates. Standard-sized plates are now available for use in a standard case in which no previous procedures have been performed. Shorter plates are available for patients in whom a previous proximal row carpectomy has been performed.
Planning
The patient should receive a full clinical examination (with particular emphasis on assessment of skin quality) and an explanation of the procedure immediately before surgery. Carpal tunnel syndrome should be ruled out. The irreversible nature of total wrist fusion demands that the surgeon revisit his or her decision critically just before surgery.
The limb should be clearly marked with an indelible skin marker.
General or regional anesthesia is required. The patient’s arm is prepared and draped to the level of the upper arm tourniquet. The surgeon should sit cranially to best visualize the dorsal surface of the wrist.
Prophylactic intravenous antibiotics are recommended at induction of anesthesia.
Incision and Approach
A dorsal midline incision is made centered on the middle metacarpal. Care is taken to avoid the small superficial sensory nerve branches. Dissection is carried through the third extensor compartment, raising the second and fourth extensor compartments subperiosteally to reveal the dorsal surface of the distal radius ( Fig. 39-4 ).
Related posts:
Ulnar Head and Styloid Fractures
Traumatic Extensor Carpi Ulnaris Disruption: Subluxation, Dislocation, Rupture
Management of Soft Tissue Contractures Around the Distal Radioulnar Joint
External Fixation of Distal Radius Fractures
Arthroscopic Trapeziometacarpal Arthroplasty
Bone Tumors of the Hand and Wrist
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