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T Miclau

Publications and source records attributed to T Miclau.

At least 37 records · Page 2Linked to original sources
PubMed1998

Effects of percutaneous and conventional plating techniques on the blood supply to the femur.

A cadaveric arterial injection study was performed to study the effects of percutaneous and conventional surgical plating techniques on femoral vascularity. Sixteen-hole dynamic condylar screw and condylar buttress plates were applied on the proximal and distal shafts, respectively, of intact femora in ten human cadavers. On one side, the plate was inserted using a lateral conventional plate osteosynthesis (CPO) technique with elevation of the vastus lateralis muscle to expose the shaft. On the contralateral side, the plate was inserted percutaneously beneath the muscle using a minimally invasive plate osteosynthesis (MIPPO) technique. After plating, blue silicone dye was injected through the common femoral artery. A dissection was then performed to identify the femoral perforating arteries (PAs). The pattern of periosteal filling of the injected dye was analyzed. The MIPPO technique maintained the integrity of the PAs and exhibited superior periosteal perfusion. The results of this study indicate that the MIPPO technique maintains femoral vascularity and perfusion better than the CPO technique.

Aged↗
PubMed1998

Intraoperative control of axes, rotation and length in femoral and tibial fractures. Technical note.

In an effort to limit the amount of soft tissue dissection at the fracture site, indirect reduction and minimally invasive fixation techniques have been developed to treat femoral and tibial fractures. These techniques, which do not rely upon anatomical reduction of the fracture fragments, are technically difficult. Correct limb length, axial alignment in the frontal and sagittal plane, and rotation must be assessed using means other than open reduction. In this technical note, some simple and effective intraoperative clinical examination and radiographic techniques to determine limb alignment are described. These include: the 'cable techniques' for the determination of varus-valgus malalignment; the 'hypertension test', 'radiographic recurvatum sign', 'tibial plateau sign', and 'meterstick technique' for length analysis; and the 'hip rotation test', 'lesser trochanter shape sign', 'cortical step sign', and 'diameter difference sign' for rotational analysis. For each of the listed techniques, basic principles, technical instructions, limitations, advantages, and disadvantages are described.

Bone Malalignment↗
PubMed1998

Experimental study of distal interlocking of a solid tibial nail: radiation-independent distal aiming device (DAD) versus freehand technique (FHT).

OBJECTIVES: Recently, radiation-independent aiming devices for the tibia that compensate for insertion-related implant deformation have been developed, but the benefits of such systems have not been determined. This study prospectively evaluated the duration of the nailing procedure, the length of radiation time, and the accuracy of interlocking screw placement when using a radiation-independent distal aiming device (DAD) versus the freehand technique (FHT). MATERIALS AND METHODS: In an oblique cadaveric tibial fracture, a surgeon inexperienced in both techniques (DAD and FHT) performed statically locked intramedullary nailing. RESULTS: For the DAD and the FHT, respectively, the total operation time was 25.4 +/- 11.3 (mean +/- standard deviation) versus 30.9 +/- 14.3 minutes (p = 0.029), the distal locking time was 16.7 +/- 8.6 versus 21.9 +/- 10.5 minutes (p = 0.004), the total fluoroscopy time was 9 +/- 5 versus 93 +/- 34 seconds (p < 0.0001), the distal locking fluoroscopy time was zero versus 88 +/- 33 seconds (p < 0.0001), and the screw wear was -0.7 +/- 5.2 versus 26.8 +/- 31.6 micrometers (p = 0.001). The failure rate was 1.6 percent (one of sixty screws) in both groups. CONCLUSION: These results suggest that the DAD can eliminate the need for radiation during placement of distal interlocking screws.

Adult↗
PubMed1998

Plate osteosynthesis of the distal femur: surgical techniques and results.

Over the past three decades, the techniques for internal fixation of the distal femur have evolved to provide reliably successful results. The improved outcomes of plate osteosynthesis of distal femur fractures are because of better implants, techniques of anatomic reduction and soft tissue handling, and post-fixation stability with early motion. We review the traditional Arbeitsgemeinschaft für Osteosynthesefragen (AO) surgical techniques for plate osteosynthesis of the distal femur and the results reported using these methods.

Bone Plates↗
PubMed1997

The evolution of modern plate osteosynthesis.

