Motec. Basal Thumb Joint Prosthesis

Transcription

1 Motec Basal Thumb Joint Prosthesis

2 Motec Basal Thumb Joint Prosthesis The Motec Basal Thumb Prosthesis has been designed specifically for high demand patients, with the objective to provide a strong, stable, mobile and pain free thumb while minimizing the risk of luxation, loosening and osteolysis. Fixation is achieved by threaded implants made of titanium alloy, blasted and coated with Bonit, which promotes osseointegration between titanium oxide and bone. The articulation is modular and can be configured depending on surgeon and patient preference, with a CoCrMo head articulating either on carbon reinforced PEEK Motis TM or polyethylene. The system also features a cemented polyethylene salvage cup. Each component is available in different sizes, to allow firm seating and close replication of the patient s normal range of motion. Indications The system is indicated in cases of pain, instability or reduced motion of the basal thumb joint caused by rheumatoid arthritis, primary osteoarthritis and secondary arthritis. The patient must be at least 15 years of age. 2

3 Features and benefits The Motec Basal Thumb Joint Prosthesis has the following features and benefits: l Modular design l State-of-the-art articulation l Optimized short term fixation through threaded implants l Optimized long term fixation and osseointegration l Fully compatible salvage procedure Patent number SE C2 Application number PM PC 00 3

4 Modular design Maximum flexibility The Motec Basal Thumb Joint Prosthesis is completely modular in its design to give the surgeon maximum flexibility in matching the anatomy of the patient. l The primary fixation in bone is achieved by threaded implants which are available in different sizes. Metacarpal Threaded Implant is available in five different lengths and two XL sizes. l The head component is available with several different neck lengths to enable fine tuning of the joint tension. l The cup component is available in different materials depending on surgeon and patient preference. See pages for details. l In case of loosening of the Trapezium Threaded Implant, a cemented Salvage Cup is also available. See page 12 for details. The Metacarpal Head Implant is available in five different length to allow the surgeon to adjust the tension of the joint. The Trapezium Threaded Implant is available in three different sizes to allow matching of the trapezial anatomy. The Trapezium Cup is available in CFR-PEEK, both flat and lateralized, as well as in UHMWPE.The system also includes a UHMWPE salvage cup. 4

5 The Lateralized Trapezium Cup A lateralized Trapezium CFR-PEEK Cup can be used to counteract the forces that cause luxation in cases where the Trapezium Threaded Implant is angulated radially. The wall is placed dorsoradially. Standard cup The Trapezium Threaded Implant has been angulated radially in combination with a standard Trapezium Cup. Lateralized cup The forces that cause luxation can be counteracted by placing the wall of the Lateralized Trapezium Cup facing dorsoradially. 5

6 Optimized short term fixation Trapezium Threaded Implant l Immediate primary fixation is achieved by the threads of the Trapezium Threaded Implants. l Closely replicating the anatomical center of rotation reducing the bending moment during load. l Wide subchondral bone fixation. l A curved collar prevents the Trapezium Threaded Implant from pivoting sideways or sinking. l The Trapezium Threaded Implants are available in 7, 8.5 and 10 mm lengths, maximizing fixation through the trapezium bone. (Ref. 12) Countersinked cup to reduce bending forces. Holes in the collar allow additional bone ingrowth. The threaded collar engages into subchondral bone, which enhances the fixation while also preventing stripping of the threads. Self-cutting flutes. Curved collar to absorb forces that cause loosening and promote bone formation. The core has a conical shape to evenly distribute forces into cancellous bone, thereby promoting bone formation. Rounded tip to distribute the forces into the subchondral bone. Threads engage into the cancellous bone of the trapezium. 6

