Abstract
Background
Ankle fractures are a common type of fracture. Knowledge of functional outcomes are important for patient counseling and expectation management. The aim of this study is to evaluate the functional outcome after surgically treated ankle fractures and which patient, fracture and treatment characteristics are related to the midterm functional outcome after surgical fixation of ankle fractures.
Methods
Between August 2016 and May 2020, patients who were surgically treated for an ankle fracture in one of four participating hospitals were included. Patient, fracture and treatment characteristics were retrieved from medical records. After medical follow-up, patients were questioned about their functional outcome using the Lower Extremity Functional Scale (LEFS) questionnaire. Predictive factors for functional outcome were calculated by doing a linear regression analysis using SPSS.
Results
A total of 552 patients were included in this study. The median follow-up time was 2.3 years (IQR 544–1116 days) after injury, with a median LEFS of 66.40 (53.60–75.20) points. Fracture characteristics (Weber classification or Gustilo classification) were not seen as a significant predictor for the LEFS. Higher age, higher BMI, higher ASA classification, trimalleolar fixation and complications were found to be significant independent predictors of lower LEFS.
Conclusion
Two years after a surgically treated ankle fracture fewer than 25 % of the patients achieve the median functional score observed in the healthy Dutch population. In this study age, BMI, ASA classification, extensive surgical fixation and postoperative complications are the most important significant independent predictors of a lower functional outcome.
Level of Evidence
3
1
Introduction
Ankle fractures are a highly prevalent type of fracture of the lower extremity. ,,,, The largest age-specific incidence has been seen in men from 16 to 36 years old and women between 75 and 85 years old and nearly half of all fractures is treated surgically. ,
The aim of surgical treatment of ankle fractures is anatomical reconstruction, and thus protect injured (ligamentous) structures of the joint surface to enable early postoperative functional therapy of the joint. , That said, recovery of patients with an ankle fracture is initially rapid but slows over time, with the majority of the patients continuing to report symptoms and therefore functional limitations one year after surgical treatment. , Studying functional outcomes highlights the need of using patient-reported outcome measures (PROMs). The last decades, the use of PROMs have increased and are offering insight into patients’ perspectives by self-completion of questionnaires to ascertain patients’ views of their symptoms, their functional status, and their health related quality of life. Different factors are studied to influence functional outcomes in patients after an ankle fracture by using these PROMs. However, literature about midterm functional outcomes after surgically treated ankle fractures in Europe remains scarce.
It is of interest to know which factors are related to functional limitations for patient counseling, given the fact that these functional limitations contribute to patients health related quality of life. Therefore, the aim of this study is to evaluate the functional outcome using the Lower Extremity Functional Scale (LEFS) after surgically treated ankle fractures and to evaluate which patient, fracture and treatment characteristics are related to the midterm functional outcome after surgical fixation of ankle fractures.
2
Methods
2.1
Study design
This study used a database of patients who underwent treatment for an ankle fracture between 1st August 2016 and 31st April 2020. The participating hospitals included two level 1 trauma centers and two level 2 trauma centers in the Netherlands, all teaching hospitals. The database included all patients aged 18 years and older with ankle fractures treated at one of the participating hospitals. Data regarding patient, fracture and treatment characteristics were retrieved from medical records. Ethical approval was obtained from the local medical ethics committees.
2.2
Study variables
Patient characteristics included were age, sex, body-mass index (BMI) and the American Society of Anesthesiologists (ASA) classification. Fractures were classified using the Weber and Lauge-Hansen classification, the Gustilo classification was used for compound fractures. ,, Fractures were classified by medical researchers, in case of uncertainty one of three trauma surgeons of the research group was consulted.
