a Departamento de Ortopedia, Santa Casa de São Paulo, São Paulo, SP, Brasil
b Serviço de Ortopedia e Traumatologia, Hospital Israelita Albert Einstein, Universidade Federal de São Paulo (Unifesp), São Paulo, SP,Brasil
c Instituto de Ortopedia, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo (USP), São Paulo, SP, Brasil
d Escola Paulista de Medicina, Universidade Federal de São Paulo (Unifesp), São Paulo, SP, Brasil
Introduction
The glenohumeral joint is the one that most often presentsinstability in the human body (dislocation and subluxation),with an incidence of 17 cases per 100,000 inhabitants peryear.1Anterior instability accounts for approximately 85% ofthe cases of traumatic dislocation. The natural history of thispathological condition after the first episode has been widelystudied and it is known that there are some important factorsthat influence the recurrence rates, such as age, involvementin contact sports, magnitude of the bone defects, ligament lax-ity and time elapsed between the first episode and surgery.2-4Robinson et al.5found a recurrence rate of 55% after 2 years,among patients under the age of 35 years, with a probabilityof 86% for patients aged 15 years and 26% for patients aged 35years.
In the past, the elective option for treating traumaticanterior instability was open surgery, even after the intro-duction of the arthroscopic technique, given that studiesshowed that the latter method led to a higher recurrencerate.6-8Lane et al.6performed arthroscopic capsulorrhaphyand found that the recurrence rate among their 54 patientswas 33%. In the same year, Grana used the transosseoussuture technique that had been introduced by Morgan in1987 and found that the recurrence rate was 44%.7In1997, Godinho et al.8also used transosseous suturing andfound that the recurrence rate among their 79 patients was13.9%.
Studies conducted more recently have shown improve-ments in the clinical results from the arthroscopic tech-nique, particularly with regard to recurrence, with rates of4-18%,2,9-11i.e. equivalent to those from the open tech-nique. These improvements come from better anatomicalknowledge of the pathological condition, greater experienceamong surgeons and evolution of the arthroscopic mate-rial, especially through the emergence of suture anchors,which were introduced by Wolf.12The challenge of dimin-ishing the recurrence rate has meant that improvement ofthe technique has become an objective. A recent biome-chanical study by Kamath et al.13showed that using twoanchors with double loading provided resistance greaterthan or equal to the use of three anchors with singlethreads.
For the surgical treatment to be successful, not only doesan anatomical repair of the Bankart lesion have to be achieved,but also it is fundamental to identify the risk factors that havebeen proved to be associated with failure of arthroscopic treat-ment, such as failure to recognize a glenohumeral bone defector a redundant anterior capsule.3,14The open technique isindicated in cases of extensive bone lesions.
The aim of this study was to evaluate whether usinganchors with double loading for treating traumatic ante-rior instability of the shoulder improves the clinical results,particularly with regard to recurrence, and to compare thistechnique with the results from using anchors loaded with asingle thread.
Materials and methods
This was a retrospective analysis on patients who were treatedat our institution between 2000 and 2010, for arthroscopicrepair of a Bankart lesion. The inclusion criteria were: (1)recurrent traumatic anterior instability of the shoulder; (2)glenoid bone defects and/or Hill-Sachs lesion < 25%; (3) signingof the consent statement specified by the ethics committeesof the hospitals involved. Patients with large humeral andglenoid bone defects, posterior instability, associated rota-tor cuff injuries or previous surgery on the shoulder wereexcluded. Patients with associated SLAP lesions were notexcluded.
Between December 2007 and August 2010, 59 consecu-tive patients (61 shoulders) underwent arthroscopic treatmentof Bankart lesions using metal anchors with double load-ing of high-resistance thread (double group). This group wascompared with a second group formed by 202 patients (206shoulders) who underwent the same procedure between Jan-uary 2000 and November 2005, but with anchors using singleloading (single group). The characteristics of the two groupsare compared in Table 1. The minimum follow-up was 24months.
