The Journal of Foot & Ankle Surgery xxx (2015) 1–7
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Original Research
Classification of Calcaneal Spurs and Their Relationship With Plantar Fasciitis Binghua Zhou, MD, PhD, You Zhou, MD, PhD, Xu Tao, MD, Chengsong Yuan, MD, Kanglai Tang, MD, PhD Department of Orthopedic Surgery, Third Military Medical University Affiliated Southwest Hospital, Chongqing, People’s Republic of China
a r t i c l e i n f o
a b s t r a c t
Keywords: calcaneus classification endoscopic plantar fasciotomy granulocyte count heel pain
Calcaneal spurs, as a cause of plantar fasciitis, are currently debatable. A prospective study was performed to classify calcaneal spurs according to the findings from an investigation of the relationship between calcaneal spurs and plantar fasciitis. Thirty patients with calcaneal spurs and plantar heel pain underwent calcaneal spur removal and endoscopic plantar fasciotomy. The relationship between the classification of calcaneal spurs and plantar fasciitis was evaluated by endoscopic findings, clinical symptoms, radiographic images, and biopsy findings. The visual analog scale for pain and the American Orthopedic Foot and Ankle Society ankle-hindfoot scores for functional evaluation were used preoperatively and postoperatively, respectively. The mean followup period was 24 months. Two separate types of calcaneal spurs were recognized. Type A calcaneal spurs were located superior to the plantar fascia insertion, and type B calcaneal spurs were located within the plantar fascia. Magnetic resonance imaging results showed a more severe plantar fasciitis grade in type B calcaneal spurs preoperatively. Histologic examination showed that the numbers of granulocytes per image in type B spurs were significantly increased compared with those in type A spurs. Statistically significant improvements were found in the mean visual analog scale and American Orthopedic Foot and Ankle Society scores and magnetic resonance imaging results in both groups. The amount of change in the visual analog scale score and American Orthopedic Foot and Ankle Society score, the number of granulocytes per image, and calcaneal spur length showed a high association with the classification of the calcaneal spurs. Calcaneal spurs were completely removed and did not recur in any of the patients on radiographic assessment during the follow-up period. Calcaneal spurs can be classified into 2 distinct types that are indicative of the severity of plantar fasciitis. Ó 2015 by the American College of Foot and Ankle Surgeons. All rights reserved.
Level of Clinical Evidence: 3
Plantar heel pain is a common complaint that occurs in approximately 10% of the population (1,2). Typically, patients present with pain on the plantar aspect of the foot at the attachment of the plantar fascia to the medial tubercle of the calcaneal process (1). Plantar fasciitis is one of the most common causes of heel pain (1,3); however, whether calcaneal spurs affect plantar fasciitis has not yet been fully elucidated (4,5). Calcaneal drilling was first described for painful heels with a calcaneal spur in 1974 (6). Barrett and Day (7) first introduced endoscopic plantar fasciotomy for chronic plantar fasciitis or heel pain. El
Financial Disclosure: This research was supported by grants from the National Natural Science Foundation of China (grant 81230040) and the China Scholarship Council has sponsored Dr B. Zhou. No additional external funding was received for the present study. Conflict of Interest: None reported. Binghua Zhou and You Zhou contributed equally to this study. Address correspondence to: Kanglai Tang, MD, PhD, Department of Orthopedic Surgery, Third Military Medical University Affiliated Southwest Hospital, Gaotanyan Street 30, Chongqing 400038 People’s Republic of China. E-mail address: [email protected] (K. Tang).
Shazly and El Beltagy (8) described an endoscopic-assisted calcaneal drilling and spur removal procedure. Treatment of plantar fasciitis has often been difficult because of the poorly understood mechanism underlying this disease. However, little doubt exists that endoscopic procedures have their advantages, including a short hospital stay, smaller wounds, and faster recovery than open surgery (9–12). More evidence has shown that plantar fasciitis should be referred to as fasciosis because of its degenerative rather than inflammatory nature (3). The significance of calcaneal spurs as a cause of plantar fasciitis has received considerable attention (4,5,13,14). A recent anatomic and histologic study showed that calcaneal spurs were manifested by endochondral ossification (13). A weightbearing compressive disturbance with secondary traction has been suggested as an underlying cause of spur growth (13). In addition, lateral heel radiographs have also confirmed a significant association between calcaneal spurs and plantar heel pain (4). Endoscopic plantar fascia release, calcaneal drilling, and calcaneal spur removal had high success and patient satisfaction rates (8), indicating that calcaneal spurs might play a role in most cases of plantar fasciitis. However,
1067-2516/$ - see front matter Ó 2015 by the American College of Foot and Ankle Surgeons. All rights reserved. http://dx.doi.org/10.1053/j.jfas.2014.11.009
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B. Zhou et al. / The Journal of Foot & Ankle Surgery xxx (2015) 1–7
Fig. 1. (A) Lateral heel radiograph from type B calcaneal spurs. Two lines are shown: (a) an oblique line demarcating the calcaneal border and (b) a horizontal line running from the tip of the spur to the calcaneal border. The spur length was defined from the tip to the base of spur, delineated by a line demarcating the calcaneal border. (B) Radiograph taken on the second day postoperatively showing that the calcaneal spur was completely removed.
asymptomatic calcaneal spurs occur in 30% of the examined population (5). Furthermore, we have often observed that some patients with a small calcaneal spur had more serious symptoms but that other patients with large calcaneal spurs had milder complaints. In addition, a previous study showed that patients with more severe symptoms and those with symptoms for >2 years had worse results after endoscopic plantar fascia release (15). We hypothesized that different types of calcaneal spurs exist and that the grade of plantar fasciitis is dependent on its classification. Therefore, we performed a prospective study to classify the calcaneal spurs according to the findings from an investigation of the relationship between calcaneal spurs and plantar fasciitis. We initially identified 2 types of calcaneal spurs on preoperative radiographs. Next, we performed endoscopic plantar fasciotomy and calcaneal spur removal for the patients. Finally, we examined and evaluated the relationship between calcaneal spur type and each of the following: magnetic resonance imaging (MRI) results, preoperative and postoperative visual analog scale (VAS) and American Orthopedic Foot and Ankle Society (AOFAS) scores, endoscopic findings, and biopsy. Patients and Methods
single observer (B.H.Z.) measured the actual spur length on a radiograph that had not been magnified or decreased from its true size; this was confirmed using the picture archiving and communication systems software (INFINITT, INFINITT Co., Shanghai, China). In brief, 2 lines were delineated on the weightbearing lateral heel radiograph: first, a line demarcating the calcaneal border; and second, a horizontal line from the tip of the spur to the calcaneal border. The spur length was defined from the tip to the base of the spur, as defined by a line demarcating the calcaneal border (Fig. 1A). The plantar fasciitis severity was divided into 3 grades subjectively by 1 of us (B.H.Z.) according to the MRI findings. The grade for plantar fasciitis was recorded according to the ratio between the edema width and the entire width of the plantar fascia on selected oblique sagittal images: grade I, if the ratio was less than one third; grade II, if the ratio was between one and two thirds; and grade III, if the ratio was greater than two thirds (17,18).
