Patellofemoral evaluation with radiographs and computed tomography scans in 60 knees of asymptomatic subjects.

PURPOSE: The objectives of this study were to show the results of patellofemoral joint imaging in healthy volunteers, to propose a standardization of the technique, and to test the statistical correlation and reliability of the different imaging results. METHODS: In 30 healthy police academy student volunteers of both sexes, standard knee radiographs and computed tomography (CT) scans were obtained. The angles and distances were measured, and a statistical analysis was applied. The results are presented as mean +/- 2 SDs throughout. RESULTS: The mean Laurin lateral patellofemoral angle on radiographs was 16.4 degrees +/- 8.7 degrees. The mean Insall-Salvati and Caton-Deschamps indexes were 1.09 +/- 0.24 and 0.95 +/- 0.29, respectively. The CT scan values for tilt were determined for the lateral patellofemoral angle by use of both facets (-8.1 degrees +/- 9.8 degrees), the Laurin lateral patellofemoral angle (8.1 degrees +/- 14.5 degrees), the condyle-patellar angle with the lateral facet (14.5 degrees +/- 14 degrees), and the patella major axis (-11.1 degrees +/- 10.6 degrees). The sulcus angle, congruence angle (Merchant angle), and condyle-lateral angle were also obtained on CT scans, with mean values of 139.7 degrees +/- 20.4 degrees , 5.15 degrees +/- 32.6 degrees , and 22.1 degrees +/- 9 degrees , respectively. The tibiofemoral rotation was assessed with the indexes for the distance between the trochlear groove and anterior tibial tuberosity and the distance between the posterior femoral dome and anterior tibial tuberosity. The values for these two indexes were 13.6 +/- 8.8 mm and 17.8 +/- 9.2 mm, respectively. Some parameters showed sex differences. CONCLUSIONS: There are good statistical correlations between some of the tilt values on the radiographs and CT scans, indicating that they move together. The values on the CT scans show good reliability. The CT scans and radiographs are good tests by which to evaluate and quantify patellar alignment. LEVEL OF EVIDENCE: Level I, testing of previously developed diagnostic criteria.

Mid-term results of an AGC total knee arthroplasty system survival and function analysis: 2- to 8-year follow-up results.

Between 1993 and 1999, 148 total knee arthroplasties were performed in Dipreca Hospital; 94 were anatomically graduated components (AGC) cam-and-groove posterior-stabilized total knee arthroplasties. All patients underwent implantation with a cemented posterior cruciate-substituting design, with resurfacing of 3 components. Mean age at surgery was 69 years, and patients were followed up for a minimum of 2 years (range, 2-8). The survival analysis at 8 years was 96.6%. Revision for any reason was considered to be the endpoint. Of patients, 3.2% were lost to follow-up. The mean knee pain and function scores were 89 and 64 of 100, respectively. The scores were also analyzed by categories. This knee arthroplasty follow-up analysis shows excellent midterm results.

The effect of femoral component rotation and asymmetry in total knee replacements.

Between April 1999 and February 2000, femoral component rotation and asymmetry (universal versus anatomic) were studied in a prospective randomized control trial in 101 consecutive patients undergoing total knee replacement. Patients were randomly assigned to four groups. The same surgical technique was used in all patients except for femoral component symmetry and rotational alignment. Universal femoral components provide a cheaper and equally reliable solution compared to anatomic compo nents. External rotation of the femoral component or using an anatomic femoral component did not statistically reduce the need for lateral release or improve patellar tracking.

Ten to fourteen year survival and functional analysis of the AGC total knee replacement system.

A study of 562 Anatomic Graduated Component (AGC) total knee arthroplasties that were performed in 402 patients between November 1986 and September 1990 is reported. All patients had implantation with a cemented posterior cruciate-retaining design, with resurfacing of the patella using all polyethylene patella components. Mean age at surgery was 71 years (range 41-92 years). Patients were followed for a minimum of 10 years (range 10-14 years). Nine knees were lost to follow-up (1.4%). The mean Knee Society Score for pain and function were analyzed by Charnley categories: Category A -- 97 (pain) and 89 (function); Category B -- 91 (pain) and 84 (function); and Category C -- 89 (pain) and 62 (function). The survival analysis at 14 years was 97% with revision for any reason as the endpoint and the authors continue to utilize this implant system.

Results of simultaneous bilateral total knee replacement: a study of 1208 knees in 604 patients.

Bilateral symptomatic knee arthritis is a common clinical problem. There are conflicting opinions as to the advisability of simultaneous sequential bilateral total knee replacement. Complication rates of primary unilateral knee replacement are well documented and there are several small series that compare the two techniques. The objective of this study was to identify the complication rate of simultaneous sequential bilateral total knee replacement in a large patient population. Over a 13-year period, 604 primary bilateral sequential simultaneous total knee replacements (1208 knees) were performed. Office notes and hospital charts were retrospectively reviewed to obtain age, sex, diagnosis, knee alignment, associated comorbidities, operative protocol, transfusions, and complications. The study results showed 5.1% local and 15.3% systemic complications and 0.7% mortality rate (none in the past 9 years). With appropriate patient selection and operative technique, patients who present with bilateral symptomatic knee arthritis can enjoy the benefits of simultaneous sequential bilateral total knee replacement without increasing their risks of complications.