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Comparison of an arthroscopic and an open procedure for posttraumatic instability of the shoulder: A prospective, randomized multicenter study
Comparison of an arthroscopic and an open procedure for posttraumatic instability of the shoulder: A prospective, randomized multicenter study Anders Sperber, MD, PhD,a Per Hamberg, MD, PhD,b Jon Karlsson, MD, PhD,c Leif Swärd, MD, PhD,c and Torsten Wredmark, MD, PhD,d Eskilstuna, Stockholm, Göteborg, and Huddinge, Sweden
From 1993 through 1996, a multicenter study was conducted on the surgical treatment of patients with posttraumatic recurrent anterior shoulder dislocations. Fifty-six patients (40 men, 16 women; mean age 26 years [range 18-51 years]), were evaluated with shoulder arthroscopy. If a Bankart lesion was present, the patients were randomly allocated to either an arthroscopic reconstruction with the use of biodegradable tacks or an open reconstruction with suture anchors. The postoperative rehabilitation protocol for the two groups was identical. In all patients, the range of shoulder motion, stability, and the Constant and Rowe scores were evaluated at 3, 12, and 24 months postoperatively. Thirty patients were surgically treated with the arthroscopic technique and 26 patients with the open technique. In the arthroscopic group, there were recurrences in 7 (23%) of 30 patients at a mean of 13 months (range 5 to 21 months) after surgery. All patients with stable shoulders had a negative apprehension test result. In the open group, there were recurrences in 3 (12%) of 26 patients at a mean of 10 months (range 2 to 23 months) after surgery (P = not significant). In the arthroscopic group, 2 patients had new traumatic redislocations, whereas 1 patient redislocated during an epileptic seizure. In the open group, 1 traumatic redislocation occurred. The 2-year results in this study demonstrate a large number of redislocations after reconstruction, even in the open surgery group. Patient noncompliance with the rehabilitation protocol and predisposing disease may partially explain these results. A tendency was seen toward more redislocations in the arthroscopic group, which emphasizes the importance of correct patient selection and careful surgical technique in the difficult surgical procedure. (J Shoulder Elbow Surg 2001;10:105-8.) From Mälarhospital Eskilstuna,a Stockholm Söder Hospital,b Sahlgrenska University Hospital Göteborg,c and Huddinge University Hospital,d Sweden. Reprint requests: Anders Sperber, MD, PhD, Department of Orthopaedics, Mälarhospital, SE–631 88 Eskilstuna, Sweden (E-mail: [email protected]). Copyright © 2001 by Journal of Shoulder and Elbow Surgery Board of Trustees. 1058-2746/2001/$35.00 + 0 32/1/112019 doi:10.1067/mse.2001.112019
INTRODUCTION In 1938, Bankart1 reported on his series of 27 patients with anterior shoulder instability who underwent reattachment of the anterior capsulolabral complex. The shoulders of all these patients were judged as stable at follow-up, but the postoperative observation period was not noted. Since then, open Bankart repair, although technically demanding, has proven itself to be a reliable and reproducible method of treatment. In most series, recurrence rates vary between 0% and 10% at the 2-year follow-up.8,13,16 In the past 2 decades, arthroscopic techniques have evolved for the Bankart repair. Initial experience (eg, with metal stapling) was disappointing,4,5,7,9,11 and therefore interest has subsequently focused on transglenoid suturing or intra- or extra-articular fixation with screws, absorbable tacks, or suture anchors.* The results for these methods vary sharply with reported recurrence rates of 0% to 49% (Table I). All these studies, however, have been nonrandomized and conducted at centers specializing in shoulder surgery. The goal of this study was to compare the arthroscopic and the open Bankart repairs. Therefore a prospective, randomized multicenter study with strict inclusion and exclusion criteria was conducted in which only experienced shoulder surgeons were involved. PATIENTS AND METHODS From 1993 through 1996, a multicenter study was conducted on the surgical treatment of patients who had posttraumatic recurrent anterior shoulder dislocations. Fifty-six patients were included in the study. All had recurrent instability after a primary dislocation. Descriptive data on the patient groups are presented in Table II. The study was prospective, randomized, and conducted in a multicenter fashion by 7 experienced shoulder surgeons. To be included in the study, patients had to be 18 years or older with unilateral, recurrent posttraumatic anterior shoulder dislocations or subluxations with an arthroscopically verified Bankart lesion. The exclusion criteria were a primary dislocation less than 3 months old, a bony Bankart lesion >5 mm, generalized joint laxity, “unstable shoulder” even before traumatic dislocation, bilateral instability, multidirectional instability, and an additional soft-tissue injury that could affect joint stability. *References 2, 3, 6, 10, 12, 15, 18-20.
