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Fifty-two patients with unstable fractures of distal clavicle treated by open reduction and internal fixation with hook plates or tension band wires were retrospectively reviewed. The 52 patients were divided into two groups based on the method of treatment. The hook plate (HP) group included 32 patients and the tension band wire (TBW) group included 20 patients. Both groups were similar in respect to injury mechanisms, compounding medical conditions, and shoulder score (p>0.1). However, hook plating had a significantly lower rate of complication (p=0.01) and symptomatic hardware (p=0.001). In addition, hook plating better facilitated the return to work and athletic activity (p=0.004 and p=0.003, respectively). In conclusion, if surgery of distal clavicular fractures is indicated, internal fixation with a hook plate has more advantages than with tension band wires.
52 patients présentant une fracture instable de la clavicule ont été traités par réduction sanglante et fixation interne par plaques crochet. Les 52 patients ont été revus et ont été divisés en deux groupes en fonction de la méthode de traitement. L’ostéosynthèse par plaques crochet HP groupe 1 incluait 32 patients et le haubannage TBW 20 patients. Les deux groupes sont identiques en ce qui concerne le mécanisme des traumatismes, les problèmes médicaux, les scores épaule (p>0,1). Cependant le traitement par crochet-plaque permet une diminution significative des complications (p=0,01) notamment matérielles (p=0,001). Par ailleurs cette ostéosynthèse par crochet-plaque permet une reprise plus rapide du travail et des activités sportives (p=0,004, 0,003 respectivement). En conclusion, si il existe une indication chirurgicale dans les fractures distales de la clavicule, il est indiqué de réaliser l’ostéosynthèse par crochet-plaque. Cette ostéosynthèse présente beaucoup plus d’avantages que l’ostéosynthèse par hauban.
Distal clavicle fracture with rupture of the coracoclavicular ligament (Neer type II) is unstable and is usually accepted as an indication for surgical treatment [1, 4, 8, 10–13]. One of the popular surgical methods is trans-articular or extra-articular tension band wire fixation, but that involves considerable risks for complications, especially loss of reduction, pin migration, and skin ulceration due to pin irritation [5, 7–9]. If the distal fragment is small or comminuted, it is difficult to achieve stable fixation and early mobilisation. A hook plate with an extension under the acromion has been developed to provide more rigid fixation. However, the main concern is subacromial impingement or rotator cuff injury .
To date, there have been few reports comparing the results of hook plate and tension band wire fixation for distal clavicular fractures. The purpose of this study was to retrospectively review the clinical outcomes between the two techniques. Also, the functional recovery and the complications were analysed in detail.
Between 2000 and 2007, 66 adults who had unstable fractures of the distal clavicle were surgically treated at an orthopaedic institution. Inclusion criteria for this study were (a) Neer type II fractures, (b) acute and unilateral fractures, (c) internal fixation with either an AO hook plate (HP) or tension band wire (TBW), and (d) normal shoulder function before injury. There were 57 patients who met the inclusion criteria. However, five patients could not be followed-up due to relocation, and they were excluded. Therefore, 52 patients with an average age of 40.5 years (range 18–70) were followed-up more than 12 months after discharge from the hospital and were included in this study. The average follow-up was 26.4 months (range 12–64). There were seven surgeons involved in our study. The 52 patients were divided into two groups, based on the method of treatment. The HP group (Fig. 1) included 32 patients with an average age of 43.4 years. Twenty-five patients (78.1%) suffered from vehicular trauma. The mean follow-up was 24.3 months. The TBW group included 20 patients with an average age of 35.9 years. In the TBW group, 16 patients (80%) suffered from vehicular trauma. The mean follow-up was 29.8 months. The injury mechanisms and demographics related to the groups are shown in Table 1.