Plate osteosynthesis is still recognized as the treatment of choice for most articular fractures, many metaphyseal fractures, and certain diaphyseal fractures such as in the forearm. Since the 1960s, both the techniques and implants used for internal fixation with plates have evolved to provide for improved healing. Most recently, plating methods have focused on the principles of 'biological fixation'. These methods attempt to preserve the blood supply to improve the rate of fracture healing, decrease the need for bone grafting, and decrease the incidence of infection and re-fracture. The purpose of this article is to provide a brief overview of the history of plate osteosynthesis as it relates to the development of the latest minimally invasive surgical techniques.

Bone Plates↗
PubMed1997

Minimally invasive plate osteosynthesis and vascularity: preliminary results of a cadaver injection study.

A cadaver arterial injection study was performed to analyse the vascular supply to the femur and to study the effects of two surgical plating techniques on femoral vascularity. A 16-hole LC-DCP was applied on the intact femora of five fresh human cadavers. On one side, the plate was inserted using a conventional lateral plate osteosynthesis (CLPO) technique with elevation of the vastus lateralis muscle to expose the shaft. On the contralateral side, the plate was inserted percutaneously beneath the muscle using a minimally invasive plate osteosynthesis (MIPO) technique. After plating, blue silicone dye was injected through the common femoral artery. Cadaveric dissection was then performed to identify the femoral perforating arteries (PAs) and the nutrient artery (NA) of the femur. The pattern of periosteal filling and medullary perfusion of the injected dye was analysed and the topography of the PAs and NA was determined. CLPO placed the PAs and NA of the femur at risk. MIPO maintained the integrity of the PAs and NA and was associated with superior periosteal and medullary perfusion. The results of this study indicate that MIPO is superior to the CLPO in maintaining arterial femoral vascularity and perfusion.

Aged↗
PubMed1997

Minimally invasive percutaneous plate osteosynthesis (MIPPO) using the DCS in proximal and distal femoral fractures.

In a prospective study, 14 cases of supracondylar or subtrochanteric fractures or osteotomies were stabilized with a dynamic condylar screw (DCS) inserted using a minimally invasive percutaneous plate osteosynthesis (MIPPO) technique. The technique consisted of 4 major steps: 1) placement of the guide wire under fluoroscopic control and condylar screw insertion through a stab incision; 2) plate insertion beneath the vastus lateral muscle; 3) engagement of the condylar screw to the plate using a modified T-handle and, 4) plate fixation to the shaft using percutaneously inserted self-cutting screws. Between October 1994 and December 1995, 14 cases in 12 patients met the inclusion criteria. There were 11 acute fractures (6 subtrochanteric, 5 supracondylar) and 3 corrective osteotomies. Nine fractures were closed, and 2 were open. One 97-year-old patient died 6 weeks after trauma. There were no infections and 12 of 13 cases healed without a second procedure. There was 1 implant failure (plate screw breakage), which required repeat fracture fixation. At follow-up, there were 2 varus deformities above 5 degrees, 2 shortenings over 20 mm, and 1 rotational deformity of 20 degrees. According to the Neer score, there were 6 excellent, 1 satisfactory, 3 unsatisfactory results and no failures. The results of this technique compare favourably with those of other series of osteosynthesis of subtrochanteric or supracondylar femoral fractures treated with internal fixation without the added morbidity associated with an extensive approach or autogenous bone grafting. However, the surgical technique is demanding, and care must be taken to restore the axial alignment.

Adult↗
PubMed1997

Transarticular joint reconstruction and indirect plate osteosynthesis for complex distal supracondylar femoral fractures.

In a prospective study conducted between 1992 and 1995, displaced Müller type C2-C3 intraarticular fractures of the distal femur were treated using an indirect plate fixation technique and a lateral parapatellar arthrotomy for the direct reduction of the condylar block. There were 6 closed, and 2 open fractures (1 grade II and 1 grade IIIB). Following reconstruction of the articular block, the block was indirectly reduced and fixed to the shaft by a plate inserted by the retrograde method beneath the vastus lateralis. Transcutaneous/transmuscular screws were used to fix the plate to the shaft. Time to bone healing was 12 weeks (median range 8-17 weeks) after surgery without needing primary or secondary bone grafts. There were no infections or refractures. Except for one case which required a corrective osteotomy for 10 degrees of varus malalignment, there were no revisions. According to the Neer score, there were 6 excellent or satisfactory results, 2 unsatisfactory results, and no failures. At follow-up, there were 2 varus-valgus deformities greater than 5 degrees, 2 leg length discrepancies greater than 10 mm, and 2 rotational deformities of 15 degrees. The treatment results for complex supracondylar/intracondylar fractures of the distal femur obtained with this technique compare favourably with other reported series using different techniques without the added morbidity associated with autogenous bone grafting. However, the surgical technique is demanding and special care must be taken to ensure correct axial alignment.

