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Transosseous rotator cuff fixation: The weak link? A biomechanical evaluation
$30
58
J. Shoulder Elbow Surg. March/April 1996
Abstracts
CUFF REPAIR IN SHOULDER ARTHROPLASTY. P.M. Rozing. Dept. or Orthopaedics, University of Leiden, The Netherlands.
60
TRANSOSSEOUS ROTATOR CUFF FIXATION: THE WEAK LINK? A BIOMECHANICAL EVALUATION. J. J.P. Warner, MD, G L Caldwell, Jr., MD, M. Miller, MD, D. Boardman, MD, R. Debski, MS, and L Towers, MI), *Center for Sports Med., Univ. of Pittsburgh, Pittsburgh, PA. It has been suggested that the suture fixation to borte may be the "weak link" of transusseous rotator cuff tendon repair (McLaughlin technique) The pu~ose of this study is to assess the cortical thickness of the greater tuberosity, its influence on the ultimate strength of transosseous sutures, atal the effect of a simple augmentation device. Methods: Forty-five fresh frozen human cadaver humeri with an average age of 63 years were studied. Micro-fine radiograplts were made of 35 spools'hens prior to strength testing. The cortical thickness along the lateral aspect of tht~ hitmerus was measured. A bony trough was fashioned in the greater tuberosity and four sutures were placed through drill holes in the latera/cortex in the following configurations: Group A. Drill holes were placed at 10, 20, or 30 millimeters distal to the top of the greater tubernsity and suture pairs were tied over a bone-bridge width of 5 or 10 millimeters. Group B. Two pairs of sutures were placed at a distance of 10nun distaJ to the tip of the greater tuberosity and tied over a 10mm bone-bridge reinforced with a modified plastic button for augmentation, and were compared to similarly placed sutures without augmentation. The suture fixation was then tested to failure at an extension rate of fifty millimeters per minute. Results: There was a significant (p < 0.001) increase in cortical thickness at 10ram, 20tm~ and 30tour distances with means of 0.22mnx 0.36uml, and 0.86ram respectively. This increased cortical width correlated with the increased ultimate strength at each level. The mean ultimate strengths with a bone-bridge of 5t~ii were 69 Newtons (N), 94N, and 247N at 10nmt, 2Omal, and 30mm distances respectively (p < 0.0 I). With a bone-bridge increased to 1Omm there was a sigruficant (p < 0.05) increase in strength from the 10uurt (100N) to the 20nmt (165N) ddstance. Augmentation with sutures tied over a plastic but/on increased the mean strength from 96N to 183N (p < 0.05), Conclusions: Transosseous suture fixation is not necessarily a "weak link" of repairs. In some instaacns of osteoporotic bone, fLxatiou strength may be improved with augmentation. Strength can be significantly increased by more distal placement in the proximal humerus and increased width of the bone-bridge from 5 to 10ram due to the increased cortical thickness distally. This vital concept has been an unrecognized variable in prior investigations and these findings are clinically important in the surgical technique of rotator cuff repair.
61
SONOGRAPHIC EVALUATION OF THE HILL-SACHS LESION. N. Cicak, MD, R. B[lic, MD, D. Delimar, MD, ( Dept. of Orthopaedics, Sch. of Med, Univ. of Zagreb, Croatia). There is no reliable radiographic view for discovering Hifl-Sachs lesion in the p a t i e n t s with r e c u r r e n t a n t e r i o r s h o u l d e r dislocations. The purpose of this study Js to e v a l u a t e the r e l i a b i l i t y of u l t r a s o u n d in d e t e c t i n g Hill-Sachs lesion in comparison with the most used radiographic view, Stryker notch v]ew and with surgery. Sixty two patients with 67 shoulders with history of recurrent anterior shourder dislocation have been i n c l u d e d in the study. S o n o g r a p h i c a n d r a d i o g r a p h i c examinations were performed in 57 men and ] 1 women, with average age of 28,4 years. Eighteen patients underwent surgery by the Bankart procedure. Traumatic initial dislocation of the shoulder was present in 58 patients and atraumatic dislocation in 9 patients. The a v e r a g e age of the initial dis)ocation of the shoulder was 21,2 years, ranging from 10 to 37 years. The overal) accuracy of discovering HilI-Saehs lesion by ultrasound was 87%, by Stryker notch view 64%. The lesion was found in 17 out of 18 patients at surgery. Ultrasound was positive in all 17 patients. The a v e r a g e size of the Hill-Sachs lesion measured by ultrasound was 19,2 mm long, 16,0 m m w i d e a n d 4.1 mm d e e p . Twenty seven shoulders showed a small HilI-Sachs lesion of up to 3 mm deep, 25 shoulders had a moderately sized lesion of 4 to 6 mm in depth and 6 shoulders a large lesion of 7 to 10 mm in depth No lesion extending over 10 mm in depth were seen. Dynamic e v a l u a t i o n of the shoulder with measurements of all three dimensions of the lesion are possible by ultrasound but not with radiography. In a c c o r d a n c e with results of this study the author~ recommend ultrasound as a routine method ]n evaluation nf the Hi(I-Sachs lesion.
