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Clinical and radiographic results at five to nine years of cemented, ingrowth and hybrid total hips
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The Journal of Arthroplasty Vol. 8 No. 1 February 1993
Results:. Aspirates f r o m patients w i t h cementless disease inhibited bone cell proliferation an average o f 5 0 % g r e a t e r t h a n aspirates f r o m stable t o t a l hips. The greatest e f f e c t w a s exhibited by digested m e m b r a n e s f r o m loose p r o s t h e s e s , that being seen w i t h the particulates r e t r i e v e d b y e n z y m e digestion. T h e e f f e c t o f p o l y e t h y l e n e is d i f f i c u l t t o evaluate in the aspirate due t o its specific g r a v i t y w h i c h is less t h a n the media in our model. " N o r m a l " hips h a v e particulates in c o n c e n t r a t i o n s t h a t seem to be similar t o hips -with cementless disease e x c e p t for c o n c e n t r a t i o n o f H M W P E . Retrieved specimens o f bone f r o m the i n t e r f a c e c o n f i r m s ' i n vitro data, in t h a t the periprosthetic bone is inhibited. By m R N A analysis the periprosthetic bone is t u r n e d o f f creating " o s t e o b l a s t i c insufficiency" or a lack o f b o n e cell response to m e c h a n i c a l load transfer in the f e m u r . Discuss;ion: The mechanism/s by w h i c h implant w e a r debris a f f e c t s bone cell m e t a b o l i s m is u n k n o w n . It is a p p a r e n t t h a t both in vivo and in vitro findings s u p p o r t an " o s t e o b l a s t i c insufficiency" w h e r e b y bone does n o t respond t o n o r m a l anabolic signals. Data are needed in o r d e r t o d e t e r m i n e the actual c o n c e n t r a t i o n levels in v i v o in o r d e r t o m o r e accurately simulate the conditions during implant service. It is apparent t h a t both catabolic and anabolic f a c t o r s play a role in implant loosening.
Paper#30 A PROSPECTIVE COMPARISON OF T I T ~ N I U M V S . CHROME-COBALT F E M O P ~ H E A D S I N CEMENTLESS TOTAL H I P ARTHROPI21STY Thomas P. Gross, M.D. i, William J. Murzic, M.D. =, Jeffery K. Taylor, M.D. ~, Willia~ L. Bargar, M.D. } J6095 North First St., Fresno, CA 937~01 255 Highland Ave., Salem, MA 01970, }1020 29th Street, #450, Sacramento, CA 95816 Purpose: To examine the problems encountered when using titanium as a bearing surface in cementless THRo Conclusion: Femoral osteolysis was found in 16% of total hip arthroplasties with titanium femoral heads but in no cases using the same implant with a chrome cobalt head at equal follow-up of 4 years. Significance: Titanium should be avoided as a bearing surface in total joint arthroplasty. This is the first clinical series comparing chrome cobalt to titanium bearing surfaces using the same femoral component design. Titanium and its alloys have been implicated in several reports on metallic-wear debris. Polymethylmethacrylate (PMMA) cement, ultra high molecular weight polyethylene (UHMWPE), and metal debris have all been associated with osteolytic lesions and inflammatory membranes around both stable and loose prostheses. The in vitro wear characteristics of titanium alloy against UHMWFE are inferior to cobalt-chrome or ceramic combinations against UHMWPE. Forty-two patients had 51 primary uncemented total hip arthroplasties. One was lost to follow-up. All patients had a titanium alloy custom stem (Techmedica) and a Harris-Galante (Zimmer) acetabular component. The first 25 patients had a femoral head made of titanium alloy (Ti-6AI-4V), the next 25 had chrome-cobalt femoral heads. The titanium head group had an average age of 43 and weight of 150, while the chrome-cobalt head group had an average age of 50 and weight of 174. At 4 year follow-up there were 4 cases with femoral osteolysls in the titanium head group (16%) and none in the chrome-cobalt head group. The follow-up in the titanium head group is approximately 1 year longer than in the cobalt-chrome head group. There have been 3 additional cases of osteolysis in the titanium head group at 5 years of follow-up for a total incidence of 28%. There were 4 loose prostheses in the titanium head group, 2 were due to pad separation from the stem. In the chrome-cobalt head group there was 1 loose prosthesis due to pad separation. stem was revised (5 cases), also were stained darkly. In every re-operation, the acetabular component was found to be well-fixed. There was no evidence of wear o f any of the acetabular liners. There were a total of I0 re-operations, 5 head and liner exchanges for osteolysis with well fixed components, and 5 femoral revisions for loosening (3 with pad separation and 2 for failure of ingrowth). In all reoperated cases where titanium heads were present (9 cases), the prosthetic head appeared burnished; in all but one the articular pseudocapsule was stained gray to black. In the one case where a cobalt-chrome head was encountered, these findings were absent. The femoral
membranes of those cases where the The joint capsule was examined using H&E stains to look for metallic particles, and polarized light microscopy to look for polyethylene. In the cases with titanium heads (9 cases) metallic intracellular articular debris, but no polyethylene debris was found.
