Skyline patellofemoral radiographs can only exclude late stage degenerative changes.
ABSTRACT Accurate preoperative assessment of the patellofemoral joint is especially important in compartment specific knee arthritis. This study aims to show the actual intraoperative grade of patellofemoral cartilage damage that may be reliably detected or excluded by preoperative standard radiographic views. 100 consecutive knees awaiting arthroplasty underwent preoperative lateral and skyline radiographs and were scored using the Ahlback score. Intraoperative cartilage damage was assessed using the Collins score. The sensitivity and specificity were calculated for each grade of cartilage damage. Preoperative anterior knee pain and function were assessed and correlated to the degree of cartilage damage. The lateral radiograph shows poor sensitivity for all grades of disease (0.05-0.23). The skyline shows good sensitivity for grade 4 (large full thickness) damage (0.90) but decreases substantially for grades 1-3 (0.19-0.46). Significantly more people with skyline radiograph joint space narrowing complained of anterior knee pain than those with a normal radiograph (p<0.001). There was only a poor correlation between preoperative anterior pain and intraoperative patellofemoral cartilage damage (r=0.24). The lateral radiograph cannot exclude even large areas of full thickness cartilage damage whereas a normal skyline radiograph can reliably exclude significant (grade 4) patellofemoral disease and should be used in addition to the lateral view.
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ABSTRACT: Patellofemoral joint degeneration is often considered a contraindication to medial unicompartmental knee replacement. We examined the validity of this preconception using information gathered prospectively on the intra-operative status of the patellofemoral joint in 824 knees in 793 consecutive patients who underwent Oxford unicondylar knee replacement for anteromedial osteoarthritis. All operations were performed between January 1998 and September 2005. A five-point grading system classified degeneration of the patellofemoral joint from none to full-thickness cartilage loss. A subclassification of the presence or absence of any full-thickness cartilage loss was subsequently performed to test selected hypotheses. Outcome was evaluated independently by physiotherapists using the Oxford and the American Knee Society Scores with a minimum follow-up of one year. Full-thickness cartilage loss on the trochlear surface was observed in 100 of 785 knees (13%), on the medial facet of the patella in 69 of 782 knees (9%) and on the lateral facet in 29 of 784 knees (4%). Full-thickness cartilage loss at any location was seen in 128 knees (16%) and did not produce a significantly worse outcome than those with a normal or near-normal joint surface. The severity of the degeneration at any of the intra-articular locations also had no influence on outcome. We concluded that, provided there is not bone loss and grooving of the lateral facet, damage to the articular cartilage of the patellofemoral joint to the extent of full-thickness cartilage loss is not a contraindication to the Oxford mobile-bearing unicompartmental knee replacement.Journal of Bone and Joint Surgery - British Volume 01/2008; 89(12):1597-601. · 2.69 Impact Factor
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ABSTRACT: To correlate radiographic findings of osteoarthritis on axial knee radiographs with arthroscopic findings of articular cartilage degeneration within the patellofemoral joint in patients with chronic knee pain. The study group consisted of 104 patients with osteoarthritis of the patellofemoral joint and 30 patients of similar age with no osteoarthritis of the patellofemoral joint. All patients in the study group had an axial radiograph of the knee performed prior to arthroscopic knee surgery. At the time of arthroscopy, each articular surface of the patellofemoral joint was graded using the Noyes classification system. Two radiologists retrospectively reviewed the knee radiographs to determine the presence of marginal osteophytes, joint-space narrowing, subchondral sclerosis, and subchondral cysts. The sensitivity and specificity of the various radiographic features of osteoarthritis for the detection of articular cartilage degeneration within the patellofemoral joint were determined. The sensitivity of marginal osteophytes, joint-space narrowing, subchondral sclerosis, and subchondral cysts for the detection of articular cartilage degeneration within the patellofemoral joint was 73%, 37%, 4%, and 0% respectively. The specificity of marginal osteophytes, joint-space narrowing, subchondral sclerosis, and subchondral cysts for the detection of articular cartilage degeneration within the patellofemoral joint was 67%, 90%, 100%, and 100% respectively. Marginal osteophytes were the most sensitive radiographic feature for the detection of articular cartilage degeneration within the patellofemoral joint. Joint-space narrowing, subchondral sclerosis, and subchondral cysts were insensitive radiographic features of osteoarthritis, and rarely occurred in the absence of associated osteophyte formation.Skeletal Radiology 01/2007; 35(12):895-902. · 1.74 Impact Factor
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ABSTRACT: Over the past decade, there has been an increase in the number of revision total hip and knee arthroplasties performed in the United States. The purpose of this study was to formulate projections for the number of primary and revision total hip and knee arthroplasties that will be performed in the United States through 2030. The Nationwide Inpatient Sample (1990 to 2003) was used in conjunction with United States Census Bureau data to quantify primary and revision arthroplasty rates as a function of age, gender, race and/or ethnicity, and census region. Projections were performed with use of Poisson regression on historical procedure rates in combination with population projections from 2005 to 2030. By 2030, the demand for primary total hip arthroplasties is estimated to grow by 174% to 572,000. The demand for primary total knee arthroplasties is projected to grow by 673% to 3.48 million procedures. The demand for hip revision procedures is projected to double by the year 2026, while the demand for knee revisions is expected to double by 2015. Although hip revisions are currently more frequently performed than knee revisions, the demand for knee revisions is expected to surpass the demand for hip revisions after 2007. Overall, total hip and total knee revisions are projected to grow by 137% and 601%, respectively, between 2005 and 2030. These large projected increases in demand for total hip and knee arthroplasties provide a quantitative basis for future policy decisions related to the numbers of orthopaedic surgeons needed to perform these procedures and the deployment of appropriate resources to serve this need.The Journal of Bone and Joint Surgery 04/2007; 89(4):780-5. · 3.23 Impact Factor