B. Fink

Short- and medium-term results of the thrust plate prosthesis in patients with polyarthritis.

Abstract The thrust plate prosthesis is an implant with metaphyseal fixation to the proximal femur, which leaves the diaphyseal bone untouched. Therefore, this implant is preferred in younger patients. It is dependent on good bone quality in the proximal femur. Because the bone quality is reduced in patients with polyarthritis, this kind of endoprosthesis may have a higher failure rate than conventional stemmed endoprostheses in these patients. Therefore, in patients with polyarthritis, even short- and medium-term results of the thrust plate prosthesis should be analyzed. In all, 47 thrust plate prostheses were implanted in 42 patients with polyarthritis (29 with rheumatoid arthritis, 6 with juvenile chronic arthritis, and 7 with spondylarthritis) and followed prospectively. The average age at operation was 40.8 ± 10.7 years. Each patient was clinically and radiologically examined preoperatively, 3 and 6 months after the operation, and at the end of each postoperative year. The mean follow-up was 26.1 ± 10.7 months. The clinical findings were evaluated using the Harris hip score. Radiologically, 8 different zones of the thrust plate prosthesis were analyzed for radiolucencies. During the 1st year, the Harris hip score rose continuously from the preoperative average of 42.4 ± 6.5 points to 78.8 ± 10.3 points 3 months postoperatively, 82.3 ± 9.8 points 6 months postoperatively, and 86.8 ± 10.1 points 1 year after the operation. The subsequent examinations showed Harris hip score remained at the same level. Five patients (5 joints, 10.6%) had to undergo a revision of the thrust plate prosthesis due to aseptic loosening in 3 and septic loosening in 2. Six prostheses (12.6%) showed radiolucencies, mostly below the thrust plate in zones 1 and 2. Two of them were certainly radiologically loose, which raised the failure rate to 7 of 47 (14.8%). The thrust plate prosthesis improves function and alleviates pain in patients with polyarthritis to a satisfactory degree. Concerning the failure rate, this type seems to yield slightly worse results than cementless stemmed endoprostheses in the same patient group. Due to the preservation of the diaphyseal bone of the femur and the possibility of an unproblematic change to a stemmed endoprosthesis, the thrust plate prosthesis can be recommended for younger patients with polyarthritis.

The value of magnetic resonance imaging as postoperative control after arthroscopic treatment of osteochondritis dissecans.

Abstract The purpose of our study was to evaluate the value of MRI for preoperative arthroscopical planning in patients with osteochondritis dissecans. Based on the experience from 136 patients with osteochondritis dissecans of the knee or the ankle who were arthroscopically operated by retrograde drilling a follow-up study was carried out with 86 of them by clinical, radiological and postoperative magnetic resonance imaging (MRI) examinations. The evaluation was made by means of a visual analogue scale and a score system. The radiological findings were analysed according to the classification of Rodegerdts and Gleissner. The changes based on the MR images were classified according to our own pathoanatomical classification. The total score showed a significant improvement from 63.3 to 79.6 points (knee) and from 50.6 to 70.4 points (ankle). In 72% of the cases, the findings of the MR images showed a defective cartilage surface in the area of the osteochondritis dissecans lesion. An increase of signal in the osteonecrotic area could be seen in 51% of the cases when using a short-time inversion recovery (STIR) image. Especially in patients with postoperative failures, a high percentage of cartilage defects (grade III) could be detected on the MR images (PS 500/10). Uptake of gadolinium-diethylene triamine tetra-acetic acid was regarded as a sign for revascularization. Radiographs did not correlate with these changes detected in the MR images. This retrospective study of an operated osteonecrosis dissecans by MRI provides more detailed information about eventual revascularization of the osteonecrotic area. With this information a more detailed preoperative planing for further cases should be possible.

Histomorphometry of distraction osteogenesis during experimental tibial lengthening.

