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Role of calcaneus in heel pain: Radiological assessment
Foot and Ankle Surgery 12 (2006) 127–131 www.elsevier.com/locate/fas
Role of calcaneus in heel pain: Radiological assessment Mishra D.K.*, Kurup H.V.1, Musthyala S.2, Patro D.K.3 Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Pondicherry 605006, India Received 26 September 2005; received in revised form 27 February 2006; accepted 14 March 2006
Summary Background: Ever since the original historical description of postero-superior heel pain by Haglund in 1927, it has been attributed to footwear and variations in shape and axis of the calcaneus. Radiological indices used in literature to correlate heel pain with calcaneal abnormalities are inconsistent and prone to high intra and inter-observer variability. Methods: We used two new parameters for assessing the correlation between postero-superior heel pain and the calcaneus. Calcaneal body index assesses the shape of the calcaneus and the calcaneal inclination angle assesses the orientation of the calcaneus. We reviewed 117 cases and 72 controls. We measured calcaneal inclination angle, calcaneal body index along with the conventional angles in use in all cases and controls. Results: We have found these measurements to correlate well with symptoms. Both these parameters are not interdependent. The entire calcaneus is taken into consideration, instead of taking a few fixed and inconsistent bony landmarks. The parameters previously described were also used in this study and it was found that these were not statistically associated with postero-superior heel pain. Conclusions: The two new parameters we have proposed in this study although a tedious method, give a holistic and objective assessment of calcaneal shape and inclination. # 2006 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved. Keywords: Calcaneus; Posterior heel pain; Radiological assessment
1. Introduction Haglund [1] described the clinical condition of retrocalcaneal bursitis, which is mostly referred to as Haglund’s disease. Haglund attributed it to shape of the posterosuperior border of the calcaneus and the wearing of rigid low back shoes. Pain in the postero-superior portion of the calcaneus can be produced by retrocalcaneal bursitis, enlargement of the superior bursal prominence of calcaneus, Achilles tendonitis or inflammation of an adventitious bursa between the Achilles tendon and skin. According to the literature, this condition is seen commonly in adolescent females, particularly when they start wearing shoes with restrictive heel counters. Although this condition has been known for so long, there is no clear mandate regarding its * Correspondence to: Sunderland Royal Hospital, Kayll Road, Sunderland SR4 7TP, UK. Tel.: +44 7766025455 E-mail address: [email protected] (D.K. Mishra). 1 Ysbyty Gwynedd, Bangor LL57 2PW, UK. 2 Southport & Omskirk NHS Trust, Southport PR8 9PN, UK. 3 Department of Orthopaedics, JIPMER, Pondicherry 605006, India.
causation. Pavlov et al. [2] attributed this to compression of the distal Achilles tendon and surrounding soft tissue between the calcaneus and posterior shoe counter. Sella et al. [3] attributed symptoms mostly to the retrocalcaneal bursa and its inflammation. Stephens [4] suggested that excessive prominence of bursal projection of the postero-superior corner of calcaneus was the primary pathology. In Taylor’s series [5] ladies’ shoes with narrow heels or with straps across the heel area were the culprits in most cases but he commented that men’s shoes occasionally caused similar problems. A combination of these seems the more likely pathology in Haglund’s disease. The Achilles tendon rubs against the bursal projection of the calcaneus, if the calcaneal inclination is abnormal or bursal projection is abnormally prominent, thus producing symptoms. Studies so far have largely suggested a calcaneal cause. However, it remains unclear whether the calcaneal prominence posterosuperiorly or the alignment of calcaneus to weight bearing axis is responsible. This study investigates the role of calcaneal alignment to the weight bearing axis and assess the shape of the calcaneus in heel pain. We analysed the
1268-7731/$ – see front matter # 2006 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.fas.2006.03.003
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Table 1 The conventional angles Angles
Case
Control
P-value
Philip–Fowler angle (posterior calcaneal angle) 758 3 1 <758 114 71 Mean (S.D.) 58.1 (8.2) 61.7 (6.6)
>0.05
Calcaneal pitch angle Mean (S.D.)