Adult↗
PubMed1997

The deformation of small diameter solid tibial nails with unreamed intramedullary insertion.

'Radiation-independent' aiming systems for the placement of interlocking screws in intramedullary tibial nails have failed because of insertional related nail deformation. Prior to the development of these distal aiming systems, the variable position of the nails' interlocking holes after insertion must be known. In this study, the amount and direction of implant deformation of solid stainless-steel tibial nails (diameters of 8 and 9 mm, n = 20) were analyzed. Measurement of implant deflection (three translations, three angles) in the center of distal transverse locking hole was performed with a three-dimensional-magnetic motion tracker system after nail insertion in paired human cadaver tibiae. The results showed combined mean lateral translation of the 8 and 9 mm nails (n = 20) of -4.5 +/- 3.5 mm (range: 14.3 mm) and dorsal translation -7.8 +/- 5.8 mm (range: 19.2 mm). The combined mean rotational deformation about the longitudinal axis of the nail was 0.3 +/- 0.7 degree (range: 2.4 degrees). The authors conclude that a simple aiming arm, mounted on the proximal nail end alone, is not sufficient to provide accurate distal aiming.

Bone Nails↗
PubMed1997

The torsional strength of bones with residual screw holes from plates with unicortical and bicortical purchase.

OBJECTIVE: To evaluate the effect of unicortical and bicortical screw holes on residual bone strength by comparing the in vitro torsional strength of cadaveric sheep tibiae with screw holes from plates with unicortical and bicortical purchase relative to each other and to intact bone. DESIGN: The paired tibiae were grouped randomly and torsion tested to failure as follows: Group I -- unicortical screw holes versus intact bone; Group II -- bicortical screw holes versus intact bone; and Group III -- bicortical versus unicortical screw holes. BACKGROUND: Recently the point contact fixator, or PC-Fix (using screws with unicortical purchase), was designed to minimize bone devascularization beneath the plate compared to the conventional dynamic compression plate, or DCP (bicortical purchase), and possibly reduce refracture rates after plate removal. However, the effects of unicortical versus bicortical residual screw holes on potential refracture are unknown. METHODS: Screw holes were drilled and tapped through either a 7-hole bicortical DCP or a unicortical PC-Fix in 18 paired cadaveric sheep tibiae. The bones were then tested in torsion. RESULTS: The average decreases in the torsional strength of unicortical screw holes versus intact bone, bicortical screw holes versus intact bone, and bicortical versus unicortical screw holes were 21.6, 31.4, and 26.7% respectively. Mean torque values to failure were statistically significant within each of the three groups: P<0.01, 0.001, and 0.001 respectively. CONCLUSIONS: Bones with unicortical screw holes are significantly weaker in torsion than intact bones, but significantly stronger than bones with bicortical holes. RELEVANCE: Refracture after hardware removal is a recognized clinical complication of the traditional bicortical screw fixation. In combination with the demonstrated biological advantages, implants with unicortical purchase may be associated with less risk for early refracture upon removal.

Journal Article↗
PubMed1997

In vitro and in vivo radiomorphometric analyses of distal screw hole position of the solid tibial nail following insertion.

OBJECTIVE: The objective of this study was to analyse the position of the distal interlocking holes of an unreamed solid tibial nail relative to the adjacent cortices of the tibial bone. DESIGN. IN VITRO: and in vivo radiographic-morphometric analysis. BACKGROUND: To date, 'radiation-independent' intramedullary distal interlocking aiming systems have not been successful, primarily because proximally mounted aiming devices cannot account for the deformation of the nail during insertion; therefore the distal interlocking holes relative to the adjacent cortices must be understood. METHODS: A two-dimensional radiographic-morphometric analysis was performed in 40 tibiae after in vitro (n = 20) and in vivo (n = 20) implantation of unslotted stainless steel unreamed 8- and 9-mm diameter intramedullary nails. RESULTS: The combined in vitro and in vivo results showed average distances between the upper distal transverse hole and the anterior aspect of the tibia of 12.3 mm (SD 1.7 mm; variance 2.9 mm(2); range 7.6 mm). CONCLUSIONS: The distances between the upper distal transverse hole and the anterior aspect of the tibia are the most reliable parameters of distal nail hole position. RELEVANCE: For a 'radiation-independent' distal interlocking aiming system for unreamed intramedullary tibial nails to be successful, it could take advantage of the relatively constant distance between the anterior cortex and the most proximal distal screw hole.

