Anders Wykman

Biodegradable fixation of ankle fractures A roentgen stereophotogrammetric study of 32 cases

We performed a prospective randomized study comparing fixation with biodegradable polyglycolic acid (PGA) rods (n 15) or screws (n 17) in 32 selected displaced supination-eversion fractures. Immediate postoperative weight bearing in a walking cast was encouraged. An exact reconstruction of the ankle mortise was achieved in 26/32 ankles. Roentgen stereophotogrammetric analysis (RSA) revealed rather small movements in the ankle mortise during fracture healing. A better stability was achieved by using screws. After 6 months the clinical results did not differ. One case of sinus formation and one with local effusion occurred; both healed without impairing the clinical result. To compare the results with a nondegradable osteosynthesis technique, a reference group of supination-eversion fractures previously operated on with cerclage-wires, staples and pins was used. RSA showed better fracture stability with nondegradable fixation. The clinical results, however, did not differ.

Total hip arthroplasty: A comparison between cemented and press-fit noncemented fixation

Abstract This study compares cemented (Charnley) with noncemented (Honnart Patel-Garches) total hip arthroplasty. 150 patients with osteoarthritis, rheumatoid arthritis, and miscellaneous conditions were randomized into either group with 75 in each. Patients were evaluated over 5 postoperative years with examinations at 6 months, at 1 year, and then annually. Each examination involved clinical assessment, objective gait analysis, and radiographic examination. The Charnley group improved faster than the HP-Garches group during the first 2 years. At the last evaluation the results were excellent or good in 79% in the Charnley group and 70% in the HP-Garches group. In the HP-Garches group midthigh pain occurred, in 64%. Five, patients with Charnley prostheses (6.7%) and 14 patients with HP-Garches prostheses (18.7% had revision surgery to correct mechanical, loosening. Standard radiography revealed radiolucent zones in both groups, but this could not be related to the clinical outcome despite radiolucency being present in all noncemented replacements on the femoral side. Objective gait analysis confirmed inferior clinical results at 6 months in the HP-Garches group. There was no significant difference between the groups at the most recent evaluation. Our findings are not consistent with earlier optimistic expectations on press-fit noncemented total hip arthroplasties

Subsidence of the femoral component in the noncemented total hip: A roentgen stereophotogrammetric analysis

Roentgen stereophotogrammetric analysis was used in the evaluation of subsidence in eight noncemented femoral components of the HP-Garches prosthesis. After 2 years, seven components had subsided 0.6-3.9 mm, i.e., more than observed in some cemented prostheses. No distinct symptoms related to the micromotion appeared.

Activation of cascade systems by hip arthroplasty: No difference between fixation with and without cement

The acrylic bone cement has been regarded as a very potent activator of the hemostatic mechanisms. A battery of coagulation, fibrinolytic, and kallikrein variables were studied perioperatively in 21 patients undergoing hip arthroplasty with fixation of the prosthesis either with (Charnley) or without (HP-Garches) cement. Epidural analgesia was used and dextran 6 per cent as thromboprophylaxis. The HP-Garches procedure was shorter and caused less blood loss. No differences were found between the two surgical procedures regarding the activation of the cascade systems. The coagulation and fibrinolytic systems were activated early, but a week postoperatively the latter seems to predominate. A marked activation of the kallikrein system was apparent. Our study shows that despite thromboprophylaxis a marked activation of the coagulation, fibrinolytic, and kallikrein systems occurs in relation to hip arthroplasty irrespective of the use or nonuse of cement and irrespective of the volume of blood loss during surgery. It may be the reaming of the bone marrow that initiates the activation of the cascade systems.

Acetabular cement temperature in arthroplasty: Effect of water cooling in 19 cases

In 19 patients who underwent total hip arthroplasty the temperature was studied at the bone-cement interface in the acetabulum during the polymethyl methacrylate curing process. To evaluate the effect of fluid cooling, the patients were randomized into two groups: one group with no irrigation, the other with continuous irrigation with Ringer solution during cement curing. The temperature was recorded with a thermocouple at the bone-cement interface. Without water cooling, the median maximum temperature was 49 (41-67) degrees C. In 9 out of 11 patients the temperature elevations were sufficient to cause impaired bone regeneration or thermal necrosis of bone. Continuous water irrigation reduced the amount of heat at the bone-cement interface; median maximum temperature was 41 (37-48) degrees C.

Subsidence of porous coated noncemented femoral components in total hip arthroplasty

Roentgen stereophotogrammetric analysis was used in the evaluation of subsidence in nine noncemented femoral components of the Biomet Taperloc prosthesis. After 2 years three components had subsided 0.7-0.9 mm. No distinct symptoms related to the micromotion appeared. The subsidence in this investigation was smaller than the reported subsidence of other noncemented prostheses.

Knee motion after tibial osteotomy for arthrosis: Kinematic analysis of 7 patients

The in vivo kinematics of the knee in 7 patients with moderate medial gonarthrosis was analyzed before and 6 months after high tibial osteotomy using roentgen stereophotogrammetric analysis. The inclination of the femorotibial helical axis of rotation did not change with knee flexion or after surgery. The femorotibial rotation increased after surgery. No consistent change in patellar position after surgery was found. Patella translated laterally as the knee was flexed with a maximum patellar translation of about 15 mm and rotated internally with a maximum patellar internal rotation of about 15 degrees. There was no significant change in patellar translation or rotation after surgery. There was a good concordance regarding the size of the tibial wedge removed during surgery, calculated from the Hip-Knee-Ankle radiographs and from the roentgen stereophotogrammetric measurements.

Low polymerization temperature with Boneloc®:In vivo measurements in 11 hip replacements

We investigated the thermal properties of a new bone cement, Boneloc, during total hip replacement, using a thermocouple connected to a digital thermometer. In 10 of 11 cases the maximum temperature was below 43 degrees C at the bone-cement interface in the acetabulum. This is a considerable reduction in the polymerization temperature in comparison with earlier studies of conventional bone cement. We found no difference regarding the setting time of the cement.

Loopmogelijkheden na totale vervanging van het heupgewricht

>Wij bestudeerden 50 patienten voor en na enkelzijdige totale-heupvervanging (thv) en vergeleken hen, met behulp van loopanalyse, met 22 patienten die aan beide zijden waren geopereerd. De gemiddelde leeftijd van de patienten bij de eerste operatie was 65 jaar. De gemiddelde follow-up was voor de aan een zijde geopereerde patienten 53 maanden en voor de aan beide zijden geopereerde patienten 27 maanden na de tweede thv. De tijd tussen eerste en tweede thv was gemiddeld 24 maanden.