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Table I Review of previously published results for open and arthroscopic reconstruction for correction of recurrent anterior shoulder instability Study
Technique
Bankart, 19381 Morrey, 19753 Rowe, 19782 Hovelius, 19794 Morgan, 198710 Caspari, 199111 Benedetto, 199212 Landsiedl, 199213 Grana, 199314 Walch, 199515 Matthews, 19885 Hawkins, 19896 Detrisac, 19917 Coughlin, 19928 Lane, 19939 Wolf, 198816 Wiley, 198817 Resch, 199718
Number
Open suturing Open suturing Open suturing Open suturing Transglenoid suturing Transglenoid suturing Transglenoid suturing Transglenoid suturing Transglenoid suturing Transglenoid suturing Staple capsulorraphy Staple capsulorraphy Staple capsulorraphy Staple capsulorraphy Staple capsulorraphy Screw and washer Removable rivet Extra-articular screw or tack
Table II Descriptive data of patients surgically treated with an arthroscopic or an open reconstruction Arthroscopic group
Open group
30 21/9 25 (18-51) 21/9 21 1 7 22 4.8
26 19/7 27.5 (19-45) 12/14 11 1 7 18 3.5
1/2 2/26 3/2 — — — —
— — — 1/1 2/2 3/20 4/3
Number of patients Gender (M/F) Age (y) Affected side (R/L) Affected dominant side Subluxations Less than 5 dislocations More than 6 dislocations Time from trauma to surgery (y) Number of tacks/shoulder Number of anchors/shoulder
Consecutive patients admitted for surgery because of anterior shoulder instability gave their informed consent to participate in the study. All patients underwent general anesthesia and were positioned in the beach-chair position during surgery. If arthroscopy through the standard dorsal portal revealed a Bankart lesion suitable for an arthroscopic fixation, the patient was included in the study. The operative procedure was randomized by closed envelopes to either an arthroscopic reconstruction with intra-articular labrum fixation by absorbable tacks (Suretac, Smith & Nephew, Inc, Andover, Mass) or to a standard open reconstruction. In the arthroscopic operation, the optimal number of tacks was estimated by the surgeon. In the open reconstruction, a delto-pectoral approach was used with an L incision through the upper two thirds of the subscapularis tendon and a lateral T incision in the joint capsule. Extracapsular fixation was performed with a free choice of
27 176 145 46 25 49 22 65 27 59 50 50 148 47 54 23 10 100
Follow-up (months) ? 122 72 18-120 17 24-72 29 35 36 49 36 39 48 48 39 5-26 6-24 35
Recurrence (%) 0 11 3.5 2 0 ? 0 14 44 49 12 16 11 25 33 0 10 9
suture anchors and a minimal capsular shift, depending on the surgeon’s estimation of the quality of the capsule. The postoperative rehabilitation protocol for the two groups was identical: the arm was in a swath for 3 weeks, and external rotation was gradually increased in weeks 4 through 6. After 6 weeks, unrestricted range of motion was allowed, though overhead motion and contact sports were discouraged for 6 months. Follow-up investigations were performed at 6 weeks and at 3, 12, and 24 months, with evaluations of range of motion, apprehension sign, relocation test, and the Constant and Rowe scores. In the event of recurrence, further follow-up was terminated, and the procedure for that patient was recorded as a failure. Recurrence was defined as a subluxation or a dislocation after surgery, whereas a positive apprehension sign only did not indicate a clinical failure if the patient’s shoulder was otherwise subjectively stable and shoulder function had been restored by the final follow-up evaluation. The χ2 test was used for comparison of the recurrence rate between the two groups and for comparison of the number of preoperative dislocations versus recurrence rate. The Wilcoxon signed rank test was used for comparison of the loss of external rotation in the two groups.
