How come? she hurt herself? can she use the arm? if the latter is the case, then predator-style wrist-blades would be perfect for her:D
Or perhaps the 'katar' (old indian weapon, as in indian indian, not red indian), where there are a set of paired handles close together, plus a grip or guide further up, set between the outer long section behind the blade, so it can be punched forward with considerable force. Some, called 'scissors katar' the handles can be squeezed together causing a secondary pair of blades to flick out in a V shape, so as to catch other blades.
And as with anyone it isn't how many you have its what you can do with them that counts. Be it disembowelling, bowling or friendly pursuits.