TOTAL KNEE SYSTEM Primary Surgical Technique GENESIS II Primary Surgical Technique TABLE OF CONTENTS Introduction. 2 Preop Planning . 3 Short Technique. 4 Femoral Preparation. 8 Tibial Preparation . 17 Femoral and Tibial Trialing . 22 Patellar Preparation. 24 Component Implantation. 28 Appendix. 31 Nota Bene: The technique description herein is made available to the healthcare professional to illustrate the authors’ suggested treatment for the uncomplicated procedure. In the final analysis, the preferred treatment is that which addresses the needs of the patient. INTRODUCTION T he GENESIS II Total Knee System has been The tibial instrumentation is designed to adjust for tibia designed to offer the orthopaedic surgeon solutions to variation by offering a movable medial offset at the address intraoperative situations. Implant function is ankle. Left and right tibial cutting blocks avoid impinge- directly related to accurate surgical technique. The ment with the patellar tendon and allow the surgeon to GENESIS II instrumentation has been developed to be affix the block more intimately with the anterior proxi- an easy-to-use system that will assist the surgeon in mal tibia. As determined by anatomical restrictions or obtaining accurate and reproducible knee alignment. surgeon preference, both intramedullary and The use of patent pending locking cams and quick con- extramedullary tibial alignment options are available. nects will save time and allow the surgeon to easily align While it has been the designers’ objective to develop cutting blocks and assemble instrumentation. The intra- accurate, easy-to-use instrumentation, each surgeon must operative option of anterior or posterior femoral refer- evaluate the appropriateness of the following technique encing offers the surgeon the ability to select the based on his or her medical training, experience, and femoral implant size that best fits the patient. patient evaluation. Contributing Clinicians Kurt E. Blasser, M.D. Richard S. Laskin, M.D. William B. Smith, M.D. Instructor of Orthopaedic Surgery Professor of Clinical Orthopaedic Surgery Assistant Clinical Professor in Mayo Medical School Cornell University Medical College Orthopaedic Surgery Consultant in Orthopaedics Attending Orthopaedic Surgeon Medical College of Wisconsin Mayo Clinic Jacksonville The Hospital for Special Surgery Columbia Hospital Jacksonville, Florida New York, New York Milwaukee, Wisconsin Robert B. Bourne, M.D., F.R.C.S.C. Craig G. Mohler, M.D. Mark A. Snyder, M.D. Chief of Orthopaedic Surgery Orthopaedic and Fracture Clinic of Eugene Clinical Instructor University Hospital Sacred Heart Medical Center University of Cincinnati The University of Western Ontario Eugene, Oregon Orthopaedic Surgeon London, Ontario, Canada Christ Hospital Go Omori, M.D. Cincinnati, Ohio J. Patrick Evans, M.D. Chief of Knee Service Clinical Professor of Orthopaedic Surgery Department of Orthopaedic Surgery Todd V. Swanson, M.D. University of Oklahoma Nigata University School of Medicine Desert Orthopaedic Center Chief of Staff Nigata City, Japan Las Vegas, Nevada Bone & Joint Hospital Oklahoma City, Oklahoma James A. Rand, M.D. Jan Victor, M.D. Professor of Orthopaedic Surgery Department of Orthopaedics Ramon B. Gustilo, M.D., P.A. Mayo Medical School St. Lucas Hospital Professor of Orthopaedic Surgery Consultant in Orthopaedics Brugge, Belgium University of Minnesota Mayo Clinic Scottsdale Director of Orthopaedic Learning Center Scottsdale, Arizona Hennepin County Medical Center Minneapolis, Minnesota G. Lynn Rasmussen, M.D. Clinical Instructor Steven B. Haas, M.D., MPH Department of Orthopaedics Assistant Professor of Orthopaedic Surgery University of Utah Cornell University Medical College Co-Director Total Joint Replacement Attending Orthopaedic Surgeon Orthopaedic Specialty Hospital The Hospital for Special Surgery Salt Lake City, Utah New York, New York Michael Ries, M.D. John A. L. Hart, M.B.B.S., F.R.A.C.S. Clinical Assistant Professor of Senior Lecturer, Department of Surgery Orthopaedic Surgery Monash University S.U.N.Y. Stony Brook Senior Orthopaedic Surgeon Attending Orthopaedic Surgeon Alfred Hospital The Mary Imogene Bassett Hospital Melbourne, Australia Cooperstown, New York 2 PREOP PLANNING D etermine the angle between the anatomical and Beware of misleading angles in knees with a flexion the mechanical axes. This measurement will be used contracture or rotated lower extremities. The intraoperatively to select the appropriate valgus T-template provided as part of the GENESIS II angle so that correct limb alignment is restored. templates will help in this determination. Recommended GENESIS II Sawblade: 7144-0374 3M 7144-0376 Stryker 7144-0378 Amsco-Hall 7144-0375 New Stryker or any .050” or 1.27 mm Thickness Sawblade 3 SHORT TECHNIQUE Primary Surgical Technique 1 Use the 9.5 mm femoral drill to 2 Slide the femoral valgus align 3 For anterior referencing, attach 4 For posterior referencing, attach open the femoral canal. ment assembly up the intramedullary the femoral sizing stylus to the the femoral sizing stylus to the rod until it contacts