WRIGHT Medical

EVOLVE Proline Plus Radial Head and Repair System SURGICAL TECHNIQUE

32 Pages

File Type: PDF

File Size: 2.46 MB

File Name: WRIGHT Medical - 009397B - EVOLVE Proline Plus Radial Head and Repair System SURGICAL TECHNIQUE - 2015-07.pdf

Preview

Page 1

EVOLVE Proline Plus ®

Radial Head and Repair System SURGIC A L T ECHNIQUE

Contents

Chapter 1

Device Description

Chapter 2

Intended Use

Chapter 3

Preoperative Planning

Chapter 4

Surgical Technique

Skin Incision

Direct Lateral Dissection

Resection

Trial Head Selection

Stem Broaching

Neck Planing

Trial Stem Selection

Trial Stem and Head Insertion

Validate Trial Sizing

Trial Head and Stem Removal

Implant Insertion Using Back Table Implant Assembly

Implant Insertion Using In Situ Assembly

Locker Assembly

Closure

Explant Information

Postoperative Management

EVOLVE® Proline Plus Radial Head and Repair System

Screw Preparation

Screw Placement

Postoperative Management

EVOLVE® TRIAD™ 2.5mm Cannulated Bone Scews

EVOLVE® TRIAD™ 2.0mm Bone Scews (Outside Plate)

Appendix

Ordering Information

Wright recognizes that proper surgical procedures and techniques are the responsibility of the medical professional. The following guidelines are furnished for information purposes only. Each surgeon must evaluate the appropriateness of the procedures based on his or her personal medical training, experience, and patient condition. Prior to use of the system, the surgeon should refer to the product Instructions For Use package inserts 146884 and 146886 for additional warnings, precautions, indications, contraindications and adverse effects. Instructions For Use package inserts are also available by contacting the manufacturer. Contact information can be found on the back of this surgical technique. The Instructions For Use package inserts are available on wmt.com under the link for Prescribing Information. Please contact your local Wright representative for product availability.

Presented by Graham King, MD

chapter

Device Description

The EVOLVE® Proline RH System is the culmination of years of laboratory and clinical research as well as over 50,0001 clinical implantations of the EVOLVE® Radial Head prosthesis. It is the state of the art for modular radial head arthroplasty. The smooth stem design continues to be utilized and is now supported by numerous studies2-5 including two long term studies. The Harrington study,4 published in the Journal of Trauma in 2001, included a patient cohort of 20 patients with acute comminuted radial head fractures, with a mean follow-up of 12 years with a range of 6-29 years. This study concluded that a smooth stem radial head “functions well on a long-term basis”. It also concluded that “good to excellent results can be anticipated in approximately 75% of patients and the overall complication rates are acceptable.” The King study,5 presented at the Annual ASSH Meeting in September, 2006, included a consecutive patient cohort of 32 patients who underwent smooth stem radial head arthroplasty for elbow reconstruction with a mean follow-up of 8 years. The King study concluded that “metallic radial head arthroplasty for elbow reconstruction is a safe and durable procedure that provides patients with long term functional range of motion and pain relief.” Conceptually, the annular ligament guides the motion of the EVOLVE® Radial Head prosthesis optimally with the capitellum and the proximal radial ulnar joint rather than relying on the motion patterns of the radial neck. Given that the native radial head is not circular and the articulation with the capitellum is usually offset from that of the radial neck, there is a natural cam effect which occurs during forearm rotation that is difficult for an off-the-shelf axisymmetric implant to replicate. Even eccentrically designed prosthetic implants cannot precisely reproduce the native anatomy and motion patterns due to the highly variable shape of the proximal radius.6 The EVOLVE® Radial Head prosthesis utilizes a spacer concept with a smooth stem. The smooth stem can move slightly in the proximal radius so that the radial head tracks optimally with the articular surfaces, reducing abnormal kinematics and therefore problems with articular wear and pain. While the slight movement of the smooth stem in the radial neck can cause some radiolucency, this is not a source of concern. Our long term experience with this design shows that this radiolucency does not progress beyond 1 year and is not a source of pain.