In the HP group, the operative procedure has been described in previous studies [5, 6, 16]. A tunnel was made in the subacromial space behind the acromio-clavicular joint and the hook was inserted into this tunnel. If necessary, the plate was bent to fit the shape of the clavicle. Plate bending was necessary for 15 patients. The plate was fixed using dynamic compression, if possible. Mobilisation was started as soon as possible and full range of motion was usually achieved after three to four weeks. Heavy manual work was not allowed until solid union of the fracture was noted. In the TBW group, the fixation method was transarticular through the acromioclavicular joint in 14 cases and extraarticular in six. An additional cerclage wire tension band was used in all 20 patients to obtain more stable fixation. The operated shoulder was protected with a triangular sling for four weeks. Gentle mobilisation was allowed after the pain resolved. A full range of motion was restricted in transarticular cases due to impingement of the pin until the implant was removed.
After osteosynthesis, plain radiographs were taken once every four weeks for all patients. These roentgenograms were examined for evidence of fracture healing and implant position. Radiographic healing was interpreted by the attending surgeon at each follow-up and was verified by the all authors of this study. Radiographic healing was defined as evidence of bridging callus across the fracture sites or the obliteration of the fracture lines.
At the last follow-up, the results were evaluated according to the shoulder scoring system of Constant and Murley . In this system, both subjective and objective clinical data are included, with a maximum score of 100 points. Pain (15 points), activities of daily living (20 points), range of motion of the shoulders (40 points), and muscle power (25 points) were evaluated. The Student’s t-test, chi-square test with Yates’ correction, and Fisher’s exact test were used to compare the two groups. The statistic software SPSS 10.0 (SPSS, Inc., Chicago, IL) was used to analyse the data; p values below 0.05 were considered significant.
Both groups were similar for age, gender, and confounding medical condition (p>0.1) (Table 1). In the HP group, all the fractures (100%) healed in six months. In the TBW group, all but one fracture (95%) healed in six months. There was no difference in the union rate (p=0.39). In the HP group, the mean score for the affected shoulder using the scoring system of Constant and Murley was 90 points (84–100), and the mean score for the contralateral shoulder was 94 points (89–100). In the TBW group, the mean score for the affected shoulder was 88 points (75–100), and the contralateral shoulder was 93 points (85–100). In the HP or TBW groups, the mean scores between the involved shoulder and the contralateral shoulder were not different (p=0.25 and p=0.18, respectively). In addition, both groups had similar mean score of the involved shoulder (p=0.65) (Table 2).
The HP group experienced fewer complications than the TBW group (p=0.01, Fisher’s exact test). The HP group had one complication (3.1%) related to screw loosening with partial loss of reduction. The TBW group had six instances of complications (30%) consisting of three partial losses of reduction, one complete loss of reduction with nonunion, and two superficial infections. In the HP group, an elderly female patient (70 years old) had loosening of the screws four weeks after surgery, which might have been due to her poor bone quality. In addition, the plate was not bent to an adequate shape. The final shoulder score was 84 points. In the TBW group, three patients had partial loss of reduction and one of them had a broken wire (Fig. 2). One case had complete loss of reduction with symptomatic nonunion that required a secondary surgery with bone graft. The final shoulder score was 75 points. Superficial infection due to pin migration with pin end irritation or penetration developed in two cases. Both the superficial infections were diagnosed clinically at the first follow-up visit, which was seven to ten days after surgery. A one-week regimen of oral antibiotics resolved the infections.
In the HP group, eleven patients (34.4%) had the bulky palpable plate, especially in slim females. Removal of the hook plate is recommended if solid union has been achieved. Therefore, the plates were removed in 32 patients (100%) at an average of 4.8 months. In the TBW group, 17 out of 20 patients (85%) had symptomatic hardware. Nineteen out of 20 patients (95%) asked to have the hardware removed. The HP group experienced fewer hardware symptoms (p=0.001). However, elective hardware removal did not significantly differ between the two groups (p=0.39).
