How To Address Mechanically-Induced Subcalcaneal Pain

    Given the abundance of articles written about heel pain and plantar fasciitis, practitioners may wonder whether there is anything new to learn. The prevalence of this condition accounts for the amount of press that it gets, both in the medical community and in the news, but are all the articles and studies discussing the same thing? The numerous opinions and conflicting data may indicate that heel pain is more complicated than people realize. Perhaps some variable has been omitted in the research that contributes to the conflicting outcomes.     Many terms are used interchangeably to describe heel pain. These terms include plantar fasciitis, plantar heel pain syndrome, heel bursitis, heel spur syndrome, subcalcaneal pain, chronic plantar heel pain and many others. Are all these terms truly discussing the same condition or are people using plantar fasciitis as a generic term for heel pain from different etiologies? Perhaps this is similar to how chondramalacia patellae became a catchall term for knee pain. Could this be why some patients respond well to your treatment regimen and others do not?

Establishing Clearer Terminology For Heel Pain

    Differentiating heel pain by its etiology is essential to successful treatment but this is not enough. We should establish clear definitions of the standard nomenclature in order to distinguish one type of heel pain from another. This can only help in future discussions, allowing practitioners and researchers to compare “apples to apples” and helping to reduce confusion regarding appropriate treatment choices for your patients. Even the names plantar fasciitis, plantar fascial strain, calcaneal bursitis and heel pain can cause confusion.     In examining the etiology of heel pain, Lemont demonstrated that a histological examination of the most proximal aspect of the plantar fascia in patients who had plantar fasciotomies for symptoms showed no inflammatory cells.1 If there is no inflammation in the plantar fascia, should we call it plantar fasciitis? Shama reported a large prevalence of heel spurs and/or enthesopathies in patients who have no symptoms.2 If most patients with heel spurs do not have heel pain, why refer to heel pain as heel spur syndrome? Plantar heel pain is also called calcaneal bursitis. However, most anatomy texts do not show a bursa on the plantar aspect of the calcaneus.     It should be apparent how these misnomers can cause confusion in discussions, research outcomes and treatment decisions.

Key Insights On Mechanically-Induced Subcalcaneal Pain

    To eliminate confusion when discussing heel pain, we suggest that the symptomatology that comes from a particular pathomechanics and produces a periostitis of the medial tubercle of the calcaneal tuberosity should be referred to as mechanically-induced subcalcaneal pain (MSC pain).     MSC pain is defined by: 1) occurrence on the first step in the morning; 2) pain exacerbated by previous excessive activity; 3) improvement after walking; and 4) pain limited to the plantar area of the calcaneal tuberosity. Lastly, in order for heel pain to be MSC pain, the symptoms should not be related to other systemic seropositive/negative arthropathies or neuropathies, or to specific injury or trauma as determined by the patient history or examination.     One aspect of our definition that we have not described is the particular pathomechanics that result in MSC pain. According to most articles, orthotic therapy can be successful in treating a significant portion of heel pain related to supination of the midtarsal joint and increased tension on the plantar fascia at its insertion. However, a brief summary of the suspected pathomechanics of MSC pain is in order to truly understand the parameters of treatment.     Most practitioners believe that the dominant factor in MSC pain is pronation of the subtalar joint (STJ). However, upon palpation, the subtalar joint is pronated and the plantar fascia does not become taut. Yet when the midtarsal joint (MTJ) is supinated (inversion of the forefoot to rearfoot), the plantar fascia always gets tight. If it were simply pronation of the STJ that produced the mechanical strain on the plantar fascia, shouldn’t all patients with pronated feet develop MSC pain?     In 1991, researchers proposed the theory on the pathomechanics of MSC pain as a result of a clinical outcome study evaluating the effectiveness of custom foot orthoses (CFOs) for “heel spur syndrome.”3 The study authors’ definition of heel spur syndrome closely matches our definition of MSC pain. The initial stage of the study classified each foot to help determine whether certain foot types develop this syndrome. In 133 heels, 63 had a forefoot valgus deformity, 20 had a rigid plantarflexed first ray and 32 had an everted heel in stance. Eighteen heels had none of the above characteristics.     Since 115 of the 133 heels had a deformity that, upon weightbearing, would force the forefoot into a position of inversion on the rearfoot, the researchers theorized that supination (inversion) of the midtarsal joint placed increased tension on the plantar fascia and contributed to the periostitis that occurs in MSC pain.3     This theory was somewhat supported by Kogler’s work over a decade later.4 He found that when one applied a valgus wedge to a foot with a strain gauge in the plantar fascia, the tensile strength on the fascia decreased significantly and to a greater degree than a varus rearfoot or forefoot wedge. A valgus forefoot wedge would have the opposite mechanical effect of inversion or midtarsal joint supination. Since over 86 percent of the feet examined in the original 1991 study had deformities that supinated the midtarsal joint, it might be logical to add a forefoot valgus wedge to pronate the midtarsal joint.3     The authors from the 1991 study postulated that this inversion of the forefoot due to a valgus heel (everted) or a valgus forefoot is “the primary biomechanical fault or primary etiology” in mechanically-induced heel pain.

