Plantar Heel Pain: How To Get Treatment Results

Author(s): 
By Kirk M. Herring, DPM, MS

Heel pain, especially pain associated with the plantar aponeurosis, is one of the most common overuse injuries affecting adults. Approximately 10 percent of runners as well as many other athletes are affected by plantar fasciitis.1 Conservative estimates have suggested more than 2 million Americans annually receive treatment for this condition.1 As common as this injury may be, there is no universally accepted etiology or treatment for this complaint. In addition to having a strong anatomical grasp of the heel (see “A Guide To Key Anatomical Considerations” below), it’s essential to understand the etiology of the heel pain. While there is no precise etiology as of yet, many consider plantar fasciitis to be an overuse injury caused by frequent overloads of the plantar fascia that lead to failure of the “windlass” mechanism. Most frequently, the proximal and central fibers are involved in this overuse injury. Repetitive and excessive tension leads to a syndrome of overuse and the development of micro-tears to the plantar fascia. These forces are best described and understood as a repetitive series of eccentrically generated forces that exceed the resiliency of the plantar fascia. Many other circumstances have been associated with the development of this injury. These include abnormal foot function (excessively flat or high arched feet), limited ankle joint dorsiflexion range of motion, tight or short tendo Achilles and/or triceps surae, weak triceps surae, limb length discrepancies, fat pad atrophy, poor and inappropriate footwear, athletic training errors, prolonged standing on concrete and obesity. What Are The Clinical Findings? Athletes and individuals complaining of plantar fasciitis experience foot pain that is aggravated by walking, standing and other weightbearing activities. Any portion of the plantar fascia may be affected although most patients describe heel and/or plantar arch pain. Typically, they will experience pain with the first steps of the morning and this pain gradually dissipates or “warms up” with activity. This pain cycle may be repeated following any period of inactivity such as sitting. Patients characterize plantar fasciitis as a deep aching or bruising pain, which may present occasional burning, stabbing and throbbing tendencies. A frequently described cyclical pain profile starts with pain being more severe in the morning, becoming gradually subdued by mid-day only to worsen gradually again by afternoon or evening. Pain typically is localized to the anterior inferior and medial aspect of the calcaneus where the plantar fascia originates at the medial calcaneal tubercle. Pain frequently extends distally several centimeters along the more medial fibers of the central portion of the plantar fascia. A zone of fibrous degeneration may develop and results in thickening of the proximal and medial aspect of the plantar fascia. You can often delineate this zone from adjacent normal tissue and it is painful to palpation. One can also detect differences in heel temperature. You may note a greater warmth to the injured limb. Medial to lateral compression of the affected heel is infrequently painful. Gait patterns are frequently antalgic and the patient will often exhibit a limp especially after brief episodes of sitting. What The Diagnostic Images Will Tell You Radiographic images of the affected foot may exhibit a calcaneal spur or enthesophyte. Generally believed to be the result of longstanding tension at the origin of the plantar aponeurosis, the resulting traction spur is slightly deeper. It resides within the fibers of the abductor hallucis origin or even the most medial fibers of the flexor digitorum brevis, which both share their origins to the calcaneus with the plantar fascia. However, this finding is inconsistent. Only 50 percent of those with plantar fasciitis exhibit this finding.6 In addition, 10 to 16 percent of heel spurs are asymptomatic, which precludes an adequate finding and confirmation of plantar fasciitis. An experienced musculoskeletal ultrasonographer can use ultrasound to detect thickening of the proximal plantar fascia and/or decreased echogenicity of the tissues.7, 8 Ultrasonography can provide important diagnostic evidence of plantar fasciitis when the site of pain is not clearly discernable by physical examination.9 Employing bone scintigraphy can help detect a local inflammatory process at the entheses of the plantar fascia.10 Unfortunately, other disease processes will result in increased osteoblastic activity and lead to increased uptake of Tc-99 m-methylene diphosphonate. Be aware that disorders such as calcaneal stress fractures, tumors, seronegative spondyloarthritis and osteomyelitis may lead to abnormal uptake in the subcalcaneal region of the foot. However, when it is done properly, bone scintigraphy can be 77.6 percent sensitive and has a high level of specificity (85.7 percent).9 Magnetic resonance imaging has been widely used to detect changes to both bone and soft tissue associated with plantar fasciitis.11, 12 STIR sequences exhibiting bone marrow edema are considered to be highly predictive for local hyperemia and periostitis consistent with that of