1. Internal sales data as of February, 2013. 2. Grewal R, MacDermid J, Faber K, Drosdowech D, King, G. Comminuted radial head fractures treated with a modular metallic radial head arthroplasty. Journal of Bone and Joint Surgery. October, 2006. 3. Moro JK, Werier J, MacDermid JC, Patterson SD, King GJ. Arthroplasty with a metal radial head for unreconstructible fractures of the radial head. Journal of Bone and Joint Surgery. August, 2001. 4. Harrington IJ, Sekyi-Out A, Barrington TW, Evans DC, and Tuli V. The functional outcome with metallic radial head implants in the treatment of instable elbow fractures: a long term review. Journal of Trauma. Jan. 2001. 5. Shore B, MacDermid J, Faber K, King G. Outcome of metal radial head arthroplasty in elbow reconstruction. Annual Meeting of ASSH, Sept. 2006. 6. King G, Zarzour Z, Patterson S, Johnson J. An anthropometric study of the radial head. The Journal of Arthroplasty. 16:112-116, 2001.

Chapter 1

Device Description

Design Rationale (cont’d) In contrast, a malarticulating implant with a well-fixed stem causes high contact pressures on the opposing articular cartilage and can lead to early failure. An alternative approach is the use of a bipolar articulation. While this at first seems attractive, the issues of polyethylene wear and particulate debris are a real concern given the relatively young age at which most radial head implants are employed. Furthermore, a bipolar implant is less effective at maintaining elbow and forearm stability due to a tendency of the articulation to angulate under load. The EVOLVE® Proline RH System continues to offer the two part, modular implant design that gives surgeons the ability to appropriately match the patient’s anatomy. The original sizing of the implant system is based on an anthropometric study6 of the proximal radius. This research demonstrated a wide variability in the size and shape of the radial head as well as a poor correlation of the size of the radial head with the dimensions of the medullary canal of the radial neck. Based on this study and extensive clinical experience, the EVOLVE® Proline RH System head sizes now range from 18 to 28mm in diameter and stem sizes now range from 4.5 to 9.5mm diameter. | FIGURE 1 Furthermore, the system now has three head heights and three stem heights that enable precise replication of the native radial head articulation with the proximal radioulnar joint. STANDARD STEM IMPLANTS

STANDARD HEAD SIZES SIZE 18mm

SIZE 20mm

SIZE 26mm

+ 2 HEAD SIZES SIZE 18mm/ +2

SIZE 20mm/ +2

SIZE 22mm/ +2

SIZE 24mm/ +2

SIZE 28mm/ +2

SIZE 26mm/ +2

SIZE 5.5mm

SIZE 4.5mm

SIZE 28mm 10.5

9.5

8.5

SIZE 24mm

SIZE 22mm

Optional

SIZE 6.5mm

5.5

6.5

7.5

8.5

9.5

+ 2 STEM IMPLANTS SIZE 5.5mm/ +2

SIZE 4.5mm/ +2

SIZE 20mm/ +4

SIZE 22mm/ +4

SIZE 24mm/ +4

Optional

+ 4 HEAD SIZES SIZE 18mm/ +4

SIZE 28mm/ +4

SIZE 26mm/ +4

| FIGURE 1

13.5

12.5

Optional

4.5

5.5

6.5

7.5

8.5

9.5

Optional

+ 4 STEM IMPLANTS SIZE 5.5mm/ +4

SIZE 4.5mm/ +4

Optional

SIZE 8.5mm/ +4

SIZE 7.5mm/ +4

SIZE 6.5mm/ +4 4

SIZE 9.5mm/ +4 4

4.5

5.5

6.5

7.5

8.5

9.5

Optional

Every instrument in the EVOLVE® Proline RH System has been updated to give surgeons a simpler and more precise technique. The broaching, trialing and implant assembly instrumentation has been enhanced. The most dramatic change is the new in situ assembly device which allows for easier implant insertion and less surgical trauma to the joint. The in situ Locker provides confident implant assembly, even in small, tight elbows with intact ligaments. The Locker engages the reliable Morse taper connection of the EVOLVE® implant; there are no set screws or polyethylene to wear out or fail over time. Our testing has shown that an implant locked with the new in situ Locker would require 1195N of actual force on average before disassembly could occur.7 7. Internal test data available.

