Efficacy of Acetic Acid Delivery via
Efficacy of Acetic Acid Delivery via Iontophoresis on Various Anatomical Foot and Ankle Exostoses
Sunil Jeganathan, MD; Sandreka Jones, BA; Josana Joseph, MS, PAC; Dayana Sawh, BA; Gregory Taylor, DPT
STATEMENT OF PURPOSE
Exostoses, the formation of new bone on existing bone, can develop in a variety of anatomical locations.
Increased physical activity, biomechanical abnormalities, or weight gain can cause cumulative stress and may
lead to pathological changes in the tendon and the tendon’s point of insertion. The development of
intratendinous calcifications and exostoses has the potential to create debilitating pain and movement
dysfunction in patients.
IONTOPHORESIS CASE STUDY
The following 3 patients were treated by the same physical therapist over a 12-month period.
A retrospective chart review revealed significant functional improvement among their similar diagnosis.
Comparable information was extracted to determine the efficacy of iontophoresis with acetic acid 4% solution on various anatomical foot exostoses.
Patient A – Dorsal Hallux Exostoses
Patients with posterior heel pain can be difficult to manage. Contrasting the Haglund's deformity, which is
generally a posterior-superior prominence, the "true" retrocalcaneal exostosis includes an intratendinous
component.  In patients where surgical intervention is contraindicated or refused, conservative physical
therapy treatment options are available. However, there is little evidence to differentiate which particular
treatment plan is most efficacious for patients with symptomatic exostoses.
This case study will present a retrospective analysis of the treatment of three physical therapy patients with
symptomatic exostoses in various areas of the foot.
These cases were chosen because of their dramatic improvement in function and consistency in treatment
plan; most notable is the use of acetic acid 4% solution delivered via iontophoresis. The goal of this case study
is to establish a foundation for treatment plan recommendations for patients with symptomatic exostoses
when surgical intervention is not an option.
PMH: A 48-year old female with a 20-year history of cervical and lumbar spine radiculopathy with mild left foot slap and being unable
to run. Arthritic changes at right 1st MTPJ.
HPI: Pain when weight-bearing at left dorsal 1st MTPJ; insidious onset of many years. Patient’s chief complaint is pain with heel raise
and push-up positions. She is unable to wear heels greater than 2 inches, has a mesomorph body type and a healthy and active lifestyle.
Patient is a professional personal trainer.
Patient A – Left Foot AP – Prior to Treatment
Hallux DF: 40 degrees, empty (painful) endfeel reported
Short step length right, mild foot slap left, restricted terminal stance left
18/60 (“Coming up on your toes: unable to do”- 4/4)
Multiple exostoses at left dorsal 1st MTPJ
Patient A – Left Foot AP – Post Treatment
- Improvement in functional capacity as indicated by the FAAM scores.
- Changes noted in calcifications indicating efficacy of iontophoresis with acetic acid.
Negatives: - No significant change in ROM or chronic gait deviation.
- Accurate X-ray comparison made difficult due to varied imaging personnel.
Patient B – Posterior Heel Exostosis
Iontophoresis uses an electric field to deliver drugs transdermally. The
drug penetrates the skin in ionized form. There are two aspects of the
iontophoresis device. The anode which is the drug reservoir that
releases the drug and the cathode that collects the opposite ions. The
drug is transmitted via a charge that is created by the anode and the
cathode repelling charges causing the drug to be delivered into the
PMH: A 55-year old female with history of prescription medicine for anemia and osteoporosis.
Kilfoil et. al reported the use of acetic acid for the treatment of insertional Achilles tendonitis. A 56-year old
male presented to a podiatry clinic with a history of chronic posterior heel pain. Retrocalcaneal exostoses
were visualized on lateral and calcaneal axial radiographs of both heels. The patient was treated with acetic
acid 4% solution via iontophoresis for 2 weeks after manual therapy techniques, ultrasound, ice massage, and
taping failed to cause significant clinical improvement. After the acetic acid treatments there was significant
improvement in functional capacity as noted by the scores of his FAAM. 
FOOT & ANKLE ASSESSMENT MEASURE (FAAM)
The FAAM is a questionnaire designed to assess the impact of a person’s
injury on their basic daily functions and ability for physical activity.