In rheumatoid patients with severe destruction of the shoulder the rotator cuff is often thinned or ruptured. It is questionable whether repair of a tear is critical to the success of a nonconstrained shoulder arthroplasty. A prospective study was done of forty-four shoulder replacements in patients with rheumatoid arthritis. At the time of surgery a large cuff tear was present in 20 shoulders and a good repair of the cuff was performed in 9 shoulders. In the other shoulders the repair was considered insufficient. All patients were clinically evaluated preoperatively, at one year follow-up and regularly afterwards upto 13 years using the HSS and Constant scorring system. The minimum follow-up for inclusion in this study was 2 years. Results: Cuff damage and the quality of the repair had a ~ c a n t influence on the postoperative clinical score. The shoulders with a good repair of the rotator cuff improved considerably and continued to improve after the one year follow-up. Shoulders with a persistent cuff tear after surgery tended to worsen after the one year followupo Conclusion: In rheumatoid shoulders an artbroplasty has to be performed before the cuff is destroyed and if there is a rupture a meticulous repair will improve the clinical result.
59
REPETITIVE IX3AD CYCLING OF REPAIRS OF THE ROTATOR CUFF D J Rossouw, B J McElroy, R J Emery, A A Amis - St Mary's Hospital and Imperial College, London ]ntroduc~icu Methods of improving me strength of rotator cuff repak-s have been biomechadically evaluated in cadaverie studies. Sward et al and France et al have shown that augmenting the bone of the greater t'aberosity with ~ificial material provides a better purchase for the sutures of a cuff repair. Gerber tested the components of a cuff repair individually. He recommends a number of 2 braided polyethylene suture material, a modified MasonAllen tendon suture technique and augmentation of the bone of the greater tuberosity to prevent sutures cutting out of the soft bone in this area. The cortical bone of the lateral humerus provides superi~ strength of anchorage for suture matedal or suture anchors. (Wumer et al, R ~ s o u w et al). All the biomechanical tests on rotator cuff repair have been static distraction tests. We wished to test the effect of cyclic motion on cuff repairs, mimicking an in vivo rehabilb ration l:~ograrnme. Methods Seven paL,s of fresh cadaveric shoulders were obtained. Defects in supraspinatus tendon were repaired into a bony trough using No 2 braided polyethylene sutures, a composite tendon suture technique (modified Snyder suttre). Two methods attaching the suture to bone were compared in each pair of shoulders. In method 1, sutures passed tilrongh the greater tubero~ity and were tied on the lateral aspec~ of the tuberc*ity. Method 2 passed sutures through 2 mm drill holes to the lateral humeral cortex, attaching the bone 2.5 cm distal to the greater tuberasity with 2 Mitek G!! anchors. Repairs were tested in an Instron 1122 testing machine, in 30 dog. of si~nulated abduction. Ten cyclical loads were applied to 50 N and increasing the load by 50N for each subsequent ten cycles tiU failure occurred. Stress-strain graphs were plotted. Results Method 1 failed at an average 227N(+/-41), and Method 2 failed at 238 N (+/-80). Distraction of the repairs was marked, and gaps of 18 mm (method 1) and 14-4 mm (method 2) were present when failure occurred. Failure was by suture breakage and cutting into bone. None of the repairs failed at the tendon. Marked gapping of the repair occun'ed at relatively low cyclical loads, but more so when incremental loads were applied. Both the gapping in the repair, and the ultimate failure occurred at lower k~ads than in our previous testing. Conclusion The effect of cyclically loading a rotator cuff rep~" caused it to gap at repaia" site, and to fail at relatively low loads. These findings generate concern regarding the early mobilizatiori of a shoulder following rotator cuff repair.
