Metatarsal Fractures
Indications for Surgery
1. Displacement > 4 mm
2. Angulation > 10o
3. Intra-articular
Base of 5th Metatarsal
Classification
Zone 1
- avulsion fractures
Zone 2
- fracture at the metaphyseal-diaphyseal junction
- fracture closely akin to the injury described by Jones
Zone 3
- proximal diaphysis
- stress fracture of the proximal 1.5 cm of the shaft of the fifth metatarsal
- these fractures are not acute
- always have prodromal symptoms or radiographic signs of repetitive stress injury
Zone 1
Definition
- tuberosity avulsion fracture
- usually extra-articular but may extend into cuboid-metatarsal joint
Aetiology
- Peroneus brevis contracture following inversion
DDx
1. Apophysis
- smooth and longitudinal
- appears F 9-11 M 11-14
- can look displaced or fragmented
- fuses 2-3 yrs after appearance
- apophysis does not enter cuboid-MT joint
2. Os peroneum
3. Os Vesalium
Non Operative Management
WBAT in moonboot
Randomised trial
- cast v soft dressings
- better outcome without cast
Operative indications
Displaced intra-articular fracture > 30% of articular surface / > 2mm step
- rare
- aim to restore integrity of the cuboid MT joint
Surgery
- open / closed reduction with pinning/screws
Zone 2
Definition
- transverse fracture of 5th MT shaft 1.5cm from base
- at diaphysis / metaphysis junction
- goes into the 4th/5th MT joint
Aetiology
- adduction to forefoot
Non Operative
Undisplaced fracture
- NWB for 6-8/52
- xray healing occurs from medial to lateral
- lags behind clinical healing by weeks to months
- lack of clinical healing after 8-10/52 NWB is not unusual
- consider continued protection / cast immobilisation / surgery at that time
Quill OCNA 1995
- 1/3 went on to re-fracture
- argument for early surgery
Operative
Indications
- displaced / athlete / non union
- 50% either do not heal primarily or refracture
Options
- IM screw / TBW / plate +/- bone graft
Zone 3
Definition
- diaphyseal stress fracture
- distal to 4/5 MT joint
- secondary to repetitive distraction force
X-ray
- cortical hypertrophy, narrowing medullary canal & periosteal reaction
- prolonged immobilization often required
- may take 20/52
CT
Management
NWB initially
Competitive athlete
- bone graft & IM screw +/- USS
- NWB 6/52
Lareau et al Foot Ankle Int 2016
- 25 NFL players with acute Jones fracture
- Jones specific screw with BMAC from iliac crest
- average RTP of 8.7 weeks
- 12% refracture requiring revision surgery
Surgical technique
- shaft of 5th MT is not straight
- entry point is high and medial to get straight shot
- may need to sequential increase cannulated drill size
- Jones specific screws 4.5, 5.5, 6.0 with low profile heads
Neck of 5th / Shaft metatarsal fractures