Operative Technique The patient was positioned supine with a bolster under the contralateral hip to facilitate external rotation of the operated extremity. Routine intravenous prophylactic antibiotics (cefazolin, 0.5 g) were administered 30 minutes preoperatively by the anesthesiologist. A pneumatic tourniquet applied to the thigh was routinely used with a pressure of 270 mm Hg. Two medial portals were marked preoperatively. Portal A was located at the point of intersection between 2 lines. Line A was a vertical line along the posterior edge of the medial malleolus and line B was a horizontal line running transversely at the junction between the plantar and dorsal skin of the foot. Portal B was 1.5 to 2 cm away from portal A along line B distally (Fig. 2). The incision was made
The ethics committee of the Third Military Medical University Affiliated Southwest Hospital (Chongqing, People’s Republic of China) approved the present study, and the participants provided written informed consent. From January 2009 to March 2012, the senior author (K.L.T.) performed an endoscopic calcaneal spur removal and plantar fasciotomy procedure in 30 patients (38 feet in total). All participants has been diagnosed with calcaneal spurs (M77.31 and M77.32, international classification of disease [ICD] classification system) from the radiographic images, and the presence of plantar heel pain was determined from the patient’s history and physical examination findings. In our conservative treatment protocol, the patients were always encouraged to use a heel pad and plantar fascia stretching exercise before they underwent surgery. In the first month, we prescribed celecoxib (oral, 100 mg/d) to the patients. If the patients still complained of substantial pain, we performed a local corticosteroid injection (compound betamethasone 2 mL, which was comprised of betamethasone diproponate 5 mg and betamethasone sodium phosphate 2 mg) at 2-week intervals for a total of 3 times. All the patients had failed to respond to a trial of conservative treatment for 6 months (16). The participants in the present study were healthy, with unremarkable medical and family histories. Patients were excluded from the study if the heel pain had been caused by any pathologic entities except that of mechanical origin. Eight patients were treated bilaterally on separate occasions at a minimum interval of 3 months postoperatively. All the patients underwent MRI 1 week before surgery. Radiographic Measurements A weightbearing lateral heel radiograph was taken, and computer-aided linear measurements for spur length (mm) were performed, as previously described (4). A
Fig. 2. Line A: a vertical line along the posterior edge of the medial malleolus. Line B: a horizontal line running transversely at the junction between the plantar and dorsal skin of the foot. Portal A was located at the intersection between the 2 lines, lines A and B. Portal B was located 1.5 to 2 cm away from portal A along line B distally.
B. Zhou et al. / The Journal of Foot & Ankle Surgery xxx (2015) 1–7
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Fig. 3. Diagram for the classification of calcaneal spurs. (A) Type A calcaneal spurs: the calcaneal spur is superior to the plantar fascia insertion. (B) Type B calcaneal spurs: the calcaneal spur stretches forward from the point of plantar fascia insertion to within the plantar fascia. The diagram is our original work.
only in the skin with a no. 11 knife blade. Next, mosquito forceps were used to dissect to the deep medial aspect of the plantar fascia. A 2.7-mm 30 endoscope (Smith & Nephew, London, United Kingdom) was introduced from the cannula in portal A. A motorized shaver was introduced from the cannula in portal B to perform the fasciotomy first. Next, one third of the medial band of the plantar fascia was removed until the calcaneal spur was completely exposed. The resected plantar fascia was sent for histologic examination. Next, the location of the calcaneal spur and the severity grade of the plantar fasciitis were determined. Then, an arthroscopic burr from the cannula in portal B was introduced to remove the calcaneal spur, and a radiofrequency transmitter electrode was used to control bleeding. The instrumentation was exchanged between portals A and B to afford better exposure and facilitate excision of the calcaneal spur and a portion of the plantar fascia. The calcaneal spur was completely excised, which was confirmed by intraoperative radiographic inspection. Finally, the cannula was removed, and the skin incision was sutured. The same operative procedure was used for all study patients.
Statistical Analysis For the statistical analysis of the data, paired-sample Student’s t tests were used to compare the preoperative and postoperative VAS and AOFAS scores. Independentsample Student’s t tests were used to assess the calcaneal spur measurements, symptom duration, body mass index, granulocytes per unit area, gender, and age among the groups. Fisher’s exact test was used to compare the MRI grade differences from preoperatively to postoperatively. Spearman’s rank correlation analyses were conducted between the classification of calcaneal spurs and the amount of change in the VAS scores and AOFAS scores, calcaneal spur length, and granulocytes per unit area. Statistical significance was defined as p .05 (5% level). The Statistical Package for Social Sciences for Windows, version 21.0 (SPSS Inc, Chicago, IL) was used for statistical analysis (performed by B.H.Z., Y.Z., and K.L.T.).
Results Postoperative Management All participants received the same postoperative protocol. Bulk dressing and limb elevation were performed for the first 24 hours. Oral celecoxib (100 mg/d) and rest were prescribed for 2 weeks to decrease the postoperative pain and edema. The patients were encouraged to start weightbearing, as tolerated, with the help of a crutch. They were also instructed to perform plantar fascia stretching exercises for 6 weeks from the second postoperative day. The patients performed the stretching exercises under the guidance of a physical therapist. In detail, a towel or strap was used to stretch the bottom of the forefoot, and it was kept in a stretched position for 10 to 20 seconds. The exercise was repeated 3 times, and the aim was to stretch the forefoot 3 times daily. We suggested that the patients wear a soft-soled slipper-like shoe with a heel pad for 6 weeks beginning when they were discharged from the inpatient department at 5 days postoperatively. The patients began to engage in normal weightbearing activities at 6 weeks postoperatively. Plain radiographs were performed on the second day postoperatively. All patients were followed up at 3, 6, 9, and 12 months after surgery and then every 6 months to obtain a VAS score for pain and AOFAS ankle-hindfoot scores for the functional evaluation. Radiographic images, MRI scans, and the VAS scores for patient satisfaction were assessed at 12 months postoperatively. Patient satisfaction was defined as a VAS score for satisfaction >8 (the data were collected by B.H.Z.).
Table 1 Patient baseline demographic characteristics (n ¼ 38 feet in 30 patients) Variable
Type A Spurs (n ¼ 28) Type B Spurs (n ¼ 10) p Value*
Preoperative VAS pain score Preoperative AOFAS score Age (y) Symptom duration (mo) BMI (kg/m2) Male gender
5.7 1.9 60.1 3.8 52.7 3.7 7.1 1.64 20.9 2.8 6 (28.57)
8.3 2.7 55.2 3.6 56.3 6.2 6.3 0.71 22.4 2.6 4 (44.44)
< .001 .24 .31 .19 .17 .55
Abbreviations: AOFAS, American Orthopedic Foot and Ankle Society; BMI, body mass index; VAS, visual analog scale. Data presented as mean standard deviation for continuous numeric data or n (%) for categorical data. * Independent-sample Student’s t test.
We identified 2 types of calcaneal spurs on the preoperative radiographs. Type A spurs were superior to the plantar fascia insertion, and type B spurs stretched forward from the plantar fascia insertion to extend distally within the plantar fascia. These spur configurations are illustrated in Fig. 3. All 30 patients completed a minimum of 12 months of follow-up after surgery, and the mean follow-up duration was 24 (range 12 to 36) months. At 12 months postoperatively, the type A calcaneal spur group included 21 (70.0%) of the 30 patients and 28 (73.68%) of the 38 feet. Of the 21 patients, 15 (71.43%) were female, with a mean average age of 52.7 (range 41 to 71) years. Of the 30 patients and 38 feet, 9 (30.0%) and 10 (26.32%), respectively, were classified as having type B calcaneal spurs. Of the 9 patients, 5 (55.56%) were female, with a mean average age of 56.3 (range 27 to 69) years. We found a statistically significant difference in the preoperative VAS score (p < .001) with respect to type A and B spurs. However, no significant difference could be detected between the type A and type B calcaneal spurs with respect to the BMI (p ¼ .17), symptom duration (p ¼ .19), age (p ¼ .31), gender (p ¼ .55), or the preoperative AOFAS score (p ¼ .24; Table 1). The mean spur length for the type A calcaneal spurs was significantly longer statistically than the mean spur length for type B calcaneal spurs (9.74 1.94 mm versus 5.43 1.78 mm, respectively; p ¼ .004). Postoperative radiographs showed that the calcaneal spurs had been completely removed (Fig. 1B). From the preoperative MRI findings, 18 (64.3%) of the 28 feet with type A calcaneal spurs were defined as grade I, 6 (21%) as grade II, and 4 (14.3%) as grade III. However, the MRI results showed that the ratio of the edema (width) of the plantar fascia in the type B calcaneal spur group was greater (Fig. 4). In the type B calcaneal spur group, 1 (10%) of the 10 feet was defined as grade II and 9 (90%) as grade III (Table 2).
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Fig. 4. (A) Magnetic resonance imaging scan showing a calcaneal spur (red arrow) superior the plantar fascia (yellow arrow) insertion in type A calcaneal spurs. (B) The type B calcaneal spur (red arrow) stretches forward from the plantar fascia insertion (white arrow) and within the plantar fascia.