Journal Article↗
PubMed1997

A simple technique for creating hybrid fixators using a modified AO single adjustable clamp.

Hybrid external fixators with limited internal fixation have become popular in the treatment of complex intraarticular fractures of the tibia. A wide variety of hybrid external fixation systems are commercially available, but these frames are expensive and not always readily available. The authors present a simple hybrid frame constructed from the AO tubular and Ilizarov type external fixator sets using a modified AO single adjustable clamp. This hybrid frame is easy to apply, versatile, and significantly less expensive than other commercially available adaptors and frames.

Equipment Design↗
PubMed1997

Segmental avascularity of the humeral diaphysis after reamed intramedullary nailing.

Although the clinical experience with reamed intramedullary nailing has been successful for the treatment of femur and tibia fractures, similar success has not been duplicated when this technique has been applied in the humerus. Although the cortical vascular response to nailing of the humerus is presently assumed to be similar to that of the femur, the response of the humerus to reaming has not been documented in vivo. The following case depicts avascularity of the humeral diaphyseal cortex as a complication of reamed intramedullary nailing and illustrates the sensitivity of the humerus to this treatment.

Adult↗
PubMed1997

A new technique for the distal locking of solid AO unreamed tibial nails.

Proximally mounted distal aiming systems have failed primarily because of nail deformation during insertion. A mechanical aiming device for the insertion of distal locking screws for solid unreamed AO tibial nails was developed and was tested in twenty unreamed solid tibial nailing procedures in a video-documented prospective clinical study. The rate of accurate screw placement, time expended, complications, and outcome for each patient were recorded. Distal locking was performed successfully in all cases without image intensification. Although a high percentage (55%) of fractures were open, the total mean operative time was 108 minutes (range, 60 to 180 minutes) and the mean time for distal locking (three screws) was 15.5 minutes (range, 8.0 to 39.0 minutes). Notable drill-nail contact occurred in 15 percent of the distal screws placed, demonstrating accurate aiming and drilling. There were no major intra- or postoperative complications related to the distal aiming system.

Adolescent↗
PubMed1997

Recurrent rotational deformity of the femur after static locking of intramedullary nails: case reports.

Rotational deformity following intramedullary nailing may cause symptoms and require surgical correction by osteotomy. Reamed, locked intramedullary nailing may be performed, but concern about cortical blood supply and potential pulmonary dysfunction from reaming have led many surgeons to limit this and use smaller diameter nails. Slotted nails are commonly used but are less stiff in torsion than the newer unslotted nails, particularly at the lower diameters. We report two cases of recurrent femoral rotational deformity after using statically interlocked slotted intramedullary nails to correct existing femoral rotational deformities. These patients show that small diameter statically interlocked femoral nails with diminished bone-nail contact must be stiff enough in rotation to avoid potential recurrence.

Adult↗
PubMed1996

Autogenous cancellous bone graft incorporation in a gap defect in the canine femur.

While gap defect models provide greater graft stability and are more representative of many clinical situations than segmental defect models, the healing in these models has not been well documented. To study the histologic course of cancellous bone graft healing in a long bone gap defect, 12 adult mongrel dogs were killed in groups of two at 1, 2, 3, 4, 6, and 12 weeks. Graft incorporation in these dogs was studied using macro- and microradiography, histologic sections, and computer-assisted digital surface analysis; results are described. Unlike that seen in segmental defect models, the pattern of repair in a cancellous bone grafted gap defect provides consistent healing at 12 weeks and follows the same healing process seen with stable defects.

Animals↗
PubMed1996

Accuracy of intramedullary templates in femoral and tibial radiographs.

The accuracy of templates used for the preoperative planning of the fixation of intramedullary fractures depends on radiological magnification. To study the accuracy of these templates, we randomly selected 100 femoral and 100 tibial radiographs taken after stabilisation by an intramedullary nail using a standard technique. We then compared the known nail length with the corresponding measurements on the radiographs. The mean magnification factor for the femur was 9% and for the tibia 7%; these differ considerably from the range of magnification of the manufacturers' templates (femur, 15% to 17%; tibia 10% to 15%). We conclude that templates are unreliable for the selection of implant length and that this should be done by intraoperative measurements.

Bone Nails↗