There is a lot of discussion about what amount of achilles tendon tightness is pathological, and what amount should be considered normal. I will not have the ultimate answer, so relax if you were ready to fight me on it (LOL), but I do want to put gait evaluation of tight achilles in the discussion. What are the 5 typical methods of achilles measurement for review? Each measurement will consist of 2 parts: knee straight for gastrocnemius tightness and knee bent for soleus tightness. They include:
- Ankle Joint Dorsiflexion with Subtalar Joint in Neutral (Root methodology) NWB
- Ankle Joint Dorsiflexion with Subtalar Joint in Neutral with fully loading metatarsals (NWB)
- Ankle Joint Dorsiflexion without concern for Subtalar Joint Positioning NWB
- Ankle Joint Dorsiflexion with Subtalar Joint Maximally Supinated NWB
- Ankle Joint Dorsiflexion with Subtalar Joint Neutral weightbearing (Lunge Test) WB
With each one of these examination techniques, there is normal, loose, and tight degrees that their proponents agree on. Whatever technique you use, stick with it as long as you can differentiate whether the tendon is tight, normal, or loose. I can not tell you if these 3 scenarios are 1/3 patients will be tight, 1/3 are patients with normal tension, and 1/3 of the population will be loose, but definitely close. Of course, you will have specific groups that are usually tight (long distance runners), or loose (yoga practitioners). You need a measurement technique that can differentiate the 3 categories of achilles flexibility, and the extremes should definitely be picked up in gait. I know Drs Root and Weed could sense 2-3 degrees of tightness or looseness in gait primarily from one observation (can you guess which one?). I can remember Dr John Weed pointing out an equinus patient to me by the simple timing of heel contact of one foot with heel lift one the other, but I digress.
What are the 6 possible gait findings with equinus? They include:
- Knee Hyperextension (Genu Recurvatum) early in contact phase
- No heel contact at all (Toe Walker)
- Bouncy Gait
- Early Heel Lift
- Out Toed Gait
- Excessive Midstance and Propulsive Phase Pronation
And, there are other causes of each of these, but if we observe it gait, we could examine for the presence of tightness.
Question #1: How does an early heel lift destabilize the metatarsals now in the propulsive phase earlier than normal?
Question #2: When does abnormal pronation occur in a patient with excessively out toed gait, and what is normal out toeing angles?
Mantra to Memorize when you can visualize the Sagittal Plane: Heel Lift occurs slightly before heel contact on the opposite side shown above. A early heel lift (indicating possible equinus) and a delayed heel lift (indicating possible achilles weakness and/or overflexibility) are both causes for concern.
Question #1: By placing the weight on the metatarsals early, before the opposite side is stable, places high demands for the metatarsals to do major lower extremity stability work.
Question #2 Out toe gait causes midstance and propulsive phase pronation, and the normal external angle of gait is 10-15 degrees.
I hope you can see the importance of sagittal plane evaluation (tough to do in office setting unless you really work on it) for equinus compensations of early heel off and genu recurvatum.
Next week I will talk about the muscles to test when we observe certain gait findings.
