BRINGING SCIENCE TO TREATMENT

Wrist pain and the role of capitate

Tracy Ward discusses wrist injuries, with emphasis on the involvement of the carpal bone capitate, and how you can successfully modify your training when in possession of a wrist injury.

Wrist injuries are often underestimated within sport; however, they can account for between 3-9% of all athletic injuries1. Injury can occur from a single traumatic incident, for example falling on an outstretched hand, or impact from a ball or racquet, or more commonly can occur from repetitive overuse. Thus the wrist is susceptible to injury in almost any sport regardless of whether it is directly used.

The wrist joint is not designed to withstand large weight bearing or heavy loads like the ankle joint is, although these joints are often thought of in a similar manner because of their smaller size and distal origin of the limbs. Despite this, many sports and exercises involve weight bearing through the wrists or high impact directed to the joints, ie gymnastics, racquet and hand ball sports, strength training including press-ups, planks, and yoga poses. Sports played on hard surfaces can also traumatise the wrist as the body weight of the athlete can land upon the joint, and the hard surface (astro turf, ice, or racquet court will not absorb the shock as much as a forgiving ground surface). These activities all require wrist extension (the bending of the wrist backwards) and pain from this is often localised to the dorsal surface (back of the hand/wrist). This article will focus on extension injuries because they are the most commonly encountered.

Figure 1: The anatomical arrangement of the wrist carpal bones

Figure 1: The anatomical arrangement of the wrist carpal bones

A) Dorsal aspect (back of the hand) of the left hand [note]Maitland’s Peripheral Manipulation (2014). 5th Ed. Vol II. Churchill Livingstone. Elsevier. pp 327.[/note] B) Palmar aspect (palm surface) of the left hand

The wrist is a very complex joint and has an intricate array of muscles, ligaments and small bones within its small space, which must all work together for full function (see figure 1). Simply diagnosing an injury as a “wrist sprain” is not accurate and further diagnosis should confirm the exact structure damaged to direct mechanism of treatment.

The “wrist joint” is more anatomically known as the radiocarpal joint. This is the connection between the radius (forearm bone) and the proximal row (closest to the forearm, where the wrist crease occurs) of the carpal bones. The primary role of the radiocarpal joint is to allow movement of the hand upwards (extension) and downwards (flexion). This is stabilised by the radioulnar ligaments which connect the radius and ulna forearm bones anteriorly and posteriorly.

The carpal bones are then divided in to two rows. The proximal row consists from lateral (outside nearest the thumb) to medial of scaphoid, lunate, triquetrum, and pisiform. The distal row consists of trapezium, trapezoid, capitate, and hamate. Various small ligaments connect the carpal bones to each other, allowing fine movements around each other whilst being held securely in place2. These intricate connections allow the wrist to have the fine motor control that daily tasks require, as well as the strength for heavy gripping tasks.

The wrist joint is capable of approximately 85 degrees of wrist flexion and extension, and this movement occurs at the radiocarpal joint and the midcarpal joint (between the proximal and distal rows). It can also move side to side with 15 degrees of radial deviation (towards the thumb) and 45 degrees of ulnar deviation (towards the fifth finger)3. These movements again result from the radiocarpal joint but require the accompaniment of the midcarpal joint and intercarpal joints (joints in between the carpal bones). Therefore, some movement is required between these bones, but excess movement becomes problematic.

Common wrist problems

Wrist injuries can be sustained to the bones, muscle, tendon or soft tissue, or the cartilage. Within these categories a wealth of injuries may present. Bones can sustain stress fractures (thin hairline breaks), or complete avulsion or dislocation. Each carpal bone presents with a different complexity of problems should it become fractured and these are often related to interruption to their blood supply. Due to the inherent tight structure of the carpals the circulation can quickly become impaired and lead to avascular necrosis 4 Muscles and tendons may develop tendinitis or tendinopathy. Ligament strains may occur independently or could consequently cause carpal bone instability and excess movement. Finally,the triangular fibrocartilage complex (TFCC), which articulates the distal radius and ulna (forearm bones), as well as the ulna to the carpals and may tear and again present with instability of the wrist.

