Background:
Knowledge is limited about the diagnosis and treatment of modified Gartland type-IV supracondylar humeral fractures. We determined the prevalence of type-IV fractures, identified preoperative characteristics associated with these injuries, and assessed operative treatment characteristics.
Methods:
We retrospectively identified patients <16 years of age who underwent operative treatment of a supracondylar humeral fracture at 2 centers between 2008 and 2016. We compared patient, injury, and treatment characteristics between type-IV and type-III fracture groups (1:4, cases:controls). Preoperative radiographs were assessed by 4 pediatric orthopaedists blinded to fracture type. The odds of a fracture being type IV were assessed using univariate logistic regression for individual radiographic parameters. Significance was set at alpha = 0.05.
Results:
Type-IV fractures accounted for 39 (1.3%) of the supracondylar humeral fractures treated operatively during the study period. A type-IV fracture was associated with the following radiographic parameters: flexion angulation (odds ratio [OR] = 17; 95% confidence interval [CI] = 4.9 to 59), valgus angulation (OR = 5.6; 95% CI = 1.6 to 20), and lateral translation (OR = 4.1; 95% CI = 1.6 to 11) of the distal fragment; osseous apposition between the proximal and distal fragments (OR = 4.0; 95% CI = 1.8 to 9.0); and propagation of the fracture line toward the diaphysis of the proximal segment (OR = 9.2; 95% CI = 1.6 to 53). We found no significant differences in patient or injury characteristics between the groups. Compared with type-III fractures, type-IV fractures were treated more frequently with open reduction and percutaneous pinning (13% compared with 3.8%; p = 0.04) and were associated with longer mean operative time (82 ± 42 compared with 63 ± 28 minutes; p = 0.001).
Conclusions:
We identified 5 preoperative radiographic parameters associated with greater odds of a supracondylar humeral fracture being type IV rather than type III. No patient or injury characteristic differed significantly between the groups. Substantial overlap likely exists between type-IV and flexion-type fractures. Type-IV fractures were associated with longer operative time and were treated with open reduction more frequently than were type-III fractures.
Level of Evidence:
Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
Supracondylar humeral fractures are the most common elbow fracture in children1,2. They are grouped into extension and flexion types, according to the direction of anteroposterior displacement3. Most surgeons use the Wilkins modification4 of the Gartland classification5 to categorize pediatric extension-type supracondylar humeral fractures according to the degree of anteroposterior displacement of the distal fragment, as viewed on lateral radiographs (type I: nondisplaced; type II: displaced, with intact posterior cortical hinge; or type III: complete disruption of the posterior cortex)3. Type-III fractures are assumed to have an intact posterior periosteum that can aid in reduction maneuvers6. In 2006, Leitch et al.7 further modified the classification system to include a variant of type-III fractures with multidirectional instability resulting from circumferential loss of the periosteal hinge. This rarer fracture type is referred to as a modified Gartland type-IV fracture. Type-IV fractures are diagnosed in the operating room (during reduction attempt[s]/manipulation), where instability can be assessed without impediments to flexion or extension, as opposed to preoperative radiographic diagnosis, which is possible for fracture types I to III.
The standard treatment for type-III and type-IV supracondylar humeral fractures is closed reduction and percutaneous pinning (CRPP) or open reduction and percutaneous pinning (ORPP)8. Although type-III fractures are more common, type-IV fractures are often more difficult to reduce because of the instability caused by the loss of the anterior and posterior periosteal hinges7,9. There is scant literature describing the diagnosis and treatment of type-IV supracondylar humeral fractures.
The aims of this study were to determine the prevalence of type-IV fractures; identify preoperative patient, injury, and radiographic characteristics associated with these injuries; and assess operative treatment characteristics. The findings of this study will help surgical teams predict the likelihood of type-IV fracture, so they can more accurately counsel patients, anticipate operative time, and plan for the required surgical equipment for this rare, complex fracture type10.