RESULTS Arthroscopic group Data on recurrences and results from the 2-year follow-up on stable shoulders are presented in Table III. Seven (23%) of 30 patients had recurrences at a mean of 13 months (range 5 to 21 months) after surgery. Two recurrences occurred in connection with new severe shoulder injuries (one was a heavy blow in a fist fight, and one was a fall onto an outstretched arm), whereas 5 recurrences were nontraumatic. Six recurrences involved 6 or more dislocations before surgery, and 1 recurrence involved 5 or fewer dislocations (P = not significant). One patient had a single recurrence at 14
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Table III The overall results after arthroscopic and open reconstructions
Recurrences Number* Time after surgery (months) Traumatic redislocations Stable shoulders Number Constant score Rowe score Loss of external rotation† Positive apprehension test result
Arthroscopic group
Open group
7 (23%) 13 (5-21) 2
3 (12%) 10 (2-23) 1
23 100 (82-100) 100 (90-100) 9° 0
23 98 (67-100) 95 (75-100) 10° 3
Presented are recurrences, time between surgery and redislocation, and the type of redislocation. Also shown are functional parameters and apprehension sign in stable shoulders at the 2-year follow-up. *P = .65 (not significant). †P = .94 (not significant).
months after surgery but had a stable shoulder at the 2year follow-up, with Constant and Rowe scores of 100 points each. The procedure for this patient was recorded as a failure. Two patients were treated with a single tack only, and both had stable shoulders at the followup evaluation. One patient sustained an injury to the long thoracic nerve during surgery, resulting in winging of the scapula. This patient, who also had epileptic seizures, soon had recurrences and underwent reoperation with an open technique. One patient underwent reoperation at 6 weeks because of a broken Suretac tack, which was removed arthroscopically. There were no reports of postoperative aseptic arthritis caused by the absorbable tacks.
Open group Three (12%) of 26 patients had recurrences at a mean of 10 months (range 2 to 23 months) after surgery. In one case, the recurrence occurred from a new severe shoulder injury. All recurrences had 6 or more dislocations before surgery (P = not significant). Low Constant and Rowe scores were associated with postoperative pain and, to a lesser degree, limited external rotation. The apprehension sign was positive in 3 shoulders. Three patients had persistent pain, and 1 patient underwent reoperation to remove a loose anchor 8 weeks after the index operation. One patient had a single recurrence at 2 months but had a stable shoulder at the final follow-up evaluation. DISCUSSION On the basis of experience in previous studies, a higher number of recurrences was expected in the arthroscopic group than in the open one. This was numerically confirmed, though the difference found in the present study was not statistically significant (Table I1,8,13,16). Many factors, including patient selection as
well as minor differences regarding surgical technique between the participating shoulder surgeons, may have contributed to this result. In arthroscopic intraarticular fixation, a satisfactory soft tissue grip appears to be vital for a successful stabilization, but, unfortunately, tissue quality can be difficult to assess during arthroscopy. Not only a Bankart lesion, but also elongation of the capsule and a change in tension in the inferior glenohumeral ligament caused by plastic deformation at the primary dislocation, may be present. A superomedial shift in the overstretched capsule appears to be important and could be accomplished by a grasper inserted from a separate superior portal during insertion of the Suretac tack. If the tacks are correctly inserted, the fixation strength of the soft tissue to bone interface should be enough for the estimated ingrowth period of 6 weeks. However, the acute angle required for drilling into the glenoid edge makes it easy to slip and place the bone canals into the glenoid neck, resulting in an insufficient ligament tension. In this study, we experienced a slightly