Although a majority of the tendinous extensions of the forearm musculature traverse the radiocarpal joint, only three muscles insert or originate on the bony surface of this joint. The pronator quadratus and the brachioradialis have a fascial connection and share a common insertion on the distal radius.[15] The brachioradialis, which inserts on the distal radius and radial styloid, serves to flex the elbow, supinate the forearm, and pronate the forearm. It receives motor innervation from the radial nerve. The pronator quadratus, innervated by the anterior interosseous nerve, inserts along the volar surface of the distal radius. It is capable of forearm pronation and is a crucial stabilizer of the distal radioulnar joint.

The scaphoid is the one bone of the radiocarpal joint that serves as a site of origin for the musculature of the forearm and hand. The abductor pollicis brevis, which causes abduction about the first metacarpophalangeal joint originates from the scaphoid tubercle and the trapezium and inserts at the base of the proximal phalanx of the first digit.

The majority of the muscles of both the flexor and extensor compartments of the forearm cross a portion of the radiocarpal joint and affect the motion and stability of the joint.  Some of the osteology of the radiocarpal joint have a profound effect on the function of those muscles. For example, Lister’s tubercle (bony prominence on the dorsal surface of the distal radius), acts as a pulley for the tendon of the extensor pollicis longus.[16] Without this pulley formed by Lister’s tubercle and the EPL tendon, EPL contraction would lead to abduction.

Research has revealed a variable morphology of the radial and ulnar peaks of Lister’s tubercle. In the most common variant, the radial peak is larger than the ulnar peak. The second most common variant has radial and ulnar peaks that are similar heights. The least common variant has an ulnar peak larger than the radial peak. In the least common variance, or type 3 variance, the tendon of the extensor pollicis longus courses on the radial aspect of the tubercle.[16] In the more common variants, the tendon runs within the peaks or on the ulnar aspect of the tubercle. These differences potentially have clinical implications regarding surgical planning and predisposition to wrist pathologies.

The vascular supply of the lunate is a physiologic variant of concern due to the lunate's association with avascular necrosis, known as Kienböck disease. The arterial vessels of the volar surface are the main vascular supply of the lunate. Commonly, there are two to four vessels that traverse the volar carpal ligaments that nourish the lunate. However, there can uncommonly be only one vessel that supplies the volar surface of the lunate.[17]

A fracture of the distal radius among the most common fractures that present to the emergency department or a primary care office in the United States.[18] It is extremely common in the elderly population usually due to a fall onto an outstretched hand. Osteoporotic change to the metaphysis and epiphysis of the distal radius plays a significant role in the frequency of fracture. One study found that the decrease in bone density in the distal radius had a statistically significant correlation to the densities of the hip and vertebra, which are commonly used to evaluate for osteoporosis.[19] The basis for the classification of distal radius fractures is upon fracture pattern and angulation/displacement of the distal fragment.

• Colles fracture: fracture of the distal radius resulting in dorsal angulation
• Chauffeur fracture: avulsion fracture of the radial styloid
• Smith fracture: fracture of the distal radius that leads to increased volar angulation or volar displacement
• Barton fracture: fracture of the distal radius leading to the displacement of the distal fragment and the carpus, resulting in a fracture-subluxation of the wrist.

All of these fractures are treatable surgically. Commonly a volar approach is utilized to reduce a distal radius fracture. After skin incision and dissection through subcutaneous tissue, the interval between the flexor carpi radialis tendon subsheath and the radial artery is opened revealing the pronator quadratus. The pronator quadratus is elevated off of the fracture site, and a volar plate is applied to provide structural fixation to the reduced fracture.[20]

The scaphoid is the most commonly fractured carpal bone, and like distal radius fractures, it is commonly the consequence of a fall onto an outstretched hand. Nonunion is a common complication in this injury due to the delicate vasculature of the scaphoid. However, not all fractures of the scaphoid require surgical attention. Indications for surgical management in a scaphoid fracture include displacement, fracture of the proximal pole, and nonunion.[21] There are multiple surgical approaches for scaphoid fixation, but minimally invasive percutaneous techniques are among the most popular. Kirschner wires are percutaneously driven through the fracture, and a cannulated screw is directed down the wire to provide fixation to the scaphoid.[21]