The MRI scans taken 12 months postoperatively showed that the edema signal in the plantar fascia had disappeared or decreased (Fig. 5). In the type A calcaneal spur group, no plantar fasciitis was found in 7 (25%) of the 28 feet, grade I was found in 19 (67.86%), and grade II was found in 2 (7.14%) However, plantar fasciitis was defined as grade I in 2 (20%) and grade II in 8 (80%) of the 10 feet in the type B calcaneal spur group. The MRI scan analyses showed statistically significant improvement in the grade of plantar fasciitis at 1 year postoperatively in both the type A (p < .001) and type B (p < .001) spur groups (Table 2). The endoscopic findings (Fig. 6) showed that the anatomy of the calcaneal spurs was consistent with the classification made using the preoperative radiographs. Moreover, in terms of the endoscopic findings, more severe plantar fasciitis was observed in those with type B than with type A calcaneal spurs (Fig. 6), consistent with the histologic appearance of the spurs (Fig. 7). Granulocytes per 40 field were significantly enhanced in the type B calcaneal spurs (p ¼ .004). Specifically, the mean number of granulocytes per 40 field in the type A and B spurs was 416 49 and 828 84, respectively. Statistically significant improvements were found in the mean VAS scores postoperatively in both spur groups. The mean VAS score had changed from 5.7 1.9 preoperatively to 1.7 0.3 at 12 months postoperatively in the type A calcaneal spur group (p ¼ .03) and from 8.3 2.7 preoperatively to 2.4 0.4 at 12 months postoperatively in the type B calcaneal spur group (p ¼ .03; Table 3). The AOFAS scores
Table 2 Magnetic resonance imaging grade of plantar fasciitis at 12 months postoperatively in both type A (n ¼ 28 feet) and type B (n ¼ 10 feet) calcaneal spur groups Spur Group
MRI Grade
Preoperatively (n)
12 mo Postoperatively (n)
p Value*
Type A
Normal Mild Moderate Severe Normal Mild Moderate Severe
0 18 (47.37%) 6 (15.79%) 4 (10.53%) 0 0 1 (2.63%) 9 (23.68%)
7 (18.42%) 19 (50%) 2 (5.26%) 0 0 2 (5.26%) 8 (21.05%) 0
< .001
Type B
Abbreviation: MRI, magnetic resonance imaging. * Fisher’s exact test.
< .001
improved from 60.1 3.86 preoperatively to 85.4 5.43 at 12 months postoperatively in the type A calcaneal spur group (p ¼ .04) and from 55.2 3.67 preoperatively to 85.7 7.8 at 12 months postoperatively in the type B calcaneal spur group (p ¼ .02; Table 3). The amount of change in the VAS scores in the type A calcaneal spur group at 12 months postoperatively was a significant decrease compared with changes noted in the type B calcaneal spur group (p < .001). However, the amount of change in the AOFAS scores at 12 months postoperatively showed no significant difference between the 2 groups (p ¼ .21). The correlation analyses showed a correlation coefficient between the classification of calcaneal spurs and the amount of change in the VAS scores, the amount of change in the AOFAS scores, and the calcaneal spur length. The correlation coefficient for the change in VAS score, change in AOFAS score, spur length, and number of granulocytes per unit area (40 magnification field of view) was 0.63, 0.35, 0.86, and 0.95, respectively (Table 4). Two patients (22.2%) reported minimal pain tolerance in the type B calcaneal spur group at 4 months postoperatively. These 2 patients received nonsteroidal anti-inflammatory drugs (celecoxib, 100 mg/d) and heel pad treatment for 2 months. The symptoms had disappeared at 6 months postoperatively. Additionally, 2 other patients (22.2%) complained of persistent anesthesia along the plantar aspect of the hindfoot after walking for long distances. The remaining patients were fully satisfied with their clinical results at the 12-month postoperative follow-up visit. No wound infections developed, and none of the patients was experiencing plantar heel pain at the final follow-up examination.
Discussion The etiology of plantar heel pain is complex and multifactorial. Plantar fasciitis is considered to be the most common pathogenesis of a painful plantar heel (13,19). Plantar fasciitis has been associated with increased intraosseous pressure of the os calcis and the presence of calcaneal spurs (20,21). However, whether inferior calcaneal spurs have a true association with plantar fasciitis has been debated (1,22,23). Our study has shown that calcaneal spurs can be classified into 2 types and that the grade of plantar fasciitis is dependent on the classification of the calcaneal spurs.
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Fig. 5. (A and B) Magnetic resonance imaging scans showing that the affected edema width of the plantar fascia (arrows) had decreased by 12 months postoperatively.
The diagnosis of plantar fasciitis has generally been made clinically, but it can be challenging owing to the complex regional anatomy (24,25). Osborne et al (26) believed that a lateral radiograph should be the first choice for evaluating heel pain, although the key radiologic features that differentiate heel pain included changes in the soft tissues but not spurs. Ehrmann et al (27) reported that increased signal intensity within the plantar fascia with fluid-sensitive sequences was found in plantar fasciitis. Chimutengwende-Gordon et al (28) reported that a significant relationship was observed between the occurrence of night pain and calcaneal marrow edema on MRI studies. In the present study, preoperative radiographs identified 2 types of calcaneal spurs. A smaller ratio of edema width on preoperative MRI scans was found in type A calcaneal spurs compared with type B calcaneal spurs. These MRI findings were consistent with the preoperative VAS scores, indicating that patients had more severe clinical pain with type B spurs than with type A spurs. The endoscopic findings confirmed the difference between the morphology of calcaneal
spurs in the type A and B groups. Therefore, radiographs and MRI could play important roles when forming an accurate diagnosis and classification of calcaneal spurs and plantar fasciitis. Chronic plantar pain has most frequently resulted from of repetitive microtrauma or compression of neurologic structures (29,30). An excessive duration of pronation has been the most common mechanical cause of structural strain resulting in plantar fasciitis (31,32). Forman and Green (33) reported that the intrinsic musculature was the direct cause of biomechanically induced calcaneal spurs. However, asymptomatic calcaneal spurs were present in 10% to 30% of the examined population (19,20). Subcalcaneal spur formation has been suggested to be strongly associated with plantar fasciitis and plantar heel pain (2,15,34). Other alternative mechanisms, including metabolic disturbances, the formation of free radicals, hyperthermia, and genetic factors, have also been linked to degenerative changes (35,36). In the present study, we found that the grade of plantar fasciitis on the postoperative MRI studies, VAS scores (to evaluate pain), and the
Fig. 6. (A and B) Endoscopic findings in type A and B calcaneal spurs. The type A calcaneal spur (red arrow) was located superior to the point of plantar fascia insertion (black arrow). The type B calcaneal spur (red arrow) stretched forward from the point of plantar fascia insertion and was located within and was continuous with the plantar fascia.
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Fig. 7. Hematoxylin-eosin staining (original magnification 40). (A) In type A calcaneal spurs, small diameters of fibroblasts in the plantar fascia were present, with the extracellular matrix in good condition (arrow); organized tissue alignment is present. (B) In type B calcaneal spurs, abundant enlarged inflammatory cells (arrow) were present; the extracellular matrix exhibited significant degradation, with disorganized tissue alignment. We calculated the numbers of granulocytes per unit area. A semiquantification method was implemented in which 3 random images were obtained with a camera attached to a Nikon eclipse microscope (Nikon Instruments Inc, Melville, NY). In each image, the granulocytes were identified manually and analyzed using ImageJ software (National Institutes of Health, Bethesda, MD). Next, the number of granulocytes per image was calculated by averaging the mean values.
