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Do Weight-bearing Films Affect Decision Making in Hallux Valgus Surgery?
The Journal of Foot & Ankle Surgery 51 (2012) 293–295
Contents lists available at ScienceDirect
The Journal of Foot & Ankle Surgery journal homepage: www.jfas.org
Do Weight-bearing Films Affect Decision Making in Hallux Valgus Surgery? Alon Burg, MD 1, Ori Hadash, MD 2, Yehezkel Tytiun, MD 1, Moshe Salai, MD 3, Israel Dudkiewicz, MD 3 1
Senior Surgeon, Department of Orthopaedic Surgery, Rabin Medical Center, Petach Tikva, Israel Senior Surgeon, Department of Orthopedic Surgery, Hillel Yafeh Medical Center, Hadera, Israel 3 Professor, Department of Orthopaedic Surgery, Sourasky Medical Center, Tel Aviv, Israel 2
a r t i c l e i n f o
a b s t r a c t
Level of Clinical Evidence: 3 Keywords: bunion great toe imaging metatarsal phalanx preoperative planning radiograph surgery
Hallux valgus is a complex deformity of the first ray and forefoot that can be surgically treated using different procedures and osteotomies. Preoperative planning includes anteroposterior and lateral plain films. The effect of weight-bearing on the results of the standardized measurements is still the subject of debate. We evaluated the effect of weight-bearing on the results of measurements and decision making by expert evaluators. A total of 21 foot and ankle surgeons were given weight-bearing and non–weight-bearing anteroposterior plain foot films of patients with hallux valgus. They were asked to measure 3 standard angles and then to select the most appropriate procedure from a short list. Using a paired Student’s t test, no difference in the angles measured nor in the procedures chosen was detected between the weight-bearing and non–weight-bearing films. Although it is generally accepted that decisions regarding the treatment of hallux valgus should be based on plain weight-bearing films, in the present study, we established that non–weight-bearing films can reliably be used to choose the surgical procedure. Ó 2012 by the American College of Foot and Ankle Surgeons. All rights reserved.
Hallux valgus is a complex deformity of the first ray and forefoot, present in 2% to 4% of the population (1). It is more common in women, beginning at school age. In the United States alone, 200,000 corrective operations are done annually, of which >90% are in females (2). Although >50% of the patients report the initial symptoms before 20 years of age, the condition is progressive, which explains why the mean age at surgery is 60 years (3). In male patients, the condition usually presents later in life, between the third and fifth decade (4). Hallux valgus is bilateral in about 85% of patients, and mostly affects the first metatarsophalangeal joint (2). The factors that cause and aggravate hallux valgus can be divided into intrinsic and extrinsic. The intrinsic factors are mostly inherited, and include hyperlaxity of the joints, pes planus, and familial predisposition (5). In contrast, the extrinsic factors are mostly related to improper footwear. The role of the shoes worn was clearly established by a study that compared barefoot and shoe wearing populations in China. Only 2% of the barefoot population were affected compared with 33% of the latter (6). Accordingly, treatment with flat shoes with ample space for the toes in the preliminary stages of the disease is very effective (7). Although >100 variations of corrective surgery for hallux valgus exist, the preoperative evaluation is similar. This includes anteroposterior and lateral weight-bearing plain films to enable Financial Disclosure: None reported. Conflict of Interest: None reported. Address correspondence to: Alon Burg, MD, Senior Surgeon, Department of Orthopaedic Surgery, Rabin Medical Center, Petach Tikva, Israel. E-mail address: [email protected] (A. Burg).
