Comparison of Three Fixation Techniques for Displaced Distal Radius Fractures

Distal radius fractures are the most common fracture to occur in the adult population, and those which are displaced but maintain joint congruity are the most common subtype. Locking-plate technology represents a true advance in the fixation of these fractures, especially in view of the ever increasing incidence of these injuries in an ageing and osteoporotic population throughout Europe and North America. These plates permit rigid fixation, even in osteopenic bone, while avoiding any tethering of soft tissues, as seen with external fixation and percutaneous pinning. For these reasons, this mode of fracture fixation has rapidly gained popularity. Unfortunately, there is presently little evidence to support their use over the more traditional methods of fixation (percutaneous pinning, external fixation). In addition, the technique for their application is more invasive and their cost is considerably greater than these latter two techniques. As such, it is pertinent to evaluate, in a scientifically sound fashion, the outcome of fixation with the three types of implant included in this study. The results of this clinical trial will allow the orthopaedic community to confidently recommend the fixation method which provides the optimal functional, clinical, and radiographic outcome for a patient suffering a displaced distal radius with preserved joint congruity.

Null hypothesis: There is no difference in the functional, clinical, and radiographic outcomes of the three treatment methods.

Hypothesis: Given the locking nature of modern screw-plate constructs, which produce excellent fixation even in osteopenic bone and permit early range of motion exercises; and given that plate fixation, in contrast to external fixation and percutaneous pinning, does not tether muscle, tendon, or capsule; plate fixation with a volar fixed-angle device should permit earlier and more aggressive rehabilitation and more rapid and complete regain of hand and wrist function when compared to stabilization with external fixation or percutaneous pinning.

Fractures of the distal radius, the most common fracture to occur in adults, are increasing in incidence and cost due to ageing of the population and the link with senile osteoporosis. Young adults also suffer these injuries albeit involving higher-energy mechanisms. Closed reduction and casting is often unsuccessful in maintaining adequate alignment and length, both of which are crucial to a successful outcome. Thus, there has been a trend toward surgical treatment of these fractures. In fractures with preserved joint congruity, 3 fixation options exist: percutaneous pinning (Kapandji technique), non-spanning external fixation, and locked-plates. Locked-plates represent a significant advance in the fixation of fractures, especially in osteopenic bone, although their role in distal radius fractures has yet to be defined adequately. The Cochrane Group undertook a meta-analysis of RC trials "to determine when, and if so what type of, surgical intervention is the most appropriate treatment for fractures of the distal radius in adults." The authors concluded: "there is a need for good quality evidence for the surgical management of these fractures." The aim of this randomized clinical trial is to compare the functional, clinical, and radiographic outcomes of these 3 methods. The results will clearly guide surgeons in the choice of optimal technique.

This multicenter prospective randomized trial will involve the Canadian Orthopaedic Trauma Society (COTS), an association of trauma surgeons involved in collaborative outcomes research with a proven track record of research and publication. Patients with a displaced distal radius fracture with joint congruity who meet all eligibility criteria and provide consent to participate will be randomly assigned to reduction and fixation with one of three methods: volar locked-plate, percutaneous pinning and cast (Kapandji intra-focal technique), or non-spanning external fixation. Patients will undergo physiotherapy according to protocols adapted to fixation technique. Evaluation at fixed intervals will include functional, clinical, and radiological parameters. Functional evaluation will include the PRWE, DASH, and SMFA questionnaires. Clinical outcome will evaluate range of motion, pinch and grip strength, and dexterity. Standard radiographic parameters will be measured. The primary outcome measure will be functional outcome as measured with the PRWE. Appropriate statistical analyses will be performed on the data. Sample size calculation reveals the need for 108 patients per treatment arm. A census of the centers committed to the study predicts a 12-18 month recruitment period. Patient follow-up will end at 2 years.

Eligibility Criteria:
Patient Inclusion Criteria:

1. Over 18 years of age with skeletal maturity, and consenting to participate.
2. A displaced distal metaphyseal radius fracture (AO type A2, A3, C1, C2--- appendix 1) with a congruous joint surface (\< 2 mm displacement) either before or after closed reduction.
3. 21 days or less between injury and surgery.
4. The patient must be medically fit for anaesthesia.
5. The patient must have the mental faculties to participate in post- operative evaluation.

Patient exclusion criteria:

1. Significant bone disorder (osteomalacia, hyperparathyroidism) which may impair bone healing (not including osteoporosis).
2. Open fracture.
3. Neurovascular injury requiring repair in same limb.
4. Ipsilateral limb injury.
5. Active infection in area of surgical approaches.
6. Prior wrist injury or degenerative condition, or congenital wrist anomaly.

Fracture inclusion criteria:

Patients sustaining a displaced AO type A2 A3 C1 or C2 distal metaphyseal radius fracture with preserved joint congruity before (52) or after closed reduction are eligible for inclusion. Radiographic criteria for an unacceptable closed reduction include:

1. Palmar tilt \< 00.
2. Radial inclination \< 150.
3. Radial shortening \> 5 mm.
4. Articular step or gap \> or= 2 mm.

Fracture exclusion criteria:

1. Fractures with apex dorsal angulation ("Smith fracture") will be excluded as they are not amenable to treatment with all three methods.
2. Less than 1 cm of intact volar cortex on the distal fragment as this is the minimum necessary for non-spanning external fixation (40, 48).