Case Study: Treating Chronic Pain In A Middle-Aged Distance Runner

This author discusses the treatment of a 53-year-old runner who presents with a range of podiatric problems as well as right knee pain and chronic low back pain.

   Knee pain and knee injuries in the general population are among the most common musculoskeletal presentations to physicians’ offices each year. About 50 percent of those who regularly exercise will deal with some form of knee pain each year as well.1 Furthermore, as the United States population continues to age, knee arthroscopy and unilateral knee replacements will continue to become more commonplace. Research is beginning to confirm gait and unilateral force aberrations in patients following knee surgery.2-4

   Due to these factors, it is likely that more and more of these patients will seek some sort of non-operative treatment for knee and foot pain, which may spontaneously occur after knee surgery.

   Physical therapy is of great benefit to the pre- and post-surgical patient population. Often when therapy has run its course, patients will continue to suffer. This case study will focus on the use of video and in-shoe pressure gait analysis, along with custom foot orthosis therapy, to assist a middle-aged patient who wished to return to running and regular exercise.

   A 53-year-old Caucasian male presents complaining of right knee pain and chronic low back pain. The patient states that he had an anterior cruciate ligament repair 13 years ago on his right knee. Prior to his chronic knee pain, he was an active runner. The patient is a schoolteacher and is on his feet a lot during the day. He experiences back pain with physical labor so he really decreases the amount of labor he performs. Any increases in walking and running bother him as well so he now uses an elliptical trainer for exercise.

   The patient also complains of some chronic flexion of his right knee. He had seen his orthopedic surgeon recently and received some exercises for his back and to stretch out his knee. Unfortunately, they had no significant benefit. Coincidentally, the patient's son is a runner and was very pleased with the elimination of his knee pain after receiving custom foot orthotics from our office.

Examining The Patient And Making An Assessment

The patient denies any pertinent medical history in the past or present. The musculoskeletal exam reveals that he has an obvious knee flexion on the right with significant knee varus when he walks. He also has a slight early heel lift on the right with maximal pronation at the rearfoot with this early heel lift. The patient exhibits signs of functional hallux limitus and hypermobility, or decreased dorsiflexion stiffness, in the first ray. There is 0 to 5 degrees of dorsiflexion range of motion in both ankle(s). There is no apparent limb length difference on stance even though he has a knee flexion on the right side. This tells me he is probably short 1/8 inch on the left side. The patient does have some quadriceps weakness on the right side. This usually occurs in patients with chronic knee flexion.

   The patient has chronic right knee flexion and genu varum. He also has bilateral functional hallux limitus, bilateral hypermobility of the first ray and bilateral ankle joint equinus. While the patient has no apparent limb length difference, he does have a gait abnormality. The patient also suffers chronic low back pain.

   I explained that the chronic knee flexion is going to cause a problem for him with more pronation in that right foot. His gait is definitely off and this is likely the cause of the chronic low back pain. I suggested that we tape and accommodate him. I gave him information regarding custom orthotics and gait analysis. The patient did well with the taping and on the second visit to the office, we cast him for temporary orthoses and set up a date for his in-office gait analysis.

What The Gait Analysis Reveals

When the patient returned for his gait analysis exam, we took digital video of him utilizing four camera views. We utilized in-shoe pressure analysis in his shoe without orthoses and then with his temporary orthoses in his shoes. We utilized approximately seven separate tests or walking trials with the in-shoe pressure analysis. We made modifications to the orthoses or a unilateral orthosis singularly for each test.

   According to the patient’s first test, the center of pressure on his static in-shoe images was more laterally deviated on the left foot. The patient also had faster accelerations with his right foot. One can often attribute these acceleration differences to a functional or structural short limb (see photo at left). In this case, the chronically flexed right knee may be acting as compensation for an opposite limb length difference.5-6

   This patient’s force versus time curves showed a significant delay or prolongation in his heel curves (see photo at right). This often occurs in patients with an ankle equinus deformity and/or significant pes planus with functional hallux limitus. In this case, the patient has an early heel lift due to his chronic knee flexion. This causes him to load the forefoot very early in stance. This in turn delays the heel unloading of his right foot and causes a disruption in his gait, which often leads to chronic back and limb pain.

How Orthoses Helped The Patient Return To Running Without Pain

We performed six more in-shoe pressure tests and considered orthotic modifications before concluding with an orthosis prescription that we thought was best for the patient. The final prescription consisted of a 3 mm EVA heel lift on both orthoses plus a 1.5 mm PPT™ (Langer Group) heel lift on the patient’s right orthosis.

   The hard heel lifts help to combat the ankle equinus of both feet. The soft heel lift helps to address acceleration issues in the right limb as the patient tended to lift that heel early and accelerate faster on that right side. The soft PPT heel lift seems to act as a dampener, delaying accelerations slightly and often helps to equalize accelerations in asymmetrical limb function.

   I also added a kinetic wedge modification to the patient’s orthoses along with a lateral forefoot wedge on the right device. Both of these modifications assist in driving the foot to load the first metatarsophalangeal joint (MPJ) in late midstance as the heel is lifting. This should assist the function of the plantar fascia.

   The final part of the patient’s prescription consisted of a bilateral medial heel skive modification with a 3 mm metatarsal pad. He also received a digital skive, similar to a Cluffy Wedge™ (Cluffy Biomedical), of 6 mm on the left and 3 mm on the right. The digital skive assists plantar fascia and first ray function as does the metatarsal pad through allowing the first and fifth rays more room to plantarflex during the stance phase. This should lend stability to the midfoot as it begins to load the most in the transition to heel off.

   The final force versus time curves show an elimination of the delays in the heel and forefoot curves (see photo above left). The final static foot images show a more medial center of force progression and more equal pressure distributions as well (see photo on next page).

   The patient returned to the office two weeks after the gait analysis and stated that he was doing great. He said his knee, hip and back felt better. He said his feet felt great as well. Finally, he was able to start running again for the first time in years.

   Dr. Williams is in private practice at Breakthrough Podiatry in Merrillville, Ind. He is a Diplomate of the American Board of Podiatric Surgery. Dr. Williams is also a Past President and Fellow of the American Academy of Podiatric Sports Medicine.

References

1. Olson W. Overuse knee injuries: evaluation and management. Available at https://aapsm.org/ct1100.htm .
2. Milner C. Is gait normal after total knee arthroplasty? Systematic review of the literature. J Orthop Sci. 2009; 14, 114-120.
3. Milner C. Bilateral frontal plane mechanics after unilateral total knee arthroplasty. Arch Phys Med Rehab. 2008; 89(10):1965-69.
4. Butler RJ, Minick KI, Ferber R. Gait mechanics after ACL reconstruction: implications for the early onset of knee osteoarthritis. Br J Sports Med. 2009; 43(5):366-70
5. Gurney B. Leg length discrepancy. Gait Posture. 2002; 15(2):195-206.
6. Walsh M, Connolly P, Jenkinson A, O’Brien T. Leg length discrepancy – an experimental study of compensatory changes in three dimensions using gait analysis. Gait Posture. 2000; 12(2):156-61.