Last Updated on May 18, 2024
Wrist arthrodesis or wrist fusion is a salvage procedure where the wrist is immobilized by fusing the radius and carpal bones. It aims to provide a pain-free immobile wrist in a maximum functional position.
The wrist arthrodesis procedure is used in advanced wrist arthritis, after complex wrist fractures wrist fractures, or severe ligament injuries. It can be done as an additional procedure with tendon transfers and deformity correction of the wrist. The wrist arthrodesis can be total or of selected bones like four-corner arthrodesis.
However, wrist arthrodesis, though it can provide a painless wrist, limits the function of the wrist, and may impact daily work or occupation. Hence, it should be salvage procedure when nothing else will work. Also, the limitations of the procedure should be discussed with the patient. A plaster cast in the desired position for a few weeks may simulate the effect of the procedure on daily routine and help the patient in making a decision.
Wrist arthrodesis can be total or subtotal depending on the number of bones fused.
Relevant Anatomy
The wrist joint is formed by
- Distal radioulnar joint
- Radiocarpal joint
- Intercarpal joints.
The distal radioulnar joint is formed by the ulnar notch at the distal radius and ulnar head. It is a type of pivot joint that is in tandem with the proximal radio-ulnar joint leading to pronation and supination of the forearm. An important surgical landmark is the Lister’s tubercle. It is a bony prominence on the distal radius and can be palpated on the dorsal aspect. It serves as a pulley for the extensor pollicis longus tendon.
The radiocarpal joint is an ellipsoid joint formed by the distal end of the radius and the scaphoid and lunate fo the proximal row of carpal bones. The carpal bones on the ulnar side make only limited contact with the ulna and that too in the ulnar deviation of the wrist. The capsule of the radiocarpal joint, ligaments including the radio-carpal ligament and collateral ligaments play an important role in stabilization.
The intercarpal joint is in between various carpal bones. There are eight carpal bones organized in 2 carpal rows. The proximal row contains the scaphoid, lunate, triquetrum, and pisiform from the lateral to the medial side. The distal row contains the trapezium, trapezoid, capitate, and hamate from lateral to medial. The distal carpal bones articulate with the metacarpal bones.
Many intercarpal ligaments, flexor tendons that pass through the carpal tunnel, 6 extensor compartments on the dorsal aspect provide the additional stability.
Radius is the main load-bearing bone. It bears about 80% of the load whereas the ulna bears only 20.
The following motion occurs at the wrist joint
- Flexion- 40% by the radiocarpal joint and 60% by the mid-carpal joint
- Extension – 65% radiocarpal joint and 35% mid-carpal joint.
- Radial deviation- almost entirely (90%) by the mid-carpal joint
- Ulnar deviation- Both radiocarpal and midcarpal contribute equally
- Pronation-supination includes both upper and lower radioulnar joint
Indications Wrist Arthrodesis
Pain and instability of the wrist is the most common reason for the wrist arthrodesis. These can result from the following causes.
- Wrist arthropathy not responding to conservative treatment
- Trauma
- Rheumatoid arthritis
- Crystalline arthropathy
- Carpal instability
- Tumors
- Septic arthritis
- Mechanical overuse
- Scaphoid nonunion
- Degenerative osteoarthritis
- For stabilization of the wrist when combined with tendon transfers
- Salvage of unsuccessful wrist arthroplasty
- Previous, unsuccessful, more limited arthrodesis
- Reconstruction of the wrist in
- Segmental tumor resection or large bone defect
- Infection
- Traumatic bone loss of the distal radius and carpus
- Neurological conditions
- Brachial plexus paralysis
- Cerebral palsy
- Spastic hemiplegia
- Failed four-corner fusion
- Failed proximal row carpectomy
- Kienbock’s disease
Contraindications of Wrist Arthrodesis
- Open distal radial physis
- Elderly patient with a sedentary lifestyle (Consider arthroplasty, relative contraindication only)
- Sensory deprivation of hand
Preoperative Workup and Preparation
The surgery aims to provide a stable joint in an acceptable functional position. Therefore the position would depend on the requirements of the patient.
Usually, the wrist is placed in slight dorsiflexion and ulnar deviation to optimize power grip but in bilateral cases, one hand is placed in 5 -10 degrees of flexion to facilitate perineal care.
