Patients who suffer from severe rotational instability of the forearm and pain in the Distal Radio-Ulnar Joint (DRUJ), may be able to attribute these symptoms to DRUJ fractures, ligamentous disruption or ulnar styloid fractures.
Osteoarthritis (OA) and rheumatoid arthritis are also frequent causes of DRUJ pain. There have been few advances in the techniques and implants for treating DRUJ pain in the last 30 years.
Treatment options have ranged from wrist or DRUJ fusions to a large variety of excision techniques. However, the ulna is beginning to interest the medical community as an anatomic region deserving of better treatment options.
Historically, injuries affecting the forearm and wrist have been treated with surgical techniques necessitating partial or complete ulna resection.
The most common treatment approaches have been the Darrach procedure, the Sauve-Kapandji procedure and a Hemi-Resection Interposition (HRI), also referred to as the Bower's procedure.
These procedures are extensively documented. Each relies on the
removal of bone mass (except for fusions) with no replacement or substitution of the excised bone.
As these standard practices do not yield desirable results for all patients, many surgeons and device manufacturers have sought an alternative treatment modality.
THE DARRACH PROCEDURE
The Darrach procedure is viewed as the traditional approach to excising the arthritic surface of the DRUJ. It dates back to 1912 when William Darrach first described it.
There are several variations, some of which call for the complete excision of the distal ulna. Others call for a limited excision leaving a partial interposition of the soft tissue to the remaining ulna.
While this is a common procedure, complications may include distal forearm instability, convergence and other complications. The primary cause is the removal of the ulnar head and destabilisation of the ulna, which, ironically, is the source of pain relief.
THE SAUVE-KAPANDJI PROCEDURE
The Sauve-Kapandji procedure involves the resection of several centimetres of ulnar bone mass close to the DRUJ, yet the ulnar head itself remains intact. The ulnar head is then fused to the distal radius. The presence of the distal ulnar stabilises the joint.
This is often preferred over the Darrach procedure. However, the patient is still likely to suffer from convergence, reduced grip strength and reduced rotational range of motion.
The HRI was developed by William Bowers. This involves a partial resection of the distal ulna. The Triangular Fibro Cartilage (TFC) is left intact, and tendon or joint capsule is placed in the void to serve as a spacer.
This has had good success in younger patients, yet the clinical outcome still leaves patients with reduced grip strength, amongst other potential complications.
ULNAR HEAD ARTHROPLASTY
Recently, a new approach has emerged for treating DRUJ instability, arthritis of the distal ulna and traumatic injury – distal ulnar arthroplasty.
Expanded potential indications may include patients suffering from OA, rheumatoid arthritis, ulnar impaction with OA, failed Darrach procedures, failed matched resections, post-fracture management of the distal ulna and ulnar impaction without OA in patients who refuse to quit smoking.
Over the last five years, several device makers have developed ulnar arthroplasty prostheses.
The benefits to patients who receive an ulnar head implant include pain relief, good stability to the DRUJ and better forearm stability by diminishing convergence.
To examine the benefits and possible complications of ulnar arthroplasty, one trial looked at 14 ulnar head arthroplasty recipients. The age of the patients in this study ranged from 41 to 73 years, with an average age of 53. Eight were male and six were female.
In reviewing the mechanism of injury, five patients suffered a traumatic injury to the wrist with resultant post-distal radius fracture complications, five suffered from primary arthrosis of the DRUJ, one patient had had a previous Darrach procedure that failed and two suffered from TFCC disruptions with OA (in smokers). The average follow-up for these cases was 2.3 years, with a range of two to four years.
MATERIALS AND METHODS
This study used a prosthesis that was anatomically designed to replicate the distal ulnar head and its contact within the sigmoid fossa of the distal radius. The prosthesis has a cobaltchrome head and a titanium plasma sprayed stem. It may be applied with or without cement.
All of the patients in this retrospective study did not require cement to complete the applications. The implant is available in a range of stem and head sizes to accommodate patients of differing anatomy, including a reconstructive stem (with an elongated stem collar to compensate for traumatic bone loss of the distal ulna).
It should be noted that these ulnar head implants employ alternative materials such as ceramics, for similar applications. Each of the patients involved in this study received one implant (no bilateral applications).
Of the fourteen patients who received an implant with the anatomically designed prosthesis replicating the distal ulnar head, 13 reported reduced pain, while one patient had the implant removed due to continued wrist pain.
This particular patient experienced an Essex-Lopresti lesion due to a work accident that resulted in continued pain even after the prosthesis was explanted.
There were no infections recorded in any of the patients. The remaining 13 patients all exhibited increased range of motion and forearm stability.
Within the patient population in this study, three were worker's compensation cases. This is especially significant as two of these patients returned to work with excellent range of motion.
While continuing research is required, it is possible that this procedure could become an important tool for treating work-injured patients with DRUJ problems.
Distal ulnar arthroplasty is a reliable procedure in appropriate cases. Thus far it seems to address the need for immediate pain relief, but unlike traditional treatment options, yields greater stability within the forearm and increased grip strength.