Materials and Methods
Patient Selection
After receiving institutional review board approval for this retrospective review, we queried the patient databases of 2 institutions for all patients <16 years of age who underwent operative treatment for a modified Gartland type-III or type-IV supracondylar humeral fracture between 2008 and 2016, using Current Procedural Terminology and International Classification of Diseases, Ninth or Tenth Revision, Clinical Modification codes. Operative notes were screened, and fracture type was identified according to the surgeon’s diagnosis (type III or IV). We excluded patients who (1) had a history of skeletal dysplasia or endocrine disorder, (2) were missing preoperative/injury radiographs, (3) had undergone attempted fracture reduction in the emergency department, (4) had a transphyseal or adolescent intercondylar distal humeral fracture pattern, or (5) were missing intraoperative documentation of fracture type.
We selected a cohort of patients with modified Gartland type-III fractures (1:4 ratio of cases to such “controls”) using random sampling to compare with the type-IV fracture cohort.
Patient and Injury Characteristics
We determined patient age, sex, body mass index (BMI), and injury characteristics (laterality of injury, neurological injury, vascular injury, open fracture, ipsilateral forearm or wrist fracture, and compartment syndrome) by reviewing medical records.
Radiographic Parameters
Four fellowship-trained pediatric orthopaedic surgeons, blinded to fracture type, reviewed preoperative anteroposterior and lateral radiographs. Radiographic parameters assessed were (1) angulation of the distal fracture fragment in the sagittal plane (i.e., flexion or extension), (2) angulation of the distal fracture fragment in the coronal plane, (3) translation of the distal fracture fragment in the coronal plane, (4) osseous apposition (i.e., cortical contact) between of the proximal and distal fragments on anteroposterior and lateral radiographs, (5) propagation of the fracture line toward the diaphysis of the proximal segment, (6) fracture comminution, and (7) whether the fracture fragment abutted skin. For each patient, parameters were determined by consensus agreement rating.
Operative Characteristics
We reviewed patient records for operative treatment type (CRPP or ORPP) and operative time. Operative time was defined as the time from surgical “time-out” to “anesthesia stop.”
Statistical Analysis
Data were analyzed using chi-square tests or Fisher exact tests for categorical variables and 2-sample t tests or Mann-Whitney U tests for continuous variables. Interrater agreement on the assessment of radiographs was measured using the kappa (κ) statistic and categorized according to the method of Landis and Koch11. The likelihood of a type-IV fracture for each parameter was modeled using univariate logistic regression. Odds ratios (ORs) were estimated and are reported with their associated 95% confidence intervals (CIs). Significance was considered at α = 0.05 for all analyses. Analyses were performed using SPSS Statistics for Macintosh software (version 24.0; IBM) and Stata software (version 15; StataCorp).
Results
Thirty-nine children aged 3 to 13 years with a type-IV supracondylar humeral fracture were included. This reflected a prevalence of 1.2% (26 of 2,215) at 1 center, 1.6% (13 of 825) at the other center, and 1.3% overall among all operatively treated supracondylar humeral fractures during the study period. The 39 patients with a type-IV fracture were compared with the control cohort of 156 patients with a type-III fracture.
Patient and Injury Characteristics
There were no significant differences between type-III and type-IV fracture groups in terms of patient characteristics (age, sex, BMI) or injury characteristics (laterality of injury, neurological injury, vascular injury, open fracture, ipsilateral wrist or forearm fracture, compartment syndrome) (p > 0.05 for all) (Table I). No type-IV fractures were open injuries, and no patient with a type-IV fracture had compartment syndrome.
TABLE I.
Patient and Injury Characteristics of 195 Skeletally Immature Patients with a Type-III or IV Supracondylar Humeral Fracture
| Parameter | Type III (N = 156) | Type IV (N = 39) | P Value |
| Patient parameters | |||
| Age* (yr) | 6.4 ± 2.2 | 6.5 ± 2.4 | 0.96 |
| Female sex (no. [%]) | 70 (45) | 20 (51) | 0.47 |
| BMI* (kg/m2) | 16 ± 3.1 | 17 ± 3.3 | 0.35 |
| Injury parameters (no. [%]) | |||
| Left side | 99 (63) | 28 (72) | 0.33 |
| Neurological injury | 18 (12) | 9 (23) | 0.06 |
| Ipsilateral forearm or wrist fracture | 8 (5.1) | 1 (2.6) | 0.43 |
| Open fracture | 6 (3.8) | 0 (0) | 0.26 |
| Vascular injury | 5 (3.2) | 2 (5.1) | 0.43 |
| Compartment syndrome | 2 (1.3) | 0 (0) | 0.64 |
The values are given as the mean and standard deviation.
Radiographic Characteristics
One patient with a type-IV fracture was excluded from radiographic analyses because the preoperative lateral radiograph was missing. This left 194 fractures for analysis (156 type-III and 38 type-IV fractures).
Diagnosis of type-IV fracture was significantly more likely given the presence of the following: flexion angulation of the distal fragment (OR = 17; 95% CI = 4.9 to 59), valgus angulation of the distal fragment (OR = 5.6; 95% CI = 1.6 to 20), lateral translation of the distal fragment (OR = 4.1; 95% CI = 1.6 to 11), osseous apposition (cortical contact) between the proximal and distal fragments (OR = 4.0; 95% CI = 1.8 to 9.0), or fracture propagation toward the diaphysis (OR = 9.2; 95% CI = 1.6 to 53) (Table II). There were no significant associations with comminution or whether the fracture fragment was abutting the skin.
TABLE II.
Univariate Odds of Supracondylar Humeral Fractures Being Type IV (N = 38) Versus Type III (N = 156) on the Basis of Preoperative Radiographic Parameters*
| Parameter | OR (95% CI) | P Value |
| Angulation of distal fragment in sagittal plane | ||
| Extension | Referent | Referent |
| Flexion | 17 (4.9-59) | <0.001 |
| Neutral | 3.4 (0.3-39) | 0.33 |
| Angulation of distal fragment in coronal plane | ||
| Varus | Referent | Referent |
| Valgus | 5.6 (1.6-20) | 0.008 |
| Neutral | 2.3 (0.6-9.3) | 0.24 |
| Translation of distal fragment in coronal plane | ||
| Medial | Referent | Referent |
| Lateral | 4.1 (1.6-11) | 0.004 |
| None | 1.9 (0.7-5.5) | 0.25 |
| Osseous apposition between proximal and distal fragments | ||
| Absent | Referent | Referent |
| Present | 4.0 (1.8-9.0) | 0.001 |
| Propagation of fracture line toward diaphysis of proximal segment | ||
| Absent | Referent | Referent |
| Present | 9.2 (1.6-53) | 0.01 |
| Comminution | ||
| Absent | Referent | Referent |
| Present | 1.8 (0.7-4.5) | 0.22 |
| Fracture fragment abutting the skin | ||
| Absent | Referent | Referent |
| Present | 0.8 (0.3-2.1) | 0.63 |
OR = odds ratio, and CI = confidence interval.
Among type-IV fractures, there was flexion angulation of the distal fragment in 30% (versus 3% in type-III fractures), valgus angulation of the distal fragment in 66% (versus 40% in type-III fractures), lateral translation of the distal fragment in 69% (versus 41% in type-III fractures), osseous apposition in 64% (versus 32% in type-III fractures), and fracture propagation toward the diaphysis in 11% (versus 1% in type-III fractures).