14.5

SIZE 9.5mm/ +2 2

Optional

SIZE 8.5mm/ +2

SIZE 7.5mm/ +2

SIZE 6.5mm/ +2 2

12.5

11.5

10.5

SIZE 9.5mm

4.5

Optional

SIZE 8.5mm

SIZE 7.5mm

Chapter 1

Device Description

Radial head fractures that can be repaired may require the use of plates.1 The EVOLVE® Proline Plus System is designed to address fixation of these fractures.

Radial Head and Neck Plates • Polished Stainless Steel material • Optimized screw trajectories allow for fixation of multiple fragments • ORTHOLOC® Mini Polyaxial Locking design allows for off axis placement of locking screws up to 10 degrees • Round holes compatible with Locking or Non-Locking Screws o 2.0mm ORTHOLOC® Mini Polyaxial Locking Screws o 2.0mm EVOLVE® TRIAD™ Non-Locking Bone Screws Radial Head and Neck Plates

Bone Screws (for use outside the plate)

• 2.0mm EVOLVE® TRIAD™ Non-Locking Bone Screws • 2.5mm EVOLVE® TRIAD™ Cannulated Screws (Fully Threaded)

Implant Selection – Plates There are four different sizes of the EVOLVE® TRIAD™ Radial Head Plates. Their sizes correspond with the most commonly used EVOLVE® Modular Radial Head diameters. In addition to the radial head plates, there are two sizes of radial neck plates. The surgeon should select the plate which best suits the fracture type and best fits the diameter of the radial head and neck. The radial head and radial neck plates feature polyaxial locking screw holes as well as oval slots that may be used to adjust the longitudinal position of the plate and/or used as a compression slot.

Radial Head Plates

20mm

22mm

24mm

26mm

Radial Neck Plates

21mm

25mm

1. Ring D, Jupiter JB, Zilberfarb J. Posterior dislocation of the elbow with fractures of the radial head and coronoid. J Bone Joint Surg Am 2002;84:547–51.

Chapter 1

Device Description

Plate Specifications

Implant Selection – Screws Select the appropriate compatible screw for use with the plate that is chosen. ORTHOLOC® Mini Screw 2.0mm Polaxial Locking

Radial Head and Neck Plates

EVOLVE® TRIAD™ 2.0mm Non-Locking Bone Screw

Round Holes Oval Slots

X X

Fractures that do not require a plate may be fixed using an EVOLVE® TRIAD™ Bone Screw. Diameter (mm)

Description

2.5 mm

EVOLVE® TRIAD™ 2.5mm Cannulated Bone Screw

2.0 mm

ORTHOLOC® Mini Screw Polyaxial Locking

2.0 mm

EVOLVE® TRIAD™ Non-Locking Bone Screw

Type

Thread Length

10-50 - 2mm increment

2.0

Star-8

Fully Threaded

10-30 - 2mm increment 35,40

1.3

Star-7

Fully Threaded

10-30 (2mm incr), 35,40

1.3

Star-7

Fully Bone/ Cannulated Threaded Plate/ Locking

(not for use outside the plate)

Plate/ Bone

Available Lengths Pre-Drill Driver (mm) (mm)

Color Code

Color Coding System The EVOLVE® TRIAD™ System features an instrument color coding system to increase O.R. efficiency. After choosing the appropriate screw, note its color code in the screw caddy. Select the drill and drill guide with the corresponding color coded markings. A black color code on an instrument indicates the instrument is used for lag screw fixation.

Chapter 1

Device Description

2.5mm Caddy

1 6

3 4 2

1. Cleaning Stylet 2. 2.0mm Drill 3. 2.5mm Drill (space for optional overdrill to be added to the set) 4. Countersink for 2.5mm Screws 5. Star-8 Driver 6. 2.5mm Screws

