Ankle fractures are among the most common injuries treated by orthopedic surgeons, with an annual incidence of as high as 187 per 100,000 persons in the United States.1,2 Traditionally, these fractures have been treated with a lag screw and neutralization plate technique, most commonly with a one-third tubular plate, although more recently, the use of contoured locking plates has increased.3,4 The past decade has seen a significant increase in the use of locking plates for fracture fixation, including distal fibula fractures.5,6 At the study institution alone, the use of contoured locking plates compared with one-third tubular plates nearly doubled during the study period.
Biomechanical studies comparing locking and nonlocking plates for the treatment of distal fibula fractures showed greater strength of locking plates in the setting of comminuted fractures and osteoporotic bone, but no advantage of locking plates for fractures amenable to lag screw fixation.7–13 The few clinical studies comparing locking and nonlocking plates have shown no improvement of outcomes or radiographic parameters with the use of locking plates.11,14,15 Authors have cited concern about inadequate distal fixation with traditional plates because of the small size of the distal fracture fragment and the need for unicortical screws to avoid intraarticular placement in the distal fibula.4,16 Despite concerns about inadequate fixation with conventional plating techniques for the distal fibula, however, no studies have clearly shown a true risk of fibular implant failure.
The use of locking plates also carries an increased cost, and in the increasingly economically conscious health care setting, the orthopedic surgeon plays an important role in limiting unnecessary expenditure.15 To the authors' knowledge, no study has reported an analysis of implant costs with various locking and conventional plates used for distal fibula fractures. The primary goal of the current study was to evaluate the risk of lateral implant failure with the use of contoured locking and conventional one-third tubular plates. A secondary goal was to evaluate the rates of complications and removal of implants and the associated patient risk factors. Finally, the study performed a cost analysis of typical locking and nonlocking plate constructs. The study hypothesis was that contoured distal fibular locking plates are overused and that implant failure in lateral ankle fixation does not occur, regardless of the plate type or the extent of distal fragment fixation.
Materials and Methods
This study was approved by the internal institutional review board at the study institution. The orthopedic surgical case records at a single level I trauma center were reviewed to identify all patients who were treated with internal fixation of lateral malleolar fractures between 2010 and 2013. The electronic medical record (including operative notes and radiographs) was reviewed retrospectively. Patient demographics, body mass index, medical comorbidities (including diabetes with and without peripheral neuropathy), smoking status, and type of fracture according to the Orthopaedic Trauma Association (OTA) classification were recorded. Treatment-related variables, including type of surgical implant, surgical delay, intraoperative findings and complications, and time to latest follow-up, were recorded.
Patients who were 18 years or older and had a transsyndesmotic lateral malleolar fracture, whether isolated or with concomitant medial and/or posterior malleolar fractures (OTA types 44-B1, -B2, and -B3), treated with internal plate fixation, and with at least 1 series of postoperative ankle radiographs at 4 weeks or more from the time of surgery were included. The rationale for including these patients was to examine fracture patterns that required a lateral buttress to talar translation in the setting where fixation distal to the fracture is a common concern. For OTA type 44-C fractures, there is regularly sufficient bone distal to the fibula fracture to allow for screw fixation. For OTA type 44-A fractures, these fibular fractures often do not require fixation when in isolation. When they are addressed in supination-adduction injuries, the concern is generally medial translation and not lateral translation of the talus.
Lateral malleolar fractures classified as OTA type 44-A or 44-C, those treated with syndesmotic or lag screws only, and distal fibula fractures associated with distal tibial shaft fractures were excluded.
All patients underwent closed reduction with placement of a short leg splint or cast at initial evaluation. Chief residents, under supervision of the attending faculty, performed all surgical procedures. Postoperatively, patients were placed in short leg splints, with transition to a short leg cast or controlled ankle motion boot at the first follow-up visit. All patients were instructed to be non-weight bearing for 4 to 8 weeks, depending on the clinical circumstances. Standard follow-up visits were at 2 weeks for wound check and at 4 weeks for the first postoperative radiographs, with subsequent visits based on the clinical course.
