Home Sports Injuries KARL-ANTHONY TOWNS: WRIST FRACTURE AND ORTHOPEDIC SUB-SPECIALTIES

KARL-ANTHONY TOWNS: WRIST FRACTURE AND ORTHOPEDIC SUB-SPECIALTIES

by Gary Vitti
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My introduction to Sports Medicine and Orthopedics began with the academic year 1979/80 as I entered graduate school at the University of Utah. At that time the team physician was responsible for all musculoskeletal issues from the foot on up to the shoulder with the exception of the spine. The spine has always been its own sub-specialty in orthopedics. With the exception of the spine, the same orthopedic doctor treated you whether you had a knee issue or a hand issue. It was a one-stop-shop for patients and why not since orthopedic surgeons go through a comprehensive educational, training and certification process. When you see your orthopedic doctor and you receive the invoice, this is what you are paying for: four years of undergrad, followed by four years of medical school, followed by five years of residency training, followed by a one-year sub-specialty and for some an additional one-year fellowship in Sports Medicine.

Orthopedics eventually became a practice of specialties beyond the spine that were generally sub-divided into foot/ankle, knee/shoulder, hand/wrist/elbow or hip. In today’s blog we’ll address my experience with two wrist injuries, wrist fracture and wrist sprain. The wrist is a complicated part of the body with more issues than I will address here but in my 40 years of experience, these are the injuries I commonly saw from falling on an outstretched hand to break one’s fall.

Most recently in the NBA, it has been reported that Karl Anthony-Townes has a fractured wrist. I have no direct knowledge of Karl’s injury or even what bone he fractured but I will discuss several wrist injuries starting with a fracture.

The wrist is composed of eight small bones (carpal bones) and the two long bones of the forearm — the radius (thumb side) and the ulna (pinkie side). The carpal bones are arranged in two rows at the base of the hand with four bones in each row. The most common injured wrist bone is the scaphoid navicular at the base of the thumb just above the radius. The name scaphoid navicular like its counterpart in the foot (tarsal navicular) get its name from the Greek term for a boat. They both resemble a boat because of their long, curved shape. The scaphoid navicular can most often be identified and palpated in the “hitchhiking” position. With the thumb in the up position, a hollow will be formed between two tendons. The hollow is referred to as the “anatomical snuff box”. The snuff box is the site of tenderness or pain when a scaphoid navicular fracture occurs.

Scaphoid navicular fractures can often be mistaken for a wrist sprain. Sometimes initial x-rays will not show the fracture. After several weeks additional x-rays may show healing which is an indication there was a fracture. MRI and CT scan are more revealing for fracture and can also help in determining whether the bones are displaced or not. A non-displaced fracture means the bone fragments line up correctly. A displaced fracture means the bones have moved out of place to form a gap between the bones or the bones overlap one another.

Treatment depends on the location of the fracture, whether it is displaced or not or how long ago the fracture occurred. Fractures that occur towards the thumb end of the bone can heal within weeks with immobilization. If the fracture is displaced its probable that surgery would be required to stabilize the bone fragments to heal properly. A fracture in the middle of the bone referred to as the waist of the bone will also require surgery because of the poor blood supply in that area. Surgery usually requires a screw, wire and/or bone graft. Bone stimulators are also used to try and speed up healing time.

Complications include a non-union which means the bone did not heal. In the event of a non-union, a bone graft is usually recommended. Because of the poor blood supply to the waist of the scaphoid navicular, there is a possibility of avascular necrosis. A condition in which the bone dies. In this case, the most effective treatment is a vascularized bone graft. There are different types of bone grafts and bone graft substitutes depending on fracture classification and surgical technique.

Early and correct diagnosis is integral for a good long term result. Poor diagnosis and poor treatment will result in both non-union and avascular necrosis leading to arthritis and chronic wrist pain.

Wrist sprains like scaphoid navicular fractures are most often sustained by falling on an outstretched hand to break one’s fall. They are classified as mild, moderate and severe as I’ve explained in other blogs about soft tissue injuries. Today I will discuss the severe wrist sprain know as the scapholunate disassociation.

The scapholunate disassociation is also known as the rotary subluxation of the scaphoid. This injury causes an abnormal position of the scaphoid navicular carpal bone next to the lunate carpal bone. It is sustained from the tearing of the scapholunate interosseous ligament which provides stability between the two carpal bones. Interruption of the scapholunate ligament is the most commonly injured carpal ligament. It presents with minimal swelling but significant pain over the top of the wrist which increases with dorsiflexion (bending the wrist towards the head).

Initial diagnosis of the injury can be difficult, as it often takes 3 to 12 months before dynamic instability is detected on plain x-rays. X-rays are typically taken with a clenched fist and the hand turned towards the pinkie side (ulnar deviation) to identify if there is a widening of the medial-lateral gap between the carpal bones. A negative MRI is unable to rule out a clinically relevant injury. There are also physical exam tests in which the practitioner will try to elicit a shift or clunk of the scaphoid navicular in relation to the other carpal bones.

The consequences of an untreated scapholunate disassociation are significant. The most common pattern of degenerative arthritis in the wrist is a scapholunate advanced collapse resulting in pain swelling and loss of function.

The last wrist sprain I would like to discuss is the triangular fibrocartilage complex (TFCC). It is an area between the two main bones of the forearm (radius & ulna) that articulate with the carpal bones to form the wrist. The TFCC is made up of ligaments, tendons and cartilage. The TFCC is a wrist injury that is also sustained by falling on an outstretched hand to break a fall. The TFCC keeps the radius and ulna stable when the hand grasps or the forearm rotates. Symptoms of a TFCC are pain at the base of the pinkie side of the wrist which worsens when the wrist is bent from side to side.

A TFCC is diagnosed by a physical exam and MRI. Most of the time they will improve with immobilization. In a few cases, surgery is required and can take up to 3 months to heal completely. In summary, although a TFCC can be painful and affect one’s ability to use their hand or wrist they generally get better on their own without surgical treatment.

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