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On the rarity of glenoid component failure
Abstracts
J. Shoulder Elbow Surg. Volume 4, Number 1, Part 2
31
32
$13
DISSOCIATION OF MODULAR SHOULDER ARTHROPLASTY COMPONENTS. F.T.Blevins, MD, X. Deng, MD, P.A. Torzilli, PhD, R.F. Warren, MD,* Univ. of N e w M e x i c o M e d i c a l Center, A l b u q u e r q u e , NM., H o s p i t a l For Special Surgery, N e w York, NY. The p u r p o s e of our study w a s to i d e n t i f y factors w h i c h m a y be r e s p o n s i b l e for i n - v i v o dissociation of m o d u l a r shoulder arthroplasty components. A review of thirteen in-vivo d i s s o c i a t i o n s in t w e l v e p a t i e n t s w a s conducted. R e t r i e v e d c o m p o n e n t s w e r e i n s p e c t e d for d e f e c t s and wear, and w e r e m e c h a n i c a l l y tested. New tapers were used to measure peak axial d i s t r a c t i o n forces u n d e r clean and c o n t a m i n a t e d conditions. The m e a n d i s s o c i a t i o n force w a s 3,133 +- 339 N for r e t r i e v e d h u m e r a l heads, and 3,461 +- 282 N for n e w c o m p o n e n t s (p=.04). All t h i r t e e n r e p o r t e d dissociations except one occurred within the first six w e e k s following surgery. A linear r e l a t i o n s h i p w a s found b e t w e e n i m p a c t i o n force and d i s t r a c t i o n force. T h e r e was a s i g n i f i c a n t i n c r e a s e in t h e d i s t r a c t i o n force w i t h t w o m a l l e t impactions, from a mean of 2,094 +523 N f o l l o w i n g o n e i m p a c t i o n to a m e a n of 2,926 +- 955 N f o l l o w i n g t w o impactions. A d d i t i o n a l i m p a c t i o n s did not i n c r e a s e t h e d i s t r a c t i o n force. F i l l i n g the taper sockets with fluid before mallet i m p a c t i o n c o n s i s t e n t l y d e c r e a s e d the d i s t r a c t i o n force to v e r y low values. F l u i d c o n t a m i n a t i o n of t h e socket is t h e m o s t likely cause of improper taper seating. C o n t a m i n a t i o n of the t a p e r w i t h a small v o l u m e of fluid can p r e v e n t frictional f i x a t i o n of the taper.
33
RHEUMATOIDSHOULDER: HEMI-ARTHROPLASTYVS. TOTAL SHOULDER ARTHROPLASTY. P Kechele MD, C Basamania MD, MA Wirth MD, DG Seltzer MD, CA Rockwood Jr MD. UTHSC-SA, Orthopaedics, 7703 Floyd Curl Dr., San Antonio, TX 78284 The authors retrospectively reviewed 45 shoulders in 37 patients with rheumatoid arthritis. Thirty-two shoulders were treated with a hemiarthroplasty and 13 with a total shoulder arthroplasty. Twenty-four shoulders (53 percent) had an irreparable cuff due to massive defects which were associated with secondary superior migration of the humeral head. Preoperatively, the average active flexion for all shoulders was 50 °, 21 ° of external rotation, and internal rotation to the sacrum. Postoperatively, the average gain in motion for all shoulders was 52 ° of active flexion, 13 ° of external rotation, and 7 spinal levels for internal rotation. Hemiarthroplasty patients had a greater improvement in their postoperative range of motion, with an average gain in flexion of 58 ° , compared to 39 ° in shoulders with a total shoulder arthroplasty. The hemiarthroplasty should be considered over a total shoulder arthroplasty in the management of patients with rheumatoid arthritis. It is easier to perform, can be performed within a shorter operative time, and can be performed in shoulders with deficient supraspinatus and infraspinatus tendons. Furthermore, it eliminates the possibility of glenoid component failure secondary to late disruption of the rotator cuff.