All of the operations were performed by two surgeons(G.G.G. and J.M.F.) with comparable surgical skills and expe-rience. All of the patients received general anesthesia andregional block of the brachial plexus, and were positioned inlateral decubitus. Lateral and distal traction was applied and
the affected shoulder was maintained at abduction of 30?, flex-ion of 15?and dorsal inclination of the trunk of 30?. We usedclassical arthroscopic portals, with the arthroscope positionedin the anterosuperior portal, instruments applied throughthe anteroinferior portal and irrigation through the posteriorportal. The glenohumeral joint was inspected and the patho-logical condition was verified (Fig. 1). Debridement of the areaof the Bankart lesion was then performed, with decorticationof the anterior border of the glenoid and the adjacent scapularneck, using a motorized shaver. We marked out the points forfixation of the 4 mm metal anchors (Revo, ConMed/Linvatec).The anchors in the double group were loaded with two braidednonabsorbable suture threads (Ethibond no. 2). The anchorsneeded to be positioned at an inclination of 45?in relation tothe surface of the glenoid and forward of the glenoid bordermedially, by up to 3 mm. The first anchor in the right shoulderwas introduced in the five o'clock position and the remain-der with minimum spacing of 1 cm, superiorly. After insertionof each anchor, a curved soft-tissue penetrator (suture hook)was passed through with a no. 1 monofilament thread, firstlythrough the labrum and the anterior branch of the inferiorglenohumeral ligament, at a point located approximately 1 cmcaudally in relation to its respective anchor. The first non-absorbable thread was tied to the monofilament thread andtransported through the tissue. The tissue was tensioned upon
meeting the anchor and five intercalated knots ("Revo" type)were tied for fixation (Fig. 2).
In the case of the patients in the double group, the secondthread of the anchor was passed through in the same manner,with transfixation of the remainder of the tissue that was stillslack (Figs. 3 and 4). This reinforcement improved the effect ofcapsule-ligament retensioning. The other anchors were thenpositioned, until completing the repair on the Bankart lesion.Three anchors were generally used, with six anteroinferiorlabral repair stitches (Fig. 5). When present, SLAP lesions wererepaired in accordance with the type presented.
The patients were immobilized with full-time use of a Vel-peau sling (neutral abduction and internal rotation of 70?)
and were encouraged to perform flexion-extension of theelbow twice a day. Three weeks later, the sling was with-drawn and the patient started a physiotherapy program aimedat achieving passive gains in range of motion, in all direc-tions. Muscle strengthening was started 12 weeks after theoperation, and complete participation in sports activities wasallowed 6 months after the operation.
The clinical assessment and data-gathering were done by aphysician undergoing a specialization program (R4) in shoul-der surgery, and these procedures consisted of a physicalexamination and application of a questionnaire. The patientswere asked about their first episode of instability, the typeof sports practiced and their return to the sport after the
procedure. Their range of motion was measured using agoniometer and this was compared with the contralateralside. The functional scales used were UCLA and Carter-Rowe.Recurrence or surgical failure was defined as a situation inwhich the patient presented some evidence or symptom ofinstability (insecurity, subluxation or dislocation).
For the descriptive statistical analyses and the tests pre-sented in this study, we used the IBM SPSS statistical package,version 19.0.0. In order to test whether the frequencies of thetwo categorical variables presented any degree of indepen-dence, we used the chi-square test. The magnitude of theassociation between pairs of categorical variables was mea-sured by means of Spearman's correlation test. In order totest and measure the degree of correlation of the responsesbetween two variables of continuous nature, Pearson's corre-lation test was used. Because of the need to compare the dataobtained in the two studies, we used Student's t test to ascer-tain the significance of the difference between the means ofthe different samples. However, the t test would show a dif-ference if the variance of the data in the two samples was thesame or different. Therefore, in such cases, the first step wasto test the null hypothesis of equality between the variances.For this, we used Fisher's F test.
Results
There was no statistical difference in the incidence of recur-rence between the group with single loading of anchors (5.83%)and the group with double loading of anchors (7.69%), at theend of the follow-up period (Table 2).
At the end of the study period (after a minimum follow-up of 2 years), the two groups presented similar results inthe good-excellent range, according to the Carter-Rowe crite-ria, although a difference arose when the mean value of theclassification was evaluated (Table 3). According to the UCLAfunctional scale, there was no difference between the groups:mean value for the single group of 33.64 and for the doublegroup, 34.25 (p = 0.178). Presence of a SLAP lesion did not inter-fere with postoperative function.
The patients in the double group presented a mean loss oflateral rotation of 13.93?(p < 0.001) with the arm adducted, in
relation to the contralateral shoulder. With the arm adductedat 90?, the loss was 16.29?(p < 0.001). There was no differencein relation to anterior elevation or medial rotation.
There was a tendency toward greater return to sport atthe same level as before the surgery in the single group, butwithout statistical significance (Table 4). For this analysis, 53patients in the single group and seven in the double group whowere sedentary were excluded.
