Mallet Finger: don’t try this at home

There are a few everyday life experiences that everybody is destined to go through every now and then. Like correctly plugging a USB device only at the third attempt (despite there are only two possibilities), or directly setting the alarm clock half an hour earlier because we know we’re used to putting it off at least four times, or having Mallet Finger.

Mallet Finger is probably one of the most painful and annoying injuries of all time. Technically, it is an injury of the extensor digitorum tendon of the fingers at the distal interphalangeal joint (DIP). In more simple terms, it is the typical injury that occurs when we play basketball and the ball suddenly hits our extended finger. Besides the immediate sensation of pain, within a few minutes our finger will start swelling and we won’t be able to straighten it for a while. We then leave the court with an awesome facial expression (it really hurts, you all know…), but do we know what happened inside our finger?

mallet finger The distal interphalangeal joint (DIP) hinge jointof the hand is nothing more than a hinge joint between the two last phalanges of the finger. This kind of joint only admits one degree of freedom, which is the rotation about the joint axis. As a result, our phalanges are allowed to make flexion and extension movements. Thus, the DIP is the last joint of the finger. A sudden high force acting at the tip of the finger (the ball we were trying to catch) strongly solicits the thin DIP extensor tendon. In case of rupture, or tearing, of this tendon from the bone, the finger usually gets painful, swollen, and bruised. Occasionally, blood can collect beneath the nail. In the worst case, the force of the blow may even pull away a piece of bone along with the tendon. mallet finger bruised The loss of extensor tendon continuity might lead to severe consequences and must be carefully treated. In a first moment, ice should be immediately applied and the hand should be elevated above the level of the heart. Medical attention should be sought within a week after injury. Most mallet finger injuries can be treated without surgery. fingertip splintsNormally, X-rays are necessary in order to look for potential bone fractures or joint misalignment. The presence of blood beneath the nail and nail detachment may be a sign of nail bed laceration or open (compound) fracture. A splint can be applied to hold the fingertip straight (in extension) until it heals (8 weeks full-time, 3-4 further weeks less frequently). With this treatment plan, the finger usually regains an acceptable function and appearance. Despite that, it is not guaranteed that the patient will be able to regain full fingertip extension.

If nonsurgical treatment fails, after mallet finger surgeryconsultation with an orthopaedic surgeon the patient may consider to resort to surgical repair. In case of very severe deformity or inability to properly use the injured finger, surgery is done to repair the fracture using pins, pins and wire, or even small screws. Surgical treatment of the damaged tendon can include tightening the stretched tendon tissue, using tendon grafts, or even fusing the joint straight.

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sources: mainly this website and this website, and then Google Images

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the Knee Bursae: some hints

The bursae of the knee can be defined in a very simple way: they are fluid sacs, or synovial pockets. This second definition comes from the sinovial fluid that fills them.

Synovial fluid is made of hyaluronic acid and lubricin, proteinases and collagenases. Its main functions are reducing friction by lubricating the joint, absorbing shocks and properly “feeding” joint cartilage. In the case of the knee, the Knee Capsule encloses the Knee Cavity which is filled with synovial fluid. Knee Bursae surround and sometimes communicate with the Knee Cavity, as we can see in the picture.

Usually Knee Bursae are thin-walled and represent the weak point of the joint. At the same time, their presence is really important since they enlarge the joint space. They can be grouped according to:

  • their characterization as communicating and non-communicating bursae. A communicating bursa is when a bursa is located adjacent to a joint, thus having the synovial membrane in communication with the joint itself.
  • their location (frontal, lateral, medial).

In pathological conditions, such as excessive local friction, infection, arthritides or direct trauma, fluid and debris collect within the bursa or fluid extends into the bursa from the adjacent joint. As a consequence, the walls of the bursa thicken as the bursal inflammation becomes longstanding. The term bursitis refers to pathological enlargement of the bursa. Clinically, bursitis mimics several peripheral joint and muscle abnormalities.

   

<–prepatellar bursitis

          elbow bursitis–>

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sources: Wikipedia and this website

the Meniscus: some hints

Medically speaking, the “cartilage” is actually known as the meniscus. The meniscus is a C-shaped piece of fibrocartilage which is located at the peripheral aspect of the joint. The majority of the meniscus has no blood supply. For that reason, when damaged, the meniscus is unable to undergo the normal healing process that occurs in most of the rest of the body. In addition, with age, the meniscus begins to deteriorate, often developing degenerative tears. Typically, when the meniscus is damaged, the torn piece begins to move in an abnormal fashion inside the joint.

Because the space between the bones of the joint is very small, as the abnormally mobile piece of meniscal tissue (meniscal fragment) moves, it may become caught between the bones of the joint (femur and tibia). When this happens, the knee becomes painful, swollen, and difficult to move.

The meniscus has several functions:

  • Stability – As secondary stabilizers, the intact meniscii interact with the stabilizing function of the ligaments and are most effective when the surrounding ligaments are intact.
  • Lubrication and nutrition – The meniscii act as spacers between the femur and the tibia. By doing so, they prevent friction between these two bones and allow for the diffusion of the normal joint fluid and its nutrients into the tissue which covers the end of the bone. This tissue is known as articular cartilage. Maintenance of the integrity of the articular cartilage is critical to preventing the development of post-traumatic or degenerative arthritis.
  • Shock absorption – The biconcave C-shaped pieces of tissue known as meniscii (cartilage in non-medical terms) lower the stress applied to the articular cartilage, and thereby have a role in preventing the development of degenerative arthritis.

source: this website