Clinical And Radiographic Anatomy - The Podiatry Institute

CHAPTER I2EVALUATION OF THE, POSTE.RIOR HEEL:Clinical And Radiographic AnatomyCbarles F. Peebles, D.P.M.Pain in the posterior aspect of the heel can occurwith a variety of conditions secondary to amultitude of etiologies. The classic Haglund'sdeformity is the most common diagnosis for pain inthe region of the Achilles tendon insertion, butfurther investigation has revealed a combination ofetiologies for symptoms presenting in this region.The posterior heel is specialized in many respects,and includes specific skin, soft tissue and osseousvariables that must be evaluated individually. Thispaper will discuss the historical perspective regardingthis symptom complex, and provide the basisfor clinical and radiographic evaluation for thedifferential diagnosis of posterior heel pathology.HISTORICAL REYIEWRetrocalcaneal bursitis has been renamed by manyauthors since being introduced into the literatureby Albert and \fhite in the early 1890s as anirritation and possible infection of metastatic originin the region.''' Haglund, in 7928, described theinflammation of the retrocalcaneal bursa andrelated it to a combination of stiff shoes and theosseous prominence at the posterosuperolateralaspect of the calcaneus, which was treated withbursal excision and resection of the prominentregion.3 Surgical correction and treatment waslargely based on resection of the symptomaticregion until Fowler and Phillip, in 7958, providedmeasurements of the calcaneal dimensions with adescription of the constant retrocalcaneal bursa andthe anatomic considerations of the Achilles tendoninsertion in relation to the posterior superior aspectof the calcaneus.l Ruch combined the cadavericmeasurements of Fowler and Phillip with an understandingof foot biomechanics relating the threefoot Vpes predisposed to retrocalcaneal pain,which include rearfoot varus, compensated forefootvalgus, and plantarflexed first ray.5An expanded knowledge of foot pathomechanicsand further study of the variouspresentations began to broaden the possibledeformities presenting with posterior heel pain.Fiamengo discussed the retrocalcaneal step orexostosis with an increased incidence of painfulcalcifications of the Achilles tendon, which Blackand Kanat expanded with an understanding ofdystrophic calcifications.6'7 Other authors discussedperitendinitis and the potential rheumatologicconditions resulting in inflammatory changes to theAchilles tendon insertion and the posteriorcalcaneus. The continued evaluation of pain at theposterior heel has provided and expanded the listof differential diagnosis for retrocalcaneal pain,and allowed a more complete understanding ofthe anatomic and biomechanical considerations ofthis entity.ANATOMY OF THE POSTERIOR HEELSkin and Subcutaneous TissuesAccess to the posterior heel is affected by the softtissue structures covering the calcaneus andAchilles tendon. The relaxed skin tension linescourse transversely with hyperkeratotic tissue oftenappreciated overlying an eminence. As the plantatand posterior skin junction, the fascial strandssecuring the infracalcaneal fat pad to the deepfascia become more pronounced, decreasing themobility of the overlying skin and subcutaneoustissue. The subcutaneous tissue is composed of athin layer of normal areolar adipose tissueproximally with denser interdigitations of fibro-fattytissue as the junction of the infracalcaneal fat padoccurs. The lesser saphenous vein and itstributaries are contained in this layer as they coursewith the sural netwe along the Achilles tendonlaterally and inferiorly to a more midline relationshipat the middle third of the leg. The sensorysupply to the posterior heel is provided superiorlyby the sural, and distally by the lateral calcanealnerves branching from the sural nerve and themedial calcaneaT nerves, branching from the tibialnelve prior to its bifurcation into the lateral andmedial plantar newes.

