Minimally Invasive TKA PROFIX Distal Cut First

Transcription

1 Surgical Technique INNOVATIONS IN MINIMALLY INVASIVE JOINT SURGERY Minimally Invasive TKA PROFIX Distal Cut First

2 Instruments Femoral Sizing Guide Femoral Anterior Referencing Stylus Femoral Sizing Stylus Paddle Alignment Guide Valgus Alignment Guide Right Left External Rotation Paddle Left Right Neutral Valgus Collet 5 Valgus 0 Flex Collet Valgus 4 Flex Collet (Right) Valgus 4 Flex Collet (Left) Distal Resection Stylus Left Right Distal Resection Block Tibial Cutting Block (Left) Tibial Cutting Block (Right) Femoral Cutting Block Size Size Size Size Size Size Size Quick Release Handle Minimally Invasive Instrument Tray Minimally Invasive Cutting Block Tray

3 Instruments IFC Introduction Leg Position Incision Arthrotomy Exposure Femoral Preparation , 4, 5, 6 Sizing Distal Cutting Assembly and Resection Femoral Resection Anterior Referencing Femoral Resection Posterior Referencing Tibial Preparation , 8 Intramedullary Tibial Alignment and Proximal Tibial Resection Extramedullary Tibial Alignment and Proximal Tibial Resection Tibial and Femoral Preparation Knee Alignment Assessment Patellar Preparation , 12 Inset Technique Onset Technique Posterior Stablized , 14 Implantation , 16 Tibial Implantation Femoral Implantation Patellar Implantation Closure Leo A. Whiteside, M.D. Missouri Bone & Joint Center St. Louis, MO Nota Bene: The technique description herein is made available to the healthcare professional to illustrate the author s suggested treatment for the uncomplicated procedure. In the final analysis, the preferred treatment is that which addresses the needs of the patient. 1

4 Introduction Leg Position Appropriate leg position is crucial when performing minimally invasive total knee arthroplasty. During the procedure, the knee is flexed to Hyperflexion is used only intermittently for specific portions of the case, such as insertion of the tibial component. To aid in holding the leg, a sandbag is placed across from the contralateral ankle when positioning the patient on the table. Incision With the leg fully extended, a longitudinal incision measuring 9.5 to 12 centimeters (3 3 /4 to 4 3 /4 inches) is made over the anterior aspect of the knee along the medial border of the patella. The incision extends approximately from the middle of the tibial tubercle to a point slightly proximal to the superior pole of the patella. If significant tension is noted at the skin edges, the incision should be extended to minimize risk of wound edge necrosis. Arthrotomy The procedure can be performed using a minipatellar capsulotomy or a mini-midvastus capsulotomy. The midvastus may offer some advantages for quicker recovery of extensor function postoperatively. However, in cases where the extensor mechanism is stiff or the patient is heavily muscled, the parapatellar capsulotomy may allow easier mobilization of the patella. Either type of arthrotomy can be extended to conventional length if exposure is problematic. For the mini midvastus approach, begin 5mm medial to the tibial tubercle and extend dissection around the medial border of the patella. The arthrotomy is extended up to the proximal border of the patella. The suprapatellar pouch is identified, separated from the underside of the tendon and preserved. The distal extent of the vastus medialis (VMO) is identified and the orientation of the fibers is determined. An oblique cut is made to the VMO and the muscle fibers are then spread bluntly for approximately 2cm (Figure 1). Exposure With the leg extended, the patella is retracted laterally. The fat pad is excised both medially and laterally leaving a small amount of fat deep under the patellar tendon. The patellar tendon proximal to the tubercle is dissected from the tibia. At this point, release of the anterior horn of the lateral meniscus will facilitate reflection of the mechanism to the lateral side. The anterior horn of the medial meniscus is divided and dissection is carried around the proximal medial tibia using electrocautery and a box osteotome. A thin bent Hohmann is placed into the lateral side to hold the patella in a subluxed position while a second Hohmann or a Z-retractor is placed along the medial border of the proximal tibia to protect the medial collateral ligament (Figure 2). Tip: Excessive tension on the retractors is not necessary and can sometimes hamper the exposure. The proximal soft tissue attachments extending around the proximal medial tibia are released in the standard fashion. Finally, divide and excise the anterior cruciate ligament if present. Tip: In patients with a tight extensor mechanism (usually larger, muscular patients or those with abundant patellar osteophytes), the patella is cut at this time (see page 11). 2 Figure 1 Figure 2