2.0mm Caddy

1 5 7

2 4

Chapter 1

Device Description

1. Screw Gripper 2. 2.0mm Locking Screws 3. 2.0mm Non-Locking Screws 4. 1.3mm Drill 5. 2.0mm Drill (overdrill) 6. Countersink for 2.0 mm Screws 7. Star-7 Straight Driver 8. Star-7 Self Retaining Driver

chapter

Intended Use

EVOLVE® TRIAD™ Fixation System Indications Wright’s EVOLVE® Proline Plus Radial Head and Repair System is a set configuration designed to address radial head fractures. It combines parts of two systems: EVOLVE® Proline and EVOLVE® TRIAD™. Wright’s EVOLVE® TRIAD™ Fixation System is intended for fixation of fractures, osteotomies and non-unions of the olecranon, radius and ulna. The EVOLVE® Proline Plus Radial Head and Repair System excludes two groups from the TRIAD™ system – it does not include the coronoid plates or the 1.5mm screws. The ORTHOLOC® Mini Polyaxial Locking Screws are intended for use with Wright’s plates manufactured from implant grade stainless steel that accept ORTHOLOC® Mini Polyaxial Locking Screws. The EVOLVE® TRIAD™ Bone Screws are indicated for use in bone reconstruction, osteotomy, arthrodesis, joint fusion, fracture repair, and fracture fixation of bones appropriate for the size of the device, including the scapula, long bones (ulna, radius and humerus) and small bones (metacarpals, metatarsals, and phalanges).

Contraindications • Infection • Physiologically or psychologically inadequate patient • Inadequate skin, bone, or neurovascular status • Irreparable tendon system • Possibility for conservative treatment • Growing patients with open epiphyses • Patients with high levels of activity IMPORTANT: Please consult Instructions For Use package inserts 146884 and 146886 for additional risk information.

Chapter 2

Intended Use

EVOLVE® Proline Plus Radial Head and Repair System Wright’s EVOLVE® Proline Plus Radial Head and Repair System is a set configuration designed to address radial head fractures. It combines parts of two systems: EVOLVE® Proline and EVOLVE® TRIAD™. This IFU section is for the radial head prosthesis, while the previous page IFU was for the TRIAD™ plates and screws. The Radial Head Implant is available as a modular, two-piece, intramedullarystemmed implant. The device acts as a spacer in the radio-humeral joint. The Radial Head Implants have been sterilized. A sizing set, supplied non-sterile and not suitable for implantation, is available for proper size determination during surgery.

Indications Use of the Radial Head Implant may be considered for: • Replacement of the radial head for degenerative or post-traumatic disabilities presenting pain, crepitation, and decreased motion at the radio-humeral and/or proximal radioulnar joint with: > joint destruction and/or subluxation > resistance to conservative treatment • Primary replacement after fracture of the radial head. • Symptomatic sequelae after radial head resection. • Revision following failed radial head arthroplasty. Visible on x-ray; and/or resistance to conservative treatment.

Chapter 2

Intended Use

chapter

Preoperative Planning

Undisplaced radial head fractures should be managed non-operatively while displaced radial head fractures should be treated with open reduction and internal fixation if technically feasible. For those cases, the EVOLVE® Proline Plus Radial Head and Repair System can be used (4955KIT1/A/B) as well as the EVOLVE® TRIAD™ Fixation System (4951KIT1/A). Comminuted displaced radial head fractures, which cannot be reconstructed with stable internal fixation, should be managed with radial head excision or prosthetic replacement. In the setting of an associated elbow dislocation, radial head excision without replacement is contraindicated due to valgus instability arising from concomitant injury to the medial collateral ligament of the elbow. The diagnosis of disruption of the medial collateral ligament and/or interosseous membrane is more problematic in patients without an associated elbow or distal radioulnar joint dislocation. In one study, all patients with comminuted radial head fractures without an associated elbow dislocation had insufficiency of the medial collateral ligament or interosseous membrane as documented by stress radiographs.8 Given this high frequency of unrecognized soft tissue injury with comminuted radial head fractures, it is not surprising that some authors recommend that primary prosthetic substitution should be performed in all patients where radial head resection is required. Dr. Graham King and colleagues at St. Joseph’s Health Centre in London, Ontario, Canada, performed a cadaveric study evaluating the ability of radial head implants to stabilize the medial collateral ligament deficient elbow. Their findings showed that metallic implants improved elbow stability as measured by a significant decrease in varus-valgus laxity. Additionally, they found that elbow stability following radial head resection and metallic implant arthroplasty was similar to the stability of an intact radial head in the medial collateral ligament deficient elbow.9 Their laboratory has also demonstrated the kinematics of the elbow are altered following radial head excision even with intact ligaments. Radial head replacement with the EVOLVE® system can restore the kinematics of the elbow similar to that with the native radial head.10 This suggests that routine replacement of the radial head may be beneficial, even in the setting where the ligaments are competent. EVOLVE® Radial Head Replacement is also valuable for the management of reconstructive elbow problems including radial head non-unions and malunions as well as for revision of failed radial head arthroplasty. It is also useful for treating elbow and forearm instability after radial head resection.

