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Reliance CM Femoral Component
Using the Command
Instrument System
Surgical Technique
The Partnership™ System, which includes the Re1ianceCM Femoral Component and the CommandInstruments, is a collaboration between Howmedica and a group of orthopaedic surgeons and biomedical design engineers. This team has developed an integrated series of implants and instruments designed to address the needs of patients, surgeons, and O.R. staff in today's changing healthcare environment. The design group includes:

Lester S. Borden, MD
Head of Adult Reconstructive Surgery
Cleveland Clinic Foundation, Cleveland, OH

Fdward T. Habermann, MD
Professor and Chairman
Department of Orthopaedic Surgery
Albert Einstein College of Medicine
Orthopaedic Surgeon-in-Chief
Montefiore Medical Center
Albert Einstein College of Medicine, Bronx, NY

Anthony K. Hedley, MD, FRCS
Chairman, Department of Orthopaedic Surgery
St. Luke's Medical Center, Phoenix, AZ

David S. Hungerford, MD
Chief, Division of Arthritis Surgery
Professor of Orthopaedic Surgery
Johns Hopkins University, Baltimore, MD
Chief of Orthopaedic Surgery
Good Samaritan Hospital, Baltimore, MD

Kenneth A. Krackow, MD
Professor of Orthopaedic Surgery
State University of New York at Buffalo
Department Head
Department of Orthopaedic Surgery
Buffalo General Hospital, Buffalo, NY

Roger N. Levy, MD

Chief of Arthritis Surgery
Mt. Sinai Medical Center, New York City, NY

Joseph C. McCarthy, MD
The Department of Orthopaedic Surgery
New Fngland Baptist Hospital, Boston, MA
Associate Clinical Professor
Tufts University School of Medicine, Boston, MA

Philip C. Noble, PhD
Dunn Professor of Orthopedic Research
The Methodist Hospital, Houston, TX

Hugh S. Tullos, MD
Wilhelmina Barnhart Chairman
Department of Orthopedic Surgery
Baylor College of Medicine, Houston, TX

Roderick H. Turner, MD
The Department of Orthopaedic Surgery
New England Baptist Hospital, Boston, MA
Tufts University, Boston, MA


Technique Options

The Command™ Instrument System is extremely versatile, offering surgeons great flexibility in approaching the implantation of the Reliance™ CM Femoral Component. This publication presents a basic technique, followed by three appendices. Appendix I presents options for Starting; Appendix II presents options for Reaming; and Appendix III presents Technique Options at-a-Glance, an over view of the system. These options allow surgeons to customize the Command™ Instrument System to an approach that suits individual preferences and circumstances.

Preoperative Templating

The Re1iance™ CM Hip System offers a complete set of femoral templates. All templates are at 120% magnification.

Acetabular Options

Howmedica offers a wide variety of acetabular components that are compatible with the Re1iance™ CM Femoral Component. The surgeon should refer to a specific acetabular component's surgical technique for a discussion of acetabular surgical procedures.

Surgical Approach

Each surgeon should use the surgical approach for total hip arthroplasty with which he is most familiar. Patient positioning, prepping and draping, the skin incision, soft tissue dissection, and hip dislocation are performed according to the surgeon's preferred technique, making certain to adequately expose the acetabulum and the proximal femur.

This publication sets forth recommended procedures for using Howmedica devices and instruments. It offers guidance that you should heed, but, as with any such technical guide, each surgeon must consider the particular needs of each patient and make appropriate adjustments when and as required.

*Command: Patents Pending.


STARTING*

Determine and Mark the Osteotomy Level

By using anatomic landmarks identified during templating, the osteotomy guide identifies the location of the osteotomy cut. The osteotomy guide has several features to assist the surgeon:

  • [A]Long tail of the osteotomy guide for alignment with the femoral shaft axis.

  • [B]Notch in the proximal portion of the guide references the proximal tip of the greater trochanter.

  • [C]Location holes determine the center of rotation for the head position options available for stem size.

Care must be taken to restore proper leg length by referencing the osteotomy level back to the center of rotation of the implanted acetabular component. The resection level, relative to the lesser trochanter, should be about a fingerbreadth above. Angled surface provides a plane for marking the level of the cut, or can be used as a cutting surface for the sawblade.

Perform Osteotomy

40° osteotomy angle allows single cut across the neck, and generally eliminates the need for a second cut to complete the resection.

*Additional options availble; see Appendix 1.

Open and Size the Canal with Starter Awl

The tapered starter awl is a hand-operated instrument designed to open the femoral canal and indicate distal diameter size. Assemble small hex T-handle onto starter/sizer awl, and target piriformis fossa to open canal. Progress the awl distally until some cortical resistance is achieved. Use aggressive cutting teeth of starter awl to achieve lateralization.

