Fifth metatarsal fractures: Review of the current concepts

Zone 1 “Avulsion tuberosity fractures”

These are avulsion fractures of the tuberosity caused by the forces exerted by the peroneus brevis tendon or, more commonly, the lateral band of the plantar fascia during foot inversion.

Zone 2 “Jones fractures”

These occur at the metaphysis-diaphysis junction and extend into the fourth-fifth intermetatarsal facet. They result from forced forefoot adduction while the hindfoot is in plantar flexion.

Zone 3 “Diaphyseal stress fractures”

These are proximal diaphyseal fractures located distal to the articulation between the fourth and fifth metatarsal bases. They can be caused by acute excessive loading of the region or by chronic overloading, as seen in stress fractures.

Zone 2 and Zone 3 fractures are susceptible to delayed healing and non-union. Treatment strategies for these fractures depend on the patient’s activity level and the healing progress.

Recent studies have shown low interrater reliability for the 3-zone classification due to inconsistent definitions of Jones fractures among surgeons and difficulty in distinguishing between zone 2 and zone 3 injuries.^[14,15] This inconsistency may result in heterogeneous patient populations in clinical studies. Consequently, some have recommended abandoning the Lawrence and Botte classification in favor of a 2-zone (metaphyseal/meta-diaphyseal) classification.^[14]

Zone 1 (tuberosity fractures)

Tuberosity fractures are the most common type of fracture. These avulsion-type fractures occur during forced inversion of the hindfoot with the forefoot in plantar flexion.^[9] Typically, these injuries happen when the foot inverts while running on uneven surfaces or landing awkwardly from a jump. Initially, the consensus was that the forceful contraction of the peroneus brevis tendon was the primary cause of tuberosity avulsion. However, subsequent studies indicated that the lateral band of the plantar fascia is the main contributor.^[7,9]

Zone 2 and zone 3

Athletes can sustain this injury during sudden, forceful changes in direction while the heel is off the ground. Landing in an inverted position can also increase stress on the metatarsals, potentially leading to fractures.^[16]

Stress fractures, on the other hand, are caused by repetitive overloading, which causes microfractures to occur at a rate that exceeds their repair ability. Various sports maneuvers have been analyzed to determine which ones apply the most stress on the fifth metatarsal. Acceleration maneuvers exert the highest bending moments on the fifth metatarsal, making them more likely to be associated with stress fractures along the shaft.^[17] In addition, plantar force at the lateral forefoot and lateral toes (2–5) peaks during two football movements: kicking and curved running.^[18]

Several risk factors are associated with proximal fifth metatarsal fractures due to the increased loading on the lateral column of the foot. Hindfoot varus, midfoot supination, and metatarsus adductus have been observed in patients who sustained fifth metatarsal fractures.^[19] O’Malley et al. noted an increased risk of refracture in National Basketball Association players with a higher metatarsus adductus angle.^[20] In addition, a high body mass index has been linked to an increased risk of zone 3 fractures attributed to the biomechanical and metabolic effects of excessive adipose tissue.^[21]

Zone 1 (tuberosity fracture)

Non-displaced tuberosity avulsion fractures are typically treated non-operatively with high success rates for union.^[23] These patients generally require symptomatic treatment, although various forms of support, such as walking boots, hard-sole shoes, and cast immobilization, have been used. Few studies have compared early functional conservative management with immobilization. Most results showed that functional treatments provided better functional outcomes and earlier return to work compared to short leg cast treatment, with no differences in fracture union or re-fracture rates.^[24,25]

The treatment for displaced tuberosity fractures remains controversial. Some authors recommend surgical fixation for fractures with more than 2 mm displacement or involvement of more than 30% of the cuboid-metatarsal articulation even though this is not based on scientific evidence. Comparisons between operative and non-operative treatment of displaced tuberosity fractures show no statistical difference in clinical and radiological outcomes.^[26]

The treatment for non-united tuberosity fractures that have failed conservative management depends on the patient’s demands, symptoms, and fracture size. Surgical treatment is usually not required for asymptomatic fibrous union.^[27] In symptomatic patients, surgery will depend on the size of the fragment. Small avulsion injuries that are not amenable to fixation can be treated with excision with or without reattachment of the peroneus brevis tendon.^[28] Larger fragments tend to be fixed. Several fixation methods can be used for tuberosity fractures, with the most common being IM screws, tension band wires, and ulnar hook plates [Figure 2]. Biomechanical studies indicate that cancellous screws are more stable than tension band wires,^[29] while hook plates are biomechanically superior to headless compression screws.^[30]

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Figure 2:

Radiographs showing fixation methods for tuberosity avulsion fracture. (a) Fragment excision and re-attachment of peroneus brevis tendon using bone anchor. (b) Intramedullary screw fixation. (c) Fixation with hook plate.

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A recent systematic review of the different treatment modalities of base of the fifth metatarsal bone fracture concluded that early functional therapy is recommended for zone 1 fractures, including the displaced, intra-articular, and comminuted ones.^[31]

Zone 2 (Jones fracture)

Treatment should be tailored to the patient’s needs and expectations. However, there has been an ongoing controversy among surgeons regarding the optimal treatment for zone 2 fractures. Some advocate for non-operative management due to favorable outcomes,^[6,32] while others support surgical intervention, particularly for high-demand patients.^[4,5,33,34] A major reason for these different opinions is the inconsistent use of the term “Jones fracture” to refer to both zone 2 and zone 3 fractures, with many studies grouping them together and leading to inaccurate results.