7 Metacarpal Threaded Implant l The threads of the conical Metacarpal Threaded Implant engage into the cortical bone of the intramedullary canal, preventing the implant from sinking. l Metacarpal Threaded Implants are available in 20 mm, 24 mm, 28 mm, 32 mm and 36 mm lengths, maximising fixation through the metacarpal bone. l XL Metacarpal Threaded Implants are available in 32 and 36 mm lengths with deeper threads for patients with wide bone channels or severely osteoporotic bone. l Metacarpal Drill core diameter matches the core diameter of all Metacarpal Threaded Implants. Rounded tip to reduce stress. Non-threaded portion to prevent fractures at the isthmus. Cortical bone fixation. Conical shape to evenly distribute the forces into the cancellous and the cortical bone, thereby promoting bone formation. Threads engage into the cancellous bone of the metacarpal. 7

8 Optimized long term fixation and osseointegration l Optimal blasting of titanium alloy implants improves long term fixation and osseointegration (Ref. 3, 10). The titanium surface is blasted with extra pure Al2O3 using a specific technique and to a specific roughness value to maximize the bone ingrowth. l The titanium alloy threaded implants are coated with Bonit, a resorbable calcium phosphate combination with proven osteoconductive properties, improving long term fixation. The implants are coated with a Bonit layer of μm. Total stability Reduced stability dip Total stability Primary stability (old bone) Stability dip Secondary stability (new bone) Primary stability (old bone) Secondary stability (new bone) Without Bonit With Bonit Without Bonit there would be a significant reduction in stability 2-5 weeks postoperatively. This dip coincides with the release of the plaster, thereby increasing the risk of loosening. Bonit promotes early formation of new bone, thereby reducing the risk of loosening. 8 Bonit is a registered trademark of DOT GmbH.

9 In vivo biomechanical comparison of Bonit versus Hydroxyapatite Titanium screws coated with Bonit and screws coated with hydroxyapatite (HA) were implanted in the proximal tibia of a rabbit, for the purpose of comparing the increase of fixation over time. The fixation of the Bonit coated screws increased significantly over time (6 to 12 to 52 weeks) whereas the screws coated with HA showed no increase in fixation after 6 weeks. After 52 weeks, the Bonit layer was fully resorbed (Ref. 1-2). Implant in black and bone in purple. Bonit 6 weeks 12 weeks 52 weeks The Bonit layer is partly resorbed. The Bonit layer is no longer visible. The Bonit layer is fully resorbed. Osseointegration has taken place between the titanium oxide layer and bone. HA coating 52 weeks In contrast to the fully resorbable Bonit, the HA-layer and particles are loosening from the titanium surface. Giant cell, macrophages are visible. Problems with long term fixation using HA coating on implants have also been shown in a thesis by M. Røkkum (Ref. 11). 9

10 State-of-the-art articulation Metal on carbon fiber reinforced PEEK The Metacarpal Head is made from CoCrMo, and the Trapezium Cup is made from carbon fiber reinforced polyetheretherketone (PEEK Motis). PEEK Motis has been specifically developed for bearing applications against hard counterfaces, such as CoCrMo. (Ref. 5-9) The system also includes a Trapezium Cup made from UHMWPE as a secondary option. MOTIS - HC CoCrMo UHMWPE - CoCrMo Pin-on-plate screening of polymer against hard counterface combinations. Source: Invibio Biomaterial Solutions CFR-PEEK represents an alternative load-bearing material because of its superior mechanical and chemical behaviour without any increased biological activity of the wear particles, compared with a standard load-bearing material. The Trapezium Cup is made from carbon reinforced PEEK Motis, specifically developed for bearing applications against hard counterfaces. Utzschneider S, Becker F, Grupp TM, Sievers B, Paulus A, Gottschalk O, Jansson V. Inflammatory response against different carbon fiberreinforced PEEK wear particles compared with UHMWPE in vivo. Acta Biomater Nov;6(11): Motis is a trademark of Invibio Biomaterial Solutions. 10

11 Benefits of PEEK Motis l Exceptional wear performance supported by research and published data l Extensive testing to ISO standards demonstrates biocompatibility and biostability for use in long term implant applications l The thin components allows preservation of bone l Reduced stress shielding and improved stress distribution l An alternative to metal-on-metal combinations, which eliminates metal ion concerns l Demonstrated resistance to gamma sterilization (does not become brittle over time like polyethylene) 11