standardized angle measurements. In 2002, the American Orthopedic Foot and Ankle Society issued a statement, standardizing the terms and points of measurements (8). However, the effect of weightbearing on the results of the standardized measurements, affecting the decisions on the proper surgical procedure, is still the subject of much debate (9). In the present study, we evaluated the effect of weight-bearing on the results of the measurements and decision making by expert evaluators, who were unaware of the purpose of the study or the weight-bearing status of the radiographs. Materials and Methods The local ethics review board approved the present study. A total of 21 expert and ankle surgeons participated in our study. All surgeons had to have at least 5 years experience and performed >50 cases hallux valgus surgeries per year. All participants were given 20 anteroposterior foot films of 10 random clinic patients with hallux valgus. Each patient had 2 films taken, 1 weight-bearing and 1 non–weight-bearing. The weight-bearing films were taken in the standard fashion, using double stance standing with the plantar surface of the patient’s foot resting on the film. The beam was angled 10 toward the heel in the cranial-caudal direction, and the central ray was perpendicular to the metatarsal. Each film was presented separately as a right foot, without disclosure of the weight-bearing status. The surgeons were ignorant of the purpose of the study and did not know the pictures were paired. They were asked to measure 3 standard angles and then to select the most appropriate procedure from a short list. The angles were measured manually with a tractograph. No limits to the number of procedures were given. The 3 angles were as follows: 1. Hallux valgus angle (HVA) between the longitudinal axis of the first metatarsus and the proximal phalanx.
1067-2516/$ - see front matter Ó 2012 by the American College of Foot and Ankle Surgeons. All rights reserved. doi:10.1053/j.jfas.2011.11.001
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A. Burg et al. / The Journal of Foot & Ankle Surgery 51 (2012) 293–295
2. Intermetatarsal angle (IMA) between the longitudinal axes of the first and second metatarsal bones. 3. Distal metatarsal articular angle (DMAA) between the articular plane and the longitudinal axis of the first metatarsus. The list of optional interventions was as follows: soft tissue procedure, Akin osteotomy, distal osteotomy, scarf osteotomy, proximal osteotomy, first metatarsophalangeal joint arthrodesis, first tarsometatarsal joint arthrodesis, or other (to be suggested by the participant). Statistical Analysis For each of the measured parameters, in both methods, the average result of the 21 physicians was evaluated as the representative result. To compare the findings between the 2 methods we used paired Student’s t tests. For interobserver reliability, we calculated Cronbach’s alpha and intraclass correlation. All of the analyses were done using the Statistical Package for Social Sciences, version 17 (SPSS, Chicago, IL) statistical software.
Results The mean surgeon experience in foot and ankle surgery was 8 years, with an annual mean of 100 hallux valgus corrective operations. The angle measurements are listed in Table 1. The median weightbearing and supine HVA was 37.5 and 37.0 , respectively. The median weight-bearing and supine IMA was 13.5 and 12.0 , respectively. The median weight-bearing and supine DMAA was 13.5 and 15.0 , respectively. The measurements were found to fit and to be within the normal distribution using the Kolmogorov-Smirnov test. Using the paired Student’s t test, no statistically significant difference in the angles was detected between the weight-bearing and non–weightbearing films. The surgical procedures chosen by the surgeons are listed in Table 2. Each procedure is represented by the mean number of surgeons selecting that procedure (of a maximum of 21 possible). The distal osteotomy procedure was chosen 10.8 times in the weightbearing group and 11.2 times in the non–weight-bearing group. The soft tissue procedure and Akin osteotomy were usually chosen in conjunction with other procedures. As such, they were examined both as an exclusive procedure and as an adjunct to other procedures. Again, using the paired Student’s t test, no statistically significant differences were detected between the weight-bearing and non– weight-bearing choices of procedures. We also tested for interobserver reliability and found it to be high for all measurements (median 0.993). The calculated Cronbach alpha and intraclass correlations are listed in Table 3. Discussion Preoperative planning includes plain weight-bearing anteroposterior films of the feet. Several other factors should also be taken into consideration when choosing the corrective procedure, including the location of the deformity (proximal versus distal), congruency of the metatarsophalangeal joint, relative length of the first and second metatarsus, the severity of the deformity, the flexibility of the first ray and the tension in the adjacent soft tissue (1).
