Cartilage Preservation: Can It Maintain Post-Op Dorsiflexion?

By John Mozena, DPM, PC, and Tyler Marshall, DPM

What Study Results Revealed

   As part of the study, we took a post-op dorsiflexion measurement of the first MPJ with the foot 90 degrees to the leg in neutral position. In order to take these measurements, we grasped the proximal phalanx of the hallux and moved it in maximum dorsiflexion with the goniometer on the hallux and compared it to the declination of the first metatarsal. We recorded the measurements at follow-ups ranging from one to seven months post-op with the average follow-up at four months.    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.

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