From the Research
Radiology may fail to detect a union at the midfoot after a Lapidus procedure due to several factors, including the limitations of standard radiographs in assessing complex three-dimensional joints and the potential for metallic hardware to create artifacts. The most recent and highest quality study on this topic is from 2020 1, which highlights the importance of clinical assessment in conjunction with radiographic evaluation. Some key points to consider include:
- Standard radiographs can be limited in their ability to accurately assess fusion, particularly in complex three-dimensional joints like the first tarsometatarsal joint.
- Overlapping bone structures in the midfoot can obscure the fusion site on plain films, making it difficult to determine if solid union has occurred.
- Metallic hardware used during the procedure (screws or plates) can create artifacts that further complicate radiographic interpretation.
- The orientation of the fusion site relative to the X-ray beam can also affect visualization, with suboptimal angles potentially missing gaps or incomplete unions.
- Clinical assessment remains crucial, as patients may demonstrate functional stability and pain-free weight-bearing despite radiographic uncertainty.
- In cases where standard X-rays are inconclusive but clinical suspicion for nonunion exists, advanced imaging such as CT scans may be necessary, as they provide superior visualization of bony architecture and can better determine if true fusion has occurred.
- The timing of imaging is also important, as radiographic evidence of fusion typically lags behind clinical healing by several weeks to months. Other studies, such as those from 2015 2 and 2013 3, also support the idea that radiology may not always accurately detect union after a Lapidus procedure, but the 2020 study 1 provides the most recent and comprehensive evidence on this topic.