High, inside starting point and intramedullary reaming are keys for Jones fracture fixation in athletes
Jones fractures are fractures of the proximal fifth metatarsal metaphyseal-diaphyseal junction that are common in young athletic populations, particularly elite athletes. The poor blood supply to the fifth metatarsal has been well documented, and Jones fractures develop along a watershed area between the intramedullary nutrient and metaphyseal arteries. Surgical fixation is indicated in cases of failed nonoperative treatment, re-fracture, nonunion or when more rapid recovery is required typically in active individuals.
Images: Anderson RB
Nonoperative management using a non-weight bearing cast often requires prolonged immobilization (6 weeks to 8 weeks) and has a reported failure rate of up to 50% with a high incidence of delayed union, nonunion and/or re-fracture. Prospective, randomized study results have shown that early surgical fixation of acute Jones fractures has faster times to union and return to sports compared with cast treatment. As a result, acute surgical intervention for Jones fractures has become the mainstay of current treatment in athletes, military personnel and any patients desiring an early return to physical activity.
IM screw fixation technique
Our preference is to use a solid-core stainless steel screw system specifically designed for Jones fractures (Carolina Jones Fracture System; Wright Medical Technology Inc., Memphis, Tenn.) that has been shown to have a significantly higher fatigue resistance compared to cannulated screws with a good track record during the past 8 years. Three screw sizes are available (4.5 mm, 5.5 mm and 6.5 mm) with lengths from 40 mm to 70 mm, all of which have the same thread pitch that use a common instrument set for insertion.
In elite athletes or revision cases, we routinely combine a solid intramedullary (IM) screw with bone marrow aspirate (BMA) mixed with demineralized bone matrix (DBM) (Mini Ignite; Wright Medical Technology Inc., Memphis, Tenn.) injected percutaneously into and around the fracture site to create a matrix for small bone fracture callus formation. Bone marrow contains hematopoietic and mesenchymal stem cells, the latter of which can differentiate into osteogenic precursor cells while the former can differentiate into platelets. It is our belief that the addition of BMA with DBM may be beneficial in treating Jones fractures due to their inherently poor blood supply and healing potential. We have anecdotally treated 29 National Football League (NFL) players during the past 7 years with acute Jones fractures using this technique with good clinical outcomes, return to play, and few complications. Athletes are typically able to return to competitive play on average from 6 weeks to 8 weeks after surgery pending sport and position played.
Preparation and setup
Before surgery, it is important to perform a thorough history and physical examination of the patient to determine the extent of symptoms and physical limitations along with patient expectations and goals after surgery. It is also critical to carefully evaluate standard preoperative radiographs (Figure 1) and analyze fracture location, orientation, amount of cortical thickening, and overall geometry of the foot and fifth metatarsal. While a cavovarus foot position may predispose patients to developing a Jones fracture, we do not routinely perform a correctional valgus-producing hindfoot osteotomy in athletes due to the increased morbidity and rehabilitation.
In the operating room, patients are positioned supine with a large wedge or bump placed under the ipsilateral hip to bring the foot into a slightly internally rotated position. The operating table can also be tilted to the contralateral side if more foot inversion is required. The foot is positioned at the end of the bed as well as at the edge of the bed on top of a stack of blankets to clear the contralateral foot when imaging and to facilitate guide wire placement. A sitting stool is used for the surgeon to get low enough to the ground relative to the foot in order to place the guide wire proximal to distal.
After standard prepping and draping, the foot is elevated on a stack of small towels and a small fluoroscopy (mini C-arm) is brought in from the contralateral side to facilitate acquisition of multiple anteroposterior (AP), oblique and lateral radiographs. The foot and ankle are exsanguinated and an ankle tourniquet is placed.
‘High and inside’ starting point
Without making an incision, the guide wire (2-mm K-wire) is inserted percutaneously through the skin approximately 2 cm proximal to the base of the fifth metatarsal (Figure 2). Radiographs are taken to confirm that the guide wire is in line with the IM canal on AP and lateral views. It is essential that a “high and inside” starting point be obtained in order to avoid later difficulty with drilling and tapping. The idea of a “high and inside” start point is to ensure that the guide wire and later drill, tap, and screw follow the true IM path of the fifth metatarsal and are not deflected off of or break through a cortex.
If the guide wire is in the incorrect position, we recommend completely removing the wire and inserting it percutaneously into another location. As much time as needed should be taken to obtain a correct starting point as the remainder of the case is determined by this initial step. An incision should not be made until the correct starting point is obtained as an improperly placed incision can artificially pull the guide wire in the wrong direction and commit the surgeon to a poor start point. Once the correct guide wire placement and trajectory are confirmed with fluoroscopy, the guide wire is inserted on power just past the fracture site. A marking pen is then used to draw a line along the guide wire to serve as a reference for correct trajectory of the drill, tap and screw later on.
Drilling and IM reaming
A 5-mm to 10-mm incision is made around the entry point of the guide wire with two-thirds of the incision distal and one-third proximal. A hemostat is used to create a soft-tissue pocket down to bone to facilitate placement of the cannulated drill soft-tissue protector down to bone. The soft-tissue protector reduces the likelihood of damage to the lateral dorsal cutaneous branch of the sural nerve while the cannulated 3.2-mm drill is placed over the guide wire and drilled just across the fracture site (Figure 3).
The guide wire and cannulated drill are then removed entirely and exchanged for a 3.2-mm solid drill placed in the same entry site and drill hole. Once confirmed to be in the same entry hole on fluoroscopy, the solid drill is used on reverse to serve as an IM reamer to remove any cortical thickenings, typically lateral and plantar, that may block or deflect tap and screw insertion. The solid drill is passed back and forth several times to until a clear, smooth IM path is created along the curvature of the fifth metatarsal. This technique also helps to correct any imperfections that were created at the entry site during initial guide wire insertion and/or cannulated drilling.
Tapping and screw insertion
The guide wire is re-inserted into the distal aspect of the fifth metatarsal along with a 4.5-mm soft-tissue protector. A 4.5-mm tap is used across the fracture site (Figure 4) to the predicted distal location of the screw. Proper tap sizing should generate enough torque to begin to rotate the entire foot as the tap is advanced. If no chatter is obtained, the 5.5-mm soft-tissue protector is used along with a 5.5-mm tap. All of the taps have the same thread pitch with only the diameter increasing so that the taps may be used in series without damaging the bone thread pitch.
If fracture distraction occurs during tapping, the tap should be reversed proximal to the fracture site and the fifth metatarsal should be axially loaded for fracture compression as the tap is slowly re-advanced under fluoroscopy. In cases of significant distraction we recommend using a small diameter screw (4.5 mm). Next, the predicted screw length is held against the skin and checked under fluoroscopy to determine what length is required to ensure that the screw threads are just beyond the fracture site. In elite athletes, we will typically use a 5.5-mm or 6.5-mm screw 45 mm to 55 mm in length due to patient size.
The screw is inserted carefully using fluoroscopy until the screw threads are just past the fracture site. If the screw is advanced too distally the screw head can become buried in bone, fracture compression can be lost, and/or a distal periprosthetic fracture can occur. A secure fit should be obtained with the low-profile screw head flush with bone to avoid cuboid impingement. The AP radiograph can be misleading in regards to screw head location as the base of the fifth metatarsal has a trochanter-like shape plantarly. Therefore, lateral views should be checked carefully for flush placement of the screw head. Skin is closed using one to two 3-0 nylon sutures and the soft-tissue around the incision is injected with 10 mL of a combination of 1% lidocaine and 0.5% bupivacaine.
In elite athletes and revision cases, at the beginning of the case, we obtain 30 mL of BMA from the ipsilateral iliac crest using a standard trocar and syringe system. BMA is harvested from the posterior aspect of the superior iliac spine to avoid damage to the lateral femoral cutaneous nerve. The BMA is spun down more than 15 minutes into 4 mL of bone marrow concentrate using a separator system (Magellan; Arteriocyte Medical Systems Inc., Hopkinton, Mass.). This concentrate is mixed with an injectable scaffold in DBM to create an osteoconductive, osteoinductive, and osteogenic matrix for callus formation (Mini Ignite; Wright Medical Technology Inc., Memphis, Tenn.).
A small cannula with sharp inner trocar is placed percutaneously into the fracture site and confirmed on fluoroscopy (Figure 5). The inner trocar is exchanged for a periosteal elevator that is used to create an extra-cortical envelope directly along bone plantarly, dorsally, and laterally. Next, the elevator is removed and the cannula is placed at the fracture site as the BMA-DBM mixture is slowly injected in and around the fracture. The cannula is redirected several times in order to avoid excess pressure buildup and the fracture site is monitored on fluoroscopy. BMA-DBM is continually injected as the cannula is removed and a finger is placed over the entry site for 2 minutes to 3 minutes to prevent backflow and to allow the mixture to coagulate. Final radiographs should demonstrate a “high and inside” screw placement along with partial fracture fill with BMA-DBM (Figure 6).
After skin closure and final radiographs, a soft dressing is applied followed by a short-leg splint. Patients are made non-weight bearing for 1 week in a splint followed by heel-weight bearing in a postoperative shoe or short CAM boot for the following week. Sutures are removed at 2 weeks and patients are transitioned to weight-bearing as tolerated in a short CAM boot.
Patients are transitioned to regular shoes as tolerated and activities are advanced base on pain from 4 weeks to 6 weeks. Sports-specific activities and competitive play are resumed on average from 6 weeks to 8 weeks after surgery.
Hunt KJ. Am J Sports Med. 2011;doi:10.1177/0363546511408868.
Metzl J. Foot Ankle Int. 2013; doi: 10.1177/1071100713483100.
Mologne TS. Am J Sports Med. 2005;doi:10.1177/0363546504272262.
Murawski CD. Am J Sports Med. 2011;doi:10.1177/0363546510393306.
Nunley JA. Foot Ankle Int. 2008;doi:10.3113/FAI.2008.1216.
For more information:
Andrew R. Hsu, MD; and Robert B. Anderson, MD, are from the OrthoCarolina Foot & Ankle Institute, Charlotte, North Carolina. They can be reached at 2001 Vail Ave., Suite 200B, Charlotte, NC 28207. Hsu can be reached at email@example.com. Anderson can be emailed at firstname.lastname@example.org.
Disclosures: Hsu has no disclosures. Anderson receives royalties from Arthrex Inc., DJ Orthopaedics and Wright Medical Technology Inc.; is a paid consultant for Amniox, Wright Medical Technology Inc. and Arthrex Inc.; and receives research support from Wright Medical Technology Inc.