ORTHOSPHERE Spherical Interpositional Implant

Transcription

1 ORTHOSPHERE Spherical Interpositional Implant

2 ORTHOSPHERE spherical interpositional implant surgical technique presented by J. H. CALANDRUCCIO, MD M. T. JOBE, MD 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 and experience. Prior to use of the system, the surgeon should refer to the product package insert for complete warnings, precautions, indications, contraindications and adverse effects. Package inserts are also available by contacting Wright.

3 ORTHOSPHERE spherical interpositional ARTHROPLASTY as described by J.H. Calandruccio, MD and M.T. Jobe, MD general PRECAUTIONS Proper surgical techniques are necessarily the responsibility of the medical professional. The following guidelines are furnished only as recommended techniques. Each surgeon must evaluate the appropriateness of the techniques based on his or her own medical training and expertise. INTRODUCTION Hand function is inseparably linked to the condition of the thumb carpometacarpal joint. Although fractures, ligament injuries, and rheumatologic processes may damage this important articulation, basal joint arthroplasty is most often performed to relieve pain and increase motion in joints damaged by osteoarthritis 1. The ORTHOSPHERE carpometacarpal (CMC) implant is a spherical interpositional device fabricated from yttria-stabilized zirconia and is used to replace the symptomatic joint between the first metacarpal and the trapezium. INDICATIONS The indications for the ORTHOSPHERE implant include: Osteoarthritis Post-traumatic arthritis INSTRUMENT SET The ORTHOSPHERE Instrument Set includes 6 oscillating burrs, 6 implant sizers, 2 rotary starter burrs, insertion forceps, burr cleaning brush, and power adapters. CATALOG # SPHERE SIZE mm mm mm mm mm mm one

4 CONSIDERATIONS The ORTHOSPHERE implant may be considered for: Impairment of the thumb basal joint with localized CMC bony changes Localized pain and palpable crepitation during circumduction movement with axial compression of the involved thumb ( grind test ) Decreased motion, decreased pinch, and decreased grip strength X-ray evidence of arthritic changes isolated to the trapeziometacarpal joint Pre-Op design RATIONALE The implant is a simple sphere which, as a dynamic spacer, maintains thumb column height. The thumb CMC joint anatomy has been described as a concavo-convex, or saddle-shaped, bearing surface which allows the joint to flex, extend, abduct, adduct, circumduct, and pronate and supinate on a limited basis 1. Unlike other treatment modalities for the thumb CMC joint, this device does not require complete excision of the trapezium, but relies on the structure of the trapezium and base of the metacarpal to provide stability to the replaced joint surfaces. Once positioned, the spherical implant acts as a dynamic spacer between the metacarpal and trapezium. Placement of the device requires limited surgical dissection and thus preserves the soft tissue structures around the joint, and leaves the scapho-trapezium joint undisturbed. Very little bone is excised to prepare for implant placement, which is advantageous because it allows revision to other joint arthroplasties or excisional treatments. The limited dissection and excision may allow quicker surgical recovery than more invasive treatments requiring greater exposure and bone removal. Post-Op two

5 FIGURE 1 DRL APL FIGURE 2A Dorsal view IML POL SURGICAL TECHNIQUE FOR SPHERICAL INTERPOSITIONAL ARTHROPLASTY (ORTHOSPHERE ) STEP 1 - PATIENT POSITIONING AND ANESTHESIA The patient is placed supine on the operating table with the arm abducted 90 over an arm table. A tourniquet is applied and the patient s arm is prepared and draped out in the usual sterile manner. Either Bier block, axillary block, or general anesthesia is preferred. STEP 2 - ANATOMY AND SURGICAL APPROACH Approach to the 1st carpometacarpal (CMC) joint can be safely made by an incision about the dorsoradial base of the thumb. FIGURE 1 Make a longitudinal incision along the 1st extensor compartment centered over the thumb CMC joint. Sensory branches in this area should be identified and protected. The concavo-convex mating articular surfaces of the thumb CMC joint are stabilized by a ring of specialized ligamentous supports. These ligaments are important to stabilization of the CMC joint. FIGURE 2A and FIGURE 2B Preservation and repair of this soft tissue ring is important to the success of this procedure. The interval between the abductor pollicis longus (APL) and extensor pollicis brevis (EPB) affords excellent exposure to the 1st CMC joint. The APL inserts into the thumb metacarpal base dorsoradially, just palmar to the dorsoradial ligament (DRL). The radial artery courses over the trapezial base dorsally and should be located and protected. An 8mm wide capsular flap based on the trapezium is sharply dissected from the metacarpal base. FIGURE 3 This dissection begins distally at the metacarpal insertion of the APL and then carried proximally parallel to the dorsal border of the APL. DRL APL APL EPB FIGURE 2B Volar view FIGURE 3 three

