What Recent Studies Reveal About Proximal Fifth Metatarsal Fractures

If you enjoy sports, this time of year is about as good as it gets. Major league baseball will soon be starting the postseason (Go Cubs!). The National Football League and college football have both started (Go Colts and Hoosiers!) Soon both the National Basketball League and college basketball will begin their training camps and preseason practices (Go Pacers and Hoosiers!). Finally, fall is considered marathon season (Go runners!). Athletes of all levels are prone to proximal fifth metatarsal fractures. Therefore, you may be seeing a few more of these types of injuries this time of year.

I just read 50 to 60 articles on proximal fifth metatarsal fractures in preparation for an upcoming lecture. (Yes, it is incredibly time-consuming to put together a new lecture, especially when you are an article nerd.) As team podiatrist for the Indiana Pacers for more 20 years, I was interested to read two articles on proximal fifth metatarsal fractures in NBA and NFL players. Both articles were published this year, providing the most up-to-date approaches for Zone 2 and 3 fractures. Lawrence and Botte describe Zone 2 fractures occurring at the metaphyseal-diaphyseal junction (Jones fracture) and Zone 3 fractures at the diaphysis (diaphyseal stress fractures).¹

O’Malley and colleagues published the largest review of Zone 2 and 3 fractures in NBA players.² The review consisted of 10 players with seven having percutaneous internal fixation with bone marrow aspirate concentrate (BMAC) and three receiving the same treatment plus open bone grafting.² All players had fixation with solid, indication-specific screws with four patients requiring 5.5 mm screws and six patients using 6.5 mm screws.² The study authors determined screw diameter (after pin fixation and drilling with a 3.2 mm drill, they used increasing tap diameters until the forefoot torqued) and length (all threads just distal to fracture while staying proximal to curve of the metatarsal) specifically for each player.² Radiographic healing occurred at an average of 7.5 weeks and return to play averaged 9.8 weeks.² Three players suffered re-fracture but the authors noted no significant difference between the two groups clinically or radiographically.² O’Malley and coworkers did note that the re-fracture group had a higher, yet not statistically significant, metatarsus adductus angle.² According to the study authors, most of the players had a pes planus foot structure and nine out of 10 patients had a prominent fifth metatarsal base.²

Lareau and collagues treated 25 NFL players with Jones fractures (72 percent Zone 2 fractures and 28 percent incomplete Zone 3 fractures) similar to O’Malley and coworkers (14 5.5 mm screws and 11 6.5 mm screws) with the additional use of a bone stimulator and aggressive patient-specific rehabilitation program.³ Three patients (12 percent) experienced a re-fracture and required revisional surgery.³ All players were able to return to play The study authors found that the average return to play in the same season was 8.7 weeks.³ Bone healing typically occurred at six weeks. At this time, the authors placed the patient in a clam shell orthosis and running shoe to protect the operated site.³ Once the players returned to play, the authors utilized custom-molded foot orthoses with a lateral hindfoot post. 

The take-home message from both of these articles for treating Zone 2 or 3 proximal fifth metatarsal base fractures is the technique and type of fixation. They made the 2 cm incision just proximal to the metatarsal base parallel to the plantar surface of the foot.^2,3 They placed a guide pin “high and inside” (dorsal and medial on AP radiograph) with subsequent drilling past the fracture with a 3.2 mm cannulated drill.^2,3 The authors proceeded with intramedullary tapping by increasing the tap size by 1 mm until the forefoot began to torque to determine screw diameter.^2,3 The screw should be an indication-specific, solid, headed, partially-threaded stainless steel screw. Screw length should be just long enough to allow all threads to extend distal to the fracture site without reaching the normal curve within the fifth metatarsal.^2,3

These articles provide excellent insight to the most up-to-date treatment for a relatively common foot fracture. Utilizing the approach employed by both studies for elite athletes provides reproducible results for treating all levels of athletes with Zone 2 or 3 proximal fifth metatarsal fractures.

References

1. Lawrence SJ, Botte MJ. Jones' fractures and related fractures of the proximal fifth metatarsal. Foot Ankle. 1993;14(6):358-365.
2. O’Malley M, DeSandis B, Allen A, et al. Operative treatment of fifth metatarsal Jones fractures (zones II and III) in the NBA. Foot Ankle Int. 2016;37(5):488-500.
3. Lareau CR, Hsu AR, Anderson RB. Return to play in National Football League players after operative Jones fracture treatment. Foot Ankle Int. 2016;37(1): 8-16.