Subsidence of Tibial Components in Knee Arthroplasty
ABSTRACT To assess the ability of conventional radiography to identify subsidence of tibial components.
Forty-three cases of knee arthroplasty were followed for 4 years using roentgen stereophotogrammetric analysis as the gold standard.
Roentgen stereophotogrammetric analysis showed subsidence in all uncemented prostheses, whereas two thirds of the cemented prostheses subsided. Medially, the sensitivity of conventional radiography was low, 25%, whereas the specificity was 83%. For the other regions, the sensitivity was almost 100%, although the specificity was as low as 66% frontally and dorsally.
Medially, where most prostheses were inserted with a slight overhang, conventional radiography identified subsidence correctly. Laterally, frontally, and dorsally, however, conventional radiography overestimated the subsidence by a factor of 2 to 3. This error was caused by bony protrusions arising in the cranial direction from the uncovered bone surfaces, thus changing the points of reference. This problem arose more commonly in uncemented cases, whereas cement seemed to seal the bone.
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ABSTRACT: 40 patients with non-inflammatory arthrosis and minor preoperative deformity (< or =5 degrees ) were operated on with an AMK type (DePuy, Johnson & Johnson) total knee arthroplasty (TKA). The posterior cruciate ligament was retained. The patients were divided into those with a flat (terminology of the manufacturer: standard) or a concave (terminology of the manufacturer: constrained) polyethylene insert (20 in each group). Radiostereometric (RSA) examinations were done postoperatively and after 3,12 and 24 months. The median absolute rotations of the tibial inserts varied between 0.12 and 0.24 (range 0.00-1.54) degrees, with no differences between the 2 groups. The median maximum total-point motions (flat/concave = 0.41/0.42 mm), the maximum subsidence or lift-off did not differ. The Hospital for Special Surgery knee score and the patients' opinion about the operation, based on their preoperative expectations, showed little, if any, differences. At 2 years, 10 of 20 patients with flat and 13 of 19 with concave inserts regarded their knee function as normal or almost so.Acta Orthopaedica Scandinavica 07/2001; 72(3):257-65. DOI:10.1080/00016470152846583
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ABSTRACT: Human physical activity is influenced in a variety of ways by physiological conditions and psychomotor response. Joints are essential parts of the musculoskeletal system, connecting the skeletal structure and enabling the muscles to actuate physical activity. Pain, subluxation and arthritis are common joint pathologies associated with disability. Biomechanical studies augment our understanding of normal joint function and the etiology of joint disorders, and provide treatments for the restoration of joint function.
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ABSTRACT: We report prospective clinical and radiographic outcomes of a series of 219 hydroxyapatite-coated Duracon (Stryker Howmedica Osteonics Corporation, Kalamazoo, Mich) total knee arthroplasties with a follow-up of 5 to 8 years. Knee Society Score, Western Ontario and McMaster Universities Osteoarthritis index (WOMAC), and SF-12 Health Status Questionnaire were used. Analysis of fluoroscopic radiographs was performed with the American Knee Society Score. All living patients (186 knees) were followed up. Twenty-eight patients (30 knees) had died. The preoperative Knee Society Score of 43.8 increased to 77.1 and the preoperative Function score of 20.3 increased to 63.4. WOMAC scores showed marked improvement (pain, 250 preoperatively to 157; stiffness, 115 preoperatively to 56; and function, 910 preoperatively to 588). There was no radiographic evidence of loosening or migration. Gaps visible at the bone-implant interface healed over the first year. Three prostheses were revised, 2 for deep infection and 1 for tibial tray subsidence. A survivorship of 98.6% has been achieved at 8 years. This intermediate-term study with 100% follow-up at 8 years demonstrates excellent clinical and radiographic outcomes. It is our opinion that these are comparable to the gold standard cemented total knee arthroplasties and may have advantages over other uncoated cementless designs.The Journal of arthroplasty 02/2008; 23(5):677-82. DOI:10.1016/j.arth.2007.06.002 · 2.67 Impact Factor