ABSTRACT Distal fixation with extensively porous-coated stems has demonstrated good fixation, but... more ABSTRACT Distal fixation with extensively porous-coated stems has demonstrated good fixation, but a high incidence of proximal stress-shielding. Proximal femoral fixation was developed to load the femur proximally to avoid the problem of stress-shielding. First generation proximal fixation stems had a high percentage of thigh pain and loosening. Second generation designs with mechanical fixation only in the diaphysis (smooth distal stems) improved fixation, but still demonstrated a relatively high incidence of thigh pain. It is now evident that biologic fixation is required in the diaphysis. Still, proximal fixation must occur in the cortical bone of the proximal femur. Stems with a geometry that primarily load the proximal femur, and yet achieve biologic (osseous) fixation in the diaphysis, result in ‘transitional stress transfer’ to the femur. Contemporary designs that employ these principles are successful in providing durable fixation, a low incidence of thigh pain, and avoid the problem of stress-shielding.
Clinical Orthopaedics and Related Research, Oct 1, 1996
This study was conducted to compare postoperative total knee arthroplasty rehabilitation protocol... more This study was conducted to compare postoperative total knee arthroplasty rehabilitation protocols. The hypothesis of this study was that patients undergoing total knee arthroplasty could achieve range of motion and hospital discharge in the same period using a postoperative rehabilitation protocol that did not use a continuous passive motion machine. This randomized prospective study compared 46 total knee arthroplasties in which a continuous passive motion machine was used with 37 total knees that were rehabilitated with early passive flexion of the knee (named drop and dangle protocol). Postoperative physical therapy regimens were otherwise the same for both groups. Surgical technique was the same for both groups except for closure which was performed in the drop and dangle group with the knee at 90 degrees to 95 degrees flexion. Only patients with osteoarthritis were included in the study, and in both groups of patients received the same prosthetic components. Patients in the drop and dangle group were discharged from the hospital 1 day earlier (p = 0.01) and had a statistically better extension range of 2.8 degrees at 6 months (p = 0.03). Knees in the drop and dangle group had less drainage (p = 0.06). Range of motion and hospital discharge can be achieved in a similar time interval with the drop and dangle technique as with using a continuous passive motion device, and that such a device is not required for postoperative knee rehabilitation.
Although constrained acetabular liners have been successfully used for the treatment of recurrent... more Although constrained acetabular liners have been successfully used for the treatment of recurrent hip instability, their usage has led to a growing number of associated complications. Twenty-seven patients (29 hips) who experienced failure of the constrained acetabular construct were retrospectively reviewed to define mechanisms of failure. Of these patients, 8 had a recurrent failure of another constrained liner. The 4 modes of failure were failure of fixation to the pelvis, liner dissociation, biomaterial failure, and femoral head dislocation. As constrained liners are highly subject to mechanical overload, the risk of failure can be minimized by reducing prosthetic impingement and avoiding technical errors.
Based primarily on in vitro biomechanical studies, most total knee arthroplasty (TKA) manufacture... more Based primarily on in vitro biomechanical studies, most total knee arthroplasty (TKA) manufacturers have abandoned the all-polyethylene tibial component (APT) in favor of the metal-backed tibial component (MBT). There is little clinical evidence to support this decision. A retrospective review of cemented TKA using the total condylar prosthesis was performed. One hundred eighteen patients with 131 TKAs were evaluated. Sixty-two of these knee prostheses had tibial components made entirely of polyethylene while 69 had the MBT. There were 13 cases of bilateral TKA in which the APT was used for one knee and the MBT for the other. All patients were examined by the authors for an average follow-up period of six years. Hospital for Special Surgery knee scores and a comprehensive roentgenographic evaluation were obtained. No significant difference was noted between the patients with APT and those with MBT, raising serious doubt on the need for the MBT in patients being treated with primary, cemented TKA.
The question has been raised as to whether small incision surgery will compromise long term resul... more The question has been raised as to whether small incision surgery will compromise long term results of total hip arthroplasty. We report nine to ten years' outcome with posterior mini-incision. Radiographs were measured for component position, polyethylene wear, fixation, and osteolysis. Sixty-two of the original 86 patients (76 of 100 hips) were alive and available for study with 17 patients deceased (with known results) and seven (8%) lost to follow-up. The result was rated as excellent in 70 of 75 remaining hips (93%). Eighty-nine of 93 hips (96%) with known results had the original implants. Radiographically, wear was a mean 0.015 ± 0.009 mm/year, and no hip had impending failure. There were four revisions, 2 for dislocation, 1 for fracture, and 1 for loose cup.