6 STEP 3 - DISTAL TRAPEZIAL RESECTION An oscillating saw is used to resect the distal mm of trapezial surface. FIGURE 4 This cut is made to remove the trapezial dome and joint debris including the intermetacarpal osteophyte and dorsal and volar ridge of the trapezium. Remove the distal trapezium in wafer thin sections to insure adequate trapezial bone stock for the spherical implant. Take care to avoid injury to the FCR tendon by completing the trapezoid cut with an osteotome using a prying motion. Using the oscillating saw, resect a thin portion of subchondral bone to level the metacarpal base. FIGURE 4 FIGURE 5 FIGURE 6 STEP 4 - GAP WIDTH AND SPHERE SEAT PREPARATION The CMC joint space is irrigated free of debris to allow complete visualization of the metacarpal base and distal trapezial surface. Measure the CMC gap width with the implant sizer FIGURE 5 to determine probable implant size. The sizer should insert into the CMC gap width with minimal resistance. The gap is usually 3-4mm. Use the largest sizer which easily fits into the space, allowing a 2-3mm rim of bone around the implant in both the MC and Trapezium. A rotary burr (3-5mm diameter) is used to create rough partial recesses in the opposing CMC surfaces. The trapezial recess is initiated first. FIGURE 6 Begin the spherical recess slightly volar to the center of the cut trapezial surface. Make a centralized metacarpal base recess with the rotary burr. FIGURE 7 Enlarge the recesses to approximately 7-8mm in diameter and 3mm deep, prior to final recess preparation with the oscillating semispherical burrs. FIGURE 8A FIGURE 8A FIGURE 7 four

7 The desired implant diameter will typically be 3 times the prepared gap width. Use of sequentially larger oscillating burrs will permit necessary adjustments in recess preparation. FIGURE 8B The oscillating burrs should be completely seated in the trapezium since trapezial depth is important to insure implant stability. Keep the dorsal and radial trapezial rims at least 2mm in width. FIGURE 8B STEP 5 - TRIAL SIZING The sizer for the desired implant is placed into the partial spherical recess spaces. FIGURE 9 If the sizer cannot be rotated into position then deeper seating will be required. Ensure that the trapezial depth is at least 1/3 the diameter of the spherical portion of the sizer before reburring the metacarpal base. Appropriate recesses are obtained when the trial sizer permits 40 of extension-flexion and abductionadduction arcs. FIGURE 10A and FIGURE 10B FIGURE 9 FIGURE 10A Extension-Flexion FIGURE 10B Abduction-Adduction five

8 STEP 6 - SPHERE IMPLANTATION The implant is grasped with the inserter FIGURE 11 and with firm steady pressure the spherical implant will suddenly jump into the prepared recesses. FIGURE 12 The thumb CMC motion is rechecked. FIGURE 11 STEP 7 - CAPSULAR CLOSURE After wound irrigation the DRL is reapproximated to the APL insertion. The remainder of the capsule is approximated with non-absorbable 3-0 or 4-0 braided suture. FIGURE 13 Implant positioning and seating is verified with intraoperative plain roentgenograms of the 1st CMC joint. FIGURE 12 FIGURE 13 post-operative CARE A thumb spica splint is worn continuously for 2 weeks. A removeable thumb spica splint is worn for 4 weeks and removed for skincare and bathing. At six weeks post-op more aggressive use of the hand is encouraged. Unrestricted activity is allowed 8-12 weeks post-op. Hand therapy may be required to regain motion and strength. six

9 other CONSIDERATIONS In using joint prostheses, the surgeon should be aware of the following: A. The correct selection of the prosthesis is extremely important. The potential for success in joint replacement is increased by selection of the proper size, shape and design of the prosthesis. B. In selecting patients for the ORTHOSPHERE implant, the following factors can be critical to the eventual success of the procedure: 1. PATIENT S OCCUPATION OR ACTIVITY If the patient is involved in an occupation or activity which includes substantial lifting or muscle strain, the resultant forces can cause failure of function, the device or both. The prosthesis may not restore function to the level expected with a normal healthy joint. 2. SENILITY, MENTAL ILLNESS, OR ALCOHOLISM These conditions among others may cause the patient to ignore certain necessary limitations and precautions in the use of the prosthesis, leading to failure or other complications. 3. FOREIGN BODY SENSITIVITY Where material sensitivity is suspected, appropriate tests should be made prior to material selection or implantation. CONTRAINDICATIONS Overt infection Distant foci of infections (which may cause hematogenous spread to the implant site) Skeletally immature patients (i.e. growing patients with open epiphyses) Inadequate bone to support the implant Each patient must be evaluated by the surgeon to determine the risk/benefit relationship. seven

10 *WHEN USING POWER ADAPTERS: Adapter is compatible with the following saws: Stryker Micro 31 Zimmer /Hall Micro 100 Micro 100XL Micro 160 Micro E Adapter is compatible with the following saws: Stryker Command 2 TPS. NOTE Centers not equipped with the appropriate hand power may order a loaner set (TAVA KIT1) from Wright Medical Technology. 1 Calandruccio, JH and Jobe, MT, Arthroplasty of the Thumb Carpometacarpal Joint, Seminars in Arthroplasty, vol. 8, no. 2, 1997, pp CAUTION Federal Law (U.S.) restricts this device to the sale, distribution, and use by or on the order of a physician. eight

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