Discussion
Both groups in the present study had failure rates lower than10%, which is comparable to the success rates in other stud-ies that used anchors with 2 years of follow-up.2,9,16-18Kimet al.19were the only authors to publish a series of patientswith traumatic anterior instability who were treated by meansof arthroscopic repair using anchors with double loading ofthread, and they presented a recurrence rate of 8.9%, whichwas a result very similar to the 7.69% of the present study.However, the success rate was no greater than in the com-parison group of patients treated using anchors with singleloading.
The results achieved in both groups of the present studywere similar to those in literatures,9,19-24when evaluated bymeans of the Carter-Rowe classification, with good and excel-lent results of the order of 90%. Likewise, Kim et al.19obtainedexcellent functional results, with a mean Carter-Rowe scoreof 96.8. However, in comparing the groups of our study, wefound that increasing the number of suture stitches did notcorrelate with improvement of function, especially in evalu-ating the mean Carter-Rowe score, in which there was a worseresult in the group with double loading.
We found an important limitation of range of motion incomparing the results with the contralateral side among thepatients who underwent repairs using anchors with doubleloading, particularly with regard to lateral rotation with abduc-tion. Even though loss of lateral rotation has been found to bepractically universal in series that used anchors with singleloading of thread,2,18we obtained a result that was signifi-cantly better than that of Kim's sample (loss of 7?of externalrotation with abduction).19This may be caused by greater ten-sioning of the anterior capsule. Despite this finding, there wasno correlation between loss of lateral rotation and recurrenceor worse functional scores.
It has been shown in the literature that the results fromarthroscopic repair of Bankart lesions using anchors with onethread deteriorate with the passage of time. Castagna et al.20found a recurrence rate of 23% with a mean follow-up of10.9 years. Van der Linde et al.21recorded a recurrence rateof 35% with 8-10 years of follow-up, which was already 20%after 2 years. We believe that with the use of doubly loadedanchorsthe recurrence rates may be revealed to be lower asthe follow-up period increases. Theoretically, this superiorityhas already been shown in a recent biomechanical study byKamath et al.,13in which the use of two anchors with dou-ble loading presented resistance to failure that was greaterthan or equal to the use of three anchors with a single thread.Longer follow-up will bring better conclusions regarding thishypothesis.
One of the limitations of our study was the discrepancybetween the sample sizes of the two groups, even thoughthey were homogenous in relation to epidemiological charac-teristics. Another issue is that the study was not prospectiveand randomized, which may have generated bias. Nonethe-less, our study is the first comparative study on arthroscopicrepair of traumatic anterior instability using anchors with sin-gle and double loading of thread. Further studies are necessaryin order to clarify and improve the technique for treating thispathological condition.
Conclusion
So far, treatment of traumatic anterior instability usinganchors with double loading of thread does not present anyadvantage in terms of recurrence or functional improvement,in relation to anchors with single loading.
Conflicts of interest
The authors declare no conflicts of interest.