Data on fracture fixation type, postoperative cast immobilization, and postoperative complications were extracted from the medical records. Operative fixation is described as uni-, bi- or trimalleolar, other fixation types such as an external fixator are described as ‘other’. Postoperative complications included infections, peripheral nerve damage, bleeding, malunion, nonunion, failure of osteosynthesis material and revision surgery. Infections were specified as superficial or deep wound infections. Superficial wound infections were defined as treated with oral antibiotics only. Wound infections treated with intravenous antibiotics and/or surgical debridement were defined as deep infections. Peripheral nerve damage was defined as the loss of sensibility in the ankle or foot persisting for three months after surgery. When a hematoma led to blood transfusion and/or surgery, it was defined as a postoperative bleeding. Information regarding malunion, nonunion and failure of the osteosynthesis material was extracted from the medical records and were diagnosed by the treating (orthopedic) trauma surgeon. The treating orthopedic trauma surgeon decided if revision surgery was necessary.
2.3
Outcomes
The LEFS questionnaire was sent to patients per (e)mail. When patients did not complete the questionnaire, either two reminders were sent via email or contact was made twice via telephone.
The Lower Extremity Functional Scale (LEFS) is a questionnaire validated to specifically monitor activity limitations of adults after lower extremity fractures. , Moreover, it is among the most frequently utilized measurement tools and is the only one that has attained a high-quality evidence rating for reliability. The questionnaire consists of 20 questions that assess the ability to perform everyday tasks, with a minimum score of 0 points and maximum score of 80 points. A higher LEFS means a better functional outcome of the lower extremity and a lower LEFS means a worse functional outcome. The population of this study will be distributed into four groups according to the median and inter quartile range of the LEFS, to compare differences in patients, fracture or treatment characteristics according to the LEFS.
2.4
Data analysis
A descriptive analysis was conducted on the patient and fracture characteristics, as well as questionnaire outcomes regarding LEFS. Absolute and relative frequencies were calculated for categorical variables, while median and interquartile range (IQR) were calculated for not normally distributed continuous variables. Pearson Chi-square test and Mann Whitney U test/independent sample median test were used, to assess significant differences between different groups of patients, for respectively nominal variables and (not normally distributed) continuous variables. For further analysis, variables with small subgroup sample sizes were combined. Univariate linear regression analysis was performed to investigate which variables are of significant influence on the LEFS. Significant variables in the univariate analyses as well as clinically relevant factors were put in a multivariate model. For variables with more than two subgroups (ie. ASA classification and Weber classification), the first group was selected as the reference category. All data was analysed using SPSS version 29.0.0.0, with a statistical significance set at p < 0,05.
3
Results
3.1
Participants
The dataset included 1804 patients, of which 841 (46.6 %) were surgically treated. These 841 patients showed a response rate of 65.6 % to fill out the complete questionnaire with a median of 2.3 years (IQR 1.5–3.1 years).
As shown in supplement A, all patients without a complete LEFS were excluded, resulting in 552 patients who were included in the analysis ( Fig. 1 ). Supplement B shows baseline characteristics of the included versus excluded patients. Included patients were more often female (60.9 % vs 48.8 %), had less comorbid diseases (ASA 1 and 2 86.6 % vs. 78.9 %) underwent less external fixation (1.5 % vs 5.2 %) or unimalleolar fixation (50.9 % vs 47.4 %) and more patients attended physiotherapy (72.1 % vs 65.1 %).
Participant flow.
Table 1 shows the patients’ demographics of the study population. The majority of patients were female (60.9 %), had more often an ASA 2 classification (50.4 %) and the median age was 51.0 years (OQR 35.0–63.0).
Table 1
Baseline characteristics of the study population, a total of 552 patients.
