DISTAL RADIO-ULNA JOINT (DRUJ)
What is distal radio-ulna joint?
The distal radio-ulna joint (DRUJ) is the distal (far) joint between the radius and ulna bones. The forearm is made of 2 bones: the radius; and the ulna. They are linked just below the elbow and just above the wrist. In between they do not meet but are linked by a long stout ligament. The joints at the elbow (proximal radio-ulna joint) and at the wrist (DRUJ) allow the radius to rotate around the ulna thus allowing forearm movement: pronation - turning the hand down to the floor; and supination - turning the hand up to the ceiling. The distal ulna bone also gives support to the wrist bones. At the far end of the ulna is a ligament complex called the triangular fibrocartilaginous complex (TFCC). This stabilises the radius to the ulna and helps support the wrist.
The problems at the DRUJ are most commonly instability following an injury and occasionally DRUJ arthritis. (Ulno-carpal impaction/abutment/impingement occurs when the ulna bone bumps against the wrist bones. This could be considered a DRUJ problem but is better considered under wrist ligament injuries - see information sheet).
DRUJ instability: Wrist fractures are often associated with tears of the TFCC or fracture (break) of the ulna styloid to which the TFCC is attached. In most cases this heals back well with either no instability or mild instability but with minimal or no symptoms. Some patients have aching over the ulnar (little finger) side of the wrist, some stiffness particularly into supination (turning the palm up) and reduced grip strength. Wrist fractures and soft tissue injuries occur a all ages so these problems can present at any age.
DRUJ arthritis: aWear and tear (osteoarthritis) is uncommon. It may follow a fracture although very few fractures give rise to DRUJ arthritis. Mostly it occurs for no obvious reason. The patients are typically late middle age or older (60+). The have a combination of pain over the DRUJ and stiffness in forearm rotation both pronation and supination. One or the other may predominate.
Why does it occur?
DRUJ instability: The problem is one of damage to the ligamentous complex that secures the radius to the ulna. When weakened this allows for excess movement at the DRUJ which may be both uncomfortable and cause stiffness.
DRUJ arthritis: Normal joints are lined with articular cartilage and lubricated with a little bit of fluid that is continually renewed. Either due to general wear and tear or a structural abnormality in a joint such as a previous fracture (break) or operation the lining of the joint thins and may wear away leading to bone rubbing on bone. This is not necessarily painful but may be. The joint tries to protect itself by forming a little more new bone at the edges and producing more joint fluid. These lead to stiffness and deformity.
What happens if nothing is done?
(This is referred to as the natural history i.e. what happens if Nature runs its own course.)
DRUJ instability: The symptoms tend to stabilise out within a year or so of injury. By then people either have problems or do not. Unless there is a change in activity such as undertaking heavier work then the symptoms tend not to change long term.
DRUJ arthritis: Once arthritis has started it will almost inevitably progress i.e. there will be increasing wear of the joint surfaces. This does not however mean that the patient's symptoms will necessarily increase although they may. This can lead to increasing pain and stiffness and hence disability.
Making the diagnosis
The Hand specialist who sees the patient will ask questions about their symptoms, when they started, how they progressed, what treatment (if any) they have had and other questions relevant to the problems. They will then examine the patient looking at the elbows, wrists and hands. Stressing i.e. pushing on the affected area is usually uncomfortable. It is usually necessary to demonstrate some tenderness to confirm the site of the symptoms but this should not be too painful.
What test(s) might be performed?
Tests (also known medically as Investigations) include X-rays, scans, blood tests and particularly in the hand electrical tests (known as EMGs or Neurophysiology). These may be used to help make or confirm a diagnosis after a patient has described their symptoms and been examined.
The diagnosis is usually obvious after listening to and examining a patient. Typically an X-ray is requested on the same day to delineate the extent of joint damage, although the X-ray findings do not correlate well with the symptoms with some patients having few X-ray changes but marked symptoms and vice versa.
For instability special scans may be necessary to help delineate the problem further. Typically a CT scan helps show joint alignment best and an MRI scan showe the soft tissues best:
A CT (or CAT) scanner is a short large open tunnel. The patient lies on a bed and passes through the tunnel whilst X-rays are shone from various directions at the area of the body being investigated. It is particularly useful for showing bone abnormalities but less good at investigating soft tissue problems. The films will be reported by a radiologist but also reviewed by the Hand specialist who will advise the patient accordingly.