increased recurrence rate after open surgery compared with that in previous reports, in spite of the fact that all the surgeons involved had long experience in shoulder surgery. The reason for the large number of failures is uncertain, but traumatic redislocations in both groups may have produced a worse result than expected. Contradictory opinions exist in terms of the fixation strength of the biodegradable tacks, and there might be an inadequate soft tissue grip by the tacks used in the present study. Norlin14 reported no difference in terms of the recurrence rate between anchors and transosseous sutures in a randomized study, whereas Tamai et al17 reported inferior results from the anchor technique compared with the osteosuture technique. The latter finding was attributed to insufficient capsule-bone contact from the suture anchor, which appears to be a relevant reason for insufficient soft tissue ingrowth. Late recurrences are not uncommon. In our study,
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one recurrence occurred at 23 months after open surgery, and the same goes for the arthroscopic group, in which one recurrence took place at 21 months. Longterm studies have demonstrated late recurrences after 2 years in 18% to 35% in open surgery,13,16 whereas Walch et al18 had late recurrences in 8% after transglenoidal suturing. A 2-year follow-up does not appear to be sufficient for the final assessment of postoperative shoulder stability, though a reasonable observation period is hard to define. Should a new dislocation several years after surgery be regarded as a failure? Recurrences from new and significant trauma situations are not uncommon, as is demonstrated in this and other studies.8,14,16 The question of whether these patients would have sustained an atraumatic redislocation cannot be answered, but in our opinion, early atraumatic recurrences ought to be at least correlated to the surgical procedure. One patient in each group had a single recurrence but had a stable shoulder and was satisfied with the shoulder function at the final follow-up evaluation. The spontaneous healing of an unstable joint is a plausible explanation for this event, but it also appears likely that the surgery had changed the joint stability in a positive but not sufficient way. In this study, we did not find any influence of repeated dislocations on the failure rate when comparing patients with 6 or more dislocations with those with 5 or fewer. If there is such a numeric influence, it could be expected to be related to the primary dislocation, after which repeated dislocations cause permanent damage to the joint capsule. Two patients in the arthroscopic group were treated with a single Suretac tack only. Both had an excellent final result, and we believe that an adequate ligament tension can be accomplished in this fashion, though little protection remains for the Bankart repair should the single Suretac fail. A single tack, although not recommended as a standard, in exceptional cases could be sufficient. The arthroscopic operation with absorbable tacks resulted in less pain and minimal loss of external rotation but also a tendency toward a higher number of redislocations than in the open operation.
J Shoulder Elbow Surg March/April 2001
REFERENCES 1. Bankart ASB. The pathology and treatment of recurrent dislocation of the shoulder joint. Br J Surg 1938;26:23-9. 2. Benedetto KP, Glotzer W. Arthroscopic Bankart procedure by suture technique: indications, technique, results. Arthroscopy 1992;8:111-8. 3. Caspari RB. In: McGinty JB, editor. Operative arthroscopy. New York: Raven Press; 1991. p. 507-15. 4. Coughlin L, Rubinovich M, Johansson J, White B, Greenspoon J. Arthroscopic staple capsulorraphy for anterior shoulder instability. Am J Sports Med 1992;20:253-6. 5. Detrisiac DA. Arthroscopic shoulder staple capsulorraphy for traumatic anterior instability. In: McGinty JB, editor. Operative arthroscopy. New York: Raven Press; 1991. p. 517-28. 6. Grana WA, Buckley PD, Yates CK. Arthroscopic Bankart suture repair. Am J Sports Med 1993;21:348-53. 