CORACOCLAVICULAR RECONSTRUCTION USINg TENDINOUS gRAfT fOR CHRONIC ACROMIOCLAVICULAR jOINT DISLOCATION

Study conducted at LIM 41 – Musculoskeletal Medical Investigation Laboratory of the Department of Orthopedics and Traumatology of the Faculty of Medicine of Universidade de São Paulo. Mailing address: Rua Dr. Ovídio Pires de Campos, 333 3° andarCerqueira Cesar São Paulo SP Brazil Cep: 05403-010 E-mail: jhassuncao@uol.com.br CORACOCLAVICULAR RECONSTRUCTION USINg TENDINOUS gRAfT fOR CHRONIC ACROMIOCLAVICULAR jOINT DISLOCATION


IntroductIon
Symptomatic chronic acromioclavicular (AC) joint dislocation is seldom discussed in literature and consequently there is no consensus regarding its treatment.Although one of the recommended treatments is distal exeresis of the clavicle 1,2 for the treatment of local arthrosis, the presence of dislocated and unstable clavicle can, with time, produce important disorders in dynamic stabilization, in muscle strength of the shoulder, and in the subacromial sliding mechanism.In type I and II lesions of Rockwood et al. 1 , where the clavicle is stable, exeresis of the distal extremity of the clavicle can be used successfully.However, in type III, IV and V chronic AC dislocations, in addition to this procedure, it is also necessary to perform some kind of clavicle stabilization aiming to reestablish the anatomical rela-tionship of the acromioclavicular joint and if possible to replace the torn coracoclavicular ligaments.The clavicle stabilization method most frequently employed nowadays is coracoclavicular stabilization through subcoracoid ligatures with a wide variety of synthesis materials, including highly resistant non-absorbable threads and Dacron or polyester tape. 3,4Although they can be resistant and keep the clavicle stable, there is consensus in literature regarding the need to perform reconstruction of the coracoclavicular ligaments in order to definitively reconstitute the local anatomy.6][7][8] However, biomechanical studies for this reconstruction have recently shown greater mechanical resistance with other types of graft. 9,10ne of the first uses for this purpose was the tendon of the tensor fasciae latae. 11][14] The aim of this study is to evaluate the radiographic and functional results of patients that have undergone treatment for chronic AC dislocations with reconstruction of the coracoclavicular ligaments with semitendinosus graft.

cAsuIstrY And MEtHod
Fifteen patients with symptomatic chronic acromioclavicular joint dislocation were selected for this study.The inclusion criteria were: Rockwood degree III, IV and V acromioclavicular dislocation lasting for more than three weeks and symptomatic (pain, loss of muscle strength of the scapular girdle); patients between 18 and 60 years of age.The exclusion criteria were: patients already submitted to other surgical procedures not related to the acromioclavicular dislocation in the same shoulder, other associated lesions in the same upper limb, failure to agree to take part in the study and inadequate follow-up in the postoperative period.Of the group of fifteen patients, two were excluded due to inadequate follow-up in the postoperative period, totaling thirteen patients included in the study.The patients were submitted to surgical treatment between April 2007 and June 2008, with mean follow-up time of 16 months (12-26 months).Twelve patients were male and one female and the mean age was 33.3 years (20-55 years).Eight had their right side affected and seven the left, while nine patients had the dominant side involved.Nine suffered a fall in road accidents (motorcycle, bicycle and pedestrians run over by vehicle), two experienced simple falls to the ground and two fell from heights.The mean interval between the trauma and the surgical procedure was nine months (2-38).Using Rockwood's classification, 10 patients had type V dislocation and three had type III.(Table 1) Eight patients (61%) did not have any previous surgical treatment for acromioclavicular dislocation in the acute phase.Five underwent coracoclavicular reduction and stabilization with the use of two anchors, with three patients via the arthroscopic and two via the open approach.(Table 1) Seven patients received grafts from a tissue bank while the graft was autologous in six.The graft used was the semitendinosus tendon.All the patients were submitted to radiographic evaluation in the preoperative and immediate postoperative periods, and at 15 and 45 days, three and six months and one year after surgery.The radiographies taken were: 1) anteroposterior (AP) view; 2) axillary view to evaluate the congruence of the acromioclavicular joint in the anteroposterior direction; 3) AP view at 15° of cephalic inclination, with both shoulders on the same film to measure the coracoclavicular distance.The measurement of the dislocated clavicle deviation was expressed in percentage according to the following calculation: ((Coracoclavicular distance from the dislocated side -Coracoclavicular distance from the normal side) x 100) / Coracoclavicular distance from the normal side).(Figure 1) All the patients underwent clinical evaluation in the preoperative period and postoperatively at six months and one year by a physiotherapist not participating in the study, using the Constant and University of California Los Angeles' (UCLA) evaluation methods.The pre-and postoperative quantitative data were evaluated statistically by the Wilcoxon method.

