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George Papachristou

Publications and source records attributed to George Papachristou.

6 recordsLinked to original sources
PubMed2006

ACL reconstruction and the implication of its tibial attachment for stability of the joint: anthropometric and biomechanical study.

The planar topography of the anterior cruciate ligament (ACL) insertion was investigated and correlated to the use of the double-bundle/double tibial tunnel ACL reconstruction technique within the ACL tibial insertion area. The anteroposterior and mediolateral length of the tibial ACL attachment and the distances of the tibial insertion area from the anterior and posterior tibial borders were measured and the stability of the joint was tested using the double-bundle/double tibial tunnel ACL reconstruction technique. The anteroposterior length, 19.54 mm in men and 17.36 mm in women, of the ACL insertion, averaged approximately 40% of the total intercondylar anteroposterior dimension of the plateau. This broad distribution of insertion fibres ensures ligament tension and hence joint stability. The reported anteroposterior broad insertion of ACL fibres to the tibia is not sufficiently reproduced by the use of one or more bundles having a common tibial tunnel for the ACL reconstruction. In our view, this might be better achieved with two different bundles, with separate tunnels, and independent tensioning in different knee angles. This technique might achieve better results in human knee stability as opposed to other reported techniques.

Aged↗
PubMed2006

Cementless LCS rotating-platform knee arthroplasty in patients over 60 years without patella replacement: a mid-term clinical-outcome study.

BACKGROUND: The aim of this prospective paper is to present the results of a cementless LCS rotating-platform artificial knee design without resurfacing of the patella in patients over 60 years of age. MATERIAL/METHODS: In this prospective series, 234 patients were included with 251 knees. The LCS rotating-platform uncemented design was used in all cases, without replacement of the patella. Thirty-four patients were men and 200 were women. Two hundred three patients were suffering from osteoarthrosis (10 bilateral) and 31 patients (7 bilateral) from rheumatoid arthritis. Seventeen patients had a bilateral procedure. Prophylactic antibiotics and anticoagulants were also instituted to all patients. RESULTS: Forty-nine patients developed deep vein thrombosis and responded well to the applied conservative treatment. Overall results in the first 251 cementless cases at 2 to 9.8 years' follow-up (average: 5.7 years) were good to excellent in 94.4%, fair in 4.7%, and poor in 0.7%. Radiographs of the knees showed good bonding and no signs of radiolucency. The average clinical and functional Knee Society Ratings were 21.07 points and 30.95 points, respectively, preoperatively and 87.95 points and 78.56 points, respectively, at the final follow-up evaluation. CONCLUSIONS: With an average follow-up of 5.7 years, uncemented LCS rotating-platform knee joint arthroplasty without replacing the patella in patients over 60 years old was found to perform well, with encouraging clinical and radiological results and a survival rate of 98.1%.

Aged↗
PubMed2004

Photoelastic study of the internal and contact stresses on the knee joint before and after osteotomy.

