1. Introduction
The strategy for treating midshaft clavicle fractures has been discussed for the past 2 decades. Conventionally, nonoperative treatment has been the mainstream approach. The report by the Canadian Orthopaedic Trauma Society demonstrated that primary plate fixation for displaced midshaft clavicle fractures resulted in improved functional outcome and a lower rate of malunion and nonunion compared with those with nonoperative treatment.1 2
Regarding plate fixation for midshaft clavicle fractures, the superior plating technique has been predominant for a long time.3,4 5–7 8–10 11,12 13
Although superior plating has been used in our institution for several years, we have drastically shifted our standard surgical procedure from superior to anteroinferior plating since April 2018, anticipating longer bicortical screw paths and theoretically lower risks of neurovascular damage by drilling.14,15
2. Materials and Methods
2.1. Study Design
This retrospective cohort study was conducted after obtaining approval from the institutional review board. Data were collected from a longitudinal database of midshaft clavicle fractures in our institution. The surgery was performed for patients with Robinson type 2A2, 2B1, and 2B2 fractures. For patients with Robinson type 2A2 fractures, the surgery was performed when the fracture was complete, when the angular deformity was 20 degrees or more, or when patients preferred surgery to alternative options, including conservative treatment. Eighty-seven patients were diagnosed with midshaft clavicle fractures and underwent open reduction and plate fixation between April 2016 and March 2020. We included an aggregate of 71 patients 16 years or older and followed up at least 6 months after plate fixation.
The 71 patients were divided into 2 groups: 39 and 32 in group “superior plate” (Group SP) and in group “anteroinferior plate” (Group AIP), respectively (Fig. 1 ). The rate of symptomatic implant removal was investigated as the primary outcome in both groups. After the bone union was confirmed on x-ray, the implant was removed according to the same protocol in Groups SP and AIP. It was conducted for the patients who complained of symptoms, such as discomfort, pain, and prominence, and agreed to the removal. We did not conduct the removal for patients without any symptoms, except for those who strongly requested it. These exceptional cases were excluded from the symptomatic implant removal reported here. Postoperative follow-up was handled by the orthopaedic surgeon responsible for the primary surgery.
Figure 1.: Selection of patients.
2.2. Surgical Procedures
All cases during the study period were supervised by the same chief surgeon (H.S), and 11 orthopaedic surgeons participated in the surgeries as assistants. Assistant surgeons who performed surgeries between April 2016 and March 2018 used SP, while other assistants who performed surgeries between April 2018 and March 2020 used AIP.
2.3. Superior Plate Fixation
The patient was placed in a modified beach chair position. The skin incision was centered over the fracture site according to the bone axis. We attempted to preserve the supraclavicular nerve for all cases to reduce the postoperative risk of paresthesia in front of the clavicles (Fig. 2 ).16
Figure 2.: Superior plating. The image illustrates the superior plate below the preserved supraclavicular nerves (white arrowheads).
2.4. Anteroinferior Plate Fixation
Patients undergoing AIP fixation were placed in a modified beach chair position. As performed in the superior plate positioning, the skin incision was centered over the fracture and made parallel to the clavicle line. In subcutaneous dissection, an attempt was made to preserve the supraclavicular nerve (Fig. 3 ). Around the proximal side of the clavicle, the pectoralis major muscle was detached. On the other hand, the deltoid muscle was detached at the distal side of the clavicle to secure space for attaching the plate. After minimal dissection of the clavicle periosteum to expose the fracture, anatomic reduction was performed using lag screws in applicable cases, and a variable angle-locking compression plate (VA-LCP) anterior clavicular plate (DePuy Synthes, West Chester, PA) was used as the neutralization plate. For comminuted fractures, locking plates were used as bridging plates. The anteromedial to superolateral VA-LCP was not used in our institution.
Figure 3.: Anteroinferior plating. The image shows the anteroinferior plate positioned below the preserved supraclavicular nerves (white arrowheads).
3. Outcome Assessment
The electronic medical records were reviewed for baseline patient characteristics, complications, and implant removal during follow-up. The detailed reasons for implant removal were examined, whether the patient wanted to remove the plate for specific reasons including pain and prominence or patients' request. We also examined the radiographs taken at 1, 3, and 6 months after surgery to ensure that the plate was correctly positioned. Bone union was defined when the fracture line disappeared. The bone union was evaluated independently by 2 orthopaedic surgeons (A.A. and H.S.), and the average time for the bone union was calculated and shown as the days from the primary surgery. The symptomatic implant removal rates and the bone union in each group were set as the primary and secondary outcome parameters, respectively.