>0.05
20.4 (7.1)
15.31 (6.2)
Combined Philip–Fowler and calcaneal pitch Mean(S.D.) 78.6 (8.5) 77.3 (5.7) Bursal prominence/parallel pitch line (PPL) +ve PPL 68 29 ve PPL 49 43
>0.05
>0.05 <0.025
reliability of existing and popular measurement techniques for assessing the role of the calcaneus as a cause of posterosuperior heel pain. We evaluated the efficacy of our new methods of assessing calcaneal alignment and compared our findings with those existing in the literature (Tables 1–3). The most popular techniques for assessing the calcaneal cause of heel pain are measurement of the prominence of bursal projection as determined by the posterior calcaneal angle of Fowler and Philip [6] and the parallel pitch line of Pavlov et al. [2]. The orientation of the calcaneus was determined relative to the horizontal plane using the Calcaneal pitch angle (Fig. 1), which is formed by the intersection of the base line with the horizontal. The posterior calcaneal angle of Fowler and Philip (Fig. 2) is formed by the intersection of the base line tangent to the anterior tubercle and medial tuberosity with the line tangent to the posterior surface of the bursal projection and the posterior tuberosity. The parallel pitch line (Fig. 3) is +ve or ve depending on whether the postero-superior aspect of the calcaneus projects above the line or below. However these angles have not been shown to be a reliable index in the diagnosis of Haglund’s syndrome [5,7]. Sella et al. [3] found
Fig. 1. Calcaneal pitch angle.
that pre-operative planning and measurement of the angles, to plan the exact osteotomy required, helps in achieving a good outcome. But whether surgical procedures offer a satisfactory outcome is debatable [5].
2. Materials and methods This prospective study involved patients attending our outpatient clinic between June 1998 and May 1999 with complaints of postero-superior heel pain. Exclusion criteria were duration of symptoms less than 6 months, previous
Table 2 Calcaneal inclination angle Calcaneal inclination angle >108 Controls Cases
4 37
58–98 22 46 P-value <0.001
08–48
<08
44 34
2 0
Table 3 Calcaneal body index Calcaneal body Index <1.758 Controls Cases
39 41
1.758–2.58 29 64 P-value <0.05
>2.58 4 12 Fig. 2. Posterior calcaneal angle of Fowler and Philip.
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Fig. 3. Parallel pitch line.
Fig. 5. Calcaneal body index.
injury or surgery to the Achilles tendon or calcaneus, paediatric patients (age <16 years) and seronegative arthritis. Informed consent was obtained from patients and the study was approved by the regional ethics committee. Lateral weight bearing X-ray of foot with the ankle was taken using a standardized technique as this has been shown to be the most appropriate technique by Perlman et al. [8]. Controls were age and sex matched patients who had ankle or foot X-rays for conditions other than heel pain. Similar weight bearing lateral views were obtained in these controls instead of a routine lateral view. X-ray tracing of the calcaneus was done on graph paper. Mid-points were taken
on the Y-axis at every 5 mm distance on X-axis. A straight line connecting the maximum possible mid-points was taken as the calcaneal axis. The angle between this and the horizontal was taken as the calcaneal inclination angle (Fig. 4). Calcaneal body index (Fig. 5) was measured as the ratio of posterior body height to the anterior body height. Posterior body height (a) and anterior body height (b) were measured in Y-axis and their ratio (a/b) calculates the calcaneal body index. The posterior angle of Fowler and Philip and calcaneal pitch angle were also measured at the same time. Statistical tests (Student’s t-test, x2-test) were used to analyze significance of difference in calcaneal inclination angle, calcaneal body index, posterior calcaneal angle, calcaneal pitch angle and combined posterior calcaneal angle and calcaneal pitch between the cases and the controls.
3. Results
Fig. 4. Calcaneal inclination angle.
A total of 117 feet were studied as patients and 72 as controls for this study. Among patients, 59% (46) were females and 41% (32) were males with age range of 16–74 years (mean age 41.8 11.2 years). Thirty-eight patients had bilateral symptoms. None of the patients or controls were using high-heeled footwear which goes with the practice in rural India. Controls were matched with patients for age and sex. Mean calcaneal inclination angle among patients was 7.338 (standard deviation; S.D. 4.348) and was significantly higher (P < 0.001) than controls (mean 3.708, S.D. 3.568). Mean calcaneal body index among patients was 1.97 (S.D. 0.36) and among controls was mean 1.79 (S.D. 0.33), which was significantly lower (P < 0.05) than the patients.