Objectives The aim of the current study was to analyze distraction osteogenesis histomorphometrically to investigate the amount of enchondral ossification adjacent to intramembranous ossification. Study Design Species-specific, longitudinal time study. Methods Lengthening of 25% of the right tibia was performed in 24 beagle dogs by callus distraction after osteotomy and application of a ring fixator. Distraction was started at the fifth postoperative day with a distraction rate of 0.5 mm twice a day. Twelve dogs were killed at the end of the distraction phase of 25 days (group A) and the remaining 12 dogs after an additional consolidation period of 25 days (group B). The tibia was removed from the distracted right leg and from the left control side of each animal, and longitudinal sections were cut and stained with Pentachrome. In all tibiae, an area of 0.5 × 2.4 cm within the endosteal bone was evaluated histomorphometrically with a Merz grid, and the results were compared between distraction and control side as well as between the dogs of group A and group B. Results On the distraction side, the typical signs of an increased de novo bone formation with a significant increase of osteoblasts and osteoid in group A, as well as an additional significant increase of bone volume and trabecular thickness in group B, were found. In all distraction cases, islands of cartilage formation, which underwent enchondral ossification, were found, besides membranous ossification. The ratio between membranous and enchondral ossification was found to be five to one. Conclusion Bone formation during distraction osteogenesis results from both membranous and enchondral ossification.

Dislocation of the polyethylene liner in hip arthroplasty: 6 patients with dislocation within 3 years.

We revised 6 patients with early destruction of the liner in a cementless press-fit acetabular cup. They had no signs of infection or evidence of trauma. The failures were probably due to rotation of the liner inside the metal shell and destruction of the polyethylene by the cutting edge of the metal. This early complication may be difficult to diagnose because of normal radiographs. We suggest that the manufacturer should provide the insert with a metal marker to make this complication easier to detect.

Electromyographically evident changes in skeletal muscles during tibial lengthening in dogs using the Ilizarov method

Abstract Twenty-four beagle dogs underwent a lower leg lengthening on the right side of 2.5 cm at a distraction rate of 2 times 0.5 mm per day using a circular fixator system. After a latency phase of 5 days and a distraction phase of 25 days, 12 dogs (30-day dogs) underwent electromyography (EMG) of the gastrocnemius muscle on the lengthened and on the control side. The remaining half of the dogs underwent EMG after a consolidation phase of 25 days following the end of distraction (55-day dogs). During every EMG, at least 20 different muscle potentials were analyzed, and the duration, amplitude, and number of phases were determined of each individual potential. The 30-day dogs had significantly longer potential phases on the lengthened side and insignificantly smaller amplitudes compared with the control side. Furthermore, we observed a slightly larger number of polyphasic potentials on the distraction side. In the 55-day dogs, no significant differences were observed in the various parameters between the lengthened and the control side. Comparing 30- and 55-day dogs, the duration of the potentials on the distraction side was not significantly shorter in the 55-day dogs, and the amplitude significantly higher. These findings could indicate combined neurogenous and myopathic alterations of the muscles during the early distraction phase which will be compensated during the later distraction period and the consolidation phase by reparative and reinnervation processes, leaving no lasting functional damage.

The significance of subacromial arthrography to verify partial bursal-side rotator cuff ruptures

BackgroundThe purpose of this study was to verify a partial bursa-side rupture of the rotator cuff (RC) using different imaging techniques with special emphasis on the validity of a specific method of subacromial arthrography (SAA).MethodsPatients (n=92, mean age 53.8xa0years) with a subacromial impingement syndrome underwent sonography, magnetic resonance imaging (MRI), and SAA. All diagnostic results were checked by subsequent arthroscopic surgery.ResultsOf 31 surgically verified ruptures, 17 showed a partial rupture located towards the bursa. These had been detected by MRI and ultrasound with a sensitivity of 64% and 41%, respectively, while SAA as a diagnostic tool yielded a sensitivity of 82%. In 14 cases of complete RC ruptures, all imaging techniques had a similar sensitivity of 86–93%.ConclusionIt appears that SAA is an adequate and valid diagnostic tool for the detection of partial bursa-sided RC ruptures. Ultrasound and MRI showed a comparably lower sensitivity. It is therefore concluded that SAA has clear advantages in the diagnosis of this defect with the consequence that open surgical techniques can be avoided.