Paper #31 CLINICAL AND RADIOGRAPHIC RESULTS AT FIVE TO NINE YEARS OF CEMENTED, INGROWTH AND HYBRID TOTAL HIPS. R.L. Wixson, S.O.
Stulberg, P. Howard, L. Purl (Department of Orthopaedic Surgery, Northwestern University Medical School, Chicago, lllinois). To compare the medium term results of a prospective, non-randomized hip series using both ingrowth and cemented fixation, 221 total hips in 197 patients were performed by two surgeons using identical protocols. Bone ingrowth hips (PCA) were used in men under the age of 70 and women under 60-65. Older patients received either a fully cemented hip or a hybrid where only the femoral component was cemented. Of th~ orlglnal group, 35 patients died, 18 were lost to follow-up and 12 were unable to return. In the original group, there were 45% ingrowth, 32% fully cemented and 23% hybrids. The diagnosis was osteoarthritls in 69%, rheumatoid in 11%, 8% with osteonecrosis, with the remaining having other diagnoses. There 40.2% male and 59.8% female. All ingrowth femoral stems were PCA. There were 135 ingrowth PCA cups and 10 H-G's. The mean ages of the groups were cemented 72, hybrid 68 and ingrowth 60. All x-rays were read by an independent trained observer who was unaware of the clinical outcomes. Pre-operatively the mean Harris score was 66-[ngrowth, 52-cemented and 6S-hybrid. In an initial report of this group at 2-A yrs post-op, the scores were for ingrowth (Harris-93; Pain-42), cement (Harrls-89; Pain43) and hybr!d (Harris-86; Pain-41 ). The incidence of thigh pain was 4%. At maximum folloW-up, the scores were for ingrowth (Harris-93; Pain43), cement (Harris-88; Pain-43) and hybrid (Harris-93; Paln-43). Thigh pain was 6% for uncemented hips and 4% for cemented. The differences in Harris scores were not statistically different when adjusted for other types of disability in the older age group. There were three revisions for recurrent dislocation, four for infection, fo~Jr for loose ingrowth acetabular cups, two for loose femoral ingrowth stems and two for a loose cemented stem. RadiographicaIty 17% of ingrowth PCA cups migrated or rotated, compared to 10% of cemented cups. With uncemented PCA cups, polyethylene wear was thought to cause acetabular osteolysis in 10% of cases and medial femoral lysis in 11% of cases. For the uncemented PCA stems, 12% subsided vs. 3% of the cemented. For the PCA femoral stems, remodelling changes from the 2-4 year follow-up showed an increase in cancellous condensation (13% to 26%) and distal cortical hypertrophy (37% to 45%l. The cemented radiolucencies remained stable over this period. 6% of the PCA stems showed small areas of endosteal lysis. Both" cemented implants and PCA bone ingrowth implants produced early, satisfactory clinlcal results. Loss of ingrowth implant stability and polyethylene wear may occur late and adversely effect the long term results.
