Aims: The purpose of this study was to evaluate the patterns of wear of patella implants in total knee arthroplasty. Materials and Methods: The pattern of polyethylen wear of 17 patella components, 5 Kinematic and 12 Total Condylar, retrieved after an average of 80 month in situ, was studied. The primary diagnosis was osteoarthritis in all cases. The implants were retrieved from 6 men and 11 women with an average age of 64 years at the time of arthroplasty. Their average height was 168 cm and average weight was 68.5 kg. In all cases revision was performed for mechanical loosening of one or several components. Using light microscopy, the articulating surface of each patella component was analyzed for six modes of damage: Polishing, Delamination, Surface deformation due to cold flow, Scratching, Pitting and Abrasion. To describe the damage the surface of the patella component was divided into four sections. The contact stresses between the patellar and femoral components were calculated in relation to the areas of wear. Volumetric wear could not be accurately established. Results: The “Papion” pattern indicated higher rate of wear at the periphery of the patellar implants. Four modes of damage were observed: polishing in 13, delimitation in 12, cold flow in 6 and scratching in 3. The median total area of polyethylene damage was for polishing 76.5%, delimitation 70.6%, cold flow 35.3% and scratching 17.6%. The average contact stress on the nonconforming Total Condylar patella component was 12.9 Kgf/mm². It was significantly higher (p< 0.002) than the average contact stress on the conforming Kinematic patellar component – 2.9 Kgf/mm². The area of wear was smaller, 357.2 mm² for the nonconforming Total Condylar, than for the conforming Kinematic patella 439.2 mm². However, this difference was not statistically significant. The average weight of the patients with the Kinematic knee (74.5 kg) was higher as compared to the patients with Total Condylar knee (66 kg) but the difference was not significant. Conclusions: The high incidence and pattern of wear of the patella components indicates a basic fault in the design of the patellar implants. In our opinion there is insufficient thickness of the polyethylene in most points of contact specifically at the periphery. We suggest improving two mechanical properties: adequate thickness of the entire polyethylene implant including the periphery and conforming articulating surfaces of the periphery of the dome.

Aims: The purpose of this study is to evaluate the efficacy of radiographic and computed tomography pre-operative planning and postoperative results of total knee arthroplasty. Material and methods: 124 procedures of Corin MTK total knee arthroplasty were pre-formed since July1998.A strict radiological and CT evaluation was done prior to and following the surgery and accompanied the clinical evaluation and follow up. A cohort of 32 patients is presented in details regarding the imaging pre-operative planning and the post-operative results. The radiological data included: 1. Angle of frontal deformity, 2. Angle of instability, 3. Fi-Fc – distance from the tip of the fibular head to the distal part of the lateral femoral condyle, 4. Frontal inclination angle of tibial component, 5. Frontal inclination angle of femoral component, 6. Sagital posterior inclination of tibial component, 7. Sagital posterior inclination angle of the femoral component, 8. The distance from the patella to the knee center of motion. The computed tomography data included: 1. The actual dimensions of the patella, tibia and femur, 2. The preoperative angle between the posterior condylar line and anterior condylar line, 3. The angle between the posterior condylar line and the transepicondylar line, 4. The Angle of external rotation of the femoral component, 5. The Angle of external rotation of the tibial component, 6. The distance of lateralization of the femoral and tibial components. Results: The desired value of external rotation of the femoral component was 6–80. Measuring the pre operative angle between the posterior condylar line and the transepi-condylar line helped to determine the degree of external rotation intraoperatively. The mean external rotation of the femoral component in our cohort was 6.73.

Measuring the the angle of external rotation of the tibial component preop helped to determine the extent of external rotation of the tibial component intraoperatively.

A significant decrease of the postop Q angle was noticed in all patients. Conclusion: Radiographic and computed tomography postoperative data reflects the value of the preoperative planning of total knee arthroplasty.

Purpose: The purpose of this study is to evaluate the efficacy of radiographic and computed tomography pre-operative planning and postoperative results of total knee arthroplasty.

Material and methods: 110 procedures of Corin MTK total knee arthroplasty were performed since July 1998.

A strict radiological and CT evaluation was done prior to and following the surgery and accompanied the clinical evaluation and follow up. A cohort of 32 patients is presented in details regarding the imaging pre-operative planning and the post-operative results.

The radiological data included: 1. Angle of frontal deformity; 2. Angle of instability; 3. Fi-Fc – distance from the tip of the fibular head to the distal part of the lateral femoral condyle; 4. Frontal inclination angle of tibial component; 5. Frontal inclination angle of femoral component; 6. Sagital posterior inclination of tibial component; 7. Sagital posterior inclination angle of the femoral component; 8. The distance from the patella to the knee center of motion.

The computed tomography data included: 1. The actual dimensions of the patella, tibia and femur; 2. The preoperative angle between the posterior condylar line and anterior condylar line; 3. The angle between the posterior condylar line and the trans-epicondylar line; 4. The angle of external rotation of the femoral component; 5. The angle of external rotation of the tibial component; 6. The distance of lateralization of the femoral and tibial components.

