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Dissociation of modular shoulder arthroplasty components
Abstracts
J. Shoulder Elbow Surg. Volume 4, Number 1, Part 2
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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.
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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.
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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. 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.