ORIGINAL ARTICLE
Radial Polydactyly and the Incidence of Reoperation Using A New Classification System Brian J. Evanson, MD, Pooya Hosseinzadeh, MD, Scott A. Riley, MD, and Ronlad C. Burgess, MD
Background: Polydactyly is one of the more common congenital deformities with an incidence of 0.8 to 1.4 per 1000. Traditionally the Wassel Classification system has been used, which is based on the level of duplication seen on plain radiographs. Although it is helpful in describing the anatomic characteristics, it is somewhat limited with regards to surgical planning and postoperative outcomes. Chung and colleagues, recently proposed a new classification system that categorizes radial polydactyly based on morphologic features that provides helpful information to be used in surgical decision making. We reviewed all radial polydactyly cases that had undergone operative intervention at our center over a 10-year period to investigate if this new classification system correlates with the rate of reoperation. Methods: A total of 60 thumbs in 54 patients that were treated surgically from 2000 to 2010 at our institution were included in this study. Only patients with a minimum follow-up of 2 years were included. The authors categorized all duplications based on the classification system proposed by Chung and colleagues: type I (Joint Type), type II (Single Epiphyseal Type), type III (Osteochondroma-like Type), and type IV (Hypoplastic Type). Statistical analysis was then used to look at this classification system as it relates to sex, family history, syndrome association, and the need for reoperation. Results: Of the 60 radial polydactyly cases, 37 (62%) were type I; 6 (10%) were type II; 6 (10%) were type III; and 11 (18%) were type IV. Six thumbs underwent reoperation for residual deformity—3 type I, 3 type II, and none of the types III or IV. No statistical significance was found when comparing classification group to sex, family history, syndrome association, laterality, or bilateral involvement. Statistical significance (P < 0.05) was found between groups and the need for reoperation. Conclusions: The new classification system proposed by Chung and colleagues is easy to use and can guide practitioners in their discussions with patients regarding surgical outcomes and possible need for revision surgery. Level of Evidence: Level II—retrospective. Key Words: radial polydactyly, thumb duplication, congenital difference (J Pediatr Orthop 2016;36:158–160) From the Shriners Hospital for Children, Lexington, KY. The authors declare no conflicts of interest. Reprints: Pooya Hosseinzadeh, MD, Shriners Hospital for Children, 1900 Richmond Road, Lexington, KY 40502. E-mail: pooya [email protected]. Copyright r 2015 Wolters Kluwer Health, Inc. All rights reserved.
158 | www.pedorthopaedics.com
P
olydactyly is one of the more common congenital differences affecting the pediatric hand. Radial polydactyly, or duplication of the thumb, can occur at multiple levels and has varying clinical presentations. Its prevalence varies among ethnic groups but is most common in Asians and white Americans with a range of 0.8 to 1.4 per 1000.1–5 Classically, the Wassel system has been used for describing these duplications. Each group is classified based on the level of duplication seen on plain radiographs.6 The classification system is useful in categorizing the duplication and communicating the information between surgeons. It is somewhat limited, however, in regard to its effectiveness in aiding with preoperative planning and correlation with postoperative outcomes.3,5,7 Chung et al8 have recently proposed a new classification system for radial polydactyly that categorizes the duplication based on morphologic features; these features can then be used to aid in preoperative planning and surgical decision making. The Chung et al8 system is divided into 4 distinct groups: type I (Joint Type), type II (Single Epiphyseal Type), type III (Osteochondroma-like Type), and type IV (Hypoplastic Type), and each group is closely related to the surgical strategy for correction. Given its practicality and usefulness in the preoperative planning, the authors investigated the correlation of this classification system with the reoperation rates. Also, we were interested to see if reoperation rates were affected due to sex, laterality, bilateral involvement, family history, or associated syndromes.
