From the Guidelines
X-rays are not reliable for determining nonunion after a Lapidus procedure, and CT or MRI scans are usually more appropriate for this assessment. X-rays have limitations in detecting early stages of nonunion and may not clearly show the fusion status, with studies suggesting that CT scans are more accurate in diagnosing nonunion, especially in complex cases like scaphoid fractures 1. The American College of Radiology recommends using either CT without IV contrast or MRI without IV contrast for evaluating chronic wrist pain, including scaphoid nonunion, as these modalities provide better visualization of bone healing and osteoarthritis compared to X-rays 1.
- Key points to consider when evaluating nonunion after a Lapidus procedure include:
- Clinical evaluation is essential, as persistent pain with weight-bearing or motion at the fusion site may indicate nonunion regardless of imaging findings
- CT scans offer superior visualization of bone healing, with approximately 90-95% accuracy, as they provide detailed cross-sectional images that better demonstrate bony bridging across the fusion site
- Nonunion assessment should occur at least 3-6 months post-surgery, as bone healing in the midfoot can take this long, especially in patients with risk factors like diabetes, smoking, or osteoporosis
- X-rays may detect obvious nonunion signs like persistent joint space, hardware failure, or bone resorption around fixation devices, but they have limitations in detecting early stages of nonunion.
From the Research
Reliability of X-ray in Determining Nonunion after Lapidus Procedure
- The reliability of X-ray in determining nonunion after Lapidus procedure is supported by several studies 2, 3, 4, 5.
- A study published in 2015 found that the union rate of the modified Lapidus procedure was 97.3% (177 of 182 feet) based on radiographic analysis at least 3 months postoperatively 2.
- Another study published in 2007 found that successful union was seen in 14 (82%) of the 17 feet that underwent revision Lapidus arthrodesis, with nonunion documented in 3 (18%) cases based on radiographic evaluation 3.
- A study published in 2014 found that the incidence of nonunion after Lapidus arthrodesis using staple fixation was 3 (8.3%) of 36 feet, with radiographic findings used to determine union 4.
- A study published in 2005 found that there were no cases of nonunion or malunion in 32 patients (38 feet) who underwent the modified Lapidus procedure, with complete radiographic data available for 29 patients (34 feet) 5.
Factors Affecting Nonunion
- Active smoking in the perioperative period was found to be a predictor of nonunion in a study published in 2007 3.
- Meticulous operative technique, rigid internal fixation, and strict postoperative weightbearing restrictions were found to be important factors in achieving successful union and minimizing complications in a study published in 2005 5.
Clinical Relevance
- The modified Lapidus procedure was found to result in a satisfactory clinical outcome in most patients, with 90% of patients satisfied with their foot function and 86% satisfied with the cosmetic appearance of their foot in a study published in 2005 5.
- A study published in 2020 discussed the common complications associated with Lapidus arthrodesis procedures, including nonunion and malunion, and emphasized the importance of proper technique and patient counseling to minimize these complications 6.