[In vitro studies on various PMMA bone cements: a first comparison of new materials for arthroplasty]. / In-vitro-Untersuchung unterschiedlicher PMMA-Knochenzemente--ein erster Vergleich neuer Materialien für die Endoprothetik.

AIM: Two clinically established PMMA bone cements (Refobacin Palacos R and Palacos R + G) and two newer cements not yet in widespread clinical use (Refobacin Bone Cement R and SmartSet GHV) were tested in vitro for practically relevant differences. METHODS: The tests included chemical analyses, handling properties and testing according to the ISO standard for PMMA bone cements. RESULTS: The results obtained indicate clearly that the copolymers used in Refobacin Bone Cement R and SmartSet GHV differ from those used in the Palacos cements. There were also significant differences in viscosity behaviour and waiting time (p < 0.01 for Palacos cements versus Refobacin Bone Cement R) as an expression of different handling properties. The hardening times under ISO 5833 conditions also differed significantly (p < 0.01 and p < 0.05 for Palacos cements compared with Refobacin Bone Cement R and p < 0.01 for Refobacin Bone Cement R compared with SmartSet GHV). CONCLUSION: In view of these differences in material properties, the clinical data from long-term use of the bone cements Refobacin Palacos R and Palacos R + G cannot be extrapolated to the newly developed PMMA cements Refobacin Bone Cement R and Smart GHV. Before broad clinical use of these cements, prospective clinical studies using RSA or DEXA and, as a second step, statistically powerful prospective comparative studies should be performed. Until these data are available, patients in whom Refobacin Bone Cement R and SmartSet GHV are used should be informed that the material employed deviates from the standard procedures for cemented joint replacement in the Scandinavian arthroplasty registers and that the long-term consequences cannot, in the final instance, be foreseen. This is essential in order to avoid later malpractice claims on the grounds of inadequate information.

[The value of wound drainage with or without suction]. / Die Wertigkeit von Wunddrainagen mit und ohne Sog. Eine prospektiv randomisierte Studie.

Even though the discussion for desisting from wound drainage has arisen, this is not reflected in the reality of surgical treatment. In more than 90% of all procedures wound drainage is used. It remains to be proven whether suction drainage actually is superior to gravity drainage in everyday use. In a random study with 200 patients it was proven that suction drainage shows no significant advantage in liquid quantum, haematoma and the frequency of complications. We conclude that the economically favourable gravity drainage can replace the more expensive suction drainage in most cases.

[Mechanical stimulation of venous blood flow in below-the-knee plaster cast]. / Mechanische Förderung des venösen Rückflusses im Unterschenkelgipsverband.

Physical methods became recently more important as an alternative to anticoagulation for prophylaxis of thromboembolism and were studied for their efficacy. The AV-impulse-system proved efficient in reducing thromboembolic complications in patients undergoing hip surgery by increasing the return of venous blood in the deep veins of the leg. In a preclinical trial we studied the influence of the AV-impulse-system and of active forefoot movement on venous blood return in 12 lower extremities of 6 healthy individuals immobilized in below the knee plaster casts. Our results show a significant increase in venous blood flow caused by the AV-impulse-system (p < 0.05) and by active forefoot movements (p < 0.05). Prevention of thromboembolic complications in trauma and orthopaedic patients immobilized in plaster cast seems possible by using the AV-impulse-system which significantly increases the venous blood flow independent from patient compliance.

[Multidimensional corrective osteotomy of the distal femur using a retrograde femoral nail]. / Mehrdimensionale Korrekturosteotomie des distalen Femur unter Verwendung des retrograden Femurnagels.

We report the case of a 62-year-old woman with marked valgus and limitation of extension of the right knee joint as the result of a supracondylar fracture of the femur, originally treated by internal fixation with a dynamic condylar screw. Two years later, revision osteotomy with retrograde femoral nailing was carried out to achieve variation and improve extension. Within a week of operation the patient's right leg was fully weight bearing with normal axial positioning. A retrograde locking nail provides satisfactory and stable internal fixation in cases of revision.

[Multidimensional corrective osteotomy of the proximal femur using the gamma-nail]. / Mehrdimensionale Korrekturosteotomie des proximalen Femurs unter Verwendung des gamma-Nagels.

We report on a 57-year-old patient suffering from a complex malposition of proximal femur after osteosynthesis using a condylar plate. For polyaxial correction of the proximal femur we successfully used an intramedullary hip screw system.

ACL reconstruction by patellar tendon. A comparison of length by magnetic resonance imaging.

In 50 knees the length of the anterior cruciate ligament (ACL), the patellar tendon, and the distance between the tibial tuberosity and the femoral origin of the ACL were evaluated by means of three-dimensional magnetic resonance imaging (MRI), which permits subsequent reconstruction of any sectional view. The measurements showed that the patellar tendon was always markedly longer than the ACL (mean 14.4 mm), but always shorter than the distance between the tibial tuberosity and the femoral insertion of the ACL (mean 19.2 mm). The mean lengths of the ACL and the patellar tendon were 38.2 mm and 52.6 mm, respectively. The mean distance between the femoral ACL origin and the tibial insertion of the patellar tendon was 71.8 mm. These results demonstrate that a distally based patellar tendon autograft alone (with the patellar bone block but without extension into the periosteum of the patella or the quadriceps tendon) cannot be placed anatomically correctly to the isometric femoral insertion of the ACL. When the patellar tendon is used for ACL reconstruction, it must be implanted as a free autograft. Nevertheless, considerable variations of length must be taken into account.

[Injury pattern in leaps from a window. A case analysis of 48 patients]. / Verletzungsmuster beim Fenstersprung. Eine Fallanalyse bei 48 Patienten.

We report about 48 patients who sustained a deceleration trauma after jumping out of a window. The average free fall height was 11.6 m. 45.8% of the patients suffered from psychic disorders. 12.5% were addicted to opiates or hallucinogenics. The lethality of the analysed group was 12.5%. Within the group of spinal injuries (66.7%) compression- and bursting vertebra fractures of the thoracolumbar spine dominate. Injuries of the osseus pelvic ring (62.5%) and the thorax (64.6%) were equally often in all free falls. Abdominal- (25%) and head trauma (35.4%) occurred less at the patients in our clinic. At the extremities a predeliction of injuries of joint near and joint building osseus structures was noticeable. Out of the 103 injuries of the lower extremities 57.3% concerned foot, ankle and the distal lower leg. With increasing height of the falls the rate of multi-injuries and chain fractures raised. Out of the 37 injuries of the upper extremities 40.5% concerned hand and distal forearm and 29.7% the elbow.

[Results of peripheral arterial vascular injury in polytraumatized patients]. / Ergebnisse peripherer arterieller Gefässverletzungen beim polytraumatisierten Patienten.

The therapeutic concept of limb salvage or immediate amputation is controversial in patients with multiple trauma. Sixty-three multiple trauma patients (injury severity score ISS > 18 patients) with blunt arterial injuries were investigated. Twenty-seven had injuries of the upper limb and 36 patients of the lower limb. In 33 cases a limb salvage procedure was performed (group I), while in 30 cases the limb was amputated (group II). Neither group showed a significant difference in age (I: 33 +/- 3, II: 30 +/- 3 years), ISS (I: 30 +/- 2, II: 29 +/- 2 patients), time of ischemia (I: 238 +/- 30, II: 203 +/- 20 min) ICU stay (I: 18 +/- 4, II: 19 +/- 4 days). Lethality and morbidity were slightly increased in group I (death: I: n = 8; II: n = 4; MOF: I: n = 5; II: n = 3; Sepsis: I: n = 11, II: n = 4). No differences were found in the incidence of local infections (I: n = 12, II: n = 10). Secondary amputations were performed in 7 patients after 12 +/- 2 days (range 3-40; median: 5 days). We conclude that limb salvage did not increase the risk for severe complications. Lethality and morbidity were related to the severity of the injury. To prevent complications, secondary amputations had to be performed early.