Depth of Starter Awl

Make note of millimeter diameter marking that appears at the medial osteotomy level. These markng grooves on shaft identify distal diameter sizing of femoral canal.


REAMING*

Assemble and Introduce Straight Reamer

Assemble a power adaptor or large hex T-handle, if preferred, to the straight, cylindrical reamer. Select diameter of reamer based on starter awl diameter reading, starting with a size one or two millimeters smaller.

Use of the Straight Reamer and Depth Markings

Ensure the reamer is directed laterally and into a neutral position. Insert reamer until the most proximal depth marking groove is aligned with the medial edge of the osteotomy.

NOTE: When lateralizing rigid reamers, take care to properly retract/protect the abductor muscle fibers of the gluteus minimus/medius at the superior tip of the greater trochanter.

*Additional options available; see Appendix II.


BROACHING

Select Fully Toothed Broach

There are two styles of broaches available: Fully Toothed (cemented) and Universal. The Fully Toothed broach is featured here. Select a broach one size smaller than the anticipated implant size, based on preoperative templating. Attach handle to broach by inserting trunnion of the broach into broach handle and turning the locking knob in the direction indicated.

Introduce Broach

Introduce broach into proximal femur. Drive the broach down the canal with a mallet, keeping it aligned with the neutral femoral axis. Assess fit and resistance to movement. If a larger size is needed, remove the broach and replace it with the next size. To facilitate final seating of the broach, partially withdraw the broach to clear cutting teeth of bone; then re-introduce the instrument into the canal.

Calcar Planer

Leave the final broach seated in the canal. Remove the broach handle. The broach trunnion may be used as a guide for the calcar planer. The calcar planers come in two sizes: standard and large. Select the proper size planer and assemble to power adaptor. The female bushing on the planer is guided over the broach trunnion. The medial calcar should be leveled to aid the collar calcar contact.

Fit Neck Trial to Trunnion

Disassemble the broach handle, and select appropriate size neck trial corresponding to broach/implant size, and push the trunnion securely onto the broach.


COMPLETION

Attach Head Trial

Select the head diameter [26mm, 28mm, or 32mm] according to surgeon preference. The head trials have a circumferential groove which identifies the level of the center of rotation. Select neck length: -4mm, *Std., +4mm, +8mm, +12mm, +l6mm** based on preoperative templating. Attach the head trial to the neck trial and perform a trial reduction, assessing the hip for stability, leg length, and over all range of motion. Remove the broach and all trials.

*NOTE: +16mm is only suitable for stem sizes #4 and above; -4mm is not available in 26mm head sizes. Refer to sizing chart on page 19.

Insert Cement

Thoroughly clean and dry the canal. Insert a bone plug to a level 20mm distal to end of stem. Prepare the bone cement. Pump cement into the canal in retrograde fashion, retracting the nozzle as back pressure is felt. When the canal is filled with cement, place the appropriate pressurizing seal in the mouth of femur. Slide the cement nozzle through the seal and introduce remaining cement under pressure. Retain a small bolus of bone cement to serve as guide when the cement in the canal has cured.

Assemble Introducer to Implant

Assemble the insertion tool to the implant. Make sure that the distal tip of the instrument is correctly mated to the orientation keyway of the insertion feature of the implant. For ease of assembly, hold the hands as illustrated in the photograph at right, using the thumb to turn the locking knob. Fully and securely attach the instrument to the stem.

Select and Attach Distal Spacer

The correct size of the distal centralizer is deterined by the diameter of the distal canal. Each centralizer will fit into the distal hole of any stem size and is held in place via taper lock. The distal centralizer will guide the Reliance into neutral alignment during insertion.

Insert the Implant

Insert the implant. The handle can be used to control anteversion as you implant the prosthesis. Remove the inserter by turning the locking knob on the top of the stem inserter.

Final Trial Reduction

A head trial can be placed onto the implant and a final trial reduction performed.

Impact Head onto Stem

Select appropriate size Howmedica V40™ femoral head, wipe trunnion clean, and impact head on trunnion with femoral head impactor.

NOTE: Only Howmedica V40™ femoral heads labeled as 40' taper may be used with the stems in this system.

Reduce Joint and Close

Relocate the femoral head into the acetabular cup and check the laxity and range of motion. The surgical site is then closed according to the surgeon's standard procedure for the surgical approach chosen.


APPENDIX I
STARTING OPTIONS

The Starter Kit has three technique options to open and size the femoral canal. The options contain both standard and new methods to gain access to the femoral canal and to ensure a neutral/lateral start for each subsequent instrument.