Surgical fixation of the lateral malleolus was performed with a standard direct lateral or posterior approach to the distal fibula, based on surgeon preference. Interfragmentary lag screw fixation with a neutralization plate was used with amenable fracture patterns, and the choice of plate was based on surgeon preference. The Figure shows typical examples of conventional and contoured locked plate constructs used in the study group. The one-third tubular plates (Small Fragment Set; Synthes Inc, Paoli, Pennsylvania) were compatible with locking screws, and locking screws were used for occasional cases, based on surgeon preference, primarily for unicortical screws in the distal fracture fragment. Most of the contoured locking plates that were used were distal fibular locking plates (Synthes Inc); however, for several cases, other comparable plates were used, including the complex fibular fracture plate (Arthrex Inc, Naples, Florida) and Peri-Loc VLP lateral and posterolateral fibula plates (Smith & Nephew, Cordova, Tennessee).
Preoperative and 12-week postoperative anteroposterior mortise ankle radiographs of similar lateral malleolar fractures, both with a single interfragmentary lag screw and with neutralization plates of comparable lengths. Treated with a conventional one-third tubular plate (A). Treated with a contoured distal fibular locking plate and locking distal fragment screws (B).
The primary study outcomes were failure of the distal fibular implant and loss of reduction, as assessed radiographically and from medical records. Implant failure was defined as gross deformation of the plate or pullout of distal screw fixation. Loss of reduction was defined as displacement of the fracture of greater than 2 mm on at least 1 postoperative radiograph compared with initial postoperative films. Secondary outcomes included deep infection of the lateral surgical wound and surgery for revision of fixation or removal of implants to treat persistent implant-related symptoms or infection. Only deep infections that were refractory to antibiotic therapy alone and were treated surgically by wound debridement, with or without removal of implants, were recorded.
Statistical analysis was performed with SPSS version 22.0 software (SPSS, Chicago, Illinois). Descriptive analyses of baseline patient characteristics and treatment outcomes for each group were performed. Fisher's exact test and Pearson's chi-square analysis were used to compare categorical variables, and Student's t test was used for continuous variables. Statistical significance was set at P<.05. Numeric data were expressed as mean and standard deviation, except for length of follow-up, which was expressed as median with 25th to 75th percentile values. Nominal and ordinal data were shown as numbers with percentages.
Univariate analyses of the entire study group were performed to identify associations between patient characteristics and risk of wound infection or implant removal. The use of a contoured locking or conventional one-third tubular plate as an independent variable and significant variables from univariate analyses were then analyzed via multivariate regression modeling to adjust for confounding. P<.05 was set as the level of statistical significance.
Between May 2010 and April 2013, 464 adults underwent surgical treatment for ankle injuries involving fractures of the lateral malleolus. Of these injuries, 127 were suprasyndesmotic fractures (OTA type 44-C) and were excluded from the study. An additional 337 were transsyndesmotic fractures (OTA type 44-B), and of these, 7 patients were excluded because of treatment with implants other than a plate (2 received lag screws only, 3 received tibiotalar pins, 1 received an external fixator, and 1 received a distal fibulectomy). The remaining 330 patients were treated with plates, 228 with one-third tubular plates and 102 with contoured locking plates. In addition, 6 patients in the one-third tubular plate group and 5 patients in the contoured locking plate group had less than 4 weeks of postoperative follow-up and were not included in the analysis. The 319 remaining patients were included in the final study population, 222 in the one-third tubular plate group and 97 in the contoured locking plate group. Descriptive statistics for the baseline characteristics of the contoured locking plate group and the one-third tubular plate group are shown in Table 1. The 2 groups had similar body mass index, history of diabetes, surgical delay, and length of follow-up. Compared with the one-third tubular plate group, patients in the contoured locking plate group were significantly older, 44.4 years (SD, 13.3 years) vs 37.9 years (SD, 13.1 years) (P=.0001); included more women, 60.1% vs 37.4% (P=.0001); and had slightly less history of smoking, 16.5% vs 27.2% (P=.04). The number of open fractures and the use of syndesmotic fixation were similar for the 2 groups. Lag screw fixation was used significantly less in the contoured locking plate group compared with the one-third tubular plate group (56.7% vs 92.8%, respectively).