[Progression of arthrosis after alloplasty--what factors play a role?]. / Arthroseprogression nach alloplastischer Kreuzbandoperation--Welche Faktoren spielen eine Rolle?

From 87 patients who underwent anterior cruciate ligament (ACL) surgery with an alloplastic ligament (Trevira hochfest) the radiographs of 77 patients were examined by 2 physicians, who were not involved in the operation. They evaluated the increase of degenerative osteoarthritis according to the classification by Holz [12] finding a significant increase of degenerative osteoarthritis after surgery with a mean follow-up of 41.2 months. The ligament reconstruction was performed in 50 fresh ACL tears by reinsertion plus synthetic ligament protection and in 27 chronic instabilities with several failed previous operations by using the alloplastic ligament as an ACL prosthesis by means of a salvage procedure. Both investigators found a significant increase of degenerative osteoarthritis in both groups, but the chronically instable knees had a higher initial value. Patients with concomitant meniscus and/or posterior cruciate ligament (PCL) ruptures showed the highest increase of osteoarthritic changes; isolated ACL tears were found with very low degeneration. Considering the special profile of our collective, the factors that were found to as a risk of osteoarthritis and the comparison with the literature we could not find any indication for a relevantly increased risk of osteoarthritic progression using the Trevira hochfest ligament.

[Replacement of the anterior cruciate ligament by a PET prosthesis (Trevira extra-strength) as a salvage procedure in chronically unstable previously operated knee joints. Intermediate to long-term results of a clinical study]. / Der Ersatz des vorderen Kreuzbandes durch ein PET-Band (Trevira hochfest) als "Salvage Procedure" bei chronisch instabilen voroperierten Kniegelenken. Mittel- bis langristige Ergebnisse einer klinischen Studie.

Thirty-one salvage cases of chronically unstable previously operated knees were stabilized by an anterior cruciate ligament prosthesis of polyethyleneterephthalate (Trevira hochfest) and additional repair of concomitant lesions. The patients were followed up at yearly intervals. For the final follow-up after 4.4 years 27 patients could be evaluated clinically, radiologically and by several scores. The pre-operative Lysholm score was 59.8 (+/- 16.7). It was raised significantly by the operation to 75.4 (+/- 18.9) after 1 year, but then gradually decreased to 71.4 (+/- 19.6) at the final examination. Similar values were reached for the other scores (OAK, IKDC, VAS). The degree of activity (as estimated by the Tegner activity scale) increased from 2.0 (+/- 2.1) to 3.1 (+/- 1.9). Pre-operative anterior translation revealed a side-to-side difference of 7.5 (+/- 3.4) mm. The stability, which was restored by the operation, gave way a little in the first 2 years up to a side-to-side difference of 2.1 (+/- 2.5) mm, but then remained constant and was measured 2.3 (+/- 2.9) mm after 4.4 years. On the whole, the patients gained a significant improvement from the operation in all investigated parameters. Major complications included 5 ruptures of the synthetic ligament (1 by material fatigue), 1 avulsion of a staple, 1 supracondylar fracture due to 3 closely located staples, 4 cases of arthrofibrosis and 1 case of chronic knee irritation. The gradual deterioration of the operated knees within the follow-up period is mainly caused by the pre-existing chronic degenerative changes, which progress in spite of a sufficient stabilization of the central pivot.

[Calcified inclusions in a popliteal cyst as a rare cause of persistent knee pain and recurrent effusions]. / Kalkhaltige Konkremente in einer Poplitealzyste als seltene Ursache persistierender Kniebeschwerden und rezidivierender Ergüsse.

Popliteal cysts may occur with diseases of the knee and may cause several complications. We report about a patient with a popliteal cyst, that contained calcified concrements after a femur fracture and a complex knee injury and that we found to be a rare cause of persisting knee pain and effusions. The etiology of the concrements will be discussed, that we think are more likely to be posttraumatic loose joint bodies than traumatically induced chondromatosis.

[High-resolution 3-D imaging in MR tomographic knee joint diagnosis. Correlation with arthroscopy]. / Hochauflösende 3-D-Bildgebung in der kernspintomographischen Kniegelenksdiagnostik: Korrelation zur Arthroskopie.

84 knee joints were examined by a 3-dimensional MR method and the results correlated with subsequent arthroscopy. The findings showed good demonstration of the normal anatomical structures and excellent reliability for the diagnosis of meniscus tears (sensitivity 91%, specificity 95%), cruciate ligament lesions (sensitivity 90%, specificity 99%) and serious cartilage damage (sensitivity 100%, specificity 100%). Demonstration of mild cartilage damage (sensitivity 60%, specificity 99%) was better than with a spin echo technique but is not yet optimal. It is concluded that, by using a 3-dimensional technique, time-consuming spin echo sequences can be abandoned. Significant advantages of the 3-D method are the speed of the examination, narrow section thickness, marked flexibility in contrast rendering and the ability for multiplanar reconstruction.

Interface and biocompatibility of polyethylene terephthalate knee ligament prostheses. A histological and ultrastructural device retrieval analysis in failed synthetic implants used for surgical repair of anterior cruciate ligaments.

In a prospective clinical study of 54 patients with acute anterior cruciate ligament instability, 56 artificial ligaments made of polyethylene terephthalate (Trevira hochfest) were implanted to restore knee stability. The average follow-up of these artificial knee ligaments was 40.2 (12-79) months; five implants (10%) had to be explanted due to failure after an average of 17.8 (6-50) months. All explants were examined by histological and ultrastructural methods in a device retrieval analysis. With regard to short- and medium-term artificial ligament failure in the human knee joint, a non-isometric surgical implantation technique, inappropriate strain during rehabilitation and implant fatigue and wear were responsible for ligament failures.

Comparative evaluation of different anchoring techniques for synthetic cruciate ligaments. A biomechanical and animal investigation.

Under certain well-defined indications alloplastic material may be used in cruciate ligament surgery. The stability and survival of such a synthetic ligament is to a great extent dependent on the anchorage with which it is fastened to the bone. Most fixation methods have proved to be too weak or have revealed other essential drawbacks, resulting in clinical and experimental failure. A new ligament fixation device (LFD) was developed and tested biomechanically and in animal experiments. In the biomechanic investigation the new LFD was compared to single staples, double staples in the belt-buckle technique, and ligament guidance through additional bone tunnels (Z-technique). The tests were carried out on human cadaver knees, plastic bones, and dog stifle joints. The evaluated parameters were linear and maximum load, stiffness, and elongation. In addition, hysteresis tests were performed to assay the long-term resistance of the fixation. The tests showed a significant superiority of the LFD in all measured variables compared to the other anchorages. The pull-out strength, at 1866 +/- 43 N (cadaver knee), was about four times that for the single staple, and about twice as high as that for the double staple and Z-technique. The animal experiments were performed on German shepherd cross-breed dogs. In six animals the anterior cruciate ligaments were excised bilaterally and replaced by a 6-mm Trevira ligament, on one side anchored with staples in the Z-technique, on the other with the LFD. Postoperatively the dogs were allowed to move freely; no additional protection was employed. After 6 months the animals were sacrificed and the knees examined macroscopically, radiologically, microscopically, and by biomechanical testing. After half a year of implantation, the pull-out strength of the alloplastic ligament was 662 +/- 62 N for the LFD and 531 +/- 67 N for the staples. Three ligaments in the staple group and one in the LFD group had ruptured completely, and two ligaments partially, one in each group. The average anterior drawer in the LFD group was 2.8 mm, in the staple group 4.0 mm. In all cases the alloplastic ligament was separated from the bone by a fibrous interface. None of the fixation devices showed signs of loosening. There was no foreign body reaction around the anchorages. Major cartilage degeneration was observed in two stifle joints of each group, mainly associated with instability.

Which factors influence the progression of degenerative osteoarthritis after ACL surgery?