AN ANALYSIS OF FAILED HUMERAL HEAD AND TOTAL SHOULDER ARTHROPLASTY. MA Wirth, MD, DG Seltzer,MD, HR Senes,MD, A Pannone,MD, J Lee,MD, CA Rockwood,MD. UT Medical School, Dept. Orthopaedics, 7703 Floyd Curl Dr., San Antonio, Texas We reviewed 39 consecutive revision shoulder arthroplasties performed on 38 patients at our institution between 1977 and 1993. There were 23 males and 14 females with a mean age of 58 years (range, 27 to 78 years). The index procedure being hemiarthroplasty in 14 shoulders and total shoulder arthroplasty in the remaining 25 shoulders. The initial indication for arthroplasty was trauma in 19 shoulders, osteoarthritis in 13 shoulders, post-reconstructive arthropathy in 5 shoulders, and rheumatoid arthritis in 2 shoulders. Five patients had undergone eight prior attempts at revision arthroplasty. Revision surgery was performed at a mean of 3 years after the index procedure (range, 4 months to 15 years) and consisted of 19 total shoulder arthroplasties, 12 hemiarthroplasties, and 8 resection arthroplasties. The reasons for failure included instability, component loosening, tuberosity detachment or malunion, infection, and deltoid weakness or paralysis. The majority of failures were attributed to errors in surgical technique.
34
ON THE RARITY OF GLENOID COMPONENT FAILURE. Mark W. Rodosky, MD, David M. Weinstein,
MD, Roger G. Pollock, MD, Evan L. Flatow, MD, Louis U. Bigliani, hiD, Charles S. Neer, II, MD. The Shoulder Service, New York Orthopaedic Hospital, ColumbiaPresbyterian Medical Center, New York, New York. Twenty-five patients with glenoid component failure were treated surgically an average of 4 yeats after total shoulder replacement (TSR) (range 5 months - 17 years). Twelve of the twenty-five patients had their original total shoulder replacement at our institution. The remaining 13 patients had been referred to us. The patients' initial diagnoses were posttraumatic arthritis in 10 (following fractures or dislocations), ostcoartlu'itis in 8, avascular necrosis in 3, rheumatoid arthritis in 2, and cull'tear arthropathy in 2. There were 15 males and 10 females, with an average age of 60 years (range: 22-74 years). The dominant extremity was involved in 20 cases (8o%). All patients complained of pain, loss of motion, and functional impairment. The duration of symptoms averaged 10 months. Seven patients developed symptoms after trauma. Review of radiographs showed that six patients had fractured their glenoid component at the base of the stem. Glenoid lucent lines were noted around all 18 unbroken or nondamaged gienoid components (100%), and around 11 humeral stems (44%).
cont.
J. Shoulder Elbow Surg. January~February 1995
$14 Abstracts
34
conf.
At surgery, 17 of the glenoids were grossly loose, and one exhibited micromotion. One additional glenoid was severely worn to its metal backing. The other six components were fractured at the base of the keel which had remained firmly fixed in the glenoid. Three humeral components and two glenoid components were noted to be malaligned. Two of the loose glenoids were infected. Eight of the humeral stems were loose (32%). Of the 12 glenoids originally implanted on our service, 6 were broken, 5 had aseptic loosening, and one was infected and loose. In 9 of these 12 cases, glenoid bone deficiency had been built up with cement, which extruded, leading to toggling and stem fracture in 5 and to loosening in 4 others. The revision procedure involved both components in 14, glenoid component removal in 9 (7 of which also had humeral revision), and removal of both components in two. Twenty-four patients were available for follow-up averaging 5 years (range: 1-17 years). Overall, there were 8 (33%) excellent, 8 (33%) satisfactory, and 8 (33%) unsatisfactory results. Both patients with resection arthroplasty had unsatisfactory results. Pain relief was significantly improved in 19 cases (79%) and showed little or no improvement in 5 cases (21%). Motion and function were significantly improved in 16 cases (66%). Both replacement of the glenoid component and glenoid removal yielded satisfactory results in the majority of patients. The results in the replacement group were slightly better overall, and specifically with respect to pain relief and function than in the removal group. However, a significantly higher percentage of patients in the replacement group (69% vs 33%) had an intact deltoid and rotator cuff. There were 3 reoperatiuns: 2 anterior acromioplasties and one revision for septic loosening of the revised glenoid component. Glenoid component failure following total shoulder replacement (TSR) is uncommon. This series included twelve of our own glenoid components implanted during a period in which over 800 TSR's were performed on our service. Glenoid component revision or simple glenoid component removal both provide satisfactory results with pain improvement in 79%~ Component malalignment or poor bone support were technical factors associated with loosening. The decision whether to reimplant is based on the amount and quality of the remaining glenoid bone stock and the status of the rotator cuff at the time of revision.
