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DOS Kongressen 2017 ·
105
Plantar Forces Mid-Term After Hemiarthroplasty With
HemiCAP For Hallux Rigidus
Pernille Henszelman Jørsboe, Michael Stage Pedersen, Mostafa Benyahia, Mads
Holm Møller, Thomas Kallemose, Merete Brink Speedtsberg, Hanne Bloch Lau-
ridsen, Jeannette Østergaard Penny
Dept. Of Orthopaedic Surgery, Copenhagen University Hospital at Hvidovre,
Background:
Hallux rigidus can be treated with a proximal hemiarthroplasty
(HemiCAP) to preserve motion in the 1st metatarsophalangeal joint (MTPJ), but
the effect is poorly documented.
Purpose / Aim of Study:
We examined the plantar force variables (PFV) under
the hallux the 1st, 2nd, and 3rd – 5 th metatarsal heads (MH) on patients with
HemiCAP and compared to healthy controls and secondarily examined the cor-
relations of the PFVs and the 1st MTPJ range of motion (ROM) and pain.
Materials and Methods:
41 were included, median OP date 2011(2007-
2014), age 63(47-78). ROM measured by both goniometer and x-ray. Pain by
VAS 1-10. Emed (Novel) Foot Pressure Mapping System measured peak force
(N) and force/time integral (N/s). Force variables between operated feet and
controls were compared by independent two-sample t-test or Wilcoxon rank
sum test. Force variables association to ROM and pain by linear regression mod-
els.
Findings / Results:
HemiCAP/Controls: Peak force (N): Hallux: 12(1-
26)/20(4-30), 1st MH: 17(8-41)/24(14- 42), 2nd MH 24(15-37)/28(24-
37), 3rd-5th MH: 27(18-36)/30(25- 35). Force/time integral (N/s): Hallux:
1(1- 4)/4(1-12), 1st MH: 5(2- 18)/7(3-11), 2nd MH 8(4-13)/10(7- 13),
3rd-5th MH: 9(6-15)/10(8- 14), (p<0.05 for all). Dorsal ROM of the operat-
ed feet was median 45 degrees (range 10-75) by goniometer and 41 (16-70)
by x-ray. An increase in ROM reduced the PFVs under the hallux, but not under
the MHs. Most patients reported no pain and no correlation to PFVs were found.
Conclusions:
As expected increased dorsiflexion reduces the force/time inte-
gral, but a mid-term HemiCAP does not restore the joint motion to normal. De-
creased PFVs under the hallux may reflect a patient reluctance to load the first
ray although plantar forces were not linked to pain. Most report minimal pain,
but the pain score is biased by missing numbers and exclusion of revisions.
No conflicts of interest reported
57.