The Collaborative International Dictionary of English v.0.48:

Rickety \Rick"et*y\, a.
   1. Affected with rickets.
      [1913 Webster]

   2. Feeble in the joints; imperfect; weak; shaky.
      [1913 Webster]

WordNet (r) 3.0 (2006):

rickety
    adj 1: inclined to shake as from weakness or defect; "a rickety
           table"; "a wobbly chair with shaky legs"; "the ladder
           felt a little wobbly"; "the bridge still stands though
           one of the arches is wonky" [syn: rickety, shaky,
           wobbly, wonky]
    2: affected with, suffering from, or characteristic of rickets;
       "rickety limbs and joints"; "a rachitic patient" [syn:
       rickety, rachitic]
    3: lacking bodily or muscular strength or vitality; "a feeble
       old woman"; "her body looked sapless" [syn: decrepit,
       debile, feeble, infirm, rickety, sapless, weak,
       weakly]

Moby Thesaurus II by Grady Ward, 1.0:

144 Moby Thesaurus words for "rickety":
   adrift, afloat, allergic, anemic, anile, apoplectic, arthritic,
   bagging, baggy, bandy, bandy-legged, bilious, blemished, bloated,
   bowlegged, broken-down, cancerous, chlorotic, clear, club-footed,
   colicky, consumptive, crabbed, dangling, debilitated, decrepit,
   defaced, deformed, dilapidated, disfigured, doddered, doddering,
   doddery, drooping, dropsical, dwarfed, dyspeptic, easy, edematous,
   encephalitic, epileptic, feeble, flapping, flatfooted, flimsy,
   floating, fossilized, frail, free, gerontal, gerontic, groggy,
   grotesque, hanging, ill-made, ill-proportioned, ill-shaped,
   in disrepair, infirm, knock-kneed, laryngitic, lax, leprous, loose,
   luetic, malarial, malformed, malignant, marred, measly,
   misbegotten, misproportioned, misshapen, monstrous, mossbacked,
   moth-eaten, mummylike, mutilated, nephritic, neuralgic, neuritic,
   out of shape, palsied, papery-skinned, paralytic, phthisic,
   pigeon-toed, pleuritic, pneumonic, pocky, podagric, precarious,
   pug-nosed, rachitic, ramshackle, ravaged with age, relaxed,
   rheumatic, ricketish, rocky, run to seed, rusty, scorbutic,
   scrofulous, senile, shaky, shriveled, simous, slack, sloppy,
   snub-nosed, spidery, spindly, streaming, stricken in years, stumpy,
   swaybacked, tabetic, tabid, talipedic, teetering, teetery,
   timeworn, tottering, tottery, truncated, tubercular, tuberculous,
   tumbledown, tumorigenic, tumorous, unanchored, unbound, undone,
   unfastened, unfixed, unsecure, unsteady, unstuck, untied, weak,
   withered, wizened, wobbly