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Posterior calcaneal angle of Philip and Fowler ranged 27– 838 (mean 58.1 8.28) among patients. Controls measured 42–788 (mean 61.7 6.68) and this was significantly not significant (P > 0.05). Only three patients had Philip– Fowler angle 758 and among controls only one was found with a value 758.Calcaneal pitch angle among patients ranged 3–398 (mean 20.4 7.18) and was higher than controls where it ranged 38–378 (mean 15.3 6.28). Combined Philip-Fowler angle and calcaneal pitch angle among patients ranged 50–1108 (mean 78.6 8.58) and among controls it ranged 64–888 (mean 77.3 5.78). These were both found to be statistically insignificant (P > 0.05). Eleven patients and none of the controls had value 908. Bursal projection was measured using parallel pitch line. Bursal projection of the calcaneus was above the parallel pitch line in 68 (58%) cases and 29 (40%) controls. This was found to be significantly (P < 0.025) higher in patients.
4. Discussion Pain in the postero-superior aspect of the heel is a common problem, which has affected mankind for generations. Establishing its cause has always been a challenge for practitioners involved in diagnosis and treatment. Many authors have blamed the calcaneus for its causation and have tried to establish a correlation between heel pain and calcaneal shape and inclination. In attempts to do so, these authors have come out with certain parameters. These are based on the radiological appearance of the calcaneus and depend on various bony landmarks on lateral X-ray of calcaneus. These bony points although fixed, can vary if there is new-bone formation over and around them. We felt that this can lead to high inter and intra-observer variations in measurements. Thus, there can be a difference in the calculation and chances of false positive or false negative cases. The calcaneus can be erroneously designated as culprit and surgery in these patients can only lead to failure. In this study, we have made a more objective assessment. In our technique, the presence or absence of new bone around bony landmarks does not affect measurements. If there is new bone formation, shape and inclination of the calcaneus will change and to assess these changes there has to be a more objective method. We propose that the shape of posterior body of the calcaneus can have bearing on the causation. We measured the calcaneal body index to establish correlation between the shape of the calcaneus and postero-superior heel pain. Another factor is tilt of the calcaneus and we measured the calcaneal inclination angle to assess this. Among the patients, 59% were women and 41% were men. We found this to be in total contrast to earlier findings that postero-superior heel pain is a disease of women [5,6]. Pavlov et al. [2] had equal number of both sexes, but this is too small a study (four in each group) to comment on sexual predominance. Keck and Kelly [9] suggested a male
predominance, but again they examined only 8 feet. Thus, from our study we can conclude that this condition, although slightly more common in women, is not entirely a disease of the fair sex. Among the control population, fifty six percent were women. Postero-superior heel pain has been suggested as a disease of adolescent and young people [5,6]. We found that it affects mostly patients in third to fifth decade. This agrees with Pavlov’s series [2]. Since the days of Haglund, rigid shoes and slippers with posterior strap has been blamed for postero-superior heel pain. In our study, only 10 cases (12.6%) were using any form of footwear on a regular basis. The rest were either bare foot walkers or wearing footwear occasionally. None of the cases or controls wore high-heeled slippers or shoes. Thus, to blame footwear for causation of this condition is wrong. This can very well affect barefooted people. The posterior calcaneal angle of Philip and Fowler ranged from 27–838 (mean 58.1 8.28) among patients and 42–788 (mean 61.7 6.68) among controls. Philip and Fowler [6] in their original study found this angle ranging between 44 and 698 while Keck and Kelly [9] observed it ranging between 70 and 808. Keck and Kelly also reported difficulty in determining the angle accurately because consistent points of reference were difficult to locate. In our series, the mean angle among cases was lower than those among the controls. Similar findings were reported by Pavlov et al. [2]. The above mentioned studies had considerably less number of subjects compared to our study. Considering these points, we can say that posterior calcaneal angle of Philip and Fowler cannot be used reliably to assess the prominence of bursal projection. Calcaneal pitch angle measures inclination