72 CFIAPTER 12Vascular supply to the posterior aspect of theheel comes from various sources, and has beenthoroughly evaluated in regard to the supply to theAchilles tendon. The vascular supply to theposterior calcaneus comes from an arterial networkcomposed of the calcaneal anastomotic cascadefrom the posterior tlbial artery, peroneal artery,lateral and medial calcaneal arteries and branchesfrom the lateral and medial plantar afieries. Thesevessels are developed in early childhood, andsupply the calcaneal apophysis and provide vascularityto the insertion of the Achilles tendon,plantaris and peritendinous structures.The supply to the superior aspect of theAchilles tendon comes from the muscular branchesto soleus and gastrocnemius and the surroundingperitendinous structures. A tenuous anastomosis ofproximal and distal branches occurs in the "watershed"region 2 cm to 6 cm proximal to theinsertion, resulting in an area of poor vascularity asdescribed by Lagergren and Lindholm.8 The vascularityof this region has been implicated in itsweakening in both chronic and acute conditions,but was shown to be normal in cases of chronicAchilles tendinopathy by Astrom et al.e Their studydid show a decrease in vascularity related to age,which is consistent with the literature in regard toincreasing tendon pathology with increasingmaturity. The vascularity of the posterior heelrequires treating physicians to incorporate efforts toincrease blood flow to this region, and is essentialfor a complete understanding of pathology of theposterior heel and leg.FasciaThe fascial elements of the posterior heel form anadditional stabllizer of the heel and assist theAchilles tendon in resisting dorsiflexion at theankle joint. The superficial aponeurosis envelopsthe triceps surae and insefis into deep fasciaspecializations, the flexor and peroneal retinaculum,at the medial and lateral aspects of the legand ankle. These are intricately attached to thecalcaneus, as ate the medial and lateral expansionof the Achilles tendon insertion, and provideresistance to dorsiflexion even in the absence of anintact Achilles tendon. The deeper aponeuroticfascia serves as a partial origin for the triceps surae,and encompasses the deep flexor musculature aswell as the neurovascular structures containedwithin the flexor retinaculum. The two layers areseparated by adipose tissue contained withinKager's triangle, which is bordered anteriorly bythe deep fascia and by the deeper layer of thesuperficial aponeurosis at the posterior, medial andlateral borders. The fascia provides an essentialstrut which can become involved with inflammatorychanges at its specialized insertion, resulting inpain in the region.Myotendinous ComplexThe triceps surae complex includes the muscles andtendon of the gastrocnemius, soleus and plantariswhich provide a plantarflexory moment at the ankleand subtalar joint, as well as knee flexion due to theorigin of the gastrocnemius from the femur. TheAchilles tendon, formed from the gastrocnemius andsoleus, courses distally, sumounded by paratenon toinsefi into the middle third of the posterior calcaneus,with expansions coursing anteriorly along the medialand lateral calcaneal borders. As the tendon coursesdistally, the fibers externally rotate with variouspatterns of rotation within the fibers, as described byCummins.l0 Variable insertion patterns of theplantaris tendon have also been described at theanteromedial border of the Achilles tendon. Thevariable rotation of the fibers of the Achillestendon can have an effect when dealing with thefulcrum of pull of the tendon over the prominence ofthe calcaneus. The lack of a true synovialsheath surrounding the Achilles tendon results ininflammatory changes Tocahzed to the vascularparatenon or the tendon itself, which may presentwith an acute or chronically painful posterior heeland leg.The Achilles tendon withstands severe forcesin gait, up to 900 kg of force with fast running.Changes in temain, mechanics and shoes increaseforces, potentially resulting in pathologic changeswithin the tendon. The posterior fibers of theAchilles tendon sustain more force due to anincreased lever atm, which results in moredystrophy to these fibers. Pathologic forces resultin inflammation and subsequent degeneration ofthe tendon with deposition of calcifications at thesuperficial fibers of the insertion. Intratendinouscalcifications and tendon degeneration withinflammation can create pain in the insertionalregion of the calcaneus, as well as increase therigidity of the tendon as it courses over thesuperior lateral aspect of the calcaneus, furtherinflaming the retrocalcaneal bursa.