Table 1 Median and mean angles measured Angle
HVA IMA DMMA
Weight-bearing
Table 2 Procedures chosen Procedure
Weight-bearing
STP only Akin only STP as adjuvant Akin as adjuvant Distal osteotomy Scarf osteotomy Proximal osteotomy MTPJ arthrodesis TMTJ arthrodesis
0.5 0.2 15.2 11.7 10.8 5.8 4.9 0.6 1.4
Median
Mean
Median
Mean
37.5 (20 to 55) 13.5 (8 to 20) 13.5 (7 to 20)
35.9 9.73 13.9 4.01 13.5 4.17
37.5 (12 to 51) 12.0 (8 to 20) 15.0 (5 to 25)
33.8 11.2 12.9 4.25 14.9 5.67
p Value*
.361 .338 .268
Abbreviations: DMMA, distal metatarsal articular angle; HVA, hallux valgus angle; IMA, intermetatarsal angle. * Student’s t test.
0.60 0.48 2.00 2.87 5.81 3.64 4.20 1.26 1.90
0.3 0.2 12.9 9.9 11.2 5.0 3.0 0.6 1.4
0.42 0.42 4.20 4.93 6.10 4.90 3.94 1.07 2.01
p Value* .180 .317 .740 .131 .797 .542 .124 1.000 1.000
Abbreviations: MTPJ, metatarsophalangeal joint; STP, soft tissue procedure; TMTJ, tarsometatarsal joint. * Student’s t test.
It is generally accepted that preoperative planning should be performed using weight-bearing films. Shereff et al (10) performed measurements on both weight-bearing and non–weight-bearing plain anteroposterior films of normal and hallux valgus feet. They found differences in the HVA and IMA measurements. The changes were inconsistent. They concluded that weight-bearing films would be sufficient (10). Tanaka et al (11) measured 108 feet with hallux valgus and 100 feet without hallux valgus. Unlike our findings, they concluded that the HVA and IMA measurements increased significantly in the hallux valgus group with weight-bearing. The magnitude of the change correlated with the severity of the deformity. Fuhrmann et al (12) measured the HVA and IMA of 99 patients and found that the IMA increased with weight-bearing but the HVA was increased on non–weight-bearing films, regardless of the severity of the deformity. Coughlin and Freud (9) examined the reliability of the HVA, IMA, and DMAA measurements. Physicians were given precise instructions and examined 25 weight-bearing hallux valgus films. The inter- and intraobserver reliability were high (86% to 96%) (9). Several studies examined the effect of computerized measurements in hallux valgus. Srivastava et al (13) examined what they defined as the technical error of measurements in both manual and computed-assisted measurements. They found the error to be smaller in the computer-assisted group and the time to measure was shorter (13). In contrast to their study, Panchbhavi and Trevino (14) found no difference between the computer-assisted and manual measurements. They did find a relatively low interobserver reliability, especially in the DMAA measurement (14). In our study, we deliberately refrained from instructing the surgeons how to measure the angles, to simulate their real everyday measurements and decision making, and used photographic prints and a goniometer and a fine point pen. Our study consisted of 2 phases. First, the surgeons were asked to measure the angles on the plain films given to them. They were not aware of the study’s purpose and the pictures were assigned randomly. No differences between the weight-bearing and non– weight-bearing films were found in the angles measured. We found the distribution of the angles measured to be normal. We also tested Table 3 Calculated Cronbach’s alpha and intraclass correlations Parameter
Non–weight-bearing
Non–weight-bearing
Cronbach’s Alpha
Weight-bearing HVA 0.989 IMA 0.989 DMAA 0.936 Non–weight-bearing HVA 0.993 IMA 0.990 DMAA 0.941
Interclass Correlation
p Value
0.814 0.812 0.412
< .001 < .001 .002
0.865 0.819 0.431
< .001 < .001 .001
Abbreviations: DMMA, distal metatarsal articular angle; HVA, hallux valgus angle; IMA, intermetatarsal angle.