The patient should be examined for the presence of carpal tunnel syndrome, distal radioulnar joint arthritis, or ulnocarpal impaction syndrome because these can remain symptomatic even after arthrodesis.
Imaging is done to evaluate the wrist radiologically. AP, later, and oblique x-rays of the wrist are done and examined to note the arthritic changes present. Joints that are to be spared from fusion should be especially noted. These are –
- The distal radioulnar joint
- Carpometacarpal joint other than the third one
- Ulnar variance [comparison to opposite side can be made]
- Competence of the intercarpal ligaments by clenching the fist
CT can be done in cases where X-rays do not fully help in evaluation.
Total wrist arthrodesis is the standard procedure that involves the fusion of the following bones
- Radioscaphoid
- Radiolunate
- Scaphocapitate
- Capitate-lunate
- Capito-trapezoid
- Third carpometacarpal joint
Kienbock disease or avascular can be treated with limited arthrodesis that fuses the radial aspect of the carpus.
A scaphotrapeziotrapezoidal arthrodesis can be considered for scapholunate dissociation resulting from the rupture of the scapholunate ligament as it takes off the load central column of the wrist.
In the case of radioscaphoid arthritis, then a scaphoid excision and a four-corner involving lunate,-triquetrum-capitate-hamate) arthrodesis is necessary and can be planned.
The patient is advised to quit smoking in advance as smoking may jeopardize the success of the fusion.
Procedure of Wrist Arthrodesis
Taking all the standard sterile precautions, a longitudinal incision is made on the dorsal aspect of the wrist between the third and fourth extensor compartments. The sensory branches of the superficial radial nerve lies immediately radial to the incision and should be protected.
The dorsal wrist capsule and extensor retinaculum are opened and the extensor pollicis longus tendon is elevated radially. The Lister tubercle is removed. The tendon of the third compartment is retracted radially, and the tendons of the fourth compartment are retracted ulnarly.
A cancellous bone graft can be obtained from the distal radius just radial to the Lister tubercle.
After opening the dorsal intercarpal ligaments, the articular surfaces that are to be fused are decorticated. A bone graft is placed between the decorticated bone ends. Some contouring of the bones may be required for better plate seating.
The 3.5 compression plate is sized and applied to provide at least six cortices of fixation at the third metacarpal and distal radius.
In total wrist arthrodesis, the following joints need to be fused
- Radioscaphoid
- Radiolunate
- Scaphocapitate
- Capitate-lunate
- Capitate-trapezoid
- Third carpometacarpal (CMC)
Lunotriquetral, capitate-hamate, and triquetrum-hamate [ulnar-sided joints] are fixed if there is significant arthritis in these joints at the time of operation. Arthritis of the distal radioulnar joint if recognized, can be managed by resection of the distal ulna and extensor carpi ulnaris tenodesis.
A lag screw through the radioscaphoid joint can help prevent ulnar deviation and ulnar impaction syndrome. The dorsal capsule and extensor retinaculum are closed, and then the overlying skin is closed.
Postoperatively early finger mobilization is advised, and patients are usually not allowed to weight bear through the affected arm for 8 to 12 weeks following the surgery.
Complications
Most of the complications are minor. The reported complications in different studies are up to 20%.
Following are the reported complications of the wrist arthrodesis
- Hematoma
- Injury to vessels or nerve
- Infections
- Tendon injuries and tendon adhesions
- Extensor pollicis longus is the most commonly injured tendon
- Plate tenderness
- Pseudarthrosis- A failure of fusion resulting in a false joint
- Fracture of healed fusion.
- Carpal tunnel syndrome
- Graft donor site complications
- Implant issues
- Reflex sympathetic dystrophy
- Poor wound Healing
- Persistent unexplained pain
Outcome
Wrist arthrodesis provides good pain relief and correction of the deformity. Patients can perform most of the activities of daily living. The problem is experienced in negotiating hand in tight spaces.
Though plating leads to satisfactory fusion rates in elbow arthrodesis, plate-related complications are a concern. Other methods of fixation are carpometacarpal joint sparing implant intramedullary device and arthroscopic techniques.
The outcome may be influenced by the causation as well. In the case of rheumatoid arthritis patients, which is often the most common indication reported, there is an increased risk of repeat surgery and a higher complication rate.
In arthritis of the wrist due to injury, the pain relief may not be as predictable as desired.