plantar fasciitis.13 How To Develop A Clinical Protocol For Success There is no universally accepted manner for treating plantar fasciitis. However, most specialists do agree that, under most circumstances, conservative treatment modalities are successful at resolving this painful overuse injury.14 While many conservative treatment modalities have proved to be useful, no single treatment appears universally successful. Although the reports of successful resolution of plantar fasciitis range widely from 46 to 100 percent, it is clear that current estimates of near 90 percent success mirror estimates previously observed by Scherer and the Biomechanics Graduate Research Group for 1988 and Davis, et. al., when they initiated a conservative treatment plan.15-17 Treatment outcomes improve when one initiates a systematic approach to treating plantar fasciitis at the time of diagnosis. For optimal results, you should consider three clinical objectives: • Phase I: Reduce local inflammatory processes and expedite plantar fascia repair; • Phase II: Re-establish biomechanic function of the foot, plantar fascia and the “windlass mechanism”; and • Phase III: Re-establish appropriate strength, range of motion and tolerance to eccentric loads typical of standing, walking and running. Exploring The Initial Conservative Treatment Options Physical medicine modalities are well known for their benefits and they have been consistently applied in early treatment of plantar fasciitis. Typically, the direct application of ice, ice baths or contrast soaking aid in the local reduction of inflammation and temporarily augment pain management. Electric stimulation may only provide indirect reduction of interstitial inflammation of the plantar fascia. Ultrasound therapy, hot pack systems and deep tissue massage help eliminate inflammation and aid in restoring plantar fascia tensegrity. Generally, these modalities are considered to be valuable adjuncts to a well-organized treatment plan. Various programs of stretching, range of motion and therapeutic exercises can help re-establish foot function and improve tolerance to load. When it is done appropriately, stretching can serve as an important adjunct to the resumption of the plantar fascia’s ability to tolerate eccentric loading forces that typically occur during stance and gait. Wolgin, et. al., have provided evidence that supports the benefit of stretching in reducing pain.18 They showed that up to 71 percent of patients with plantar fasciitis experienced improvement within eight weeks of initiating a stretching program.18 Antiinflammatory modalities, such as ice and ice baths, are often the first line of treatment. Oral NSAIDs have been a mainstay of treatment. While they effectively relieve symptoms, be aware that they frequently fail to promote sustained relief. When inflammation is severe or fails to respond to initial efforts, one may consider corticosteroid injection(s). However, keep in mind that corticosteroid injections impose the risk of aponeurosis rupture secondary to focal collagen tissue necrosis and can result in focal heel fat pad atrophy.19, 20 You could also employ iontophoresis, a delivery system that uses a direct current to enhance the transcutaneous administration of ionizable substances or solutions to subcutaneous tissues. Physicians have used this modality to deliver 0.4% dexamethasone and acetic acid to the origin of the plantar fascia, effectively reducing inflammation and pain. Gudeman, et. al., conducted a double-blinded, placebo-controlled investigation into the short- and long-term benefits of iontophoresis.1 Following six treatments, the dexamethasone group demonstrated more rapid immediate relief from symptoms and greater improvement then the placebo control group. Unfortunately, the benefits of this modality may be short-lived. Researchers detected no difference at the one-month follow-up. What About Shoes, Orthoses And Splinting? Shoes, orthoses, splinting and/or immobilization form the cornerstone for successful functional management of plantar fasciitis.14-19, 21 When you take the overuse nature of plantar fasciitis into account and attempt to re-establish the windlass mechanism of the foot, there is an enhanced potential for success.22 Unfortunately, too little attention has been directed to appropriately managing the shoes worn during treatment for plantar fasciitis. Emphasizing motion control and stability type athletic shoes (that provide a firm heel cup, instep rigidity, longitudinal integrity and a well-integrated shoe upper) can help decrease excess eccentric tissue strain. The shoe also serves as a vital and functional link between an orthotic and the foot. Orthoses have long been considered to be a reliable method for treating plantar fasciitis. Considerable debate has been waged over the benefits of over-the-counter (OTC), prefabricated and prescription foot and/or ankle orthoses.21 Although studies done by McPoil and Cornwall cast some doubt on the use of prescription orthoses in lieu of OTC devices, it is clear that a well thought-out prescription provides obvious benefits.23 Heel cushions, heel cups and aperture pads appear to provide immediate pain relief for many people who have plantar fasciitis.21, 24 This relief is frequently