METHODS A total of 60 thumbs in 54 patients were treated surgically for radial polydactyly from 2000 to 2010 at our institution. 2010 was chosen as the last year of our collection as all patients needed to have at least 2 years of potential follow-up. The authors categorized all surgical cases based on the classification system proposed by Chung and colleagues (Fig. 1), using the patient’s medical records and radiographs. The charts were reviewed for sex, laterality, bilateral involvement, a family history of duplication, and associated syndromes that were then documented. All charts were reviewed in their entirety to assess for any complications that arose and the need for reoperation. Statistical testing using w2 analysis was then used to look for any statistical significance between the groups. J Pediatr Orthop
Volume 36, Number 2, March 2016
Copyright r 2016 Wolters Kluwer Health, Inc. All rights reserved.
J Pediatr Orthop
Volume 36, Number 2, March 2016
Type 1 Joint type
Radial Polydactyly and the Incidence of Reoperation
Type 2: Single Epiphyseal type
Type 3: Osteochondroma type
Type 4: Hypoplastic type
FIGURE 1. Different types of thumb polydactyly. Type I: Each digit has its own joint at its origin. Type II: The origin of the duplicated digit arises from a common epiphysis. Type III: The origin of the duplicated digit resembles an osteochondroma. Type IV: The duplicated digit is attached by soft tissue alone. Adapted from Chung et al.8 Adaptations are themselves works protected by copyright. So in order to publish this adaptation, authorization must be obtained both from the owner of the copyright in the original work and from the owner of copyright in the translation or adaptation.
RESULTS A total of 60 duplicated thumbs in 54 patients (34 males and 20 females) underwent surgical intervention between 2000 and 2010. The mean age at the time of surgery was 1.3 years (range, 6.5 mo to 8 y 11 mo). Eight patients had an associated syndrome though no 1 syndrome was most prevalent. Of the 54 patients treated surgically, 8 patients had a family history of duplication for an overall rate of 14.8%. The results are listed in Tables 1 and 2. Of the 60 surgical radial polydactyly cases, a total of 8 cases underwent reoperation but only 6 were considered in our statistical analysis. The 2 cases that were excluded had returned to the operating room for a pin removal (that in every other case was performed in the clinic) and for an elective scar revision 5 years postoperatively. Of the 6 cases considered as true reoperations for our study, 3 were type I and 3 were type II for overall reoperation rates for types I and II of 8% and 50%, respectively. Reoperations were performed for radial collateral ligament instability, recurrent angular deformity at the MCP/
IP joint or nail-bed/nail-plate issues. No types III or IV required reoperation during our follow-up period. The reoperation rate overall was 10%. w2 statistical analysis showed no statistical significance (P > 0.05) between reoperation and sex (P = 0.536), family history (P = 0.830), syndrome association (P = 0.311), laterality (P = 0.928), and bilateral involvement (P = 0.389). Statistical significance was seen with the new classification system and reoperation rate (P = 0.005) where the reoperation rate was significantly higher in types I and II than III or IV.
DISCUSSION The Wassel classification system for radial polydactyly has remained the most used method for describing thumb duplications. Although it is useful for describing the level of duplication, the subgroups do not correlate with specific surgical approaches or postoperative outcomes. In fact, many of the Wassel groups have similar morphology and would require similar operative interventions (ie, Wassel 2-4-6 or Wassel 3-5).
TABLE 1. Chung and Colleagues Distribution Chung and Colleagues Classification Group I II III IV
Copyright
r
No. Cases
Total Cases (%)
No. Reoperations
Reoperation Rate (%)
37 6 6 11
62 10 10 18
3 3 0 0
8 50 0 0
2015 Wolters Kluwer Health, Inc. All rights reserved.
www.pedorthopaedics.com |
Copyright r 2016 Wolters Kluwer Health, Inc. All rights reserved.