Falls onto outstretched hands do not only cause damage to osseous structures of the radiocarpal joint, but it can also cause damage to ligamentous structures. The scapholunate interosseous ligament plays a crucial role in wrist stability and injury to this structure can be challenging to diagnose. Patients typically complain of pain and wrist popping or clicking with wrist extension and grip.[22] Instability may be appreciable on radiography displaying the scaphoid in a relative position of palmar flexion and the lunate in a relative position of dorsiflexion.[22] Based on radiographic measurements a diagnosis of dorsal intercalated segmental instability can be made, which requires attention due to the possibility of it advancing to scapholunate advanced collapse (SLAC). SLAC leads to inappropriate dispersion of force across the wrist which can result in accelerated progression of wrist arthritis. Arthroscopy is utilized to provide the surgeon with information on the extent of structural damage so that they may take appropriate surgical steps.

Avascular necrosis of the lunate, also known as Kienböck disease is a condition that occurs due to the disruption of the vasculature to the lunate. While there is no definitive underlying cause for this condition, it is well known what can result if the condition progresses. The collapse of the lunate will lead to proximal migration of the capitate. This altered alignment will result in abnormal scaphoid motion and ultimately arthrosis throughout the radiocarpal joint.[23] However, not all patients who develop Kienböck will progress to widespread wrist dysfunction and osteoarthritis. In the early stages, this condition can be managed conservatively with NSAIDs and rest. Radiographic evidence showing advanced disease requires surgical management ranging from bone graft to wrist fusion.

Buckle fractures are typically found in pediatric patients after a fall onto an outstretched hand. Radiographically it is represented by compression and bulging of the cortex at the distal radius.[24] Children typically have softer more flexible bone compared to adults, explaining why this injury pattern is more common in children. Because this fracture does not typically present with displacement or overt irregularity management is usually non-surgical. Patients are placed in either a short arm cast or a removable splint and are encouraged to avoid activities that could lead to reinjury.[24]

Arthritis is an inflammatory disease of a joint that can be caused by a degenerative change (osteoarthritis) or autoimmune degeneration (rheumatoid arthritis). Degenerative changes in osteoarthritis are the result of repetitive impaction of the wrist leading to the destruction of articular cartilage. This process can be hastened by conditions that alter the dispersion of forces traveling across the wrist. Rheumatoid arthritis is a condition where the body produces an abundance of immune cells and cytokines that target the body's articular cartilage. Both forms of arthritis present with pain in the joints and impaired range of motion. However, osteoarthritis tends to worsen with the increased use of the joint, while rheumatoid arthritis loosens up with increased use.  Additionally, joints affected with rheumatoid arthritis will be warm and swollen. Just as the presentations of these conditions are different, so are their treatments. Osteoarthritis is managed primarily with NSAIDs, rest and if severe enough intra-articular corticosteroid injections. Rheumatoid arthritis has an underlying autoimmune cause. Therefore, treatment aims to reduce the immune response. Pharmacologic agents such as methotrexate are first-line treatment options for this condition. If methotrexate is unable to keep the diseases from progressing biologic agents are an alternative.

Chronic pain of the wrist can range from posttraumatic to degenerative causes for which the non-operative treatments are preferred, but when despite this approach the pain becomes disabling and the function of the wrist is compromised or deteriorated a surgical managed could be considered. Some surgical options include arthroscopic wrist procedures, arthrodesis, denervation. Arthrodesis, which is a fusion of two adjacent bones to immobilize a joint, and resection are considered salvage procedures [25].

An alternative to those salvage procedures is wrist denervation, its concept is not new but the application of this technique has had several modifications and this looks like a promising procedure for palliative care [26]. However, we have to keep in mind that it doesn't improve further degeneration of the joint, and therefore underlying arthritis. More studies are needed to asses the duration of the relief.