Paper #32 OSTEOLYSIS AROUND AN UNCEMENTED CHROME COBALT TOTAL HIP DEVICE: INCIDENCE AND EXTENT AT 7 YEARS IN A PROSPECTIVE STUDY. J. Callaghan, J. Xenos, W. Hopkinson, C. Savory. Walter Reed Army Medical Center, Washington, D.C. PURPOSE: To determine the incidence and extent of osteolysis around the P.C.A. hip arthroplasty in a seu prospectively studied for seven years. CONCLUSION: Osteolysis occurred in 12.6% of hips by seven years with a I0% femoral and 2.6% acetabular incidence. SIGNIFICANCE: This study should provide insight into the classification, natural history, and pathophysi~ogy of destructive bone loss around uncemented hip devices. SUMMARY OF METHOD, RESULTS & DISCUSSION: I03 consecutive uncemented P.C.A. primary total hip arthroplasties were prospectively studied for seven years with clinical hip ratings and hlp and pelvis radiographs. In addition 25 of these hips had serial bone technetium 99 methyldiphosphonate and indium III WBC scans. This group provided the population for determining the incidence and extent as well as time of
The Journal of Arthroplasty Vol. 8 No. 1 February 1993
Results:. Aspirates f r o m patients w i t h cementless disease inhibited bone cell proliferation an average o f 5 0 % g r e a t e r t h a n aspirates f r o m stable t o t a l hips. The greatest e f f e c t w a s exhibited by digested m e m b r a n e s f r o m loose p r o s t h e s e s , that being seen w i t h the particulates r e t r i e v e d b y e n z y m e digestion. T h e e f f e c t o f p o l y e t h y l e n e is d i f f i c u l t t o evaluate in the aspirate due t o its specific g r a v i t y w h i c h is less t h a n the media in our model. " N o r m a l " hips h a v e particulates in c o n c e n t r a t i o n s t h a t seem to be similar t o hips -with cementless disease e x c e p t for c o n c e n t r a t i o n o f H M W P E . Retrieved specimens o f bone f r o m the i n t e r f a c e c o n f i r m s ' i n vitro data, in t h a t the periprosthetic bone is inhibited. By m R N A analysis the periprosthetic bone is t u r n e d o f f creating " o s t e o b l a s t i c insufficiency" or a lack o f b o n e cell response to m e c h a n i c a l load transfer in the f e m u r . Discuss;ion: The mechanism/s by w h i c h implant w e a r debris a f f e c t s bone cell m e t a b o l i s m is u n k n o w n . It is a p p a r e n t t h a t both in vivo and in vitro findings s u p p o r t an " o s t e o b l a s t i c insufficiency" w h e r e b y bone does n o t respond t o n o r m a l anabolic signals. Data are needed in o r d e r t o d e t e r m i n e the actual c o n c e n t r a t i o n levels in v i v o in o r d e r t o m o r e accurately simulate the conditions during implant service. It is apparent t h a t both catabolic and anabolic f a c t o r s play a role in implant loosening.
Paper#30 A PROSPECTIVE COMPARISON OF T I T ~ N I U M V S . CHROME-COBALT F E M O P ~ H E A D S I N CEMENTLESS TOTAL H I P ARTHROPI21STY Thomas P. Gross, M.D. i, William J. Murzic, M.D. =, Jeffery K. Taylor, M.D. ~, Willia~ L. Bargar, M.D. } J6095 North First St., Fresno, CA 937~01 255 Highland Ave., Salem, MA 01970, }1020 29th Street, #450, Sacramento, CA 95816 Purpose: To examine the problems encountered when using titanium as a bearing surface in cementless THRo Conclusion: Femoral osteolysis was found in 16% of total hip arthroplasties with titanium femoral heads but in no cases using the same implant with a chrome cobalt head at equal follow-up of 4 years. Significance: Titanium should be avoided as a bearing surface in total joint arthroplasty. This is the first clinical series comparing chrome cobalt to titanium bearing surfaces using the same femoral component design. Titanium and its alloys have been implicated in several reports on metallic-wear debris. Polymethylmethacrylate (PMMA) cement, ultra high molecular weight polyethylene (UHMWPE), and metal debris have all been associated with osteolytic lesions and inflammatory membranes around both stable and loose prostheses. The in vitro wear characteristics of titanium alloy against UHMWFE are inferior to cobalt-chrome or ceramic combinations against UHMWPE. Forty-two patients had 51 primary uncemented total hip arthroplasties. One was lost to follow-up. All patients had a titanium alloy custom stem (Techmedica) and a Harris-Galante (Zimmer) acetabular component. The first 25 patients had a femoral head made of titanium alloy (Ti-6AI-4V), the next 25 had chrome-cobalt femoral heads. The titanium head group had an average age of 43 and weight of 150, while the chrome-cobalt head group had an average age of 50 and weight of 174. At 4 year follow-up there were 4 cases with femoral osteolysls in the titanium head group (16%) and none in the chrome-cobalt head group. The follow-up in the titanium head group is approximately 1 year longer than in the cobalt-chrome head group. There have been 3 additional cases of osteolysis in the titanium head group at 5 years of follow-up for a total incidence of 28%. There were 4 loose prostheses in the titanium head group, 2 were due to pad separation from the stem. In the chrome-cobalt head group there was 1 loose prosthesis due to pad separation. stem was revised (5 cases), also were stained darkly. In every re-operation, the acetabular component was found to be well-fixed. There was no evidence of wear o f any of the acetabular liners. There were a total of I0 re-operations, 5 head and liner exchanges for osteolysis with well fixed components, and 5 femoral revisions for loosening (3 with pad separation and 2 for failure of ingrowth). In all reoperated cases where titanium heads were present (9 cases), the prosthetic head appeared burnished; in all but one the articular pseudocapsule was stained gray to black. In the one case where a cobalt-chrome head was encountered, these findings were absent. The femoral
membranes of those cases where the The joint capsule was examined using H&E stains to look for metallic particles, and polarized light microscopy to look for polyethylene. In the cases with titanium heads (9 cases) metallic intracellular articular debris, but no polyethylene debris was found.
Paper #31 CLINICAL AND RADIOGRAPHIC RESULTS AT FIVE TO NINE YEARS OF CEMENTED, INGROWTH AND HYBRID TOTAL HIPS. R.L. Wixson, S.O.
Stulberg, P. Howard, L. Purl (Department of Orthopaedic Surgery, Northwestern University Medical School, Chicago, lllinois). To compare the medium term results of a prospective, non-randomized hip series using both ingrowth and cemented fixation, 221 total hips in 197 patients were performed by two surgeons using identical protocols. Bone ingrowth hips (PCA) were used in men under the age of 70 and women under 60-65. Older patients received either a fully cemented hip or a hybrid where only the femoral component was cemented. Of th~ orlglnal group, 35 patients died, 18 were lost to follow-up and 12 were unable to return. In the original group, there were 45% ingrowth, 32% fully cemented and 23% hybrids. The diagnosis was osteoarthritls in 69%, rheumatoid in 11%, 8% with osteonecrosis, with the remaining having other diagnoses. There 40.2% male and 59.8% female. All ingrowth femoral stems were PCA. There were 135 ingrowth PCA cups and 10 H-G's. The mean ages of the groups were cemented 72, hybrid 68 and ingrowth 60. All x-rays were read by an independent trained observer who was unaware of the clinical outcomes. Pre-operatively the mean Harris score was 66-[ngrowth, 52-cemented and 6S-hybrid. In an initial report of this group at 2-A yrs post-op, the scores were for ingrowth (Harris-93; Pain-42), cement (Harrls-89; Pain43) and hybr!d (Harris-86; Pain-41 ). The incidence of thigh pain was 4%. At maximum folloW-up, the scores were for ingrowth (Harris-93; Pain43), cement (Harris-88; Pain-43) and hybrid (Harris-93; Paln-43). Thigh pain was 6% for uncemented hips and 4% for cemented. The differences in Harris scores were not statistically different when adjusted for other types of disability in the older age group. There were three revisions for recurrent dislocation, four for infection, fo~Jr for loose ingrowth acetabular cups, two for loose femoral ingrowth stems and two for a loose cemented stem. RadiographicaIty 17% of ingrowth PCA cups migrated or rotated, compared to 10% of cemented cups. With uncemented PCA cups, polyethylene wear was thought to cause acetabular osteolysis in 10% of cases and medial femoral lysis in 11% of cases. For the uncemented PCA stems, 12% subsided vs. 3% of the cemented. For the PCA femoral stems, remodelling changes from the 2-4 year follow-up showed an increase in cancellous condensation (13% to 26%) and distal cortical hypertrophy (37% to 45%l. The cemented radiolucencies remained stable over this period. 6% of the PCA stems showed small areas of endosteal lysis. Both" cemented implants and PCA bone ingrowth implants produced early, satisfactory clinlcal results. Loss of ingrowth implant stability and polyethylene wear may occur late and adversely effect the long term results.
Paper #32 OSTEOLYSIS AROUND AN UNCEMENTED CHROME COBALT TOTAL HIP DEVICE: INCIDENCE AND EXTENT AT 7 YEARS IN A PROSPECTIVE STUDY. J. Callaghan, J. Xenos, W. Hopkinson, C. Savory. Walter Reed Army Medical Center, Washington, D.C. PURPOSE: To determine the incidence and extent of osteolysis around the P.C.A. hip arthroplasty in a seu prospectively studied for seven years. CONCLUSION: Osteolysis occurred in 12.6% of hips by seven years with a I0% femoral and 2.6% acetabular incidence. SIGNIFICANCE: This study should provide insight into the classification, natural history, and pathophysi~ogy of destructive bone loss around uncemented hip devices. SUMMARY OF METHOD, RESULTS & DISCUSSION: I03 consecutive uncemented P.C.A. primary total hip arthroplasties were prospectively studied for seven years with clinical hip ratings and hlp and pelvis radiographs. In addition 25 of these hips had serial bone technetium 99 methyldiphosphonate and indium III WBC scans. This group provided the population for determining the incidence and extent as well as time of