It sounds like you have a fracture of the ulnar styloid — a small projection of bone at the bottom of the ulna. The ulna is one of the two bones in your forearm. The top of the ulna forms part of the elbow. The bottom or distal end connects with the wrist.
A fall such as you had is the most common cause of ulnar styloid fractures. Even with immobilization in a cast, nonunion at that site is relatively common. Sometimes patients (like you) are aymptomatic (without pain or other distressing symptoms). For those patients who have wrist pain, loss of motion and function dictate the need for surgery.
Your question is a good one and something you should discuss further with your surgeon. There are other factors that should be taken into consideration. One of those factors is whether or not there are any torn or damaged ligaments, cartilage, or other soft tissues in the wrist as a result of the injury.
A partial or complete (full-thickness) tear of the triangular fibrocartilage complex (TFCC) will require repair. The triangular fibrocartilage complex (TFCC) describes a group of tough ligaments that hold the radius and ulnar together. The TFCC also connects the ulnar styloid to the bones in the wrist. The TFCC is a major stabilizer of the radioulnar and wrist joints.
Most of the time, an injury of the TFCC leads to pain on the little finger side of the wrist. Studies show that surgery to repair the broken styloid hasn’t been very successful. Removal (resection) of the broken fragment is often necessary — especially for those individuals who are experiencing pain as a result of abnormal motion or wrist instability.
You may need further diagnostic testing to evaluate what else might be going on. Magnetic resonance imaging arthrography of the joints may provide the additional information you are going to need to answer this question. Your surgeon may propose performing an arthroscopic exam. Arthroscopy is the only way to be 100 per cent certain just what is going on. Treatment can then be specific to your problems.