of the calcaneus. In our series, there was an insignificant difference between patients and controls. Among cases mean value was 20.4 7.168 and among controls mean value was 15.31 6.238. Pavlov, in their series [2], did not find any significant difference between the control (mean 24.6 9.08) and case (mean 23.2 5.08). Heneghan and Pavlov [10] observed that if there is osseous plantar projection, the pitch angle would increase. As we have already discussed, this parameter depends on bony landmarks that are likely to change during the lifetime of a subject. Hence, this cannot be used to assess accurately or predict postero-superior heel pain in a subject. Stephens [4] noted that the combination of Philip-Fowler angle and calcaneal pitch when greater than 908 correlated with symptoms. In our series, among cases mean value was 78.63 8.518 and among controls 77.32 5.748, only eleven cases had this angle greater than 908. Hence this parameter did not correlate with symptoms in our series. The calcaneal body index, which is a ratio of posterior body height to anterior body height, reflects the size of posterior calcaneal body. We observed that this ratio is significantly higher among the patient population than in controls. This parameter can be considered a better indicator of shape of the posterior calcaneus than just measuring
D.K. Mishra et al. / Foot and Ankle Surgery 12 (2006) 127–131
prominence of bursal projection. We found this method to be more objective and low chances for inter-observer bias. Higher value indicates a taller calcaneus; hence, we can say that postero-superior heel pain is more common among the population having a tall calcaneus. Excision of the posterosuperior corner of the calcaneus for heel pain will correct the calcaneal body index as well and may thereby contribute to relief of symptoms. The calcaneal inclination angle is a true indicator for calcaneal inclination because this takes the true axis of the calcaneus into consideration. Earlier authors have taken two points (bony landmarks) for constructing this angle. We instead took midpoints at various levels and tried to include three or more points for constructing the angle in an attempt to improve the sensitivity of this parameter. A high calcaneal inclination angle can rub against the Achilles tendon near its insertion during the gait and can thus produce symptoms. In our series, calcaneal inclination angle among cases was significantly higher than controls. High angle is associated with a more vertical calcaneus; hence we can say that postero-superior heel pain is more common in a population having a vertically inclined calcaneus. Zadek’s osteotomy done for postero-superior heel pain improves the Calcaneal inclination angle as well. Elevation of shoe heel decreases this angle making the calcaneus more horizontal and helps to relieve symptoms [10]. The posterior calcaneal angle of Fowler and Philip, calcaneal pitch and parallel pitch line apart from using inconsistent bony landmarks have one more thing in common. All of them are dependent on a line connecting the medial tuberosity to the anterior tuberosity. This line is not a fixed line. It can change if there is new bone formation; sometimes it may not be possible to mark these lines with exactness. Our angles assess the calcaneus as a whole. On the basis of our result from this study, we feel that calcaneal inclination angle and calcaneal body index can be used for more objective assessment for establishing the calcaneal cause for postero-superior heel pain. Even though better radiographic techniques such as magnetic resonance imaging are available nowadays, radiographs are still the first investigation requested in most patients; measurement of these angles will help in excluding primary correctable calcaneal pathology at an early stage and serve as a useful guide to further management. The limitation of our study is that we have not investigated the relevance of these angles to surgical
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planning and outcome after surgery. This was because most of our patients were managed conservatively.
5. Conclusions Postero-superior heel pain is slightly more prevalent in women but not entirely a disease of women. This is more common among adults between the third and fifth decades. Currently used radiological indices are not reliable indicators for assessment of postero-superior heel pain because of the inconsistency of bony landmarks. We propose Calcaneal body index and calcaneal inclination angle as more reliable methods for evaluation of this condition. Our method is technically superior to and more reliable than the existing methods.
Conflict of interest statement There are no conflicts of interest.