| A. Patient characteristics | |||
|---|---|---|---|
| n (%)/ Median (IQR) | |||
| Patient characteristics |
Sex
|
Male | 216 (39.1 %) |
| Female | 336 (60.9 %) | ||
| Age (years) | 51.0 (35.0– 63.0) | ||
| BMI (kg/m 2) | 26.54 (23.28– 30.83) | ||
|
ASA classification
|
1 | 200 (36.2 %) | |
| 2 | 278 (50.4 %) | ||
| 3 | 55 (10.0 %) | ||
| 4 | 5 (0.9 %) | ||
| Missing | 14 (2.5 %) | ||
| Abbreviations: IQR, Interquartile Range; BMI, Body Mass Index; ASA, American Society of Anesthesiologists; | |||
| B. Fracture characteristics | ||||
|---|---|---|---|---|
| n (%)/ Median (IQR) | ||||
| Fracture characteristics | Weber classification | Weber A | 42 (7.6 %) | |
| Weber B | 389 (70.5 %) | |||
| Weber C | 114 (20.7 %) | |||
| Missing | 7 (1.3 %) | |||
| Lauge Hansen classification | Supination exorotation | Type 1 | 0 (0.0 %) | |
| Type 2 | 65 (11.8 %) | |||
| Type 3 | 14 (2.5 %) | |||
| Type 4 | 288 (52.2 %) | |||
| Supination adduction | Type 1 | 6 (1.1 %) | ||
| Type 2 | 18 (3.3 %) | |||
| Pronation exorotation | Type 1 | 15 (2.7 %) | ||
| Type 2 | 3 (0.5 %) | |||
| Type 3 | 31 (5.6 %) | |||
| Type 4 | 83 (15.0 %) | |||
| Pronation adduction | Type 1 | 12 (2.2 %) | ||
| Type 2 | 1 (0.2 %) | |||
| Type 3 | 14 (2.5 %) | |||
| Missing | 2 (0.4 %) | |||
| Gustilo Classification | Closed | 528 (95.7 %) | ||
| 1 | 6 (1.1 %) | |||
| 2 | 7 (1.3 %) | |||
| 3 | 8 (1.4 %) | |||
| C. Treatment characteristics | |||
|---|---|---|---|
| n (%)/ Median (IQR) | |||
| Treatment characteristics | Type of fixation | Unimalleolar | 281 (50.9 %) |
| Bimalleolar | 226 (40.9 %) | ||
| Trimalleolar | 32 (5.8 %) | ||
| Other | 13 (2.4 %) | ||
| Missing | 5 (0.9 %) | ||
| Complication after surgery | None | 444 (88.4 %) | |
| Peripheral nerve injury | 5 (0.9 %) | ||
| Postoperative hemorrhage | 1 (0.2 %) | ||
| Malunion | 2 (0.4 %) | ||
| Nonunion | 7 (1.3 %) | ||
| Superficial infection | 60 (10.9 %) | ||
| Deep infection | 26 (4.7 %) | ||
| Failure of osteosynthesis material | 3 (0.5 %) | ||
|
Treatment with leg cast
|
Yes | 470 (85.1 %) | |
| No | 82 (14.9 %) | ||
| Duration of treatment with leg cast in weeks | 6.0 (min 1.0 to max 12.0) | ||
|
Physiotherapy postoperatively
|
Yes | 398 (72.1 %) | |
| No | 152 (27.5 %) | ||
| Missing | 2 (0.4 %) | ||
Most fractures were Weber B type fracture (70.5 %), Lauge Hansen classification SE type 4 (52.2 %) and were closed fractures (95.7 %). Treatment was mostly performed by unimalleolar fixation (50.9 %) and with a leg cast perioperatively (85.1 %) with a mean duration of 6 weeks (IQR 1.0–12.0). Thereby, most patients did not experience a complication (88.4 %) and the majority of patients attended physiotherapy (72.1 %).
3.2
LEFS
The median for the LEFS is 66.40 points (IQR 53.60–75.20 points). In Table 2 , a comparison is made between the patients with lower or a higher LEFS based on the median LEFS and the interquartile range (0–54, 54.01– 66.00, 66.01– 75.00, 75.01–80). Patients exhibiting the lowest LEFS scores were predominantly female (28.7 %), older (median 54.00 year), had a higher BMI (28.2 kg/m2), were more frequently classified as ASA 4 (100.0 %), sustained more often Weber C fractures (32.5 %), required trimalleolar fixation more often (37.5 %), experienced a higher incidence of complications (39.8 %), and more often attended physiotherapy (27.9 %) compared to patients with higher LEFS (LEFS 66.01–75.00 or 75.01–80). Details about the answers on the LEFS of the included patients are stated in supplement A. This shows that activities which are considered as extremely difficult are hopping (27.9 %), running on even (30.3 %) or uneven ground (37.3 %) and making sharp turns while running fast (34.6 %).
