Great Toe Endoprosthesis Surgical Technique Merete Medical, Inc. 99 Purchase Street Rye, N.Y. 10580 Phone: 914 967-1532 Fax: 914-967-1542 E-Mail: service@merete-medical.com www.merete-medical.com
- Description - DESCRIPTION ToeMobile is a two-piece prosthesis that replaces the metatarso-phalangeal joint by complete functional preservation of the joint and maintaining of the sesamoid complex. The prosthesis consists of an anatomically shaped and polished metatarsal implant, made of CoCrMo, which glides on a polyethylene inlay that is preassembled on a conically shaped phalangeal component made of titanium alloy Ti-6Al-4V. Metatarsal and Phalangeal implant are intended for cemented use only. Following implant sizes* are available: - Metatarsal Implant Four Sizes -1, 0, 1, 2 - Phalangeal Implant (Titanium component with PE-Inlay in three different heights) Nine Sizes 0.1, 0.2, 0.3 ; 1.1, 1.2, 1.3 ; 2.1, 2.2, 2.3 INDICATIONS FOR USE ToeMobile is a two-piece implant that is intended to be used as prosthesis for the metatarsophalangeal joint. The device is intended for cemented use only. Indications for use include: - Painful degenerative metatarso-phalangeal joint change - Hallux rigidus stage 3 and 4 - Hallux valgus and hallux rigidus - Hallux limitus with painful arthrofibrosis - Revisions- after moderate proximal phalanx resection PATIENT REQUIREMENTS Good neurovascular status Good bone stock Sufficient function of the flexors Patient Compliance to Post Operative Care CONTRAINDICATIONS Infection Inadequate skin, bone or neurovascular status Irreparable tendon system (e.g. Keller-Brandes) Patients with high physical demands or Non Compliant Patient Concerns Poor Bone Stock *Dimensions in mm are provided on page 11 Merete Medical, Inc. HDB0025-0811 Page 2 of 12
Surgical Technique Incision and Adequate Exposure for Implant Make a dorsal/medial incision and release the capsule structures around the joint completely to obtain adequate exposure for the implant. METATARSAL IMPLANT PREPARATION Preparation of the Medial Head Surface Remove the medial eminence with a saw to provide an even surface for the medially placed Cutting Guide. Prepare the metatarsal head with a ronguer for sizing the appropriate Metatarsal Implant. Implant Size Four different sizes of metatarsal implants are available. Place the Sizing Gauge medially on the metatarsal head to determine the size of the implant (figure 1). Accordingly, orientate the intended resection dorsally and plantarly. Next place the appropriately selected Metatarsal Sizing Template on the metatarsal head. Insert a 1.6 mm k-wire through the distal hole of the template horizontal to the load-bearing plane. Introduce the k-wire as parallel as possible to the joint axis (figure 2). If a shortening is intended, use the proximal wire holes in the Sizing Template. Remove the Implant Sizing Template, keep the k-wire in position. Figure 1 Figure 2 Merete Medical, Inc. HDB0025-0811 Page 3 of 12
Metatarsal Cutting Guide Mount the appropriate sized Metatarsal Cutting Guide over the k-wire, flush to the bona (figures 3 and 4). Figure 3 Figure 4 Once the Metatarsal Cutting Guide is positioned flush (you may have to cut or saw the medial eminence further to ensure a flush metatarsal surface medially) insert another 1.6 mm wire into the proximal wire hole in the cutting guide and hold it firmly with the locking screw. NOTE: Surgeon may decide to adjust the proximal articular set angle (PASA). This is completed by inserting another kwire into the distal/dorsal hole location on the guide. The shaft of the guide which extends proximally is thus closer to or further away from the MT-I shaft (angling toward it or away from it). See figures 5 and 6 below. Figure 5 Figure 6 Merete Medical, Inc. HDB0025-0811 Page 4 of 12