5 Femoral Preparation Sizing 1. Flex the knee Place a thin bent Hohmann retractor laterally around the tibia and retract the patella laterally (not everted). 3. Divide and excise the ACL and the anterior horn of the lateral meniscus. 4. Identify the rotational reference landmarks A-P axis (Whiteside's Line) Medial/lateral posterior femoral condyles Epicondylar axis. 5. Using the Femoral 3/8" Drill, make a hole anterior to the posterior cruciate ligament attachment. This drill is easily attached to power equipment using the Power Quick Connect. The resulting starter hole is larger than the 8mm Reamer Rod. Aspirate the canal thoroughly with a long suction cannula. 6. Attach the T-Handle Quick Connect to the 8mm Reamer Rod and slowly insert into the femoral canal. 7. Set the Femoral Sizing Guide for the correct knee (left or right). If operating on a left knee, the left paddle should be placed posteriorly so that the lines on the paddle and on the body of the sizer are even. The opposite paddle should be placed anterior (Figure 3). Lock the paddles into place with a Hex Screwdriver or thumbscrews. Place the Femoral Sizing Stylus in the Femoral Sizing Guide on what will correlate with the medial side of the knee (on the side of the left paddle if operating on a left knee) (Figure 4). 8. Place the Femoral Sizing Guide over the 8mm Reamer Rod, assuring that the paddles are fully engaged with the posterior femoral condyles (Figure 5). Place the stylus tip proximal and lateral to the anterior femoral sulcus. Read the appropriate femoral component size. If in between sizes, select the smaller size for anterior referencing and the larger size for posterior referencing. Figure 3 Figure 4 Figure Femoral 3/8" Drill Power Quick Connect T-Handle Quick Connect mm Reamer Rod Hex Screwdriver 3

6 Femoral Preparation (Continued) Distal Cutting Assembly and Resection 1. Assemble the Valgus Alignment Guide (Left or Right) and the 5 Valgus 0 Flex Collet. Slide the collet into the open ended U-shaped slot of the Valgus Alignment Guide (Figure 6). Lock the Valgus Collet with the thumbscrew or Hex Screwdriver. Figure 8 Figure 9 Figure 6 Tip: If doing the Optimizing Flexion technique, select the appropriate (Left or Right) 5 Valgus 4 Flex Collet instead of the 5 Valgus 0 Flex Collet. 2. Insert the Distal Resection Stylus (Left or Right) into the Valgus Alignment Guide with the graduations on the Distal Resection Stylus facing anterior. Using the Hex Screwdriver, lock the stylus in a slightly anterior position (Figure 7). 4. Place the Distal Cutting Assembly (Figure 9) over the IM Rod until the Valgus Alignment Guide contacts the distal femur. 5. Loosen the Distal Resection Stylus screw and slide the stylus posteriorly until it contacts the anterior femur. Re-tighten with the Hex Screwdriver. 6. Align the Distal Cutting Assembly with the A-P axis of the femur (Whiteside's Line) and pin the Distal Resection Block through the holes labeled 0mm. Pin the oblique hole if extra stability is required (Figure 10). Resect the distal femur. 7. Remove the Distal Cutting Assembly. Figure 7 3. Slide the Distal Resection Block over the Distal Resection Stylus from the back and then slide the block forward until aligned with the appropriate size mark as determined in Step 8 on page 3 (Figure 8). Lock the distal block into place with the Hex Screwdriver. Figure 10 4

7 Femoral Preparation (Continued) Femoral Resection - Anterior Referencing 1. Choose the correct size Femoral Cutting Block. 2. Attach the Femoral Anterior Referencing Stylus to the appropriate Femoral Cutting Block (Figure 11). Tip: External Rotation Paddles may be used for rotational alignment of the Femoral Cutting Block, if desired. Secure the Paddle Alignment Guide to the Femoral Cutting Block using the thumbscrew or Hex Screwdriver (Figure 13). Attach the External Rotation Paddle to the Paddle Alignment Guide leaving it free to move A-P by leaving the thumbscrew loose (Figures 14 and 15). 4. Pin the Femoral Cutting Block to the distal femur through the attachment holes on the medial and lateral sides of the cutting block. 5. Perform the femoral resections as follows: (1) Posterior, (2) Posterior Chamfer, (3) Anterior, and (4) Anterior Chamfer. Figure Place the Femoral Cutting Block on the distal femur (Figure 12). Allow the stylus to rest proximal and lateral to the anterior femoral sulcus. The block should be rotated so that the central A-P axis lines up with Whiteside's Line on the femur. Tip: If doing the Optimizing Flexion technique, align the appropriate sizing mark on the stylus arm with the back of the Femoral Anterior Referencing Stylus before locking into place. Figure 12 5