Avascular osteonecrosis of the acetabulum

Abstractu2002Objective. To investigate the possible occurrence of osteonecrosis in the acetabulum in patients with non-traumatic necrosis of the femoral head. Design and patients. One hundred and seventy-nine patients with non-traumatic femoral head necrosis were assessed by MRI and radiography for the presence of acetabular necrosis. Three criteria were established to differentiate between osteonecrosis and osteoarthritic changes: (1) heterogeneous morphology and irregular contours of the lesion; (2) typical demarcation lines of osteonecrosis; (3) deficient accumulation of intravenous gadolinium in the affected regions. Results. In four patients histological confirmation of acetabular necrosis was obtained. The MR analysis of 22 acetabula (9.5% of those examined) showed changes which suggested osteonecrosis. No cystic lesions were demonstrated in the subchondral bone of any patient. Two cases of acetabular necrosis were found without an ipsilateral femoral head necrosis. In two patients of the 14 who had undergone total hip replacement following necrosis of the femoral head, aseptic loosening of the acetabular component was found. Conclusion. The study suggests that acetabular necrosis may be an accompaniment to aseptic necrosis of the femoral head. Further work is required to assess its importance in premature loosening of the acetabular element of total hip arthroplasty.

Critical evaluation of the indications for endoscopic lateral release of the patellofemoral joint

SummaryBased on the results of 70 patients with mild lateral tracking and lateral compression of the patella, intact (22 patients) or defective (20 patients) cartilage of the patellofemoral joint, and recurrent patellofemoral dislocation (28 patients) we present the technique, results, complications and indications for the lateral retinacular release and medial imbrication of the vastus medialis obliquus. The average age of the patients was 26.2 years (range 9–54). At time of follow-up (m = 64 months) the patients were examined clinically as well as radiologically. The results were evaluated according to a Crosby and Insall score. 77% of the patients with mild lateral tracking and lateral compression (lateral release) were satisfied with the operative result (visual analog scale), as well as 68% of the patients with recurrent patellofemoral dislocation (lateral release and medial imbrication). Only 45% of the patients with patellofemoral arthritis (lateral release) reported an improvement in their condition after this procedure. The Crosby and Insall score showed significant improvement but did not show any difference between the 3 groups. 13% of the patients showed an abnormal lateral tracking of the patella in active motion. The passive patellar glide test showed patellar hypermobility to the lateral side in 37% of the cases and to the medial side in 80%. X-rays of both knees showed a sulcus angle of 143°. No progression in osteoarthritis in the operated patellofemoral joint was found. Hemarthrosis complicated a high number of cases in the early postoperative period, and in 3 cases an open revision was necessary. Clinical relevance: According to our results patients with patellar compression syndrome without patellofemoral arthrosis and patients with recurrent dislocation or subluxation of the patella are good candidates for endoscopic lateral release and medial imbrication of the medial vastus obliquus. In a young population endoscopic lateral release is a relatively simple surgical procedure making an open technique in failed cases possible later on.RésuméDans cet article nous présentons la technique, les résultats ainsi que les complications et les indications de la section de laileron rotulien externe et la capsulorhaphie interne, à partir des résultats obtenus par lexamen de 7o malades souffrant les uns dune légère latéralisation rotulienne externe et dune hyperpression fémoro-patellaire externe (42 malades), les autres dune luxation recidivante de la rotule (28 malades). La moyenne dâge était de 26.2 ans (entre 9 et 54 ans). Au moment de lexamen de contrôle (m=64 mois) les malades ont été soumis à un examen clinique et radiologique. Les résultats ont été évalués conformément au score de Crosby et de Insall. 77 % des patients traités par relâchement latéral externe étaient satisfaits du résultat de lopération (score analogue visuel) et 68 % des patients traités par capsulorhaphie. Par contre seulement 45 % des malades souffrant dune ar-throse fémoro-patellaire traités par relâchement latéral externe parlaient dune nette amélioration. Le score dit de Crosby et Insall donnait des résultats très significatifs mais ne montrait aucune différence parmi les résultats obtenus dans ces trois groupes. 13 % des malades souffraient dun glissement de la rotule anormal en mobilisation active. Le test de glissement passif de la rotule montrait une hyper-mobilité de la rotule vers le côté latéral dans 37 % des cas et vers le côté médial dans 8o % des cas. Les radiographies des deux genoux montraient un angle de sulcus accru de 143 %. Cependant, aucune progression de larthrose na pu être relevée dans les articulations fémoro-patellaires opérées. Une hémarthrose post-opératoire précoce, nécessitant une révision, a été constatée dans un grand nombre de cas. Intérêt clinique: Vu les résultats sur les malades ayant souffert dun syndrome dhyperpression rotulienne sans arthrose patello-fémorale et les malades souffrant dune luxation ou subluxation récidivante de la rotule, ces patients sont de bons candidats pour une section endoscopique de laileron rotulien externe et éventuellement pour capsulorhaphie interne. Dans une population relativement jeune la section endoscopique de laileron externe est une technique chirur-gicale relativement simple qui peut néanmoins être suivie par une technique “ouverte” en cas de défaillance de la première procédure.