AOFAS functional evaluation showed significant improvements in both type A and type B calcaneal spur groups after excision of the calcaneal spurs. These results suggest that the type of calcaneal spurs will correlate with plantar fasciitis severity. In addition, our study has demonstrated that the numbers of granulocytes per field of view, the amount of change in the VAS scores, the amount of change in the AOFAS scores, and calcaneal spur length had a high association with the classification of the calcaneal spurs. Thus, we believe that the classification of the calcaneal spurs will be indicative of plantar fasciitis severity and of the clinical symptoms. However, the determination of a definitive etiology for plantar fasciitis and heel spurs requires additional studies. In the present study, we used 2 medial side portals that were easy to locate. Both portals were far from the tarsal tunnel, and no major complications developed in any of our patients. Endoscopic calcaneal spur excision and partial release of the plantar fascia significantly relieved the pain postoperatively in patients with type A and B calcaneal spurs. El Shazly and El Beltagy (8) performed 3 drill holes from the medial side to the lateral side and excised the spur though the modified metal cannula. In their study, 3 patients reported hyperkeratosis of the scar and 2 reported paresthesia (8). Previous studies have shown that increased intraosseous pressure and vascular congestion of the calcaneus should be considered a part of the pathogenesis of plantar fasciitis and painful heel syndrome (37–39) Endoscopic plantar fasciotomy and inferior calcaneal spur removal might decrease the intraosseous pressure and revascularize congestion of the calcaneus to a certain degree. Collectively, endoscopic plantar fasciotomy and inferior calcaneal spur removal has had a high success rate for both type A and type B calcaneal spurs.
Although both type A and B calcaneal spurs achieved good clinical outcomes postoperatively, the classification is still valuable. First, classification of the spurs will be beneficial for determining both the length of conservative treatment and the timing of surgical treatment. Also, 6 months of conservative treatment might not be needed, because it will not be as beneficial for patients with type B calcaneal spurs. It is possible that we could shorten the conservative treatment to 2 or 3 months and provide surgical options thereafter. Second, classification of spurs can help when anticipating the short-term outcomes postoperatively. Type A calcaneal spurs might realize better outcomes owing to the relatively milder degree of preoperative plantar fasciitis. Also, they might be associated with better recovery after removal of the calcaneal spurs. Finally, the classification of spurs can strengthen our understanding of the etiology of plantar fasciitis and heel pain. The present study had several limitations. First we excluded asymptomatic patients, regardless of the calcaneal spur type, because surgery was not indicated for such patients. Second, the medication (celecoxib) used might have affected the MRI results preoperatively. Third, the AOFAS hindfoot score has been under recent scrutiny with respect to its moderate level of correlation, its satisfactory degree of reliability, and its degree of responsiveness. However, the subjective component of the AOFAS clinical rating scales provides quality-of-life information that conveys acceptable validity regarding the conditions that affect the foot and ankle (40–42). Moreover, we used multiple methods to verify the classification of calcaneal spurs, including MRI, histologic examination, radiography, and self-reported outcomes. Therefore, despite these limitations, the classification of calcaneal spurs was comparatively objective. In conclusion, the results of the present study have demonstrated that calcaneal spurs can be classified into 2 distinct types. Type B
Table 3 Results of VAS score, AOFAS score, and MRI grades of plantar fasciitis at 12 months postoperatively in both type A (n ¼ 28 feet) and type B (n ¼ 10 feet) calcaneal spur groups
Table 4 Association between classification of calcaneal spurs and amount of change in VAS and AOFAS scores from preoperatively to 12 months postoperatively
Variable
Preoperatively
VAS score in type A group VAS score in type B group AOFAS score in type A group AOFAS score in type B group
5.7 8.3 60.1 55.2
1.9 2.7 3.86 3.67
12 mo Postoperatively 1.7 2.4 85.4 85.7
0.3 0.4 5.4 7.8
Variable
Type A (n ¼ 28 spurs)
Change in VAS score Change in AOFAS score Spur length (mm) Granulocytes per MF
4.0 24.86 9.74 416
p Value* .03 .03 .04 .02
Abbreviations: AOFAS, American Orthopedic Foot and Ankle Society; MRI, magnetic resonance imaging; VAS, visual analog scale. Data presented as mean standard deviation. * Paired-sample Student’s t test.
1.3 6.36 1.94 49
Type B (n ¼ 10 spurs) 6.0 29.71 5.43 828
0.5 7.45 1.78 84
Coefficient (r)* 0.63 0.35 0.86 0.95
Abbreviations: AOFAS, American Orthopedic Foot and Ankle Society; MF, magnified (40) field; VAS, visual analog scale. Data presented as mean standard deviation. * Spearman’s r correlation coefficient.
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calcaneal spurs were predisposed to more severe symptoms compared with type A spurs. Endoscopic plantar fasciotomy and inferior calcaneal spur removal had a high success rate for both type A and type B calcaneal spurs. Acknowledgments We thank Journal Prep and Dr. Mark Hardy for their assistance in writing our report. References 1. Irving DB, Cook JL, Menz HB. Factors associated with chronic plantar heel pain: a systematic review. J Sci Med Sport 9:11–22, 2006. 2. McMillan A, Landorf K, Barrett J, Menz H, Bird A. Diagnostic imaging for chronic plantar heel pain: a systematic review and meta-analysis. J Foot Ankle Res 2:32, 2009. 3. Schwartz EN, Su J. Plantar fasciitis: a concise review. Permanente J 18:e105–e107, 2014. 4. Johal K, Milner S. Plantar fasciitis and the calcaneal spur: fact or fiction? Foot Ankle Surg 18:39–41, 2012. 5. Bartold SJ. The plantar fascia as a source of paindbiomechanics, presentation and treatment. J Bodywork Movement Ther 8:214–226, 2004. 6. Hassab H, El-Sherif A. Drilling of the os-calcis for painful heel with calcanean spur. Acta Orthop 45:152–157, 1974. 7. Barrett S, Day S. Endoscopic plantar fasciotomy for chronic plantar fasciitis/heel spur syndrome: surgical techniquedearly clinical results. J Foot Surg 30:568–570, 1990. 8. El Shazly O, El Beltagy A. Endoscopic plantar fascia release, calcaneal drilling and calcaneal spur removal for management of painful heel syndrome. Foot 20:121– 125, 2010. 9. Torudom Y. Plantar fascia release and calcaneal spur excision for sub-calcaneal heel pain. J Med Assoc Thailand 92:S1–S3, 2009. 10. Komatsu F, Takao M, Innami K, Miyamoto W, Matsushita T. Endoscopic surgery for plantar fasciitis: application of a deep-fascial approach. Arthroscopy 27:1105– 1109, 2011. 11. Graviet S, Sinclair G, Kajani N. Ancient schwannoma of the foot. J Foot Ankle Surg 34:46–50, 1995. 12. Hofmeister EP, Elliott MJ, Juliano PJ. Endoscopic plantar fascia release: an anatomical study. Foot Ankle Int 16:719–723, 1995. 13. Smith S, Tinley P, Gilheany M, Grills B, Kingsford A. The inferior calcaneal spurdanatomical and histological considerations. Foot 17:25–31, 2007. 14. Chundru U, Liebeskind A, Seidelmann F, Fogel J, Franklin P, Beltran J. Plantar fasciitis and calcaneal spur formation are associated with abductor digiti minimi atrophy on MRI of the foot. Skeletal Radiol 37:505–510, 2008. 15. Bazaz R, Ferkel RD. Results of endoscopic plantar fascia release. Foot Ankle Int 28:549–556, 2007. 16. Thomas JL, Christensen JC, Kravitz SR, Mendicino RW, Schuberth JM, Vanore JV, R, Baker J. The diagnosis and treatment of heel pain: Weil LS Sr, Zlotoff HJ, Bouche a clinical practice guidelinedrevision 2010. J Foot Ankle Surg 49:S1–S19, 2010. 17. Johnson DP, Wakeley CJ, Watt I. Magnetic resonance imaging of patellar tendonitis. J Bone Joint Surg Br 78:452–457, 1996.
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18. Thomazeau H, Rolland Y, Lucas C, Duval J-M, Langlais F. Atrophy of the supraspinatus belly assessment by MRI in 55 patients with rotator cuff pathology. Acta Orthop 67:264–268, 1996. 19. Weiss E. Calcaneal spurs: examining etiology using prehistoric skeletal remains to understand present day heel pain. Foot 22:125–129, 2012. 20. Tu P, Bytomski JR. Diagnosis of heel pain. Am Fam Physician 84:909–916, 2011. 21. Vyce SD, Addis-Thomas E, Mathews EE, Perez SL. Painful prominences of the heel. Clin Podiatr Med Surg 27:443–462, 2010. 22. Alshami AM, Souvlis T, Coppieters MW. A review of plantar heel pain of neural origin: differential diagnosis and management. Manual Ther 13:103–111, 2008. 23. Hossain M, Makwana N. “Not plantar fasciitis”: the differential diagnosis and management of heel pain syndrome. Orthop Trauma 25:198–206, 2011. 24. Johnson RE, Haas K, Lindow K, Shields R. Plantar fasciitis: what is the diagnosis and treatment. Orthop Nurs 33:198–204, 2014. 25. McNally EG, Shetty S. Plantar fascia: imaging diagnosis and guided treatment. Semin Musculoskelet Radiol 14:334–343, 2010. 26. Osborne H, Breidahl W, Allison G. Critical differences in lateral X-rays with and without a diagnosis of plantar fasciitis. J Sci Med Sport 9:231–237, 2006. 27. Ehrmann C, Maier M, Mengiardi B, Pfirrmann CW, Sutter R. Calcaneal attachment of the plantar fascia: MR findings in asymptomatic volunteers. Radiology 272:807– 814, 2014. 28. Chimutengwende-Gordon M, O’Donnell P, Singh D. Magnetic resonance imaging in plantar heel pain. Foot Ankle Int 31:865–870, 2010. 29. Lareau CR, Sawyer GA, Wang JH, DiGiovanni CW. Plantar and medial heel pain: diagnosis and management. J Am Acad Orthop Surg 22:372–380, 2014. 30. Chen H, Ho H-M, Ying M, Fu SN. Association between plantar fascia vascularity and morphology and foot dysfunction in individuals with chronic plantar fasciitis. J Orthop Sports Phys Ther 43:727–734, 2013. 31. Kwong P, Kay D, Voner R, White M. Plantar fasciitis: mechanics and pathomechanics of treatment. Clin Sports Med 7:119–126, 1988. 32. Kosmahl EM, Kosmahl HE. Painful plantar heel, plantar fasciitis, and calcaneal spur: etiology and treatment. J Orthop Sports Phys Ther 9:17–24, 1987. 33. Forman W, Green M. The role of intrinsic musculature in the formation of inferior calcaneal exostoses. Clin Podiatr Med Surg 7:217–223, 1990. 34. Stecco C, Corradin M, Macchi V, Morra A, Porzionato A, Biz C, De Caro R. Plantar fascia anatomy and its relationship with Achilles tendon and paratenon. J Anat 223:665–676, 2013. 35. Paoloni M, Tavernese E, Ioppolo F, Fini M, Santilli V. Complete remission of plantar fasciitis with a gluten-free diet: relationship or just coincidence. Foot 24:140–142, 2014. 36. Wearing SC, Smeathers JE, Urry SR, Hennig EM, Hills AP. The pathomechanics of plantar fasciitis. Sports Med 36:585–611, 2006. 37. Davies MS, Weiss GA, Saxby TS. Plantar fasciitis: how successful is surgical intervention. Foot Ankle Int 20:803–807, 1999. 38. Daly PJ, Kitaoka HB, Chao EY. Plantar fasciotomy for intractable plantar fasciitis: clinical results and biomechanical evaluation. Foot Ankle Int 13:188–195, 1992. 39. Schepsis AA, Leach RE, Gouyca J. Plantar fasciitis: etiology, treatment, surgical results, and review of the literature. Clin Orthop Relat Res 266:185–196, 1991. 40. Bader L, Park K, Gu Y, O’Malley MJ. Functional outcome of endoscopic plantar fasciotomy. Foot Ankle Int 33:37–43, 2012. 41. Ibrahim T, Beiri A, Azzabi M, Best AJ, Taylor GJ, Menon DK. Reliability and validity of the subjective component of the American Orthopaedic Foot and Ankle Society clinical rating scales. J Foot Ankle Surg 46:65–74, 2007. 42. Kitaoka HB, Alexander IJ, Adelaar RS, Nunley JA, Myerson MS, Sanders M. Clinical rating systems for the ankle-hindfoot, midfoot, hallux, and lesser toes. Foot Ankle Int 15:349–353, 1994.
Contents lists available at ScienceDirect
The Journal of Foot & Ankle Surgery journal homepage: www.jfas.org
Original Research
Classification of Calcaneal Spurs and Their Relationship With Plantar Fasciitis Binghua Zhou, MD, PhD, You Zhou, MD, PhD, Xu Tao, MD, Chengsong Yuan, MD, Kanglai Tang, MD, PhD Department of Orthopedic Surgery, Third Military Medical University Affiliated Southwest Hospital, Chongqing, People’s Republic of China
a r t i c l e i n f o
a b s t r a c t
Keywords: calcaneus classification endoscopic plantar fasciotomy granulocyte count heel pain
Calcaneal spurs, as a cause of plantar fasciitis, are currently debatable. A prospective study was performed to classify calcaneal spurs according to the findings from an investigation of the relationship between calcaneal spurs and plantar fasciitis. Thirty patients with calcaneal spurs and plantar heel pain underwent calcaneal spur removal and endoscopic plantar fasciotomy. The relationship between the classification of calcaneal spurs and plantar fasciitis was evaluated by endoscopic findings, clinical symptoms, radiographic images, and biopsy findings. The visual analog scale for pain and the American Orthopedic Foot and Ankle Society ankle-hindfoot scores for functional evaluation were used preoperatively and postoperatively, respectively. The mean followup period was 24 months. Two separate types of calcaneal spurs were recognized. Type A calcaneal spurs were located superior to the plantar fascia insertion, and type B calcaneal spurs were located within the plantar fascia. Magnetic resonance imaging results showed a more severe plantar fasciitis grade in type B calcaneal spurs preoperatively. Histologic examination showed that the numbers of granulocytes per image in type B spurs were significantly increased compared with those in type A spurs. Statistically significant improvements were found in the mean visual analog scale and American Orthopedic Foot and Ankle Society scores and magnetic resonance imaging results in both groups. The amount of change in the visual analog scale score and American Orthopedic Foot and Ankle Society score, the number of granulocytes per image, and calcaneal spur length showed a high association with the classification of the calcaneal spurs. Calcaneal spurs were completely removed and did not recur in any of the patients on radiographic assessment during the follow-up period. Calcaneal spurs can be classified into 2 distinct types that are indicative of the severity of plantar fasciitis. Ó 2015 by the American College of Foot and Ankle Surgeons. All rights reserved.
Level of Clinical Evidence: 3
Plantar heel pain is a common complaint that occurs in approximately 10% of the population (1,2). Typically, patients present with pain on the plantar aspect of the foot at the attachment of the plantar fascia to the medial tubercle of the calcaneal process (1). Plantar fasciitis is one of the most common causes of heel pain (1,3); however, whether calcaneal spurs affect plantar fasciitis has not yet been fully elucidated (4,5). Calcaneal drilling was first described for painful heels with a calcaneal spur in 1974 (6). Barrett and Day (7) first introduced endoscopic plantar fasciotomy for chronic plantar fasciitis or heel pain. El
Financial Disclosure: This research was supported by grants from the National Natural Science Foundation of China (grant 81230040) and the China Scholarship Council has sponsored Dr B. Zhou. No additional external funding was received for the present study. Conflict of Interest: None reported. Binghua Zhou and You Zhou contributed equally to this study. Address correspondence to: Kanglai Tang, MD, PhD, Department of Orthopedic Surgery, Third Military Medical University Affiliated Southwest Hospital, Gaotanyan Street 30, Chongqing 400038 People’s Republic of China. E-mail address: [email protected] (K. Tang).
Shazly and El Beltagy (8) described an endoscopic-assisted calcaneal drilling and spur removal procedure. Treatment of plantar fasciitis has often been difficult because of the poorly understood mechanism underlying this disease. However, little doubt exists that endoscopic procedures have their advantages, including a short hospital stay, smaller wounds, and faster recovery than open surgery (9–12). More evidence has shown that plantar fasciitis should be referred to as fasciosis because of its degenerative rather than inflammatory nature (3). The significance of calcaneal spurs as a cause of plantar fasciitis has received considerable attention (4,5,13,14). A recent anatomic and histologic study showed that calcaneal spurs were manifested by endochondral ossification (13). A weightbearing compressive disturbance with secondary traction has been suggested as an underlying cause of spur growth (13). In addition, lateral heel radiographs have also confirmed a significant association between calcaneal spurs and plantar heel pain (4). Endoscopic plantar fascia release, calcaneal drilling, and calcaneal spur removal had high success and patient satisfaction rates (8), indicating that calcaneal spurs might play a role in most cases of plantar fasciitis. However,
1067-2516/$ - see front matter Ó 2015 by the American College of Foot and Ankle Surgeons. All rights reserved. http://dx.doi.org/10.1053/j.jfas.2014.11.009
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Fig. 1. (A) Lateral heel radiograph from type B calcaneal spurs. Two lines are shown: (a) an oblique line demarcating the calcaneal border and (b) a horizontal line running from the tip of the spur to the calcaneal border. The spur length was defined from the tip to the base of spur, delineated by a line demarcating the calcaneal border. (B) Radiograph taken on the second day postoperatively showing that the calcaneal spur was completely removed.
asymptomatic calcaneal spurs occur in 30% of the examined population (5). Furthermore, we have often observed that some patients with a small calcaneal spur had more serious symptoms but that other patients with large calcaneal spurs had milder complaints. In addition, a previous study showed that patients with more severe symptoms and those with symptoms for >2 years had worse results after endoscopic plantar fascia release (15). We hypothesized that different types of calcaneal spurs exist and that the grade of plantar fasciitis is dependent on its classification. Therefore, we performed a prospective study to classify the calcaneal spurs according to the findings from an investigation of the relationship between calcaneal spurs and plantar fasciitis. We initially identified 2 types of calcaneal spurs on preoperative radiographs. Next, we performed endoscopic plantar fasciotomy and calcaneal spur removal for the patients. Finally, we examined and evaluated the relationship between calcaneal spur type and each of the following: magnetic resonance imaging (MRI) results, preoperative and postoperative visual analog scale (VAS) and American Orthopedic Foot and Ankle Society (AOFAS) scores, endoscopic findings, and biopsy. Patients and Methods
single observer (B.H.Z.) measured the actual spur length on a radiograph that had not been magnified or decreased from its true size; this was confirmed using the picture archiving and communication systems software (INFINITT, INFINITT Co., Shanghai, China). In brief, 2 lines were delineated on the weightbearing lateral heel radiograph: first, a line demarcating the calcaneal border; and second, a horizontal line from the tip of the spur to the calcaneal border. The spur length was defined from the tip to the base of the spur, as defined by a line demarcating the calcaneal border (Fig. 1A). The plantar fasciitis severity was divided into 3 grades subjectively by 1 of us (B.H.Z.) according to the MRI findings. The grade for plantar fasciitis was recorded according to the ratio between the edema width and the entire width of the plantar fascia on selected oblique sagittal images: grade I, if the ratio was less than one third; grade II, if the ratio was between one and two thirds; and grade III, if the ratio was greater than two thirds (17,18).
Operative Technique The patient was positioned supine with a bolster under the contralateral hip to facilitate external rotation of the operated extremity. Routine intravenous prophylactic antibiotics (cefazolin, 0.5 g) were administered 30 minutes preoperatively by the anesthesiologist. A pneumatic tourniquet applied to the thigh was routinely used with a pressure of 270 mm Hg. Two medial portals were marked preoperatively. Portal A was located at the point of intersection between 2 lines. Line A was a vertical line along the posterior edge of the medial malleolus and line B was a horizontal line running transversely at the junction between the plantar and dorsal skin of the foot. Portal B was 1.5 to 2 cm away from portal A along line B distally (Fig. 2). The incision was made
The ethics committee of the Third Military Medical University Affiliated Southwest Hospital (Chongqing, People’s Republic of China) approved the present study, and the participants provided written informed consent. From January 2009 to March 2012, the senior author (K.L.T.) performed an endoscopic calcaneal spur removal and plantar fasciotomy procedure in 30 patients (38 feet in total). All participants has been diagnosed with calcaneal spurs (M77.31 and M77.32, international classification of disease [ICD] classification system) from the radiographic images, and the presence of plantar heel pain was determined from the patient’s history and physical examination findings. In our conservative treatment protocol, the patients were always encouraged to use a heel pad and plantar fascia stretching exercise before they underwent surgery. In the first month, we prescribed celecoxib (oral, 100 mg/d) to the patients. If the patients still complained of substantial pain, we performed a local corticosteroid injection (compound betamethasone 2 mL, which was comprised of betamethasone diproponate 5 mg and betamethasone sodium phosphate 2 mg) at 2-week intervals for a total of 3 times. All the patients had failed to respond to a trial of conservative treatment for 6 months (16). The participants in the present study were healthy, with unremarkable medical and family histories. Patients were excluded from the study if the heel pain had been caused by any pathologic entities except that of mechanical origin. Eight patients were treated bilaterally on separate occasions at a minimum interval of 3 months postoperatively. All the patients underwent MRI 1 week before surgery. Radiographic Measurements A weightbearing lateral heel radiograph was taken, and computer-aided linear measurements for spur length (mm) were performed, as previously described (4). A
Fig. 2. Line A: a vertical line along the posterior edge of the medial malleolus. Line B: a horizontal line running transversely at the junction between the plantar and dorsal skin of the foot. Portal A was located at the intersection between the 2 lines, lines A and B. Portal B was located 1.5 to 2 cm away from portal A along line B distally.
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Fig. 3. Diagram for the classification of calcaneal spurs. (A) Type A calcaneal spurs: the calcaneal spur is superior to the plantar fascia insertion. (B) Type B calcaneal spurs: the calcaneal spur stretches forward from the point of plantar fascia insertion to within the plantar fascia. The diagram is our original work.
only in the skin with a no. 11 knife blade. Next, mosquito forceps were used to dissect to the deep medial aspect of the plantar fascia. A 2.7-mm 30 endoscope (Smith & Nephew, London, United Kingdom) was introduced from the cannula in portal A. A motorized shaver was introduced from the cannula in portal B to perform the fasciotomy first. Next, one third of the medial band of the plantar fascia was removed until the calcaneal spur was completely exposed. The resected plantar fascia was sent for histologic examination. Next, the location of the calcaneal spur and the severity grade of the plantar fasciitis were determined. Then, an arthroscopic burr from the cannula in portal B was introduced to remove the calcaneal spur, and a radiofrequency transmitter electrode was used to control bleeding. The instrumentation was exchanged between portals A and B to afford better exposure and facilitate excision of the calcaneal spur and a portion of the plantar fascia. The calcaneal spur was completely excised, which was confirmed by intraoperative radiographic inspection. Finally, the cannula was removed, and the skin incision was sutured. The same operative procedure was used for all study patients.
Statistical Analysis For the statistical analysis of the data, paired-sample Student’s t tests were used to compare the preoperative and postoperative VAS and AOFAS scores. Independentsample Student’s t tests were used to assess the calcaneal spur measurements, symptom duration, body mass index, granulocytes per unit area, gender, and age among the groups. Fisher’s exact test was used to compare the MRI grade differences from preoperatively to postoperatively. Spearman’s rank correlation analyses were conducted between the classification of calcaneal spurs and the amount of change in the VAS scores and AOFAS scores, calcaneal spur length, and granulocytes per unit area. Statistical significance was defined as p .05 (5% level). The Statistical Package for Social Sciences for Windows, version 21.0 (SPSS Inc, Chicago, IL) was used for statistical analysis (performed by B.H.Z., Y.Z., and K.L.T.).
Results Postoperative Management All participants received the same postoperative protocol. Bulk dressing and limb elevation were performed for the first 24 hours. Oral celecoxib (100 mg/d) and rest were prescribed for 2 weeks to decrease the postoperative pain and edema. The patients were encouraged to start weightbearing, as tolerated, with the help of a crutch. They were also instructed to perform plantar fascia stretching exercises for 6 weeks from the second postoperative day. The patients performed the stretching exercises under the guidance of a physical therapist. In detail, a towel or strap was used to stretch the bottom of the forefoot, and it was kept in a stretched position for 10 to 20 seconds. The exercise was repeated 3 times, and the aim was to stretch the forefoot 3 times daily. We suggested that the patients wear a soft-soled slipper-like shoe with a heel pad for 6 weeks beginning when they were discharged from the inpatient department at 5 days postoperatively. The patients began to engage in normal weightbearing activities at 6 weeks postoperatively. Plain radiographs were performed on the second day postoperatively. All patients were followed up at 3, 6, 9, and 12 months after surgery and then every 6 months to obtain a VAS score for pain and AOFAS ankle-hindfoot scores for the functional evaluation. Radiographic images, MRI scans, and the VAS scores for patient satisfaction were assessed at 12 months postoperatively. Patient satisfaction was defined as a VAS score for satisfaction >8 (the data were collected by B.H.Z.).
Table 1 Patient baseline demographic characteristics (n ¼ 38 feet in 30 patients) Variable
Type A Spurs (n ¼ 28) Type B Spurs (n ¼ 10) p Value*
Preoperative VAS pain score Preoperative AOFAS score Age (y) Symptom duration (mo) BMI (kg/m2) Male gender
5.7 1.9 60.1 3.8 52.7 3.7 7.1 1.64 20.9 2.8 6 (28.57)
8.3 2.7 55.2 3.6 56.3 6.2 6.3 0.71 22.4 2.6 4 (44.44)
< .001 .24 .31 .19 .17 .55
Abbreviations: AOFAS, American Orthopedic Foot and Ankle Society; BMI, body mass index; VAS, visual analog scale. Data presented as mean standard deviation for continuous numeric data or n (%) for categorical data. * Independent-sample Student’s t test.
We identified 2 types of calcaneal spurs on the preoperative radiographs. Type A spurs were superior to the plantar fascia insertion, and type B spurs stretched forward from the plantar fascia insertion to extend distally within the plantar fascia. These spur configurations are illustrated in Fig. 3. All 30 patients completed a minimum of 12 months of follow-up after surgery, and the mean follow-up duration was 24 (range 12 to 36) months. At 12 months postoperatively, the type A calcaneal spur group included 21 (70.0%) of the 30 patients and 28 (73.68%) of the 38 feet. Of the 21 patients, 15 (71.43%) were female, with a mean average age of 52.7 (range 41 to 71) years. Of the 30 patients and 38 feet, 9 (30.0%) and 10 (26.32%), respectively, were classified as having type B calcaneal spurs. Of the 9 patients, 5 (55.56%) were female, with a mean average age of 56.3 (range 27 to 69) years. We found a statistically significant difference in the preoperative VAS score (p < .001) with respect to type A and B spurs. However, no significant difference could be detected between the type A and type B calcaneal spurs with respect to the BMI (p ¼ .17), symptom duration (p ¼ .19), age (p ¼ .31), gender (p ¼ .55), or the preoperative AOFAS score (p ¼ .24; Table 1). The mean spur length for the type A calcaneal spurs was significantly longer statistically than the mean spur length for type B calcaneal spurs (9.74 1.94 mm versus 5.43 1.78 mm, respectively; p ¼ .004). Postoperative radiographs showed that the calcaneal spurs had been completely removed (Fig. 1B). From the preoperative MRI findings, 18 (64.3%) of the 28 feet with type A calcaneal spurs were defined as grade I, 6 (21%) as grade II, and 4 (14.3%) as grade III. However, the MRI results showed that the ratio of the edema (width) of the plantar fascia in the type B calcaneal spur group was greater (Fig. 4). In the type B calcaneal spur group, 1 (10%) of the 10 feet was defined as grade II and 9 (90%) as grade III (Table 2).
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Fig. 4. (A) Magnetic resonance imaging scan showing a calcaneal spur (red arrow) superior the plantar fascia (yellow arrow) insertion in type A calcaneal spurs. (B) The type B calcaneal spur (red arrow) stretches forward from the plantar fascia insertion (white arrow) and within the plantar fascia.
The MRI scans taken 12 months postoperatively showed that the edema signal in the plantar fascia had disappeared or decreased (Fig. 5). In the type A calcaneal spur group, no plantar fasciitis was found in 7 (25%) of the 28 feet, grade I was found in 19 (67.86%), and grade II was found in 2 (7.14%) However, plantar fasciitis was defined as grade I in 2 (20%) and grade II in 8 (80%) of the 10 feet in the type B calcaneal spur group. The MRI scan analyses showed statistically significant improvement in the grade of plantar fasciitis at 1 year postoperatively in both the type A (p < .001) and type B (p < .001) spur groups (Table 2). The endoscopic findings (Fig. 6) showed that the anatomy of the calcaneal spurs was consistent with the classification made using the preoperative radiographs. Moreover, in terms of the endoscopic findings, more severe plantar fasciitis was observed in those with type B than with type A calcaneal spurs (Fig. 6), consistent with the histologic appearance of the spurs (Fig. 7). Granulocytes per 40 field were significantly enhanced in the type B calcaneal spurs (p ¼ .004). Specifically, the mean number of granulocytes per 40 field in the type A and B spurs was 416 49 and 828 84, respectively. Statistically significant improvements were found in the mean VAS scores postoperatively in both spur groups. The mean VAS score had changed from 5.7 1.9 preoperatively to 1.7 0.3 at 12 months postoperatively in the type A calcaneal spur group (p ¼ .03) and from 8.3 2.7 preoperatively to 2.4 0.4 at 12 months postoperatively in the type B calcaneal spur group (p ¼ .03; Table 3). The AOFAS scores
Table 2 Magnetic resonance imaging grade of plantar fasciitis at 12 months postoperatively in both type A (n ¼ 28 feet) and type B (n ¼ 10 feet) calcaneal spur groups Spur Group
MRI Grade
Preoperatively (n)
12 mo Postoperatively (n)
p Value*
Type A
Normal Mild Moderate Severe Normal Mild Moderate Severe
0 18 (47.37%) 6 (15.79%) 4 (10.53%) 0 0 1 (2.63%) 9 (23.68%)
7 (18.42%) 19 (50%) 2 (5.26%) 0 0 2 (5.26%) 8 (21.05%) 0
< .001
Type B
Abbreviation: MRI, magnetic resonance imaging. * Fisher’s exact test.
< .001
improved from 60.1 3.86 preoperatively to 85.4 5.43 at 12 months postoperatively in the type A calcaneal spur group (p ¼ .04) and from 55.2 3.67 preoperatively to 85.7 7.8 at 12 months postoperatively in the type B calcaneal spur group (p ¼ .02; Table 3). The amount of change in the VAS scores in the type A calcaneal spur group at 12 months postoperatively was a significant decrease compared with changes noted in the type B calcaneal spur group (p < .001). However, the amount of change in the AOFAS scores at 12 months postoperatively showed no significant difference between the 2 groups (p ¼ .21). The correlation analyses showed a correlation coefficient between the classification of calcaneal spurs and the amount of change in the VAS scores, the amount of change in the AOFAS scores, and the calcaneal spur length. The correlation coefficient for the change in VAS score, change in AOFAS score, spur length, and number of granulocytes per unit area (40 magnification field of view) was 0.63, 0.35, 0.86, and 0.95, respectively (Table 4). Two patients (22.2%) reported minimal pain tolerance in the type B calcaneal spur group at 4 months postoperatively. These 2 patients received nonsteroidal anti-inflammatory drugs (celecoxib, 100 mg/d) and heel pad treatment for 2 months. The symptoms had disappeared at 6 months postoperatively. Additionally, 2 other patients (22.2%) complained of persistent anesthesia along the plantar aspect of the hindfoot after walking for long distances. The remaining patients were fully satisfied with their clinical results at the 12-month postoperative follow-up visit. No wound infections developed, and none of the patients was experiencing plantar heel pain at the final follow-up examination.