Starting Option 1: Starter Awl (Presented in Basic Technique)

Open and Size the Canal with Starter Awl

The tapered starter awl is a hand-operated instrument designed to open the femoral canal and indicate distal diameter size. Assemble small hex T-handle onto starter/sizer awl, and target pin formis fossa to open canal. Progress the awl distally until some cortical resistance is achieved. Use aggressive cutting teeth of starter awl to achieve lateralization.

Depth of Starter Awl

Make note of millimeter diameter marking that appears at the medial osteotomy level. These marking grooves on shaft identify distal diameter sizing of femoral canal.

Starting Option 2: Box Chisel

There are three sizes of the box chisels: the small size corresponds to the Reliance™ CM femoral implant size #1; the medium to sizes #2 to #5.

Box Chisel Technique Variation A

The box chisel may be used to open the proximal femur prior to use of the tapered starter/sizer awl. After the osteotomy has been performed, the appropriate size box chisel is selected and introduced into the axis of the femoral shaft, starting lateral to the cortex of the neck. This will remove a wedge of bone at the medial base of the greater trochanter, helping to achieve neutral/lateral alignment of the tapered starter/sizer awl.

Box Chisel Technique with Box Chisel Guide Variation B

The box chisel may also be used with the sharp trochar point box chisel guide. Assemble the box chisel guide to the box chisel by threaded engagement. The box chisel guide is inserted into the long axis of the femur, targeting the piriformis fossa; the guide will serve to direct/align the box chisel cutting head.

Box Chisel Technique with the Starter Awl Variation C

The box chisel may also be used with the tapered starter/sizer awl. After the awl has been used to open and size the femoral canal, the small hex T-handle may be removed with the awl engaged in the isthmus of the femoral canal. The shaft of the awl may now be used as an axial guide coinciding with the long axis of the femur. The box chisel is cannulated so that it slides over the shaft of the awl, removing a wedge of bone at the medial base of the greater trochanter.

Starting Option 3: Proximal Reamer Sleeves with the Starter Awl

The System's proximal reamer sleeves come in three sizes. Those applicable to the Reliance™ CM femoral components are: small (#1) and medium (#2-#5). After the tapered starter awl has been used to open and size the distal femoral canal, remove it from the femur and assemble the appropriate size proximal reamer sleeve. Re-introduce the assembly of the proximal reamer sleeve and awl distally into the femoral canal. Lateralize the proximal reamer sleeve to manually groove out the medial aspect of the greater trochanter. The depth of insertion has been established in the previous step. The intent of the proximal reamer sleeve is to attain neutral alignment by lateralizing into the greater trochanter.

NOTE: When lateralizing rigid reamers, take care to properly retract/protect the abductor muscle fibers of the gluteus mininus/medius at the superior tip of the greater trochanter.


APPENDIX II
Reaming Options

Presented here are five technique options for Reaming the femoral canal, using the Command™ Instrument System:

Option 1: Straight Reamer
Option 2:
Gray
Fixed Head IM Flexible Reamer
Option 3: Gray
Fixed Head IM Flexible Reamer and Proximal-Conical/Distal-Bullet Reamer
Option 4: Straight Reamer and Proximal-Conical/Distal-Bullet Reamer
Option 5:
Proximal-Distal Baton Reamer

An alternative approach is to omit the medullary reaming stage altogether. The femoral canal may be prepared by simply using the starter options and fully toothed broaches.


Reaming Option 1: Straight Reamer

Assemble and Introduce Straight Reamer

Assemble a power adaptor or large hex T-handle, if preferred, to the straight, cylindrical reamer. Select diameter of reamer based on starter awl diameter reading, starting with a size one or two millimeters smaller.

Use of the Straight Reamer and Depth Markings

Ensure the reamer is directed laterally and into a neutral position. Insert reamer until the most proximal depth marking groove is aligned with the medial edge of the osteotomy.

NOTE: When lateralizing rigid reamers, take care to properly retract/protect the abductor muscle fibers of the gluteus minimus/medius at the superior tip of the greater trochanter.

Reaming Option 2: Gray™ Fixed Head IM
Flexible Reamer

Gray™ Fixed Head IM Flexible Reamer

To prepare the cylindrical, distal diameter using flexible reamers rather than straight cylindrical reamers, select diameter of reamer based on starter awl diameter reading. Start with a size one or two millimeters smaller.

Reaming Option 3: Gray™ Fixed Head IM Flexible Reamer and Proximal-Conical/ Distal-Bullet Reamer

Gray™ Fixed Head IM Flexible Reamer

To prepare the cylindrical, distal diameter using flexible reamers rather than straight cylindrical reamers, select diameter of reamer based on starter awl diameter reading. Start with a size one or two millimeters smaller.

