Endolog Implant for Correction of Hallux Valgus

Transcription

1 Endolog Implant for Correction of Hallux Valgus Surgical Technique Distributed by: Simple and precise Mini-invasive For mild, moderate and severe HV

2 Surgical Indications Endolog implant is proposed for the mini-invasive surgical treatment of hallux valgus deformity correction of the follow entities: Mild IMA <11º MTF <20º Moderate IMA >11º <16º MTF >20º <40º Severe IMA >16º <18º MTF >40º Revision of previous surgery Description of Endolog The implant is composed of a curved component produced in three different sizes and an angle-stable screw in three different lengths. The main feature of the system is the curvilinear component which when introduced into the intramedullary canal, after the metatarsal osteotomy, achieves apposition to three distinct points: on the lateral cortex, with regard to the apex of the curvature, near the proximal metaphysis, with regard to the most proximal part of the implant, and the lateral surface of metatarsal head, at the distal plate-shaped part of the implant. The angle-stable screw, introduced in the metatarsal head through the hole of the plate is the final element, locking in stability of the implant. Curved Intramedullary implant dimensions: Size 44 for metatarsal canal diameter 7mm max length 28mm Size 45 for metatarsal canal diameter 9mm max length 32mm Size 46 for metatarsal canal diameter 8mm max length 32mm The angle-stable screw Ø 3.66mm, lengths: 15mm, 20mm Features of Endolog Due to the characteristics previously listed, the unique feature of Endolog is the elastic stabilisation achieved between the resected metatarsal head and the 1st metatarsal. This leads to callus formation where there is correction bone loss, allowing early mobilisation of the MTP joint. Clinical Aspects The implant provides a stable but not rigid distal osteotomy with significant improvements in all clinical parameters assessed in the pre-operative. The implant also ensures a rapid normalisation, post-operatively with: no pain good alignment disappearance of the areas of plantar hyperkeratosis no joint stiffness Advantages Simple surgical technique Low learning curve Shorter surgical time Immediate mobilisation in a flat shoe, until suture removal After suture removal, walking in large comfortable shoes Complications Minimal (Oedema - no avascular necrosis)

3 Pre-Operative Planning The pre-operative planning should be assessed on radiographs in the upright position and assessing the following parameters: Inter-metatarsal angle (IMA) Metatarsal Phalangeal angle (MTF) Proximal articular surface angle (PASA) One very important step concerns the exostosectomy, which must be performed minimally as this is going to affect the degree of correction of the inter-metatarsal angle. Exostosectomy must be made by taking distal-proximal wedge shape with a sagittal saw, in order to allow the implant to correct any valgus of the distal phalanx, thereby avoiding an additional surgical procedure. This wedge-shaped exostosectomy allows the correction of the PASA (Fig. 1). Wedge-shaped exostosectomy, distal to proximal If during the exostosectomy, it is necessary to rotate the metatarsal head clockwise or counter clockwise, then the sagittal saw blade is angled appropriately oblique on the dorsal-plantar direction (fig. 2). Oblique shape exostosectomy, dorsal-plantar view

4 Surgical Technique A dorsal-medial, longitudinal incision of 4cm is made corresponding to the exostosis of the 1st Metatarsal The neuro-vascular bundle is isolated and protected. A longitudinal incision is made to the MTP joint capsule. Disto-proximal exostosectomy made by taking a wedge shape from 2-4 mm to 0 mm. The purpose of this important step allows you to restore the valgus of the proximal phalanx in addition PASA once the flat, medial surface of the metatarsal head is resting on the flat part of the implant. (see PRE-OPERATIVE PLANNING ). A linear transverse osteotomy (by sagittal saw) is performed at the level of the distal column of the first metatarsal according to pre-operative planning. An oblique osteotomy can be used to lengthen or shorten the metatarsal. The size 46 trial implant is fitted to the impactor and locked into position using the screw-in drill guide. If the size 46 trial does not provide good stability in the medullary canal then the size 45 should be used. If the metatarsal canal is shorter in length than 30mm then the size 44 should be used. Insertion is aided by light use of a small mallet. Once the optimal trial size has been determined, remove the trial and attach the corresponding implant to the impactor, again using the screw-in drill guide. Care should be taken when inserting the implant to ensure it is without rotation and perpendicular to the longitudinal axis of the metatarsal. During insertion of the implant, translation of the metatarsal head will occur with respect to the metatarsal. Continue with the insertion of the implant until the longitudinal axis of the drill guide is aligned with the centre of the metatarsal head. Check the metatarsal head is in the correct position with fluoroscopy.

5 Note With the implant in the correct position, manually adjust: the plantar position of the metatarsal head ensure the flat, medial surface of the metatarsal head is supported by the flat part of the implant. Never adjust the implant to fit against the metatarsal head. Once these two manual adjustments have been made the metatarsal head can be temporarily stabilised with one or two 1.0mm k-wires, inserted through the micro holes located on the implant, near the drill guide. The pilot hole for the angle-stable screw can now be prepared by drilling through the screw-in drill guide. A screw length of either 15mm or 20mm can be used as indicated when either marking is flush with the proximal drill guide. Disassemble the impactor from the implant by unscrewing the drill guide and insert the angle-stable screw. Care should be taken not to de-stabilise the metatarsal head. The temporary k-wires can now be removed. Before closing, smooth the resected angle of the metatarsal to prevent soft-tissue irritation. Close and if necessary apply tension to the capsule.

6 Post-Operative Post-operative shoe with heel support for off-loading of the forefoot. Begin with delicate movements of flexion/extension of the MTP joint, gradually increasing the rehabilitation. First x-ray at 60 days. After bone consolidation is complete the implant can be removed using the dedicated impactor and drill guide. Implants Endolog implant size 44 sterile Endolog implant size 45 sterile Endolog implant size 46 sterile Endolog screw 15mm sterile Endolog screw 20mm sterile Instruments Endolog Impactor Endolog Drill Guide Endolog Screwdriver NS Graduated Drill Endolog Sterilisation Tray P Endolog trial size P Endolog trial size P Endolog trial size 46 Material Titanium TA6V ELI - ASTMF ISO Sterility is guaranteed only if the package is undamaged. Do not re-sterilise. SINGLE USE ONLY. Manufacturer: Medical Due S.r.l. Via Trento, 43 IT Castelnuovo del Garda (VR) Italy Tel. +39 (0) Fax +39 (0) P.IVA IT Reg.Imp. VR R.E.A Cap. soc. Euro ,00 i.v. UK Distributor: Osteotec Ltd, 9 Silver Business Park, Airfield Way, Christchurch BH23 3TA Tel: