As the population continues to grow and age, the incidence of revision total knee replacement (RTKR) is expected to rise significantly. Modularity within revision total knee systems is common, and recognition of modular junctions as an important source adverse local tissue reaction (ALTR) has not yet been fully described in the literature. In both hips and knees, ALTR may be caused by wear debris from articulating surfaces, stress shielding, and other classic areas of focus, but now attention is shifting towards the role of corrosion products from modular junctions. In severe cases, junctions can become welded together creating significant hurdles in revisions and potentially altered biomechanics in vivo. In view of these issues, the present study was undertaken: (i) to examine the level of damage observed in modular junctions of total knee prostheses obtained at revision, (ii) to correlate the severity of surface damage to the design and composition of the mating components, and (iii) to associate patient demographics and comorbidities with the spectrum of corrosion and fretting seen in retrieved implants. 117 TKR components from 76 patients were examined after retrieval from revision procedures performed at a single institution. Patient demographics and clinical data were compiled. The retrievals consisted of 57 femoral components and 60 tibial components from a diverse range of manufacturers. The implants were disassembled manually, or in a mechanical testing machine if cold welded, and separated into groups based on mating material type. Modular junctions were then examined using stereomicroscopy (Wild) at magnifications of X6 to X31. Upon inspection, damage on the male component was graded using modified Goldberg scales for corrosion and fretting (Table 1). Factors associated with trunnions having damage scores of 3 or higher were evaluated using standard statistical procedures to determine the susceptibility for corrosion of each junction type and location.Introduction
Methods
Corrosion products from modular taper junctions of hip prostheses have been implicated in adverse local tissue reactions after THR. Numerous factors have been proposed as the root causes of this phenomenon, including implant design and materials, manufacturing variables, intraoperative assembly, and patient lifestyle. As significant taper damage only occurs in a few percent of cases of THR, we have addressed this complication using a “forensic” examination of retrieval specimens to gain insight into the factors initiating the cascade leading to irreversible damage of the modular interface. In this study we report the categorization of over 380 retrievals into groups having shared damage patterns, metallic composition, and interface surface geometries to isolate the genesis of mechanically-assisted corrosion and its relation to intraoperative assembly, manufacturing, and postoperative loading. A total of 384 femoral components were examined after retrieval at revision THR. The implants were produced by a diverse range of manufacturers, 271 in CoCr, and 113 in TiAlV, with both smooth (253) and machined (131) tapers. Initially, the implants were sorted into groups based on composition and taper roughness. Each trunnion was then cleaned to remove organic deposits and examined by stereomicroscopy at X6-X31. After an initial pilot study, we developed a classification system consisting of 8 basic patterns of damage (Table 1). We then classified all 384 trunnions according to this 8-group system. The prevalence of each pattern was calculated on the basis of both composition and surface texture of the trunnion.Introduction
Methods
With the rising demand for primary total hip arthroplasty (THA), there has been an emphasis on reducing the revision burden and improving patient outcomes. Although studies have shown that primary THA effectively minimizes pain and restores normal hip function for activities of daily living, many younger patients want to participate in more demanding activities after their operation. With IRB approval, 2 groups of subjects were enrolled in this study: (i) 143 patients at an average of 25 months (range 10–69 months) post-primary THA, and (ii) 165 control subjects with no history of hip surgery or hip pathology. All subjects were assigned to one of four categories according to their age and gender: Group A: 40–60 year old males (31 THA; 42 Controls), Group B: 40–60 year old females (25 THA; 53 Controls), Group C: 60–80 year old males (35 THA; 25 Controls), and Group D: 60–80 year old females (36 THA; 23 Controls). Each patient completed a self-administered Hip Function Questionnaire (HFQ) which assessed each subject's satisfaction, expectations, symptoms and ability to perform a series of 94 exercise, recreational and daily living activities. These included participation in work-out activities, adventure and water sports, running and biking, and contact and team sports. Each participant was also asked their activity frequency, symptom prevalence and satisfaction with their hip in performing each activity.Background
Methods