References [1] Haglund P. Beitrag zur Klinik der Achillesschne. Z Orthop Chir 1927;49:49–58. [2] Pavlov H, Heneghan MA, Hersh A, Goldman AB, Vigorita V. The Haglund syndrome: initial and differential diagnosis. Radiology 1982;144(1):83–8. [3] Sella EJ, Caminear DS, McLarney EA. Haglund’s syndrome. J Foot Ankle Surg 1998;37(2):110–4. [4] Stephens MM. Haglund’s deformity and retrocalcaneal bursitis. Orthop Clin North Am 1994;25(1):41–6. [5] Taylor GJ. Prominence of the calcaneus: is operation justified? J Bone Joint Surg Br 1986;68(3):467–70. [6] Fowler A, Philip JF. Abnormality of calcaneus as a cause of painful heel; its diagnosis and operative treatment. Brit J Surg 1945;32:494–8. [7] Burhenne LJ, Connell DG. Xeroradiography in the diagnosis of the Haglund syndrome. Can Assoc Radiol J 1986;37(3):157–60. [8] Perlman PR, Dubois P, Siskind V. Validating the process of taking lateral foot X-rays. J Am Podiatr Med Assoc 1996;86(7): 317–21. [9] Keck SW, Kelly PJ. Bursitis of the posterior part of the heel; evaluation of surgical treatment of eighteen patients. J Bone Joint Surg Am 1965;47:267–73. [10] Heneghan MA, Pavlov H. The Haglund painful heel syndrome. Experimental investigation of cause and therapeutic implications. Clin Orthop Relat Res 1984;187:228–34.
Role of calcaneus in heel pain: Radiological assessment Mishra D.K.*, Kurup H.V.1, Musthyala S.2, Patro D.K.3 Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Pondicherry 605006, India Received 26 September 2005; received in revised form 27 February 2006; accepted 14 March 2006
Summary Background: Ever since the original historical description of postero-superior heel pain by Haglund in 1927, it has been attributed to footwear and variations in shape and axis of the calcaneus. Radiological indices used in literature to correlate heel pain with calcaneal abnormalities are inconsistent and prone to high intra and inter-observer variability. Methods: We used two new parameters for assessing the correlation between postero-superior heel pain and the calcaneus. Calcaneal body index assesses the shape of the calcaneus and the calcaneal inclination angle assesses the orientation of the calcaneus. We reviewed 117 cases and 72 controls. We measured calcaneal inclination angle, calcaneal body index along with the conventional angles in use in all cases and controls. Results: We have found these measurements to correlate well with symptoms. Both these parameters are not interdependent. The entire calcaneus is taken into consideration, instead of taking a few fixed and inconsistent bony landmarks. The parameters previously described were also used in this study and it was found that these were not statistically associated with postero-superior heel pain. Conclusions: The two new parameters we have proposed in this study although a tedious method, give a holistic and objective assessment of calcaneal shape and inclination. # 2006 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved. Keywords: Calcaneus; Posterior heel pain; Radiological assessment
1. Introduction Haglund [1] described the clinical condition of retrocalcaneal bursitis, which is mostly referred to as Haglund’s disease. Haglund attributed it to shape of the posterosuperior border of the calcaneus and the wearing of rigid low back shoes. Pain in the postero-superior portion of the calcaneus can be produced by retrocalcaneal bursitis, enlargement of the superior bursal prominence of calcaneus, Achilles tendonitis or inflammation of an adventitious bursa between the Achilles tendon and skin. According to the literature, this condition is seen commonly in adolescent females, particularly when they start wearing shoes with restrictive heel counters. Although this condition has been known for so long, there is no clear mandate regarding its * Correspondence to: Sunderland Royal Hospital, Kayll Road, Sunderland SR4 7TP, UK. Tel.: +44 7766025455 E-mail address: [email protected] (D.K. Mishra). 1 Ysbyty Gwynedd, Bangor LL57 2PW, UK. 2 Southport & Omskirk NHS Trust, Southport PR8 9PN, UK. 3 Department of Orthopaedics, JIPMER, Pondicherry 605006, India.
causation. Pavlov et al. [2] attributed this to compression of the distal Achilles tendon and surrounding soft tissue between the calcaneus and posterior shoe counter. Sella et al. [3] attributed symptoms mostly to the retrocalcaneal bursa and its inflammation. Stephens [4] suggested that excessive prominence of bursal projection of the postero-superior corner of calcaneus was the primary pathology. In Taylor’s series [5] ladies’ shoes with narrow heels or with straps across the heel area were the culprits in most cases but he commented that men’s shoes occasionally caused similar problems. A combination of these seems the more likely pathology in Haglund’s disease. The Achilles tendon rubs against the bursal projection of the calcaneus, if the calcaneal inclination is abnormal or bursal projection is abnormally prominent, thus producing symptoms. Studies so far have largely suggested a calcaneal cause. However, it remains unclear whether the calcaneal prominence posterosuperiorly or the alignment of calcaneus to weight bearing axis is responsible. This study investigates the role of calcaneal alignment to the weight bearing axis and assess the shape of the calcaneus in heel pain. We analysed the
1268-7731/$ – see front matter # 2006 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.fas.2006.03.003
128
D.K. Mishra et al. / Foot and Ankle Surgery 12 (2006) 127–131
Table 1 The conventional angles Angles
Case
Control
P-value
Philip–Fowler angle (posterior calcaneal angle) 758 3 1 <758 114 71 Mean (S.D.) 58.1 (8.2) 61.7 (6.6)
>0.05
Calcaneal pitch angle Mean (S.D.)