A. Burg et al. / The Journal of Foot & Ankle Surgery 51 (2012) 293–295
the interobserver reliability and found it to be extremely high, about 0.993. In the second phase, we asked the surgeons to choose their preferred treatment plan for the case presented to them from a list of procedures. We did not limit the number of answers (i.e., the surgeons were able to choose a combination of osteotomies such as scarf osteotomy plus Akin osteotomy. No differences were observed in the preferred surgical options. This can be explained by the following arguments. Because no differences in the angles measured were observed, no differences in the procedures chosen should be expected. Also, surgeons will generally choose their procedure from their personal preference and habit, regardless of the angles measured. Our study had several strengths. First, although several earlier studies tried to determine the “correct” method for measuring hallux valgus angles and to check for inter- and intraobserver variability, our study’s primary outcome was the final applicable result of the measurements (i.e., the surgical procedure chosen). Second, the surgeons were unaware of the purpose of our study or the possibility of weight-bearing or non–weight-bearing films and, therefore, were not biased. Third, we did not instruct the surgeons on how to measure the angles. Although not instructing the surgeons on the exact method to measure the angles might be viewed as a study weakness by some, we believe this was a strength, mainly because this would simulated their personal “real life” clinical practice. The relative weakness of the present study was the lack of clinical evaluation of the patient’s foot that also comes into consideration when choosing a procedure. Although intuitively one could argue that weight-bearing films reflect the true deformity, in our study, we found no differences in either the angle measurement or in the procedure selection. In conclusion, the findings of this investigation suggest that foot and ankle surgeons can reliably use non–weight-bearing films to
295
decide on their preferred corrective procedure. Other factors such as metatarsophalangeal joint congruence, arthritic changes, and first ray hypermobility should also be considered. References 1. Myerson MS. Hallux valgus. In: Foot and Ankle Disorders, pp 213–289, WB Saunders, Philadelphia, 2000. 2. Coughlin MJ, Jones CP. Hallux valgus: demographics, radiographic assessment and clinical outcome: a prospective study. Presented at the 21st Annual Summer Meeting of the AOFAS, July 17, 2005. 3. Coughlin MJ. Juvenile hallux valgus: etiology and treatment. Foot Ankle Int 16:682–697, 1995. 4. Coughlin MJ. Hallux valgus in men: effect of the distal metatarsal articular angle on hallux valgus correction. Foot Ankle Int 18:463–470, 1997. 5. Mann RA, Coughlin MJ. Hallux valgusdetiology, anatomy, treatment and surgical considerations. Clin Orthop 157:31–41, 1981. 6. Sim-Fook L, Hodgson AR. A comparison of foot forms among the non-shoe and shoe-wearing Chinese population. J Bone Joint Surg Am 40:1058–1062, 1958. 7. Groiso JA. Juvenile hallux valgus: a conservative approach to treatment. J Bone Joint Surg Am 74:1367–1374, 1992. 8. Coughlin MJ, Saltzman CL, Nunley JA. Angular measurements in the evaluation of hallux valgus deformities: a report of the Ad Hoc Committee of the American Orthopedic Foot and Ankle Society on angular measurements. Foot Ankle Int 23:68–74, 2002. 9. Coughlin MJ, Freud E. The reliability of angular measurements in hallux valgus deformities. Foot Ankle Int 22:369–379, 2001. 10. Shereff MJ, DiGiovanni L, Bejjani FJ, Hersh A, Kummer FJ. A comparison of nonweight-bearing and weight-bearing radiographs of the foot. Foot Ankle 10:306–311, 1990. 11. Tanaka Y, Takakura Y, Takaoka T, Akiyama K, Fujii T, Tamai S. Radiographic analysis of hallux valgus in women on weightbearing and nonweightbearing. Clin Orthop Relat Res 336:186–194, 1997. 12. Fuhrmann RA, Layher F, Wetzel WD. Radiographic changes in forefoot geometry with weightbearing. Foot Ankle Int 24:326–331, 2003. 13. Srivastava S, Chockalingam N, El Fakhri T. Radiographic angles in hallux valgus: comparison between manual and computer-assisted measurements. J Foot Ankle Surg 49:523–528, 2010. 14. Panchbhavi VK, Trevino S. Comparison between manual and computer-assisted measurements of hallux valgus parameters. Foot Ankle Int 25:708–711, 2004.
