INTRODUCTION

^{Hallux valgus is the most common forefoot deformity, with an estimated prevalence of 23% to 35% of population. Choosing the appropriate surgical approach should consider factors such as degree of the deformity and patient clinical symptoms. Lapidus is the preferred procedure for treatment of symptomatic patients with
moderate-to-severe deformity. Intercuneiform instability plays an important prognostic role in intraoperative rate of the Lapidus fixation construct and a potential cause of recurrence. Fleming at el demonstrated that the rate of Intercuneiform instability was 74% in patients treated with Lapidus Arthrodesis. It is believed that
stabilization of the Intercuneiform joints as part of Lapidus fusion arthrodesis could be beneficial in controlling the excess motion remaining and conferring additional stability not inherent in this area.1-4}

Figure 1:Pre-Op X-Rays. AP [A], Lateral [B] & Sesamoid Axial views [C].

• First TMT joint fixation using Lapiplasty 4 holes plates (Treace Medical Concepts Inc.)
• Intercuneiform fixation using a OSSIOfiber^® 4.0x26mm canulated Compression Screws

1. Dissection / Access: Dissection was performed through the same dorsal medial incision which was utilized for the 1st TMT joint fusion.
   • Incision carried down through skin and subcutaneous tissue at the 1st TMT joint.
   • The Extensor Hallucis Longus (EHL) tendon identified with the neurovascular bundle and retracted laterally.
   • A longitudinal capsulotomy was performed at the 1st TMT joint, exposing the joint surface.
   • Joint fusion performed using Lapiplasty 4-hole plates.
2. Intercuneiform stabilization:
   • Fixation Site Preparation:
   The medial to middle Intercuneiform joint was stressed by the surgeon, confirming Intercuneiform instability on intra operative fluoroscopy.
3. Tunnel preparation:
   • A K-wire provided in the OSSIO^®Compression Screw instrument pack, for 4.0mm screws, was placed from the medial cuneiform to the second cuneiform and position confirmed on fluoroscopy. The dedicated drill bit for the OSSIOfiber® 4.0 CS was then used to create the pilot hole. Pilot hole was then tapped and countersunk.
4. Implant insertion:
   • An OSSIOfiber^® 4.0x26mm Compression Screw was placed using appropriate technique from the medial cuneiform to the middle cuneiform.
   • Following screw insertion, the joint was stressed again to confirm no widening is noted.
5. Closure:
   • Subcutaneous 2.0 Vicryl sutures, followed by 4.0 Vicryl Intracuticular and 4.0 Prolene skin sutures.
   

Figure 4:Preparation for OSSIOfibe^r® 4.0 CS insertion, all steps performed over the guide wire - Drilling [A]; Tapping [B]; and Countersinking [C].

Figure 5: Inserting the OSSIOfiber^® 4.0 CS over the guide wire [A]; Screw head fully seated and flush with the bone [B].

• Week 1: Incision healing nicely with moderate post-op erythema. Patient non-weight bearing.
• Week 2: Incision has healed nicely after removal of sutures. Mild post op erythema and edema expected at this stage of healing. Right great toe is significantly more rectus. Patient can transition to weight bearing in cam boot.
• Week 4-10: Incision has healed nicely. Local erythema resolved. Right great toe is significantly more rectus. X-Rays demonstrate reduction of the bunion deformity with a healing 1st TMT joint and no Intercuneiform instability. Patient transitioned to weight bearing in a good supportive tennis shoe and slowly returned to daily activities.
• 4 months: Right great toe is significantly more rectus. X-rays, provided below (Figure 7), show reduction of the bunion deformity with fused TMT joint and no Intercuneiform instability. Patient has returned to all daily activities in her normal shoe wear and is very pleased with the final results.

Figure 7:Figure 7: 4-months post-op weight bearing X-rays, AP view, demonstrating excellent reduction of the bunion deformity with no widening of the Intercuneiform joint.

References
1. The treatment of hallux valgus. Wülker N, Mittag F. Dtsch Arztebl Int. 2012 Dec;109(49):857-67; quiz 868. doi: 10.3238/arztebl.2012.0857.
2. Intraoperative evaluation of medial Intercuneiform instability after Lapidus arthrodesis: Intercuneiform hook test. Fleming JJ, Kwaadu KY, Brinkley JC, Ozuzu Y. J Foot Ankle Surg. 2015;54:464–472.
3. Enhanced Lapidus arthrodesis: crossed screw technique with middle cuneiform fixation further reduces sagittal mobility. Galli MM, McAlister JE, Berlet GC, Hyer CF. J Foot Ankle Surg. 2015;54:437–440
4. Recurrence of Hallux Valgus After Modified Lapidus Procedure With Successful Fusion of the Intermetatarsal and Intercuneiform Joints. Long J, Lauf JA, Whitehead B, Cheney N, Law TD.. Cureus. 2021 Jun 3;13(6):e15418. doi: 10.7759/cureus.15418. PMID: 34249565; PMCID: PMC8254418.

Medical professionals must use their professional judgment for patient selection and appropriate technique.

Results from case studies are not predictive of results in other cases. Results may vary.

Please refer to the product instructions for use for warnings, precautions, indications, contraindications and technique.

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