Objectives : To determine the change in passive knee kinematics after Oxford Unicompartment Arthoplasty (UKA) (Biomet, Uk); and to compare the change in kinematics post-operatively between image guided and the normal surgical procedure.

Background: In anteromedial osteoarthritis, only the medial compartment of the knee is affected and the collateral ligaments as well as the cruciate mechanism are intact. These preconditions make the knee suitable for UKA. The operative technique of the Oxford UKA theoretically allows the surge on to replicate the natural kinematics of the knee, due to accurate ligament balancing and fully congruent meniscal bearing design of the prosthesis. Our hypothesis was that no difference in tibiofemoral kinematics is observed after UKA. In addition we also hypothesised that the results of the image guided surgery would be the same as the normal surgical procedure.

Design/Methods: To test this hypothesis, we conducted a study using 13 normal human cadaveric knees. For kinematic analysis, the Surgetics TM surgical navigation system (Praxim, France), equipped with custom written tracking software, was used. Reference markers were mounted to the proximal tibia and the distal femur. In a standardized set-up, the knee was positioned in a leg holder and preoperative kinematics of the normal knee was recorded after a para-patellar mini-incision (70–90 mm). Joint kinematics were recorded during passive knee flexion and plotted against flexion angle. Oxford UKA was performed; the standard Phase III instrumentation was used for six knees and the image guided procedure was used for seven knees. The main difference between the standard and image guided procedures was that the inter-medullary rod was not used for the image guided surgery. After the operation postoperative kinematics were recorded using the same measurement protocol. All data were processed using Matlab 6.1 analysis software (The Math Works Inc., MA, USA). Preoperative and postoperative tibiofemoral kinematics were determined and compared. The mechanical axes of the tibia and femur were determined and kinematics represented as functions of knee flexion range. Over both the flexing and extending cycles of the knee the changes in tibiofemoral rotation (& #916;ROT), tibiofemoral ab/adduction (& #916;ABD), and distances between the origins of the mechanical axes (& #916;X, & #916;Y, & #916;Z) were calculated between pre and post-operative states.

Design/Methods: To test this hypothesis, we conducted a study using 13 normal human cadaveric knees. For kinematic analysis, the Surgetics TM surgical navigation system (Praxim, France), equipped with custom written tracking software, was used. Reference markers were mounted to the proximal tibia and the distal femur. In a standardized set-up, the knee was positioned in a leg holder and preoperative kinematics of the normal knee was recorded after a para-patellar mini-incision (70–90 mm). Joint kinematics were recorded during passive knee flexion and plotted against flexion angle. Oxford UKA was performed; the standard Phase III instrumentation was used for six knees and the image guided procedure was used for seven knees. The main difference between the standard and image guided procedures was that the inter-medullary rod was not used for the image guided surgery. After the operation postoperative kinematics were recorded using the same measurement protocol. All data were processed using Matlab 6.1 analysis software (The Math Works Inc., MA, USA). Preoperative and postoperative tibiofemoral kinematics were determined and compared. The mechanical axes of the tibia and femur were determined and kinematics represented as functions of knee flexion range. Over both the flexing and extending cycles of the knee the changes in tibiofemoral rotation (& #916;ROT), tibiofemoral ab/adduction (& #916;ABD), and distances between the origins of the mechanical axes (& #916;X, & #916;Y, & #916;Z) were calculated between pre and post-operative states.

Conclusions: The image guidance system used in our study is a valuable tool for assessing pre- and postoperative knee kinematics. Oxford Unicompartmental Knee Arthroplasty with the Phase III instrumentation in the presence of the cruciate mechanism reproduces the normal kinematics of the knee very accurately. The image guided procedure, performed without the inter-medullary rod, produced similar results to the standard surgery. Image guidance has a great potential for the assessment of pre- and post-replacement kinematics of the knee joint during surgery.

Aims: We report the clinical and radiologic outcome after cemented PFC®- TKA at mean follow-up of 9,1 years. Methods: Consecutively all patients with PFC®-TKA between 1989–1993 were investigated. Implant survival was estimated using the method of Kaplan-Meier. Radiologic evaluation was done using the criteria of the American Knee Society. Knee and Function Score of the American Knee Society were used to assess clinical outcome. Hannover Functional Ability Questionaire for Osteoarthritis (FFbH-O) measured limitations in activities of daily living. Visual analogue scale divided pain sensation and a 6-graded scale estimated patient satisfaction. Results: 140 TKA were performed on 122 patients (female:male ratio 3:1, average age 67 years, BMI 27,5). Follow-up rate was 100%. 5-year and 10-year survival was 97% and 92,7%. Radiologic measurements, diagnosis and BMI did not influence survival rate. Clinical results revealed 83 points for knee and 50 points for function score. 88% had a decreased FFbH-O. 57% had no and 33% slight-moderate pain. 72% were extremely or very satisfied. Patient satisfaction correlated well with the knee score, but poorly with the function score. Primary diagnosis (OA/RA) did not influence outcome. Conclusion: PFC®-TKA showed very good survival rates at 5 and 10 years. Knee score was mainly excellent-good, but function score was poor, mainly due to high patient age and associated diseases. Radiologic alignment did not influence outcome.

Rheumatoid Arthritis (RA) is the most frequent inflammatory rheumatic disease. At the beginning of the disease, where after today‘s knowledge the therapeutic possibilities are largest, the diagnostic methods do not permit a differentiated estimation of the prognosis. Conventional x-rays are mostly normal and serum markers unspecific. So far – in contrast to other diseases – only few information has been drawn from the pathomorphologic substrate “synovium” itself to assess the prognosis. Reasons therefore are found in difficulties in obtaining synovial tissue without surgical intervention, particularly in patients with early arthritis.

By minimalizing the diagnostic instruments and improvement of the technique, nowadays synovial tissue sampling in RA has become minimal invasive and even possible from smallest joints, such as finger joints. Hereby, synovial analysis is open for detecting pathways of inflammation and joint destruction, which might support the advancement of new therapeutic strategies, followed by a better prognosis and outcome of RA.