The knee radiographs of 77 patients were examined by two physicians not involved in the operation a mean of 41.2 months after implantation of a synthetic ligament (Trevira hochfest). They evaluated the increase of degenerative osteoarthritis on a five-grade scale (0-4) by Jonasch and Mohing as modified by Holz, and using the IKDC score. Fifty patients with acute rupture had the synthetic ligament implanted for protection of anterior cruciate repair. Twenty-seven patients had a salvage procedure with the alloplastic ligament functioning as a prosthesis. Both examiners found a statistically significant increase of degenerative arthritis. Patients with acute anterior cruciate tears had a lower degree of osteoarthritis on the day of surgery compared to the patients with chronic insufficiency, but the postoperative increase was identical in both groups. Statistical analysis revealed correlations between osteoarthric changes and several factors such as concomitant meniscus or posterior cruciate injury and demonstrated no correlation to the grade of postoperative stability or injuries to the medial or lateral collateral ligaments or capsule.

[Local antibiotic administration in osteomyelitis treatment--a comparative study with two different carrier substances]. / Lokale Antibiotika-Applikation in der Osteomyelitisbehandlung--Eine Vergleichsstudie mit zwei verschiedenen Trägersubstanzen.

Two antibiotic carriers (collagen sponge/PMMA-beads--loaded with gentamicin) for the treatment of osteomyelitis of long bones are compared in a randomised prospective study of 20 patients in respect of efficacy, safety and biocompatibility. In addition, the concentration of gentamicin in serum, urine and wound exudate was measured. This revealed marked differences. Gentamicin was released rapidly from the collagen sponge, leading to high levels in wound exudate and urine within the first 48 hours, with measurable but non-toxic concentrations in the serum. The liberation of gentamicin from the PMMA beads was much slower. This resulted in low steady levels in wound exudate and urine, and no detectable concentrations in the serum. The clinical outcome showed no differences between both methods of application. In 80% of the collagen sponge group and in 90% of the PMMA-beads group the osteomyelitis was completely allayed with disappearance of all infectious parameters. The number of re-operations was significantly higher in the PMMA group. It is recommended to use collagen sponges for the local treatment of osteomyelitis in cases that can probably be eradicated in a single surgical procedure, whereas PMMA beads should be applied in larger defects requiring a space-occupying function for further reconstructive operations.

[Suture protection of acute ruptured anterior cruciate ligament by the Pet-band (Trevira extra strong). Indications, technique results of a five-year study]. / Nahtprotektion des frisch rupturierten vorderen Kreuzbandes durch ein PET-Band (Trevira hochfest). Indikationsstellung, Technik und Ergebnisse einer Fünfjahresstudie.

In a prospective clinical study 56 acute tears of the anterior cruciate ligament (ACL) were treated between 1986 and 1991 by reinsertion and protection of the suture by means of a PET ligament (Trevira hochfest). The patients concerned were 31 men and 23 women (1 man and 1 woman had both knees operated on), with an average age of 39.7 years; 28 left and 28 right knees were affected. In 19 cases the ACL tear occurred in isolation, while in 37 concomitant intraarticular lesions were present. Nine patients had suffered multiple injury, and 3 had additional fractures distant from the knee. Haemarthrosis was encountered in 34 cases, and a clear effusion in 3 cases. The main causes of ACL rupture were sports injuries (n = 32), followed by traffic accidents (n = 14), activities of daily life (n = 6), and work accidents (n = 4). The preoperative diagnosis of ACL rupture was made correctly in 54 cases. After injury, 37 knees were operated on within the first 2 weeks, and 19 between the 3 and the 8 week. After arthroscopic repair of the concomitant lesions the alloplastic ligament was implanted isometrically by arthrotomy or miniarthrotomy through two bone tunnels and fixed to the bone with staples. Postoperative treatment included immediate continuous passive motion (CPM) and early weight-bearing with the protection of a brace. The patients were followed up at yearly intervals. At the last follow up, 6 years after the beginning of the study, 50 patients were examined clinically and radiologically, and the mean follow-up interval in these 50 was 40.2 months (12-79 months).(ABSTRACT TRUNCATED AT 250 WORDS)

[Experimental evaluation of various anchoring techniques for synthetic ligaments]. / Experimentelle Prüfung verschiedener Verankerungstechniken für synthetische Bänder.