Interobserver agreement on radiographic parameters was substantial for translation of the distal fragment in the coronal plane (κ = 0.76); moderate for the fracture fragment abutting the skin (κ = 0.53), angulation of the distal fragment in the sagittal plane (κ = 0.53), osseous apposition between proximal and distal fragments (κ = 0.44), and angulation of the distal fragment in the coronal plane (κ = 0.44); fair for fracture propagation toward the diaphysis (κ = 0.24); and slight for comminution (κ = 0.11) (see Appendix). Significant radiographic parameters, the prevalence of each parameter in the type-IV fracture cohort, and associated representative images of each parameter are presented in Figure 1.
Fig. 1.
Significant radiographic parameters with at least moderate interobserver agreement, their prevalence in the type-IV cohort, and representative images. The images of flexion angulation, lateral translation, and valgus angulation are from 2 patients each. The images of osseous apposition are anteroposterior and lateral views of the same patient.
Operative Characteristics
The groups differed significantly by treatment type (Table III). ORPP was performed for a greater percentage of type-IV fractures compared with type-III fractures (p = 0.042). This difference was even more pronounced when comparing only closed fractures (p = 0.009). The mean operative time (and standard deviation) was significantly longer for all type-IV fractures (82 ± 42 minutes) compared with type-III fractures (63 ± 28 minutes) (p = 0.001).
TABLE III.
Operative Parameters for Skeletally Immature Patients with Type-III or IV Supracondylar Humeral Fractures*
| Parameter | Type-III Fracture | Type-IV Fracture | P Value |
| All fractures† (no. [%]) | |||
| Treatment type | 0.042 | ||
| CRPP | 150 (96) | 33 (87) | |
| ORPP | 6 (3.8) | 5 (13) | |
| Operative time‡ (min) | 63 ± 28 | 82 ± 42 | 0.001 |
| Closed fractures§ (no. [%]) | |||
| Treatment type | 0.009 | ||
| CRPP | 147 (98) | 33 (87) | |
| ORPP | 3 (2.0) | 5 (13) | |
| Operative time‡ (min) | 64 ± 28 | 82 ± 42 | 0.002 |
CRPP = closed reduction and percutaneous pinning, and ORPP = open reduction and percutaneous pinning.
Includes 156 type-III fractures and 38 type-IV fractures.
The values are given as the mean and standard deviation.
Includes 150 type-III fractures and 38 type-IV fractures.
Discussion
We identified preoperative radiographic parameters associated with greater odds of a supracondylar humeral fracture being a type-IV rather than a type-III fracture, but we found no patient factors associated with the diagnosis. In 2006, Leitch et al.7 first described a multidirectionally unstable supracondylar humeral fracture variant, in 9 patients. The authors referred to this as the modified Gartland type-IV fracture. In our study, the proportion of type-IV supracondylar humeral fractures treated was relatively small, at only 1.3% of all operatively treated supracondylar humeral fractures during the study period. To our knowledge, this represents the largest cohort of type-IV supracondylar humeral fractures reported to date, which also highlights the rarity of this injury.
Given the rarity of type-IV supracondylar humeral fractures, determining the true rate of injury is challenging, with reports ranging from 3% to 9%7,12 of all operatively treated supracondylar humeral fractures. The variability in frequency of type-IV fractures reported is likely the result of several factors. The diagnosis of type-IV fractures is only possible intraoperatively (during reduction attempt[s]/manipulation in the operating room), and the inter- and intrarater reliabilities of the diagnosis are unknown. Diagnosis is a subjective matter that is ultimately decided by the treating surgeon. A type-IV fracture may be caused iatrogenically during reduction attempt(s) in the operating room7, further confounding the diagnosis and rates of occurrence.
Reported rates of neurological injury sustained by patients with type-IV supracondylar humeral fractures vary widely, from 0% to 36%6,7,9,13. These rates are comparable with the 23% of patients with at least 1 nerve palsy in our study. Furthermore, there was no significant difference in the rate of neurological injury between type-III and type-IV fractures (p = 0.059), which is also consistent with published comparative data6,13. Also consistent with previous data, there were no differences in patient or injury characteristics between the 2 fracture types6,7.