12 Fully compatible salvage procedure Trapezium Salvage Cup If fixation with the Trapezium Threaded Implant is unsuccessful, a cemented Trapezium Salvage Cup can be used as a salvage procedure. Note: A surgical manual for the cementation of the PE-cup can be obtained from Swemac. The Trapezium Salvage Cup is fully compatible with the Metacarpal Heads. A Trapezium Salvage Cup has been introduced as a secondary procedure. The cement has filled all the cavities between the Trapezium Salvage Cup and the trapezium bone. 12

13 Case 1 Case 2 Male 54 years old. CMC-1 Severe pain, Pre-operative. Female 59 years old. CMC-1 Severe pain, Pre-Operative. Post-operative Post-operative 14 months post-operative. No pain, full ROM and good grip. Implants: 36 mm Metacarpal Threaded Implant 8,5 mm Trapezium Threaded Implant 12 months post-operative. No pain, full ROM and good grip. Implants: 36 mm Metacarpal Threaded Implant 7 mm Trapezium Threaded Implant 13

14 References Articles 1. Reigstad O, Franke-Stenport V, Johansson CB, Wennerberg A, Røkkum M, Reigstad A. Improved bone ingrowth and fixation with a thin calcium phosphate coating intended for complete resorption. J Biomed Mater Res B Appl Biomater Oct;83(1): Reigstad O, Johansson C, Stenport V, Wennerberg A, Reigstad A, Røkkum M. Different patterns of bone fixation with hydroxyapatite and resorbable CaP coatings in the rabbit tibia at 6, 12, and 52 weeks. J Biomed Mater Res B Appl Biomater Oct;99(1): Wennerberg A, Albrektsson T. Effects of titanium surface topography on bone integration: a systematic review. Clin. Oral Implats Res Sep; 20 suppl. 4: Ingham E, Fisher J. Biological reactions to wear debris in total joint replacement. Proc Inst Mech Eng H. 2000;214(1): Review. 5. Scholes SC, Unsworth A. Pitch-based carbon-fibrereinforced poly (ether-ether-ketone) OPTIMA assessed as a bearing material in a mobile bearing unicondylar knee joint. Proc Inst Mech Eng H Jan;223(1): Utzschneider S, Becker F, Grupp TM, Sievers B, Paulus A, Gottschalk O, Jansson V. Inflammatory response against different carbon fiber-reinforced PEEK wear particles compared with UHMWPE in vivo. Acta Biomater Nov;6(11): Scholes SC, Unsworth A. Wear studies on the likely performance of CFR-PEEK/CoCrMo for use as artificial joint bearing materials. J Mater Sci Mater Med Jan;20(1): Kabir K, Schwiesau J, Burger C, Pflugmacher R, Grupp T, Wirtz DC. Comparison of Biological Response to UHMWPE and CFR-PEEK Particles in Epidural Space. Universitätsklinikum Bonn, Department for Orthopaedics and Trauma Surgery, Bonn, Germany, Aesculap AG Research & Development, Tuttlingen, Germany Grupp TM, Utzschneider S, Schröder C, Schwiesau J, Fritz B, Maas A, Blömer W, Jansson V. Biotribology of alternative bearing materials for unicompartmental knee arthroplasty. Acta Biomater Sep;6(9): Erratum in: Acta Biomater Apr;8(4):1659. Theses 10. Wennerberg A. On surface roughness and implant incorporation. Department of Biomaterial/Handicap Research, Göteborg, Sweden Røkkum M. On Late Complications With Ha Coated Hip Arthroplasties. Department of Biomaterials/Handicap Research, Institute for Surgical Sciences, Faculty of Medicine, University of Göteborg, Göteborg, Sweden and Orthopaedie University Clinic, National Hospital, Oslo, Norway, Göteborg Internal document 12. Measuring of the trapezium bone in 18 human cadavers and 17 patients with osteoarthritis. Swemac Innovation: Motec CMC validation , and