7. Hawkins RB. Arthroscopic stapling repair for shoulder instability: a retrospective study of 50 cases. Arthroscopy 1989;5:122-8. 8. Hovelius L, Thorling J, Fredin H. Recurrent anterior dislocation of the shoulder: results after the Bankart and Putti-Platt operations. J Bone Joint Surg Am 1979;61:566-9. 9. Lane JG, Sachs RA, Riehl B. Arthroscopic staple capsulorraphy: a long-term follow-up. Arthroscopy 1993;9:190-4. 10. Landsiedl F. Arthroscopic therapy of the shoulder by capsular repair. Arthroscopy 1992;8:296-304. 11. Matthews LS, Vetter WL, Oweida SJ, Spearman J, Helfet DL. Arthroscopic staple capsulorraphy for recurrent anterior shoulder instability. Arthroscopy 1988;4:106-11. 12. Morgan CD, Bodenstab AB. Arthroscopic Bankart suture repair: techniques and early results. Arthroscopy 1987;3:111-22. 13. Morrey BF, Jones JM. Recurrent anterior dislocation of the shoulder: long term follow-up of the Putti-Platt and Bankart procedures. J Bone Joint Surg Am 1976;58:252-6. 14. Norlin R. Use of Mitek ancoring for Bankart repair: a comparative, randomized, prospective study with traditional bone sutures. J Shoulder Elbow Surg 1994;3:381-5. 15. Resch H, Povacz P, Wambacher M, Sperner G, Golser K. Arthroscopic extra-articular Bankart repair for the treatment of recurrent anterior shoulder dislocation. Arthroscopy 1997;2:188-200. 16. Rowe CR, Patel D, Shouthmayd WW. The Bankart procedure: a long term end-result study. J Bone Joint Surg Am 1978;60:1-18. 17. Tamai K, Higashi A, Tanabe T, Hamada J. Recurrences after the open Bankart repair: a potential risk with the use of suture anchors. J Shoulder Elbow Surg 1997;8:38-41. 18. Walch G, Boileau P, Levigne C, Mandrino A, Neyret P, Donell S. Arthroscopic stabilization for recurrent anterior shoulder dislocation: results of 59 cases. Arthroscopy 1995;11:173-9. 19. Wiley AM. Arthroscopy for shoulder instability and a technique for arthroscopic repair. Arthroscopy 1988;4:25-30. 20. Wolf E. Arthroscopic anterior shoulder capsulorraphy. Techniques Orthop 1988;3:67-73.
From 1993 through 1996, a multicenter study was conducted on the surgical treatment of patients with posttraumatic recurrent anterior shoulder dislocations. Fifty-six patients (40 men, 16 women; mean age 26 years [range 18-51 years]), were evaluated with shoulder arthroscopy. If a Bankart lesion was present, the patients were randomly allocated to either an arthroscopic reconstruction with the use of biodegradable tacks or an open reconstruction with suture anchors. The postoperative rehabilitation protocol for the two groups was identical. In all patients, the range of shoulder motion, stability, and the Constant and Rowe scores were evaluated at 3, 12, and 24 months postoperatively. Thirty patients were surgically treated with the arthroscopic technique and 26 patients with the open technique. In the arthroscopic group, there were recurrences in 7 (23%) of 30 patients at a mean of 13 months (range 5 to 21 months) after surgery. All patients with stable shoulders had a negative apprehension test result. In the open group, there were recurrences in 3 (12%) of 26 patients at a mean of 10 months (range 2 to 23 months) after surgery (P = not significant). In the arthroscopic group, 2 patients had new traumatic redislocations, whereas 1 patient redislocated during an epileptic seizure. In the open group, 1 traumatic redislocation occurred. The 2-year results in this study demonstrate a large number of redislocations after reconstruction, even in the open surgery group. Patient noncompliance with the rehabilitation protocol and predisposing disease may partially explain these results. A tendency was seen toward more redislocations in the arthroscopic group, which emphasizes the importance of correct patient selection and careful surgical technique in the difficult surgical procedure. (J Shoulder Elbow Surg 2001;10:105-8.) From Mälarhospital Eskilstuna,a Stockholm Söder Hospital,b Sahlgrenska University Hospital Göteborg,c and Huddinge University Hospital,d Sweden. Reprint requests: Anders Sperber, MD, PhD, Department of Orthopaedics, Mälarhospital, SE–631 88 Eskilstuna, Sweden (E-mail: [email protected]). Copyright © 2001 by Journal of Shoulder and Elbow Surgery Board of Trustees. 1058-2746/2001/$35.00 + 0 32/1/112019 doi:10.1067/mse.2001.112019