the distal femur. anterior referencing (gold color) posterior referencing (silver color) femoral sizing guide. Attach the femoral sizing guide. Attach the guide guide to the valgus alignment to the valgus alignment assembly. If assembly. If indicated size is between indicated size is between two sizes, two sizes, select the smaller size. select the larger size. 7 Remove the valgus alignment 8 Place the femoral A-P cutting 9 For extramedullary tibial align- 10 For intramedullary tibial align- assembly and distal femoral resection block onto the distal femur and secure ment, assemble the extramedullary tib- ment, place the intramedullary tibial stylus from the distal femoral cutting with angled pins through the sides of ial alignment guide and place the guide alignment assembly onto the tibia. block. Resect the distal femur. the block. Resect the femur. onto the tibia. Rotate so that it aligns Rotate so that it aligns over the over the medial third of the tibial medial third of the tibial tubercle. tubercle. 13 Select the appropriate tibial drill 14 With the 11 mm tibial collet in 15 Place femoral, tibial, and 16 Determine whether a porous or guide and place it on the proximal place, drill with the 11 mm tibial articular insert trials in position nonporous tibial implant will be used. tibia; pin in place. drill and punch with the 11 mm and perform a trial range of motion. Select the appropriate tibial fin punch tibial punch. Alignment marks on the front of the and punch through the tibial trial. trials should match up. 19 After trialing the patella, drill for 20 Implant tibial component. 21 Implant femoral component. 22 Implant articular insert. the femoral lugs through the femoral trial. Remove femoral, tibial, and patellar trials. 4 SHORT TECHNIQUE Posterior-Stabilized 5 Resect the anterior cortex. 6 Attach the distal femoral resection 1 Place the appropriate size housing stylus and cutting block to the anterior resection block on the distal femur. or posterior referencing femoral sizing Secure with 1/8" trocar pins through guide. Pin the distal cutting block to the angled holes in the sides of the the anterior cortex. block. 2 Attach the posterior-stabilized housing resection collet to the housing resection block. 11 Attach the primary tibial stylus 12 Remove the tibial alignment to the tibial cutting block. Insert pins assembly leaving the cutting block through the central holes to secure. on the anterior tibia. Resect the proximal tibia. 3 Attach the housing reamer dome to the patellar reamer shaft. Ream through the posterior-stabilized housing resection collet. Ream until the automatic depth stop contacts the collet. 17 Determine the appropriate 18 Attach patellar depth stop and diameter patellar implant. Select reamer dome to reamer shaft. Attach correct patellar reamer collet. the patellar depth gauge to the Attach the patellar reamer guide reamer guide. Lower patellar depth to the patella. stop until it contacts the depth gauge. Remove gauge. Ream the patella. 4 Impact the housing box chisel/ sizer through the posterior-stabilized housing resection collet to square off the corners of the housing. 23 Implant patellar component. 5 If the chamfer resections have not been made, they can now be made by cutting through the chamfer slots in the housing resection block. 5 FEMORAL PREPARATION STEP 1: INTRAMEDULLARY FEMORAL ALIGNMENT O bjective—Align the distal femoral resection at the correct valgus angle using the femoral canal as a reference. Figure 1 1 Use the 9.5 mm femoral drill to open the femoral canal (Figure 1). 2 Select the appropriate valgus angle bushing based upon preoperative measurements. Assemble the selected bushing to the femoral valgus alignment Figure 2 guide. Make sure the bushing is positioned so that either “left” or “right” (based on the operative knee) is facing anteriorly. When operating on the left knee, “left” should face anteriorly. When oper- ating on the right knee, “right” should face anteriorly. Attach quick Figure 3 connect handles to the valgus alignment guide, if necessary. 3 Attach the modular T-handle to the intramedullary rod. Insert the intramedullary rod through the valgus angle bushing and into the medullary canal. Slide the valgus alignment assembly up the intramedullary rod until it contacts the distal femur. The posterior paddles on the valgus alignment assembly should contact the posterior condyles (Figure 2). Note: If the posterior condyles are deficient, the femoral rotational alignment guide can be placed over the valgus angle bushing to aid in proper rotational alignment (Figure 3). Make sure that the guide is positioned so that either “left” or “right” (based on the operative knee) is facing distally. When operating on the left knee, “left” should face distally. When operating on the right knee, “right” should face distally. The valgus alignment guide can be placed in a neutral orientation by aligning the outriggers of the femoral rotational alignment guide with the epicondyles and the trochlear reference line on the distal surface of the femoral rotational alignment guide with the trochlear groove.