58
J. Shoulder Elbow Surg. March/April 1996
Abstracts
CUFF REPAIR IN SHOULDER ARTHROPLASTY. P.M. Rozing. Dept. or Orthopaedics, University of Leiden, The Netherlands.
60
TRANSOSSEOUS ROTATOR CUFF FIXATION: THE WEAK LINK? A BIOMECHANICAL EVALUATION. J. J.P. Warner, MD, G L Caldwell, Jr., MD, M. Miller, MD, D. Boardman, MD, R. Debski, MS, and L Towers, MI), *Center for Sports Med., Univ. of Pittsburgh, Pittsburgh, PA. It has been suggested that the suture fixation to borte may be the "weak link" of transusseous rotator cuff tendon repair (McLaughlin technique) The pu~ose of this study is to assess the cortical thickness of the greater tuberosity, its influence on the ultimate strength of transosseous sutures, atal the effect of a simple augmentation device. Methods: Forty-five fresh frozen human cadaver humeri with an average age of 63 years were studied. Micro-fine radiograplts were made of 35 spools'hens prior to strength testing. The cortical thickness along the lateral aspect of tht~ hitmerus was measured. A bony trough was fashioned in the greater tuberosity and four sutures were placed through drill holes in the latera/cortex in the following configurations: Group A. Drill holes were placed at 10, 20, or 30 millimeters distal to the top of the greater tubernsity and suture pairs were tied over a bone-bridge width of 5 or 10 millimeters. Group B. Two pairs of sutures were placed at a distance of 10nun distaJ to the tip of the greater tuberosity and tied over a 10mm bone-bridge reinforced with a modified plastic button for augmentation, and were compared to similarly placed sutures without augmentation. The suture fixation was then tested to failure at an extension rate of fifty millimeters per minute. Results: There was a significant (p < 0.001) increase in cortical thickness at 10ram, 20tm~ and 30tour distances with means of 0.22mnx 0.36uml, and 0.86ram respectively. This increased cortical width correlated with the increased ultimate strength at each level. The mean ultimate strengths with a bone-bridge of 5t~ii were 69 Newtons (N), 94N, and 247N at 10nmt, 2Omal, and 30mm distances respectively (p < 0.0 I). With a bone-bridge increased to 1Omm there was a sigruficant (p < 0.05) increase in strength from the 10uurt (100N) to the 20nmt (165N) ddstance. Augmentation with sutures tied over a plastic but/on increased the mean strength from 96N to 183N (p < 0.05), Conclusions: Transosseous suture fixation is not necessarily a "weak link" of repairs. In some instaacns of osteoporotic bone, fLxatiou strength may be improved with augmentation. Strength can be significantly increased by more distal placement in the proximal humerus and increased width of the bone-bridge from 5 to 10ram due to the increased cortical thickness distally. This vital concept has been an unrecognized variable in prior investigations and these findings are clinically important in the surgical technique of rotator cuff repair.
61
SONOGRAPHIC EVALUATION OF THE HILL-SACHS LESION. N. Cicak, MD, R. B[lic, MD, D. Delimar, MD, ( Dept. of Orthopaedics, Sch. of Med, Univ. of Zagreb, Croatia). There is no reliable radiographic view for discovering Hifl-Sachs lesion in the p a t i e n t s with r e c u r r e n t a n t e r i o r s h o u l d e r dislocations. The purpose of this study Js to e v a l u a t e the r e l i a b i l i t y of u l t r a s o u n d in d e t e c t i n g Hill-Sachs lesion in comparison with the most used radiographic view, Stryker notch v]ew and with surgery. Sixty two patients with 67 shoulders with history of recurrent anterior shourder dislocation have been i n c l u d e d in the study. S o n o g r a p h i c a n d r a d i o g r a p h i c examinations were performed in 57 men and ] 1 women, with average age of 28,4 years. Eighteen patients underwent surgery by the Bankart procedure. Traumatic initial dislocation of the shoulder was present in 58 patients and atraumatic dislocation in 9 patients. The a v e r a g e age of the initial dis)ocation of the shoulder was 21,2 years, ranging from 10 to 37 years. The overal) accuracy of discovering HilI-Saehs lesion by ultrasound was 87%, by Stryker notch view 64%. The lesion was found in 17 out of 18 patients at surgery. Ultrasound was positive in all 17 patients. The a v e r a g e size of the Hill-Sachs lesion measured by ultrasound was 19,2 mm long, 16,0 m m w i d e a n d 4.1 mm d e e p . Twenty seven shoulders showed a small HilI-Sachs lesion of up to 3 mm deep, 25 shoulders had a moderately sized lesion of 4 to 6 mm in depth and 6 shoulders a large lesion of 7 to 10 mm in depth No lesion extending over 10 mm in depth were seen. Dynamic e v a l u a t i o n of the shoulder with measurements of all three dimensions of the lesion are possible by ultrasound but not with radiography. In a c c o r d a n c e with results of this study the author~ recommend ultrasound as a routine method ]n evaluation nf the Hi(I-Sachs lesion.
