SCIENTIFIC RESEARCH

Subject:

The influence of an osteopathic manipulation on the os carpal accessorium bone (A) relative to the mobility of the distal phalanx (B), using a force plate as a measurement tool.

Object:

The affections of the biomechanical system are one of the first and most significant causes of lameness in sport horses (Seeherman 1992b). 60% of disfunctions are situated in the anterior leg, 95 % of which are under the carpus and which influence the osteo-articular structures (Stashak, 1987; Trotter, 1996). The os navicular problem for example is responsible for 35 % of chronical lameness in the front leg (Colles, 1983; Turner, 1990).
With this scientific work I have set out to prove the functional importance of the os carpal accessorium bone (A) in relation to the mobility of the distal phalanx (hoof), in order to obtain a better distribution of the vertical forces in the hoof (B).
In literature the importance of equilibrium in the distal phalanx (Hoof Balance) is accepted but no documentation on the interrelation between the os carpal accessorium bone and the distal phalanx can be found. In practise, orthopedic shoeing is used to improve equilibrium in the front foot, usually without reference to the structures above.

Materials and methods:

Eleven horses with an osteopathic dysfunction of the os carpal accessorium bone were the subject of this experiment. The horses were divided at random into three groups: a control group, a first test group and a second test group. In the first test group the vertical pressure was measured before and after manipulation of the os carpal accessorium bone. For the second testgroup new measurements were taken two weeks after manipulation. The horses' hoofs were positioned on the force plate, and static prints from the left and right hoofs were taken. All horses were trimmed one week prior to the experiment.
A pressure distribution plate (RSscan) covered with a 5 mm thick rubber mat was used.

Results:

The experiment took place in accordance with a standardized scheme. During each recording we looked at:

• Centre of force (C.O.F): the resultant of the vertical forces influencing the sole of the hoof

• Lateral integral force (L.I.F): the total of forces influencing the lateral part of
  the sole
  

• Medial integral force (M.I.F): the total of forces influencing the medial part of
  the sole
  

• Relation L.I.F / M.I.F: the latero-medial or medio-lateral movement of
  the forces influencing the sole
  

As regards the C.O.F 10 cases out of 18 valid prints experienced an improved central position following manipulation. 7 cases, four of which already had a good central position, didn't change at all and in only 1 case we got a worse result of the C.O.F.
Concerning the L.I.F and the M.I.F there were 13 cases which experienced either a very important latero-medial or medio-lateral shift in forces (fig. 1,2,3). This results in a better distribution of the vertical forces in the distal phalanx (hoef), which means better hoof balance.
There were 5 prints indicating a higher L.I.F and M.I.F after manipulation. Although at first sight this result didn't seem to indicate any improvement, in fact 3 of the 5 cases had significant improvement in both antero-posterior or postero-anterior movement and a better distribution of the charges.

Conclusion:

In the second test group (two weeks after the first measurement) we could see that out of 7 valid prints 4 cases returned to the situation of the first print (before manipulation). 1 case became worse and 2 cases remained unchanged.
Our conclusion is that the osteopathic manipulation of the os carpus accessorium has a positive influence on the mobility of the distale phalanx, but if we want a permanent result an ostepathic treatment is necessary because in practise we can see that many dysfunctions are influencing the os carpal accessorium bone.