159
J Pediatr Orthop
Evanson et al
Volume 36, Number 2, March 2016
TABLE 2. Wassel Distribution Wassel Group I II III IV V VI VII
No. Cases
Total Cases (%)
No. Reoperations
Reoperation Rate (%)
0 16 2 28 2 4 8
0 27 3 47 3 7 13
0 3 0 3 0 0 0
0 19 0 11 0 0 0
Chung et al8 proposed a new classification system with 4 unique subgroups. Our data indicate there was a statistically significant association between reoperation and the Chung and colleagues classification system typology (P = 0.005) but no other statistical significance between other variables. This information has important clinical implications. For example, for the child with a Chung Types I or II duplication, a more informative discussion can be held with the family about the potential need for revision surgery and the possibility of less than optimal surgical outcomes. In addition, it can guide the physician in terms of postoperative follow-up care. Types III and IV thumb duplications did not undergo any reoperations and therefore these thumbs could potentially require shorter postoperative follow-up periods. However, those with types I or II thumbs were found to have an increased potential for reoperation. Therefore, it can be inferred that these patients may need to be followed for a longer time period to monitor clinical parameters such as angulation deformity or joint instability. There are only a few studies looking at large cohorts of surgically treated radial polydactyly, but our distribution of subtypes and reoperation rates seem to be comparable to these. The present study’s distributions are listed in Tables 1 and 2 and the overall reoperation rate was 10%. Chung et al8 had distributions of type I being the most common with 50% (ours 62%), type II, 18% (ours 10%), type III, 20% (ours 10%), and type IV, 7% (ours 18%). No reoperation rate was given for their study. Tada et al5 operated on 94 primary thumbs with distributions using a modified Wassel system showing types II and IV to be the most common at 16% and 44%, respectively. Our distributions were similar with type II at 27% and type IV at 47%. No reoperation rate was given for their study but outcomes showed poor results in 4.3% and fair results in 20.2%.5 Ogino and colleagues operated on 113 thumbs with a modified Wassel classification system showing types II and IV to be the most common at 25% and 42%, respectively—very similar to ours. Their outcomes showed a poor result in 3.5% of cases and a fair result in 11%—their reoperation rate was 11.5%.3 Our study shows similar distributions and reoperation rates indicating this new classification system’s validity and usefulness.
160 | www.pedorthopaedics.com
The present study did have some limitations. The indications for reoperation were not based on any hard radiographic parameters but rather on the thumb’s clinical presentation. Although it would be helpful to define what the angular deformity was numerically, this would be extremely difficult as radiographs were not commonly ordered on all patients unless clinically warranted. Other patients requiring revision for ligamentous instability or nail deformity would not fall into this group either. In addition, while most patients remain within our hospital system for their care (and it was assumed that those patients not presenting complaining of issues or deformity had good results), we cannot rule out the possibility that some patients may have presented elsewhere requiring revision surgery. In conclusion, it is known that the Chung et al8 classification system provides an anatomic method to describe thumb duplication that can assist in planning surgical treatment. The data presented here support that this classification system also gives meaningful information in regard to the potential for revision surgery. Thus, using the Chung and colleagues system as the new standard for classifying radial polydactyly will not only aid in preoperative planning, but it can guide the physician in managing long-term patient care, and educating families about expected treatment outcomes. REFERENCES 1. Dobyns JH, Lipscomb PR, Cooney WP. Management of thumb duplication. Clin Orthop Relat Res. 1985;195:26–44. 2. Ezaki M. Radial polydactyly. Hand Clin. 1990;6:577–588. 3. Ogino T, Ishii S, Takahata S, et al. Long-term results of surgical treatment of thumb polydactyly. J Hand Surg Am. 1996;21:478–486. 4. Seidman GD, Wenner SM. Surgical treatment of the duplicated thumb. J Pediatr Orthop. 1993;13:660–662. 5. Tada K, Yonenobu K, Tsuyuguchi Y, et al. Duplication of the thumb. A retrospective review of two hundred and thirty-seven cases. J Bone Joint Surg. 1983;65A:584–598. 6. Wassel HD. The results of surgery for polydactyly of the thumb. A review. Clin Orthop Relat Res. 1969;64:175–193. 7. Manske PR, Oberg KC. Classification and developmental biology of congenital anomalies of the hand and upper extremity. J Bone Joint Surg. 2009;91(suppl 4):3–18. 8. Chung MS, Baek GH, Gong HS, et al. Radial polydactyly: proposal for a new classification system based on the 159 duplicated thumbs. J Pediatr Orthop. 2013;33:190–196.
Copyright
r
2015 Wolters Kluwer Health, Inc. All rights reserved.
Copyright r 2016 Wolters Kluwer Health, Inc. All rights reserved.