8. Davidson PA, Moseley JB, Tullos HS. Radial head fracture: A potentially complex injury. Clinical Orthopaedics and Related Research. 297:224-230, 1993. 9. King GJ, Zarzour ZD, Rath DA, Dunning CE, Patterson SD, Johnson JA. Metallic radial head arthroplasty improves valgus stability of the elbow. Clinical Orthopedics and Related Research 368:114-25, 1999. 10. Beingessner DM, Dunning CE, Gordon KD, Johnson JA, King GJ. The effect of radial head excision and arthroplasty on elbow kinematics and stability. Journal of Bone and joint Surgery. 86A:1730-1739, 2004.

Chapter 3

Preoperative Planning

chapter

Surgical Technique

EVOLVE® Proline Plus Skin Incision Radiographs of the contralateral elbow and both wrists are helpful in preoperative planning, particularly if the radial head has previously been excised. Estimate the radial head and stem sizes needed using the Proline X-ray Template (496XR01). With the patient in either the supine or lateral decubitus position, make a posterior midline longitudinal skin incision just lateral to the tip of the olecranon. Elevate a full thickness lateral flap (fasciocutaneous) on the deep fascia to protect the cutaneous nerves. The posterior midline incision permits access to the medial side of the elbow if repair of the medial collateral ligament is necessary to restore elbow stability. It is also more cosmetic than a laterally-based incision. In patients with isolated injuries to the radial head, a traditional lateral skin incision may be employed. However, first identify and protect the cutaneous nerves which usually cross the incision. | FIGURE 2

Proline X-ray Template (496XR01)

Biceps Brachialis

Lateral Skin Incision

| FIGURE 2 Extensor carpi radialis brevis

Lateral intermuscular septum

Posterior antebrachial cutaneous nerve Brachioradialis

Extensor carpi radialis longus

Triceps

Extensor carpi ulnaris

Triceps tendon

Extensor digitorum communis

Posterior Skin Incision

Chapter 4

Anconeus

Surgical Technique

Lateral Epicondyle

Direct Lateral Dissection Pronate the forearm to move the posterior interosseous nerve more distal and medial during the surgical approach. Split the extensor digitorum communis tendon longitudinally at the midaspect of the radial head and incise the underlying radial collateral and annular ligaments. | FIGURE 3 Keep dissection anterior to the lateral ulnar collateral ligament to prevent the development of posterolateral rotatory instability. If additional exposure is needed, elevate the humeral origin of the radial collateral ligament and the overlying extensor muscles anteriorly off the lateral epicondyle and lateral supracondylar ridge. In the unusual circumstance where further exposure is required, consider releasing the posterior component of the lateral collateral ligament (including the lateral ulnar collateral ligament). However, careful ligament repair is required at the end of the procedure in order to restore the varus and posterolateral rotatory stability of the elbow. In many circumstances, the radial head is easily visualized after opening the subcutaneous tissue due to avulsion of the lateral collateral ligament and common extensor muscles from the lateral epicondyle during the injury.

| FIGURE 3

Extensor Carpi Radialis Longusa

Radial collateral ligament

Triceps

Extensor Digitorum Communis Extensor Carpi Ulnaris Anconeus

Chapter 4

Surgical Technique

Resection Remove and retain all fragments of the radial head. Using a sagittal saw, resect the remaining radial head at the level of the radial neck fracture, perpendicular to the neck to make a smooth surface for seating the prosthetic radial head. | FIGURE 4 Confirm complete radial head excision with an image intensifier and by reassembling the resected radial head in the Sizing and Assembly Dish (24981005). | FIGURE 5 It is recommended that at least 60% of the native radial neck be in contact with the implant. If not, make the radial neck cut more distal and use a thicker head/stem prosthesis. Copiously irrigate the joint to remove all loose intra-articular debris. Evaluate the capitellum for chondral injuries or osteochondral fractures. Manage associated fractures of the coronoid as indicated prior to radial head replacement. Carefully place a Hohman retractor around the posterior aspect of the proximal radial neck to deliver the radial neck laterally. | FIGURE 6 Avoid placing the retractor anteriorly due to the risk of injury to the posterior interosseous nerve from pressure.