Table 2
Comparison of demographics of subgroups of LEFS score.
| 0–54.00 points (n = 139) | 54.01– 66.00 points (n = 132 | 66.01–75.00 points (n = 142) | 75.01–80 points (n = 139) | p- value | ||
| n (%)/ Median (IQR) | n (%)/ Median (IQR) | n (%)/ Median (IQR) | n (%)/ Median (IQR) | |||
|
Sex
|
Male | 43(19.9 %) | 39 (18.1 %) | 55 (25.5 %) | 79 (36.6 %) | < 0.001 * |
| Female | 96 (28.6 %%) | 93(27.7 %) | 87 (25.9 %) | 60 (17.9 %) | ||
| Age (years) | 54.00 (44.00–66.00) | 56.00 (42.00–65.00) | 51.00 (33.750–63.00) | 41.00 (25.00–56.00) | < 0.001 *** | |
| BMI (kg/m 2) | 28.19 (24.99–34.08) | 26.85 (23.00–30.81) | 26.00 (22.95–30.39) | 26.00 (23.25–28.84) | 0.010 *** | |
|
ASA classification
|
1 | 27 (13.5 %) | 38 (19.0 %) | 61 (30.5 %) | 74 (37.0 %) | < 0.001 * |
| 2 | 73 (26.3 %) | 78 (28.1 %) | 67 (24.1 %) | 60 (21.6 %) | ||
| 3 | 31 (56.4 %) | 11 (20.0 %) | 12 (21.8 %) | 1 (1.8 %) | ||
| 4 | 5 (100.0 %) | 0 (0.0 %) | 0 (0.0 %) | 0 (0.0 %) | ||
| Weber classification | Weber A | 11 (26.2 %) | 3 (7.1 %) | 8 (19.0 %) | 20 (47.6 %) | 0.001 * |
| Weber B | 87 (22.4 %) | 96 (24.7 %) | 106 (27.2 %) | 100 (25.7 %) | ||
| Weber C | 37 (32.5 %) | 31 (27.2 %) | 27 (23.7 %) | 19 (16.7 %) | ||
| Type of fixation | Unimalleolar | 57 (20.3 %) | 54 (19.2 %) | 72 (25.6 %) | 98 (34.9 %) | < 0.001 * |
| Bimalleolar | 64 (28.3 %) | 67 (29.6 %) | 58 (25.7 %) | 37 (16.4 %) | ||
| Trimalleolar | 12 (37.5 %) | 9 (28.1 %) | 9 (28.1 %) | 2 (6.3 %) | ||
| Other | 2 (25.0 %) | 2 (25.0 %) | 2 (25.0 %) | 2 (25.0 %) | ||
| Complications | No | 96 (21.6 %) | 106(23.9 %) | 126 (28.4 %) | 116 (26.1 %) | < 0.001 * |
| Yes | 43 (39.8 %) | 26 (24.1 %) | 16 (14.8 %) | 23 (21.3 %) | ||
|
Treatment with leg cast
|
No | 14 (17.1 %) | 11 (13.4 %) | 29 (35.4 %) | 28 (34.1 %) | 0.004 * |
| Yes | 125 (26.6 %) | 121(25.7 %) | 113 (24.0 %) | 111 (23.6 %) | ||
|
Physiotherapy postoperatively
|
No | 28 (18.4 %) | 29 (19.1 %) | 41 (27.0 %) | 54 (35.5 %) | 0.002 * |
| Yes | 111 (27.9 %) | 102 (25.6 %) | 101 (25.4 %) | 84 (21.1 %) | ||
| Follow-up period (days) | 859.00 (517.00–1158.00) | 861.00 (537.25–1153.25) | 815.50 (558.00–1074.50) | 857.00 (613.00–1158) | 0.666*** | |
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