Common wrist problems
*Stress fracture to any of the carpal bones, with secondary complications;

*Soft tissue strain to muscle, tendon, or ligament; Dislocation of the carpal bones;

*Triangular fibrocartilage complex (TFCC) tear. This is a tear in the cartilage, and causes increased movement and instability at the wrist joint;

*Carpal bone instability.

Capitate subluxation

The scaphoid and hamate bones are often associated with fractures due to their location on impact; however, the capitate bone is more vulnerable to other sporting injury, primarily subluxation, because of its large size, elongated shape with a narrower distal end, and its central position, making it articulate with all seven of the other carpal bones. These properties can encourage subluxation to occur with wrist trauma, excess pressure to the joint or simply laxity and instability around the bone.

Carpal bone instability can be frequently misdiagnosed, or even completely missed, but a capitate subluxation has a typical presentation. The patient usually has no history of trauma but complains of prolonged months of pain and sometimes clunking at the wrist joint on load bearing exercises. After exercise there remains an intermittent niggle or ache in the localised region of the capitate.

Wrist extension would be limited and painful every time, whereas flexion would not be limited. Flexion can become painful over time though as the ligaments get pulled due to the capitate subluxation causing them to over stretch. On observation, there may be a visible bump at one point and a dip at the other end where the bone has moved out from its carpal groove.

Looking outside the box
If wrist extension is a crucial part of the athlete’s routine, eg handstands in gymnastics, then the athlete will adapt compensatory strategies to avoid full extension. This may alleviate the wrist pain but will impact on the rest of the upper limb.

Ultimately the exercise or activity will not be executed properly and could eventually result in injury because the weight distribution that should go primarily through the wrist will be applied elsewhere unexpectedly.

The structures above the wrist include the elbow, shoulder and shoulder blade, as well as the thoracic spine where the arm connects to the trunk. Each joint requires mobility, biomechanical alignment and stability. If there is a defect in the upper limb mechanisms then the small stabilising muscles will be more in demand and placed more under strain. It is crucial that the whole chain works together.

All of the muscles and fascia throughout the upper limb are continuously connected and in physiotherapy they are described as anatomy trains. The upper limb has two front arm lines (superficial and deep) and two back arm lines (superficial and deep). These anatomy trains suggest that impairment to one area then disjoints the rest of the train/body structures. So if the wrist is not able to fully extend, the forearm flexors can remain tightened, and therefore will also cause tightening on the biceps, pectorals and latissimus dorsi (the front arm lines). Likewise in the back arm lines, the trapezius, rhomboids, deltoid and arm extensors may weaken from excess contraction(4).

Solutions to wrist extension problems

Rehabilitation of a wrist injury should firstly focus on reducing pain and inflammation so that treatment can proceed effectively. This may involve the use of ice, pain killers, and, in severe circumstances, immobilisation of the wrist temporarily to allow no further strain to the injury and for the healing process to commence. Range of motion should be increased where possible, and this may involve manual therapy (as described below) if there is a physical block to movement. Progression then should focus on strengthening the weakened muscles and ligaments and restoring the wrist to sports specific conditioning, coordination and flexibility5. A phased return to sport should be implemented and this may require the use of protective supports or splints initially to gauge the suitability of wrist recovery for the sport’s demands.

1) Soft tissue stretching

Stretching of any of the upper limb muscles would be of benefit, since we earlier discussed how intricately linked the body’s connective tissues and fascia are. One tight muscle will have consequences elsewhere. Particular care should be taken to the forearm flexors and extensors and these can be stretched simply by placing the wrist in to full flexion or extension and holding for 30 seconds. More global stretching for the upper limb can be performed using the stretches pictured below.

