Safe extracapsular placement of proximal tibia transfixation pins

Knee-Spanning External Fixation for Recurrent Traumatic Anterior Prosthetic Knee Dislocation With Associated Vascular Injury

Traumatic anterior prosthetic knee dislocation after total knee arthroplasty is a rare event. We report the case of an 88-year-old female who presented with right traumatic anterior knee dislocation and concurrent popliteal artery injury requiring an emergent bypass graft. Postoperatively, the patient had redislocated her prosthetic knee, requiring urgent re-reduction and stabilization with an external fixator. We review her case, as well as additional reported cases of anterior knee dislocation. We also review the clinical considerations surrounding arterial injury, vascular bypass, and external fixation as a proposed management in unstable cases refractory to bracing.

Cadaveric analysis of capsular attachments of the distal femur related to pin and wire placement

OBJECTIVES

Septic arthritis following intra-capsular penetration of the knee by external fixation devices is a complication of traction/fixation devices inserted in the lower extremity [1,2]. The authors were unable to find reference to or exact measurements of the capsular attachments relating to the distal femur documented in the current literature. This study aimed to demonstrate the capsular attachments and reflections of the distal femur to determine safe placements of wires or traction devices.

METHODS

The attachments of the capsule to the distal femur were measured in 10 unembalmed cadaveric knees. Capsular attachments were measured anteriorly at the maximal extension of the supra-patella pouch. Medially and laterally measurements were expressed as percentages related to the maximal AP diameter of the distal femur.

RESULTS

Mean distance from the centre of the anterior part of the notch to the superior fold was 79.5mm (Range 48.1-120.7 mm). The medial capsular reflections measured in a plane from the adductor tubercle to the anterior edge of the medial femoral condyle demonstrated the capsular reflection was attached an average of 57% back from the anterior edge (Range 41-74%). Laterally the capsular reflections on a line drawn from the maximal diameter in the sagittal plane were attached an average of 48% from the anterior reference point (Range 33-57%). Measuring the reflections at 45 degrees to the long axis of the femur in the sagittal plane the attachment was an average of 51% from the anterior reference point.

CONCLUSIONS

Capsular reflections varied among specimens. Medially the capsule attachment was up to 74% of diameter of distal femur at the level of the adductor tubercle. Therefore, the insertion of distal femoral traction pins or similar should be placed proximal to the adductor tubercle and no further than 25% of the distance to the anterior cortex. Care is also needed to ensure pins do not travel to exit too anteriorly on the lateral side as capsular attachments were found to be up to a distance 48% of the diameter of the femur from anterior reference point. Distal condylar extra-articular fixation with Schanz screws is feasible if orientated in the oblique plane.

Intra-articular Placement of an Intraosseous Catheter

Gaining vascular access is essential in the resuscitation of critically ill patients. Intraosseous (IO) placement is a fundamentally important alternative to intravenous (IV) access in conditions where IV access delays resuscitation or is not possible. This case report presents a previously unreported example of prehospital misplacement of an IO catheter into the intra-articular space of the knee joint. This report serves to inform civilian and military first responders, as well as emergency medicine physicians, of intra-articular IO line placement as a potential complication of IO vascular access. Infusion of large amounts of fluid into the joint space could damage the joint and be catastrophic to a patient who needs immediate IV fluids or medications. In addition, intra-articular IO placement could result in septic arthritis of the knee.

Treatment of bicondylar tibia plateau fractures using locked plating versus external fixation

Bicondylar tibial plateau fractures can be difficult to treat due to the extent of articular cartilage, metaphyseal bone, and soft tissue injury. The purpose of this study was to compare the outcomes of open reduction and locked plating vs fine-wire external fixation of 58 consecutive bicondylar tibial plateau fractures at a level I trauma center. All bicondylar tibial plateau fractures were classified as Schatzker V/VI or AO/OTA type 41C. Twenty-eight patients in one group were treated using a locked plating system, and 30 patients in another group were treated with a hybrid or circular external fixation frame. The 2 groups were similar demographically. When compared with external fixation, locked plating was associated with a decreased time to union (5.9 vs 7.4 months), decreased incidence of articular malunion (7% vs 40%; P=.003), decreased knee stiffness (4% vs 13%), and decreased overall complications (27% vs 48%). The Schatzker VI subgroup accounted for 25 of the 27 complications (93%) in the locked plating group and 40 of the 48 complications (83%) in the external fixation group. We reserve the use of external fixation devices in the treatment of tibial plateau fractures to span the fracture site until the patient is amenable to definitive fixation with locked plating.