8 Femoral Preparation (Continued) Femoral Resection - Posterior Referencing 1. Choose the correct size Femoral Cutting Block. 2. Attach the Paddle Alignment Guide into the appropriate Femoral Cutting Block (Figure 13). Lock the Paddle Alignment Guide into place with the thumbscrew or a Hex Screwdriver. 4. Place the Femoral Cutting Block on the distal femur, assuring contact between the External Rotation Paddle and the posterior femoral condyles (Figure 16). Figure Place the External Rotation Paddle (Right, Left or Neutral) over the free end of the Paddle Alignment Guide. Move the External Rotation Paddle anteriorly until the bearings engage in the groove on the Paddle Alignment Guide (Figures 14 and 15). Lock the External Rotation Guide into place with the thumbscrew or a Hex Screwdriver. Figure 14 Figure 15 Tip: If doing the Optimizing Flexion Technique, follow the arrow (pointing anteriorly and marked 4º Flexion ) on the side of the Paddle Alignment Guide and move the External Rotation Paddle anteriorly until the paddle is flush with the bottom of the Femoral Cutting Block. Lock the External Rotation Guide into place with the thumbscrew or a Hex Screwdriver. Figure Use the Femoral Anterior Referencing Stylus to check anterior position to avoid notching. If notching is evident, select a larger size cutting block or loosen paddles to allow the block to slide anterior to prevent notching. 6. Pin the Femoral Cutting Block to the distal femur through the attachment holes on the medial and lateral sides of the cutting block. 7. Remove the External Rotation Paddle and Paddle Alignment Guide by loosening the thumbscrew on the Paddle Alignment Guide. 8. Perform the femoral resections as follows: (1) Posterior, (2) Posterior Chamfer, (3) Anterior, and (4) Anterior Chamfer. Tip: Downsizing Procedure: If downsizing is required after completion of the femoral cuts, align the anterior slot on the Femoral Cutting Block of the next size down to the level of the previous anterior cut (a blade can be inserted through the anterior slot and the blade can rest on the anterior cut). Pin the Femoral Cutting Block. Redo the Posterior, Posterior Chamfer and Anterior Chamfer cuts. 6

9 Tibial Preparation Extramedullary or intramedullary alignment guides may be used. A thin bent Hohmann or a Z-retractor is placed around the proximal medial tibia to protect the MCL. A thin bent Hohmann is placed over the lateral tibial plateau to retract the patella, and protect the patellar tendon. A PCL retractor or standard Hohmann may be placed posterior to the tibia to sublux the tibia anteriorly, if needed. The meniscus may be removed at this time, if desired. Osteophytes are removed from the anteromedial and medial tibia. Intramedullary Tibial Alignment and Proximal Tibial Resection 1. Using the Femoral 3/8" Drill, open the proximal tibial medullary canal just posterior to the tibial attachment of the anterior cruciate ligament. Slowly place the 8mm Reamer Rod into the tibial shaft using the T-Handle Quick Connect. Tip: To assure proper positioning of the drill hole, a Tibial Prep Plate may be used as a template to determine the appropriate location of a stem extension. Mark the center hole of the prep plate. This will approximate the stem extension location, which is slightly medial on the final tibial implant. 2. Attach the appropriate (Left or Right) Tibial Cutting Block (0 or 4 ) to the tibial stylus on the Tibial Alignment Assembly. Set the desired resection level by adjusting the Tibial Stylus on the Tibial Alignment Assembly. Usually, 8-10mm of bone is resected referencing from the unaffected side of the tibial plateau. The assembly is now placed over the 8mm Reamer Rod. Tip: If using the Optimizing Flexion Technique, select the 7 tibial block, if desired. 3. Lower the assembly until the stylus touches the most central point of the highest or "good" side of the tibial plateau. Tighten the screw against the 8mm Reamer Rod. Move the Tibial Cutting Block until it contacts the anterior tibial cortex. The sliding screw is then tightened. 4. The Tibial Cutting Block is now in the proper location to remove the desired amount of bone established in Step 2. Pin the Cutting Block to the bone using three pins (Figure 17). Remove the Reamer Rod and Tibial Alignment Assembly, if desired. 5. Resect the proximal tibia through the slotted block using a PROFIX Sawblade. 6. To get a precise tibial cut surface for press-fit applications, resect through the slot several times until the tibial surface is very flat and smooth. Figure Femoral 3/8" Drill mm Reamer Rod T-Handle Quick Connect Tibial Alignment Assembly 7

10 Tibial Preparation (Continued) Extramedullary Tibial Alignment and Proximal Tibial Resection 1. The EM Alignment Spike is impacted into the tibial spine just posterior to the anterior cruciate ligament insertion point. Place the entire assembly over the EM Alignment Spike and around the ankle to secure in place (Figure 18). Figure Attach the appropriate (Left or Right) Tibial Cutting Block (0 or 4 ) to the tibial stylus on the Tibial Alignment Assembly. Set the desired resection level by adjusting the tibial stylus on the Tibial Alignment Assembly. Usually, 8-10mm of bone is resected referencing the unaffected side of the tibial plateau. The Assembly is now placed over the EM Alignment Spike (Figure 19). 3. Lower the assembly until the stylus touches the most central point of the highest or "good" side of the tibial plateau. Move the Tibial Cutting Block until it contacts the anterior tibial cortex. The sliding screw is then tightened. Figure The Tibial Cutting Block is now in the proper location to remove the desired amount of bone established in Step 2. Pin the cutting block to the bone using three pins. Remove the EM Spike and Tibial Alignment Assembly, if desired. 5. Resect the proximal tibia through the slotted block using a PROFIX sawblade. 6. To get a precise tibial cut surface for press-fit applications, resect through the slot several times until the tibial surface is very flat and smooth EM Alignment Spike Tibial Alignment Assembly Ankle Clamp Alignment Sleeve

11 Tibial and Femoral Preparation The Tibial Prep Plate and desired Articular Insert Trial are placed on the proximal tibia to determine coverage and necessary thickness of insert to restore the joint line. The Femoral Trial is placed on the distal femur. 1. Place the Tibial Prep Plate on the proximal tibia. Place the 12mm Stem Plug into the central hole of the Prep Plate and tap into position (Figure 20). This will serve as a rotational axis. The Stem Plug can be removed from the Prep Plate with the Quick Release Handle. Figure Place the appropriate size Femoral Trial onto the distal femur and determine correct medial/lateral coverage (Figure 22). Spike the Femoral Trial into place through the distal condyles using short Bone Spikes. Figure 20 Tip: If trialing with a tibial long stem trial is desired, ream up to an odd size reamer. The Trial Taper Stem is attached to the Tibial Prep Plate for stem trial attachment. Thread the Stem Coupler (Neutral or 4 ) into desired long stem trial and impact onto the Trial Taper Stem. 2. Place the Conforming or Conforming Plus Articular Insert Trial onto the Prep Plate using the Articular Insert Trial Rotation Handle (Figure 21). Figure Using a PROFIX Sawblade, resect the patellofemoral groove, cutting along the medial and lateral sides of the Femoral Trial (Figure 23). Maintain blade contact against the Femoral Trial to assure proper resection. Insert the proper size Patellofemoral Groove Trial. Figure Tibial Prep Plate Size 4 Left mm Stem Plug Quick Release Handle Trial Taper Stem Stem Coupler Articular Insert Trial Size 4 Left 10mm Articular Insert Trial Rotation Handle Femoral Trial Size 4 Left 9

12 Knee Alignment Assessment Alignment of the knee is assessed with the femoral and tibial trials in place. The Tibial Prep Plate is rotated to assure that the line on the insert matches with the line on the Patellofemoral Groove Trial with the knee in full extension. 1. In full extension, assess the alignment of trials and evaluate range of motion. 2. Insert the Articular Insert Trial Rotation Handle into the anterior slot on the Articular Insert Trial. Rotate the handle until the lines on the Femoral and Tibial Trials are perfectly aligned (Figure 24). Prep Plate from shifting while using the punch, it is recommended to pin the Prep Plate in place through the anterior spike holes. If using the I-beam stem, use the appropriate size Nonporous Tibial Fin Punch, then remove the prep plate. Place the I-beam stem punch on the proximal tibia by inserting the fins of the punch into the prepared fin slots, then punch. Tip: The Tibial Keel Stem Punch is designed to be used with PROFIX Tibial Implants sizes 3-7. When using a Size 1 or 2 PROFIX Tibial Implant, it is recommended to use the 14mm Metaphyseal Stem. Figure With the knee in full extension, align the marks on the Insert Trial and Femoral Trial to assure proper rotational alignment. Using a cautery pencil, mark the tibia below the alignment markers on the Tibial Prep Plate. When using a Nonporous Tibial Implant, remove the Articular Insert Trial and prepare for the distal fins on the implant using the appropriate Nonporous Tibial Fin Punch, All-Poly Tibial Fin Punch, or Tibial Keel Stem Punch (Figure 25). To prevent the Figure Patellofemoral Groove Trial Size Nonporous Tibial Fin Punch Size All-Poly Tibial Fin Punch Tibial Keel Stem Punch

13 Patellar Preparation The inset patellar reaming includes the Patellar Clamp, Ring Gauge, Reamer, Reamer Collet, and Reamer Stop. Inset patellas are 23, 26 and 29mm in diameter. Thicknesses are 11, 12 and 14mm, respectively. The onset patellas are available in 29, 32, 35 and 39mm diameters. The onset technique includes the Patellar Peg Drill, Drill Guide and Patellar Clamp. Inset Technique 1. Place the Patellar Ring Gauge against the patellar surface to determine appropriate diameter (Figure 26). Slide the correct diameter Patellar Reamer Collet over the Patellar Clamp. Position the Reamer Collet over the vertical ridge of the patella and tighten the thumb screw (Figure 27). Lightly tap the proximal (top) edge of the collet with the mallet to engage the teeth of the collet into the patella. Tighten the thumb screw another half turn. Repeatedly tap and tighten until the grip is secure. Figure 26 Figure Patellar Ring Gauge Patellar Reamer Collet 26mm Patellar Clamp 11

14 Patellar Preparation (Continued) Inset Technique (Continued) 2. Place the appropriate diameter Patellar Reamer into the collet. Slide the appropriate diameter of the Ring Gauge onto the shaft of the Patellar Reamer above the Reamer Collet and lower the Reamer Stop on top of the Ring Gauge (Figures 28 and 29). Onset Technique 1. Clamp the patella on the outermost regions of the bone. Using a PROFIX Sawblade, resect the patellar bone. 2. Using the Patellar Drill Guide and the Peg Drill, drill three holes in the remaining patellar bone (Figure 31). Figure 28 Figure 29 Figure 31 Tip: The word UP should be visible on the reamer stop. 3. Remove the Ring Gauge and ream the patella until the Reamer Stop contacts the Reamer Collet. 4. Place appropriate diameter Patellar Trial into prepared bone cavity (Figure 30). Begin range of motion to evaluate patellar tracking. Remove the Patellofemoral Groove Trial using the Femoral Extractor. 3. Place the Onset Patellar Trial onto resurfaced patella and begin range of motion to evaluate patellar tracking. Remove the Femoral Trial using the Femoral Extractor. Tip: Soft tissue and ligament balancing should be checked at this point to assure appropriate alignment and stability of the joint. Figure Patellar Reamer 26mm Reamer Stop Patellar Trial 26 mm Femoral Extractor