Discussion The etiology of plantar heel pain is complex and multifactorial. Plantar fasciitis is considered to be the most common pathogenesis of a painful plantar heel (13,19). Plantar fasciitis has been associated with increased intraosseous pressure of the os calcis and the presence of calcaneal spurs (20,21). However, whether inferior calcaneal spurs have a true association with plantar fasciitis has been debated (1,22,23). Our study has shown that calcaneal spurs can be classified into 2 types and that the grade of plantar fasciitis is dependent on the classification of the calcaneal spurs.
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Fig. 5. (A and B) Magnetic resonance imaging scans showing that the affected edema width of the plantar fascia (arrows) had decreased by 12 months postoperatively.
The diagnosis of plantar fasciitis has generally been made clinically, but it can be challenging owing to the complex regional anatomy (24,25). Osborne et al (26) believed that a lateral radiograph should be the first choice for evaluating heel pain, although the key radiologic features that differentiate heel pain included changes in the soft tissues but not spurs. Ehrmann et al (27) reported that increased signal intensity within the plantar fascia with fluid-sensitive sequences was found in plantar fasciitis. Chimutengwende-Gordon et al (28) reported that a significant relationship was observed between the occurrence of night pain and calcaneal marrow edema on MRI studies. In the present study, preoperative radiographs identified 2 types of calcaneal spurs. A smaller ratio of edema width on preoperative MRI scans was found in type A calcaneal spurs compared with type B calcaneal spurs. These MRI findings were consistent with the preoperative VAS scores, indicating that patients had more severe clinical pain with type B spurs than with type A spurs. The endoscopic findings confirmed the difference between the morphology of calcaneal
spurs in the type A and B groups. Therefore, radiographs and MRI could play important roles when forming an accurate diagnosis and classification of calcaneal spurs and plantar fasciitis. Chronic plantar pain has most frequently resulted from of repetitive microtrauma or compression of neurologic structures (29,30). An excessive duration of pronation has been the most common mechanical cause of structural strain resulting in plantar fasciitis (31,32). Forman and Green (33) reported that the intrinsic musculature was the direct cause of biomechanically induced calcaneal spurs. However, asymptomatic calcaneal spurs were present in 10% to 30% of the examined population (19,20). Subcalcaneal spur formation has been suggested to be strongly associated with plantar fasciitis and plantar heel pain (2,15,34). Other alternative mechanisms, including metabolic disturbances, the formation of free radicals, hyperthermia, and genetic factors, have also been linked to degenerative changes (35,36). In the present study, we found that the grade of plantar fasciitis on the postoperative MRI studies, VAS scores (to evaluate pain), and the
Fig. 6. (A and B) Endoscopic findings in type A and B calcaneal spurs. The type A calcaneal spur (red arrow) was located superior to the point of plantar fascia insertion (black arrow). The type B calcaneal spur (red arrow) stretched forward from the point of plantar fascia insertion and was located within and was continuous with the plantar fascia.
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Fig. 7. Hematoxylin-eosin staining (original magnification 40). (A) In type A calcaneal spurs, small diameters of fibroblasts in the plantar fascia were present, with the extracellular matrix in good condition (arrow); organized tissue alignment is present. (B) In type B calcaneal spurs, abundant enlarged inflammatory cells (arrow) were present; the extracellular matrix exhibited significant degradation, with disorganized tissue alignment. We calculated the numbers of granulocytes per unit area. A semiquantification method was implemented in which 3 random images were obtained with a camera attached to a Nikon eclipse microscope (Nikon Instruments Inc, Melville, NY). In each image, the granulocytes were identified manually and analyzed using ImageJ software (National Institutes of Health, Bethesda, MD). Next, the number of granulocytes per image was calculated by averaging the mean values.
AOFAS functional evaluation showed significant improvements in both type A and type B calcaneal spur groups after excision of the calcaneal spurs. These results suggest that the type of calcaneal spurs will correlate with plantar fasciitis severity. In addition, our study has demonstrated that the numbers of granulocytes per field of view, the amount of change in the VAS scores, the amount of change in the AOFAS scores, and calcaneal spur length had a high association with the classification of the calcaneal spurs. Thus, we believe that the classification of the calcaneal spurs will be indicative of plantar fasciitis severity and of the clinical symptoms. However, the determination of a definitive etiology for plantar fasciitis and heel spurs requires additional studies. In the present study, we used 2 medial side portals that were easy to locate. Both portals were far from the tarsal tunnel, and no major complications developed in any of our patients. Endoscopic calcaneal spur excision and partial release of the plantar fascia significantly relieved the pain postoperatively in patients with type A and B calcaneal spurs. El Shazly and El Beltagy (8) performed 3 drill holes from the medial side to the lateral side and excised the spur though the modified metal cannula. In their study, 3 patients reported hyperkeratosis of the scar and 2 reported paresthesia (8). Previous studies have shown that increased intraosseous pressure and vascular congestion of the calcaneus should be considered a part of the pathogenesis of plantar fasciitis and painful heel syndrome (37–39) Endoscopic plantar fasciotomy and inferior calcaneal spur removal might decrease the intraosseous pressure and revascularize congestion of the calcaneus to a certain degree. Collectively, endoscopic plantar fasciotomy and inferior calcaneal spur removal has had a high success rate for both type A and type B calcaneal spurs.
Although both type A and B calcaneal spurs achieved good clinical outcomes postoperatively, the classification is still valuable. First, classification of the spurs will be beneficial for determining both the length of conservative treatment and the timing of surgical treatment. Also, 6 months of conservative treatment might not be needed, because it will not be as beneficial for patients with type B calcaneal spurs. It is possible that we could shorten the conservative treatment to 2 or 3 months and provide surgical options thereafter. Second, classification of spurs can help when anticipating the short-term outcomes postoperatively. Type A calcaneal spurs might realize better outcomes owing to the relatively milder degree of preoperative plantar fasciitis. Also, they might be associated with better recovery after removal of the calcaneal spurs. Finally, the classification of spurs can strengthen our understanding of the etiology of plantar fasciitis and heel pain. The present study had several limitations. First we excluded asymptomatic patients, regardless of the calcaneal spur type, because surgery was not indicated for such patients. Second, the medication (celecoxib) used might have affected the MRI results preoperatively. Third, the AOFAS hindfoot score has been under recent scrutiny with respect to its moderate level of correlation, its satisfactory degree of reliability, and its degree of responsiveness. However, the subjective component of the AOFAS clinical rating scales provides quality-of-life information that conveys acceptable validity regarding the conditions that affect the foot and ankle (40–42). Moreover, we used multiple methods to verify the classification of calcaneal spurs, including MRI, histologic examination, radiography, and self-reported outcomes. Therefore, despite these limitations, the classification of calcaneal spurs was comparatively objective. In conclusion, the results of the present study have demonstrated that calcaneal spurs can be classified into 2 distinct types. Type B
Table 3 Results of VAS score, AOFAS score, and MRI grades of plantar fasciitis at 12 months postoperatively in both type A (n ¼ 28 feet) and type B (n ¼ 10 feet) calcaneal spur groups
Table 4 Association between classification of calcaneal spurs and amount of change in VAS and AOFAS scores from preoperatively to 12 months postoperatively
Variable
Preoperatively
VAS score in type A group VAS score in type B group AOFAS score in type A group AOFAS score in type B group
5.7 8.3 60.1 55.2
1.9 2.7 3.86 3.67
12 mo Postoperatively 1.7 2.4 85.4 85.7
0.3 0.4 5.4 7.8
Variable
Type A (n ¼ 28 spurs)
Change in VAS score Change in AOFAS score Spur length (mm) Granulocytes per MF
4.0 24.86 9.74 416
p Value* .03 .03 .04 .02
Abbreviations: AOFAS, American Orthopedic Foot and Ankle Society; MRI, magnetic resonance imaging; VAS, visual analog scale. Data presented as mean standard deviation. * Paired-sample Student’s t test.
1.3 6.36 1.94 49
Type B (n ¼ 10 spurs) 6.0 29.71 5.43 828
0.5 7.45 1.78 84
Coefficient (r)* 0.63 0.35 0.86 0.95
Abbreviations: AOFAS, American Orthopedic Foot and Ankle Society; MF, magnified (40) field; VAS, visual analog scale. Data presented as mean standard deviation. * Spearman’s r correlation coefficient.
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