| FIGURE 5

| FIGURE 4

Sizing and Assembly Dish (24981005)

| FIGURE 6

Chapter 4

Surgical Technique

Trial Head Selection

| FIGURE 7

Select the appropriate Trial Head (2499H018-2499H428) diameter based on backtable reassembly of the radial head fragments. For elliptically shaped radial heads, select the minimum rather than the maximum diameter. | FIGURE 7 Pay special attention to replicate the size of the articular dish rather than the outside diameter of the native head. | FIGURE 8 Select the prosthesis height based on the thickness of the flatter articular portion of the native radial head that articulates with the proximal radial ulnar joint. | FIGURE 9 In the setting where the radial head has been previously excised, use the Proline X-ray Template on the contralateral normal radial head to determine the appropriate diameter and height of the radial head implant. If the native radial head is between available implant sizes in diameter or height, downsize the implant in the appropriate dimension.

Stem Broaching Create an opening in the medullary canal using the Starter Awl (24987100). Sequentially ream the radial neck by inserting the Stem Broaches (2498714524987105) to the depth indicators on the Broaches | FIGURE 10 until the Stem Broaches no longer pass easily into the canal due to cortical contact.

depth indicator

| FIGURE 8

| FIGURE 9 | FIGURE 10

Trial Head (2499H018-2499H428)

Chapter 4

Starter Awl (24987100)

Surgical Technique

Stem Broaches (24987145-24987105)

Neck Planing Leave the last stem broach in the canal and remove the handle. Slip the Neck Planer (24981003) over the Stem Broach. | FIGURE 11 Gently rotate the Neck Planer to create a smooth contact surface on the radial neck, perpendicular to the longitudinal axis of the radial neck. | FIGURE 12 Avoid excessive planing as it may increase the height of the stem required. | FIGURE 11

Trial Stem Selection

| FIGURE 12

Select the appropriate Trial Stem (2499S045-2499S495) diameter based on the largest Stem Broach that easily fits in the canal. The Trial Stem should fit into the radial neck | FIGURE 13 without force and have a slightly loose but not sloppy fit in the medullary canal of the radius. Undersizing the Trial Stem diameter by one size, in comparison to the broach diameter, is recommended in most cases to allow for the implant to toggle and precisely conform with the capitellum during range of motion. Select the stem collar height by placing the trial stem into the trial head and comparing the total height with that of the native radial head that was excised. | FIGURE 14

| FIGURE 13

Neck Planer (24981003)

Trial Stem (2499S045-2499S495)

| FIGURE 14 Chapter 4

Surgical Technique

Trial Stem and Head Insertion

| FIGURE 15

Grasp the Trial Stem (2499S045-2499S495) with the Trial Stem Handle (24981002) so that the handle sits below the Trial Head. Insert the Trial Stem into the medullary canal. Screw the Trial Head onto the Trial Head Handle (24981001). Holding the Trial Head Handle in line with the Trial Stem Handle, slide the Trial Head over the Trial Stem platform. | FIGURE 15 Once the Trial Head is completely seated on the Trial Stem platform, rotate the Trial Handles 90º apart | FIGURE 16 to lock the Trial Head and Trial Stem together via a ball plunger connection. | FIGURE 17 If the Trial Handles do not rotate easily, reconfirm that the Trial Head is completely seated on the Trial Stem platform.