15 Surgical technique Indications The system is indicated in cases of pain, instability or reduced motion of the basal thumb joint caused by: l Rheumatoid arthritis l Degenerative arthritis (osteoarthritis) l Post-traumatic arthritis (secondary arthritis) after failed treatment of: Fracture of the first metacarpal Fracture of the trapezium Contraindications The physician s education, training and professional judgement must be relied upon to choose the most appropriate device and treatment. Conditions presenting an increased risk of failure include: l Previous open fracture or infection in the joint. Patient positioning The patient is placed supine on the operating table with the arm abducted 90 degrees over an arm table. A tourniquet is applied and inflated. The patients arm is prepared and draped in the usual sterile manner. Anaesthesia and antibiotics Either axillary block or general anaesthesia is recommended. Preoperative antibiotics are recommended. Pre-operative planning It is recommended as an important part of the preoperative planning process that the surgeon should be familiar with the anatomy of the carpal area with special attention to the neuromuscular system. l Physical interference with another prosthesis during implantation or use. l Inadequate skin, bone or neurovascular status. l Irreparable tendon system. l Inadequate bone stock or soft tissue coverage. l Any mental or neuromuscular disorder which would create an unacceptable risk or complication during the postoperative care. Branches of superficial radial nerve l Other medical or surgical conditions which would preclude the potential benefit of surgery. Dorsal branch of radial artery Abductor pollicis longus Extensor pollicis longus Extensor pollicis brevis 15

16 Optimal implant position The volar lip and the ulnar prominence have been removed. They can act as a lever and cause dislocations. The threads of the conical metacarpal threaded implant engage into the cortical bone of the intramedullary canal. The tip of the metacarpal threaded implant is in the centre of the bone and does not penetrate the MCP joint. A 2-4 mm resection of the metacarpal base. The trapezium threaded implant is in the centre of the trapezium bone. The metacarpal threaded implant is flush with the cut surface of the metacarpal bone. The distance from the tip of the proximal end of the trapezium implant and the joint surface should not be shorter than 1.5 mm. Subchondral bone fixation. Note! The following images are from a cadaver specimen. 16

17 1. Make incision 2. Metacarpal base resection A dorsoradial approach centred on the trapeziometacarpal articulation is used. Branches of the superficial radial nerve lie in the subcutaneous fat layer and should be carefully protected. The interval between the abductor pollicis longus and extensor pollicis brevis is used to gain access to the dorsal capsule. The carpometacarpal joint is identified. A 2-4 mm resection of the metacarpal base is performed using an oscillating saw. The bone cut is performed perpendicular to the metacarpal axis. Sharply divide the capsule longitudinally and elevate the adherent soft tissue envelope from the base of the first metacarpal, exposing the trapeziometacarpal joint. The volar lip and the ulnar prominence are then removed. They can act as levers and cause dislocation after the metacarpal has been realigned with the implant. A 360 degree subperiosteal circumferential dissection of the proximal part of the metacarpal is performed in order to facilitate access to the trapezium and to release any adduction contractures. Metacarpal bone after final resection. 17

18 3. Drilling and measuring of the metacarpal 4. Insertion of the Metacarpal Threaded Implant The Metacarpal Drill is inserted down the center of the medullary canal. Its conical shape will automatically align with the axis of the canal. Drilling is carried out by hand under image intensification. When resistance from the cortical bone is felt, the proper insertion depth has been reached. If no cortical resistance is felt, a wider XL Metacarpal Threaded Implant should be used. The wider XL Metacarpal Threaded Implants are only available in 32 and 36 mm length. The chosen Metacarpal Threaded Implant is inserted until its edge is flush with the cut surface. Insertion is carried out by hand only. Avoid touching the implant surface. Use a sterile cloth to avoid contact with the patient s skin and avoid touching the implant with surgical gloves. Use the screwdriver to pick up the implant from the sterile packaging. Be sure not to penetrate the MCP-joint and do not drill further than 36 mm as that is the longest Metacarpal Threaded Implant available. Drill depth is taken directly from the measurements on the drill s cutting flutes. The Metacarpal Threaded Implant is flush with the cut surface of the metacarpal bone. The metacarpal bone is prepared and ready for insertion of the Metacarpal Threaded Implant. The Metacarpal Threaded Implant should always be implanted at this stage, this will minimize any possible damage to the bone during the preparation of the trapezium. 18 Note: Try to avoid touching the implants with your fingers!