Radial Polydactyly and the Incidence of Reoperation Using A New Classification System Brian J. Evanson, MD, Pooya Hosseinzadeh, MD, Scott A. Riley, MD, and Ronlad C. Burgess, MD
Background: Polydactyly is one of the more common congenital deformities with an incidence of 0.8 to 1.4 per 1000. Traditionally the Wassel Classification system has been used, which is based on the level of duplication seen on plain radiographs. Although it is helpful in describing the anatomic characteristics, it is somewhat limited with regards to surgical planning and postoperative outcomes. Chung and colleagues, recently proposed a new classification system that categorizes radial polydactyly based on morphologic features that provides helpful information to be used in surgical decision making. We reviewed all radial polydactyly cases that had undergone operative intervention at our center over a 10-year period to investigate if this new classification system correlates with the rate of reoperation. Methods: A total of 60 thumbs in 54 patients that were treated surgically from 2000 to 2010 at our institution were included in this study. Only patients with a minimum follow-up of 2 years were included. The authors categorized all duplications based on the classification system proposed by Chung and colleagues: type I (Joint Type), type II (Single Epiphyseal Type), type III (Osteochondroma-like Type), and type IV (Hypoplastic Type). Statistical analysis was then used to look at this classification system as it relates to sex, family history, syndrome association, and the need for reoperation. Results: Of the 60 radial polydactyly cases, 37 (62%) were type I; 6 (10%) were type II; 6 (10%) were type III; and 11 (18%) were type IV. Six thumbs underwent reoperation for residual deformity—3 type I, 3 type II, and none of the types III or IV. No statistical significance was found when comparing classification group to sex, family history, syndrome association, laterality, or bilateral involvement. Statistical significance (P < 0.05) was found between groups and the need for reoperation. Conclusions: The new classification system proposed by Chung and colleagues is easy to use and can guide practitioners in their discussions with patients regarding surgical outcomes and possible need for revision surgery. Level of Evidence: Level II—retrospective. Key Words: radial polydactyly, thumb duplication, congenital difference (J Pediatr Orthop 2016;36:158–160) From the Shriners Hospital for Children, Lexington, KY. The authors declare no conflicts of interest. Reprints: Pooya Hosseinzadeh, MD, Shriners Hospital for Children, 1900 Richmond Road, Lexington, KY 40502. E-mail: pooya [email protected]. Copyright r 2015 Wolters Kluwer Health, Inc. All rights reserved.
158 | www.pedorthopaedics.com
P
olydactyly is one of the more common congenital differences affecting the pediatric hand. Radial polydactyly, or duplication of the thumb, can occur at multiple levels and has varying clinical presentations. Its prevalence varies among ethnic groups but is most common in Asians and white Americans with a range of 0.8 to 1.4 per 1000.1–5 Classically, the Wassel system has been used for describing these duplications. Each group is classified based on the level of duplication seen on plain radiographs.6 The classification system is useful in categorizing the duplication and communicating the information between surgeons. It is somewhat limited, however, in regard to its effectiveness in aiding with preoperative planning and correlation with postoperative outcomes.3,5,7 Chung et al8 have recently proposed a new classification system for radial polydactyly that categorizes the duplication based on morphologic features; these features can then be used to aid in preoperative planning and surgical decision making. The Chung et al8 system is divided into 4 distinct groups: type I (Joint Type), type II (Single Epiphyseal Type), type III (Osteochondroma-like Type), and type IV (Hypoplastic Type), and each group is closely related to the surgical strategy for correction. Given its practicality and usefulness in the preoperative planning, the authors investigated the correlation of this classification system with the reoperation rates. Also, we were interested to see if reoperation rates were affected due to sex, laterality, bilateral involvement, family history, or associated syndromes.