Demographic Data and Baseline Characteristics
A summary of measured outcomes for the one-third tubular plate group and the contoured locking plate group is shown in Table 2. No isolated failures of the lateral plates or loss of distal fibular fixation occurred in either group. Among the entire study group, 5 (1.6%) patients underwent revision of fixation to revise or add syndesmotic fixation because of loss of initial syndesmotic reduction or failure to recognize and treat syndesmotic injury at initial surgery. Of these syndesmotic revisions, 4 occurred in the one-third tubular plate group and 1 occurred in the contoured locking plate group. However, the difference was not statistically significant (P=.610). For the entire study group, the rates of deep infection and removal of lateral implants were 2.8% and 4.4%, respectively; both of these occurred significantly more among the contoured locking plate group compared with the one-third tubular plate group. Rates of infection in the contoured locking plate group and the one-third tubular plate group were 6.2% and 1.4%, respectively (P=.017). Rates of lateral implant removal in the contoured locking plate group and the one-third tubular plate group were 9.3% and 2.3%, respectively (P=.005).
Outcomes for the One-Third Tubular and Contoured Locking Plate Groups
Univariate analysis of the entire study group showed significant associations between infection and implant removal with older age, a history of diabetes, higher body mass index, and the use of a locked plate (data not shown). After adjustment for age, diabetes, and body mass index as potential confounders, on multivariate analysis, the associations between use of a contoured locking plate and infection or implant removal were no longer statistically significant.
Epidemiologic data on adult ankle fractures report annual incidences of up to 187 per 100,000 persons. Of these ankle fractures, 80% include lateral malleolar fractures, and 76% of these fractures are treated with surgical fixation.17,18 Data from the 2010 census showed a US adult population of 235 million.19 The authors used a conservative value for annual incidence of 0.1% and calculated that approximately 180,000 Weber B lateral malleolar fractures are treated surgically in the United States each year. Based on an estimate that contoured locking plates are used for one-third of these cases, with a conservatively calculated additional implant cost of $800 per case, the potential avoided annual cost is $50 million nationally (Table 3). This estimated avoided cost does not include additional costs associated with complications.
Cost Breakdown of Distal Fibular Plate Constructs
To the authors' knowledge, no study has compared implant failure rates between conventional one-third tubular and contoured locking plates for fixation of Weber B fractures of the lateral malleolus. A substantial increase in the use of contoured locking plates occurred at the study institution during the study period. Despite this shift, no evidence suggested a clinical need to support the use of different types of fixation because no failures of conventional constructs occurred during the study period. The failures that occurred were all related to inadequate treatment of associated syndesmotic injuries and not to fixation of the distal fracture fragment. The authors suggest alternative fixation strategies to increase the strength of lateral fixation when needed for comminuted or osteopenic bone, namely, the use of tetracortical fibular-tibial (syndesmotic) screw fixation through the lateral plate. This approach reinforces the primary utility of the plate to act as a lateral buttress to prevent lateral displacement of the talus and distal fibula fracture fragment and has been reported as biomechanically effective in several studies.20–22 Additionally, unicortical locking screws may be used with a one-third tubular plate to create a fixed-angle device. Kim et al23 reported mechanical equivalence with only 2 unicortical distal locking screws compared with 3 nonlocking unicortical screws, independent of bone mineral density.
In the only prospective randomized controlled trial comparing the use of locking and nonlocking constructs for distal fibula fractures, Tsukada et al14 found no difference for time to union or time to resolution of postoperative pain, and no implant failures occurred in either group. That study was similar to the current study in that it included only Weber B fractures and included patients of similar ages (mean age, locking group, 40.7 years; nonlocking group, 41.7 years). Although the plates used in the study of Tsukada et al14 were slightly different from those used in the current study, their finding of the adequacy of fracture fixation and complete lack of implant failure with nonlocking plates with only 2 cortices of fixation in the distal fragment supports the ultimate claim of the current study.
Schepers et al6 showed increased risk of wound complications with locking plates, suggesting differences in plate profile as a potential explanation. The contoured locking plate that was used most commonly in the current study is wider and significantly thicker in profile than a one-third tubular plate. As a result, obtaining desirable soft tissue closure over the plate is more difficult surgically, and the plate is more noticeable to patients, even those with higher body mass index. The larger width of the contoured locking plates distally also places the posterior edge of the plate in closer proximity to peroneal tendons, which course just posteriorly to the lateral malleolus.