INTRODUCTION: The treatment of knee osteoarthrosis represents a difficult task. Osteotomy is one of the treatment regimes which, in earlier times, was the only surgical procedure giving reliable mid-term results. The improvement was attributed either to the changing of the acting forces or to the so-called biological factor. The use of a photoelastic model allows the observation of the direction of the significant contact and internal stresses at every point in a single plane. MATERIALS AND METHODS: In the present study, we investigated the stress-strain situation of the knee joints in models made from 1 cm thick Araldite plates. These models reproduce tracings from anteroposterior X-ray views of monopodal loading of human knee joints. The models represent: normal knee joints, normal varus or valgus knee joint, knee joints suffering osteoarthrosis in varus or valgus, and knee joints suffering osteoarthrosis, following corrective osteotomies. The models were first loaded along the longitudinal axis with the leg in full extension, with 70 kg (body weight) and then with 140 kg, representing double the normal body weight. RESULTS: The application of longitudinal force on a normal knee joint, in full extension, results in symmetrical arrangement of trajectories in the condyles. Loading of the leg in varus or valgus produces shifting of stresses towards the inclination side. Increased contact stresses are always greater in the tibial condyles. The concentration of strain is directed towards the cortices of the loaded area. In a knee joint with osteoarthrosis, deviation of the trajectories in the condyles towards the inclination of the leg axis is observed. Also, increased contact stresses appear in the articular surfaces, on the inclination side. Isoclinics have meeting points on the loaded cortices. Supracondylar femoral osteotomy, or high tibial osteotomy, restores the axis of the leg, redistributes internal stresses (strain) in the condyles, corrects the trajectorial lines, and redistributes contact stresses in the articular surfaces towards the normal values. CONCLUSION: Correction of the femorotibial axis results in redistribution of the isochromatics, isoclinics, trajectorial lines and contact stresses. The values of the above parameters are corrected and remain closer to these of the normal knee, but in no case does the correction of all the above factors attain normal values. The change of direction of the main stresses following osteotomies towards those of the normal knee probably represents the biomechanical explanation of the way the osteotomy relieves pain and improves function.

Biomechanical Phenomena↗
PubMed2003

Isolated meniscal repair in the avascular area.

The authors present the results of a prospective cohort study carried out in young patients, to evaluate the outcome of meniscal repair in the avascular region of the meniscus. Forty five patients underwent either open (23 patients) or arthroscopic repair (22 patients) between 1982 and 1992. Seventeen men and eight women were included in the present study; their ages at the time of admission ranged from 16 to 27 years. They all presented with isolated longitudinal tears in the central avascular region of the meniscus. No patient with any kind of concomitant lesion was included in this series. The stitches were usually passed through the injured area and the synovium, and the knots were tightened outside the capsule. Twenty five patients of the total series, were subjected to a clinical examination in 1993, 9 to 54 months after meniscal suture. The Lysholm Knee Rating Score and the Tegner Activity Test were used. During 1999, these patients responded to a written questionnaire, based on the above mentioned rating scales. Among the 25 patients, there were 4 recurrences (16%), 2 fair results (8%) and one partial healing (4%). Eighteen (72%) patients, among which eight were treated using the arthroscopic technique, have shown favourable results, without any symptoms from the tibiofemoral joint, based on clinical examination and on the Lysholm Rating Scale and the Tegner Activity Test. When confronted with meniscal tears where there is doubt regarding the vascularity of the injured area, surgical repair in the avascular zone appears to provide a reasonable probability of healing, with good clinical outcome.

Adolescent↗
PubMedDate not supplied

Early weight bearing after posterior malleolar fractures: an experimental and prospective clinical study.

The distribution of axial load to the lower end of the tibia at different positions of the ankle joint for the anterior, middle, and posterior part of the joint was studied in both photoelastic models and fractured ankle joints in cadaveric specimens. Synthetic models were used to simulate both normal ankle joints and ankles with fractures of the posterior lip of the tibia. Tests were performed with the ankle at dorsiflexed, neutral-flexed, and plantarflexed positions of the ankle joint. The clinical portion of the study evaluated 15 patients with fracture of the posterior malleolus that comprised 0% to 33% of the articular surface. All patients had open reduction and internal fixation through a posterolateral or posteromedial approach, and were allowed full weight bearing in a cast within 7 days of surgery. In the simulated models, the posterior one fourth of the ankle joint remains unloaded in the majority of the cases. The stresses are greatly increased when the load is doubled and are mainly distributed to the 2 central quadrants. With additional axial load, the fourth quadrant sustained little increase in the load bearing. All patients have had an uneventful recovery. By the second postoperative month, they were able to walk normally and had a painless range of motion of the ankle. By the third month, all patients were able to undertake their daily activities, and all fractures were consolidated. The clinical relevance of this study is early weight bearing, after open reduction internal fixation of posterior malleolar fracture of the ankle joint, facilitates recovery, promotes fracture union, and allows the patient to assume normal activity by the third month after surgery.

Adolescent↗