Page 1. Techniques for preoperative planning and postoperative evaluation of noncemented hip arth... more Page 1. Techniques for preoperative planning and postoperative evaluation of noncemented hip arthroplasty Paul H. Dossick, MD, Lawrence D. Dorr, MD, Thomas Gruen, MS, and Mohammad T. Saberi, MS Л technique is standardized ...
Surgeons want to perform a perfect total hip replacement (THR) with every operation. Human perfor... more Surgeons want to perform a perfect total hip replacement (THR) with every operation. Human performance has limitations, especially when performing a mechanical operation in a biological environment. Recent suggested changes to improve outcomes have been large femoral heads and anterior incisions, but unfortunately neither has resulted in any scientific data that change has been effected. The scientific data does tell us that poor component positions and impingement are the source of increasing mechanical complications. Therefore, attempts to improve the surgeon's performance by precise quantitative knowledge in the operating room have been used. We discuss robotic guided navigation as a solution. This technology provides predictable and reproducible results.
... Auteur(s) / Author(s). DORR Lawrence D. (1) ; CALLAGHAN John J. (1) ; WHITESIDE Leo A. (1) ; ... more ... Auteur(s) / Author(s). DORR Lawrence D. (1) ; CALLAGHAN John J. (1) ; WHITESIDE Leo A. (1) ; ENGH Charles A. (1) ; CAMERON Hugh U. (1) ; MALLORY Thomas H. (1) ; Affiliation(s) du ou des auteurs / Author(s) Affiliation(s). ...
Between 1984 and 1986, 10 patients who sustained a femur fracture about a hip prosthesis were tre... more Between 1984 and 1986, 10 patients who sustained a femur fracture about a hip prosthesis were treated with open reduction and internal fixation using compression plating. Nine of the 10 fractures healed in an average time of 5 months. Other than one nonunion, no significant complications were noted. Follow-up study, ranging from 13 to 44 months (average, 26 months), was obtained on all 10 patients. One had a loose femoral component, which was attributed to inadequate stem size. None of the other patients had either clinical or radiographic evidence of loosening. Based on Harris hip scores, there was no indication that plating significantly interfered with hip function. The authors believe that these results demonstrate that plating can be an effective method of treating femoral fractures about hip prostheses.
... Infected Total Knee Arthroplasty Irrigation and Debridement Versus Two-stage Reimplantation S... more ... Infected Total Knee Arthroplasty Irrigation and Debridement Versus Two-stage Reimplantation Steven M. Teeny, MD,* Lawrence Don', MD,-]- Gary Murata, MD ... In seven knees there had been a skin slough or wounddehiscence, and in three knees there was prolonged drainage. ...
One hundred fifteen cervical fractures, 51 thoracic and lumbar major fractures, 214 compression f... more One hundred fifteen cervical fractures, 51 thoracic and lumbar major fractures, 214 compression fractures, and 34 transverse process fractures from Los Angeles County-University of Southern California Medical Center and Rancho Los Amigos Hospital were reviewed. Epidemiology, fracture type, and early results of treatment in terms of musculoskeletal and neurologic stability were studied. Flexion-rotation fractures of the cervical, thoracic, and lumbar spine showed significant loss of reduction when not treated with operative internal fixation. Operative intervention did not influence the neurologic outcome. Laminectomy resulted in progressive deformity and a significantly increased incidence of second operations. Epidemiology indicated changing patterns of fracture.
The Journal of Trauma: Injury, Infection, and Critical Care, 1978
In a study of experimentally induced open tibial or femoral fractures in rats, after either closi... more In a study of experimentally induced open tibial or femoral fractures in rats, after either closing or leaving the wounds open, the animals were given: no antibiotic, cephalothin (Keflin), or penicillin. The rats with wounds closed primarily and receiving no antibiotics had the highest mortality rate (11 of 25) from experimentally produced clostridial myonecrosis. The lowest overall mortality rate (5 of 99) was found in the penicillin-treated groups. The higher mortality rate in the femur fracture groups was probably because of the large muscle mass of the thigh. The importance of ideal anaerobic conditions for producing experimental clostridial myonecrosis is emphasized.
