As an orthopedic surgeon specializing in the hand, wrist, and elbow problems at NewYork-Presbyterian and Columbia, Robert J. Strauch, MD, has treated countless patients with fractures of the ulnar and radial shaft, which are relatively common fractures of the upper extremity. A seasoned researcher, Dr. Strauch pursues studies designed to answer clinical problems that he encounters in his practice. Most recently, he and Nathan C. Winek, MD, a clinical fellow in microsurgery, hand, and upper extremity surgery at Columbia, conducted a study on hardware used for open reduction internal fixation, which has been published in the Journal of Hand and Microsurgery.
Below, Dr. Strauch discusses the challenges with the current standard of care for an ulnar fracture and what was learned from this study that can be applied in future cases.
Research Background
The current standard of care for operative fixation of an ulnar shaft fracture involves 3.5mm plating with 3.5mm screw fixation. Recently, we were operating on an ulnar fracture in a female and in looking at the plate and screws, they appeared overly large for the bone. It is not uncommon that prominent ulnar hardware can cause irritation, often prompting removal of the hardware. In fact, studies have shown that 47% of patients who underwent ulnar shortening osteotomy with plate fixation complained of hardware irritation, with 32% going on to have the hardware removed. When you insert a screw as large as 3.5mm, it takes up a greater percentage of the bone and, subsequently, if you need to remove the plates and screws for whatever reason in the future, it leaves large holes in thinner bones that could potentially increase the rate of refracture.
With this in mind, we sought to determine if 3.5mm screws and plates are always appropriate regardless of the diameter of the ulna. We considered that perhaps it would be reasonable to use a smaller plate and smaller screws in certain patients. The purpose of our study was to measure diameters along the length of the ulna to provide information on screw length and appropriateness of 3.5mm screws and plate location.
Research Methods
To explore our theory, we collaborated with Paulette Bernd, PhD, director of the Gross Anatomy Course at Columbia, who provided access to study upper extremity cadaver specimens. We examined 10 cadaver specimens – five females and five males – average age of 83.6 and 78.8 years, respectively. We measured the length of the ulna and then divided by four and performed transverse osteotomies along the ulna at ¼, ½ and ¾ of its full length. The diameter of the ulna at these locations was then measured in a radio-ulnar direction as well as a volar-dorsal direction.
Our findings raise the question of whether 3.5mm screws in the distal and midshaft ulnar diaphysis in females is advisable. It may make sense to use smaller 2.7mm screws.
— Dr. Robert J. Strauch
Key Findings
We know that the ulna becomes narrower closer to the wrist, especially in women. We found that the smallest diameter in both the female and male specimens was in the distal ¾ shaft measured in a volar-dorsal direction with an average of 9.1 mm and 12 mm. The average volar-dorsal measurement was less than radio-ulnar measurement at all locations. The diameters increased along the ulna heading proximally.
Our findings raise the question of whether 3.5mm screws in the distal and midshaft ulnar diaphysis in females is advised. Removing the 3.5mm screws in the mid and distal ulnar shaft in females can leave a hole corresponding to 23% and 27% of the bone, which can contribute to the development of a stress riser fracture. Therefore, it may make sense to use a smaller 2.7mm screw to retain more bone.
There have been few, if any, studies on this particular issue. Our research sheds light on the importance of considering the size of the plates and screws as compared to the size of the ulna to avoid adverse consequences. While a small study, it opens avenues for biomechanical analysis comparing the strength of smaller versus larger hardware and potentially a clinical study on outcomes.
