Rheumatoid Arthritis and orthotics – Help needed!

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Hello everybody,
It is my first time . As a new graduate I feel I need help with a patient I saw in the clinic today. For many of you it is not complex, complicated etc. For me? I want to help him and reduce the chance of making him worse by my lack of experience in orthotics prescribing. I have done a few, but not for a rheumatoid patient.

63 year old patient presented today with history of pain in the mid-foot and forefoot. Pain is worse after activity, at the end of day and bed enough to interrupt sleep. No pain in the morning, no “stiffness”. The pain has been present for the last 15-18 moths. Today on VAS scale patient reports 8. Patient referred to an orthopaedic surgeon, who diagnosed Rheumatoid arthritis (have not seen the letter yet, to know the details). P/t told by the surgeon that he destined for a lifetime of steroid injection and surgery.

Non weight bearing assessment:
Foot first impression pes cavus
Visible swelling over the R/F sinus tarsi, ender to touch. B/F some deformity of the midfoot area (ostephytes???). B/F 2nd toe dorsal sublaxation (not fixed, toe can be fully plantarflexed), and splaying. B/F 3-5 early stages of clawing. Some distal migration of the fibro-fatty padding, padding itself good. Feet do not feel hot or swollen.
No tenderness or swelling over the Tibialis Posterior tendon or insertions, no swelling or tenderness over peroneal tendons and insertion.
Pulses good, no neurological deficit detectable (by me).
Muscle bulk good, symmetrical, good muscle strength.
STJ R/F reduced eversion, L/F good. Reduced movement and tender midtarsal joints B/F. 1st mtpj reduced dorsiflexion tender on palpation. Head of talus difficult to palate. Ankle joint good range of motion not symptomatic. Neutral calcaneum, natural fore-foot to rear-foot. Plantarflexed first ray B/F.

Standing assessment:
Hubsher test – increase in arch height some tibial rotation.
Supination resistance: hard.
Relaxed calcaneal stance B/F calc neutral towards everted, more so on the left.
“too many toes” both feet 2 toes visible i.e. lateral fore-foot to rear foot angle - abducted.
More concave shapes bellow the malleoli.
Ankle joint looks everted, midfoot remains with high arch, STJ axis average to high laterally deviated.
My patient read (as I did) that early orthotics intervention is indicated in the managamnet of RA foot.
I would like to ask (as many did before me), what should I consider? What device to go for? Any other comments (what have i missed in my assessment)?
Thanks Anna

 

Anna

There are many ways to approach this case.

Posterior tibial tendon dysfunction is a well recognised and common finding in RA. It is likely this is the cause of the hindfoot pain in the lateral STJ.

Similarly, depending on the severity and duration of the RA, you would expect some cartilage erosions to be occuring at many of the MTP joints, and varying degrees of subluxation.

You should consider getting weight-bearing plain films to carefully assess the degree of joint pathology, and where it is occuring.

Conservative care initially should consist of devices to address the PT failure (eg heel skives, inverted technique etc), and offload the MTP joints. I routinely add a metatarsal bar at the anterior edge of the device in RA to offload painful MT heads as much as possible. Suitable footwear is critical. Ensure the patient has a rheumatologist to implement disease modifying agents.

Your job is to delay deformity, reduce tissue stress and improve mobility and comfort with footwear and orthoses. The changes are progressive, and ultimately surgery may be needed (eg pan MT head resection, hindfoot arthrodesis). The longer this can be put off the better.

Hope this helps,

LL

 

Welcome Anna,

I'm an advocate of the tissue stress approach to othotic therapy. Your patient has pain in midfoot and forefoot and RA. What anatomical structures are causing the pain in those locations? What's the diagnosis? RA. RA does what to those painful structures.

An inconsistancy needs clarification. Hard supination resistance and laterally deviated STJ axis. Did you note peroneal muscle contracture when you attempted supination resistance? The resistance can come from pronation moment from the ground or pronation moment from the muscles.

Fat pad atrophy? This can be cause of forefoot pain.

Cheers,

Eric

 

Which will be the difference in the orthoses prescribing related with these two situations ?

It is correct to assume that in the case of peroneal muscle contracture we will need a cuboid pad ?

Thank you,
Daniel

 

The two situations were a lot of resistance to the examiners hands attempting to supinate the STJ with 1)no peroneal contraction and 2) peroneal contraction.