>0.05
20.4 (7.1)
15.31 (6.2)
Combined Philip–Fowler and calcaneal pitch Mean(S.D.) 78.6 (8.5) 77.3 (5.7) Bursal prominence/parallel pitch line (PPL) +ve PPL 68 29 ve PPL 49 43
>0.05
>0.05 <0.025
reliability of existing and popular measurement techniques for assessing the role of the calcaneus as a cause of posterosuperior heel pain. We evaluated the efficacy of our new methods of assessing calcaneal alignment and compared our findings with those existing in the literature (Tables 1–3). The most popular techniques for assessing the calcaneal cause of heel pain are measurement of the prominence of bursal projection as determined by the posterior calcaneal angle of Fowler and Philip [6] and the parallel pitch line of Pavlov et al. [2]. The orientation of the calcaneus was determined relative to the horizontal plane using the Calcaneal pitch angle (Fig. 1), which is formed by the intersection of the base line with the horizontal. The posterior calcaneal angle of Fowler and Philip (Fig. 2) is formed by the intersection of the base line tangent to the anterior tubercle and medial tuberosity with the line tangent to the posterior surface of the bursal projection and the posterior tuberosity. The parallel pitch line (Fig. 3) is +ve or ve depending on whether the postero-superior aspect of the calcaneus projects above the line or below. However these angles have not been shown to be a reliable index in the diagnosis of Haglund’s syndrome [5,7]. Sella et al. [3] found
Fig. 1. Calcaneal pitch angle.
that pre-operative planning and measurement of the angles, to plan the exact osteotomy required, helps in achieving a good outcome. But whether surgical procedures offer a satisfactory outcome is debatable [5].
2. Materials and methods This prospective study involved patients attending our outpatient clinic between June 1998 and May 1999 with complaints of postero-superior heel pain. Exclusion criteria were duration of symptoms less than 6 months, previous
Table 2 Calcaneal inclination angle Calcaneal inclination angle >108 Controls Cases
4 37
58–98 22 46 P-value <0.001
08–48
<08
44 34
2 0
Table 3 Calcaneal body index Calcaneal body Index <1.758 Controls Cases
39 41
1.758–2.58 29 64 P-value <0.05
>2.58 4 12 Fig. 2. Posterior calcaneal angle of Fowler and Philip.
D.K. Mishra et al. / Foot and Ankle Surgery 12 (2006) 127–131
129
Fig. 3. Parallel pitch line.
Fig. 5. Calcaneal body index.
injury or surgery to the Achilles tendon or calcaneus, paediatric patients (age <16 years) and seronegative arthritis. Informed consent was obtained from patients and the study was approved by the regional ethics committee. Lateral weight bearing X-ray of foot with the ankle was taken using a standardized technique as this has been shown to be the most appropriate technique by Perlman et al. [8]. Controls were age and sex matched patients who had ankle or foot X-rays for conditions other than heel pain. Similar weight bearing lateral views were obtained in these controls instead of a routine lateral view. X-ray tracing of the calcaneus was done on graph paper. Mid-points were taken
on the Y-axis at every 5 mm distance on X-axis. A straight line connecting the maximum possible mid-points was taken as the calcaneal axis. The angle between this and the horizontal was taken as the calcaneal inclination angle (Fig. 4). Calcaneal body index (Fig. 5) was measured as the ratio of posterior body height to the anterior body height. Posterior body height (a) and anterior body height (b) were measured in Y-axis and their ratio (a/b) calculates the calcaneal body index. The posterior angle of Fowler and Philip and calcaneal pitch angle were also measured at the same time. Statistical tests (Student’s t-test, x2-test) were used to analyze significance of difference in calcaneal inclination angle, calcaneal body index, posterior calcaneal angle, calcaneal pitch angle and combined posterior calcaneal angle and calcaneal pitch between the cases and the controls.