Conservative management typically involves non-weight-bearing for 6–8 weeks.^[12] However, recent studies have shown favorable outcomes with functional treatment that allows for early weight-bearing and free motion. A recent retrospective study of 834 proximal fifth metatarsal fractures showed no difference in time to union between weight-bearing as tolerated and non-weight-bearing treatment strategies for all fracture zones.^[35]

Surgical treatment is recommended for high-level athletes due to its association with a significantly earlier return to play and lower rates of non-union. A recent meta-analysis of 22 studies involving athletes with acute fractures at the intermetatarsal area or proximal diaphysis found that those who underwent surgical fixation achieved a quicker time to union with a higher union rate (97.3%, compared with 71.4% for those managed conservatively), and a shorter time to return to play than did those who underwent non-operative management (9.6 weeks vs. 13.1 weeks).^[33] Comparable findings have been reported in other studies.^[4]

Several methods of fixation have been described for zone 2 fractures, with IM screw fixation being the most common. IM screw fixation combined with aggressive rehabilitation protocols has become popular for treating Jones fractures in professional athletes. In a case series, Watson et al. treated 23 athletes with Jones fractures using IM screws, followed by aggressive rehabilitation. They found that all athletes returned to play within an average of 3.6 weeks (maximum of 6 weeks), which suggests that the return to play was not dependent on the radiological union. No cases of non-union were reported, although one athlete experienced a refracture after screw removal.^[36] Certain technical considerations must be considered when fixing these fractures to prevent complications. Properly sized screw is essential to provide adequate strength and prevent refracture and screw breakage. Some studies advised that IM screws should be at least 4.5 mm in diameter with smaller screw diameters associated with failure, delayed or non-union.^[37,38] However, overly large IM screws may cause stress shielding, further fracture, and ultimately delayed or non-union. In addition, solid screws have demonstrated greater fatigue resistance compared to cannulated screws.^[39] Headless compression screws provide more stiffness at the fracture site than conventional partially threaded screws but are challenging to remove if necessary.^[40] Proper screw length is crucial due to the curvature of the fifth metatarsal. Excessive screw length can breach the diaphyseal cortex, causing fracture distraction and gapping. Therefore, the screw length should be <66% of the length of the fifth metatarsal.^[41]

Plantar plate fixation is an alternative method for treating fifth metatarsal stress fractures. This method is thought to offer improved rotational resistance at the fracture site and functions as a tension band to counteract the tensile stress on the plantar lateral side of the fracture. Good outcomes have been reported with the use of plantar plates, particularly in athletic populations, though complications such as refractures and hardware prominence have been noted.^[42]

Other fixation methods include tension band wiring, either through the conventional or modified technique, which uses two cortical screws.^[43] The fifth metatarsal, extra-portal, rigid, innovative technique combines an IM cannulated medium-diameter screw with a high-resistance suture, such as FiberWire®, to enhance biomechanical stability. This approach may be an effective option to improve fixation strength when the use of large-diameter screws is restricted.^[44] Recently, Jones-specific implants have been introduced to provide more customized fixation for proximal fifth metatarsal fractures, but further studies are needed to demonstrate their effectiveness.^[45]

In cases of refracture or delayed/non-unions, management typically includes fracture site debridement, the use of bone grafting or bone mineral proteins, and stabilization with an IM screw.^[46] However, Grant et al. found no need to prepare the fracture site in their case series. They demonstrated that union was achieved within 3 months in all cases of non-union treated with percutaneous screw fixation without fracture site debridement.^[47] For revision of previous screw fixation, a larger diameter screw and re-reaming of the medullary canal are usually required.

Extracorporeal shock wave therapy (ESWT) has demonstrated positive outcomes in treating delayed and non-union fractures despite most studies having small sample sizes. Similarly, a recent randomized controlled study found that ESWT and surgical treatment were equally effective in reducing pain and achieving bone healing in soccer players with proximal fifth metatarsal stress fractures.^[48]

Zone 3 (proximal diaphyseal stress fracture)

These fractures are more prone to delayed union, non-union, and refracture. Treatment is similar to that for zone 2 fractures. In acute cases, conservative treatment with cast immobilization and non-weight-bearing can be considered for non-athletic individuals. However, for athletes, early surgical fixation with an IM screw is recommended to achieve a shorter union time and a quicker return to sports.^[49] A summary of the characteristics and treatment methods for each zone of injury is shown in Table 1.

Author’s experience

Treatment is tailored to the fracture configuration and patient demands. We recommend functional management for tuberosity avulsion fractures, allowing patients to weight bear as tolerated. For non-operative treatment of Zone 2 fractures, patients can weight bear in a walker boot for 6–12 weeks. If there is no evidence of clinical and radiographic union by 12 weeks, surgical fixation is recommended. In high-demand or athletic patients, surgical fixation with IM screw may be considered the first line of treatment, following a discussion of treatment options with the patient [Figure 3]. For Zone 3 fractures, we opt for percutaneous fixation without fracture site debridement. Hook plates are reserved for comminuted tuberosity fractures [Figure 4].

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Figure 3:

(a) Anteroposterior and (b) lateral radiographs of a 19-year-old professional footballer showing Jones-type fracture (white arrows). (c) Anteroposterior and (d) lateral radiographs 10 weeks later showing union following intramedullary screw fixation.

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Figure 4:

30-year-old female runner 8 weeks after injury. (a) Computed tomography scan showing comminuted tuberosity fracture. (b) Anteroposterior and (c) lateral radiographs following fixation with a hook plate.

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