15 descriptions of basic weight-bearing movements can total 60 points.
A higher score indicates difficulty and inability to do a movement.
Costa et. al reported a case study in which a 15 y/o female soccer player was experiencing symptoms of
bilateral plantar heel pain for one year. Radiographs were negative for heel spurs. After two months of being
treated with acetic acid via iontophoresis, ultrasound, taping, and custom orthoses, she reported no
symptoms related to her plantar fasciitis. She underwent iontophoresis treatments at a frequency of 3 times
per week for 2 weeks initially than twice per week thereafter. Subsequently she received pulsed ultrasound
therapy for 8 minutes. Pulsed ultrasound is used to cause local removal of calcium acetate in the blood from
the area and to reduce inflammation.  The primary cause of chronic pain is calcium deposition before it
becomes an osseous construct as result of tissue that is adapting to dysfunction secondary to long term
pathology. In this patient’s case, acetic acid proved to be an efficacious modality in reducing pain with no
visible exostoses on radiographs. 
Hallux DF: 50 degrees, soft-tissue endfeel; no pain reported
Equal step length for short distances, mild foot slap left persists
2/60 (“Coming up on your toes: no difficulty”- 0/4)
Decreased hypertrophic bone at lateral aspect of 1st metatarsal head
More uniformed joint space at 1st metatarsal head
Decreased sclerotic changes at 1st proximal phalanx
Treatment Plan: Physical Therapy - 2 times a week over 5 weeks completed.
- Manual techniques of joint mobilization for improved ankle/hallux ROM – 20 min
- Phonophoresis with diclofenac sodium topical gel 1% at dorsal hallux – 5 min
- Iontophoresis with acetic acid 4% solution; 1.5cc at dorsal 1st MTPJ – 20 min
Physical Therapy & Iontophoresis
Patients who experience recalcitrant pain from conditions such as plantar fasciitis and heel spurs have been
referred to physical therapy for various treatment modalities. Acetic acid delivery by means of iontophoresis
for various exostoses has not been well studied in literature. “With respect to pain generation, current
literature focuses beyond radiographic evidence of pathological calcified or ossified structures and places a
greater emphasis on the physiological events that precedes this process.” 
Acetic acid via iontophoresis has been used to treat calcium related conditions, including calcific tendonitis,
myositis ossificans and calcific bursitis. Iontophoresis works by causing calcium deposits in tissues to
solubilize and are removed by the blood stream. 
acetic acid 4% solution
being applied to
posterior heel spur.
HPI: Acute pain for 2 weeks at left posterior heel into Achilles tendon. No known mechanism of injury. Patient’s chief complaint is being unable to walk
without pain as well as pain with pressure from shoes. Patient is an administrator with a sedentary lifestyle.
Patient B – Left Lateral Heel – Prior to Treatment
Ankle DF with KE: 10 degrees, soft-tissue endfeel, pain reported
Antalgic, short step-length right
51/60 (“Walking 15 minutes: Extreme Difficulty”- 3/4)
Exostosis at left posterior heel, poorly defined Kager’s triangle
Ankle DF with KE: 30 degrees, soft-tissue endfeel, no pain reported
Equal step length for short distances
4/60 (“Walking 15 minutes: No Difficulty”- 0/4)
Changes in exostosis, well-defined Kager’s triangle
Treatment Plan: Physical Therapy - 2 times a week over 5 weeks completed
- Manual techniques of deep-friction massage for decreased tissue adhesions – 20 min
- Phonophoresis with diclofenac sodium topical gel 1% at posterior heel – 5 min
- Iontophoresis with acetic acid 4% solution; 1.5cc at retro calcaneal bursa
– 20 min
- Significant improvement in functional capacity, most notably daily walking tolerance.
- Changes noted in calcifications, indicating efficacy of iontophoresis with acetic acid.
Negatives: - Not clinically significant changes noted in calcifications, questionable effect of acetic
acid on calcification reduction as reason for objective functional improvement.
