Review Question - QID 218561

Torg classification zone 2 fifth metatarsal base fractures, commonly referred to as “Jones” fractures, incur a high risk for the development of nonunion. Open reduction internal fixation has been shown in various studies to improve union rates, decrease time to union, and shorten time to return to work when compared to nonoperative casting treatment.

Jones fractures have a high rate of nonunion due to the watershed vascular territory located at the base of the fifth metatarsal adjacent to the 4/5 intermetatarsal joint. The blood supply within this osseous region is provided by terminal capillaries of the metaphyseal vessels and the diaphyseal nutrient artery. Nonoperative treatment typically includes placement of a short leg cast, refraining from weight bearing for 6-8 weeks, and serial radiographic examinations to assess for fracture union. Operative management involving open reduction internal fixation has become an increasingly attractive treatment option, as various studies have shown higher union rates, decreased time to union, and shorter return to work compared to nonoperative casting. However, it is imperative to discuss all treatment options with each patient so that they may make an informed decision on the best treatment modality for their individual case.

Yates and colleagues performed a systematic review assessing the outcomes of surgical versus conservative management in the treatment of Jones fractures. They report that nonoperative treatment had a significantly higher odds ratio of fracture nonunion at 5.74 (p<0.001; 95% confidence interval 2.65-12.40). They also reported that nonoperative cohorts displayed a prolonged healing time and longer time to return to sports. They conclude by recommending operative treatment for all Jones fractures due to lesser nonunion rates and improved time to union.

Dean and colleagues performed a systematic review with a comprehensive discussion on the management of Jones fractures. The report that while operative management was superior in rates of union and faster return to work, they acknowledge a relatively high (~20%) complication rate with operative management to include nonunion or refracture. They conclude by recommending larger, multi-center trials to definitively delineate the most appropriate treatment option for Jones fractures.

Orr and colleagues performed a biomechanical analysis comparing different screw options for the treatment of Jones fractures. They report that conventional (solid, non-cannulated) partially threaded screws provided improved fracture site compression and decreased fracture site angulation compared to tapered variable pitch screws. They conclude that conventional partially threaded screws provide optimal biomechanical stability in the treatment of Jones fractures.

Bucknam and colleagues reported on the outcomes of 32 Jones fractures in the military population who underwent primary intramedullary screw fixation. At a mean follow-up time of 24 months, all patients went onto radiographic union with a 100% patient satisfaction rate. The authors concluded primary intramedullary screw fixation was a safe, reliable option for all appropriate operative candidates with Jones fractures and may result in similar early weight-bearing, osseous healing, and expeditious return to full activities consistently reported in high-level athletes.

Figure A shows an oblique fracture at the base of the fifth metatarsal with extension into the 4/5 intermetatarsal joint, consistent with a Torg zone 2 “Jones” fracture.

Answer 1: Patients can be made weight-bearing as tolerated in a hard-sole shoe, boot, or walking cast for zone 1 fractures. However, zone 2 (Jones subtype) fractures should be made non-weight bearing if placed in a non-walking cast. Regular follow-up with an orthopaedic provider is imperative to monitor for the development of a nonunion.
Answer 2: While casting results in a higher rate of nonunion compared to open reduction internal fixation, it is still considered an appropriate treatment modality for patients seeking to avoid surgery.
Answer 3: Open reduction internal fixation with an intramedullary screw has been shown to have high union rates and a quicker return to work. Patients should be educated on this in order for them to provide an informed decision on the best care for them and their circumstances.
Answer 4: Open reduction internal fixation does not have a high rate of hardware failure. The Yates study reported an 8.5% risk of re-operation in patients treated with open reduction internal fixation due to re-fracture, persistent nonunion, or symptomatic hardware.