In rheumatoid patients with severe destruction of the shoulder the rotator cuff is often thinned or ruptured. It is questionable whether repair of a tear is critical to the success of a nonconstrained shoulder arthroplasty. A prospective study was done of forty-four shoulder replacements in patients with rheumatoid arthritis. At the time of surgery a large cuff tear was present in 20 shoulders and a good repair of the cuff was performed in 9 shoulders. In the other shoulders the repair was considered insufficient. All patients were clinically evaluated preoperatively, at one year follow-up and regularly afterwards upto 13 years using the HSS and Constant scorring system. The minimum follow-up for inclusion in this study was 2 years. Results: Cuff damage and the quality of the repair had a ~ c a n t influence on the postoperative clinical score. The shoulders with a good repair of the rotator cuff improved considerably and continued to improve after the one year follow-up. Shoulders with a persistent cuff tear after surgery tended to worsen after the one year followupo Conclusion: In rheumatoid shoulders an artbroplasty has to be performed before the cuff is destroyed and if there is a rupture a meticulous repair will improve the clinical result.
59
REPETITIVE IX3AD CYCLING OF REPAIRS OF THE ROTATOR CUFF D J Rossouw, B J McElroy, R J Emery, A A Amis - St Mary's Hospital and Imperial College, London ]ntroduc~icu Methods of improving me strength of rotator cuff repak-s have been biomechadically evaluated in cadaverie studies. Sward et al and France et al have shown that augmenting the bone of the greater t'aberosity with ~ificial material provides a better purchase for the sutures of a cuff repair. Gerber tested the components of a cuff repair individually. He recommends a number of 2 braided polyethylene suture material, a modified MasonAllen tendon suture technique and augmentation of the bone of the greater tuberosity to prevent sutures cutting out of the soft bone in this area. The cortical bone of the lateral humerus provides superi~ strength of anchorage for suture matedal or suture anchors. (Wumer et al, R ~ s o u w et al). All the biomechanical tests on rotator cuff repair have been static distraction tests. We wished to test the effect of cyclic motion on cuff repairs, mimicking an in vivo rehabilb ration l:~ograrnme. Methods Seven paL,s of fresh cadaveric shoulders were obtained. Defects in supraspinatus tendon were repaired into a bony trough using No 2 braided polyethylene sutures, a composite tendon suture technique (modified Snyder suttre). Two methods attaching the suture to bone were compared in each pair of shoulders. In method 1, sutures passed tilrongh the greater tubero~ity and were tied on the lateral aspec~ of the tuberc*ity. Method 2 passed sutures through 2 mm drill holes to the lateral humeral cortex, attaching the bone 2.5 cm distal to the greater tuberasity with 2 Mitek G!! anchors. Repairs were tested in an Instron 1122 testing machine, in 30 dog. of si~nulated abduction. Ten cyclical loads were applied to 50 N and increasing the load by 50N for each subsequent ten cycles tiU failure occurred. Stress-strain graphs were plotted. Results Method 1 failed at an average 227N(+/-41), and Method 2 failed at 238 N (+/-80). Distraction of the repairs was marked, and gaps of 18 mm (method 1) and 14-4 mm (method 2) were present when failure occurred. Failure was by suture breakage and cutting into bone. None of the repairs failed at the tendon. Marked gapping of the repair occun'ed at relatively low cyclical loads, but more so when incremental loads were applied. Both the gapping in the repair, and the ultimate failure occurred at lower k~ads than in our previous testing. Conclusion The effect of cyclically loading a rotator cuff rep~" caused it to gap at repaia" site, and to fail at relatively low loads. These findings generate concern regarding the early mobilizatiori of a shoulder following rotator cuff repair.