In addition to lack of support for a clinical benefit and the potential for increased complications, contoured locking plates carry an increased implant cost. A recent cost analysis of operative complications for ankle fractures showed that additional complications carry their own substantial costs.24 As noted earlier, the contoured locking plate, which is already more expensive than the one-third tubular plate, had higher rates of infection and lateral implant removal, both of which add even more cost to the overall care of the patient.
Limitations of the current study include limited or no follow-up for many patients and the lack of qualitative clinical or quantitative functional outcomes. These are inherent difficulties associated with any retrospective study that is performed at a large urban trauma center, where most of the population is of lower socioeconomic status. It is the authors' experience that patients of lower socioeconomic status have a more difficult time with transportation to their facility, making follow-up at regular intervals difficult. Another limitation of the study is that it did not examine the effect of posterior or lateral approaches on outcomes. Strengths of the current study include the large number of consecutive cases and the variety of clinical scenarios in which fixation was used without showing a clear benefit for contoured locking plates.
The selection bias for older women among the group treated with contoured locking plates cannot be ignored. Differences between the groups may be a proxy for situations in which the locking plates were chosen, including older patients, those with poor bone quality, and those with comminution. Although this may represent understandable clinical decision making, the lack of failures observed with either type of plate in such a great number of cases suggests an overvaluing of these factors. Further studies with improved design to account for this potential selection bias are needed.
The use of contoured locking plates for the treatment of Weber B distal fibular fractures has increased and is associated with significantly increased costs. This study showed that this increased use is unsubstantiated by outcomes because no lateral plate failures occurred in either the locking plate group or the one-third tubular plate group.
- Daly PJ, Fitzgerald RH Jr, Melton LJ, Ilstrup DM. Epidemiology of ankle fractures in Rochester, Minnesota. Acta Orthop Scand. 1987; 58(5):539–544. doi:10.3109/17453678709146395 [CrossRef]
- Donken CC, Al-Khateeb H, Verhofstad MH, van Laarhoven CJ. Surgical versus conservative interventions for treating ankle fractures in adults. Cochrane Database Syst Rev.2012; 8:CD008470.
- Beauchamp CG, Clay NR, Thexton PW. Displaced ankle fractures in patients over 50 years of age. J Bone Joint Surg Br. 1983; 65(3):329–332.
- Hughes JL, Weber H, Willenegger H, Kuner EH. Evaluation of ankle fractures: non-operative and operative treatment. Clin Orthop Relat Res. 1979; 138:111–119.
- Anglen J, Kyle RF, Marsh JL, et al. Locking plates for extremity fractures. J Am Acad Orthop Surg. 2009; 17(7):465–472. doi:10.5435/00124635-200907000-00007 [CrossRef]
- Schepers T, Van Lieshout EM, De Vries MR, Van der Elst M. Increased rates of wound complications with locking plates in distal fibular fractures. Injury. 2011; 42(10):1125–1129. doi:10.1016/j.injury.2011.01.009 [CrossRef]
- Lo EY, Tseng SS, Christiansen BA, Lee MA, Yoo BJ. Locking versus nonlocking construct in an osteoporotic, segmental fibula defect model. Orthopedics. 2013; 36(10):e1262–e1268. doi:10.3928/01477447-20130920-17 [CrossRef]
- Bariteau JT, Blankenhorn BD, Lareau CR, Paller DJ, DiGiovanni CW. Biomechanical evaluation of mini-fragment hardware for supination external rotation fractures of the distal fibula. Foot Ankle Spec. 2013; 6(2):88–93. doi:10.1177/1938640013477130 [CrossRef]