90°

| FIGURE 16

| FIGURE 17

Trial Stem (2499S045-2400S495)

Trial Stem Handle (24981002)

Trial Head Handle (24981001)

Chapter 4

Surgical Technique

Validate Trial Sizing Unscrew the Trial Head Handle from the Trial Head and remove the Trial Stem Handle. Reduce the elbow with the trials in place. Verify smooth motion in passive flexion and extension of the elbow and rotation of the forearm. Some translation of the Trial Head relative to the capitellum is normal with forearm rotation. Assess the appropriate implant height by pronating the forearm to compensate for the lateral destabilization induced by the surgical approach or injury. The Trial Head should articulate with the most proximal margin of the proximal radioulnar joint approximately 1mm distal to the coronoid process. NOTE: To reduce the risk of cartilage wear on the capitellum from excessive pressure, avoid overstuffing the radiocapitellar joint with a radial head implant that is too thick. To avoid overstuffing the radial-capitellar joint, use the combined Trial Head and Trial Stem collar height to approximate the height of the native radial head and radial neck portion that was resected, not the gap between the radial neck and the capitellum. There is often a small gap between the Trial Head and Capitellum; particularly in cases with lateral ligament injuries. Do not increase the implant thickness to compensate for the ligament injuries. Repairing the collateral ligaments prior to closure will stabilize the joint.

| FIGURE 18

Use an image intensifier to evaluate ulnar variance at the wrist. An implant that is too thick will have ulnar negative variance and an implant that is too thin will have ulnar positive variance relative to the contralateral wrist. Visualize the medial ulnohumeral joint in an anteroposterior view with an image intensifier to ensure that the joint space is symmetrical. | FIGURE 18 An implant that is too thick will result in varus alignment and a non-parallel medial ulnohumeral joint space that is wider laterally. If the prosthesis is tracking poorly on the capitellum with forearm rotation, trial a smaller stem size to ensure that the articulation of the radial head with the capitellum is controlled by the annular ligament and articular congruency, and not dictated by the motion pathways of the proximal radial shaft. NOTE: A metallic radial head will appear larger on x-ray than the native radial head because it is replacing radiolucent cartilage as well as radiographic bone.

Trial Head and Stem Removal | FIGURE 19

Once optimal sizing has been determined, reattach the Trial Handles to the Trials. Unlock the Trial Head from the Trial Stem by realigning the handles. Remove the Trial Head from the joint space and then remove the Trial Stem. Irrigate the joint thoroughly.

Implant Insertion Using Back Table Implant Assembly Head Implant (496H018-496H428) Stem Implant (496S045-496S495)

In most acute injuries, the proximal radius is sufficiently mobile or the lateral ligaments have been compromised such that the implant can be assembled on the back table and inserted as a monoblock implant. To do this, insert the Stem Implant (496S045-496S495) into the Head Implant (496H018-496H428) and place onto the Sizing and Assembly Dish. Place the appropriately sized Stem Impactor (24981007-24981009) over the stem and strike it firmly three times with a mallet. | FIGURE 19 Insert the assembled implant into the proximal radius by retracting the proximal radius laterally (Figure 6). | FIGURE 6

Stem Impactor (24981007-24981009)

Chapter 4

Surgical Technique

Implant Insertion Using In Situ Assembly When the lateral ligaments are intact in acute injuries and in cases of late reconstruction, insertion of the assembled implant may not be possible due to insufficient mobility of the proximal radius. In these settings, the two components of the implant should be inserted separately and then coupled in situ using the supplied locker. While retracting the proximal radius with a retractor, insert the Stem Implant into the medullary canal. It should slide in easily. | FIGURE 20 Using finger control, slide the Head Implant into the joint space with the Head Implant female taper over the Stem Implant male taper. | FIGURE 21

Locker Assembly

| FIGURE 20

Assemble the Locker by first inserting the Stem Paddle Post (24991001) into the Locker Body (24991000). Screw the Locker Assembly Knob (24982005) onto the Stem Paddle Post. Insert the appropriately sized Head Paddle (2499101824991028) into the jaw on the Locker Body. Insert the appropriately sized Stem Paddle (24991045-24991095) into the jaw on the Stem Paddle Post. | FIGURE 22 NOTE: The Locker is the only recommended device for in situ assembly. A tamp and/or mallet will not generate enough force to adequately secure the Morse taper and disassociation may occur. NOTE: "Locker” system not included in Proline Plus – must be requested separately through sales representative. 2499KIT2 E

| FIGURE 21

Stem Paddle

- 6 Sizes

LOCKER ASSEMBLY 1. Insert Stem Paddle Post (A) into Locker Body (B)

Stem Paddle Post

2. Screw Locker Assembly Knob (C) onto Stem Paddle Post (A) Stem Paddle Post (24991001)

Locker Body (24991000)