This test is a mildly flawed test to assess STJ axis medial to lateral position in the transverse plane. It is mildly flawed because the brain attached to the foot may activate muscles in response to your attempt to supinate the STJ. You can work around this flaw if you are observant. A foot with a laterally positioned STJ axis will tend to have a supination moment from the ground and your attempt to supinate the foot will cause the patient to increase their peroneal muscle activation in response. This may feel like a "hard" to supinate foot. A foot with a medially positioned STJ axis will tend to have a high pronation moment from the ground and this will feel like a "hard" supination resistance.

The medially deviated STJ axis foot gets a medial heel skive. The laterally positioned axis gets a lateral heel skive or a forefoot valgus wedge. A cuboid pad will shift the center of pressure latterally and increase the pronation moment from ground reaction force, so it could also be included in the treatment of the laterally positioned STJ axis. However, I feel you can get the same effect as a cuboid pad if you use an intrinsic forefoot valgus post. How do you add a lump to an orthotic and make it comfortable? I haven't used cuboid pads as they look like they would be uncomfortable to me.

Cheers,

Eric

 

The first thing most mature clients do, is keep wearing the same type of shoe for years, no consideration for the fact as the RA has become worse and changed the shape and function of their foot.

They need to buy a shoe that is wide enough at the fore foot not to cause compression and tight enough at the heel not to slip.

The fore foot compression may not be enough to cause pain or even discomfort for the first few hours, but later in the day it will catch up with them.

As you look at the clients shoes, with them on the foot, does the upper bulge out beyond the sole edge, is the 1st MPJ visible as it pushes up hard against the top of the upper or as you said “too many toes” is there palpable pressure on 4 & 5?

If this is the case send them to a store that can fit them better than they have been so far, l would go so far as to say avoid one of the major chain stores here in Oz as they cant fit every foot type they have ever seen despite their advert campaign, RA seems to be one they cant get right.

Next is the sole, you may consider a rocker sole for this client, not an "Toning" or "Gym in a shoe" type, too much instability in these product types for your client from what you have described.

Can you post up a picture weight baring from behind? they may also need a lateral flare modification on the sole

.

 

We have these three elements [lateral heel skive, forefoot valgus wedge,cuboid pad] used in the treatment of the laterally positioned STJ axis and each one will act in different phases of the gait cycle. How can we decide -based on patient assessment- which elements will be suitable for that pathology ? How can we estimate the supinatory moment generated by each element ?
Thank you !
Daniel

 

The heel skive will work when the heel is on the ground. The cuboid pad and forefoot valgus wedge will start to work as soon as that part of the foot contacts the ground. So, the wedge will work from forefoot loading to toe off (If the wedge is an extension that is under the met heads). Most of the time the STJ axis angles somewhat medially and this makes the forefoot tend to have a longer lever arm to produce pronation moments at the STJ.

Also these devices increase pronation moment, not supination moment. Unfortunately there are too many variables to accurately calculate the change in moment from ground reaction force. However, we don't care about the exact moment, we care whether or not the patient feels better. You try amount of adjustment and if that doesn't get the desired result you add or subtract as needed.

Regarding your question of "based on patient assessment- which elements will be suitable for that pathology?" All of the treatments mentioned create an increase in pronation moment from the ground. Therefore each of these treatments should be considered when there is a laterally positioned STJ axis. Also if there is peroneal tendonitis or fatigue. It should be considered in the presence of peroneal weakness with frequent inversion ankle sprains.

If your question was which one do I use. I'd use all of them while thinking about patient comfort and the patient's shoes. For example, the forefoot valgus extension will take up a significant amount of volume in the shoe. If the patient wants/needs to wear a shoe with little extra volume then you gradually have to scale back what you can do. You have got to have the shoe discussion with the patient. An intrinsic forefoot valgus post will also need a shoe with a little more volume. The best orthotic is the one that fits in their shoe and doesn't stay in the closet. I'm still trying to see how a cuboid pad is more comfortable than an orthotic made from a cast taken with the midtarsal joint dorsiflexed to resistance or to a point where the lateral boarder of the foot is straight when viewed in the sagittal plane (which ever comes first.) (In some feet the lateral column will achieve a position where the metatarsal will dorsiflex past straight.) An intrinsic forefoot valgus post will lift the whole length of the lateral column instead of just a smaller area under the cuboid (as with a cuboid pad.)


Cheers,
Eric

 

Thank you all for help. Now I need to go and think again!

Anna m.

 

You have right, the correct question it was : "How can we estimate the pronation moment generated by each element ? "
Thank you for the answer !
Daniel