Abstract
Category:
Midfoot/Forefoot
Introduction/Purpose:
The burden of midfoot arthritis is staggering. Foot osteoarthritis affects over 16% of all adults over the age of 50, interfering with activities of daily living and leisure. Non-operative management often culminates in fluoroscopic guidance injections. Its management is troublesome for surgeons as conservative treatment is maximized because its surgical solution is oftentimes fraught with nonunions and other complications. The purpose of this study was to see how well surgeons are able to predict midfoot and transverse tarsal joint osteoarthritis on x-rays as it compares to CT and MRI scans.
Methods:
We reviewed the records of 117 patients (146 feet) with a diagnosis code of midfoot osteoarthritis who were treated from 2015 to 2019 at an academic medical center by a single surgeon. The mean age was 63.2 +- 10.7 years. The average BMI was 31.2 +- 6.4. Each of those patients had both plain radiographs and either a CT or MRI scan. Patients had weight-bearing anteroposterior and lateral radiographs according to a standardized protocol. Radiographs and advanced images were graded separately for the presence of joint space narrowing, subchondral cysts, and other signs of arthritis. We then compared how frequently a radiograph predicted an arthritic midfoot or transverse tarsal joint as compared to a CT scan or MRI using a paired t test.
Results:
The most common joints affected by arthritis were the 2nd TMT (83.5% by X-ray; 88.4% by CT) and 3rd TMT (71.9% by X-ray; 68.4% by CT). Advanced imaging showed a significantly higher rate of arthritis in the 1st, 4th, and 5th TMT as compared to X-rays. Only 20.2% of patients’ radiographs had a direct correlation with their CT scan. A CT scan showed one or two more affected joints by 23.6% and 17.6 % respectively, and rarely showed one or two less joints affected by arthritis, 6.8% and 0.6% respectively. Based on this data, a radiograph’s sensitivity and specificity vary wildly-from 86.0% and 57.8%, respectfully in the 3rd TMT to 43.8% and 96.0%, respectfully in the 1st TMT.
Conclusion:
Radiographs vary quite drastically in their sensitivities and specificities in diagnosing osteoarthritic joints in the midfoot and transverse tarsal joints. If intending to treat midfoot osteoarthritis with fluoroscopic injections, we recommend not relying on plain radiographs, but advanced imaging.