Contents lists available at ScienceDirect
The Journal of Foot & Ankle Surgery journal homepage: www.jfas.org
Do Weight-bearing Films Affect Decision Making in Hallux Valgus Surgery? Alon Burg, MD 1, Ori Hadash, MD 2, Yehezkel Tytiun, MD 1, Moshe Salai, MD 3, Israel Dudkiewicz, MD 3 1
Senior Surgeon, Department of Orthopaedic Surgery, Rabin Medical Center, Petach Tikva, Israel Senior Surgeon, Department of Orthopedic Surgery, Hillel Yafeh Medical Center, Hadera, Israel 3 Professor, Department of Orthopaedic Surgery, Sourasky Medical Center, Tel Aviv, Israel 2
a r t i c l e i n f o
a b s t r a c t
Level of Clinical Evidence: 3 Keywords: bunion great toe imaging metatarsal phalanx preoperative planning radiograph surgery
Hallux valgus is a complex deformity of the first ray and forefoot that can be surgically treated using different procedures and osteotomies. Preoperative planning includes anteroposterior and lateral plain films. The effect of weight-bearing on the results of the standardized measurements is still the subject of debate. We evaluated the effect of weight-bearing on the results of measurements and decision making by expert evaluators. A total of 21 foot and ankle surgeons were given weight-bearing and non–weight-bearing anteroposterior plain foot films of patients with hallux valgus. They were asked to measure 3 standard angles and then to select the most appropriate procedure from a short list. Using a paired Student’s t test, no difference in the angles measured nor in the procedures chosen was detected between the weight-bearing and non–weight-bearing films. Although it is generally accepted that decisions regarding the treatment of hallux valgus should be based on plain weight-bearing films, in the present study, we established that non–weight-bearing films can reliably be used to choose the surgical procedure. Ó 2012 by the American College of Foot and Ankle Surgeons. All rights reserved.
Hallux valgus is a complex deformity of the first ray and forefoot, present in 2% to 4% of the population (1). It is more common in women, beginning at school age. In the United States alone, 200,000 corrective operations are done annually, of which >90% are in females (2). Although >50% of the patients report the initial symptoms before 20 years of age, the condition is progressive, which explains why the mean age at surgery is 60 years (3). In male patients, the condition usually presents later in life, between the third and fifth decade (4). Hallux valgus is bilateral in about 85% of patients, and mostly affects the first metatarsophalangeal joint (2). The factors that cause and aggravate hallux valgus can be divided into intrinsic and extrinsic. The intrinsic factors are mostly inherited, and include hyperlaxity of the joints, pes planus, and familial predisposition (5). In contrast, the extrinsic factors are mostly related to improper footwear. The role of the shoes worn was clearly established by a study that compared barefoot and shoe wearing populations in China. Only 2% of the barefoot population were affected compared with 33% of the latter (6). Accordingly, treatment with flat shoes with ample space for the toes in the preliminary stages of the disease is very effective (7). Although >100 variations of corrective surgery for hallux valgus exist, the preoperative evaluation is similar. This includes anteroposterior and lateral weight-bearing plain films to enable Financial Disclosure: None reported. Conflict of Interest: None reported. Address correspondence to: Alon Burg, MD, Senior Surgeon, Department of Orthopaedic Surgery, Rabin Medical Center, Petach Tikva, Israel. E-mail address: [email protected] (A. Burg).