In the HP group, all but two cases (93.75%) returned to their previous work three months postoperatively. Twenty-six patients (81.25%) could do the same athletic activities six months after surgery. In the TBW group, 12 patients (60%) returned to their previous work three months postoperatively. Eight patients (40%) could do the same athletic activities six months after surgery. There was significant difference in returning to work and athletic activity between the HP and TBW groups (p=0.004 and p=0.003, respectively) (Table 2).
Several studies have recommended open reduction and internal fixation in Neer type II fractures of the distal clavicle because of their tendency to slow healing [8, 13, 15–17]. There are many implants available to treat these cases. Although coracoclavicular screw fixation is a good method that can achieve good results , it is difficult to perform and may result in failure if the shoulder is mobilised early. One of the popular methods is trans-articular or extra-articular K-wire fixation. However, Kona et al.  reported 47% complication rate and 32% nonunion rate using trans-acromial K-wire fixation. The unacceptable clinical results made them abandon this method. Conversely, Neer  and Eskola et al.  had good clinical results with few complications. In our study, although the TBW group had good functional results with high union rate (95%), frequent complications (30%) were noted. Several studies reported that the common complication of K-wire fixation was loss of reduction [5, 7, 8]. In our series, K-wire fixation with an additional cerclage wire tension band was used to achieve more stability. However, four cases had loss of reduction related to pin migration or broken wire. We think that the K-wire without threads has an essential risk of pin migration. In addition, during mobilisation of the shoulder, rotation of the clavicle causes migration of the K-wires. This strong force results in, not only pin migration, but also broken cerclage wires.
The distal clavicle fracture treated with hook plate fixation is a relatively new method. This creative design with a hook plate gives a more stable fixation. In the literature, most papers reported good results with few complications [5, 6, 10, 11, 16]. Our results were compatible with theirs and only one complication developed in our series. However, a few studies mentioned that distal clavicular fracture treated with a hook plate might develop subacromial impingement or rotator cuff injury if the hook is placed in an inadequate position . In our series, we found no evidence of subacromial impingement or rotator cuff injury, although it is inserted into the subacromial space.
In our study, the functional shoulder score showed no difference between the HP and TBW groups. However, the HP group had greater ability to return to their previous work in three months after surgery compared to the TBW group. We determined that the hook plate gave very stable fixation with early shoulder range of motion. The patients treated with this method had a grater ability to return to work and previous athletic activities in a shorter time.
Although surgical treatment is generally accepted as the treatment of choice in unstable distal clavicle fractures, its natural course if left untreated is not well known. Surgery is usually recommended on the basis of retrospective analysis of a small number of patients, suggesting that failure to operate will lead to nonunion in up to 30% of cases [3, 12]. Nordqvist et al.  reported on 110 fractures of the distal clavicle, of which 23 were unstable fractures treated with non-operation. Nonunion occurred in five of the cases. However, the result was regarded as good in three and fair in two. They concluded that surgical treatment is unnecessary. In our study, 52 unstable clavicular fractures treated with surgery developed only one nonunion (1.9%). We thought that surgical treatment of unstable fractures of the distal clavicle might decrease the nonunion rate. It remains uncertain whether unstable fractures of the distal clavicle treated surgically can achieve better clinical results. To date, no prospective randomised studies have compared surgical and nonsurgical treatment of this fracture.
This study had various limitations: (a) it was a retrospective study and not randomised, which could produce a selection bias; (b) this study was performed in a teaching institution where the resident was the operating surgeon and the surgeons’ level of experience could influence the outcomes; and (c) the study was not a large series and when we calculated the power of this study, most were only 80%–90%. If the null hypothesis (no difference between the groups) was accepted in our study, the false-negative rate was up to 10–20%.
In conclusion, both hook plating and tension band wiring for treatment of unstable fractures of the distal clavicle could achieve good results. However, internal fixation with a hook plate had more advantages and fewer complications than the tension band wire.