1. Kroner K, Lind T, Jensen J. The epidemiology of shoulderdislocations. Arch Orthop Trauma Surg. 1989;108(5):288-90.2. Voos JE, Livermore RW, Feeley BT, Altchek DW, Williams RJ,Warren RF, et al. Prospective evaluation of arthroscopicBankart repairs for anterior instability. Am J Sports Med.2010;38(2):302-7.3. Boileau P, Villalba M, Héry JY, Balg F, Ahrens P, Neyton L. Riskfactors for recurrence of shoulder instability afterarthroscopic Bankart repair. J Bone Joint Surg Am.2006;88(8):1755-63.4. Porcellini G, Campi F, Pegreffi F, Castagna A, Paladini P.Predisposing factors for recurrent shoulder dislocation afterarthroscopic treatment. J Bone Joint Surg Am.2009;91(11):2537-42.5. Robinson CM, Howes J, Murdoch H, Will E, Graham C.Functional outcome and risk of recurrent instability afterprimary traumatic anterior shoulder dislocation in youngpatients. J Bone Joint Surg Am. 2006;88(11):2326-36.6. Lane JG, Sachs RA, Riehl B. Arthroscopic staplecapsulorrhaphy: a long-term follow-up. Arthroscopy.1993;9(2):190-4.7. Grana WA, Buckley PD, Yates CK. Arthroscopic Bankart suturerepair. Am J Sports Med. 1993;21(3):348-53.8. Godinho GG, Souza JM, Freitas JMA, Santos FM, Vieira AW,João FM. Tratamento da instabilidade anterior do ombroExperiência com a técnica de Morgan. Rev Bras Ortop.1997;32(4):265-71.9. Carreira DS, Mazzocca AD, Oryhon J, Brown FM, Hayden JK,Romeo AA. A prospective outcome evaluation of arthroscopicBankart repairs: minimum 2-year follow-up. Am J Sports Med.2006;34(5):771-7.10. Kim SH, Ha KI, Cho YB, Ryu BD, Oh I. Arthroscopic anteriorstabilization of the shoulder: two to six-year follow-up. J BoneJoint Surg Am. 2003;85(8):1511-8.11. Godinho GG, Franc¸a FO, Freitas JM, Menezes CM, Freire SG,Wanderley AL, et al. Tratamento artroscópico da instabilidadeanterior traumática do ombro: resultados em longo prazo efatores de risco. Rev Bras Ortop. 2008;43(5):157-66.12. Wolf EM. Arthroscopic capsulolabral repair using sutureanchors. Orthop Clin North Am. 1993;24(1):59-69.13. Kamath GV, Hoover S, Creighton RA, Weinhold P, Barrow A,Spang JT. Biomechanical analysis of a double-loaded glenoidanchor configuration: can fewer anchors provide equivalentfixation? Am J Sports Med. 2013;41(1):163-8.14. Burkhart SS, De Beer JF. Traumatic glenohumeral bone defectsand their relationship to failure of arthroscopic Bankartrepairs: significance of the inverted-pear glenoid and thehumeral engaging Hill-Sachs lesion. Arthroscopy.2000;16(7):677-94.15. Triola MF. Elementary statistics: technology update. 11th ed.Boston: Addison Wesley; 2010.16. Thal R, Nofziger M, Bridges M, Kim JJ. Arthroscopic Bankartrepair using knotless or bioknotless suture anchors: 2- to7-year results. Arthroscopy. 2007;23(4):367-75.17. Hantes ME, Venouziou AI, Liantsis AK, Dailiana ZH, MalizosKN. Arthroscopic repair for chronic anterior shoulderinstability: a comparative study between patients withBankart lesions and patients with combined Bankart andSLAP. Am J Sports Med. 2009;37(6):1093-8.18. Netto NA, Tamaoki MJ, Lenza M, dos Santos JB, MatsumotoMH, Faloppa F, et al. Treatment of Bankart lesions intraumatic anterior instability of the shoulder: a randomizedcontrolled trial comparing arthroscopy and open techniques.Arthroscopy. 2012;28(7):900-8.19. Kim KC, Shin HD, Cha SM, Kim JH. Arthroscopicdouble-loaded single-row repair in chronic traumatic anteriorshoulder dislocation. Arch Orthop Trauma Surg.2012;132(10):1515-20.20. Castagna A, Markopoulos N, Conti M, Delle Rose G,Papadakou E, Garofalo R. Arthroscopic Bankart suture-anchorrepair: radiological and clinical outcome at minimum 10years of follow-up. Am J Sports Med. 2010;38(10):2012-6.21. Van der Linde JA, Van Kampen DA, Terwee CB, Dijksman LM,Kleinjan G, Willems WJ. Long-term results after arthroscopicshoulder stabilization using suture anchors: an 8- to 10-yearfollow-up. Am J Sports Med. 2011;39(11):2396-403.22. Yan H, Cui GQ, Wang JQ, Tian DX, Ao YF. Arthroscopic Bankartrepair with suture anchors: results and risk factors ofrecurrence of instability. Zhonghua Wai Ke Za Zhi.2011;49(7):597-602.23. Zaffagnini S, Marcheggiani Muccioli GM, Giordano G,Bonanzinga T, Grassi A, Nitri M, et al. Long-term outcomesafter repair of recurrent post-traumatic anterior shoulderinstability: comparison of arthroscopic transglenoid sutureand open Bankart reconstruction. Knee Surg SportsTraumatol Arthrosc. 2012;20(5):816-21.24. Mahiro?gullari M, Ozkan H, Akyüz M, U?gras¸ AA, Güney A,Kus¸kucu M. Comparison between the results of open andarthroscopic repair of isolated traumatic anterior instabilityof the shoulder. Acta Orthop Traumatol Turc. 2010;44(3):180-5.