standardized angle measurements. In 2002, the American Orthopedic Foot and Ankle Society issued a statement, standardizing the terms and points of measurements (8). However, the effect of weightbearing on the results of the standardized measurements, affecting the decisions on the proper surgical procedure, is still the subject of much debate (9). In the present study, we evaluated the effect of weight-bearing on the results of the measurements and decision making by expert evaluators, who were unaware of the purpose of the study or the weight-bearing status of the radiographs. Materials and Methods The local ethics review board approved the present study. A total of 21 expert and ankle surgeons participated in our study. All surgeons had to have at least 5 years experience and performed >50 cases hallux valgus surgeries per year. All participants were given 20 anteroposterior foot films of 10 random clinic patients with hallux valgus. Each patient had 2 films taken, 1 weight-bearing and 1 non–weight-bearing. The weight-bearing films were taken in the standard fashion, using double stance standing with the plantar surface of the patient’s foot resting on the film. The beam was angled 10 toward the heel in the cranial-caudal direction, and the central ray was perpendicular to the metatarsal. Each film was presented separately as a right foot, without disclosure of the weight-bearing status. The surgeons were ignorant of the purpose of the study and did not know the pictures were paired. They were asked to measure 3 standard angles and then to select the most appropriate procedure from a short list. The angles were measured manually with a tractograph. No limits to the number of procedures were given. The 3 angles were as follows: 1. Hallux valgus angle (HVA) between the longitudinal axis of the first metatarsus and the proximal phalanx.
1067-2516/$ - see front matter Ó 2012 by the American College of Foot and Ankle Surgeons. All rights reserved. doi:10.1053/j.jfas.2011.11.001
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A. Burg et al. / The Journal of Foot & Ankle Surgery 51 (2012) 293–295
2. Intermetatarsal angle (IMA) between the longitudinal axes of the first and second metatarsal bones. 3. Distal metatarsal articular angle (DMAA) between the articular plane and the longitudinal axis of the first metatarsus. The list of optional interventions was as follows: soft tissue procedure, Akin osteotomy, distal osteotomy, scarf osteotomy, proximal osteotomy, first metatarsophalangeal joint arthrodesis, first tarsometatarsal joint arthrodesis, or other (to be suggested by the participant). Statistical Analysis For each of the measured parameters, in both methods, the average result of the 21 physicians was evaluated as the representative result. To compare the findings between the 2 methods we used paired Student’s t tests. For interobserver reliability, we calculated Cronbach’s alpha and intraclass correlation. All of the analyses were done using the Statistical Package for Social Sciences, version 17 (SPSS, Chicago, IL) statistical software.
Results The mean surgeon experience in foot and ankle surgery was 8 years, with an annual mean of 100 hallux valgus corrective operations. The angle measurements are listed in Table 1. The median weightbearing and supine HVA was 37.5 and 37.0 , respectively. The median weight-bearing and supine IMA was 13.5 and 12.0 , respectively. The median weight-bearing and supine DMAA was 13.5 and 15.0 , respectively. The measurements were found to fit and to be within the normal distribution using the Kolmogorov-Smirnov test. Using the paired Student’s t test, no statistically significant difference in the angles was detected between the weight-bearing and non–weightbearing films. The surgical procedures chosen by the surgeons are listed in Table 2. Each procedure is represented by the mean number of surgeons selecting that procedure (of a maximum of 21 possible). The distal osteotomy procedure was chosen 10.8 times in the weightbearing group and 11.2 times in the non–weight-bearing group. The soft tissue procedure and Akin osteotomy were usually chosen in conjunction with other procedures. As such, they were examined both as an exclusive procedure and as an adjunct to other procedures. Again, using the paired Student’s t test, no statistically significant differences were detected between the weight-bearing and non– weight-bearing choices of procedures. We also tested for interobserver reliability and found it to be high for all measurements (median 0.993). The calculated Cronbach alpha and intraclass correlations are listed in Table 3. Discussion Preoperative planning includes plain weight-bearing anteroposterior films of the feet. Several other factors should also be taken into consideration when choosing the corrective procedure, including the location of the deformity (proximal versus distal), congruency of the metatarsophalangeal joint, relative length of the first and second metatarsus, the severity of the deformity, the flexibility of the first ray and the tension in the adjacent soft tissue (1).
