My Orthopaedic Surgeon

Archive Copy - 1999 Annual Meeting Scientific Program. Polyethylene: The Past, Present and Future

NEW YORK (Reuters Health) Apr 02 - A review of studies looking at anticoagulant prophylaxis after hip and knee arthroplasty reveals that not only do these agents fail to completely prevent pulmonary embolism (PE), their use may actually increase all-cause mortality. The results, which appear in the March issue of Clinical Orthopaedics and Related Research (Clin Orthop Relat Res 2008;466:714-721), show that the risk was most pronounced with so-called potent anticoagulants, such as low-molecular weight heparin, ximelagatran, fondaparinux, and rivaroxaban. Warfarin, a slow-acting oral anticoagulant, raised the risk to a lesser extent.

List of references giving details and results of clinical pathways for joint replacement arthroplasty. Prepared by AAPMR American Academy of Pysical Medicine and Rehabilitation

FLEXION | Newsletter for Orthopedic Surgeons Volume 4 - Number 1 September 1996
Enhanced Instrumentation for Removal of a Bone Plug and Cement in the Distal Canal
Jeffrey M. Hayer, MD Attending Orthopaedic Surgeon Franklin Medical Center Greenfield, Mass

Full Text of JBJS B 81: 3, 495 Replacement of the proximal humerus in 18 children aged between 6 & 12 after bone tumour resection. The prosthesis allowed lengthening which was performed on 11 patients (mean 3 cms)

Review of factors affecting the utility and acceptance of CAOS techniques

Rabin, Graf, Hopkinson & Hallab 2005
Metal hypersensitivity is commonly reported in the literature and can include hypersensitivity related to pacemakers, dental implants, and orthopedic hardware. The development of metal sensitivity after implantation of orthopedic hardware is common.
The clinical significance of metal sensitization remains a question. Nonetheless, the orthopedic surgeon must be aware of the potential problem, and when other more common causes of implant failure have been excluded, the possibility of allergic reaction to the metal must be considered, evaluated, and treated.
Synonyms and related keywords: pacemaker, dental implant, orthopedic implant, implanted orthopedic device, allergic reaction, nickel hypersensitivity, chromium sensitivity, cobalt sensitivity, migration inhibition factor, MIF, lymphocyte transformation testing, LTT proliferation testing, metal hypersensitivity implant hypersensitivity

Archive copy
Implant Wear in Total Joint Replacement: Clinical and Biologic Issues, Material and Design Considerations Edited by Timothy M. Wright, PhD and Stuart B. Goodman, MD, PhD A symposium held in October 2000 Table of Contents Clinical Issues Chapter 1 What is the clinical scope of implant wear in the hip and how has it changed since 1995? Chapter 2 What is the clinical scope of implant wear in the knee and how has it changed since 1995? Chapter 3 What patient-related factors contribute to implant wear? Chapter 4 What surgical-related factors contribute to implant wear? Chapter 5 How should wear-related implant surveillance be carried out and what methods are indicated to diagnose wear-related problems? Chapter 6 What are the systemic consequences of wear debris clinically? Chapter 7 What guidelines/algorithms (both operative and nonoperative) are there for the treatment of osteolysis? Chapter 8 What are the best outcome measures for wear? Chapter 9 What is the outcome of the treatment of osteolysis? Biologic Issues Chapter 10 What are the local and systemic biologic reactions to wear debris? Chapter 11 What are the mediators (cellular, molecular, etc) of the local and systemic biologic reactions to wear debris? Chapter 12 Are there host factors that determine/modulate the biologic response to wear particles? Chapter 13 What specific features of wear particles are most important in determining the adverse biologic reactions? Chapter 14 What is the role of endotoxin and fluid pressure in osteolysis? Chapter 15 What experimental approaches (tissue retrieval, in vivo, in vitro, etc) have been used to investigate the biologic effects of particles? Chapter 16 Are there biologic markers of wear? Chapter 17 What potential biologic treatments are there for osteolysis? Material and Design Considerations Chapter 18 What design and material factors influence wear in total joint replacement? Chapter 19 What is the role of wear testing and joint simulator studies in discriminating among materials and designs? Chapter 20 What design factors influence wear behavior in total knee replacement? Chapter 21 What design factors influence wear behavior at the articulating surfaces in total hip replacement? Chapter 22 What are the wear mechanisms and what controls them? Chapter 23 What material properties and manufacturing procedures influence wear mechanisms? Chapter 24 What modifications can be made to materials to improve wear behavior? Chapter 25 What evidence is there for using alternative bearing materials?

Abstract Journal of Bone and Joint Surgery - British Volume, Vol 88-B, Issue 11, 1487-1491.
Custom-made intercalary endoprostheses may be used for the reconstruction of diaphyseal defects following the resection of bone tumours. The aim of this study was to determine the survival of intercalary endoprostheses with a lap joint design, and to evaluate the clinical results, complications and functional outcome. We retrospectively reviewed six consecutive patients, three of whom underwent limb salvage with intercalary endoprostheses of the tibia, two of the femur, and one of the humerus. Their mean age was 42 years (28 to 64). The mean follow-up was 21.6 months (9 to 58). The humeral prosthesis required revision at 14 months owing to aseptic loosening. There were no implant-related failures. Musculoskeletal Tumour Society functional outcome scores indicated that patients achieved 90% of premorbid function. Custom intercalary endoprostheses result in reconstructions comparable with, if not better than, those of allografts. Using this design of implant reduces the incidence of early complications and difficulties experienced with previous versions.

This patient has a very interesting clinical history. On this occasion, presenting with a pathological fracture secondary to a Pleomorphic rhabdomyosarcoma with a high mitotic rate. This was an extremely aggressive and highly malignant tumour and is the fourth primary tumour for this patient. The surgery was performed at St. Vincent’s private hospital in Sydney. The removal of the tumour, which had infiltrated the soft tissue surrounding the femoral shaft, took many hours. The length of bone removed measured 24 centimeters or 9.5 inches. As can be seen in the gallery below, the ‘osteobridge’ modular diaphyseal prosthesis was used to bridge the gap and restore length. The patient was ambulating on day two post-op. (illustrated)

The Oswestry Outcome Centre is an organisation dedicated to the the collection of clinical data and assessment of major planned operations. Aims are to provide evidence of expertise in the field of major joint arthroplasty. To enable us to plot an individuals progress against a standard survival curve in order to ascertain how well they are doing. To identify problems or benefits of each type of prosthesis.

JBJS B 78; 4; 1022 1996 full text
Custom made endoprostheses were used in 18 patients with median follow-up 65 months. "We conclude that diaphyseal endoprostheses offer a good clinical and functional outcome in the lower limb"

originally Charnley used High Density Polyethylene and later this was changed to Ultrahigh Molecular Wt Polyethylene
- impact strength of UHMWPE is higher than that for HDPE and the density of UHMWPE is much lower than for HDPE;
- UHMWPE has better abrasion resistance, strength, resistance to deformation, and fatigue strength
Wheeless' Textbook of Orthopaedics

Instruments validation Alejandro Allepuz , Mireia Espallargues , Montse Moharra , Merce Comas , Joan MV Pons and Network Research Group on Support Instruments IRYSS BMC Health Services Research 2008, 8:76 Abstract and link to free full text
Prioritisation instruments were developed for patients on waiting list for hip and knee arthroplasties (AI) and cataract surgery (CI). The aim of the study was to assess their convergent and discriminant validity and inter-observer reliability.

Details in Table 1 of this paper