19 5. Preparation of the trapezium 6. Orientation of the Guide Wire in the trapezium Reference line A small Hohman retractor is used to pull the metacarpal volarly and ulnarly allowing access to the trapezium. To evaluate the true trapezial joint surface, all osteophytes must be removed. ~20 of palmar abduction The positioning of the Guide Wire in the trapezium is the most critical step in the whole procedure. To ensure proper orientation of the Guide Wire, it is important to have a true A/P and lateral view. Using the second metacarpal as a reference, the Guide Wire is inserted in approximately of palmar abduction and of radial abduction. Position the tip of the Guide Wire at the center of the trapezium. ~15 of radial abduction Reference line 19

20 7. Insertion of the Guide Wire 8. Measuring with the Measuring Sleeve Reference line Laser lines indicate drilling depth. The Guide Wire is advanced to the first laser mark. Check the insertion angle, if incorrect remove the wire and re-introduce it at the correct angle. Using image intensification, the Guide Wire is now driven to within 1.5 mm of the subchondral bone. If the wire depth corresponds exactly to one of the 3 laser marks 7 mm, 8.5 mm or 10 mm then that is the size of drill selected (the depth can also be double-checked by using the Measuring Sleeve as described in the following section). 10 The Measuring Sleeve is used when the depth cannot be determined exactly from the Guide Wire. Slide the sleeve over the Guide Wire until it rests against the trapezium. The depth is read off the scale at the end of the Guide Wire. The Trapezium Threaded Implant is available in 3 sizes: 7 mm, 8.5 mm and 10 mm. Downsize by 1.5 mm if the Guide Wire has been advanced all the way into subchondral bone. If between sizes, choose the smaller size. Once the depth is determined, the Guide Wire is advanced into the subchondral bone. This will help prevent the Guide Wire from spinning during drilling. 20

21 9. Drilling the trapezium 10. Insertion of the Trapezium Threaded Implant Introduce the appropriate Cannulated Trapezium Stop Drill over the Guide Wire and drill until the drill is seated flush with the trapezium. If there are any prominent ridges on the surface of the trapezium, use an oscillating saw to flatten the surface, taking care not to resect too much cortical bone. Perform additional drilling. Flush the joint with sterile water prior to insertion of the Trapezium Threaded Implant. The appropriate implant is inserted using the Hex Driver Tip and the Driver Handle until the collar of the screw is fully engaged in the cortical bone of the trapezium. Forcing the trapezium implant further into the bone may compromise fixation and strip the bone. The Trapezium Threaded Implant is fully seated when the collar engages in the cortical bone of the trapezium. Remove both the Guide Wire and the Cannulated Trapezium Stop Drill. Check the position of the implant under image intensification (the cartilage is not visible under image intensification). Note: insert the Trapezium Threaded Implant slowly, to let the bone stretch properly. 21

22 11. Insertion of the Trapezium Cup 12. Determining the appropriate Metacarpal Head length Ensure the internal Morse cone of the Trapezium Threaded Implant is washed out before inserting the Trapezium Cup. Use the Cup Inserter together with the Cup and Head Forceps to insert the Trapezium Cup into the Trapezium Threaded Implant. There is an increased risk of luxation if the Trapezium Threaded Implant is angulated radially. In such a case, a Lateralized Trapezium Cup can be inserted with the wall facing dorsoradially. This will reduce the risk of luxation. To determine the neck length, you must start by inserting the shortest Metacarpal Head Trial. Increase the trial length until the right tension has been achieved. The Impactor should not be used with the trials. When pulling the thumb, the Metacarpal Head Trial should only just lift from the bottom of the cup. If one size up feels too tight, or if one size down feels too loose, it is possible to adjust the Metacarpal Threaded Implant slightly by introducing it further into the bone. Keep in mind that tension will increase when closing the capsule. The Metacarpal Head Trial is removed once the correct neck length has been determined. When the cup is in position, push the Cup Inserter gently. The cup will snap into position, ensuring firm seating. 22