15 Posterior Stabilized This portion of the technique will prepare the femur for the femoral housing of the PS implant. Instruments required for this procedure include the PS Positioner, PS Box Reamer Guide, PS Box Reamer, PS Box Chisel Guide, PS Box Chisel, and the PS Femoral Trial. 1. Make all femoral and tibial cuts in the manner described on pages Place the appropriate size Femoral Trial onto the distal femur and determine correct medial/lateral coverage. Spike Femoral Trial into place through distal condyles using short Bone Spikes. Using a PROFIX Sawblade, resect the patellofemoral groove, cutting along the medial and lateral sides of the Femoral Trial. Maintain blade contact against the Femoral Trial to assure proper resection. Then remove the Femoral Trial. 3. Attach the PS Positioner (Figure 32) referencing off the femoral spike holes (which were already created by the Femoral Trial) or use the Anterior Chamfer and distal cut intersection. Predrill and pin the PS Positioner with bone spikes. 4. With the thumb screws on the PS Positioner loose, place the PS Box Reamer Guide (Figure 33) into the Positioner, then tighten the thumb screw to firmly hold the Reamer Guide in place. Proceed to ream through both holes with the PS Box Reamer (Figure 34). This will prepare the majority of the femoral housing area. Figure 33 Figure Loosen the positioner thumb screw and remove the Reamer Guide. Place the PS Box Chisel Guide into the Positioner and tighten the thumb screw firmly to hold the Chisel Guide in place. Attach the Fin Punch Handle to the PS Box Chisel and impact the PS Box Chisel (Figure 35) through the Box Chisel Guide. This will complete the bone resection for the PS femoral housing. Figure 32 Figure 35 Note: If desired, the Quick Release Handle may be attached to the PS Positioner PS Positioner PS Box Reamer Guide PS Box Reamer PS Box Chisel Guide Fin Punch Handle PS Box Chisel 13

16 Posterior Stabilized (Continued) 6. Remove the positioner and assemble the PS Femoral Trial. Place the Primary Femoral Trial Module (without taper) into the appropriate size trial and tighten one of the module lugs with an implant screwdriver. After one turn, tighten the other lug one turn, and alternate until the module is seated in the trial (Figure 36). Place the PS Femoral Trial onto the distal femur (Figure 37). Do not directly impact the trial on the anteromedial or anterolateral flanges. Impacting these areas could deform the anterior cutting slots. Figure After evaluating the range of motion with Femoral and Tibial Trials, implant the PS Femoral Implant in the distal femur. Implant the Tibial and the PS Articular Insert. Assess range of motion for the final implants (Figure 38). Figure 37 Figure PS Femoral Trial Primary Femoral Trial Module without Taper

17 Implantation Tibial Implantation* Once removed from the packaging material, the PROFIX Tibial Implant is placed on the table. If a stem extension is desired, the stem should be removed from its packaging, the keyed marks on the stem aligned with the marks on the taper of the tibial implant, and impacted onto the tibial implant. Firmly impact the stem several times to assure a rigid lock of the morse taper. Note: The author recommends the use of the Metaphyseal Stem on the Porous or Nonporous Tibial Implants. Alternate Primary Tibial Stems are available. 1. Using the Tibial Rotation Alignment Guide, position the implant so the cautery markings are aligned with the markings on the tibial implant (Figure 39). Slowly force the tibial implant with the Metaphyseal Stem (or other primary stem extension) into the proximal tibia. Remove the Alignment Guide once the tibial stem has established alignment. Figure Using the Tibial Impactor, seat the tibial implant on the proximal tibia. If using screws, orient the Tibial Screw Drill Guide over each hole and drill using the Tibial Screw Drill (Figure 40). The three peripheral holes in the drill guide are angled at 10 to reach the cortex if desired (each hole is angled toward the center of the drill guide). 3. Using the Depth Gauge, determine the depth of each screw hole to accept the appropriate size screw. Insert and tighten screws of the tibial implant, alternating to avoid liftoff. 4. After determining the thickness of the articular insert, slide the insert posteriorly into the tibial implant and engage the peripheral locking mechanism. A light tap is all that should be required to seat the insert securely (Figure 41). Figure 39 Tip: If the Metaphyseal Stem is desired, the 12mm Stem Plug is the only preparation necessary to accept the Metaphyseal Stem. It is important to assure the markings align to avoid malpositioning of the tibial implant. Figure Tibial Rotation Alignment Guide Metaphyseal Stem Tibial Impactor Tibial Screw Drill Guide Tibial Screw Drill Depth Gauge 15