CHAPTER 12 73Two bursa are intimately associated with theAchilles tendon which may provide a source ofirritation and inflammation. The more constant ofthe lwo is the retrocalcaneal bursa, providing asmooth surface to the superior third of theposterior calcaneus as the Achilles tendon coursesposterior to it until its insertion onto the middlethird of the posterior surface (Fig. 1). This regionhas the potential to become inflamed secondary toirritation from the posterosuperior calcaneus on theAchilles tendon. A retro-Achilles bursa is present inapproximately 500/o of patients as an adventitiousbursa, which is often formed and secondarilyinflamed due to shoe irritation. The irritating forceseffecting these bursa can only be evaluated whenan understanding of the adjacent anatomicstructures is appreciated.Osseous StructuresThe posterior aspect of the calcaneus has threemajor anatomic regions all with specific functionsand potential sites of deformity. The inferior thirdis continuous with the plantar aspect of thecalcaneus, and has the fibers of the planlaraponeurosis and continuing fibers from the Achillestendon attached to it. This region and the entirecircumference of the posterior heel has beeninvolved with rheumatologic conditions and issusceptible to traumatically-induced symptoms.The central third of the posterior calcaneus istrapezoidal in shape, and contains the insertion siteof the Achilles tendon with multiple ridges andgrooves noted. A ridge separates the inferior andmiddle thirds, as a retrocalcaneal exostosis orcalcification is often present as a source of pain inthis region. The most superficial fibers of the Achillestendon inserl in this region, allowing resection of theexostosis while leaving the majority of the tendonintact. The insertion extends anteriorly along themedial and laleral borders anastomosing with thedeep fascia, as previously discussed.The superior third of the posterior surface is asmooth triangularly-shaped facet with the apexsuperiorly and contouring anteriorly toward thesuperior surface of the calcaneus. The previouslymentionedretrocalcaneal bursa is present at thissurface to prevent tendon damage against thebone. This aspect of the posterior surface iscommonly the source of pain with Haglund'sdeformity, as the posterosuperior aspect of thecalcaneus or bursal projection is impinged by theAchilles tendon with dorsiflexion.Figure 1.The anatomic relationship of the retrocalcaneal bursa, Achillestendon with insefiion and posterior calcaneus.CLINJ'ICAL EXAMINAIIONThe clinical evaluation necessitates defining thearea of deformity as well as the stftrctures directlyor indirectly impacting the posterior heel.Reviewing the patient's style of shoes and theonset, duration and presentation of retrocalcanealpain narrows potential diagnosis, and can assist inevaluating for rheumatalogic conditions which canproduce enthesiopathies. Inflammation of the skinor bursa overlying a prominence is frequentlyevident with paratendinous swelling commonlyassociated with tendon or bursa pathology. Pain isoften elicited with direct palpation, as well as withdorsiflexion at the ankle joint. A sequentialevaluation of the various anatomic regions isbeneficial in the initial work-up. Mapping of theposterior heel as shown, assists the clinician inlocalizing the source of pathology and producing alist of differential diagnosis (Figs. 2,3).A thorough evaluation of ankle equinus andthe forefoot-to-rearfoot relationship in the sagittaland frontal planes provide the keys to the underlyingetiology. Ruch described rearfoot varus,compensated forefoot valgus, and feet with aplantarflexed first ray as the common causes forHaglund's deformity, with equinus playing a largerole in the development of insertional pathology.5Failure to determine the underlying pathologyprevents the development of a treatment planconsistent with long-term success. An appreciationof the pathologic structures allows the establishmentof multiple differential diagnosis before anyadjunct examinations are performed.

74 CFIAPTER 12Haglund'sDelormityAchilles Tendonitis/PeritendonitisRetrocalcaneal BursitisRheumatologic ConditionsDystrophic CalcitlcationsMedialExoslosisRetrocalcaneal E(ostosisAchilles lnserlionalCalcilicTendonltisHheumatic Conditionslnsertional PathologyExpansion FascitisDltfuse ldiopathicSkeletal HyperostosisMedialRheumatologic ConditionsFigure 2. Clinical cross hatching of the posteriorheel.Figure J. Schematic cross-hatching of the posterior heel withdiffrrential diagnori. based on regionr.RADIOGRAPHIC EVAIUAIIONOnce the area of interest is narrowed on clinicalexam, radiographic studies are helpful in further isolatingand confirming the differential diagnosis. Thelaterul radiograph is most beneficial in evaluatingposterior heel complain[s, with additional viewsbeneficial for specific presentations. The relationshipof the posterior-superior prominence of thecalcaneus to the remainder of the foot has beendiscussed by various authors attempting