INTRODUCTION In 1938, Bankart1 reported on his series of 27 patients with anterior shoulder instability who underwent reattachment of the anterior capsulolabral complex. The shoulders of all these patients were judged as stable at follow-up, but the postoperative observation period was not noted. Since then, open Bankart repair, although technically demanding, has proven itself to be a reliable and reproducible method of treatment. In most series, recurrence rates vary between 0% and 10% at the 2-year follow-up.8,13,16 In the past 2 decades, arthroscopic techniques have evolved for the Bankart repair. Initial experience (eg, with metal stapling) was disappointing,4,5,7,9,11 and therefore interest has subsequently focused on transglenoid suturing or intra- or extra-articular fixation with screws, absorbable tacks, or suture anchors.* The results for these methods vary sharply with reported recurrence rates of 0% to 49% (Table I). All these studies, however, have been nonrandomized and conducted at centers specializing in shoulder surgery. The goal of this study was to compare the arthroscopic and the open Bankart repairs. Therefore a prospective, randomized multicenter study with strict inclusion and exclusion criteria was conducted in which only experienced shoulder surgeons were involved. PATIENTS AND METHODS From 1993 through 1996, a multicenter study was conducted on the surgical treatment of patients who had posttraumatic recurrent anterior shoulder dislocations. Fifty-six patients were included in the study. All had recurrent instability after a primary dislocation. Descriptive data on the patient groups are presented in Table II. The study was prospective, randomized, and conducted in a multicenter fashion by 7 experienced shoulder surgeons. To be included in the study, patients had to be 18 years or older with unilateral, recurrent posttraumatic anterior shoulder dislocations or subluxations with an arthroscopically verified Bankart lesion. The exclusion criteria were a primary dislocation less than 3 months old, a bony Bankart lesion >5 mm, generalized joint laxity, “unstable shoulder” even before traumatic dislocation, bilateral instability, multidirectional instability, and an additional soft-tissue injury that could affect joint stability. *References 2, 3, 6, 10, 12, 15, 18-20.
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J Shoulder Elbow Surg March/April 2001
Table I Review of previously published results for open and arthroscopic reconstruction for correction of recurrent anterior shoulder instability Study
Technique
Bankart, 19381 Morrey, 19753 Rowe, 19782 Hovelius, 19794 Morgan, 198710 Caspari, 199111 Benedetto, 199212 Landsiedl, 199213 Grana, 199314 Walch, 199515 Matthews, 19885 Hawkins, 19896 Detrisac, 19917 Coughlin, 19928 Lane, 19939 Wolf, 198816 Wiley, 198817 Resch, 199718
Number
Open suturing Open suturing Open suturing Open suturing Transglenoid suturing Transglenoid suturing Transglenoid suturing Transglenoid suturing Transglenoid suturing Transglenoid suturing Staple capsulorraphy Staple capsulorraphy Staple capsulorraphy Staple capsulorraphy Staple capsulorraphy Screw and washer Removable rivet Extra-articular screw or tack
Table II Descriptive data of patients surgically treated with an arthroscopic or an open reconstruction Arthroscopic group
Open group
30 21/9 25 (18-51) 21/9 21 1 7 22 4.8
26 19/7 27.5 (19-45) 12/14 11 1 7 18 3.5
1/2 2/26 3/2 — — — —
— — — 1/1 2/2 3/20 4/3
Number of patients Gender (M/F) Age (y) Affected side (R/L) Affected dominant side Subluxations Less than 5 dislocations More than 6 dislocations Time from trauma to surgery (y) Number of tacks/shoulder Number of anchors/shoulder
