Cartilage Preservation: Can It Maintain Post-Op Dorsiflexion?
The average range of motion was 73 degrees of dorsiflexion (ranging from 52 to 100 degrees) in 50 feet. Two patients had bilateral bunion surgery but only one foot underwent the described procedure. One of these patients had 64 degrees of dorsiflexion in the foot that underwent the procedure and 38 degrees of dorsiflexion in the foot that did not undergo the procedure. The other patient had 68 degrees of dorsiflexion with the procedure and 62 degrees without the procedure.
In addition to the two patients who had bilateral surgery, nine other patients who did not have the procedure were included in the study for comparison. For those who did not have the procedure, the average range of motion was 58 degrees of dorsiflexion, ranging from 38 to 70 degrees.
How Much Dorsiflexion Is Necessary For Gait?
There is debate in the literature when it comes to the amount of dorsiflexion needed for gait. Root, et. al., state that the minimal amount of dorsiflexion necessary is 65 to 75 degrees at the first MPJ.11 A review of the literature by Nawoczenski, et. al., suggests the range of motion needed for gait is 50 to 90 degrees.12 This discrepancy is due to the fact that there is no standard measurement.
One of the inherent flaws in measuring dorsiflexion is the difference of the description of the zero or starting position. The starting position can be in relation to the plantar plane or to the shaft of the first MPJ. In addition, weightbearing measurements are different from those one would take with the patient non-weightbearing. These differences in the starting point and weightbearing measurements make it difficult to compare results from previous studies on first MPJ range of motion. However, when we performed the cartilage preservation technique, the average dorsiflexion measurement was 73 degrees while the average dorsiflexion measurement without the procedure was 58 degrees. This illustrates that the procedure maintains or improves adequate dorsiflexion at the first MPJ.
Nawoczenski, et. al., performed a study that helps validate this cartilage preservation technique.12 This study illustrated that the amount of dorsiflexion needed for gait was 42 degrees and that the average measured amount of dorsiflexion with the subject non-weightbearing was 57 degrees. Non-weightbearing measurements were higher than weightbearing measurements, according to the study. These non-weightbearing measurements had high interclass correlation coefficients with a standard error of measurement value of 2.3 degrees or less.12 Those who did not receive the procedure in our study were below Nawoczenski’s recommendation for normal range of motion of the first MPJ. Those patients who did receive the procedure are well above the described normal range of motion.
Our procedure certainly shows that these patients had an increased range of motion of the first MPJ in comparison to the literature.12 This could be due to a different measuring technique. However, when we measured the nine patients who did not undergo the procedure, we utilized the same measurement technique for those who did receive the procedure. We found a considerable difference in first MPJ motion.
Granted, some flaws of this study are the lack of preoperative measurements, small sample size and making comparisons to different people who could have had more extensive degeneration of the joint surface. However, this study does validate medial dorsal cartilage preservation as a better procedure than shaving the dorsal medial cartilage.
Dr. Mozena is in private practice at the Town Center Foot Clinic in Portland, Ore. He is a Fellow of the American College of Foot and Ankle Surgeons and is board certified in foot and ankle surgery.
Dr. Marshall is a second-year podiatric surgical resident.
Dr. Burks is a Fellow of the American College of Foot and Ankle Surgeons, and is board certified in foot and ankle surgery. Dr. Burks practices in Little Rock, Ark.