to describequantitative measurements for pathology. These areoften used more coflunonly in the academic setting,but can assist the physician in determining thespecific site of pathology. The Fowler,phillip angleis the relation of the inferior calcaneus to theposterior calcaneus. Normally it measures 44 to 69degrees with values greater than 75 degreesdesignated by Fowler and Phillip to be abnormal(nig. 4).' Ruch described the influence of thecalcaneal inclination angle in combination with theFowler-Phillip angle on retrocalcaneal parhologywith Vega et al. correlating increased symptoms withvalues gteater than 90 degrees.ilt The relationship ofparallel pitch lines described by Pavlov indicates anincreased prominence, if bone protrudes superior toa line parallel to the plantar calcaneus in line withthe posterior pofiion of the posterior facet of thesubtalar joint.1'zFigure 4. The relationship of (1) the Fowler-Phillip Angle, (2) calcanealinclination ang1e, and (3) the total angle.Christman established that a lateral radiographallows visualization of the posterolateral aspect ofthe calcaneus, with pathology of the medial andmidline posterior calcaneus hidden by thecalcaneal overlap.l3 A calcaneal axial radiograph isused to determine frontal plane culvature withinthe body of the calcaneus. The evaluation ofcalcifications and exostosis are often evident on alateral view, but the ability to determine theirlocation on the posterior surface of the heel arebest undertaken through the use of the modified

CFIAPTER 12 75Figure 6, Modified calcaneal axral radiograph clepicting retrocalcanealexostosis.REFERENCESFigure 5. Positioning of the patient and X-reybeam for modified calcaneal axial radiograph.calcaneal axial view (Figs. 5, 6)." This view is takenwith the patient standing with the ankle dorsiflexedand the heel on the ground, with the tube 90degrees to the plate and angled parallel with theposterior calcaneus. This view provides excellentvisualization of the middle and superior thirds ofthe calcaneus for the evaluation of retrocalcanealand intratendinous calcifications.Further imaging modalities, including CT andMR[, can be beneficial for additional visualizationof calcaneai and Achilles tendon pathology, but areoften adjuncts to a complete initial clinicd, andradiographic evaluation. A laleral radiograph isthe standard for determining the source of thedeformity with additional views performed asnecessary to provide an adjunct to the clinicalevaluation.SUMMARYRetrocalcaneal pain can have many differentetiologies which carr be effectively evaluatedthrough an understanding of the anatomy of theregion and the mechanics of the foot in respect tothis region. A comprehensive understanding of theclinical and radiographic anatomy of the posteriorheel will assist the physician in making appropriateconserwative and surgical decisions when managingpatients with retroc alcaneal symptomatology.1.2.34569.1011.12.1.3.14Albert E: Achillodynia. Vienna MedJ 34t 11,-l'893.'White CS: Retrocalcaneal bursitis. NY Med Journal 98: 263, 1893.Haglund P: Beitrag zur Klinikder Achillessehne. Ascbr OttbopCbir 49:19, 7949.Fowler A, Phillip JF: Abnormaliry of the calcaneus as a cause ofpainful heef its diagnosis and operative treatment. Brit.l Surg32:494-198, 1941.Ruch JA: Haglund's disease. J Am Pocliatry,'lssoc 64(12): 1000-7003, 7974.Fiamen€io SA, $flarren RF, Marshall JL, Vigorita VT, Hersh A:Posterior heel pain associated with a calcaneal step and Achillestendon calcification. Clin Onhop Rel Res 167:203-211, 1982.Black AS, Kanat IO: A review of soft tissue calcifications. /-FoolSurg 24:243-250, 1985.Lagergren C Lindholm A: Vascular distribution on the Achillestendon - an angiographic and microangiographic sl:udy. Acta CbirScand 776:491-495, 19i8.Astrom M. Westlin Nr Blood flow in chronic Achilles tendinopathy.Clin ot'tbop Rel Res 308:166-172,7991.Cummins EJ, Ansofl BJ, Carr B\f ,]N/right RR: The structure of thecalcaneal tendon (of Achilles) in relation to orthopedic slrr€aery'Surgery Gynecology Obstetics 83:707, 7916.Vega MR, Cavolo DJ, Green RNI, Cohen RS: Haglund's deformity.J Am Pod Assoc 74(3')129-135, 1984.Pavlov H, Heneghan M, Hersh A, Goldman AB, Vigorita V: TheHaglund syndrome: initial and differential diagnosis. Diag Radiol143;83-88,1981.Christman RA: Radiographic anatomy of the calcaneus: part II:posterior sLnface. J Am Pod Med Assoc 77(.11): 581-585, 1987.Grossman AB, Cohen R, Hernandez A: Modified calcaneal axialview. JAP\4-A 83{5) :295, 1993.ADDITIONAL REFERENCESAstrom M, Rausing A: Chronic Achilles tendinopathy. Clin Onhop RelRes 31.6:75r-164, 1995,Banks AS: Achilles peritenclinitis. In DiNapoli DR, Vickers NS, edsReconstructiue Surgety of tbe Foot and Leg - Llpdate 9O Tucker,GA: The Podiatry Institute, Inc: 1989: 213-276.Boberg JS: Calcific Achilles tendinitis. In Vickers NS, Miller SJ, MahanKT, Yu GV, Camasta CA. Ruch JA, eds. ReconstructiLe Surgety oftbe Foot and Leg - LtPdate 96 Tucker, GA: The Podiatry Institute,Inc: 1996:36-38.

76 CFIAPTER 12Downey MS: Retrocalcaneal exostectomy with reattachment of tendoachillis. In Camasta CA, Vickers NS, Ruch JA, eds. ReconstntctiueSurgery of tbe Foot and leg - Llpdate 94 Ttcker, GA: podiatryInstitute Publishing: 1994:32-37.Downey MS, Kalish S: Surgical excision and repair of calcifications ofthe tendo achillis. In Ruch JA, Vickers NS, eds. ReconstntctiueSurgery of tbe Foot and leg - Llpdate 92 Ttcker, GA: podiatryInstitute Publishing; 1992:85-88.Draves DJ: Anatomy of tbe louer extremity Baltimore, Md: \7illiams &Wilkins: 1995.Hanft JR, Chang TJ, Lery AI, Rosenblum B, Southerland C, Weil LS:Grand rounds: Haglund's deformity and retrocalcaneal, intrarendinousspurring. J Foot Ankle Sury 35G):362-368, 1g9G.Kumar R, Matasar K, Stansberry S, Madewell JE, Swischuck LE: Thecalcaneus: normal and abnormal. Radiographics 1L(T:4j.5-440,199r.Lawrence SJ, Botte MJ: The sural nerve in the foot and ankle: ananatomic study with clinical and surgical implications. Foot Ankletnt 15(9)490-49+. 199 t.Le TA, Joseph PM: Common exostectomies of the rearfoot. Ctin podMed Sutg 8(3)$ot-623, 1991..Malay DS: Haglund's deformity and posterior heel pain: a retrospectiveanalysis of treatment. In Vickers NS, Miller SJ, Mahan KT, yu GV,Camasta CA, eds. eds. Reconstructiue Surgery of tbe Foot and Leg -Update 97 Tucker, GA: Podiatry Institute publishing:1997 :223-226.Malay DS: Heel Surgery. In McGiamry ED, ed., ConxprebensiueTextbook of Foctt Surgery, 2nd ed. Baltimore, MD: \7illiams &Wilkinsr 1,992440-455.Notad MA, Mittler BE: An investigation of Fowler-phillip's angle indiagnosing Haglund's defonniry. I Am Podiatry Assoc 74(],O): 486-489, 1984.Osher L: Diagnostic radiographic imaging of the adult calcanets. ClinPod Med. Surg 7Q):333-368, 7990.Ruch JA, Chang TJ: Surgical excision of the Haglund's deforrniry. InCamasta CA, Vickers NS, Ruch JA, eds. Reconsttactiue Surgely oltbe Foot and Leg - Llpdate 9J Tucker, GA: podiatry InstirutePublishing: L993: 27 0-27 4.Sarrafian SK: AnatomY of tbe Foot and Ankle: descrtptiue topograpbicfunctional, 2nd ed. Philadelphia, Pa: JB Lippincotr Company:1.993.Scherer PR, Gordon D, Kashanian A, Belvill A: Misdiagnosed recalcitrantheel pain associated with HLA-B27 antigen. J Am Pod MedAss o c 85Q.O) : 538-5 41. 1.995.Smith TF: Calcification of the tendo achillis: dissection and repair. InCamasta CA, Vickers NS, Ruch JA, eds. Reconstrtr.ctiue Surgery oftbe Foot and Leg - tJpdate 93 Tucker, GA: Podiatry InsritutePublishing: 1993 :27 5 -282.