When There Are Mixed Results: Could An Ill-Defined Etiology Be The Reason?

    What if the heel pain is not related to midtarsal joint complication? What other pathologies can mimic MSC pain? Would these problems be positively affected by orthotic therapy? What if some of the researchers who investigated orthotic therapy allowed some of the other pathologies to sneak into their patient population? Our definition for MSC pain requires that the symptoms not be related to other systemic seropositive/seronegative arthropathies or neuropathies as determined by the patient history or examination. There is a long list of differential diagnoses, some published and some assumed, that could produce heel pain similar to MSC pain.     Investigation into the etiology of heel symptoms is necessary to establish a treatment plan that will be effective. How many times have we dispensed custom foot orthoses that control the excessive motion of the midtarsal joint but do not relieve symptoms? We propose that many of these failures are attributed to disorders that mimic MSC pain but are not pathomechanical in nature.     A critical investigation into the differentials that also cause heel pain is appropriate before one jumps to the conclusion that the heel pain symptoms are related to mechanical causes and that one can treat this with custom foot orthoses. Indeed, there is a variety of disorders that produce heel pain unrelated to pathomechanics of the foot (see “A Guide To Heel Pain Etiologies Unrelated To Foot Pathomechanics” below). The scope of this list may shed some light on why orthotic therapy can fail when one attempts to treat heel pain generically.     Articles published in the past year on non-surgical treatment of plantar heel pain include: treatment with a pneumatic compression device; tissue-specific stretching of the plantar fascia versus Achilles tendon stretching programs; the role of hamstring tightness on the duration of forefoot loading; the effects of topical wheatgrass cream; the effectiveness of low-Dye taping in the short-term management of plantar fasciitis; comparison of taping and/or stretching combined with different injections; and the ever popular latest trend of extracorporeal shockwave therapy.5-10     All these studies demonstrated variable success with heel pain treatment and this perhaps may be due to a poorly defined etiology for the heel pain patients included in these studies.

What Two Studies Reveal About Orthotics For Plantar Fasciitis

    Within the last year, two randomized prospective studies specifically examined the effectiveness of foot orthotic treatment for “plantar fasciitis.”11,12 Both studies included patients who experienced heel pain for at least four weeks. Roos stated the median duration of heel pain prior to beginning the study was 4.2 (range one to 240) months with 74 percent of patients having symptoms for more than three months.11     Why is this significant? Previous studies have discussed that heel pain tends to respond better in the acute phase rather than the chronic phase. How long must a patient suffer from heel pain to be considered chronic? If some patients in these studies were “chronic,” this could have been a factor in the success of their treatment.

What conclusions can we draw from these two studies?

     Both studies showed improvements in pain and function by treating “plantar fasciitis” patients with orthotics. Landorf excluded any patients with a specific injury or trauma that may have influenced heel pain.12 This distinction better meets our definition of MSC pain. Both of these studies validate that mechanical treatment (orthoses) can bring about positive outcomes in the treatment of “heel pain” and likely indicate that there was a mechanical origin for those patients.11,12 Though it is still unclear what the ideal orthotic would be for these patients, the authors of these studies felt that previous studies supported STJ and MTJ neutral, non-weightbearing casting for custom orthoses.