Table 1 Median and mean angles measured Angle
HVA IMA DMMA
Weight-bearing
Table 2 Procedures chosen Procedure
Weight-bearing
STP only Akin only STP as adjuvant Akin as adjuvant Distal osteotomy Scarf osteotomy Proximal osteotomy MTPJ arthrodesis TMTJ arthrodesis
0.5 0.2 15.2 11.7 10.8 5.8 4.9 0.6 1.4
Median
Mean
Median
Mean
37.5 (20 to 55) 13.5 (8 to 20) 13.5 (7 to 20)
35.9 9.73 13.9 4.01 13.5 4.17
37.5 (12 to 51) 12.0 (8 to 20) 15.0 (5 to 25)
33.8 11.2 12.9 4.25 14.9 5.67
p Value*
.361 .338 .268
Abbreviations: DMMA, distal metatarsal articular angle; HVA, hallux valgus angle; IMA, intermetatarsal angle. * Student’s t test.
0.60 0.48 2.00 2.87 5.81 3.64 4.20 1.26 1.90
0.3 0.2 12.9 9.9 11.2 5.0 3.0 0.6 1.4
0.42 0.42 4.20 4.93 6.10 4.90 3.94 1.07 2.01
p Value* .180 .317 .740 .131 .797 .542 .124 1.000 1.000
Abbreviations: MTPJ, metatarsophalangeal joint; STP, soft tissue procedure; TMTJ, tarsometatarsal joint. * Student’s t test.
It is generally accepted that preoperative planning should be performed using weight-bearing films. Shereff et al (10) performed measurements on both weight-bearing and non–weight-bearing plain anteroposterior films of normal and hallux valgus feet. They found differences in the HVA and IMA measurements. The changes were inconsistent. They concluded that weight-bearing films would be sufficient (10). Tanaka et al (11) measured 108 feet with hallux valgus and 100 feet without hallux valgus. Unlike our findings, they concluded that the HVA and IMA measurements increased significantly in the hallux valgus group with weight-bearing. The magnitude of the change correlated with the severity of the deformity. Fuhrmann et al (12) measured the HVA and IMA of 99 patients and found that the IMA increased with weight-bearing but the HVA was increased on non–weight-bearing films, regardless of the severity of the deformity. Coughlin and Freud (9) examined the reliability of the HVA, IMA, and DMAA measurements. Physicians were given precise instructions and examined 25 weight-bearing hallux valgus films. The inter- and intraobserver reliability were high (86% to 96%) (9). Several studies examined the effect of computerized measurements in hallux valgus. Srivastava et al (13) examined what they defined as the technical error of measurements in both manual and computed-assisted measurements. They found the error to be smaller in the computer-assisted group and the time to measure was shorter (13). In contrast to their study, Panchbhavi and Trevino (14) found no difference between the computer-assisted and manual measurements. They did find a relatively low interobserver reliability, especially in the DMAA measurement (14). In our study, we deliberately refrained from instructing the surgeons how to measure the angles, to simulate their real everyday measurements and decision making, and used photographic prints and a goniometer and a fine point pen. Our study consisted of 2 phases. First, the surgeons were asked to measure the angles on the plain films given to them. They were not aware of the study’s purpose and the pictures were assigned randomly. No differences between the weight-bearing and non– weight-bearing films were found in the angles measured. We found the distribution of the angles measured to be normal. We also tested Table 3 Calculated Cronbach’s alpha and intraclass correlations Parameter
Non–weight-bearing
Non–weight-bearing
Cronbach’s Alpha
Weight-bearing HVA 0.989 IMA 0.989 DMAA 0.936 Non–weight-bearing HVA 0.993 IMA 0.990 DMAA 0.941
Interclass Correlation
p Value
0.814 0.812 0.412
< .001 < .001 .002
0.865 0.819 0.431
< .001 < .001 .001
Abbreviations: DMMA, distal metatarsal articular angle; HVA, hallux valgus angle; IMA, intermetatarsal angle.