Select Proxima1-Conical/Distal-Bullet Reamer

Select proximal-conical/distal-bullet reamer corresponding to the size of the implant determined by preoperative templating and the preceding cylindrical reaming. Each size implant has a correponding proximal-conical/ distal-bullet reamer. These reamers have the large hex drive fitting, which can be attached to the power adaptor or used with the large manual T-handle.

Position Distal-Bullet Reamer and Gauge Depth

Insert proximal-conical/distal-bullet reamer into the canal, maintaining neutral/lateral alignment and achieving lateralization. Insert reamer until the most proximal depth marking groove is aligned with the medial edge of the osteotomy.

Reaming Option 4: Straight Reamer and Proximal-Conical/Distal-Bullet Reamer

Assemble and Introduce Straight Reamer

Assemble a power adaptor or large hex T-handle, if preferred, to the straight, cylindrical reamer. Select diameter of reamer based on starter awl diameter reading, starting with a size one or two millimeters smaller.


Use of the Straight Reamer and Depth Markings

Ensure the reamer is directed laterally and into a neutral position. Insert reamer until the most proximal depth marking groove is aligned with the medial edge of the osteotomy.

NOTE: When lateralizing rigid reamers, take care to properly retract/protect the abductor muscle fibers of the gluteus minimus/medius at the superior tip of the greater trochanter.

Select Proximal-Conical/Distal-Bullet Reamer

Select proximal-conical/distal-bullet reamer corresponding to the size of the implant determined by preoperative templating and the preceding cylindrical reaming. Each size implant has a corre sponding proximal-conical/distal-bullet reamer. These reamers have the large hex drive fitting, which can be attached to the power adaptor or used with the large manual T-handle.

Position Proximal-Conical/Distal-Bullet Reamer and Gauge Depth

Insert proximal-conical/distal-bullet reamer into the canal, maintaining neutral/lateral alignment and achieving lateralization. Insert reamer until the most proximal depth marking groove is aligned with the medial edge of the osteotomy.

Reaming Option 5: Proximal-Distal Baton Reamer

Proximal-Distal Baton Reamer

The proximal-distal baton reamer is designed to combine the distal cutting of the straight IM reamer and the proximal cutting of the proximal-conical/distal-bullet reamer. [This reamer is also known as the ONE-STEP reamer.]

Introduce Proximal-Distal Baton Reamer

Assemble a power adapter or large hex T-handle, if preferred, to the proximal-distal baton reamer. Select the reamer that corresponds to the implant size as determined by preoperative templating and the distal diameter of the femoral canal as determined by the tapered starter/sizer awl. Each size implant has a corresponding proximal-distal baton reamer that will simultaneously prepare the distal diameter and proximal-conical region of the femoral canal. Insert proximal-distal baton reamer into the canal, maintaining neutral/lateral align ment and achieving lateralization. Advance the reamer distally until the depth marking groove is aligned with the medial edge of the osteotomy.

 

Reliance™ CM Femoral Component
Stem Size
Stem Length
Minimum Distal
Canal Diameter
Required
Neck Angle
#1 100mm 11mm  

132°

#2 115mm l2mm
#3 13mm
#4 125mm 14mm
#5 15mm
Neck Length*
Stem Size Short**
-4m
Standard
0mm
Medium
+4mm
Long
+8mm
X-Long
+12mm
XX-Long
+16mm
#1 27mm 31mm 35mm 39mm 43mm N/A
#2 28mm  32mm  36mm  40mm 44mm N/A
#3 30mm 34mm 38mm 42mm 46mm N/A
#4 31mm 35mm 39mm 43mm 47mm 51mm
#5 33mm 37mm 41mm 45mm  49mm 53mm
Femoral Head Offset*
Stem Size Short**
-4mm
Standard
Omm
Medium
+4mm
Long
+8mm
X-Long
+l2mm
XX-Long +16mm
#1 31mm 34mm 37mm 40mm 43mm N/A
#2 33mm 36mm 39mm 42mm 45mm N/A
#3 37mm 40mm 43mm 46mm 49mm N/A
#4 41mm 44mm 47mm 50mm 53mm 56mm
#5 44mm 47mm 50mm 53mm 56mm 59mm

*Heads avai1ab1e in 26mm, 28mm, and 32mm diameters.
**Not available in 26mm diameter head.


APPENDIX III
Technique Options at-a-Glance

The Command Instrument System offers great flexibility when approaching implantation of the Reliance CM Femoral Component.