A Guide To Orthotic Treatment For MSC Pain

    Based on this review and our definition of MSC pain, what should the criteria be for orthotic therapy treatment?     Ensure an accurate diagnosis. Treating a patient who had a seronegative arthopathy and heel pain with an orthotic has little chance of success. Treating a patient with MSC pain that is confirmed by history and examination can have an 86 percent chance of success, based on one outcomes study.3 Eliminate the imitators before utilizing shotgun therapy with generic orthotics or use a prefabricated orthotic to confirm that positional change does relieve some symptoms.     Cast the patient with the midtarsal joint fully pronated. If one casts the foot with the forefoot inverted to the rearfoot, the resulting fabricated orthotic will probably hold the foot in this position, maintaining the tension on the plantar fascia and the periosteum at its attachment.     Make an orthotic that addresses the foot type. Use a medial skive technique for an everted heel foot type and forefoot valgus extensions for an everted forefoot type. These techniques tend to offload the medial column and decrease strain on the plantar fascia.     Remember that attempting to neutralize pronation of the foot by utilizing a forefoot varus wedge only increases the supination of the midtarsal joint and increases strain on the plantar fascia.

In Conclusion

    There is an abundance of information in the literature on heel pain. However, there is still much to learn. A clear definition of the etiology of heel pain and the inclusion/exclusion criteria for the patient population are essential for any future research studies in this area. This will help provide practitioners with the information necessary for improved outcomes.     Ensuring an accurate diagnosis for heel pain should make a difference in the treatment protocol and can improve patient outcomes and satisfaction.     Dr. Scherer is the Chairman of the Department of Applied Biomechanics at the California School of Podiatric Medicine at Samuel Merritt College. He is also the CEO of ProLab Orthotics in Napa, Calif.     Ms. Waters is the Coordinator of Medical Education for ProLab Orthotics. She is a past Clinical Educator for Aircast, Inc. She is also a member of the board for the Prescription Foot Orthotic Laboratory Association (PFOLA). References 1. Lemont H, Ammirati K, Usen N: Plantar fasciitis: A degenerative process without inflammation: JAPMA 93:234-237, 2003. 2. Shama SS, Kominsky SJ, Lemont H: Prevalence of non-painful heel spur and its relationship to postural foot position. JAPMA 73:122, 1983. 3. Scherer PR et al: Heel spur syndrome, pathomechanics and non-surgical treatment. JAPMA 81:68-72,1991 4. Kogler G, Veer FB, Solomonidis SE: The influence of medial and lateral placement of orthotic wedges on loading of the plantar aponeurosis. JBJS 81A: 1403-1413, 1999. 5. Cheung JT et al: Effect of Achilles tendon loading on plantar fascia tension in the standing foot. Clinical Biomechanics (Bristol, Avon) 21(2):194-203, 2006 Feb. 6. Digiovanni BF, et al: Plantar fascia specific stretching exercise improves outcomes in patients with chronic plantar fasciitis. A prospective clinical trial with two-year follow-up: J Bone Joint Surg Am 88(8) 1775-81 2006 Aug. 7. Harty J: The role of hamstring tightness in plantar fasciitis: Foot Ankle Int 26(12) 1089-92, 2005 Dec. 8. Kavros SJ: The efficacy of a pneumatic compression device in the treatment of plantar fasciitis: J Appl Biomech, 21(4)404-13, 2005 Nov 9. Landorf KB Radford JA Keenan Am Redmond AC: Effectiveness of low-Dye taping for the short-term management of plantar fasciitis: JAPMA, 95 525-30, 2005 Nov-Dec. 10. Young MA ,Cook JL Webster KE: The effect of topical wheatgrass cream on chronic plantar fasciitis: a randomized, double blind, placebo-controlled trial. Complement Ther Med 14(1)3-9 2006 Mar. 11. Roos E: Foot orthoses for the treatment of plantar fasciitis: Foot and Ankle Int 166:606-611, June 2006. 12. Langdorf et al. Effectiveness of foot orthoses to treat plantar fasciitis. Arch Intern Med. 166(6):1305-1310, 2006. Additional References 13. Bordelon RL: Subcalcaneal pain. Clin Orthop 177:49,1983 14. Capon, N, Higgs, ER, Dieppe, PA, et al: Arthritis in Behcet’s syndrome. Br J Radiol 56:87,1983 15. Hicks JH: The mechanics of the foot, II. The plantar aponeurosis and the arch. J Anat 88:25,1954 16. Landorf K, Herbert R, Keenan A, Redmond AC: Effectiveness of different types of foot orthoses for the treatment of plantar fasciitis: JAPMA 94:542-549, 2004 17. Lapidus PW, Guidotti FP: Painful heel: report of 323 patients with 364 painful heels. Clin Orthop 39:178, 1965 18. Leach RE, Seavey MS, Salter DK: Results of surgery in athletes with plantar fasciitis. Foot Ankle 7:156,1986 19. Lynch WP, Goforth J, Martin R, Odom R, et al; Conservative treatment of plantar fasciitis, A prospective study, JAPMA 88:375-380, 1998 20. Manter JT: Movements of the subtalar and transverse tarsal joints. Anat Rec 80:397,1951 21. Michetti ML, Jacobs SA: Calcaneal heel spurs: etiology, treatment and a new surgical approach. J Foot Surg 22:234,1983 22. O’Brien D, Martin WJ: A retrospective analysis of heel pain. JAPMA 75:416,1985 23. Riddle DL, Schappert: Volume of ambulatory care visits and patterns of care for patients diagnosed with plantar fasciitis: A national study of medical doctors. Foot and Ankle Int 25: 303-310, 2004 24. Root ML, Orien WP, Weed JH: Normal and Abnormal Function of the Foot, Clinical Biomechanics Corp, Los Angeles, 1977 25. Rosenfeld S: Management of the heel spur (syndrome). JAPMA 75:315, 1985 26. Snook GA, Chrisman OD: The management of subcalcaneal pain. Clin Orthop 82:163,1972 27. Tanz SS: Heel pain. Clin Orthop 28:168,1983 28. Wolgin M, Cook C, Graham C, Mauldin D: Conservative treatment of plantar heel pain and follow-up. Foot Ankle International. 15(3):97-102,1994 For further articles, see “What Are The Best Orthotics For Plantar Fasciitis?” in the December 2001 issue of Podiatry Today or “Conquering Conservative Care For Heel Pain” in the May 2004 issue. Also be sure to visit the archives at www.podiatrytoday.com.
 