METHODS A total of 60 thumbs in 54 patients were treated surgically for radial polydactyly from 2000 to 2010 at our institution. 2010 was chosen as the last year of our collection as all patients needed to have at least 2 years of potential follow-up. The authors categorized all surgical cases based on the classification system proposed by Chung and colleagues (Fig. 1), using the patient’s medical records and radiographs. The charts were reviewed for sex, laterality, bilateral involvement, a family history of duplication, and associated syndromes that were then documented. All charts were reviewed in their entirety to assess for any complications that arose and the need for reoperation. Statistical testing using w2 analysis was then used to look for any statistical significance between the groups. J Pediatr Orthop
Volume 36, Number 2, March 2016
Copyright r 2016 Wolters Kluwer Health, Inc. All rights reserved.
J Pediatr Orthop
Volume 36, Number 2, March 2016
Type 1 Joint type
Radial Polydactyly and the Incidence of Reoperation
Type 2: Single Epiphyseal type
Type 3: Osteochondroma type
Type 4: Hypoplastic type
FIGURE 1. Different types of thumb polydactyly. Type I: Each digit has its own joint at its origin. Type II: The origin of the duplicated digit arises from a common epiphysis. Type III: The origin of the duplicated digit resembles an osteochondroma. Type IV: The duplicated digit is attached by soft tissue alone. Adapted from Chung et al.8 Adaptations are themselves works protected by copyright. So in order to publish this adaptation, authorization must be obtained both from the owner of the copyright in the original work and from the owner of copyright in the translation or adaptation.
RESULTS A total of 60 duplicated thumbs in 54 patients (34 males and 20 females) underwent surgical intervention between 2000 and 2010. The mean age at the time of surgery was 1.3 years (range, 6.5 mo to 8 y 11 mo). Eight patients had an associated syndrome though no 1 syndrome was most prevalent. Of the 54 patients treated surgically, 8 patients had a family history of duplication for an overall rate of 14.8%. The results are listed in Tables 1 and 2. Of the 60 surgical radial polydactyly cases, a total of 8 cases underwent reoperation but only 6 were considered in our statistical analysis. The 2 cases that were excluded had returned to the operating room for a pin removal (that in every other case was performed in the clinic) and for an elective scar revision 5 years postoperatively. Of the 6 cases considered as true reoperations for our study, 3 were type I and 3 were type II for overall reoperation rates for types I and II of 8% and 50%, respectively. Reoperations were performed for radial collateral ligament instability, recurrent angular deformity at the MCP/
IP joint or nail-bed/nail-plate issues. No types III or IV required reoperation during our follow-up period. The reoperation rate overall was 10%. w2 statistical analysis showed no statistical significance (P > 0.05) between reoperation and sex (P = 0.536), family history (P = 0.830), syndrome association (P = 0.311), laterality (P = 0.928), and bilateral involvement (P = 0.389). Statistical significance was seen with the new classification system and reoperation rate (P = 0.005) where the reoperation rate was significantly higher in types I and II than III or IV.
DISCUSSION The Wassel classification system for radial polydactyly has remained the most used method for describing thumb duplications. Although it is useful for describing the level of duplication, the subgroups do not correlate with specific surgical approaches or postoperative outcomes. In fact, many of the Wassel groups have similar morphology and would require similar operative interventions (ie, Wassel 2-4-6 or Wassel 3-5).
TABLE 1. Chung and Colleagues Distribution Chung and Colleagues Classification Group I II III IV
Copyright
r
No. Cases
Total Cases (%)
No. Reoperations
Reoperation Rate (%)
37 6 6 11
62 10 10 18
3 3 0 0
8 50 0 0
2015 Wolters Kluwer Health, Inc. All rights reserved.
www.pedorthopaedics.com |
Copyright r 2016 Wolters Kluwer Health, Inc. All rights reserved.