Metatarsal Saw Cuts It is recommended to prepare the saw cut by alternately driving the 1.6mm k-wires through each hole in the cutting guide, this will allow for clean removal of the bone with the sawblade. Use a saw blade with a thickness of 0.4mm and length of 25.5mm or longer to ensure cutting completely through the lateral side of the metatarsal. Remove the Cutting Guide and k-wires. Metatarsal head is prepared for trial and implant (Figure 7). Figure 7 Placement of the Metatarsal Trial Implant Select appropriate size Metatarsal Trial Implant. The Merete driver threads onto the trial for placement on the metatarsal head (figures 8 and 9). Figure 8 Figure 9 Merete Medical, Inc. HDB0025-0811 Page 5 of 12
PHALANGEAL IMPLANT PREPARATION Preservation of the Plantar Plate To preserve the plantar plate, distract the joint and insert a k-wire medially at least 4mm up from the plantar surface of the proximal phalangeal. This will give the surgeon a mark to preserve the plantar plate with a saw cut (figures 10 and 11). The distance of at least 4mm ensures sufficient protrusion of the smallest inlay height. approx. 4 mm Figure 10 Figure 11 Cut horizontally with the saw through the joint surface using the wire as guide. Next, starting dorsally, make a vertical cut with the saw along this wire. The plantar base segment of the proximal phalanx, which guides the insertion of the plantar plate with the short flexors, remains intact (figures 12 and 13). Figure 12 Figure 13 Merete Medical, Inc. HDB0025-0811 Page 6 of 12
Reaming the Proximal Phalanx Insert a 1.6 mm k-wire centered in the proximal phalangeal (figures 14 and 15). Figure 14 Figure 15 Note: For k-wire placement, pay attention to the mid-shaft course of the undermost third of the proximal phalanx. Use the cannulated starter reamer over the kwire. Three different phalangeal reamer sizes are available. Select the appropriate size reamer, starting with Size 0, ensuring adequate cortical bone is intact around the reamer and phalangeal bone for implant (figures 16 and 17). Figure 16 Figure 17 Merete Medical, Inc. HDB0025-0811 Page 7 of 12
Phalangeal Trial Implants After determining the implant diameter use the color coded phalangeal trials and mount a trial inlay to determine the thickness required (figures 18 and 19). For the test, distract the joint and achieve a distance of 6 mm between inlay and metatarsal trial implant. Surgeon may use a 6mm osteotome placed medially as a measurement guide. Check the congruence between the metatarsal trial and phalangeal trial, by putting the joint through a range of motion. 6 mm Figure 18 Figure 19 Metatarsal Implant Correction if needed. It is still possible to move the metatarsal implant location medial or lateral before drilling for actual metatarsal implant (figures 20 and 21) Figure 20 Figure 21 Merete Medical, Inc. HDB0025-0811 Page 8 of 12
Thread a Merete 2.0mm Drill Guide into the Metatarsal Trial. Use a Merete 2.0mm Drill Bit to predrill for the Metatarsal Implant stem (figures 22 and 23). Figure 22 Figure 23 Insertion of the Metatarsal Implant Open appropriate sterile packed Metatarsal Implant and impact into the metatarsal into predrilled 2.0mm drill hole. Thread Metatarsal Impactor onto the Driver and Impact firmly by using bone cement (figures 24 and 25). Figure 24 Figure 25 Merete Medical, Inc. HDB0025-0811 Page 9 of 12
Insertion of Phalangeal Implant Open the appropriate sterile packed Phalangeal Implant and impact into the reamed position by using bone cement in the proximal phalangeal. Thread the Phalangeal Impactor on the Driver and impact firmly into position (figures 26 and 27). Figure 26 Figure 27 Tension-free closure of the V-formed, opened joint capsule. Subsequent layered wound closure. Elastic forefoot bandage. Postoperative protected load bearing in medical-surgical post operative boot/shoe. Merete Medical, Inc. HDB0025-0811 Page 10 of 12
- Ordering Information - Ordering Information IMPLANTS Phalangeal Component with PE-Inlay Catalog # FM12000 FM12001 FM12002 FM12100 FM12101 FM12102 FM12200 FM12201 FM12202 Description Phalangeal Implant; size 0-1 (A = 12.8 mm; B = 4.0 mm; C = 12.0 mm) Phalangeal Implant; size 0-2 (A = 12.8 mm; B = 5.5 mm; C = 12.0 mm) Phalangeal Implant; size 0-3 (A = 12.8 mm; B = 7.0 mm; C = 12.0 mm) Phalangeal Implant; size 1-1 (A = 13.8 mm; B = 4.0 mm; C = 13.0 mm) Phalangeal Implant; size 1-2 (A = 13.8 mm; B = 5.5 mm; C = 13.0 mm) Phalangeal Implant; size 1-3 (A = 13.8 mm; B = 7.0 mm; C = 13.0 mm) Phalangeal Implant; size 2-1 (A = 14.8 mm; B = 4.0 mm; C = 14.0 mm) Phalangeal Implant; size 2-2 (A = 14.8 mm; B = 5.5 mm; C = 14.0 mm) Phalangeal Implant; size 2-3 (A = 14.8 mm; B = 7.0 mm; C = 14.0 mm) Metatarsal Component D E Catalog # FM20011 FM20000 FM20001 FM20002 Description Metatarsal Implant; size -1 (D = 15.3 mm; E = 11.8 mm) Metatarsal Implant; size 0 (D = 16.7 mm; E = 12.9 mm) Metatarsal Implant; size 1 (D = 18.1 mm; E = 14.0 mm) Metatarsal Implant; size 2 (D = 19.5 mm; E = 15.1 mm) Merete Medical, Inc. HDB0025-0811 Page 11 of 12
- Ordering Information - INSTRUMENTS Catalog # Description FM90002 Trial Metatarsal Impactor FM90005 Metatarsal Implant Impactor FM90006 Phalangeal Implant Impactor FM91011 Metatarsal Cutting Guide, Size -1 FM91000 Metatarsal Cutting Guide, Size 0 FM91001 Metatarsal Cutting Guide, Size 1 FM91002 Metatarsal Cutting Guide, Size 2 FM92011 Trial Metatarsal; size -1 FM92000 Trial Metatarsal; size 0 FM92001 Trial Metatarsal; size 1 FM92002 Trial Metatarsal; size 2 FM93101 Trial Phalangeal Set, Size 0 (0.1 ; 0.2 ; 0.3) FM93102 Trial Phalangeal Set, Size 1 (1.1 ; 1.2 ; 1.3) FM93103 Trial Phalangeal Set, Size 2 (2.1 ; 2.2 ; 2.3) FM94111 Reamer; starter FM94100 Reamer; size 0 FM94101 Reamer; size 1 FM94102 Reamer; size 2 FM95011 Metatarsal Sizing Template Set; size -1 FM95000 Metatarsal Sizing Template Set; size 0 FM95001 Metatarsal Sizing Template Set; size 1 FM95002 Metatarsal Sizing Template Set; size 2 IT11005 Mallet FH10003 Drill Bit, 2.0mm dia. FH10045 Drill Guide for Drill Bit, 2.0mm dia. FM90003 Screwdriver, 3.5mm hex CK56116 K-wire 1.6mm dia./length 80mm CK16015 K-wire 1.6mm dia./length 150mm distribured by: Merete Medical, Inc. 99 Purchase Street Rye, N.Y. 10580 Phone: 914 967-1532 Fax: 914 967-1542 E-Mail: service@merete-medical.com www.merete-medical.com produced by: Merete Medical, GmbH Alt-Lankwitz 102 12247 Berlin Tel.: +49 (0)30 77 99 80-0 Fax: +49 (0)30 76 68 03 61 Email: service@merete.de www.merete.de Merete Medical, Inc. HDB0025-0811 Page 12 of 12