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Summary Introduction Knee arthrodesis may be the last possible option for infected total knee arthroplasty (TKA) patients and in revision cases involving severe bone loss and/or extensor mechanism damages. Success in these situations depends on achieving good fixation assembly stability. We report bone fusion results using a fixation technique combining cross-pinning by two Steinman pins with a single-frame external fixator. Remission of infection at long-term follow-up was an additional criteria assessed for those cases initially treated for sepsis. Hypothesis This fixation modality improves fusion rates. Patients and methods In six of this series of eight patients (mean age: 59 years), surgery was performed in a context of infection: five cases of infected TKA, and one case of septic arthritis. In the other two cases, arthrodesis was respectively indicated for a severe post-traumatic stiffness compounded by extensor system rupture and for a fracture combined to a complete mechanical implant loosening. In three of the six infection cases, arthrodesis was performed as a single-stage procedure. All patients were operated on using the same technique: primary arthrodesis site stabilization by frontal cross-pinning with two Steinman pins, followed by installation of a sagittal external fixator frame. Results were assessed at a mean 8 year follow-up. Results All the arthrodeses showed fusion at a mean 3.5 months (range: 2.5 to 6 months) postoperative delay without reintervention. Weight-bearing was resumed at 2 to 3 months. The external fixator was removed at a mean 5.2 months. No recurrence of infection was observed over a mean follow-up of 8.2 years (range: 1 to 15 years). Three complications occurred: one hematoma, managed surgically; one supracondylar fracture treated orthopedically; and one osteitis, managed by surgical curettage. Discussion This knee arthrodesis technique proved effective, with no failures in this short series, especially in cases of primary infection. It is a reproducible means of osteosynthesis, with little subsequent morbidity. Fixation in two orthogonal planes seemed to provide the stability required to achieve bone fusion. This assembly avoids internal fixation, which is never risk-free in a context of primary sepsis. Level of evidence Level IV. Retrospective study.

Streams and riparian areas in the Bowron River watershed were assessed using the riparian management routine effectiveness evaluation, a protocol developed for postharvest operational monitoring in British Columbia. Located in the British Columbia interior, the study watershed has had several decades to recover since a period of intensive salvage logging from 1977 to 1987 in response to a spruce beetle ( Dendroctonus rufipennis ) outbreak. Correlations were found with site-specific watershed characteristics and attributes that are used to answer the protocol indicator questions. Channel width was the strongest covariate, exhibiting the most significant relationships with the stream and riparian attributes. Suggestions on how to adjust standard protocols for stream size and landscape heterogeneity are discussed and include the use of appropriate reference sites for baseline data. We used correlations with watershed characteristics and multiple regressions based on regional reference sites to predict upper and lower threshold values by which attribute measurements could be compared. Sites that were assessed above or below threshold values for an attribute were considered to be outside the range of natural variation and were given a failing score. Attributes with the most failures 20–30 years postharvest were disturbed ground, bare soil, undercut banks, and shade.

Adequate (wide or marginal and uncontaminated) margins and reconstruction are difficult to achieve when performing an internal hemipelvectomy for bone sarcomas involving the sacroiliac joint. We evaluated whether adequate surgical margins could be achieved and if functional outcomes could be predicted based on the type of resection and reconstruction. Forty patients had resections of the sacroiliac joint. Vertical sacral osteotomies were through the sacral wing (n = 2), ipsilateral sacral foramina (n = 27), sacral midline (n = 9), or contralateral foramina (n = 2). Iliac resections were Type I, Type I-II with partial or total acetabular re-section, or Type I-II-III. Surgical margins were adequate in 28 of 38 patients (74%), two (7%) of whom experienced local recurrence, compared with seven of 10 (70%) patients with inadequate margins. Reconstruction consisted of restoring continuity between the spine and pelvis. Resection of the entire acetabulum and removal of the lumbosacral trunk were the two main determinants of function, as assessed using the Musculoskeletal Tumor Society score. There were no life-threatening or function-threatening complications. Internal hemipelvectomy with a limb salvage procedure can be achieved with adequate surgical margins in selected patients. Functional outcomes can be predicted based on the type of resection and reconstruction, which helps the surgeon plan the procedure and inform the patient.