ABSTRACT Distal fixation with extensively porous-coated stems has demonstrated good fixation, but... more ABSTRACT Distal fixation with extensively porous-coated stems has demonstrated good fixation, but a high incidence of proximal stress-shielding. Proximal femoral fixation was developed to load the femur proximally to avoid the problem of stress-shielding. First generation proximal fixation stems had a high percentage of thigh pain and loosening. Second generation designs with mechanical fixation only in the diaphysis (smooth distal stems) improved fixation, but still demonstrated a relatively high incidence of thigh pain. It is now evident that biologic fixation is required in the diaphysis. Still, proximal fixation must occur in the cortical bone of the proximal femur. Stems with a geometry that primarily load the proximal femur, and yet achieve biologic (osseous) fixation in the diaphysis, result in ‘transitional stress transfer’ to the femur. Contemporary designs that employ these principles are successful in providing durable fixation, a low incidence of thigh pain, and avoid the problem of stress-shielding.
Clinical Orthopaedics and Related Research, Oct 1, 1996
This study was conducted to compare postoperative total knee arthroplasty rehabilitation protocol... more This study was conducted to compare postoperative total knee arthroplasty rehabilitation protocols. The hypothesis of this study was that patients undergoing total knee arthroplasty could achieve range of motion and hospital discharge in the same period using a postoperative rehabilitation protocol that did not use a continuous passive motion machine. This randomized prospective study compared 46 total knee arthroplasties in which a continuous passive motion machine was used with 37 total knees that were rehabilitated with early passive flexion of the knee (named drop and dangle protocol). Postoperative physical therapy regimens were otherwise the same for both groups. Surgical technique was the same for both groups except for closure which was performed in the drop and dangle group with the knee at 90 degrees to 95 degrees flexion. Only patients with osteoarthritis were included in the study, and in both groups of patients received the same prosthetic components. Patients in the drop and dangle group were discharged from the hospital 1 day earlier (p = 0.01) and had a statistically better extension range of 2.8 degrees at 6 months (p = 0.03). Knees in the drop and dangle group had less drainage (p = 0.06). Range of motion and hospital discharge can be achieved in a similar time interval with the drop and dangle technique as with using a continuous passive motion device, and that such a device is not required for postoperative knee rehabilitation.
Although constrained acetabular liners have been successfully used for the treatment of recurrent... more Although constrained acetabular liners have been successfully used for the treatment of recurrent hip instability, their usage has led to a growing number of associated complications. Twenty-seven patients (29 hips) who experienced failure of the constrained acetabular construct were retrospectively reviewed to define mechanisms of failure. Of these patients, 8 had a recurrent failure of another constrained liner. The 4 modes of failure were failure of fixation to the pelvis, liner dissociation, biomaterial failure, and femoral head dislocation. As constrained liners are highly subject to mechanical overload, the risk of failure can be minimized by reducing prosthetic impingement and avoiding technical errors.
Based primarily on in vitro biomechanical studies, most total knee arthroplasty (TKA) manufacture... more Based primarily on in vitro biomechanical studies, most total knee arthroplasty (TKA) manufacturers have abandoned the all-polyethylene tibial component (APT) in favor of the metal-backed tibial component (MBT). There is little clinical evidence to support this decision. A retrospective review of cemented TKA using the total condylar prosthesis was performed. One hundred eighteen patients with 131 TKAs were evaluated. Sixty-two of these knee prostheses had tibial components made entirely of polyethylene while 69 had the MBT. There were 13 cases of bilateral TKA in which the APT was used for one knee and the MBT for the other. All patients were examined by the authors for an average follow-up period of six years. Hospital for Special Surgery knee scores and a comprehensive roentgenographic evaluation were obtained. No significant difference was noted between the patients with APT and those with MBT, raising serious doubt on the need for the MBT in patients being treated with primary, cemented TKA.
The question has been raised as to whether small incision surgery will compromise long term resul... more The question has been raised as to whether small incision surgery will compromise long term results of total hip arthroplasty. We report nine to ten years' outcome with posterior mini-incision. Radiographs were measured for component position, polyethylene wear, fixation, and osteolysis. Sixty-two of the original 86 patients (76 of 100 hips) were alive and available for study with 17 patients deceased (with known results) and seven (8%) lost to follow-up. The result was rated as excellent in 70 of 75 remaining hips (93%). Eighty-nine of 93 hips (96%) with known results had the original implants. Radiographically, wear was a mean 0.015 ± 0.009 mm/year, and no hip had impending failure. There were four revisions, 2 for dislocation, 1 for fracture, and 1 for loose cup.