Figure 2: Outstretching both arms as wide as possible for a stretch to the chest pectorals and forearm flexors

Figure 2: Outstretching both arms as wide as possible for a stretch to the chest pectorals and forearm flexors

Figure 3: Lying with the arms outstretched overhead allows stretching to the upper back muscles, chest muscles and throughout the arms

Figure 3: Lying with the arms outstretched overhead allows stretching to the upper back muscles, chest muscles and throughout the arms

Figure 4: This rotational stretch stretches through the body’s anatomical spiral line. It opens up the chest, shoulders, and torso for full body involvement

Figure 4: This rotational stretch stretches through the body’s anatomical spiral line. It opens up the chest, shoulders, and torso for full body involvement

2) Manual therapy

If the capitate has subluxed then it should first be reduced (put back in place) by a qualified orthopaedic physiotherapist. They will flex the wrist to relax the ligaments and apply a sudden downward thrust whilst applying traction to gap the space. A palpable clunk will signify the reduction of the capitate and normal carpal alignment should then be felt 6. Often once is enough to restore normal function and the athlete will feel an immediate relief of symptoms and regain full wrist extension. However, depending on the laxity of the carpal ligaments, subluxation may re-occur and the process should be repeated, as well as following the subsequent steps for prevention.

3) The use of hand bars

Where floor strength work is essential to training, such as press-ups and planks, rather than force the wrist to extend you can use hand bars. This allows you to grasp the handle and keeps the wrist in a neutral position throughout the exercise. This would be recommended for those who have a recurring capitate subluxation to minimise the strain and to prevent future injuries occurring.

4) Wrist splints/supports

For activities where wrist extension will occur routinely, the use of a splint or support can reduce the extent of extension the wrist has to endure. This may be a viable option if the injury is stable and will not receive significant loading; however splinting is not the solution to unstable or severe injuries where definite treatment should be the priority above all training 7. The type of support will depend on your sport, the injury, and how much movement you require to continue, therefore seeking advice from a sports physiotherapist would be beneficial here.

5) Strengthening exercises

Strengthening the surrounding muscles of the wrist is required to treat those that were weakened with the injury, but also to further absorb the shock to the wrist from impact and thus increase its protection.

Ball squeezes – This can be made sports specific by using your sports ball, racquet or likewise. Squeeze the object in your hand for five seconds and release; repeating for 3 sets of 10. This can be further specified by holding the object in the same positions you would in sport eg holding your tennis racquet in the backhand position as well as in front of you.

Wrist flexion – Start by holding a small weight in your hand with your arm down by your side and the palm facing away from you. Raise the palm upwards in to wrist flexion and repeat for three sets of 10.

Wrist extension – Repeat the above description but have the palm facing your body so that raising the back of the hand upwards brings the wrist in to extension.

Summary

  • *Wrist injuries can present in almost any sport from a trauma, fall, or overuse as the joint is complex with many structures vulnerable to damage. Injury can have a serious impact on an athlete’s training and function;
  • *The capitate bone is most vulnerable to subluxation due to its position, shape and size;
  • *Capitate subluxation can present with localised pain, a visible and palpable bump and groove, on-going pain but no history of injury, and limited wrist extension that is always painful;
  • *Treatment should consist of manipulation to reduce the subluxation, and then followed by stretching of the related muscles, and strengthening of the wrist muscles. Wrist splints can provide support and the use of hand bars may allow training to continue whilst recovering.
  1. Am J Sports Med. 2003; 31(6), 1038-1048.
  2. Sports Health. 2009; 1(6), 469-477.
  3. Maitland’s Peripheral Manipulation (2014). 5th Ed. Vol II. Churchill Livingstone. Elsevier. pp 327.
  4. Sports Health. 2009; 1(6), 469-477.
  5. Prim Care Clin Office Pract. 2005; 32, 35-70.
  6. Curr Orthop Pract. 2012;23(4), 318-321.
  7. Sports Health. 2009; 1(6), 469-477.
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