3.1. Statistical Analysis
Statistical analyses were conducted using R (manova; R ver. 4.0.2). Differences between groups were compared using the Mann–Whitney U test for continuous data and the Fisher exact test for categorical data. Based on the previous report17 2 is defined “preobese.” The difference was considered statistically significant when P < 0.05.
4. Results
4.1. Baseline Characteristics
Table 1 presents the demographic data of the patients. There was no significant difference between Groups SP and AIP for age, sex, BMI, time from injury to surgery, time to evaluation, fracture side, the dominant hand, Robinson classification, mechanism of injury, multiple injuries, and American Society of Anesthesiologists physical status.
TABLE 1 -
Baseline Characteristics of Patients
Group SP (n = 39)
Group AIP (n = 32)
P
Mean age (yr)
47.4 ± 14.9
47.8 ± 17.1
0.922*
Sex, n (%)
Female
7 (17.9)
7 (21.9)
0.768†
Male
32 (82.1)
25 (78.1)
BMI (kg/m2 )
23.5 ± 3.9
24.7 ± 3.2
0.194*
Mean time from injury to surgery (days)
6.6 ± 3.3
9.2 ± 8.5
0.056*
Mean time from primary surgery to implant removal (days)
310 ± 70.9
313 ± 64.0
0.773*
Mean follow-up (days)
327 ± 97.9
389 ± 160
0.600*
Fracture side, n (%)
Right
20 (51.3)
17 (53.1)
1.00†
Left
19 (48.7)
15 (46.9)
Dominant hand, n (%)
Right
38 (97.4)
32 (100)
1.00†
Left
1 (2.6)
0 (0)
Robinson classification, n (%)
2A2
2 (5.1)
2 (6.3)
1.00†
2B1
15 (38.5)
16 (50.0)
0.348†
2B2
22 (56.4)
14 (43.8)
0.344†
Mechanism of injury, n (%)
Car accident
3 (7.7)
1 (3.1)
1.00†
Motorcycle accident
14 (35.9)
14 (43.8)
0.626†
Bicycle accident
4 (10.3)
69 (18.8)
1.00†
Fall from standing height
11 (28.2)
8 (25.0)
1.00†
Sports injury
7 (17.9)
3 (9.4)
0.495†
Multiple injury, n (%)
Yes
13 (33.3)
10 (31.3)
1.00†
No
26 (66.7)
22 (68.8)
American Society of Anesthesiologists physical status, n (%)
1
20 (51.3)
18 (56.3)
0.812†
2
19 (48.7)
12 (37.5)
0.471†
3
0 (0)
2 (6.3)
0.200†
Data are shown as mean ± SD or numbers. P < 0.05 indicates statistical significance.
* Mann–Whitney U test.
† Fisher exact test.
4.2. Symptomatic Implant Removal Rates
As presented in Table 2 , the rate of symptomatic implant removal was significantly lower in patients in Group AIP than in patients in Group SP (P = 0.033). A similar number of patients in the 2 groups requested removal despite no implant-related symptoms (P = 1.00).
TABLE 2 -
Implant Removal Rates
Group SP (n = 39)
Group AIP (n = 32)
P
Symptomatic, n (%)
21 (53.8)
9 (28.1)
0.033
Patients' request, n (%)
5 (12.8)
4 (12.5)
1.00
Differences between groups were compared using the Fisher exact test. P < 0.05 indicates statistical significance.
4.3. Bone Union
Table 3 presents every patient in both Groups SP and AIP that achieved bone union. The mean time to bone union was not significantly different between the 2 groups (P = 0.694).
TABLE 3 -
Bone Union and Intraoperative Data
Group SP (n = 39)
Group AIP (n = 32)
P
Bone union, n (%)
Yes
39 (100)
32 (100)
1.00*
No
0 (0)
0 (0)
Mean time to bone union (days)
89.2 ± 21.7
95.2 ± 30.8
0.694†
Data are shown as mean ± SD or numbers. P < 0.05 indicates statistical significance.
* Fisher exact test.
† Mann–Whitney U test.