3. Results
Fig. 4. Calcaneal inclination angle.
A total of 117 feet were studied as patients and 72 as controls for this study. Among patients, 59% (46) were females and 41% (32) were males with age range of 16–74 years (mean age 41.8 11.2 years). Thirty-eight patients had bilateral symptoms. None of the patients or controls were using high-heeled footwear which goes with the practice in rural India. Controls were matched with patients for age and sex. Mean calcaneal inclination angle among patients was 7.338 (standard deviation; S.D. 4.348) and was significantly higher (P < 0.001) than controls (mean 3.708, S.D. 3.568). Mean calcaneal body index among patients was 1.97 (S.D. 0.36) and among controls was mean 1.79 (S.D. 0.33), which was significantly lower (P < 0.05) than the patients.
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Posterior calcaneal angle of Philip and Fowler ranged 27– 838 (mean 58.1 8.28) among patients. Controls measured 42–788 (mean 61.7 6.68) and this was significantly not significant (P > 0.05). Only three patients had Philip– Fowler angle 758 and among controls only one was found with a value 758.Calcaneal pitch angle among patients ranged 3–398 (mean 20.4 7.18) and was higher than controls where it ranged 38–378 (mean 15.3 6.28). Combined Philip-Fowler angle and calcaneal pitch angle among patients ranged 50–1108 (mean 78.6 8.58) and among controls it ranged 64–888 (mean 77.3 5.78). These were both found to be statistically insignificant (P > 0.05). Eleven patients and none of the controls had value 908. Bursal projection was measured using parallel pitch line. Bursal projection of the calcaneus was above the parallel pitch line in 68 (58%) cases and 29 (40%) controls. This was found to be significantly (P < 0.025) higher in patients.
4. Discussion Pain in the postero-superior aspect of the heel is a common problem, which has affected mankind for generations. Establishing its cause has always been a challenge for practitioners involved in diagnosis and treatment. Many authors have blamed the calcaneus for its causation and have tried to establish a correlation between heel pain and calcaneal shape and inclination. In attempts to do so, these authors have come out with certain parameters. These are based on the radiological appearance of the calcaneus and depend on various bony landmarks on lateral X-ray of calcaneus. These bony points although fixed, can vary if there is new-bone formation over and around them. We felt that this can lead to high inter and intra-observer variations in measurements. Thus, there can be a difference in the calculation and chances of false positive or false negative cases. The calcaneus can be erroneously designated as culprit and surgery in these patients can only lead to failure. In this study, we have made a more objective assessment. In our technique, the presence or absence of new bone around bony landmarks does not affect measurements. If there is new bone formation, shape and inclination of the calcaneus will change and to assess these changes there has to be a more objective method. We propose that the shape of posterior body of the calcaneus can have bearing on the causation. We measured the calcaneal body index to establish correlation between the shape of the calcaneus and postero-superior heel pain. Another factor is tilt of the calcaneus and we measured the calcaneal inclination angle to assess this. Among the patients, 59% were women and 41% were men. We found this to be in total contrast to earlier findings that postero-superior heel pain is a disease of women [5,6]. Pavlov et al. [2] had equal number of both sexes, but this is too small a study (four in each group) to comment on sexual predominance. Keck and Kelly [9] suggested a male
predominance, but again they examined only 8 feet. Thus, from our study we can conclude that this condition, although slightly more common in women, is not entirely a disease of the fair sex. Among the control population, fifty six percent were women. Postero-superior heel pain has been suggested as a disease of adolescent and young people [5,6]. We found that it affects mostly patients in third to fifth decade. This agrees with Pavlov’s series [2]. Since the days of Haglund, rigid shoes and slippers with posterior strap has been blamed for postero-superior heel pain. In our study, only 10 cases (12.6%) were using any form of footwear on a regular basis. The rest were either bare foot walkers or wearing footwear occasionally. None of the cases or controls wore high-heeled slippers or shoes. Thus, to blame footwear for causation of this condition is wrong. This can very well affect barefooted people. The posterior calcaneal angle of Philip and Fowler ranged from 27–838 (mean 58.1 8.28) among patients and 42–788 (mean 61.7 6.68) among controls. Philip and Fowler [6] in their original study found this angle ranging between 44 and 698 while Keck and Kelly [9] observed it ranging between 70 and 808. Keck and Kelly also reported difficulty in determining the angle accurately because consistent points of reference were difficult to locate. In our series, the mean angle among cases was lower