Consecutive patients admitted for surgery because of anterior shoulder instability gave their informed consent to participate in the study. All patients underwent general anesthesia and were positioned in the beach-chair position during surgery. If arthroscopy through the standard dorsal portal revealed a Bankart lesion suitable for an arthroscopic fixation, the patient was included in the study. The operative procedure was randomized by closed envelopes to either an arthroscopic reconstruction with intra-articular labrum fixation by absorbable tacks (Suretac, Smith & Nephew, Inc, Andover, Mass) or to a standard open reconstruction. In the arthroscopic operation, the optimal number of tacks was estimated by the surgeon. In the open reconstruction, a delto-pectoral approach was used with an L incision through the upper two thirds of the subscapularis tendon and a lateral T incision in the joint capsule. Extracapsular fixation was performed with a free choice of
27 176 145 46 25 49 22 65 27 59 50 50 148 47 54 23 10 100
Follow-up (months) ? 122 72 18-120 17 24-72 29 35 36 49 36 39 48 48 39 5-26 6-24 35
Recurrence (%) 0 11 3.5 2 0 ? 0 14 44 49 12 16 11 25 33 0 10 9
suture anchors and a minimal capsular shift, depending on the surgeon’s estimation of the quality of the capsule. The postoperative rehabilitation protocol for the two groups was identical: the arm was in a swath for 3 weeks, and external rotation was gradually increased in weeks 4 through 6. After 6 weeks, unrestricted range of motion was allowed, though overhead motion and contact sports were discouraged for 6 months. Follow-up investigations were performed at 6 weeks and at 3, 12, and 24 months, with evaluations of range of motion, apprehension sign, relocation test, and the Constant and Rowe scores. In the event of recurrence, further follow-up was terminated, and the procedure for that patient was recorded as a failure. Recurrence was defined as a subluxation or a dislocation after surgery, whereas a positive apprehension sign only did not indicate a clinical failure if the patient’s shoulder was otherwise subjectively stable and shoulder function had been restored by the final follow-up evaluation. The χ2 test was used for comparison of the recurrence rate between the two groups and for comparison of the number of preoperative dislocations versus recurrence rate. The Wilcoxon signed rank test was used for comparison of the loss of external rotation in the two groups.
RESULTS Arthroscopic group Data on recurrences and results from the 2-year follow-up on stable shoulders are presented in Table III. Seven (23%) of 30 patients had recurrences at a mean of 13 months (range 5 to 21 months) after surgery. Two recurrences occurred in connection with new severe shoulder injuries (one was a heavy blow in a fist fight, and one was a fall onto an outstretched arm), whereas 5 recurrences were nontraumatic. Six recurrences involved 6 or more dislocations before surgery, and 1 recurrence involved 5 or fewer dislocations (P = not significant). One patient had a single recurrence at 14
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J Shoulder Elbow Surg Volume 10, Number 2
107
Table III The overall results after arthroscopic and open reconstructions
Recurrences Number* Time after surgery (months) Traumatic redislocations Stable shoulders Number Constant score Rowe score Loss of external rotation† Positive apprehension test result
Arthroscopic group
Open group
7 (23%) 13 (5-21) 2
3 (12%) 10 (2-23) 1
23 100 (82-100) 100 (90-100) 9° 0
23 98 (67-100) 95 (75-100) 10° 3
Presented are recurrences, time between surgery and redislocation, and the type of redislocation. Also shown are functional parameters and apprehension sign in stable shoulders at the 2-year follow-up. *P = .65 (not significant). †P = .94 (not significant).
months after surgery but had a stable shoulder at the 2year follow-up, with Constant and Rowe scores of 100 points each. The procedure for this patient was recorded as a failure. Two patients were treated with a single tack only, and both had stable shoulders at the followup evaluation. One patient sustained an injury to the long thoracic nerve during surgery, resulting in winging of the scapula. This patient, who also had epileptic seizures, soon had recurrences and underwent reoperation with an open technique. One patient underwent reoperation at 6 weeks because of a broken Suretac tack, which was removed arthroscopically. There were no reports of postoperative aseptic arthritis caused by the absorbable tacks.