Resume L’etude rapporte les resultats d’une serie continue, prospective, multicentrique de 425 protheses Wallaby I ® conservant le ligament croise posterieur, posees par le groupe Guepar de 1992 a 1995. Le composant femoral de cette prothese presente des condyles asymetriques et divergents pour se rapprocher le plus possible de la cinematique du genou normal. Le plateau tibial en polyethylene est fixe. L’âge moyen des patients (70,5 ans), la repartition homme (28,3 %) et femme (71,7 %), l’etiologie (91 % d’arthrose primitive ou secondaire) et la deviation preoperatoire des genoux (65,6 % de varus > a 3° et 24 % de valgus > a 4°) etaient identiques a ceux qui sont publies dans la litterature pour ce type de prothese. Vingt-six protheses ont ete suivies moins de 1 an, 84 moins de 5 ans et 315 5 ans ou plus. Parmi les 399 genoux suivis plus de 1 an, il y a eu 4 infections (1 %) dont 3 ont necessite le changement de prothese, 3 fractures du femur toutes post-traumatiques, 2 descellements (1 global et 1 tibial) ayant necessite une reprise, 1 descellement tibial et 3 descellements rotuliens non-repris. Trois patients presentaient des douleurs anterieures du genou traitees avec succes par 2 resurfacages secondaires de la rotule et 1 section de l’aileron rotulien externe. Dix-neuf fractures de rotules (4,7 %) (dont 17 decouvertes fortuitement) constituaient la complication la plus frequente, sans retentissement fonctionnel. Le score moyen IKS genou postoperatoire etait de 90,5 points et le score moyen IKS fonction de 61,6 points. La mobilite moyenne etait de 110,5° ; 72,9 % des genoux etaient axes suivant la classification radiologique IKS, La survie de cette prothese a 8 ans (suivant Kaplan Meier) etait de 97,7 % quelle que soit la raison du changement de prothese et de 98,5 % en ne prenant comme evenement que la reprise pour descellement aseptique. Ces bons resultats corroborent ceux qui sont publies dans la litterature concernant les protheses conservant le ligament croise posterieur a plateau tibial fixe.

Responders to spill accidents need to have at their fingertips a method of rapid prediction of chemical cloud dispersion behavior and other relative information to protect the public from death and injury during evacuation of the affected area. A survey of 123 chemical spill accidents in the US where evacuations occurred revealed that available mathematical models were not used to predict cloud dispersion behavior while the event was under way, although modeling was sometimes done after the fact. The evacuation distances based on a given downwind concentration (level of concern) vary considerably, depending upon the chemical released and upon atmospheric turbulence resulting from solar insolation and wind blowing across surface features. Examples are presented. The problem is complicated because available mathematical models and look-up tales often do not give the same answer under the same conditions, nor do authorities agree on the concentration levels representing a level of concern on which to base evacuations. The responders to chemical spills need to be aware of these limitations, recognizing that modeling is a tool and does not represent ultimate truth. Yet modeling is useful to responders and is required by law in the US in developing possible accident scenarios under risk managementmore » plans as part of the Clean Air Act. Western Research Institute, in surveying the problems, has determined a need to communicate the benefits of modeling in a format designed for responders and others in the decision-making processes. A system for estimating evacuation distances has been developed for a hand-held computer for field use. The major features are that the user inputs the chemical spilled, spill location, time of day, cloud cover, and source spill information; evacuation distances based on a level of concern are calculated in seconds. The system is designed for planners and emergency response personnel without special modeling or computer skills.« less

Isolated injuries of the scapho-trapezial ligament complex are not well recognized. The ligament complex comprises the stout scapho-trapezial ligament, the floor of the flexor carpi radialis (FCR) tendon sheath and the scapho-capitate ligament. Between August 1991 and May 1992, we diagnosed and treated four cases of partial chronic post-traumatic lesions of this ligament complex. There was chronic pain at the base of the thenar eminence and instability of the thumb-index-middle finger pinch. Standard X-rays were normal. The diagnosis of ligament rupture was confirmed by mid-carpal arthrography showing filling of the sheath of FCR tendon. Surgical exploration showed complete rupture of the tendon sheath of FCR in two cases, associated in the other two cases with complete rupture of the scapho-trapezial ligament. Direct repair of the ligamentous elements was performed in all cases. The tendon of FCR was sutured to the tubercle of scaphoid to protect and to reinforce the ligament repair. The patients have been followed-up for between 6 and 12 months. All four patients recovered normal pinch strength to the middle finger. One patient suffered from chronic pain at work.

IRIS (Image Reading Instrument System), built by SAAB-SCANIA in cooperation with Physics IV, KTH, Stockholm, has been conceived with the intent of allowing interaction between three parties: an operator, a measuring machine and a computer.

T HE PURPOSE of this paper is to suggest a method for the allocation of selling effort among sales districts, and to compare it with others that have been used for the same purpose.1 The actions the business planner may take can be divided into groups among which there are complicated interactions. One convenient division is into actions pertaining to selling, production, and maintenance of inventory, respectively. If a new plan of selling is contemplated, the planner must realize that there will be repercussions through the rearrangement of sales in time. This change must be met by alterations in the schedule of production, or inventory, or both. There are also intertemporal relations among selling activities and sales. In general the variations in sales of two time intervals can be expected to be inverse, since some of the added sales of the first of the two periods may be simply anticipated replacement. However, sales effort can be devoted either to fitting the presentation of product to the customer, or to fitting the customer to the type of product the salesman wants him to buy. If money is spent in making a very careful study of the requirements of the customer, the increased purchasing of the first interval may be matched by later reorders induced by the satisfaction given by the original goods. On the other hand, if the