References:

CE Exam #147 Choose the single best response to each question listed below. 1) In Lemont’s study of patients who had plantar fasciotomies, histological examination demonstrated which of the following findings? a) No inflammatory cells in the most proximal aspect of the plantar fascia b) A significant presence of inflammation in the lateral aspect of the plantar fascia c) Few inflammatory cells in the lateral aspect of the plantar fascia d) None of the above 2) While some refer to plantar heel pain as calcaneal bursitis, the authors note that anatomy texts do not show an anatomic _______ on the plantar aspect of the calcaneus. a) Inflammation b) Spur c) Bursa d) None of the above 3) Which of the following is a symptom of mechanically-induced subcalcaneal pain (MSC)? a) Increased pain upon walking b) Any symptom closely related to a specific injury or trauma c) Pain exacerbated by previous excessive activity d) All of the above 4) According to most articles, which of the following can be successful in treating a significant portion of heel pain related to supination of the midtarsal joint and increased tension on the plantar fascia at its insertion? a) Extracorporeal shockwave therapy b) Orthotic therapy c) Night splints d) None of the above 5) When it comes to MSC pain, which of the following statements is true? a) Upon palpation, practitioners will note that when the subtalar joint is pronated, the plantar fascia becomes taut. b) When the midtarsal joint is supinated, the plantar fascia always becomes more slack. c) Pronation of the subtalar joint is the dominant factor with MSC pain. d) None of the above 6) When applying a valgus wedge to a foot with a strain gauge in the plantar fascia, Kogler found … a) ... a significant increase of tensile strength on the structure but to a lesser degree than what one might see with a varus rearfoot wedge. b) ... a significant decrease of tensile strength on the structure but to a lesser degree than what one might see with a varus rearfoot wedge. c) ... a significant decrease of tensile strength on the structure and to a greater degree than what one might see with a varus rearfoot wedge. d) None of the above 7) Which of the following potential heel pain etiologies are unrelated to foot pathomechanics? a) Ankylosing spondylitis b) Calcaneal stress fracture c) Paget’s disease d) All of the above 8) True or false: Landorf’s 2006 study of foot orthoses for plantar fasciitis excluded any patients with a specific injury or trauma that may have influenced heel pain. a) True b) False 9) When it comes to treating MSC pain with orthotic therapy, the authors recommend … a) ... using a medial skive technique for an everted heel foot type. b) ... using forefoot valgus extensions for an everted forefoot type. c) A and B d) None of the above Instructions for Submitting Exams Fill out the enclosed card that appears on the following page or fax the form to the NACCME at (610) 560-0502. Within 60 days, you will be advised that you have passed or failed the exam. A score of 70 percent or above will comprise a passing grade. A certificate will be awarded to participants who successfully complete the exam. Responses will be accepted up to 12 months from the publication date.