159
J Pediatr Orthop
Evanson et al
Volume 36, Number 2, March 2016
TABLE 2. Wassel Distribution Wassel Group I II III IV V VI VII
No. Cases
Total Cases (%)
No. Reoperations
Reoperation Rate (%)
0 16 2 28 2 4 8
0 27 3 47 3 7 13
0 3 0 3 0 0 0
0 19 0 11 0 0 0
Chung et al8 proposed a new classification system with 4 unique subgroups. Our data indicate there was a statistically significant association between reoperation and the Chung and colleagues classification system typology (P = 0.005) but no other statistical significance between other variables. This information has important clinical implications. For example, for the child with a Chung Types I or II duplication, a more informative discussion can be held with the family about the potential need for revision surgery and the possibility of less than optimal surgical outcomes. In addition, it can guide the physician in terms of postoperative follow-up care. Types III and IV thumb duplications did not undergo any reoperations and therefore these thumbs could potentially require shorter postoperative follow-up periods. However, those with types I or II thumbs were found to have an increased potential for reoperation. Therefore, it can be inferred that these patients may need to be followed for a longer time period to monitor clinical parameters such as angulation deformity or joint instability. There are only a few studies looking at large cohorts of surgically treated radial polydactyly, but our distribution of subtypes and reoperation rates seem to be comparable to these. The present study’s distributions are listed in Tables 1 and 2 and the overall reoperation rate was 10%. Chung et al8 had distributions of type I being the most common with 50% (ours 62%), type II, 18% (ours 10%), type III, 20% (ours 10%), and type IV, 7% (ours 18%). No reoperation rate was given for their study. Tada et al5 operated on 94 primary thumbs with distributions using a modified Wassel system showing types II and IV to be the most common at 16% and 44%, respectively. Our distributions were similar with type II at 27% and type IV at 47%. No reoperation rate was given for their study but outcomes showed poor results in 4.3% and fair results in 20.2%.5 Ogino and colleagues operated on 113 thumbs with a modified Wassel classification system showing types II and IV to be the most common at 25% and 42%, respectively—very similar to ours. Their outcomes showed a poor result in 3.5% of cases and a fair result in 11%—their reoperation rate was 11.5%.3 Our study shows similar distributions and reoperation rates indicating this new classification system’s validity and usefulness.
160 | www.pedorthopaedics.com
The present study did have some limitations. The indications for reoperation were not based on any hard radiographic parameters but rather on the thumb’s clinical presentation. Although it would be helpful to define what the angular deformity was numerically, this would be extremely difficult as radiographs were not commonly ordered on all patients unless clinically warranted. Other patients requiring revision for ligamentous instability or nail deformity would not fall into this group either. In addition, while most patients remain within our hospital system for their care (and it was assumed that those patients not presenting complaining of issues or deformity had good results), we cannot rule out the possibility that some patients may have presented elsewhere requiring revision surgery. In conclusion, it is known that the Chung et al8 classification system provides an anatomic method to describe thumb duplication that can assist in planning surgical treatment. The data presented here support that this classification system also gives meaningful information in regard to the potential for revision surgery. Thus, using the Chung and colleagues system as the new standard for classifying radial polydactyly will not only aid in preoperative planning, but it can guide the physician in managing long-term patient care, and educating families about expected treatment outcomes. REFERENCES 1. Dobyns JH, Lipscomb PR, Cooney WP. Management of thumb duplication. Clin Orthop Relat Res. 1985;195:26–44. 2. Ezaki M. Radial polydactyly. Hand Clin. 1990;6:577–588. 3. Ogino T, Ishii S, Takahata S, et al. Long-term results of surgical treatment of thumb polydactyly. J Hand Surg Am. 1996;21:478–486. 4. Seidman GD, Wenner SM. Surgical treatment of the duplicated thumb. J Pediatr Orthop. 1993;13:660–662. 5. Tada K, Yonenobu K, Tsuyuguchi Y, et al. Duplication of the thumb. A retrospective review of two hundred and thirty-seven cases. J Bone Joint Surg. 1983;65A:584–598. 6. Wassel HD. The results of surgery for polydactyly of the thumb. A review. Clin Orthop Relat Res. 1969;64:175–193. 7. Manske PR, Oberg KC. Classification and developmental biology of congenital anomalies of the hand and upper extremity. J Bone Joint Surg. 2009;91(suppl 4):3–18. 8. Chung MS, Baek GH, Gong HS, et al. Radial polydactyly: proposal for a new classification system based on the 159 duplicated thumbs. J Pediatr Orthop. 2013;33:190–196.
Copyright
r
2015 Wolters Kluwer Health, Inc. All rights reserved.
Copyright r 2016 Wolters Kluwer Health, Inc. All rights reserved.