3. Snap Head Paddle (D) into Locker Body (B) 4. Snap Stem Paddle (E) into Stem Paddle Post (A)

Head Paddle

- 6 Sizes

Locker Body

Locker Assembly Knob (24982005)

Head Paddle (24991018-24991028)

| FIGURE 22 C

Locker Assembly Knob

Stem Paddle (24991045-24991095)

Chapter 4

Surgical Technique

Closure Following radial head replacement, repair the lateral collateral ligament and extensor muscle origins back to the lateral condyle. If the posterior half of the lateral collateral ligament is still attached to the lateral epicondyle, repair the anterior half of the lateral collateral ligament (the annular ligament and radial collateral ligament) and extensor muscles to the posterior half using interrupted absorbable sutures. | FIGURE 23 If the lateral collateral ligament and extensor origin have been completely detached either by the injury or surgical exposure, securely repair them to the lateral epicondyle using drill holes through bone and non-absorbable sutures or suture anchors. Place a single drill hole at the axis of motion (the centre of the arc of curvature of the capitellum) and two drill holes placed anterior and posterior to the lateral supracondylar ridge. Employ a locking (Krackow) suture technique to gain a secure hold of the lateral collateral ligament and common extensor muscle fascia. Pull the ligament sutures into the holes drilled in the distal humerus using suture retrievers. Pronate the forearm and avoid varus forces while tensioning the sutures prior to tying. Leave the knots anterior or posterior to the lateral supracondylar ridge to avoid prominence. Following replacement arthroplasty and lateral soft tissue closure, place the elbow through an arc of flexion-extension while carefully evaluating for elbow stability in pronation, neutral, and supination. Pronation is generally beneficial if the lateral ligaments are deficient, supination if the medial ligaments are deficient and neutral position if both sides have been injured. In patients who have an associated elbow dislocation, perform additional repair of the medial collateral ligament and flexor pronator origin if the elbow subluxates at 40° or more of flexion. After tourniquet deflation and secure hemostasis, the subcutaneous tissues and skin are closed in layers.

Radial collateral ligament

Extensor digitorum communis

Extensor carpi ulnaris

| FIGURE 23

Chapter 4

Surgical Technique

Explant Information If the removal of the implant is required due to revision or failure of the device, the surgeon should contact the manufacturer using the contact information located on the back cover of this surgical technique to receive instructions for returning the explanted device to the manufacturer for investigation.

Postoperative Management The recommended Post-Op Care varies primarily according to ligament competency.11,12 1. MCL and LCL Competent a. Splint elbow in extension and forearm in neutral b. Unrestricted active elbow motion permitted postoperatively c. Night-time resting extension splint may assist in gaining terminal extension

Lateral view at 2 years post-op

2. MCL Competent but LCL Incompetent a. Splint elbow at 90º with forearm pronated b. Active flexion-extension performed with forearm pronated c. Prosupination performed with elbow in flexion d. Avoid extension in supination for six weeks 3. MCL Incompetent and LCL Competent a. Splint elbow at 90º with forearm supinated b. Active flexion-extension performed with forearm supinated c. Prosupination performed with elbow in flexion d. Avoid extension in pronation for six weeks 4. MCL and LCL Incompetent a. Splint elbow at 90º with forearm in neutral b. Active flexion-extension performed with forearm in neutral rotation c. Prosupination performed with elbow in flexion d. Gradually allow increasing extension as stability improves with healing over six weeks

AP view at 2 years post-op

5. General Rehabilitation a. No passive stretching for six weeks to avoid heterotopic ossification. b. Strengthening exercises commence six to eight weeks postoperatively c. Night-time extension splint may be useful to regain terminal elbow extension. d. Prescribing indomethacin may reduce the incidence of heterotopic bone formation.

11. Armstrong AD, Dunning CE, Faber KJ, Duck TR, Johnson JA, King GJW: Rehabilitation of the medial collateral ligament-deficient elbow: An in vitro biomechanical study. J Hand Surg 25A:1051-1057, 2000. 12. Dunning CE, Zarzour ADS, Patterson SD, Johnson JA, King GJW: Muscle forces and pronation stabilize the lateral ligament deficient elbow. Clin Orthop & Related Research 388:118-124, 2001.

Chapter 4

Surgical Technique

Previous Page Next Page