The Transfemoral Approach for Removal of Well-Fixed Femoral Stems in 2-Stage Septic Hip Revision

BACKGROUNDnThe value of a transfemoral approach for removal of well-fixed infected hip arthroplasties in 2-stage revision is unclear, especially whether cerclages for closure of the flap in the first step lead to higher reinfection rates and whether reopening of the flap for reimplantation of a hip arthroplasty leads to a lower union rate of the bony flap.nnnMETHODSnSeventy-six septic 2-stage revisions via a transfemoral approach with cerclages for closure of the flap in the first step and reopening of the flap for reimplantation were followed prospectively for a mean period of 51.2 ± 23.2 (24-118) months.nnnRESULTSnThe union rate of the bony flap after reimplantation was 98.7%, and no recurrence of reinfection was recorded in 93.4% of all cases. Subsidence of the stem occurred at a rate of 6.6%, dislocation at a rate of 6.6%, and there was no aseptic loosening of the implants. The Harris Hip Score was 62.2 ± 12.6 points with the spacer and 86.6 ± 15.5 points 2 years after reimplantation. Nine fractures (11.8%) of the flap occurred during the operation because of osteolytic or osteoporotic weakness of the flap itself, but these all healed without further intervention.nnnCONCLUSIONnThe transfemoral approach is a safe method for septic revision of well-fixed hip prostheses, and the use of cerclage wires for closing the osteotomy flap in the first stage does not appear to lead to a higher reinfection rate. Similarly, the reopening of the flap does not appear to decrease the union rate of the flap.

Osteochondrosis dissecans am oberen Sprunggelenk

Klassifikation und Stadieneinteilung: Basierend auf den Erfahrungen einer retrospektiven Studie von 136 Patienten, die nach arthroskopischer Therapie einer Osteochondrosis dissecans am Sprunggelenk nachuntersucht wurden, konnten radiologische, kernspintomographische und arthroskopische Befunderhebungen dazu herangezogen werden, eine Klassifikation der Osteochondrosis dissecans (OD) in 6 Stadien vorzunehmen. Zusätzlich wurden 17 jugendliche Patienten einer prospektiven Studie unterzogen, wobei prä- und postoperativ angefertigte Kernspintomographien (MRT) zur Auswertung gelangten. Zur Stadieneinteilung wurden Lokalisation, Herdausdehnung, kortikaler Knochen, Knorpeloberfläche, mögliche Ödemeinlagerung, perifokaler Bereich sowie v.u2002a. die Einlagerung von i.u2002v. verabreichtem Gadolinium (Magnevist) in der Beurteilung berücksichtigt. Therapie: Anhand des nachgeprüften arthroskopischen Therapieerfolgs und zusätzlich erhobener klinischer Befunde mittels eines speziellen Sprunggelenkscores wird unter Berücksichtigung des Patientenalters und der vorliegenden bildgebenden Parameter eine Therapieempfehlung gegeben. Classification: Based on the experiences of a retrospective study of 136 patients treated arthroscopically for osteochondritis dissecans (OD) of the ankle, X-rays, magnetic resonance imaging (MRIs), and arthroscopic findings were used for a new classification (6 stages) of OD. Additionally, 17 patients from a prospective study could be included for whom pre- and postoperative MRIs were available for evaluation. The classification took into consideration localization, size of the necrotic area, cortical bone, cartilage, possible assessment of edema, perifocal area as well as any uptake of gadolinium (Magnevist), which had been given i.v. before MRI was performed. Therapy: Taking into consideration the arthroscopic state, the parameters of the imaging modalities, and additional clinical findings classified by a special ankle score, an age-related recommendation for therapy is given.