This prospective randomized multicenter study evaluated a total of 333 patients at 23 investigative centers over a period of 29 months with a one-year follow-up. Patients were stratified and randomized based on fracture type, bone mineral density, hand dominance and the type of designated conventional treatment i.e. cast or external fixator (as determined by the physician). 161 study patients were treated with Norian SRS within 5 days after the injury. This included a closed reduction followed by an injected of SRS cement into the metaphyseal bone defect either through a dorsal percutaneous technique (1st 12 patients) or a limited open technique (all subsequent patients due to a high rate of extravasation and difficulty with injection). The fracture voids were prepared by evacuating the hematoma and impacting the crushed metaphyseal bone to obtain a stable rim. The cement was allowed to harden for 10 minutes, the wound was subsequently closed and a short arm cast was placed for two weeks. A removable splint was placed for 4 additional weeks. Supplemental K-wires were used in specific instances such as displaced articular fractures that remained unstable following reduction or fractures considered at risk for displacement during injection. The K-wires were intended for use only to resist non-compressive loads.
The control group underwent a closed reduction following by the application of a short arm cast or an external fixator depending on the preference of the surgeon. Percutaneous pins were also placed at the discretion of the investigator. Immobilization in the control group lasted from 6-8 weeks. Significant clinical differences were noted at 6-8 weeks postoperatively with better grip strength, wrist range of motion, digital motion, use of the hand, social and emotional function, and less swelling in the Norian SRS group. By 3 months, only digital motion remained significantly better in the Norian SRS group. By 1 year, there were no clinical differences between groups.
Radiographically, there was a greater ulnar variance in patients treated with Norian SRS (+2mm) than in the control group (+1.4mm). Forty-six percent of the Norian SRS group reported a complication and 51% of the control group experienced a complication, which was not statistically significant. The control group, however, had a significantly higher infection rate (17%) than the group treated with Norian SRS (3%); the infections were related to the external fixator pins or Kirschner wires. Four patients were noted to have intra-articular extravagation of cement and 70% were noted to have extraosseous extravasation. The amount of cement that was known to have extravasated overall diminished over time in all instances. There was no radiographical evidence of arthritis in the patients with intraarticular extravasation. There were 6 tendon ruptures in the study group compared to 2 in the control group, which involved the extensor pollicis longus tendon. One patient in the SRS group developed osteomylitis requiring removal of the SRS cement, IV antibiotics, and placement of an external fixator. Loss of reduction was noted in 29% of the patients in the SRS group and 25% in the control group, which was not statistically significant.
This study establishes the safe use of Norian SRS for the treatment of distal radius fractures. Most differences were noted at 6-8 weeks with the Norian SRS group achieving greater function and increased range of motion. This was most likely related to early initiation of motion. However, range of motion, strength and function were all similar by 1 year. This reinforces other studies that suggest that early motion most likely does not change the ultimate functional result following distal radius fractures. The notable 50% complication rate in both groups may be related to the rigorous and prospective nature of the study. Further studies may be necessary to confirm whether there is a higher rate of EPL tendon ruptures associated with Norian SRS use as well as the 1 case of osteomylitis. In addition, no account was made of the relative cost involved with each treatment, which may ultimately be a significant factor in the use of these bone cements in our treatment algorithms. The authors recommend that if Norian SRS cement is used for fracture stabilization, the limited approach should be used with supplemental K-wires placed prior to cement injection and left in place for a minimum of 2 weeks post operatively. They recommend the removal of all extraosseous and intraarticular cement noted at the time of injection.
J of Bone and Joint Surgery