Patient B – Left Lateral Heel – Post Treatment
ANALYSIS AND DISCUSSION
In reference to chronic heel pain:
“It is important to note that ACFAS guidelines recommend 6 weeks of unresponsive treatment and testing to
include imaging (e.g., radiographs), corticosteroid injections, orthotics, taping, oral anti-inflammatories, and an
unsupervised home program before referral to a physical therapist. In contrast, APTA guidelines do not indicate
a timeline for certain interventions as described in the ACFAS guidelines. Additionally, recommendations for
iontophoresis, manual therapy, and supervised exercise are included in the APTA guidelines without specific
mention in the ACFAS guidelines.” 
This case study has shown that physical therapy intervention and the use of acetic acid 4% solution via
iontophoresis produced clinically significant improvement in these patients. Successful treatment was
determined based on improvement of gait, FAAM score, and pain reduction, leading to a better quality of life.
While radiographically significant changes in calcification were minimal, the dramatic improvement in patients’
symptoms and function cannot be ignored. A larger, controlled study is warranted to determine a standard of
care for patients with this pathology, thus, leading to recommendations on frequency and duration of the
proposed treatment plan. It is also recommended that this course of treatment be implemented as a primary
intervention for patients when surgical intervention is not an option.
Patient C – Styloid Process Exostosis
FOOT & ANKLE ASSESSMENT MEASURE (FAAM)
Activities & Daily Living Subscale
Please answer every question with one response that most clearly describes your
condition within the past week. If the activity in question is limited by something
other than your foot or ankle, mark not applicable (N/A).
Because of your foot & ankle, how much
difficulty do you have with:
Walking on even ground
Walking on even ground without shoes
Walking up hills
Walking down hills
Going up stairs
Going down stairs
Walking on uneven ground
Stepping up and down curbs
Coming up on your toes
Walking 5 minutes or less
Walking approximately 10 minutes
Walking 15 minutes or greater
To Do N/A
Martin, R; Irrgang, J; Burdett, R; Conti, S; Van Swearingen, J: Evidence of Validity for the Foot and
Ankle Ability Measure. Foot and Ankle International. Vol.26, No.11: 968-983, 2005.
Foot and Ankle Ability Measure (FAAM)
PMH: A 65-year old male with a history of Type II Diabetes, arthritic changes in his left ankle.
HPI: Severe and local pain at left lateral mid-foot with weight-bearing. Insidious onset of 1 year, reports of increased swelling with
prolonged weight-bearing. Initially prescribed NSAIDs and physical therapy which relieved symptoms, the patient became independent until
3 months later when previous symptoms returned.
MRI revealed history of peroneous longus and brevis tendon tears and exotosis at left lateral foot styloid process. Patient was again prescribed
NSAIDs and physical therapy but to include acetic acid 4% solution applied via iontophoresis to the site of pain and exotosis during therapy sessions.
The Foot and Ankle Ability Measure scoring
system was first validated in 2005. It is used to
“evaluate changes in self-reported physical
functions for individuals with leg, ankle, and foot
musculoskeletal disorders.” The FAAM
measures pathology and impairment of
Patient C – Left Foot MO – Prior to Treatment
“Evidence of content validity, construct validity,
reliability and responsiveness has been provided
for the FAAM to be used in a population with
general orthopedic conditions, including pain,
sprain and strain, fractures, plantar fasciitis,
bunion and Achilles rupture.” 
Left ankle DF with KE: 10 degrees, soft-tissue endfeel, pain reported
Antalgic at left mid-stance, short step length right
32/60 (“Walking 15 minutes or greater: Extreme Difficulty”- 3/4)
Exostosis at left lateral foot styloid process
Treatment Plan: Physical Therapy – 1 to 2 times a week over 12 weeks; 10 completed
- Manual techniques for improved ankle ROM – 20 min
- Therapeutic exercises for improved ankle strength/mobility
– 10 min
- Phonophoresis with diclofenac sodium gel 1% at peroneal tendons – 5 min
- Iontophoresis with acetic acid 4% solution; 1.5cc at styloid process – 20 min
Positives: - Significant improvement in functional capacity as shown by his FAAM score.
Negatives: - Irregular treatment frequency and inconsistent imaging personnel.
Patient C – Left Foot MO – Post Treatment
Left ankle DF with KE: 25 degrees, soft-tissue endfeel, no pain reported
Equal step length, no deviations for short distances
4/60 (“Walking 15 minutes: No Difficulty”- 0/4)
Changes in exostosis
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