surGIcAL tEcHnIQuE
All the patients were submitted to general anesthesia and placed in beach chair position.A lengthwise incision was made in the shoulder, starting over the clavicle, 35mm medial to the acromioclavicular joint, and reaching up to the apex of the coracoid process; the deltoid and trapezius muscles were detached subperiosteal from the clavicle and their distal extremity (10mm of extension on average) was submitted to exeresis.The tendinous graft used was semitendinosus originating from a tissue bank or taken from the actual patient's contralateral limb.(Figure 2 and 3) The previously prepared   graft was then passed, together with four non-absorbable sutures (Ethibond® 5) under the coracoid process.Five tunnels were made in the distal clavicle: one of the tendinous graft stumps was passed through the central tunnel and the other over the clavicle and through the peripheral tunnels (two anterior and two posterior) to the sutures.(Figure 4) The clavicle was reduced and the sutures tied, reestablishing the anatomical relationship of the acromioclavicular joint or even with slight hyper-reduction.Afterwards the graft stumps were sutured with tendon-tendon stitches.(Figure 5) The deltoid and trapezius muscles were reinserted in the clavicle and the subcutaneous tissue and skin were sutured.(Figure 6) The patients remained immobilized with a splint for six weeks and started the physiotherapy treatment in the third week, with passive elevation only allowed up to 90°.Starting from the sixth week, the immobilization device was removed and the patients were cleared for active and active assisted movement.Exercises against resistance were only commenced after the twelfth week.

rEsuLts
In this group of 13 patients, with minimum follow-up of one year, the Constant score ranged from 60.9 (26-88) in the preoperative evaluation to 87 (60-98) in the last evaluation in the postoperative period.The UCLA score went from 16.8 (11-27) in the preoperative period to 33 (29-35) in the postoperative evaluation.The functional improvement quantified by these scores was statistically significant (p=0.001).(Table 2) In the physical examination, held one year after surgery, only one patient presented clavicle instability in the anteroposterior and craniocaudal directions.
In the radiographs taken in the preoperative period, the measurement of the coracoclavicular distance from the affected side was, on average, 129% greater than the distance from the normal side.In the radiographs after one year of follow-up it was 1.84%, a statistically significant improvement (p=0.001).
In the immediate postoperative radiographs of two patients we found an anatomical reduction of the acromioclavicular joint, the distance from the coracoclavicular space of the affected shoulder was equal to the space of the contralateral shoulder and in 11 patients we found hyper-reduction in the craniocraudal    direction with mean value of 50% (10-200%).In the axillary view, the reduction was anatomical in the anteroposterior direction in all patients.
In the radiographic control one year after surgery, we found 12 patients with anatomical reduction both in the craniocaudal and in the anteroposterior direction.Only in patient number 12 was the measurement of the coracoclavicular space on the operated side 45% greater than the normal side, while it was 250% greater in the preoperative period.We had two complications, one patient with superficial infection in the surgical wound, which was resolved with surgical flushing and the use of antibiotic therapy (patient number 12).The other patient did not use the splint appropriately in the postoperative period and lost the reduction.This patient was submitted to further surgical treatment using the same technique with optimal results.All patients were satisfied with the surgical procedure.

