Effective preoperative planning allows the surgeon to predict the impact of different interventions in order to perform the joint restoration in the most accurate and safe manner. Optimal femoral stem fit, the level of the femoral neck cut, the prosthetic neck length, and the femoral component offset can be evaluated through preoperative radiographic analysis. Preoperative planning also allows the surgeon to have the appropriate implants available at surgery.

The important parameters of preoperative planning include:

• Determination of leg length
• Establishment of appropriate abductor muscle tension and femoral offset
• Determination of the anticipated component size

The overall objective of preoperative planning is to enable the surgeon to gather anatomic parameters which will allow accurate intraoperative placement of the femoral implant.

Determining the preoperative leg length is essential for restoration of the appropriate leg length during surgery. If there are concerns regarding lower extremity or lumbar abnormalities, such as equinus of the foot, flexion or varus/valgus deformities of the knee, or scoliosis, perform further radiographic evaluation to aid in the determination of preoperative leg length status.

An anterior/posterior (A/P) pelvic radiograph often gives enough documentation of leg length inequality to proceed with surgery. If more information is needed, a scanogram or CT evaluation of leg length may be helpful. From the clinical and radiographic information on leg lengths, determine the appropriate correction, if any, to be achieved during surgery.

If the limb is to be significantly shortened, osteotomy and advancement of the greater trochanter or a subtrochanteric shortening osteotomy may be necessary. If the limb is shortened without osteotomy and advancement of the greater trochanter, the abductors will be lax postoperatively, and the risk of dislocation will be high. Also, gait will be compromised by the laxity of the abductors. If leg length is to be maintained or increased, it is usually possible to perform the operation successfully without osteotomy of the greater trochanter. However, if there is some major anatomic abnormality, osteotomy of the greater trochanter may be helpful.

Once the requirements for establishing the desired postoperative leg length have been decided, the next step is to consider the requirement for abductor muscle tension. When templating, center the femoral component in the canal. Choose the offset (i.e., Standard, Lateral or Reduced Lateral) that most closely approximates that of the patient when the new center of rotation is determined (after acetabular component templating). For patients with a very large distance between the center of rotation of the femoral head and the line that is centered in the medullary canal, insertion of a femoral component with a lesser offset will medialize the femoral shaft. To the extent that this occurs, laxity in the abductors will result with a heightened dislocation risk.

Although rare, it may not be possible to restore offset in patients with an unusually large preoperative offset or with a severe varus deformity. In such cases, tension in the abductors can be increased by lengthening the limb, a method that is especially useful when the involved hip is short. If this option is not advisable and if the disparity is great between the preoperative offset and the offset achieved at surgery by using the longest head/neck piece possible, some surgeons may choose to osteotomize and advance the greater trochanter to eliminate the slack in the abductor muscles. Technical variations in the placement of the acetabular components can also reduce the differences in offset.

Preoperative planning for insertion of a cementless femoral component requires at least two radiographic views of the involved femur: an A/P view of the pelvis centered at the pubic symphysis, and a frog leg lateral view on an 11×17-inch cassette. Both views should show at least 8 inches of the proximal femur. In addition, it may be helpful to obtain an A/P view of the involved side with the femur internally rotated. This compensates for naturally occurring femoral anteversion and provides a more accurate representation of the true medial-to- lateral dimension of the metaphysis. When templating, magnification of the femur will vary depending on the distance from the x-ray source to the film, and the distance from the patient to the film. Magnification markers can be used to identify the actual magnification of the radiograph. Knowing this will help to more accurately predict the component size when templating.

The objectives in templating the stem include determining the anticipated size of the implant to be inserted and the location of the femoral neck osteotomy.

To estimate the femoral implant size, assess the body size on the A/P radiograph. Superimpose the template on the metaphysis and estimate the appropriate size of the stem. The body of the stem should fit, or nearly fit, the medial-lateral dimensions of the medullary canal on the A/P x-ray film, and should not be superimposed onto cortical bone.

After establishing the proper size of the stem, determine the height of its position in the proximal femur and the amount of offset needed to provide adequate abductor muscle tension. Generally, if the leg length and offset are to remain unchanged, the center of the head of the prosthesis should be at the same level as the center of the femoral head of the patient’s hip. This should also correspond to the center of rotation of the templated acetabulum. To lengthen the limb, raise the template proximally. To shorten the limb, shift the template distally. The lateral offset option offers lateral translation of 6mm. This allows for an offset increase of 6mm without changing the vertical height or leg length. The femoral head neck length will also affect leg length and offset.

Once the height has been determined, note the distance in millimeters from the underside of the osteotomy line to the top of the lesser trochanter by using the millimeter scale on the template. For example, one might decide from the templating that a 52mm O.D. cup, with a size 15 femoral stem and a 28mm femoral head, placed 15mm above the lesser trochanter, are the appropriate choices. Proximal/distal adjustments in prosthesis position reduce the need for a femoral head with a skirt.

It is crucial to adequately visualize the proximal femur so the correct insertion site for the femoral instruments can be located. Refer to the preoperative planning at this point.

The level of neck resection is determined during preoperative templating. Although specific to each patient, the neck cut often will be approximately 1cm above the lesser trochanter. Perform the neck osteotomy, taking care to maintain the desired angle.

Identify the mid-femoral shaft extension intraoperatively as viewed on the A/P and lateral radiographs. This is usually in the area of the piriformis tendon insertion in the junction between the medial trochanter and lateral femoral neck. Use the One-Piece Box Osteotome to remove this medial portion of the greater trochanter and lateral femoral neck.

The opening must be large enough for the passage of each sequential rasp to help ensure neutral rasp/implant alignment. An insufficient opening may result in varus stem positioning. Use the Rat-Tailed Rasp to remove additional bone from the base of the greater trochanter and to help avoid varus stem positioning.

After removing the cortical bone, use the smallest Femoral Stem Rasp to open the medullary canal. This will provide a reference for the direction of the subsequent femoral rasping.

If planning to use the Calcar Planer, start rasping with the size 8 Rasp. (NOTE: The Calcar Planer can only be used with the size 8 Rasp). If the Calcar Planer will not be used, begin the rasping sequence with a GT Femoral Stem Rasp that is at least two sizes smaller than the estimated implant size. Advance in 1 or 2 size increments until the desired fit and stability is achieved. When inserting the rasp, be sure that it advances with each strike of the mallet. If the rasp can be seated at least 5mm below the osteotomy, progress to the next rasp size and repeat until the predicted final rasp size has been seated.

NOTE: Before using the next size rasp, be sure that the opening is large enough. If it is not, use the one-piece box osteotome or previous rasp again. The opening should not be significantly larger than the rasp or implant

If the predicted final rasp size can be countersunk more than 5mm and adequate cancellous bone is available in the metaphysis region (including the medial calcar), progress to the next larger rasp size after ensuring that there is sufficient room in the distal medullary canal.

The rasps and corresponding implants are sized such that a press-fit is created proximally. The plasma sprayed surface of the implant is slightly proud as compared to the surface. Thus, the implant is more than 1mm larger than the rasp in both the A/P and M/L dimensions. This relationship can be seen on the templates.

NOTE: The metaphyseal press-fit engagement provides the implant with greater rotational stability than the rasp.

Verify the etched size on the rasp and trials before performing a trial reduction. GT Modular Neck Trials and Femoral Head Trials are available to assess proper component position, joint stability, range of motion, and leg length.

NOTE: For Standard offset, utilize the SILVER-colored Modular Neck Trials that are marked “STD”. For Lateral offset, utilize the BLACK-colored Modular Neck Trials that are marked “LAT”. For Reduced Lateral, utilize the GOLD-colored Modular Neck Trials that are marked “RED”.

Once the acetabular cup implant and Acetabular Trial Insert are also in place, you can perform a trial reduction of the construct.

Check the leg length and offset of the femur by referencing the lengths measured prior to dislocation of the hip. It is important at this stage to reposition the leg exactly where it was during the first measurement. Adjust the neck length by changing the Femoral Head Trial to achieve the desired result.

NOTE: When changing the head trials from the neck trial, apply a twisting motion to the head trial, while pulling axially.

Remove all of the trial components when trial reduction is complete.

Insert the femoral stem implant into the canal until it will no longer advance with hand pressure, which is approximately 1mm to 2mm above the final seated position. The Threaded Femoral Stem Inserter is threaded to allow the surgeon to control the femoral stem implant during insertion. A GT Femoral Stem Inserter is also available to allow some rotational freedom during insertion. The threaded insertion hole on the implant will accept either Femoral Stem Inserter.

NOTE: To reduce the potential for fracture, allow the femoral stem implant to follow the prepared envelope.

Apply the selected Femoral Stem Inserter to the femoral stem implant and begin to tap the handle with a mallet until the implant will no longer advance.

NOTE: Do not continue to try to advance the prosthesis once it has made contact with the cortical bone in the medial calcar.

The prosthesis should be seated when the most proximal part of the plasma sprayed surface is level with the osteotomy line. If the implant does not advance with each strike of the mallet, stop insertion. If the stem is too proud, consider removing the component. Rasp additional bone from the areas that are preventing the insertion and insert the femoral stem implant again.

Following the implantation of the femoral stem, as well as the acetabular cup and poly liner, it is necessary to impact the head onto the stem taper.

Irrigate, clean, and dry the femoral stem to ensure the taper is free of debris. Before reducing the hip, place the appropriate femoral head onto the taper and tap using the Universal Femoral Head Impactor.

Once the entire construct is implanted, perform a final reduction to assess and confirm range of motion, hip stability, and limb length.

The ICONACY i-Hip™ RS acetabular cup System consists of a hemispherical titanium alloy acetabular cup (i.e., shell) mated with a highly cross-linked ultra- high molecular weight polyethylene (i.e., poly) liner that is locked into the cup with a ring. The i-Hip™ RS acetabular cup System articulates with the femoral stem device assembly in the ICONACY™ i-Hip™ Femoral Stem System.

The i-Hip™ RS cup implant (i.e., cup) is machined from forged Ti-6Al-4V ELI alloy. The cup is provided in sizes 46mm to 64mm, in 2mm increments. The cup has a threaded, central polar hole to mate with a threaded insertion tool. The cup is available with two, peripheral screw holes to permit the use of bone screws for adjunct fixation. The finned cup does not have peripheral screw holes.

The outer hemispherical surface of the cup has a porous coated, titanium plasma spray for cementless, press-fit fixation. The inner surface of the cup has a very smooth surface (0.8μm Max Ra) to minimize the possibility of wear between the inner surface of the cup and the hXl UHMWPE poly liner.

A titanium alloy cup locking ring is fixed in a locking groove at the inner surface of the shell, near the periphery or mouth of the shell. The cup locking ring will engage the groove in the hXL UHMWPE poly liner to lock it into the cup.

The poly liner has a smoothly finished outer surface to seat with the smooth inner surface of the cup for the associated, compatible sizes. The articulating surface of the poly liner is smoothly finished (0.4μm Max Ra) to minimize wear when coupled with the polished femoral heads. The poly liners have a series of lugs that mate with similar recesses at the mouth of the cup so that the poly liner can resist rotational forces that may be applied to the acetabular device assembly.

Complete exposure of the acetabulum is essential to accurately prepare the bone and position of the implant.

Progressively ream the acetabulum, in 1mm to 2mm increments, with the acetabular Reamers until healthy, bleeding, cancellous bone is reached and a hemispherical dome is achieved.

NOTE: each surgeon’s approach may vary. The selected surgical approach must provide adequate exposure to visualize the entire acetabular rim. This will reduce the likelihood of soft tissue entrapment, which may prevent the cup from fully seating.

NOTE: In order to achieve a press-fit, surgical judgement and adequate bone stock are required to assess appropriate reaming. Press-fit is achieved by careful bone preparation and accurate implant placement.

NOTE: The true external diameter of the cup, including the porous coating, corresponds directly to the labeled size. A cup sized 2mm over the reamed preparation (size of last reamer used) will provide 2mm press-fit at the rim. A 1mm press-fit may be desired with hard bone.

Once the appropriate dome size has been achieved, assemble the proper size cup to the Acetabular Cup impactor handle. With the acetabular cup impactor handle tip placed, rotate the thumbwheel clockwise to thread and secure the implant to the assembly. the labeled outside diameter (O.D.) of the cup represents the true hemispherical diameter of the implant.

To assist with ensuring optimal cup positioning in abduction and anteversion intraoperatively, utilize the Acetabular Cup positioning guide by attaching it to the acetabular cup impactor handle. Range of motion and stability are optimized when the cup is placed in approximately 35 to 45 degrees of abduction. achieving an abduction angle to a maximum of 45 degrees, and 10 degrees to a maximum of 20 degrees of anteversion angle, is appropriate in most cases. Variation in placement of the cup will depend on the patient’s anatomy and intraoperative surgical judgement.

With the acetabular cup implant in the appropriate position and alignment, use a mallet to impact the acetabular cup impactor handle. When the cup implant is fully seated, remove the acetabular cup impactor handle. To assist with releasing the handle from the cup, utilizing the apex hole at the dome can assist in confirming that the cup is fully seated in the bone cavity.

NOTE: Uneven intraoperative tamping or impacting (i.e., adjustment) of the periphery of the cup is not recommended. If adjustment is necessary or unavoidable, please ensure the associate acetabular insert trial is inserted into the cup to protect cup locking ring.

Prior to poly liner implantation, it is important to assess proper component position, joint stability, range of motion, and leg length utilizing the Acetabular Insert trials.

Insert the appropriately sized Acetabular Insert Trial into the implanted acetabular cup by hand.

Once the final size Femoral Rasp, as well as the associated Modular Neck Trial and Femoral Head Trial are in place, perform a joint trial reduction.

Remove the Acetabular Insert Trial once the size has been selected and confirmed. If removal by hand is difficult, utilize the Liner Impactor Handle for extraction by threading it onto the acetabular insert trials, in situ.

Remove all of the trial components when trial reduction is complete.

If bone screw placement is desired, drill a pilot hole through the selected peripheral hole using the 3.2mm diameter Drill Bit on the Angled Drill Driver. The apex hole at the dome of the cup cannot be used for bone screw fixation.

Position the Drill Bit assembly through the Drill Guide and into the selected peripheral screw hole. Drill a screw hole and use the Depth Gauge to measure its depth.

Select the appropriate length 6.5mm diameter i-Hip™ Bone Screw. Use the Universal Joint Screw Driver to insert and seat the bone screw into the drilled hole.

After seating the bone screw, check to ensure that the head is below the inner diameter of the cup. place an additional bone screw if desired and permissible.

To remove a bone screw, engage the screw with the Universal Joint Screw Driver and turn counterclockwise.

Prior to inserting the selected poly liner, ensure that the cup interior is clean and dry. place the poly liner into the implanted cup by hand and rotate the poly liner until the lugs are aligned for final engagement.

Select the proper sized Liner Impactor Head and attach it to the liner impactor handle. place the liner impactor on the poly liner and strike the liner until it is fully seated in the cup.

NOTE: For visual confirmation of poly liner locking, ensure that the locking ring eyelets have centered within the locking ring window. The locking ring eyelets should have zero to minimal gap relative to the center post. Neither locking ring eyelet should have any excessive gap relative to the center post.

Once the entire construct (i.e., i-Hip™ acetabular cup and Femoral Stem Systems) is implanted, perform a final reduction to assess and confirm range of motion, hip stability, and limb length.

If a poly liner requires removal intraoperatively, inspect the cup locking mechanism for damage. if necessary, the cup locking ring can be replaced independent of the entire cup implant.

In order to remove and extract the poly liner, move one eyelet clockwise, to release the pressure, then use the open chamfers to pry out the liner.

The stability of a new poly liner should be assessed through trial reduction.

If the RS cup locking ring is damaged, remove and replace it with the appropriate size and type (i.e., RS locking ring. Replacement RS cup locking rings are provided separately.

Verify the etched size on the rasp and trials before performing a trial reduction. GT Modular Neck Trials and Femoral Head Trials (Fig. 8) are available to assess proper component position, joint stability, range of motion, and leg length.

NOTE: For Standard offset, utilize the SILVER-colored Modular Neck Trials that are marked “STD”. For Lateral offset, utilize the BLACK-colored Modular Neck Trials that are marked “LAT”. For Reduced Lateral, utilize the GOLD-colored Modular Neck Trials that are marked “RED”.

Once the acetabular cup implant and Acetabular Trial Insert are also in place, you can perform a trial reduction of the construct.

Check the leg length and offset of the femur by referencing the lengths measured prior to dislocation of the hip. It is important at this stage to reposition the leg exactly where it was during the first measurement. Adjust the neck length by changing the Femoral Head Trial to achieve the desired result.

NOTE: When changing the head trials from the neck trial, apply a twisting motion to the head trial, while pulling axially.

Remove all of the trial components when trial reduction is complete.

Insert the femoral stem implant into the canal until it will no longer advance with hand pressure, which is approximately 1mm to 2mm above the final seated position (Fig. 9). The Threaded Femoral Stem Inserter is threaded to allow the surgeon to control the femoral stem implant during insertion. A GT Femoral Stem Inserter is also available to allow some rotational freedom during insertion. The threaded insertion hole on the implant will accept either Femoral Stem Inserter.

NOTE: To reduce the potential for fracture, allow the femoral stem implant to follow the prepared envelope.

Apply the selected Femoral Stem Inserter to the femoral stem implant and begin to tap the handle with a mallet until the implant will no longer advance (Fig. 10).

NOTE: Do not continue to try to advance the prosthesis once it has made contact with the cortical bone in the medial calcar.

The prosthesis should be seated when the most proximal part of the plasma sprayed surface is level with the osteotomy line. If the implant does not advance with each strike of the mallet, stop insertion. If the stem is too proud, consider removing the component. Rasp additional bone from the areas that are preventing the insertion and insert the femoral stem implant again.

Following the implantation of the femoral stem, as well as the acetabular cup and poly liner, it is necessary to impact onto the taper of the stem

Irrigate, clean, and dry the femoral stem to ensure the taper is free of debris. Before reducing the hip, place the appropriate femoral head onto the taper and tap using the Universal Femoral Head Impactor (Fig. 11).

Once the entire construct is implanted, perform a final reduction to assess and confirm range of motion, hip stability, and limb length.