35
B I C E P S F U N C T I O N IN N O R M A L A N D R O T A T O R CUFF DEFICIENT SHOULDERS: AN E L E C T R O M Y O G R A P H I C ANALYSIS. K. Yamaguchi, K. D. Riew, L. M. Galatz, J. A. Syme and R. J. Neviaser, The George Washington University Hospital, Dept. Orthopaedic Surgery. I n t r o d u c t i o n : The biceps has been postulated to be a humeral head depressor, which increases in relative importance in the presence of rotator cuff tears, yet its exact role remains controversial. A prerequisite for demonstrating active function is biceps activity coordinated with depressor muscles such as the supraspinatus during shoulder motion. This study was conducted to determine, with electromyography (EMG), if the long head of the biceps brachii has an active role in either normal or rotator cuff deficient shoulder motion. Methods, Results, Discussion: EMG's in 44 shoulders from 30 volunteers were examined. Fourteen shoulders had documented rotator cuff tears with associated loss of abduction strength. The remaining volunteers had normal cuff integrity by history and exam. EMG's were recorded from the lateral biceps, and brachioradialis (elbow control) with surface electrodes and from the supraspinatus (shoulder control) with fine wire electrodes as previously described by Basmajian. Elbow-related biceps activity was minimized by using a brace locked in neutral forearm rotation and 100 deg. of flexion. Volunteers were instructed to concentrate on elevating the arm at the shoulder; they were blinded as to the study goals and thus not specifically asked to relax the biceps. Analysis of normal and rotator cuff deficient data was performed in a blinded fashion. E M G activity expressed as a percent of maximal muscle contraction (MMC) during ten shoulder motions based on the scapular plane. Normal shoulders, in all ranges of active motion, exhibited significant supraspinatus activity (20-50% MMC). The response followed patterns expected for a shoulder stabilizer. In contrast, with every normal shoulder, biceps and brachioradialis activity remained insignificant (1.7-3.6% MMC) and did not follow any patterned response. In all patients with rotator cuff tears although there was a significant increase in supraspinatus activity, biceps remained low (1.6-4.4% MMC). As opposed to previous studies using EMG's about the shoulder, this trial examined shoulder-specific biceps activity by relaxing the elbow. In a comparatively large sampling of normal shoulders, no significant biceps activity was observed in any shoulder. Additionally, no increased activity was seen in patients with rotator cuff tears. Given these findings, it is concluded the biceps does not have an active role in humeral head depression associated with either normal or rotator cuff deficient shoulder motion.
J. Shoulder Elbow Surg. Volume 4, Number 1, Part 2
31
32
$13
DISSOCIATION OF MODULAR SHOULDER ARTHROPLASTY COMPONENTS. F.T.Blevins, MD, X. Deng, MD, P.A. Torzilli, PhD, R.F. Warren, MD,* Univ. of N e w M e x i c o M e d i c a l Center, A l b u q u e r q u e , NM., H o s p i t a l For Special Surgery, N e w York, NY. The p u r p o s e of our study w a s to i d e n t i f y factors w h i c h m a y be r e s p o n s i b l e for i n - v i v o dissociation of m o d u l a r shoulder arthroplasty components. A review of thirteen in-vivo d i s s o c i a t i o n s in t w e l v e p a t i e n t s w a s conducted. R e t r i e v e d c o m p o n e n t s w e r e i n s p e c t e d for d e f e c t s and wear, and w e r e m e c h a n i c a l l y tested. New tapers were used to measure peak axial d i s t r a c t i o n forces u n d e r clean and c o n t a m i n a t e d conditions. The m e a n d i s s o c i a t i o n force w a s 3,133 +- 339 N for r e t r i e v e d h u m e r a l heads, and 3,461 +- 282 N for n e w c o m p o n e n t s (p=.04). All t h i r t e e n r e p o r t e d dissociations except one occurred within the first six w e e k s following surgery. A linear r e l a t i o n s h i p w a s found b e t w e e n i m p a c t i o n force and d i s t r a c t i o n force. T h e r e was a s i g n i f i c a n t i n c r e a s e in t h e d i s t r a c t i o n force w i t h t w o m a l l e t impactions, from a mean of 2,094 +523 N f o l l o w i n g o n e i m p a c t i o n to a m e a n of 2,926 +- 955 N f o l l o w i n g t w o impactions. A d d i t i o n a l i m p a c t i o n s did not i n c r e a s e t h e d i s t r a c t i o n force. F i l l i n g the taper sockets with fluid before mallet i m p a c t i o n c o n s i s t e n t l y d e c r e a s e d the d i s t r a c t i o n force to v e r y low values. F l u i d c o n t a m i n a t i o n of t h e socket is t h e m o s t likely cause of improper taper seating. C o n t a m i n a t i o n of the t a p e r w i t h a small v o l u m e of fluid can p r e v e n t frictional f i x a t i o n of the taper.
33
RHEUMATOIDSHOULDER: HEMI-ARTHROPLASTYVS. TOTAL SHOULDER ARTHROPLASTY. P Kechele MD, C Basamania MD, MA Wirth MD, DG Seltzer MD, CA Rockwood Jr MD. UTHSC-SA, Orthopaedics, 7703 Floyd Curl Dr., San Antonio, TX 78284 The authors retrospectively reviewed 45 shoulders in 37 patients with rheumatoid arthritis. Thirty-two shoulders were treated with a hemiarthroplasty and 13 with a total shoulder arthroplasty. Twenty-four shoulders (53 percent) had an irreparable cuff due to massive defects which were associated with secondary superior migration of the humeral head. Preoperatively, the average active flexion for all shoulders was 50 °, 21 ° of external rotation, and internal rotation to the sacrum. Postoperatively, the average gain in motion for all shoulders was 52 ° of active flexion, 13 ° of external rotation, and 7 spinal levels for internal rotation. Hemiarthroplasty patients had a greater improvement in their postoperative range of motion, with an average gain in flexion of 58 ° , compared to 39 ° in shoulders with a total shoulder arthroplasty. The hemiarthroplasty should be considered over a total shoulder arthroplasty in the management of patients with rheumatoid arthritis. It is easier to perform, can be performed within a shorter operative time, and can be performed in shoulders with deficient supraspinatus and infraspinatus tendons. Furthermore, it eliminates the possibility of glenoid component failure secondary to late disruption of the rotator cuff.
AN ANALYSIS OF FAILED HUMERAL HEAD AND TOTAL SHOULDER ARTHROPLASTY. MA Wirth, MD, DG Seltzer,MD, HR Senes,MD, A Pannone,MD, J Lee,MD, CA Rockwood,MD. UT Medical School, Dept. Orthopaedics, 7703 Floyd Curl Dr., San Antonio, Texas We reviewed 39 consecutive revision shoulder arthroplasties performed on 38 patients at our institution between 1977 and 1993. There were 23 males and 14 females with a mean age of 58 years (range, 27 to 78 years). The index procedure being hemiarthroplasty in 14 shoulders and total shoulder arthroplasty in the remaining 25 shoulders. The initial indication for arthroplasty was trauma in 19 shoulders, osteoarthritis in 13 shoulders, post-reconstructive arthropathy in 5 shoulders, and rheumatoid arthritis in 2 shoulders. Five patients had undergone eight prior attempts at revision arthroplasty. Revision surgery was performed at a mean of 3 years after the index procedure (range, 4 months to 15 years) and consisted of 19 total shoulder arthroplasties, 12 hemiarthroplasties, and 8 resection arthroplasties. The reasons for failure included instability, component loosening, tuberosity detachment or malunion, infection, and deltoid weakness or paralysis. The majority of failures were attributed to errors in surgical technique.
34
ON THE RARITY OF GLENOID COMPONENT FAILURE. Mark W. Rodosky, MD, David M. Weinstein,
MD, Roger G. Pollock, MD, Evan L. Flatow, MD, Louis U. Bigliani, hiD, Charles S. Neer, II, MD. The Shoulder Service, New York Orthopaedic Hospital, ColumbiaPresbyterian Medical Center, New York, New York. Twenty-five patients with glenoid component failure were treated surgically an average of 4 yeats after total shoulder replacement (TSR) (range 5 months - 17 years). Twelve of the twenty-five patients had their original total shoulder replacement at our institution. The remaining 13 patients had been referred to us. The patients' initial diagnoses were posttraumatic arthritis in 10 (following fractures or dislocations), ostcoartlu'itis in 8, avascular necrosis in 3, rheumatoid arthritis in 2, and cull'tear arthropathy in 2. There were 15 males and 10 females, with an average age of 60 years (range: 22-74 years). The dominant extremity was involved in 20 cases (8o%). All patients complained of pain, loss of motion, and functional impairment. The duration of symptoms averaged 10 months. Seven patients developed symptoms after trauma. Review of radiographs showed that six patients had fractured their glenoid component at the base of the stem. Glenoid lucent lines were noted around all 18 unbroken or nondamaged gienoid components (100%), and around 11 humeral stems (44%).
cont.
J. Shoulder Elbow Surg. January~February 1995
$14 Abstracts
34
conf.
At surgery, 17 of the glenoids were grossly loose, and one exhibited micromotion. One additional glenoid was severely worn to its metal backing. The other six components were fractured at the base of the keel which had remained firmly fixed in the glenoid. Three humeral components and two glenoid components were noted to be malaligned. Two of the loose glenoids were infected. Eight of the humeral stems were loose (32%). Of the 12 glenoids originally implanted on our service, 6 were broken, 5 had aseptic loosening, and one was infected and loose. In 9 of these 12 cases, glenoid bone deficiency had been built up with cement, which extruded, leading to toggling and stem fracture in 5 and to loosening in 4 others. The revision procedure involved both components in 14, glenoid component removal in 9 (7 of which also had humeral revision), and removal of both components in two. Twenty-four patients were available for follow-up averaging 5 years (range: 1-17 years). Overall, there were 8 (33%) excellent, 8 (33%) satisfactory, and 8 (33%) unsatisfactory results. Both patients with resection arthroplasty had unsatisfactory results. Pain relief was significantly improved in 19 cases (79%) and showed little or no improvement in 5 cases (21%). Motion and function were significantly improved in 16 cases (66%). Both replacement of the glenoid component and glenoid removal yielded satisfactory results in the majority of patients. The results in the replacement group were slightly better overall, and specifically with respect to pain relief and function than in the removal group. However, a significantly higher percentage of patients in the replacement group (69% vs 33%) had an intact deltoid and rotator cuff. There were 3 reoperatiuns: 2 anterior acromioplasties and one revision for septic loosening of the revised glenoid component. Glenoid component failure following total shoulder replacement (TSR) is uncommon. This series included twelve of our own glenoid components implanted during a period in which over 800 TSR's were performed on our service. Glenoid component revision or simple glenoid component removal both provide satisfactory results with pain improvement in 79%~ Component malalignment or poor bone support were technical factors associated with loosening. The decision whether to reimplant is based on the amount and quality of the remaining glenoid bone stock and the status of the rotator cuff at the time of revision.
35
B I C E P S F U N C T I O N IN N O R M A L A N D R O T A T O R CUFF DEFICIENT SHOULDERS: AN E L E C T R O M Y O G R A P H I C ANALYSIS. K. Yamaguchi, K. D. Riew, L. M. Galatz, J. A. Syme and R. J. Neviaser, The George Washington University Hospital, Dept. Orthopaedic Surgery. I n t r o d u c t i o n : The biceps has been postulated to be a humeral head depressor, which increases in relative importance in the presence of rotator cuff tears, yet its exact role remains controversial. A prerequisite for demonstrating active function is biceps activity coordinated with depressor muscles such as the supraspinatus during shoulder motion. This study was conducted to determine, with electromyography (EMG), if the long head of the biceps brachii has an active role in either normal or rotator cuff deficient shoulder motion. Methods, Results, Discussion: EMG's in 44 shoulders from 30 volunteers were examined. Fourteen shoulders had documented rotator cuff tears with associated loss of abduction strength. The remaining volunteers had normal cuff integrity by history and exam. EMG's were recorded from the lateral biceps, and brachioradialis (elbow control) with surface electrodes and from the supraspinatus (shoulder control) with fine wire electrodes as previously described by Basmajian. Elbow-related biceps activity was minimized by using a brace locked in neutral forearm rotation and 100 deg. of flexion. Volunteers were instructed to concentrate on elevating the arm at the shoulder; they were blinded as to the study goals and thus not specifically asked to relax the biceps. Analysis of normal and rotator cuff deficient data was performed in a blinded fashion. E M G activity expressed as a percent of maximal muscle contraction (MMC) during ten shoulder motions based on the scapular plane. Normal shoulders, in all ranges of active motion, exhibited significant supraspinatus activity (20-50% MMC). The response followed patterns expected for a shoulder stabilizer. In contrast, with every normal shoulder, biceps and brachioradialis activity remained insignificant (1.7-3.6% MMC) and did not follow any patterned response. In all patients with rotator cuff tears although there was a significant increase in supraspinatus activity, biceps remained low (1.6-4.4% MMC). As opposed to previous studies using EMG's about the shoulder, this trial examined shoulder-specific biceps activity by relaxing the elbow. In a comparatively large sampling of normal shoulders, no significant biceps activity was observed in any shoulder. Additionally, no increased activity was seen in patients with rotator cuff tears. Given these findings, it is concluded the biceps does not have an active role in humeral head depression associated with either normal or rotator cuff deficient shoulder motion.