- Email: [email protected]
Multicenter clinical trial of Norian SRS versus conventional therapy in the treatment of distal radius fractures: Results from multicenter clinical trial
MULTICENTER CLINICAL TRIAL OF NORIAN SRS VERSUS CONVENTIONAL THERAPY IN THE TREATMENT OF DISTAL RADIUS FRACTURES: RESULTS FROM MULTICENTER CLINICAL TRIAL J. Husband’, C. Cassidy’, C. Leinberry3, M.S. Cohen4, J. Jupite?, M. McQueen6, W. Seitz’ ‘Park Nicollet Medical Center, St. Louis Park, MN *New England Medical Center, Boston, MA, 3Commonwealth Orthopaedic Associates, Reading, PA, 4Rush-Presbyterian-St. Luke’s Medical Center, Rush University, Chicago, IL, ‘Massachusetts General Hospital, Boston, MA, bRoyal Infirmary of Edinburgh, Edinburgh, Scotland. ‘Mt. Sinai Medical Center, Cleveland, OH INTRODUCTION: A prospective randomized multicenter trial was conducted to evaluate functional and radiographic results in unstable distal radius fractures using a carbonated apatite cement (Norian SRS) compared to conventional therapy. The ability of patients treated with cement to mobilize earlier than conventionally treated patients was evaluated. MATERIALS AND METHODS: Randomization was baed on: hand dominance, bone density, fracture classification (AO), and conventional therapy (external fixation or cast). Patients were identified for appropriate conventional therapy then randomized into experimental (SRS) or control. SRS patients were. implanted through a percutaneous or modified open procedure. Casting or external fixation in the control patients was applied with or without Kwires. The SRS cohort’ casts were removed at two weeks with subsequent splinting. The controls were immobilized between 6 to 8 weeks. Postoperative evaluations were 1, 2, 4, 6 weeks, and 3, 6, 12 months consisting of independent radiographic review and functional evaluation. RESULTS: The 323 subjects continue to complete radiographic and functional evaluation for 12 months. To date, the mean age for 300 subjects is 64 years. Fifty percent had a dominant hand injury and 46% in both groups had an intra-articular fracture. In the control patients, 64% were casted and 36% received external fixation. At 6 months, loss of radial length was 4.92 + 3.99 mm for SRS patients and 4.19 f 3.73 mm for the controls. Early functional parameters were measurable in SRS patients at the 2 week cast removal compared to the controls longer immobilization. At 2 weeks, SRS function compared to the contralateral was 75% pronation, 38% supination, 43% flexion, and 36% extension. At 6 weeks, SRS patients were significantly better in all range of motion parameters (p=O.O25). At 6 weeks, SRS patients had significantly higher (35%. p
I I”’ Conference
BIOMECEANICAL EVALUATION OF A CALCIUM PHOSPHATE CEMRNT IN THE FIXATION OF UNSTABLE INTERTROCHANTRRIC FRACTURES D.N. Yetkinler’, S.B. Goodman*, E.S. Reindel’, D. Car@2, R.D. Poser’ ‘Norian Corporation, Cupertino, CA, USA *Stanford University School of Medicine, Stanford, CA, USA INTRODUCTION: Approximately 60% of intertrochanteric fractures arc unstable due to fragmentation of the posteromedial region of the proximal femur (1). Clinically, fractures with a posteromedial defect (PMD) are considered unstable and are more likely to experience varus collapse, proximal femur shortening, malunion, or nonunion after fixation with a sliding hip screw (2). The purpose of this study is to evaluate the proximal femur shortening in this fracture model treated with a sliding hip screw and a calcium phosphate bone cement under simulated physiological loading conditions. MATERIALS AND METHODS: Seven (7) pairs of aged, osteopenic human cadaver femora were used. Femora were prescreened for anatomical deformities and bone mineral density (BMD). A three-part unstable intertrochanteric fracture was created by creating stress risers and loading on a MTS servohydraulic machine. Each femur was implanted with a lag screw and 4-hole sideplate (DHS, Synthes, Paoli, PA). A calcium phosphate cement (Norian SRS, Cupertino, CA) was injected into the intertmchanteric fracture area and posteromedial defect in the test femur. The cement was not injected into the contralateral control femurs. All test femora were placed in an incubator at 37 C” with 100% humidity for 24 hours for proper curing of the cement. The axial load was applied vertically to the femoral head with the shaft oriented in neutral flexion and 12.5 degrees of adduction to simulate the loads experienced in single-leg stance. A Linear Variable Differential Transformer (LVDT) was attached to the protruding end of the lag screw in order to measure relative settling displacement between the sideplate and the lag screw. Each femur was loaded to 220 N ten times at 1 Hz for preconditioning, immediately followed by ten thousand (10,000) cycles of loading to a peak compressive force of 1650 N. RESULTS: Control specimens settled 20.2 216.4 mm (meanfSD) while cement specimens settled 0.91to.8 mm along the axis of the lag screw (p=O.O09). Typically, the