An MRI scanner is usually a short tunnel which the patient's arms and top half of the body go into. Usually the arms are stretched out in a "superman" pose which is a little uncomfortable but generally well tolerated. Once in the tunnel a loud magnet is spun around and images of the bones and soft tissues created. Some people find the tunnel rather claustrophobic. If any patient doubts whether they would tolerate the scan they are best advised to visit the scanner department in advance. The films will be reported by a radiologist but also reviewed by the Hand specialist who will advise the patient accordingly.
What are the non-operative treatments?
Treatment should start with non-operative options. The first step is activity modification which the patient may well already have tried. Pain killers (analgesics) particularly anti-inflammatory analgesics, such as Ibuprofen (Nurofen) and Diclofenac (Voltarol) can be very helpful for the pain in arthritis. These can be applied as a gel, massaging the area, or taken orally, assuming there is no history of indigestion. A splint for certain activities can also be of value particularly for instability. Some patients find splints very helpful, other not at all. If these measures are insufficient then a steroid injection may be recommended particularly for arthritis. An injection is given of a long-acting steroid, such as Depomedrone or Triamcinolone, with some local anaesthetic into the joint at the bottom of the thumb. The body naturally produces steroids to help dampen down inflammation. This appears to be one of the actions at this site. Success cannot be guaranteed but in 70-80% of patients there is some significant benefit. How long this lasts is unpredictable. Some people only have a few weeks or months of benefit. Others may have years or even life-long benefit such that they do not require further treatment, although may still have some mild on-going symptoms. If one injection provides only short term benefit then it may well be repeated for arthritis but probably not for instability. Patients often ask how many injections can be given. There is no set rule about this. Typically, however, a second injection will work a little less well than the first (although this is not inevitable). By the time three injections have been given, if this is over a shortish period, i.e. less than 1 year, then it is unlikely the any further injections will be successful and most surgeons would recommend an alternative approach. If, however, injections are only required infrequently, perhaps once every 2-3 years, then having a fourth or fifth injection would, in themselves, be a lot safer than having an operation, and if they give benefit this is reasonable. There are risks. The biggest risk is of failure. There are risks of some pain for a few days, although that is usually minimised by taking pain-killers, starting while the area is still numb from the local anaesthetic. In theory there is a risk of infection, but this seems very rare and has not occurred in our Practice in over 10 years. The main other risk is some thinning of the skin. This can present with some pallor and a little less bulk at the site and occasionally an increased tendency to bleeding if the area is knocked. This is not common with this injection but is common with some other injections. If it does occur then that is a relative contra-indication to further injections, i.e. the patient's surgeon would probably decide not to go ahead with further injections because of the risks of further local damage.
What does the operation involve?
For instability of the DRUJ there are a number of possible operations highlighting the complexity of this problem. The 2 main operations are either: ligament reconstruction; or ulna shortening.
Ligament reconstruction: This is the preferred option as in theory it directly addresses the problem. It is, however, difficult to reconstruct full ligament function and as yet there is no fully proven technique although there are a number of preferred and increasingly accepted techniques. The operation is performed under regional block/general anaesthetic. i.e. the patient's arm is numbed or they are asleep. The surgeon makes a cut over both the back and the front of the wrist. A "spare" tendon or part of a tendon is used to reconstruct the ligament complex. The deep tissues are closed and the skin is then stitched up usually with absorbable stitches. A supportive plaster of Paris is applied and the patient's arm(s) elevated.
The total time in hospital is usually 4-6 hours, although occasionally an overnight stay is required.
Ulna shortening: In this operation the ulna bone is cut near the wrist, shortened by typically 1-3 mm and held with a plate and screws. This acts to tighten the remaining ligaments linking the radius and ulna bones and can be very effective in resolving instability. Each operation has strengths and weaknesses. The Hand specialist should help the patient to decide on the correct way forward. The operation is almost always performed under regional block/general anaesthetic. i.e. the patient's arm is numbed or they are asleep. The surgeon makes a 6-8cm cut over the ulnar border of the distal forearm. The ulna bone is cut by a predetermined amount and held in its new shortened position with a plate and screws. The deep tissues are closed and the skin is then stitched up with absorbable stitches. A supportive plaster of Paris is applied and the patient's arm(s) elevated.
The total time in hospital is usually 6-8 hours.
For arthritis of the DRUJ there are a number of possible operations again highlighting the complexity of this problem. The 2 main operations are either: excision of the distal ulna; or distal ulna replacement (hemi-arthroplasty):
Excision of the distal ulna: This is a well established called a Darrach's procedure. It removes the site of the arthritis and resolves pain. In low demand patients such as the elderly (70+) or those with rheumatoid arthritis is works very well. Higher demand patients particularly younger males tend to have problems with pain and instability. In response to this a hemi-joint replacement has been developed replacing the end of the ulna (see below).
The operation is performed under regional block/general anaesthetic. i.e. the patient's arm is numbed or they are asleep. The surgeon makes a cut over both the back and the front of the wrist. The end of the ulna bone is removed. In time the space will form with scar tissue forming a pseudo joint. The deep tissues are closed and the skin is then stitched up usually with absorbable stitches. A supportive plaster of Paris is applied and the patient's arm(s) elevated.
The total time in hospital is usually 4-6 hours.
Distal ulna replacement (hemi-arthroplasty): This is a recently developed operation that appears to give good early and mid-term results but the long term results are not known.
The operation is performed under regional block/general anaesthetic. i.e. the patient's arm is numbed or they are asleep. The surgeon makes a cut over both the back of the wrist. The end of the ulna bone is removed and replaced with a piece of metal shaped like a new end of ulna. The deep tissues are closed and the skin is then stitched up usually with absorbable stitches. A supportive plaster of Paris is applied and the patient's arm(s) elevated.
The total time in hospital is usually 6-8 hours.
What happens in the next few weeks?
The care of the hand in the post-operative period is very important in helping to ensure a good result. Initially the aims are comfort and elevation. These are met by keeping the hand up (elevated) especially in the first few days and by use of a long acting local anaesthetic (Bupivicaine). The local anaesthetic lasts at least 12 hours and sometimes 48 hours. Patients should start taking painkillers before the pain starts i.e. on return home and for at least 24 hours from there. This way most of our patients report little or any pain.
The patient is reviewed in clinic within 2 weeks of the operation. Typically dissolvable stitches are used so they should not require to be removed. For ligament reconstruction progress tends to be a little slower than for ulna shortening, distal ulna removal or ulna replacement.
Most of the movement gained following surgery occurs in the first 6 weeks although some further late movement often occurs. Thus the early post-operative period must be used productively to ensure a good result. The key is regular long gentle stretches both into supination and pronation. The Hand surgeon should be guide their patient carefully. Ideally the stretches should be performed for 5 mins in each direction (feeling the stretch but without pain) once an hour. In practical terms most people mange 5-6 times a day. Elevation and icing the elbow also help reduce swelling and thus pain and improve movement.
The hand can be used for gentle activity after the first few days. Most patients can drive after 6 weeks or so. Most patients return to work in 4-6 weeks, but this varies with occupation; heavy manual work usually takes a good 3 months. The wound should be massaged by the patient 3 times a day with a bland soft cream for 3 months once the wound is well healed (typically after 2 weeks). This reduces the scar sensitivity which can be a nuisance. Patients should avoid heavy use of the wrist or hand for at least 6 weeks and often longer following the operation.
What are the results of the operation?
At least 80% of patients in studies say they have a good or excellent result following this operation, with relief of the pain and a reasonable range of movement. The key is choosing the right operation for the right patient. The long-term results of joint replacements are not known but so far seem reliable for at least 5 years. About 10-20% of patients who have ulna shortening require subsequent removal of the metal plate at a later operation usually at least 1 year following surgery. This is typically for local discomfort from the plate.
Are there any risks?
All interventions in medicine have risks. In general the larger the operation the greater the risks. For distal ulna surgery the risks include:
- The scar may be tender, in about 20% of patients. This usually improves with scar massage, over 3 months.
- Aching at the site may last for several months
- Grip strength can also take some months to return to normal.
- Stiffness may occur in particular in the fingers. This is usually short-term and only infrequently requires physiotherapy. But it is very important that it is resolved quickly to avoid permanent stiffness. This occurs rarely but can do associated with CRPS (see below)
- Numbness can occur around the scar but this rarely causes any functional problems.
- Wound infections occur in about 1% of cases. These usually quickly resolve with antibiotics.
- For joint replacement there is a risk of long-term joint replacement failure requiring reoperation.
- For joint fusion there is a risk of failure to achieve bone to bone union of to gain union with some malalignment. Either may (but not of necessity) require reoperation.
- Chronic Regional Pain Syndrome "CRPS". This is a rare but serious complication, with no known cause or proven treatment. The nerves in the hand "over-react", causing swelling, pain, discolouration and stiffness, which improve very slowly.
- Any operation can have unforeseen consequences and leave a patient worse than before surgery.