A. Burg et al. / The Journal of Foot & Ankle Surgery 51 (2012) 293–295
the interobserver reliability and found it to be extremely high, about 0.993. In the second phase, we asked the surgeons to choose their preferred treatment plan for the case presented to them from a list of procedures. We did not limit the number of answers (i.e., the surgeons were able to choose a combination of osteotomies such as scarf osteotomy plus Akin osteotomy. No differences were observed in the preferred surgical options. This can be explained by the following arguments. Because no differences in the angles measured were observed, no differences in the procedures chosen should be expected. Also, surgeons will generally choose their procedure from their personal preference and habit, regardless of the angles measured. Our study had several strengths. First, although several earlier studies tried to determine the “correct” method for measuring hallux valgus angles and to check for inter- and intraobserver variability, our study’s primary outcome was the final applicable result of the measurements (i.e., the surgical procedure chosen). Second, the surgeons were unaware of the purpose of our study or the possibility of weight-bearing or non–weight-bearing films and, therefore, were not biased. Third, we did not instruct the surgeons on how to measure the angles. Although not instructing the surgeons on the exact method to measure the angles might be viewed as a study weakness by some, we believe this was a strength, mainly because this would simulated their personal “real life” clinical practice. The relative weakness of the present study was the lack of clinical evaluation of the patient’s foot that also comes into consideration when choosing a procedure. Although intuitively one could argue that weight-bearing films reflect the true deformity, in our study, we found no differences in either the angle measurement or in the procedure selection. In conclusion, the findings of this investigation suggest that foot and ankle surgeons can reliably use non–weight-bearing films to
295
decide on their preferred corrective procedure. Other factors such as metatarsophalangeal joint congruence, arthritic changes, and first ray hypermobility should also be considered. References 1. Myerson MS. Hallux valgus. In: Foot and Ankle Disorders, pp 213–289, WB Saunders, Philadelphia, 2000. 2. Coughlin MJ, Jones CP. Hallux valgus: demographics, radiographic assessment and clinical outcome: a prospective study. Presented at the 21st Annual Summer Meeting of the AOFAS, July 17, 2005. 3. Coughlin MJ. Juvenile hallux valgus: etiology and treatment. Foot Ankle Int 16:682–697, 1995. 4. Coughlin MJ. Hallux valgus in men: effect of the distal metatarsal articular angle on hallux valgus correction. Foot Ankle Int 18:463–470, 1997. 5. Mann RA, Coughlin MJ. Hallux valgusdetiology, anatomy, treatment and surgical considerations. Clin Orthop 157:31–41, 1981. 6. Sim-Fook L, Hodgson AR. A comparison of foot forms among the non-shoe and shoe-wearing Chinese population. J Bone Joint Surg Am 40:1058–1062, 1958. 7. Groiso JA. Juvenile hallux valgus: a conservative approach to treatment. J Bone Joint Surg Am 74:1367–1374, 1992. 8. Coughlin MJ, Saltzman CL, Nunley JA. Angular measurements in the evaluation of hallux valgus deformities: a report of the Ad Hoc Committee of the American Orthopedic Foot and Ankle Society on angular measurements. Foot Ankle Int 23:68–74, 2002. 9. Coughlin MJ, Freud E. The reliability of angular measurements in hallux valgus deformities. Foot Ankle Int 22:369–379, 2001. 10. Shereff MJ, DiGiovanni L, Bejjani FJ, Hersh A, Kummer FJ. A comparison of nonweight-bearing and weight-bearing radiographs of the foot. Foot Ankle 10:306–311, 1990. 11. Tanaka Y, Takakura Y, Takaoka T, Akiyama K, Fujii T, Tamai S. Radiographic analysis of hallux valgus in women on weightbearing and nonweightbearing. Clin Orthop Relat Res 336:186–194, 1997. 12. Fuhrmann RA, Layher F, Wetzel WD. Radiographic changes in forefoot geometry with weightbearing. Foot Ankle Int 24:326–331, 2003. 13. Srivastava S, Chockalingam N, El Fakhri T. Radiographic angles in hallux valgus: comparison between manual and computer-assisted measurements. J Foot Ankle Surg 49:523–528, 2010. 14. Panchbhavi VK, Trevino S. Comparison between manual and computer-assisted measurements of hallux valgus parameters. Foot Ankle Int 25:708–711, 2004.