One of the weak points of augmentation or replacement of cruciate ligaments by synthetic material is the fixation of these artificial ligaments to the bone. The present investigation examines the mechanical properties of a newly developed anchoring technique (ligament fixation device = LFD) in regard to linear and maximum load, stiffness, creep, and long-term durability compared to single staples, double staples in belt buckle technique, and passing the ligament through an additional bone tunnel. The tests are carried out on cadaver knees and plastic bones under standardized conditions with the same artificial ligament in all experiments (Trevira hochfest). The LFD shows a linear load of 1866 N in cadaver knees and 1874 N in plastic bones. The stiffness is 68.3 N/mm respectively 51.9 N/mm, the elongation at 500 N load 12.7 mm respectively 10.9 mm. In the hysteresis tests with submaximum loads the ligament/LFD-unit lasts 8515 cycles in the plastic bone and 4431 cycles in the cadaver knee. These results are significantly superior to all other fixation techniques concerning linear load, stiffness and long-term durability. They permit aggressive functional treatment and immediate postoperative weight bearing of the operated knee.

[Biological response following alloplastic replacement of the anterior cruciate ligament with PET-ribbon (Trevira hochfest)]. / Biologische Gewebereaktion nach alloplastischem Ersatz des vorderen Kreuzbandes durch PET-Band (Trevira hochfest).

A total of 97 cruciate ligament prostheses were implanted in 70 patients following acute and chronic cruciate ligament rupture; the average life of these prostheses being 3 years (8-53 months), 5 (5.15%) were removed due to failure after a mean of 9 (3-15) months. In 67 cases of chronic cruciate instability, 60 anterior and 7 posterior Trevira cruciate ligament prostheses were implanted, and 25 acute anterior and five acute posterior cruciate ligament ruptures were also treated with Trevira ligaments augmentations. The follow-up rate of patients with Trevira cruciate ligament repair was 97%. Of the explanted polyethylene-terephthalate (PET) devices, 4 had intra-articular ruptures at the bone tunnel entry and 1 had become unstable with no dislocation of staples. Investigation by scanning electron and light microscopy showed no bony ingrowth of the Trevira ligaments. Instead there was fibrous tissue ingrowth in all parts of the prostheses (intra-articular, bone tunnels and anchoring regions). The extent of foreign-body reaction at the Trevira ligament boundary differed with the intensity of mechanical strain at the three parts of the implants (intra-articular, bone tunnel, periosteum). Inflammatory cells and foreign-body giant cells were abundant close to the site of ligament rupture at the intra-articular entries of the bone tunnels. These cells were scarce at the intra-articular parts of the ligament prostheses and at the periosteal anchor points. Evaluation of the reasons for prosthetic ligament failure shows that (1) nonideal placement of bone tunnels and (2) inadequate strain during rehabilitation resulted in instability and rupture after anterior cruciate replacement with Trevira ligaments.

[Treatment of distal radius fracture. Surgical technique: bore wire osteosynthesis]. / Behandlung der distalen Radiusfraktur. Operative Technik: Bohrdraht-Osteosynthese.

The Kirschner wire fixation is mainly indicated in unstable types of Colles' and children's fractures of the distal radius. Out of 2760 distal radius fractures (1975-1989) 626 (20.7%) were treated operatively including 326 (11.8%) with K-wires. Primary operation was performed in 53.5% immediately after trauma. Exposing the sensitive radial nerval paths, 3-4 K-wires were inserted from the radial and the dorsoulnar aspect. The K-wire ends were covered subcutaneously. The clinical evaluation of a series of 226 patients according to the score of Lidström presented 79% excellent and good, 16% fair and 5% poor results. The clinical results correlate to the radiocarpal angle and radial shortening. Because of additional injuries to the ulnar complex give worse results in reposition, the ulnar styloid should be fixed.