dIscussIon
Surgical treatment is indicated in chronic dislocations, when symptomatic.In type I and II lesions, where the clavicle is stable, resection of the distal portion of the clavicle alone is sufficient for us to eliminate patients' painful symptoms.In type III, IV and V lesions, besides acromioclavicular joint reduction it is imperative to reconstruct the coracoclavicular ligaments.][7] Biomechanical studies have shown that the isolated transfer of the coracoclavicular ligament presents less mechanical resistance, both in the superior and posterior directions, than in comparison to native coracoclavicular ligaments. 9,16Some studies have shown that the reconstruction of these ligaments with tendinous grafts has greater mechanical resistance, comparable to that of the coracoclavicular ligaments and superior to the Weaver-Dunn technique associated or not with coracoclavicular fixation. 9,10,17,18iming to clinically verify the superiority of the reconstruction of coracoclavicular ligaments with tendinous grafts, several authors conducted studies with this technique in the treatment of chronic AC dislocation.In 2001, Jones et al. 11 described a case in which they obtained an optimal result.Later on other studies, with a larger number of cases, 12,19 showed excellent clinical and radiographic results similar to that found in our study.More recently, Tauber et al. 20 carried out a prospective study comparing the Weaver-Dunn technique with tendon reconstruction and obtained superior clinical and radiographic results when using the last technique.Like Nicholas et al. 19 , we performed the reconstruction fixing the graft through a single bone tunnel in the clavicle.However, other authors 12,20,21 preferred to perform this fixation through two tunnels with the objective of reproducing the anatomical orientation of the conoid and trapezoid ligaments.It should be noted that the creation of two tunnels in the clavicle increases the risk of fracture particularly in narrower clavicles or when it is necessary to create larger tunnels for the passage of wider grafts.In our cases we did not have fracture or osteolysis of the clavicle.
We believe, according to some authors, 12,19,20 that ligament reconstruction should be protected with coracoclavicular fixation, which in this study was performed with subcoracoid ligature (non-absorbable threads -Erthibond® 5).Furthermore, as a form of protection, to avoid lengthening of the graft during the healing phase, active flexion-abduction of the operated limb was not allowed for six weeks.We had a case of reduction loss in the first months of the postoperative period, as the patient did not respect the immobilization period.We observed during reoperation that the Ethibond ® threads had snapped and the graft was integrated to the clavicle, but lengthened.We recommend hyper-reduction of the acromioclavicular joint in the craniocaudal direction, since as noticed in other studies, 17,20 during the revascularization phase, the graft, even though protected with a form of acromioclavicular fixation, undergoes lengthening.As verified in our study with 11 patients in the immediate postoperative radiograph we encountered hyper-reduction in the craniocaudal direction, averaging 50% and after one year they all presented anatomical reduction, indicating graft lengthening.This does not apply to the anteroposterior direction, where anatomical reduction should be performed in the intraoperative period.Our functional and radiographic results were highly satisfactory with this kind of reconstruction in accordance with studies in literature. 12,19,20Our personal experience with ligament reconstruction in chronic AC dislocations using the Weaver--Dunn technique 8 is not good with high rates of reduction loss (67% -data not published).Coracoclavicular reconstruction with tendinous graft appears to us to be an appealing and viable technique, and is currently the treatment of choice for this pathology in our service.

concLusIon
The functional and radiographic result was very satisfactory in patients submitted to reconstruction of chronic acromioclavicular dislocations, with a low rate of recurrence.

Figure 1 .
Figure 1.Anteroposterior radiograph at 15 degrees of cephalic inclination, with measurement of the coracoclavicular distance from both sides.The clavicle on the affected side is 77% further from the coracoid process in relation to the normal side.

Figure 3 .
Figure 3. Removal of the graft with the assistance of a tendon striper.

Figure 6 .
Figure 6.Reinsertion of the deltoid and trapezius muscles in the distal clavicle.

Figure 5 .
Figure 5. Joint reduction, having tied the Ethibond sutures and performed tendon-tendon stitches in the graft.

Figure 4 .
Figure 4. Passage of the graft through the central tunnel and Ethibond sutures through the peripheral tunnels.

table 1 .
Clinical data of the patients.