Joseph Schatzker

Ceramic head failure

A case of abrupt failure of the ceramic head component of a total hip arthroplasty is reported. The prosthesis had been inserted more than 5 years previously and had functioned well until its abrupt failure. At revision, the metal femoral and acetabular components were intact and well fixed. The broken ceramic head was replaced with a metal component, and the polyethylene liner replaced with a new one.

Non-union of the odontoid process. An experimental investigation.

A clinical study of fractures of the odontoid process showed a 62 per cent failure on union. Of many features studied, only displacement and its direction had a definite bearing on non-union of the fracture. Blood supply was considered as a possible etiological factor. The blood supply of the human odontoid was elucidated by means of studying 19 human autopsies by means of microangiography. The dog was found to have a similar blood supply and hence, was used as the experimental model. Two osteotomies were performed; one below the accessory ligaments and one above the accessory ligaments. All osteotomies carried out below the accessory ligament united and all carried out above failed to unite. Microangiographic studies revealed however, that avascular necrosis was not the cause of non-union. Further anatomic studies revealed that different size gaps occurred depending on the level of the osteotomy, with a large gap occurring in the osteotomy of the odontoid which was performed above the accessory ligament. First the result of immobilization and the healing of the odontoid osteotomy was derived, by carrying out an instant occipito-cervical fusion by means of wire loops and methylmethacrylate. In distinction to the free floating apical segment of non-immobolized spines, with a high odontoid osteotomy, the occipito-cervical fusion resulted in a dense fibrous tissue stabilizing the apical fragment but at no time was bony union observed. A final attempt was to secure immobilization and reduce the gap, by carrying out only a partial osteotomy. The osteotomy was performed in such a way that the posterior cortex was left intact. Union occurred in all instances. The fracture gap and movement play a definite role in the pathogenesis of pseudarthrosis of the odontoid process. Where gap and movement were eliminated, union occurred. It is difficult to transpose this experimental situation to the clinical one, for the assessment of gap clinically, is only radiographic. This method is much too imprecise to be of value in this assessment. The fact however, that a high rate of non-union is associated with a high degree of displacement, supports the experimental thesis.

Changes in the AO/ASIF principles and methods

Abstract Early AO/ASIF principles and methods emphasized the operative treatment of fractures, the mechanical aspects of internal fixation and the absolute stability of all fragments. Absolute stability was thought necessary to make internal fixation sufficiently strong to allow immediate movement of joints and partial loading of the bones. Investigation revealed that osteoporosis or accelerated Haversian remodelling associated with plating was not the result of stress protection but the result of damage to the blood supply to the bone. Similarly accelerated Haversian remodelling was noted along the endosteum of long bones with intramedullary nailing. This remodelling paralleled the distribution of dead bone brought about by reaming and nailing. Primary bone healing is histologically identical to remodelling and would be more appropriately regarded as accelerated remodelling of the dead bone at the fracture under conditions of absolute stability. Under conditions of relative stability only living bone will unite because only living bone is capable of overcoming motion and bringing about stability by the formation of callus. The recognition that implants and the manipulation of fragments devitalize bone and can interfere with union has brought about a shift from the quest for absolute stability to the emphasis on the preservation of the blood supply and to the recognition of the biological requirements of the different segments of bone. Thus, fractures involving end segments, such as articular fractures, require anatomical reduction and absolute stability for union and regeneration of articular cartilage, whereas diaphyseal fractures require only relative stability with restoration of length, axial alignment, and rotation for union and for the full return of function. Thus, diaphyseal fractures of long bones are best treated with locked intramedullary nailing whereas end segment fractures require lag screw fixation and plating. Fractures of the forearm are an exception. The anatomical relationship of the two bones makes them behave as a .joint. Therefore, they require an anatomical reduction for full return of function. Where intramedullary nailing is contraindicated methods of indirect reduction and bridge plating have been developed to minimize devitalization of bone. The recent recognition that manipulations of the medullary canal such as reaming and nailing may seriously compromise pulmonary function has led to a reappraisal of the intramedullary nailing of long bone fractures in polytrauma patients with pulmonary contusion and a high ISS. Therefore, there are a large number of specific indications for absolute stability and plating, and consequently a great need to develop new plates and new methods of their application which would minimize the damage to the blood supply to the bone and promote union.