4.4. Intraoperative Factors
Table 4 presents a comparison of the intraoperative factors between Groups SP and AIP. The duration of the operation (P = 0.083) and anesthesia (P = 0.201) was not different between the 2 groups.
TABLE 4 -
Intraoperative Data
Group SP (n = 39)
Group AIP (n = 32)
P
Operation time (min)
96 ± 0.016
103 ± 0.011
0.083
Anesthesia time (min)
141 ± 0.017
147 ± 0.016
0.201
Differences between groups were compared using the Mann–Whitney U test. P < 0.05 indicates statistical significance.
4.5. Independent Factors for Decreasing the Symptomatic Implant Removal Rates
As presented in Table 5 , the multivariate analyses revealed that anteroinferior plating (P = 0.037), 45 years or older (P = 0.029), and BMI ≥25 kg/m2 (P = 0.034) were independently associated with significantly low implant removal rates.
TABLE 5 -
Risk Factors for Symptomatic Implant Removal
Multivariate Analysis
Odds Ratio [95% Confidence Interval]
P
Plate
Superior plate
1 (base)
0.037
Anteroinferior plate
0.323 [0.111, 0.935]
Age
≥45 years
0.312 [0.110, 0.888]
0.029
<45 years
1 (base)
Sex
Male
2.960 [0.693, 12.60]
0.143
Female
1 (base)
BMI
≥25
0.117 [0.016, 0.846]
0.034
<25
1 (base)
The factors were evaluated using multivariate logistic regression. P < 0.05 indicates statistical significance.
5. Discussion
Baltes et al reported that anteroinferior plating resulted in a low implant removal rate. However, neither control groups nor statistical analyses were described in their report.18 12 13
In the multivariate analyses, anteroinferior plating, 45 years or older, and BMI ≥25 kg/m2 were found to be independent factors for decreasing the implant removal rates after plate fixation for midshaft clavicle fractures. Among these independent factors, age and BMI are unalterable patients' background characteristics from a medical viewpoint. However, the plating technique is the only factor that can be altered by medical institutions. In other words, we could decrease the rate of postoperative implant-related irritation, including pain and prominence by means of plating technique. Furthermore, no significant difference of bone union between Groups SP and AIP was noted. These are substantial reasons for recommending anteroinferior plating for midshaft clavicle fractures.
This study also analyzed the intraoperative factors in addition to patients' characteristics and postoperative implant removal rates. Both operation and anesthesia time were comparable between Groups SP and AIP, although anteroinferior plating requires additional steps of surgical technique in which we detach the major pectoral and the deltoid muscle from the clavicle, while superior plating involves separation of only the soft tissue above the clavicle.
In our analyses, the symptomatic implant removal rates were 53.8% for superior plating and 28.1% for anteroinferior plating. These rates were much higher than those reported in previous studies, which ranged from 0% to 20.3% for superior plating1,19–27 9,28–31
This study has several limitations to be addressed. First, it was a retrospective cohort study conducted with a relatively small number of patients in a single center. Second, the mean follow-up period was relatively short. However, during the follow-up period in this study, we identified bone unions in all cases in both groups, confirming a request for symptomatic plate removal. In cases where patients requested implant removal at other institutions, we provided them with detailed information about their implants. In Japan, when removing the implants operated in other institutions, we always contact the previous doctor to confirm the details of the surgery and implant type. Therefore, it is unlikely that the patients treated in our institute undergo plate removal without our awareness. Third, there was ambiguity in the decision for implant removal in this study. Although we conducted implant removal for only patients who complained of symptoms, it would be undeniable that orthopaedic surgeons have contributed some subjective factors to the decision of the implant removal. Moreover, patient-based evaluation was not reviewed. Further studies with larger numbers of patients and a longer follow-up period are required. Although this study was not randomized, we standardized the plating technique by the period but not by the characteristics of the patients or clavicle fractures, which allowed us to discuss the clinical outcomes mostly from the viewpoint of different plating positions.
6. Conclusions
Anteroinferior plating, ≥45 years or older, and BMI ≥25 kg/m2 were the independent factors for decreasing the symptomatic implant removal rates after plate fixation for midshaft clavicle fractures in our multivariate analyses. Plating technique is the only factor that can be altered by medical institutions. Therefore, we recommend anteroinferior plating for displaced midshaft clavicle fractures to reduce a second surgery such as symptomatic implant removal.
Acknowledgments
The authors would like to thank Enago (www.enago.jp
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