- See:
Midfoot/Forefoot Fractures:
- Discussion:
- involves frx at base of fifth metatarsal at metaphyseal-diaphyseal junction, which typically extends into the 4-5 intermetatarsal facet;
- Jones frx is located w/in 1.5 cm distal to tuberosity of 5th metatarsal & should not be confused w/ more common
avulsion frx of 5 th metatarsal styloid;
- this fracture is usually proximal to the metatarsal cuboid joint;
- in addition, the acute Jones frx must be distinguished from the chronic Jones frx the later of which may represent a stress frx w/ poor prognosis for healing;
- hence, strictly speaking a Jones frx is an acute injury;
- Diff Dx:
-
avulsion frx of base of 5th:
- this is the most common frx of the base of the 5th metatarsal;
-
normal apophysis:
- usually present between the ages of 9 to 14 years;
- apophyseal line runs parallel to shaft of metatarsal along its lateral-inferior margin of the tubercle;
- it does not extend proximally into the joint (unlike the fracture);
-
os peroneum:
- ossicle in
peroneus longus tendon where it is seen at the tip of the fifth metatarsal base;
- is seen in 15% of population;
-
stress frx:
- these occur distal to the ligaments which firmly bind the 4th and 5th metatarsals together;
- these may be symptomatic before radiographic evidence of frx;
- w/ stress frx (indictating a chronic frx), an atheletic pt may benefit from ORIF;
- with closed treatment the rate of non union is 50%
- if non union has developed, with widening of frx line & sclerosis, cast mobilization is unlikely to be successful;
- consider bone-grafting & internal fixation w/ compression screw;
- Clinical Presentation:
- Jones frxs may present as an acute lesion or may be seen in chronic phase, and either presentation has a prolonged healing course, compared w/ frxs of other metatarsals;
- usually, there has been gradual onset of pain on outer side of foot, & only when pain interferes w/ walking does pt seek treatment;
- if several months have passed since the onset of symptoms, established non-union may already be present.
- radiographs show non-union and medullary sclerosis or even obliteration of the medullary canal;
- Radiographs:
- in addition to fracture location (which distinguishes avulsion from Jones frx), it is important to note
characteristic features at the frx site;
- acute fractures should show sharp frx margins and no intramedullary sclerosis;
- delayed union will show persistent frx line in both cortices, periosteal callus (use hot lamp),
and intra-medullary sclerosis;
- stress frx is revealed by a widened frx line and varying degrees of meduallary sclerosis;
- frx configuration in young adolescents:
- the orientation of the apophyseal line is parallel to shaft of the metatarsal and it does not extend
proximally into the joint;
- frx lines tend to be oriented more transversely to the joint;
- Non Operative Treatment: (Acute Jones Frx)
- non operative treatment should be reserved only for acute frxs (in most cases);
- w/ a frx that is minimally displaced, is < 3 months old, and radiographs show frx w/o evidence of non-union (ie, intra-medullary sclerosis and a lucent fracture
line), non-operative treatment can be recommended;
- perhaps upto 2/3 of these fractures should heal;
-
non-wt-bearing cast for 6-8 wks is necessary for healing;
- Surgical Treatment: (Jones Frx);
- patient is position in partial lateral position on bean bag;
-
flouroscopy:
- under flourscopic guidence, a K wire is inserted for determination of proper position and length;
- the most common mistake is to direct the drill plantarly, rather than parallel w/ the shaft of the metatarsal;
- the second mistake is too position the guide wire using the oblique view;
- note that the metatarsal shaft is more narrow on the AP view, and it is possible for the pin to be centered on the oblique view where as on the
AP view the pin is eccentrically positioned;
-
incision:
- longitudinal incision is made over distal metatarsal;
- take care to avoid branches of the sural nerve which can course dorsally, and laterally over the metatarsal;
- peroneus brevis is retracted inferiorly;
- the insertion of this tendon may obscure the proper drill entry site;
-
local bone graft:
- can be obtained from tuberosity and from bone bits from the drill;
-
implants:
- consider insertion of
4.5 cancellous bone screws, 4.5 mm cannulated screws (which are used in most cases) but have available 5.5 cannulated
screws and 6.5 mm cannulated screws;
- diameter should depend on width of the canal (let the screw tap help determine the best size);
- in either case, threads must cross the frx line;
- length is usually between 40-55 mm;
- consider countersinking the screw to avoid prominence of the screw head;
- in the report by IP Kelly, the authors noted that failure is more likely when smaller diameter screws are used;
- experimental Jones fractures were created in 23 pairs of human cadaver fifth metatarsals, which were fixed using either 5.0 mm or 6.5 mm screws;
- fracture stiffness and pull-out strengths were measured for either screw type and their relationships with bone mineral density and medullary canal diameter were determined;
- poor thread purchase within the medullary canal was noted with the 5.0 mm screws, while excellent purchase was noted with 6.5 mm screws;
- pull-out strength testing revealed significantly higher pullout strengths for the larger 6.5 mm screws;
- the authors conclude that larger diameter screws may be more appropriate for intramedullary screw fixation of Jones fractures;
- Outcomes:
- in the report by Larson et al 2002, 15 patients (mean age, 21.7 years) underwent cannulated screw fixation of a Jones fracture;
- there were six treatment failures: four refractures and two symptomatic nonunions;
- mean time to full activity was 6.8 weeks for the patients with failure compared with 9 weeks for patients who did not have complications;
- although all patients were asymptomatic and radiographically progressing to union before return to full activity, only one of six patients with
failures had complete radiographic union, compared with six of seven patients with no complications;
- there was a higher proportion of elite athletes (division I or professional level) among the failure group (83%) compared with those without complications (11%);
- return to full activity, especially among elite athletes, before complete radiographic union was predictive of failure;
- ref: Intramedullary Screw Fixation of Jones Fractures. Analysis of Failure American Journal of Sports Medicine 30:55-60 (2002)
Fractures and fracture-dislocations of the tarsometatarsal joint
The Jones fracture revisited.
Fractures and anatomical variations of the proximal portion of the fifth metatarsal.
The Jones' fracture in the nonathlete.
Jones fracture. Surgical versus nonsurgical treatment.
Jones' fractures and related fractures of the proximal fifth metatarsal.
Proximal diaphyseal fractures of the fifth metatarsal--treatment of the fractures and their complications in athletes.
Fractures of the fifth metatarsal. Analysis of a fracture registry.
Fractures of the base of the fifth metatarsal distal to the tuberosity: a review.
Outpatient percutaneous screw fixation of the acute Jones fracture.
Fractures of the base of the fifth metatarsal distal to the tuberosity. Classification and guidelines for non-surgical and surgical management.
Treatment of fractures of the fifth metatarsal: a prospective study.
Intramedullary screw fixation of Jones fractures. IP Kelly. Foot Ankle Int 2001 Jul;22(7):585-9
Intramedullary screw fixation of the fifth metatarsal: an anatomic study and improved technique.
Early Screw Fixation Versus Casting in the Treatment of Acute Jones Fractures.
The Association of a Varus Hindfoot and Fracture of the Fifth Metatarsal Metaphyseal-Diaphyseal Junction. The Jones Fracture