than those among the controls. Similar findings were reported by Pavlov et al. [2]. The above mentioned studies had considerably less number of subjects compared to our study. Considering these points, we can say that posterior calcaneal angle of Philip and Fowler cannot be used reliably to assess the prominence of bursal projection. Calcaneal pitch angle measures inclination of the calcaneus. In our series, there was an insignificant difference between patients and controls. Among cases mean value was 20.4 7.168 and among controls mean value was 15.31 6.238. Pavlov, in their series [2], did not find any significant difference between the control (mean 24.6 9.08) and case (mean 23.2 5.08). Heneghan and Pavlov [10] observed that if there is osseous plantar projection, the pitch angle would increase. As we have already discussed, this parameter depends on bony landmarks that are likely to change during the lifetime of a subject. Hence, this cannot be used to assess accurately or predict postero-superior heel pain in a subject. Stephens [4] noted that the combination of Philip-Fowler angle and calcaneal pitch when greater than 908 correlated with symptoms. In our series, among cases mean value was 78.63 8.518 and among controls 77.32 5.748, only eleven cases had this angle greater than 908. Hence this parameter did not correlate with symptoms in our series. The calcaneal body index, which is a ratio of posterior body height to anterior body height, reflects the size of posterior calcaneal body. We observed that this ratio is significantly higher among the patient population than in controls. This parameter can be considered a better indicator of shape of the posterior calcaneus than just measuring
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prominence of bursal projection. We found this method to be more objective and low chances for inter-observer bias. Higher value indicates a taller calcaneus; hence, we can say that postero-superior heel pain is more common among the population having a tall calcaneus. Excision of the posterosuperior corner of the calcaneus for heel pain will correct the calcaneal body index as well and may thereby contribute to relief of symptoms. The calcaneal inclination angle is a true indicator for calcaneal inclination because this takes the true axis of the calcaneus into consideration. Earlier authors have taken two points (bony landmarks) for constructing this angle. We instead took midpoints at various levels and tried to include three or more points for constructing the angle in an attempt to improve the sensitivity of this parameter. A high calcaneal inclination angle can rub against the Achilles tendon near its insertion during the gait and can thus produce symptoms. In our series, calcaneal inclination angle among cases was significantly higher than controls. High angle is associated with a more vertical calcaneus; hence we can say that postero-superior heel pain is more common in a population having a vertically inclined calcaneus. Zadek’s osteotomy done for postero-superior heel pain improves the Calcaneal inclination angle as well. Elevation of shoe heel decreases this angle making the calcaneus more horizontal and helps to relieve symptoms [10]. The posterior calcaneal angle of Fowler and Philip, calcaneal pitch and parallel pitch line apart from using inconsistent bony landmarks have one more thing in common. All of them are dependent on a line connecting the medial tuberosity to the anterior tuberosity. This line is not a fixed line. It can change if there is new bone formation; sometimes it may not be possible to mark these lines with exactness. Our angles assess the calcaneus as a whole. On the basis of our result from this study, we feel that calcaneal inclination angle and calcaneal body index can be used for more objective assessment for establishing the calcaneal cause for postero-superior heel pain. Even though better radiographic techniques such as magnetic resonance imaging are available nowadays, radiographs are still the first investigation requested in most patients; measurement of these angles will help in excluding primary correctable calcaneal pathology at an early stage and serve as a useful guide to further management. The limitation of our study is that we have not investigated the relevance of these angles to surgical
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planning and outcome after surgery. This was because most of our patients were managed conservatively.
5. Conclusions Postero-superior heel pain is slightly more prevalent in women but not entirely a disease of women. This is more common among adults between the third and fifth decades. Currently used radiological indices are not reliable indicators for assessment of postero-superior heel pain because of the inconsistency of bony landmarks. We propose Calcaneal body index and calcaneal inclination angle as more reliable methods for evaluation of this condition. Our method is technically superior to and more reliable than the existing methods.
Conflict of interest statement There are no conflicts of interest.
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