18 Implantation (Continued) *Cementing Technique Using the standard mixing protocol for bone cement, mix and prepare bone cement for cementing the tibial component. Irrigate the bone surface with pulse lavage and drill scleratic areas with a 1/8" drill bit to a depth of approximately 1/8". Press cement into the bone surfaces. Place bone cement on the undersurface of the tibial component and impact the tibial component into place. Remove excess cement. Using the standard mixing protocol for bone cement, apply bone cement to the undersurface of the femoral component. Compact the femoral component into place. Remove excess cement. Femoral Implantation Prior to applying cement to the femoral component, use the Femoral Peg Drill to prepare for Femoral Pegs (Figure 42). Drill to the depth of the circular groove on the peg drill. Irrigate the bone surface with pulse lavage and drill scleratic areas with a 1/8" drill bit to a depth of approximately 1/8". Press cement into the bone surfaces. Apply cement to the femoral component and place on the distal femur. Locate the peg holes, and impact into place using the Femoral Impactor (Figure 43). It is recommended to place the knee at 90 of flexion and use the articular insert to help guide the femoral component onto the femur. Patellar Implantation The PROFIX Patellar Implant is available in both inset and onset designs. Cement is used in both cases to affix the Patellar Implant to the bone. Irrigate the bone surface with pulse lavage and drill scleratic areas with a 1/8" drill bit to a depth of approximately 1/8". Press cement into the bone surfaces. 1. Apply bone cement to the undersurface of the Patellar Implant. 2. Place the Patellar Implant in the resected bone. The Patellar Cement Clamp Fitting inserted into the 23mm Patellar Reamer Collet, will be used when cementing the 23, 26 and 29mm Inset Patellar Implants. Trim excess osteophytes. Closure Closure is performed in the usual manner. Figure 43 Figure Femoral Peg Drill Femoral Impactor Patellar Cement Clamp Fitting Patellar Reamer Collet 23 mm