Results: The desired value of external rotation of the femoral component was 6–8°. Measuring the pre-operative angle between the posterior condylar line and the trans-epicondylar line helped to determine the degree of external rotation intraoperatively. The mean external rotation of the femoral component in our cohort was 6.73.

Measuring the angle of external rotation of the tibial component preop helped to determine the extent of external rotation of the tibial component intraoperatively.

A significant decrease of the postop Q angle was noticed in all patients.

Conclusion: Radiographic and computed tomography postoperative data reflects the value of the preoperative planning of total knee arthroplasty.

Purpose: The purpose of this study was to evaluate the patterns of wear of patella implants in total knee arthroplasty.

Material and methods: The pattern of polyethylene wear of 17 patella components, 5 kinematic and 12 total condylar, retrieved after an average of 80 month in situ, was studied. The primary diagnosis was osteoarthritis in all cases. The implants were retrieved from 6 men and 11 women with an average age of 64 years at the time of arthroplasty. Their average height was 168 cm and average weight was 68.5 kg.

In all cases, revision was performed for mechanical loosening of one or several components. Using light microscopy, the articulating surface of each patella component was analyzed for six modes of damage: polishing, delaminating, surface deformation due to cold flow, scratching, pitting and abrasion.

To describe the damage, the surface of the patella component was divided into four sections. The contact stresses between the patellar and femoral components were calculated in relation to the areas of wear. Volumetric wear could not be accurately established.

Results: The “Papion” pattern indicated higher rate of wear at the periphery of the patellar implants.

Four modes of damage were observed: polishing in 13, delimitation in 12, cold flow in 6 and scratching in 3. The median total area of polyethylene damage was for polishing 76.5%, delimitation 70.6%, cold flow 35.3% and scratching 17.6%. The average contact stress on the nonconforming Total Condylar patella component was 12.9 Kgf/mm2. It was significantly higher (p< 0.002) than the average contact stress on the conforming Kinematic patellar component – 2.9 Kgf/mm². The area of wear was smaller, 357.2 mm2 for the nonconforming Total Condylar, than for the conforming Kinematic patella 439.2 mm2. However, this difference was not statistically significant. The average weight of the patients with the Kinematic knee (74.5 kg) was higher as compared to the patients with Total Condylar knee (66 kg) but the difference was not significant.

Conclusions: The high incidence and pattern of wear of the patella components indicates a basic fault in the design of the patellar implants. In our opinion there is insufficient thickness of the polyethylene in most points of contact, specifically at the periphery. We suggest improving two mechanical properties: adequate thickness of the entire polyethylene implant including the periphery and conforming articulating surfaces of the periphery of the dome.

Purpose: The purpose of this study is to present our imaging results of Corail stem implant after 11 years of follow-up.

Material and Methods: 31 patients that underwent total hip arthroplasty between 1990–1996 in which Corail stem was implanted were included in this study.

The imaging parameters that were collected from patient X-rays were: radiolucent line, osteolysis, subsidence, cortical hypertrophy, cortical thinning, undersizing, distal pod, rounded calcar, cupping and sagging.

Results: Our of 31 patients, 21 were man and 10 were women, the mean age was 60.5 years (range 32–77y), 6 were bilateral, 3 patients had trochanteric osteotomy before surgery. The mean follow-up period was 8.2 years (range 5–11y).

No sign of loosening were observed in any patient, 23 stems were implanted in neutral position, 2 stems in valgus and 6 in varus position. In 15 patients stem was undersized. In 23 patients distal pod was observed, 19 patients had trochanteric osteopenia, in 10 patients cupping was noticed and in 6 patients cortical thinning was observed. Five patients showed proximal osteopenia and in 5 patients sagging of few millimeters was noticed during the first years after surgery. No radiolucent line, osteolysis, subsidence and cortical hypertrophy were observed up to 11 years follow-up.

Discussion: No signs of loosening were observed in all stems after 11 years of follow-up.

Conclusion: In our opinion Corail stem for THA is a very reliable implant.

Purpose: The purpose of this study is to present an alternative method of treatment for periprosthetic fractures of the femur.

Materials and methods: 8 patients, 4 of them after total hip arthroplasty and 4 after Austin Moore hemi-arthroplasty had periprosthetic fracture of the femur. By the classification of Beals and Towers, patients with fractures types IIIa, IIIb and IV were included in this study.

All were treated by retrograde intramedullary nailing.

The surgical procedure was done closed or open by insertion of a retrograde intramedullary nail. Distal interlocking was achieved by two transversal screws.

Clinical and radiological follow-up was performed during the first year after operation.

Results: One patient died in the postoperative period from cardiac complication and 2 failed to attend to follow-up. In 5 patients, complete healing of the fracture was noticed and return to daily activities.

Conclusions: Retrograde intramedullary nailing of the femur may be a good solution of treatment for periprosthetic fractures of the femur.

Purpose: The purpose of this study was to clinically evaluate the efficiency of extracorporal shockwave therapy for enthesopathies.

Materials, Methods and Results: 26 patients with mean age of 51 (range: 18–73) which suffered from enthesopathies in different regions were included in this study. Prior to treatment pain and function were assessed subjectively by using a visual analog scale ranging from 1 (maximum pain/minimum function) to 10 (no pain, full function).

The follow-up period was 6–18 months with an average follow-up period of 13 months.

All patients were treated with ESWT. One to three treatment sessions were provided to each patient with an interval of one week between the sessions. After all sessions were finished, pain and function were reassessed in the same method that was used before the beginning of the treatment.

The overall mean pain value was 1.96 before the treatment and 5.92 after the treatment.

8 patients (30.7%) reported no pain at all after the treatment and in 6 patients (23%) a significant improvement in pain was achieved. 7 patients (19%) reported of only slight relief of pain and 4 patients (15.4%) reported no change in pain level. Only in one patient (3.9%) worsening of the pain was observed.

The overall mean function capacity was 5.76 before the treatment and 8.65 after the treatment. 11 patients (42%) returned to full functional capacity and in 7 patients (27%) a significant improvement in functional capacity was observed. In 8 patients (30.7%) no change in the functional capacity was noticed.

Good results of improvement in pain severity and functional capacity were observed in cases of plantar fasciitis and tennis elbow.

Conclusion: We think the EWST is helpful for treatment of enthesopathies, especially plantar fasciitis and tennis elbow, and suggest to include it in treatment algorithms.

Objective: To point out the strict rules of surgical technique required for the success of newly applied advanced technology.

Materials: 73 hips in 70 patients, aged 23 to 71 years old, underwent total hip arthroplasty using ceramic bearing surfaces implants. 62 were a primary procedure, and 11 were revision surgery.

Results: One complication of fracture of posterior ace-tabular wall was registered in a patient with ankylosing spondylitis, four early dislocations that were reduced closed, and one case of late postoperative death in a cardiac high-risk patient. No other complications were recorded since the first operation in May 1999. All patients had remarkable pain relief, improved range of motion and improved function.

Discussion: The tribological properties of the ceramic articulating surfaces favors them as the preferred technology for future orthopaedic implants. By reducing wear to a minimum the choice of ceramics seems to be justified. The main concern is fragility versus toughness. We have formulated ten rules of proper surgical technique concerning: accurate fit of the components, accurate orientation of the components, stability of the joints, adequate tissue tension, caring for debris and prevention of metal transfer due to ceramic-metal touch.

Conclusions: While our clinical experience is still short term, it appears that applying a rigorous and uncompromising surgical technique with ceramic bearing surfaces is essential for the clinical success of this potent bio-material.

Based on our experience, our recommendations are that:

Ceramic bearing surfaces T.H.A.-s should be performed in specialized centers.

Objective: To present our innovative surgical technique that simultaneously provides optimal femorotibial tracking and patellofemoral tracking in total knee arthroplasty.

Material and methods: A total of 127 patients underwent total knee arthroplasty using new criteria for femoral, tibial and patellar preparation and placement of their respective components. The technique consisted of intraoperative determination of the rotation of the femoral and tibial components, lateralization of the femoral and tibial components and medialization of the patellar component, thus reducing the Q-angle. It provided excellent tracking of the tibiofemoral and patellofemoral joints without retinacular release.

Results: At a follow up of up to 3 years, 90% of patients gained up to 120 degrees of motion within first 6 months. Rest pain score [10-0] improved from 5.2 to 0.8. Activity pain score [10-0] improved from 9.0 to 2.0. Stair climbing [0–10] improved from 2.8 to 7.1. Walking score improved from 3.2 to 7.3. ADL function improved from 4.3 to 7.1. Our complications included 1 case of postoperative traumatic fracture of the patella, that healed spontaneously, 1 deep infection which responded well to open lavage, and 6 cases of delayed wound healing that required secondary closure. One patient died of unrelated cause. No fracture, loosening, component failure or instability was recorded. None of the implants required removal.

Conclusion: Implementation of our 10 rules concept of surgical technique gave early excellent results, and we recommend it as a technique universally applicable in total knee arthroplasty.

Nuclear magnetic resonance imaging (MRI) was used to study the normal knee. As well as revealing bone quality, MRI provided useful information on intra-articular and extra-articular soft tissues. Midsagittal views gave clear images of the cruciate ligaments, and of the patellar and quadriceps tendons. Parasagittal views were the best for delineating the menisci which, like ligaments and tendons, are of low intensity; the semimembranosus tendon and its insertion to the proximal tibia were also seen clearly in these views. The cruciate ligaments and menisci, though visible in the coronal view also, were better seen in the sagittal view. Axial views provided information on the structure of the patella, its cartilage, the patellofemoral joint and posterior soft-tissue structures.

The soft tissue response to carbon fibre was studied histologically one and a half years after being used to reconstruct the lateral collateral ligament of the human knee. A remarkably consistent pattern was seen in the induced ligament. The basic pattern was a "composite unit", consisting of a core of carbon fibre enveloped in a concentric manner by coherent layers of fibroblasts and collagen fibres. This new structure seemed to have been induced by continuous irritation caused by the physical structure of the carbon fibres; it is unlikely ever to acquire the structure of a natural ligament. However, it is biologically compatible and is biomechanically sufficient as long as the entire tow of carbon fibres is preserved.