Advances in the Surgical Treatment of Basal Thumb Arthritis and Instability Suture Button Suspensionplasty Using the Instratek CMC Cable FIX A Case Report Andrew K. Lee, M.D., Mark Khorsandi, D.O., Jackson Ombaba, M.D., Randolph Lopez, M.D., Baher Maximos, M.D. INTRODUCTION The treatment for painful basal thumb osteoar- thritis has been the focus of many hand surgeons due to the condition’s relatively common incidence and debilitating symptoms. Disagreement still exists today about which surgical treatment is optimal; however, trapezium excision and various types of ligamentous reconstruction (i.e., LRTI) seems to be the preferred treatment option. In the advancing field of minimally invasive surgery, many surgeons are interested in faster and less intrusive ways to obtain their desired results. This paper describes the procedure and the outcome of a patient who had undergone a trapezium excision and ligament reconstruction using the CMC Cable FIX™ (Instratek Inc.®, Houston, TX) which is a minimally invasive inter-metacarpal suture button suspensionplasty system. joint, sclerosis of the subchondral bone with osteophyte formation and mild radial subluxation of the 1st metacarpal base (Figure 1). The 1st web space angle was 24 degrees. A diagnosis of osteoarthritis, Eaton stage III, was assessed. Her persisting symptoms despite conservative management indicated that a trapeziectomy and ligament reconstruction were warranted. We discussed with the patient the option of using the CMC Cable FIX ™ for ligament reconstruction, and she agreed to proceed. PREOPERATIVE EVALUATION L.H. is a 59-year-old female who had been complaining of left thumb pain for about one year. She had difficulty opening doors, turning a key to start her car, and buttoning shirts. The physical examination revealed swelling and tenderness at the thumb CMC joint, and a positive grind test was confirmed. The patient had thumb abduction of 28 degrees and demonstrated a grip and pinch strength of 28.7 lbs. and 7.3 lbs., respectively. The preoperative DASH score* was 37.5. The radiograph demonstrated narrowing of the trapeziometacarpal Figure 1 Preoperative Radiograph OPERATIVE PROCEDURE U nder tourniquet control, we first performed a standard open trapeziectomy. The entry point for the guide wire was then assessed by palpating the base of the 2nd metacarpal (Figure 2). A 7-mm incision was then made at the dorsal ulnar base. We carried out blunt dissection with Littler scissors to identify the extensor tendon, which was retracted. The dorsal ulnar cortex of the 2nd metacarpal was then exposed. The tip of the supplied 1.3-mm k-wire was placed at the ulnar side of the proximal metaphysis and at the center of the metacarpal with respect to the sagittal plane. Pinning in the direction of the 2nd metacarpal to the 1st metacarpal was performed. (This facilitates a central drill hole placement at the 2nd metacarpal). The position of the k-wire was confirmed with the C-arm radiographs and under direct vision (Figure 3). The base of the thumb was then held in a reduced position, and the k-wire was drilled to the midpoint of the 1st metacarpal base. (Ideally, the exit point should be about 5 mm to 1 cm volar to the metacarpal ridge, where the thenar muscles begin, so that the round button can be buried underneath the thenar muscles. This would help avoid any implant tenderness). In the AP plane, the wire was aimed at the base of the thumb metacarpal approximately 5 to 10 mm distal to the joint surface. The k-wire was passed radially outside the skin about 3 cm. Good positioning of the k-wire was confirmed by fluoroscopy in both AP and lateral views. A 7-mm incision was made at the exit point on the k-wire and blunt dissection was performed to expose the radial cortex of the 1st metacarpal. Reaming was then performed utilizing the 2.7 cannulated drill bit from the 2nd metacarpal to the 1st metacarpal under fluoroscopic control (Figure 4). With the cannulated drill bit in place, the k-wire was removed and the tip of the guide wire suture assembly was inserted through the cannulated drill bit so that the tip was well ulnar to the 2nd metacarpal (Figure 5). Figure 2 Palpating the base of the 2nd metacarpal for dorsal ulnar entry point of the guidewire Figure 3 Radiograph confirmation of the k-wire position The drill bit was then retrograded ulnarly, leaving the implant assembly within the bone tunnels. The guide wire suture assembly was gently pulled through both bone tunnels, exiting ulnarly of the Figure 4 Overdrilling the k-wire leaving the drill bit in position -2- metacarpal until the 2-hole round plate was seated on the 1st metacarpal cortex. Holding the oblong plate with a hemostat and guide wire with a hand, the oblong plate was detached from the guide wire (Figure 6). The guide wire was set aside for disposal. The two strands of suture were tensioned gradually until the oblong plate was firmly attached to the 2nd metacarpal cortex. (This is best accomplished by pulling each strand independently in small increments until the oblong plate is seated firmly against the cortex of the 2nd metacarpal, deep to the extensor tendon). Good positioning of the round and oblong plates was confirmed. While the thumb was held in an abducted and reduced position, 3 surgeon’s knots were tied (Figure 7). (This technique avoids over-tightening of the cable, which can result in loss of thumb abduction and impingement of the two metacarpals). The sutures were then cut and buried. The wounds were irrigated and then closed with 5-0 nylon simple sutures. A sterile dressing and a protective thumb spica splint were then applied. The additional time required for the CMC Cable FIX™ procedure was 9 minutes. Figure 5 Inserting implant guidewire into cannulated drill bit POSTOPERATIVE EVALUATION T he patient returned to our office for the first postoperative follow-up at 10 days. We removed the sutures and started occupational therapy in order to initiate early range-of-motion and scar management. A thumb spica splint was used off-and-on for the patient’s comfort. At the 4-week follow-up, she was using the hand quite well without significant pain. The patient returned to work at 2 weeks post-op. At the 8-week follow-up, she had improved her DASH score to 20 and by 12 weeks, her grip and pinch strength normalized to 29 lbs. and 7.9 lbs., respectively. By 20 weeks, her grip and pinch strength improved to 32 lbs. and 9.8 lbs., respectively, with a DASH-score of 4. The thumb abduction improved to 44 degrees. The radiographic examination at the 20-week follow-up showed a 1st webspace angle of 36 degrees with no evidence of subsidence of the 1st metacarpal or instability (Figure 8). Her Basal Joint Arthroplasty Outcome Survey (BJAOS) score** was 16 out of 16 at 20-week follow-up. Figure 6 Detaching oblong plate from the guidewire Figure 7 Fixation of CMC Cable FIX with ulnar knot position -3- require intervention (¹). The main cause of disease is thought to be attenuation of the palmar beak ligament, which is one of the primary basal thumb stabilizers, resulting in increased metacarpal translation and shear force on the trapezium articular surface (²). Non-operative treatment is considered first; however, surgical intervention is often needed. The principal surgical intervention includes various types of arthroplasty and in some cases arthrodesis for younger active patients and those patient populations requiring a strong grip for activities (¹,³). A number of implants have been devised for thumb joint arthroplasty, including silicone and metallic implants, but they are plagued by numerous complications, including subluxation, subsidence, implant wear, and several other reported complications in the literature (4,5). Although various surgical techniques are employed based on the surgeon’s training, expertise, and preferences, none has been proved to be superior to the others (6). Figure 8 Post Operative Radiograph The traditional trapezium excision arthroplasty with ligament reconstruction, tendon interposition (LRTI), has been a seemingly standard procedure for advanced-stage osteoarthritis (7). This procedure seeks to recreate the anterior oblique ligament and the intermetacarpal ligament, which are important stabilizers of the thumb. The importance of a primary stabilizer and the weakness and instability after trapeziectomy alone have led to the recommendation of ligament reconstruction in both early- and late-stage osteoarthritis (8,9,¹0). Although the need for ligament reconstruction has been questioned (¹¹,¹²), a recent ASSH survey showed 68% of the hand surgeons still feel that ligament reconstruction is important and have included it in their protocol (¹³). Table 1. Preoperative and Postoperative Comparison Physical & Radiographic Examination Pre-Op 12-Week Follow Up 20-Week Follow Up Thumb Abduction 28 deg 35 deg 44 deg Grip Strength 28.7 lbs 29 lbs 32 lbs Pinch Strength 7.3 lbs 7.9 lbs 9.8 lbs 37.5 20 4 24 deg 30 deg 36 deg DASH Score 1st Web Space Angle CMC Cable FIX achieves the goal as the stablizing component of traditional ligamentous reconstruction. However, this minimally invasive procedure with a brief learning curve recreates the critical anatomical stabilizing component without the many complex procedures and potential long-term complications of the traditional LRTI (Table 2). DISCUSSION Basal thumb arthritis can be very debilitating, because it may cause severe pain during the activities of daily living. It is the second most common joint affected in the hand and the most common to The advantages of this system compared to traditional LRTI include that it avoids the need for an -4- Table 2. Advantages of the CMC Cable FIX Compared to LRTI CMC Cable FIX LRTI • Minimally invasive (Percutaneous) • Require multiple incisions • Less OR time (Avg. 11 min.) • Longer operative time • No need for immobilization • Postoperative immobilization • No donor site morbidity or scarring • Sacrifice a functioning tendon • No altered biomechanics of the wrist • Altered biomechanics of the wrist • Brief learning curve • Technically challenging • Possibly faster recovery • Higher complication rate CONCLUSION autograft harvest, which can alter the wrist mechanics, and that it can be performed percutaneously. The CMC Cable FIX can be combined with any type of trapezium arthroplasty, such as total or partial trapeziectomy, with or without interpositional graft, and open or arthroscopic trapeziectomies. Another advantage is the reduced operative time (9 minutes in this case) compared to LRTI, which is typically an additional 30 minutes (¹4). This minimally invasive CMC Cable FIX proce- dure may provide improved outcomes by achieving anatomical correction of basal thumb instability without the complex procedures and potential complications of traditional LRTI. This procedure can reduce operative time and morbidity, and may facilitate a quicker recovery than the traditional basal thumb ligamentous reconstruction techniques. We plan to conduct a randomized comparative study to confirm these results. This patient had the early range-of-motion protocol at 2 weeks since there was no need to immobilize the thumb for tendon or tendon-to-bone healing. The thumb abduction improved from 28 degrees to 35 degrees at 12 weeks. She regained grip and pinch strength from 27.3 lbs. to 29 lbs. and 7.3 lbs. to 7.9 lbs. at 12 weeks and further improved to 32 lbs. and 9.8 lbs at 20 weeks, respectively. Her functional capability was improved as reflected on her DASH score (from 37.5 to 20 at 12 weeks and 4 at 20 weeks). She demonstrated a relatively early return to work of 2 weeks. The patient was very pleased with the outcome shown by the maximum basal joint arthroplasty survey score. * DASH stands for Disability of the Arm, Shoulder and Hand. It is a 30-item, self-report questionnaire designed to measure physical function and symptoms. A score of 0 is normal and 100 is complete disability. ** BJAOS score is a patient satisfaction scoring system. 0 is total dissatisfaction and 16 is complete satisfaction. -5- CITATIONS 1. Carroll RE: Fascial arthroplasty for the carpometacarpal joint 1. Pellegrini VD Jr. Osteoarthritis at the base of the thumb. Orthop Clin North Am 1992; 23:83–102. 2. Pellegrini VD Jr., Olcott CW, Hollenberg G. Contact patterns in the trapeziometacarpal joint: the role of the palmar beak ligament. J Hand Surg Am 1993 Mar; 18(2):238–44. 3. Rizzo, M. Moran SL. Alexander YS. Long Term Outcome of Trapezialmetacarpal Arthrodesis in the Management of Trapezialmetacarpal Arthritis. 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Tomaino MM, Pellegrini VD Jr, Burton RI: Arthroplasty of the basal joint of the thumb. Long-term follow-up after ligament reconstruction with tendon interposition. J Bone Joint Surg 1995; 77(3):346–355. 11. Field J, Buchanan D. To suspend or not to suspend: a randomised single blind trial of simple trapeziectomy versus trapeziectomy and flexor carpi radialis suspension, J Hand Surg, 2007; 32E: 462–466. 12. Wajon A, Ada L, Edmunds I. Surgery for thumb trapeziometacarpal joint osteoarthritis. Cochrane Database Syst Rev 2005. 13. Wolf JM, Steven Delaronde S. Current trends in nonoperative and operative treatment of trapeziometacarpal osteoarthritis: a survey of US hand surgeons. J Hand Surg 2012; 37 (1):77–82. 14. Brunton et al., AAHS survey 2010; ASSH Member Survey Current Practice. Patterns in Treatment of Advanced CMC Osteoarthrosis. -6- 4141 Directors Row, Suite H Houston, TX 77092 (800) 892.8020 USA (281) 890.8068 FAX USA www.instratek.com