failure in the control specimens occurred immediately upon loading for 10,000 cycle and depressed slightly more towards the end of 10,000 cycle. Two of the control specimens did not reach the completion of the 10,000 cycle. Cement specimens settled on average less than 1 mm in a slow steady manner. There was a linear correlation between bone mineral density and settling of the lag screw in the control specimens, r2 = 0.775 while none was found for the cement specimens. CONCLUSION: Clinically relevant settling of the sliding hip screws were obtained in this study. The control specimens settled to its maximum value early in the cyclic loading period. The greater the osteopcnia the more the settling occurred in control specimens. Cement treated specimens settled less than 2 mm. This increased stability was due to filling of the posteromedial defect. The cement stayed intact throughout the experiment and carried physiological load suggesting early weight bearing can be applied to SRS augmented unstable three-part intertrochanteric fractures. 1) Jensen JS.: Acta Orthop Stand, 51:803-810, 1980. 2) Kyle: JBJS 76A:924-50, 1994. CORRESPONDENCE: Duran N. Yetkinler, MD, Ph.D. Norian Corporation 10260 Bubb Road Cupertino, CA 95014-4166 (408) 252-6800 F(408) 252-4211 [email protected]
of the ESB, July 8-1 I 98, Toulouse, France
5
I I”’ Conference
BIOMECEANICAL EVALUATION OF A CALCIUM PHOSPHATE CEMRNT IN THE FIXATION OF UNSTABLE INTERTROCHANTRRIC FRACTURES D.N. Yetkinler’, S.B. Goodman*, E.S. Reindel’, D. Car@2, R.D. Poser’ ‘Norian Corporation, Cupertino, CA, USA *Stanford University School of Medicine, Stanford, CA, USA INTRODUCTION: Approximately 60% of intertrochanteric fractures arc unstable due to fragmentation of the posteromedial region of the proximal femur (1). Clinically, fractures with a posteromedial defect (PMD) are considered unstable and are more likely to experience varus collapse, proximal femur shortening, malunion, or nonunion after fixation with a sliding hip screw (2). The purpose of this study is to evaluate the proximal femur shortening in this fracture model treated with a sliding hip screw and a calcium phosphate bone cement under simulated physiological loading conditions. MATERIALS AND METHODS: Seven (7) pairs of aged, osteopenic human cadaver femora were used. Femora were prescreened for anatomical deformities and bone mineral density (BMD). A three-part unstable intertrochanteric fracture was created by creating stress risers and loading on a MTS servohydraulic machine. Each femur was implanted with a lag screw and 4-hole sideplate (DHS, Synthes, Paoli, PA). A calcium phosphate cement (Norian SRS, Cupertino, CA) was injected into the intertmchanteric fracture area and posteromedial defect in the test femur. The cement was not injected into the contralateral control femurs. All test femora were placed in an incubator at 37 C” with 100% humidity for 24 hours for proper curing of the cement. The axial load was applied vertically to the femoral head with the shaft oriented in neutral flexion and 12.5 degrees of adduction to simulate the loads experienced in single-leg stance. A Linear Variable Differential Transformer (LVDT) was attached to the protruding end of the lag screw in order to measure relative settling displacement between the sideplate and the lag screw. Each femur was loaded to 220 N ten times at 1 Hz for preconditioning, immediately followed by ten thousand (10,000) cycles of loading to a peak compressive force of 1650 N. RESULTS: Control specimens settled 20.2 216.4 mm (meanfSD) while cement specimens settled 0.91to.8 mm along the axis of the lag screw (p=O.O09). Typically, the failure in the control specimens occurred immediately upon loading for 10,000 cycle and depressed slightly more towards the end of 10,000 cycle. Two of the control specimens did not reach the completion of the 10,000 cycle. Cement specimens settled on average less than 1 mm in a slow steady manner. There was a linear correlation between bone mineral density and settling of the lag screw in the control specimens, r2 = 0.775 while none was found for the cement specimens. CONCLUSION: Clinically relevant settling of the sliding hip screws were obtained in this study. The control specimens settled to its maximum value early in the cyclic loading period. The greater the osteopcnia the more the settling occurred in control specimens. Cement treated specimens settled less than 2 mm. This increased stability was due to filling of the posteromedial defect. The cement stayed intact throughout the experiment and carried physiological load suggesting early weight bearing can be applied to SRS augmented unstable three-part intertrochanteric fractures. 1) Jensen JS.: Acta Orthop Stand, 51:803-810, 1980. 2) Kyle: JBJS 76A:924-50, 1994. CORRESPONDENCE: Duran N. Yetkinler, MD, Ph.D. Norian Corporation 10260 Bubb Road Cupertino, CA 95014-4166 (408) 252-6800 F(408) 252-4211 [email protected]
of the ESB, July 8-1 I 98, Toulouse, France
5