- Bariteau JT, Fantry A, Blankenhorn B, Lareau C, Paller D, Digiovanni CW. A biomechanical evaluation of locked plating for distal fibula fractures in an osteoporotic sawbone model. Foot Ankle Surg. 2014; 20(1):44–47. doi:10.1016/j.fas.2013.10.004 [CrossRef]
- White NJ, Corr DT, Wagg JP, Lorincz C, Buckley RE. Locked plate fixation of the comminuted distal fibula: a biomechanical study. Can J Surg. 2013; 56(1):35–40. doi:10.1503/cjs.012311 [CrossRef]
- Takemoto RC, Sugi MT, Kummer F, Koval KJ, Egol KA. The effects of locked and unlocked neutralization plates on load bearing of fractures fixed with a lag screw. J Orthop Trauma. 2012; 26(9):519–522. doi:10.1097/BOT.0b013e31823b3dd1 [CrossRef]
- Zahn RK, Frey S, Jakubietz RG, et al. A contoured locking plate for distal fibular fractures in osteoporotic bone: a biomechanical cadaver study. Injury. 2012; 43(6):718–725. doi:10.1016/j.injury.2011.07.009 [CrossRef]
- Davis AT, Israel H, Cannada LK, Bledsoe JG. A biomechanical comparison of one-third tubular plates versus periarticular plates for fixation of osteoporotic distal fibula fractures. J Orthop Trauma. 2013; 27(9):e201–e207. doi:10.1097/BOT.0b013e318281a565 [CrossRef]
- Tsukada S, Otsuji M, Shiozaki A, et al. Locking versus non-locking neutralization plates for treatment of lateral malleolar fractures: a randomized controlled trial. Int Orthop. 2013; 37(12):2451–2456. doi:10.1007/s00264-013-2109-9 [CrossRef]
- Egol KA, Capriccioso CE, Konda SR, et al. Cost-effective trauma implant selection: AAOS exhibit selection. J Bone Joint Surg Am. 2014; 96(22):e189. doi:10.2106/JBJS.N.00514 [CrossRef]
- Brown OL, Dirschl DR, Obremskey WT. Incidence of hardware-related pain and its effect on functional outcomes after open reduction and internal fixation of ankle fractures. J Orthop Trauma. 2001; 15(4):271–274. doi:10.1097/00005131-200105000-00006 [CrossRef]
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- Thur CK, Edgren G, Jansson KÅ, Wretenberg P. Epidemiology of adult ankle fractures in Sweden between 1987 and 2004: a population-based study of 91,410 Swedish inpatients. Acta Orthop. 2012; 83(3):276–281. doi:10.3109/17453674.2012.672091 [CrossRef]
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- Milner BF, Mercer D, Firoozbakhsh K, Larsen K, DeCoster TA, Miller RA. Bicortical screw fixation of distal fibula fractures with a lateral plate: an anatomic and biomechanical study of a new technique. J Foot Ankle Surg. 2007; 46(5) 341–347. doi:10.1053/j.jfas.2007.05.004 [CrossRef]
- Koval KJ, Petraco DM, Kummer FJ, Bharam S. A new technique for complex fibula fracture fixation in the elderly: a clinical and biomechanical evaluation. J Orthop Trauma. 1997; 11(1):28–33. doi:10.1097/00005131-199701000-00007 [CrossRef]
- Panchbhavi VK, Vallurupalli S, Morris R. Comparison of augmentation methods for internal fixation of osteoporotic ankle fractures. Foot Ankle Int. 2009; 30(7):696–703. doi:10.3113/FAI.2009.0696 [CrossRef]
- Kim T, Ayturk UM, Haskell A, Miclau T, Puttlitz CM. Fixation of osteoporotic distal fibula fractures: a biomechanical comparison of locking versus conventional plates. J Foot Ankle Surg. 2007; 46(1):2–6. doi:10.1053/j.jfas.2006.09.009 [CrossRef]
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Demographic Data and Baseline Characteristics
||One-Third Tubular Plate (222 Patients)
||Contoured Locking Plate (97 Patients)
|Age, mean (SD), y
|Body mass index,b mean (SD), kg/m2
|Time to surgery, mean (SD), d
|Length of follow-up, mean (SD), wk
| Median (25th–75th percentile)
Outcomes for the One-Third Tubular and Contoured Locking Plate Groups
||One-Third Tubular Plate
||Contoured Locking Plate
|Failure/revision (No./Total No.)a
|Infection (No./Total No.)
|Implant removal (No./Total No.)b
| Symptomatic implant, No./Total No.
| Infection, No./Total No.
Cost Breakdown of Distal Fibular Plate Constructs
||1 (one-third tubular) at $166 each
||1 (fibular locking) at $585 each
||1 (nonlocking) at $21 each
||1 (nonlocking) at $21 each
||3 (nonlocking) at $21 each
||3 (nonlocking) at $21 each
||2 (nonlocking) at $21 each
||4 (locking) at $110 each