Economic evaluations in the hip arthroplasty literature: Lessons to be learned

Readers are increasingly encountering articles dealing with health economic evaluations that compare various surgical strategies, leaving orthopaedists with the challenge of determining which program is cost-efficient and truly pertains to their setting. This study carries out a systematic review of the literature to appraise the quality, quantity, and type of economic evaluation as it pertains to the hip arthroplasty literature. To identify all relevant articles, we conducted a comprehensive computerized bibliographic search of Medline from 1966 to 1996. This search produced 1,611 abstracts that were screened. Studies that were incorporated met the following inclusion criteria: i) formal economic analysis, ii) an intervention specific to hip arthroplasty, and iii) the perspective of the study was evident (ie, patient, provider, society). These studies were appraised with regards to methodologic soundness based on 8 established economic principles. Only 68 articles from the 138 retrieved met the study criteria. Only 2 of the 68 articles met all 8 criteria of a comprehensive economic evaluation. The hip arthroplasty literature is deficient in methodologically sound economic evaluations. Several guidelines are introduced to aid orthopaedists in appraising the various economic studies, and recommendations are made to improve the quality of these studies in the orthopaedic literature. We suggest that the generation of such information should rank high on the priority list of the orthopaedic profession, granting agencies, and governments.

Extended Anterolateral Approach for Complex Lateral Tibial Plateau Fractures

Abstract Complex fractures of the lateral tibial plateau may extend to the posterior rim of the knee and to the tibial spines. Displaced fractures of the posterolateral corner of the tibial plateau may result in joint incongruity and instability, especially with the knee in flexion. Anatomical reduction of the joint surface and containment of the tibial rim are the primary goals of the treatment in such cases. Dedicated surgical approaches including dissection of the peroneal nerve, sometimes in association with an osteotomy of the fibular head are typically used to address these injuries. Some techniques require special positioning of the patient on the operative table. Anatomical studies of the knee allowed us to conclude that an osteotomy of the lateral epicondyle of the femur may be a natural extension of the standard anterolateral approach to the tibial plateau. The main advantage of this approach is the broad exposure of the lateral joint surface, allowing its anatomical reduction. It does not violate the proximal tibiofibular joint or pose a risk to the peroneal nerve. The main limitation is the lack of visualization of the posterior metaphysis of the tibia, preventing the application of a buttress plate parallel to the plane of fracture split. To overcome this limitation, we describe a method to support the posterior tibial plateau rim, in cases of bicondylar tibial plateau fractures, combining the extended anterolateral with the posteromedial approach. For selected cases, with a significant compromise of the posterolateral and anterolateral quadrants of the tibial plateau, including the tibial spines, the extended anterolateral approach may be complemented by a planned detachment of the anterior horn of the lateral meniscus. In such variant, a complete exposure of the entire surface of the lateral tibial plateau and tibial spines is achievable, assuring optimal conditions for an anatomical reduction of the articular surface.

The Impact of Computed Tomography on Decision Making in Tibial Plateau Fractures

&NA; Schatzker introduced one of the most used classification systems for tibial plateau fractures, based on plain radiographs. Computed tomography brought to attention the importance of coronal plane‐oriented fractures. The goal of our study was to determine if the addition of computed tomography would affect the decision making of surgeons who usually use the Schatzker classification to assess tibial plateau fractures. Image studies of 70 patients who sustained tibial plateau fractures were uploaded to a dedicated homepage. Every patient was linked to a folder which contained two radiographic projections (anteroposterior and lateral), three interactive videos of computed tomography (axial, sagittal, and coronal), and eight pictures depicting tridimensional reconstructions of the tibial plateau. Ten attending orthopaedic surgeons, who were blinded to the cases, were granted access to the homepage and assessed each set of images in two different rounds, separated to each other by an interval of 2 weeks. Each case was evaluated in three steps, where surgeons had access, respectively to radiographs, two‐dimensional videos of computed tomography, and three‐dimensional reconstruction images. After every step, surgeons were asked to present how would they classify the case using the Schatzker system and which surgical approaches would be appropriate. We evaluated the inter‐ and intraobserver reliability of the Schatzker classification using the Kappa concordance coefficient, as well as the impact of computed tomography in the decision making regarding the surgical approach for each case, by using the chi‐square test and likelihood ratio. The interobserver concordance kappa coefficients after each assessment step were, respectively, 0.58, 0.62, and 0.64. For the intraobserver analysis, the coefficients were, respectively, 0.76, 0.75, and 0.78. Computed tomography changed the surgical approach selection for the types II, V, and VI of Schatzker (p < 0.01). The addition of computed tomography scans to plain radiographs improved the interobserver reliability of Schatzker classification. Computed tomography had a statistically significant impact in the selection of surgical approaches for the lateral tibial plateau.

Corrective Intra-articular Osteotomies for Tibial Plateau Malunion

&NA; Anatomical reduction of the articular surface, restoration of mechanical axis, and containment of articular rim are the goals of the treatment of tibial plateau fractures, with an ultimate aim to restore joint congruity and stability. Tibial plateau malunions or nonunions are a result of a failed treatment. This article aims to review the most typical failure models and some strategies to overcome them by using joint preservation surgical techniques.