19 IMPORTANT MEDICAL INFORMATION Smith & Nephew Knee System DESCRIPTION OF SYSTEM Smith & Nephew Knee Systems consist of femoral components, tibial components, and accessories. The component material is provided on the outside carton label. Femoral and tibial components are available in porous and non-porous options. Non-porous components, PROFIX porous coated no-hole tibial bases and porous plus hydroxylapatite (HA) coated no-hole tibial bases are to be used with cement. Semi-constrained porous coated devices, porous plus HA coated devices and HA coated devices of the PROFIX Total Knee System and GENESIS II Total Knee System may be used without cement. Constrained tibial inserts may only be used with cemented fermoral and cemented tibial components. Hydroylapatite (HA) coatings include HA that is supplied either on a grit blasted or porous surface. Each total knee system is designed as a system and does not allow the substitution of components from other systems or manufacturers. All implantable devices are designed for single use only. Some of the alloys needed to produce orthopedic implants contain some metallic components that may be carcinogenic in tissue cultures or intact organism under very unique circumstances. Questions have been raised in the scientific literature as to whether or not these alloys may be carcinogenic in implant recipients. Studies conducted to evaluate this issue have not identified convincing evidence of such phenomenon, in spite of the millions of implants in use. INDICATIONS, CONTRAINDICATIONS, AND ADVERSE EFFECTS The general principles of good patient selection and sound surgical judgment apply to the total knee procedure. Preoperative planning and meticulous surgical technique are essential to achieve optimum results. Considerations of anatomic loading, soft-tissue condition, and component placement are critical to minimize a variety of postoperative complications. Indications for Total Knee Replacement 1. Rheumatoid arthritis. 2. Post-traumatic arthritis, osteoarthritis, or degenerative arthritis in older patients whose age, weight, and activity level are compatible with an adequate long-term result. 3. Failed osteotomies, unicompartmental replacement, or total knee replacement. 4. Posterior stabilized knee systems are designed for use in patients in primary and revision surgery, where the anterior and posterior cruciate ligaments are incompetent and the collateral ligaments remain intact. 5. Constrained knee systems are designed for use in patients in primary and revision surgery, where the posterior cruciate ligament and one or both of the collateral ligaments (i.e. medial collateral and/or lateral collateral ligament) are absent or incompetent. Contraindications for Total Knee Replacement 1. Cases where there is poor bone stock which would make the procedure unjustifiable 2. Active, local infection or previous intra-articular infections 3. Mental or neurologic conditions that tend to pre-empt the patient s ability or willingness to restrict activities 4. Neuropathic (Charcot) joint 5. Conditions that tend to place increased loads on implants such as age, weight, and activity level, which are incompatible with a satisfactory long-term result 6. Collateral ligament insufficiency (except in cases where a constrained knee system is indicated and used) 7. Skeletal immaturity 8. Use of a supracondylar nail through intercondylar notch of Profix primary femoral components 9. Use of slotted femoral and tibial stems without adequate bone support. Indications for Unicompartmental Knee Replacement 1. Noninflammatory degenerative joint disease including osteoarthritis, traumatic arthritis, or avascular necrosis; 2. Correction of functional deformity 3. Revision procedures where other treatments or devices have failed; and 4. Treatment of fractures that are unmanageable using other techniques. Contraindications for Unicompartmental Knee Replacement The contraindications for Unicompartmental Knee Replacement include all of the contraindications listed for Total Knee Replacement. Possible Adverse Effects 1. Wear of the polyethylene articulating surfaces of knee replacement components has been reported following total knee replacement. Higher rates of wear may be initiated by particles of cement, metal, or other debris which can cause abrasion of the articulating surfaces. Higher rates of wear may shorten the useful life of the prosthesis, and lead to early revision surgery to replace the worn prosthetic components. 2. With all joint replacements, asymptomatic, localized, progressive bone resorption (osteolysis) may occur around the prosthetic components as a consequence of foreign-body reaction to particulate wear debris. Particles are generated by interaction between components, as well as between the components and bone, primarily through wear mechanisms of adhesion, abrasion, and fatigue. Secondarily, particles may also be generated by third-body wear. Osteolysis can lead to future complications necessitating the removal and replacement of prosthetic components. 3. Loosening, bending, cracking, or fracture of implant components. Fracture of the implant can occur as a result of trauma, strenuous activity, improper alignment, or duration of service. 4. Dislocation, subluxation, excessive rotation, flexion contracture, decreased range of motion, lengthening or shortening of the leg, looseness of components, unusual stress concentrations, and extraneous bone can result from trauma, improper implant selection, improper implant positioning, improper fixation, and/or migration of the components. Muscle and fibrous tissue laxity can also contribute to these conditions. 5. Tibia, femur, or patella fractures. 6. Acute post-surgical wound infection, late deep wound sepsis and/or low-grade synovitis. 7. Peripheral neuropathies have been reported following total joint surgery. Subclinical nerve damage has been reported, and may be a result of surgical trauma. Temporary or permanent nerve damage can result in pain or numbness of the affected limb. 8. Wound hematoma, thromboembolic diseases including venous thrombosis, pulmonary embolus, or myocardial infarction. 9. Myositis ossificans. Periarticular calcification or ossification, with or without impediment to joint mobility. Periarticular calcification can cause decreased range of motion. 10. Skin sloughs or delayed wound healing. 11. Although rare, metal sensitivity or allergic reactions in patients following joint replacement have been reported. Implantation of foreign material in tissues can result in histological reactions involving macrophages and fibroblasts. 12. Damage to blood vessels. 13. Varus-valgus deformity. 14. Failure of the porous coating/substrate interface or hydroxylapatite coating/porous coating bonding may result in bead/ha separation. WARNINGS AND PRECAUTIONS The patient should be warned of surgical risks, and made aware of possible adverse effects. The patient should be warned that the device does not replace normal healthy bone, and that the implant can break or become damaged as a result of strenuous activity or trauma, and has a finite expected service life and may need to be replaced in the future. Preoperative 1. Use care in handling and storing of implant components. Cutting, bending, or scratching the surfaces of components can significantly reduce the strength, fatigue resistance and/or wear characteristics of the implant system. These in turn may induce internal stresses that are not obvious to the eye and may lead to fracture of the component. Do not allow the porous surfaces to come in contact with cloth or other fiber releasing materials. 2. Surgical information is available upon request. The surgeon should be familiar with the technique. 