short-lived and requires other treatment modalities for success.24 Neutral position taping and strapping of the foot provides temporary symptomatic relief of pain caused by plantar fasciitis. Although the functional benefits are temporary and likely do not last longer than 10 minutes with exercise, the soft tissue compression and symptomatic relief afforded by the strapping can last for nearly a week.25 Night splinting has proven to be an effective tool in managing persistent plantar fasciitis.26-30 Batt, et. al., examined the effectiveness of treating plantar fasciitis with and without night splinting.27 They found improvement among all participants in 12.5 weeks while control group crossover participants achieved improvement in an average of 13 weeks.27 Approximately 10 percent of the patients in this study failed to respond to either management attempt. However, when Powell, et. al., also applied a crossover study pattern, they observed no significant differences between his control and study groups at four, six or 12 weeks into treatment of plantar fasciitis.28 Key Insights On Shockwave Therapy It has been roughly estimated that 90 percent of plantar fasciitis cases can be resolved with a conservative management program. The remaining 10 percent represent a recalcitrant or chronic form of plantar fasciitis. In the past, these individuals would be offered treatment that included prolonged periods of cast immobilization or surgical release of the plantar aponeurosis or even radiofrequency lesioning, which gained brief attention but never appeared to gain popularity. Recently, however, extracorporeal shock wave therapy (ESWT) has emerged as a noninvasive treatment modality that is gaining popularity and proving itself as an effective alternative to surgical release of the plantar fascia. Those who use ESWT generate and deliver energy pulses (shockwaves) into soft tissue and bone. Low- and mid-energy orthotripsy devices may use electromagnetic or piezoelectric technology to create the necessary shock wave pattern and energy, and can require multiple treatment sessions to achieve satisfactory results. High-energy orthotripsy devices, such as the OssaTron (Healthtronics), apply an electrohydraulic technology to generate the prescribed shock wave and require only one procedure to achieve the intended outcome. High-energy ESWT generally delivers 1,500 – 2,000 18 kV shock waves to the injured plantar fascia. Also worthy of consideration are mid-energy orthotripsy devices such as the Epos Ultra (Dornier MedTech), which can deliver higher shockwave pressure but suffer from a diminishing zone of treatment as energies increase. The mechanism of ESWT action is not fully understood but it is thought to influence pain receptor physiology, initiate neovascularization, stimulate release of growth factors, enhance fibroblast recruitment and modulate the extracellular substrate as the injured tissue restores tensegrity.31, 32 Among a group of 79 patients, researchers treated 85 heels with high-energy ESWT.33 They found that 75.3 percent of the patients became pain-free, 18.8 percent reported significant improvement and there was a 5 percent recurrence rate. Chen, et. al., applied ESWT to 80 subjects suffering from chronic and recalcitrant plantar fasciitis.31 After six months, 59.3 percent were symptom-free and 27.7 percent were significantly improved. Although this technology is relatively new, the initial results of clinical investigations would suggest that success rates for ESWT meet or exceed those reported for surgical intervention.34 Furthermore, high-energy ESWT appears to be more effective at achieving successful resolution of chronic and recalcitrant plantar fasciitis then its lower energy counterparts.35 Final Thoughts Plantar fasciitis is becoming an increasingly common overuse injury suffered by many active adults. Generally considered to be a self-limiting condition, it need not advance to the stage of becoming chronic or recalcitrant when one can implement a well-organized plan for individualized conservative treatment. Treatment protocols must address existing local inflammation, soft tissue adaptive (fibrotic) changes, resumption of normal foot biomechanics and adequately strengthening, stretching and reconditioning of the plantar fascia to accept and tolerate the typical forces and loads of ambulation. When one’s objectives represent the cornerstones for conservative treatment, physicians who treat plantar fasciitis can anticipate success that meets or exceeds the literature reported standard for resolving this painful and disabling overuse injury. In the event of recalcitrant plantar fasciitis, one should consider ESWT and/or other modalities in order to achieve desirable outcomes. Dr. Herring is a Fellow of the American College of Foot and Ankle Orthopedics and Medicine, and the American Academy of Podiatric Sports Medicine. He is a team podiatrist for several college and professional teams, and has a private practice in Spokane, Wash. Editor’s Note: For a related article, see “Reconsider Biomechanical Causes In Heel Pain Cases” in the November 2002 issue. For more information, check out the archives at www.podiatrytoday.com.
 

 

References:

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