LEGION HK Dis and Re-Assembly Tech.pdf - Bonerepmedical.com

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Preoperative evaluationThe preoperative evaluation of a failedtotal knee arthroplasty begins with acomplete history and physical examination.Determination of the etiology or failurewill also require radiographic evaluation,occasionally the use of nuclear bonescans, the use of laboratory studies and/or aspiration to rule out the possibilityof indolent infection. It is imperative thatthe cause of failure be determined preoperativelyin order to help maximize thelikelihood of post-operative success.If bone defects secondary to osteolysisexist pre-operatively then the surgeonperforming the procedure must understandthe implications of this bone loss as well astechniques required to manage them. CTscans can be a valuable tool in determiningstructural defects. Gross instability orbone loss in the area of the collateralligaments may need a stabilized orconstrained prosthesis.Appropriate patella position should beassessed preoperatively and correctivestrategies developed, if needed. A need tomove the joint line distally can be a commonoccurrence in Revision TKA, and if knownpreoperatively, can save time over adjustingthe joint line after the trial range of motion.An assessment of the joint line and patellaheight should be completed preoperativelyand/or prior to the removal of any existingcomponents with any necessary correctionsnoted. The noted corrections can then beperformed within the initial steps of thesurgical technique – distal resection, A/Pblock resections and Femoral Trial.System summaryThe LEGION HK Hinge Knee System is a primarilycondylar-loading design, as opposed to an axialloadinghinged knee system. Unlike other hingedknee systems, the LEGION HK system is designedwith femoral rollback as defined by articular contact.Together, the femoral rollback and condylar loadingproduces similar wear characteristics as seenin primary TKA designs in like conditions.The LEGION HK Hinge Knee System utilizes thesame footprint for the femoral and tibial componentsfor their respective size offerings (sizes 3 through 5for the femoral components and sizes 2 through 5for the tibial components) as the LEGION RevisionSystem. However, the LEGION HK System has norestrictions on size matching; in other words, a size5 fits a size 2 in either direction.Epicondyle center2.5cm1 – 3cmPatella and joint linePatellaJoint line1.5cmFibula head2
Femoral componentThe LEGION HK femoral components are availablein sizes 3-5 in asymmetrical configurations.Bone preparation requires two variationsfrom the LEGION Revision femoral technique.The posterior resection will be made throughthe 10mm posterior wedge resection slotswhich eliminate the need for posteriorchamfer resections.The second variation is a slight differencein the intracondylar box geometry. For thisdifference, the LEGION HK system includes itsown box reamer and chisel. This preparation isthe same as the LEGION Revision System but isproduced through the LEGION HK femoral trial.Tibial componentThe LEGION HK tibial components come in sizes 2through 5 and are also asymmetrical. The primarydifference in preparation from the LEGION RevisionTibial System is the reaming depth. The LEGIONHK tibial tray is approximately 15mm longer;therefore additional reaming depth is required.Tibial wedgesThe tibial wedge offerings match the LEGIONRevision System in sizes, heights and geometries.Full wedges are in 10mm and 15mm heights andhemi-stepped wedges are in 5mm, 10mm, and15mm heights. Do note however, the tibialwedges labeled “LEGION CK/HK” are the onlyones that may be used with the LEGION HKtibial component.Femoral wedgesThe femoral wedges come in hemi, symmetricalconfigurations in distal heights of 5mm, 10mm,15mm and 20mm.Tibial insertsIn general, the insert height offerings 11mm, 13mm,15mm, 18mm and 21mm and peripherally fit twosize tibial trays – pairing are sizes 2-3 and 4-5. Theguided-motion inserts are asymmetrical (left andright).The LEGION HK guided-motion insert is a‘fixed-bearing’ design. The insert is locked to thetibial tray through a redundant locking configurationto help minimize motion between the tibial tray anddistal insert surfaces. The primary distinction of theLEGION guided-motion design and other designs isthe guided-rotation/’screw-home’ kinematics. Oneof the central points of this design was to potentiallyreduce the complication rates of patellar dislocation/subluxation. The guided-motion insert is designedto help induce normal kinematic rotation to ‘zero’ theQ-angle of the patellar/quad mechanism throughthe range of motion. When the Q-angle is reduced,the medial/lateral shear forces are reduced fromthe patella, which in turn reduces the forces fordislocation/subluxation. However, other conditionsmay still exist.StemsAll LEGION stems (straight and bowed in cementedand press-fit configurations) can be used with theLEGION HK Hinge Knee System. The only variationbetween the LEGION Revision System and theLEGION HK system is the length of the tibial traystem connection. The LEGION HK tibial tray isapproximately 15mm longer; therefore additionalreaming depth is required on the tibial preparation.All LEGION Revision Offset Couplers functionwith the LEGION HK system.3
Page 1 and 2: Surgical TechniqueHinge Disassembly
Page 6: ExposureExposure of the revision to
Page 9 and 10: There are two options for removal o
Page 11 and 12: Implant linkage assembly1. Install
Page 13 and 14: If the opposite side is accessible,
Page 15 and 16: Component assemblyTibial insert ass
Page 17 and 18: 10. Insert the Sleeve through the L
Page 19 and 20: 15. In a vertical position, use the

LEGION HK Dis and Re-Assembly Tech.pdf - Bonerepmedical.com

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