3. An adequate inventory of implant sizes should be available at the time of surgery. 4. Intraoperative fracture or breaking of instruments can occur. Instruments which have experienced extensive use or excessive force are susceptible to fracture. Instruments should be examined for wear and damage prior to surgery. 5. If a computer assisted surgery system is used, consult the applicable software and hardware reference manuals provided by the manufacturer to ensure proper operation of this equipment. Intraoperative 1. The correct selection of the implant is extremely important. The appropriate type and size should be selected for patients with consideration of anatomical and biomechanical factors such as patient age and activity levels, weight, bone and muscle conditions, etc. Generally, the largest cross-section component which will allow adequate bone support to be maintained is preferred. Failure to use the optimum size component may result in loosening, bending, cracking, or fracture of the component and/or bone. 2. Modular components must be assembled securely to prevent disassociation. Avoid repeated assembly and disassembly of the modular components which could compromise a critical locking action of the components. Surgical debris must be cleaned from components before assembly. Debris inhibits the proper fit and locking of modular components which may lead to early failure of the procedure. 3. Care is to be taken to assure complete support of all parts of the device embedded in bone cement to prevent stress concentration which may lead to failure of the procedure. During curing of cement, care should be taken to prevent movement of the implant components. 4. Fixation screws, when used, should be fully seated to assure stable fixation, and to avoid interference with the proper seating of components. Use only screws recommended by the manufacturer for the specific prosthesis to avoid improper fit, and to avoid improper mixing of metals. 5. Prior to closure, the surgical site should be thoroughly cleaned of bone chips, extraneous cement, ectopic bone, etc. Foreign particles at the metal and/or plastic interface may cause excessive wear and/or friction. 6. Posterior stabilized knee systems, constrained knee systems, and systems with a deep articular surface should not be utilized without significant adjunctive fixation (stems, screws, etc.). 7. An implant should never be reused. While it may appear undamaged, imperfection may exist which would reduce the service life of the implant. 8. Use the Genesis Torque Wrench to secure the distal femoral wedges and the conversion modules to the Genesis femoral component with femoral lugs. Use the Genesis II Torque Wrench to secure the distal femoral wedges and the conversion modules to the Genesis II femoral component with femoral lugs. The femoral lugs should be torqued to 70 in-lbs. Use the Mobile Bearing Rotation Peg Torque Wrench to secure the rotation peg to the Mobile Bearing Baseplate. The rotation peg should be torqued to 75 in-lbs. 9. Distal fixation lugs should be used with porous cruciate-retaining femoral components when implanted without cement. These lugs provide medial/lateral stability of the prosthesis. 10. For computer assisted surgery systems, it is extremely important to correctly select input parameters (e.g. bony landmarks). Operators of this equipment should be familiar with the anatomy relevant to the procedure. Failure to provide proper input could cause problems such as a violation of critical anatomical structures and malpositioned implants. Postoperative 1. Postoperative patient care and directions and warnings to patients by physicians are extremely important. Protected weight bearing with external support is recommended for a period of time to allow healing. 2. Use extreme care in patient handling. 3. Postoperative therapy should be structured to prevent excessive loading of the operative knee and to encourage bone healing. 4. Periodic, long-term follow-up is recommended to monitor the position and state of the prosthetic components, as well as the condition of the adjoining bone. Packaging and Labeling Knee implants are sterilized products and should only be accepted if received by the hospital or surgeon with the factory packaging and labeling intact. If the sterile barrier has been broken, refer to the Sterilization/Resterilization section below. STERILIZATION/RESTERILIZATION Most implants are supplied sterile and have been packaged in protective packaging. The method of sterilization is noted on the package label. All radiation sterilized components have been exposed to a minimum of 25 kilograys of gamma radiation. If not specifically labeled sterile, the implants and instruments are supplied nonsterile and must be sterilized prior to use. Inspect packages for punctures or other damage prior to surgery. Metal Components Nonporous or non-ha coated metal components may be resterilized, if necessary, by steam autoclaving in appropriate protective wrapping, after removal of all original packaging and labeling. Protect the devices, particularly mating surfaces, from contact with metal or other hard objects which could damage the product. The following process parameters are recommended for these devices: _ Prevacuum Cycle: 4 pulses (Maximum = 26.0 psig (2.8 bars) & Minimum = 10.0 inhg (339 millibars)) with a minimum dwell time of 4 minutes at 270 F to 275 F (132 C to 135 C), followed by a 1 minute purge and at least 15 minutes of vacuum drying at 10 inhg (339 millibars) minimum. _ For the United Kingdom, sterilization should be carried out in accordance with HTM The recommended prevacuum sterilization cycle is: Evacuation to 100mBar for 2-3 minutes, Negative Pressure pulsing (5): 800mBar-100mBar, Positive Pressure pulsing (5): 2.2Bar 1.1 Bar, Sterilization exposure: 3 minutes at C, Drying vacuum 40mBar for 5-10 minutes. Note: mbar absolute. _ Gravity Cycle: 270 F to 275 F (132 C to 135 C) with a minimum dwell time at temperature of 10 minutes, followed by a 1 minute purge and at least 15 minutes of vacuum drying at 10 inhg (339 millibars) minimum. Smith & Nephew does not recommend the use of low temperature gravity cycles or flash sterilization on implants. If porous coated or HA coated implants are inadvertently contaminated, return the unsoiled prosthesis to Smith & Nephew for resterilization. DO NOT RESTERILIZE porous coated or HA coated implants. The coating requires special cleaning procedures. Plastic Components Plastic components may be resterilized by ethylene oxide gas. The following parameters are recommended as starting points for cycle validation by the health care facility: Sterilant Temp. Humidity Maximum Concentration Exposure Pressure Time 100% EtO 131 F 40-80% 10 PSIA 725 mg/l (55 C) (70% Target) (689 millibars) minutes Suggested initial starting point for aeration validation is 12 hours at 120 F (49 C) with power aeration. Consult aerator manufacturer for more specific instructions. INFORMATION For further information, please contact Customer Service at (800) for all calls within the continental USA and (901) for all international calls. Manufacturing facilities and EC Representative: Smith & Nephew Inc., Orthopaedic Division 1450 Brooks Road Memphis, TN U.S.A Tel.: Smith & Nephew Orthopaedics GmbH Alemannenstrasse Tuttlingen, Germany Tel.: 07462/208-0 Fax: 07462/ Caution: Federal Law (USA) restricts this device to sale by or on the order of a physician. Trademark of Smith & Nephew, Reg. U.S. Pat. & Tm. Off Rev. 0 5/04 17

20 Orthopaedics Smith & Nephew, Inc Brooks Road Memphis, TN USA Telephone: Information: Orders/Inquiries: PROFIX patent numbers: , , , , , , and Additional patents pending. Trademark of Smith & Nephew. Reg. U.S. Pat. & TM Office. This system is intended for cemented use only /04