Open group Three (12%) of 26 patients had recurrences at a mean of 10 months (range 2 to 23 months) after surgery. In one case, the recurrence occurred from a new severe shoulder injury. All recurrences had 6 or more dislocations before surgery (P = not significant). Low Constant and Rowe scores were associated with postoperative pain and, to a lesser degree, limited external rotation. The apprehension sign was positive in 3 shoulders. Three patients had persistent pain, and 1 patient underwent reoperation to remove a loose anchor 8 weeks after the index operation. One patient had a single recurrence at 2 months but had a stable shoulder at the final follow-up evaluation. DISCUSSION On the basis of experience in previous studies, a higher number of recurrences was expected in the arthroscopic group than in the open one. This was numerically confirmed, though the difference found in the present study was not statistically significant (Table I1,8,13,16). Many factors, including patient selection as
well as minor differences regarding surgical technique between the participating shoulder surgeons, may have contributed to this result. In arthroscopic intraarticular fixation, a satisfactory soft tissue grip appears to be vital for a successful stabilization, but, unfortunately, tissue quality can be difficult to assess during arthroscopy. Not only a Bankart lesion, but also elongation of the capsule and a change in tension in the inferior glenohumeral ligament caused by plastic deformation at the primary dislocation, may be present. A superomedial shift in the overstretched capsule appears to be important and could be accomplished by a grasper inserted from a separate superior portal during insertion of the Suretac tack. If the tacks are correctly inserted, the fixation strength of the soft tissue to bone interface should be enough for the estimated ingrowth period of 6 weeks. However, the acute angle required for drilling into the glenoid edge makes it easy to slip and place the bone canals into the glenoid neck, resulting in an insufficient ligament tension. In this study, we experienced a slightly increased recurrence rate after open surgery compared with that in previous reports, in spite of the fact that all the surgeons involved had long experience in shoulder surgery. The reason for the large number of failures is uncertain, but traumatic redislocations in both groups may have produced a worse result than expected. Contradictory opinions exist in terms of the fixation strength of the biodegradable tacks, and there might be an inadequate soft tissue grip by the tacks used in the present study. Norlin14 reported no difference in terms of the recurrence rate between anchors and transosseous sutures in a randomized study, whereas Tamai et al17 reported inferior results from the anchor technique compared with the osteosuture technique. The latter finding was attributed to insufficient capsule-bone contact from the suture anchor, which appears to be a relevant reason for insufficient soft tissue ingrowth. Late recurrences are not uncommon. In our study,
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one recurrence occurred at 23 months after open surgery, and the same goes for the arthroscopic group, in which one recurrence took place at 21 months. Longterm studies have demonstrated late recurrences after 2 years in 18% to 35% in open surgery,13,16 whereas Walch et al18 had late recurrences in 8% after transglenoidal suturing. A 2-year follow-up does not appear to be sufficient for the final assessment of postoperative shoulder stability, though a reasonable observation period is hard to define. Should a new dislocation several years after surgery be regarded as a failure? Recurrences from new and significant trauma situations are not uncommon, as is demonstrated in this and other studies.8,14,16 The question of whether these patients would have sustained an atraumatic redislocation cannot be answered, but in our opinion, early atraumatic recurrences ought to be at least correlated to the surgical procedure. One patient in each group had a single recurrence but had a stable shoulder and was satisfied with the shoulder function at the final follow-up evaluation. The spontaneous healing of an unstable joint is a plausible explanation for this event, but it also appears likely that the surgery had changed the joint stability in a positive but not sufficient way. In this study, we did not find any influence of repeated dislocations on the failure rate when comparing patients with 6 or more dislocations with those with 5 or fewer. If there is such a numeric influence, it could be expected to be related to the primary dislocation, after which repeated dislocations cause permanent damage to the joint capsule. Two patients in the arthroscopic group were treated with a single Suretac tack only. Both had an excellent final result, and we believe that an adequate ligament tension can be accomplished in this fashion, though little protection remains for the Bankart repair should the single Suretac fail. A single tack, although not recommended as a standard, in exceptional cases could be sufficient. The arthroscopic operation with absorbable tacks resulted in less pain and minimal loss of external rotation but also a tendency toward a higher number of redislocations than in the open operation.
J Shoulder Elbow Surg March/April 2001
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