No preoperative clinical factors were associated with type-IV supracondylar humeral fractures. However, we identified several radiographic parameters that were associated with type-IV fractures on the basis of significantly elevated ORs and prevalence in ≥30% of type-IV fractures. The most strongly associated parameter was flexion angulation of the distal fragment, followed by valgus angulation, lateral translation, and the presence of osseous apposition between the proximal and distal fracture fragments. It is likely that substantial overlap exists between type-IV and flexion-type fractures. Although not all type-IV fractures are flexion-type variants and not all flexion-type fractures are multidirectionally unstable, our findings suggest that there is substantial overlap between these 2 rare fracture types.
Regarding operative characteristics, the longer operative times and higher frequency of ORPP for type-IV fractures compared with type-III fractures are consistent with previous data from the largest, to our knowledge, available series6. However, other groups with smaller sample sizes of type-IV fractures (7 or 8 cases) reported success with CRPP in all cases7,9. Even in our large cohort of type-IV fractures, ORPP was still a relatively rare occurrence, at only 13% (n = 5), which may explain why ORPP was not observed in the smaller series. Our rate of ORPP for type-IV fractures was even higher than that noted for type-III fractures when comparing only closed fractures; half of the type-III fractures that underwent ORPP (3 of 6) were open fractures, which likely necessitated an open approach for irrigation and debridement and not necessarily because of the difficulty of fracture reduction.
Our study had several limitations, including those inherent in a multicenter, retrospective review, such as heterogeneity in patient population and incomplete or inaccurate data. Additionally, there are limitations related to studying type-IV supracondylar humeral fractures because of the lack of an objective, “gold standard” diagnostic test. The interrater reliability results were variable, ranging from substantial for 1 parameter to only slight for another parameter, but most parameters had moderate agreement. Nonetheless, several factors were statistically more likely to be associated with a diagnosis of type-IV rather than type-III supracondylar humeral fracture. It is important to note that the κ statistic is influenced by the prevalence of a given factor or variable being considered14. When prevalence is low, as with propagation of the fracture fragment toward the diaphysis, low κ values do not necessarily reflect poor overall agreement. Lastly, a multivariable regression model could not be supported with the current data because of the small sample size of this rare clinical entity. The translation to other centers and the generalizability of our findings cannot be confirmed because of this limitation.
Despite these limitations, this study had several strengths. To our knowledge, this is the largest series of type-IV supracondylar humeral fractures and the first study to identify preoperative factors associated with type-IV supracondylar humeral fracture. Radiographic parameters were determined by consensus of 4 fellowship-trained observers, increasing the generalizability compared with a single-observer approach.
In conclusion, we identified several preoperative radiographic factors that were associated with type-IV supracondylar humeral fracture. Preoperative identification of this rare fracture type would allow for improved preoperative planning (e.g., anticipation of longer operative time, higher likelihood of ORPP) and more accurate counseling of patients and their families about the likelihood of open reduction when a type-IV fracture is suspected.
Appendix
Supporting material provided by the authors is posted with the online version of this article as a data supplement at jbjs.org (http://links.lww.com/JBJS/F362).
Acknowledgments
Note: The authors acknowledge the contributions of Cheryl Lawing, MD, for the initial project conceptualization and imaging review and Richard L. Skolasky, ScD, for data management and conceptualization of the statistical analysis. Additionally, the authors thank Rachel Box, MS, and Jenni Weems, MS, for their editorial assistance and help preparing the manuscript for submission.
Footnotes
Disclosure: This study was supported in part by a T32 grant (AR067708) from the National Institutes of Health. On the Disclosure of Potential Conflicts of Interest forms, which are provided with the online version of the article, one or more of the authors checked “yes” to indicate that the author had a relevant financial relationship in the biomedical arena outside the submitted work (http://links.lww.com/JBJS/F361).
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