23 13. Insertion of the Metacarpal Head 14. Final reduction Make sure that the internal Morse cone of the Metacarpal Threaded Implant is clean. Introduce the Metacarpal Head into the Metacarpal Threaded Implant. The joint is reduced and stability and range of motion is evaluated under image intensification. Haemostasis is obtained after releasing the tourniquet. When the Metacarpal Head is in position, tap the Impactor gently to ensure firm seating. 23

24 15. Closure Postoperative care Carefully close the capsule with absorbable sutures. 0-3 weeks: A postoperative plaster is applied to immobilize the first CMC, the first MCP and the STT. It is important that the plaster is applied with the first metacarpal in palmar and radial abduction and the MCP joint in slight flexion. Motion is allowed in the radiocarpal joint, the finger joints and the thumb IP-joints. Close the skin in the normal fashion weeks: Active motion without load is started with a removable protective resting splint weeks: The patient is allowed to do lighter tasks, gradually increasing active motion with load. After a few weeks, the patient does not need to wear the protective resting splint when doing lighter tasks. 12 weeks: There are no restrictions after 12 weeks. X-rays should be obtained intraoperatively, at 6 weeks, 3 months and 12 months postoperatively. This postoperative regime describes the care for a patient without complications.

25 Implants Trapezium Cup CFR-PEEK Ø6 mm S Trapezium Cup Lateralized CFR-PEEK Ø6 mm S Trapezium Cup UHMWPE Ø6 mm S Metacarpal Head Short Ø6 mm S Metacarpal Head Medium Ø6 mm S Metacarpal Head Long Ø6 mm S Metacarpal Head Extra Long Ø6 mm S Metacarpal Head Extra Extra Long Ø6 mm S Trapezium Threaded Implant length 7 mm S Trapezium Threaded Implant length 8.5 mm S Trapezium Threaded Implant length 10 mm S Metacarpal l Threaded Implant length 20 mm S Metacarpal l Threaded Implant length 24 mm S Metacarpal l Threaded Implant length 28 mm S Metacarpal l Threaded Implant length 32 mm S Metacarpal l Threaded Implant length 36 mm S Metacarpal l Threaded Implant length 32 mm XL S Metacarpal l Threaded Implant length 36 mm XL S Trapezium Salvage Cup UHMWPE 8.5 mm S 25

26 Trials Trials Metacarpal Head Short Ø6 mm Trials Metacarpal Head Medium Ø6 mm Trials Metacarpal Head Long Ø6 mm Trials Metacarpal Head Extra Long Ø6 mm Trials Metacarpal Head Extra Extra Long Ø6 mm Instruments Guide Wire Ø2 mm Impactor Ø6 mm Measurement Sleeve Cannulated drill for Metacarpal I Cannulated drill for Trapezium 7 mm Cannulated drill for Trapezium 8.5 mm Cannulated drill for Trapezium 10 mm Hex Driver 3.5 mm Trapezium Driver Tri-lobe Handle Cup and Head Forceps Cup Inserter Tray and lid

27 IFU For the latest version of this Instruction For Use. Please visit: 27

28 Swemac develops and promotes innovative solutions for fracture treatment and joint replacement. We create outstanding value for our clients and their patients by being a very competent and reliable partner. Motec Basal Thumb Joint Prosthesis Manufacturer: Swemac Innovation AB 0413 Industrigatan 11 SE Linköping Sweden Sales and distribution: Swemac Orthopaedics AB Industrigatan 11 SE Linköping Sweden Phone Fax info@swemac.com P Print date: