This week’s guest post is from Trevor Winnegge PT, DPT, MS, OCS, CSCS. Your may recognize the name, Trevor is a frequent commenter here on this website. Trevor has been practicing PT for over 8 years. He graduated from Northeastern University with a bachelors in PT and a master of science degree. He also graduated from Temple University with a Doctor of physical therapy degree. He is a board certified specialist in orthopedics and also a certified strength and conditioning specialist. He is adjunct faculty at Northeastern University, teaching courses in orthopedics and differential diagnosis. He currently practices at Sturdy Orthopedics and Sports Medicine Associates in Attleboro MA.
A Review of Several Complications Following Fracture of the Distal Radius
It is the time of year (at least here in the Northeast United States) where snow starts falling and the ground becomes icy. With these weather conditions comes an increase in the amount of slip and fall injuries seen by doctors and therapists. One of the most common fractures seen, comprising about 13% of all fractures, is the distal radius fracture. Whether these fractures are intra- or extra-articular; non-operative or post-operative, complications following this fracture often arise. These injuries are not always managed by a specialized hand surgeon, so it is important for therapists to be aware of some of the more common complications following this fracture.
Vascular injury and nerve injury can occur, however these are most likely to be picked up by the referring physician before they enter your clinic. Post-traumatic arthritis is common, yet takes longer to set in and may occur after discharge from therapy. I chose to focus this post on the following common forms of chronic pain after distal radius fracture: Scaphoid fractures, TFCC tears, Distal radioulnar joint instability/ulnar impaction syndrome, carpal instability and Extensor Pollicis Longus rupture.
The most common mechanism of injury for a distal radius fracture is a fall on an outstretched hand, or FOOSH injury. This is also the direct mechanism of fracture of the scaphoid carpal bone. This fracture can be sometimes overlooked due to the more pressing displacement of the distal radius. Signs to watch for in an associated scaphoid fracture include tenderness to direct palpation over the anatomic snuff box, swelling, and pain with wrist and thumb movements, as well as with gripping activities. The presence of swelling in the snuff box is variable, as some cases present with no swelling. Chen describes a scaphoid compression test, in which compression through the thumbs longitudinal axis should produce pain in the presence of fracture. Reliability and validity of this test are in question, as different studies have show mixed results, but I think it is a good quick test to add to the rest of your objective findings. Referral for scaphoid view xrays can be helpful. These are taken with clenched fist and wrist in ulnar deviation. If Xrays are negative and fracture is still suspected, an MRI or CT scan will assist in ruling in/out fracture. Failure to recognize a scaphoid fracture can result in non-union and chronic thumb and wrist pain.
The TFCC is comprised of a fibrocartilage disc interposed between the proximal row of carpals on the ulnar side of the hand and the distal ulna. It’s primary function is to enhance joint stability of the distal radioulnar joint and also acts to absorb some of the compressive forces through the hand and wrist. According to Richards et al, Triangular Fibrocartilage Complex, or TFCC, tears occur in 53% of extra-articular distal radius fractures and 35% of intra-articular fractures. Mechanism of injury for TFCC tears is also a FOOSH injury, typically while the forearm is pronated. Symptoms of a TFCC tear are pain just distal to the ulnar styloid process, clicking with pronation or supination which worsens when the wrist is in ulnar deviation and rotating, and pain with wrist/hand and gripping movements. Nonoperative PT care focuses on restoring wrist ROM and strength, as well as stability of the wrist.
Distal Radioulnar Joint Instability/Ulnar impaction syndrome
Instability of the distal radioulnar joint following a distal radius fracture occurs in conjunction with a TFCC tear. Other factors suggestive of instability are widening of the joint on x-ray, a positive ulnar variance, and a shortened radius. Neutral ulnar variance is when the borders of the radius and ulna are level across in height. A common complication following fracture of the distal radius is when the radius shortens. This leads to what is know as a positive ulnar variance. Positive ulnar variance is used to describe a forearm where the distal ulna is no longer in line with the distal radius, resulting in the ulnar being longer. The amount of variance is measured on xray and is usually millimeters. (For the record, a negative ulnar variance occurs when the ulna is shorter). In a neutral (normal) variant wrist, the radius absorbs 80% of the weightbearing load, and the ulnar 20%. In a wrist with positive ulnar variance, the ulnar weight bearing load increases to as much as 42%. Over time, this increased load can lead to a condition called ulnar impaction syndrome. This is one of the more common reasons patients have chronic ulnar sided wrist pain following a distal radius fracture. This occurs when the distal end of the ulna with its increased weightbearing load, wear through the TFCC. Symptoms include restricted ROM-particularly with supination/pronation and ulnar deviation. It can also lead to lunate-triquetral instability and carpal chondral lesions. PT management would include strengthening/stability training and restoring rom. However, often times another procedure is indicated. Surgical options include an arthroscopic waffer procedure, osteotomy, or a hemiresection arthroplasty.
Figures: Ulnar variance (left), positive ulnar variance – note the radial border of the ulna is elevated (middle), negative ulnar variance – note the radial border of the ulna is depressed (right).
I mentioned lunate-triquetral instability occurring as a result of the ulnar positive variance following a distal radius fracture. In addition, and more commonly, the scapholunate joint often becomes unstable following a distal radius fracture. It is estimated that in 54% of distal radius fractures, there will be an associated scapholunate instability. Symptoms are pain over the joint line with weight bearing activity, clicking, weakness and a positive instability with joint play testing. Treatment includes splinting, stability and strengthening exercises and activity modification. If a patient does not modify their activity that causes pain, it can lead to a scapholunate dissociation over time, where the scaphoid dislocates. This often requires reduction and internal fixation. Symptoms of this are extreme pain and functional loss of strength, and is easily picked up on x-ray.
Lastly, I want to review the extensor pollicis longus (EPL) muscle and tendon. This is unique in that it occurs following a distal radius fracture in up to 3% of all cases, yet it is poorly understood why this occurs. The EPL inserts on the distal phalanx of the thumb, and acts as a joint extender of the thumb. Rupture of the EPL can occur up to 8 weeks after the initial distal radius fracture. Since it has a poor blood supply, it is postulated that chronic tenosynovitis following this injury wears away the tendon sheath, making it vulnerable to rupture. Testing for a rupture is a simple manual muscle test, where you block the IP joint of the thumb and isolate the distal phalanx. You then ask the patient to extend the distal phalanx and if they are unable to or have trouble doing so, rupture of this tendon should be suspected.
In summary, there are numerous possible complications following a distal radius fracture. I highlighted several of the more common ones. Chronic wrist pain can be difficult to treat as a therapist and aggravating for the patient. Being aware of the possible causes of such pain can lead to a quicker proper diagnosis and preservation of hand and wrist function.
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H. S. Cheng, L. K. Hung, P. C. Ho, J. Wong (2008). AN ANALYSIS OF CAUSES AND TREATMENT OUTCOME OF CHRONIC WRIST PAIN AFTER DISTAL RADIAL FRACTURES Hand Surgery, 13 (01) DOI: 10.1142/S0218810408003748