Page 1. Techniques for preoperative planning and postoperative evaluation of noncemented hip arth... more Page 1. Techniques for preoperative planning and postoperative evaluation of noncemented hip arthroplasty Paul H. Dossick, MD, Lawrence D. Dorr, MD, Thomas Gruen, MS, and Mohammad T. Saberi, MS Л technique is standardized ...
Surgeons want to perform a perfect total hip replacement (THR) with every operation. Human perfor... more Surgeons want to perform a perfect total hip replacement (THR) with every operation. Human performance has limitations, especially when performing a mechanical operation in a biological environment. Recent suggested changes to improve outcomes have been large femoral heads and anterior incisions, but unfortunately neither has resulted in any scientific data that change has been effected. The scientific data does tell us that poor component positions and impingement are the source of increasing mechanical complications. Therefore, attempts to improve the surgeon's performance by precise quantitative knowledge in the operating room have been used. We discuss robotic guided navigation as a solution. This technology provides predictable and reproducible results.
... Auteur(s) / Author(s). DORR Lawrence D. (1) ; CALLAGHAN John J. (1) ; WHITESIDE Leo A. (1) ; ... more ... Auteur(s) / Author(s). DORR Lawrence D. (1) ; CALLAGHAN John J. (1) ; WHITESIDE Leo A. (1) ; ENGH Charles A. (1) ; CAMERON Hugh U. (1) ; MALLORY Thomas H. (1) ; Affiliation(s) du ou des auteurs / Author(s) Affiliation(s). ...
Between 1984 and 1986, 10 patients who sustained a femur fracture about a hip prosthesis were tre... more Between 1984 and 1986, 10 patients who sustained a femur fracture about a hip prosthesis were treated with open reduction and internal fixation using compression plating. Nine of the 10 fractures healed in an average time of 5 months. Other than one nonunion, no significant complications were noted. Follow-up study, ranging from 13 to 44 months (average, 26 months), was obtained on all 10 patients. One had a loose femoral component, which was attributed to inadequate stem size. None of the other patients had either clinical or radiographic evidence of loosening. Based on Harris hip scores, there was no indication that plating significantly interfered with hip function. The authors believe that these results demonstrate that plating can be an effective method of treating femoral fractures about hip prostheses.
... Infected Total Knee Arthroplasty Irrigation and Debridement Versus Two-stage Reimplantation S... more ... Infected Total Knee Arthroplasty Irrigation and Debridement Versus Two-stage Reimplantation Steven M. Teeny, MD,* Lawrence Don', MD,-]- Gary Murata, MD ... In seven knees there had been a skin slough or wounddehiscence, and in three knees there was prolonged drainage. ...
One hundred fifteen cervical fractures, 51 thoracic and lumbar major fractures, 214 compression f... more One hundred fifteen cervical fractures, 51 thoracic and lumbar major fractures, 214 compression fractures, and 34 transverse process fractures from Los Angeles County-University of Southern California Medical Center and Rancho Los Amigos Hospital were reviewed. Epidemiology, fracture type, and early results of treatment in terms of musculoskeletal and neurologic stability were studied. Flexion-rotation fractures of the cervical, thoracic, and lumbar spine showed significant loss of reduction when not treated with operative internal fixation. Operative intervention did not influence the neurologic outcome. Laminectomy resulted in progressive deformity and a significantly increased incidence of second operations. Epidemiology indicated changing patterns of fracture.
The Journal of Trauma: Injury, Infection, and Critical Care, 1978
In a study of experimentally induced open tibial or femoral fractures in rats, after either closi... more In a study of experimentally induced open tibial or femoral fractures in rats, after either closing or leaving the wounds open, the animals were given: no antibiotic, cephalothin (Keflin), or penicillin. The rats with wounds closed primarily and receiving no antibiotics had the highest mortality rate (11 of 25) from experimentally produced clostridial myonecrosis. The lowest overall mortality rate (5 of 99) was found in the penicillin-treated groups. The higher mortality rate in the femur fracture groups was probably because of the large muscle mass of the thigh. The importance of ideal anaerobic conditions for producing experimental clostridial myonecrosis is emphasized.
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