EQUIPMENT
NAILS
The 12.5 mm nail is also available in 60, 70 and 80 mm lengths for arthrodesis of the knee. A shorter nail inserted retrogradely is however usually recommended for knee arthrodesis.
The 10.5 mm nail is only available with transverse screws, and in lengths of 10 to 40 cm. It is designed for fractures of the humerus and tibia, and for pantalar and elbow arthrodesis. It should never be used for fractures of the shaft of the femur.
The bulbous ended 12.5 mm nail has an enlarged upper quarter of 14.5 mm diameter with four oblique 14.6 mm holes to accomodate 6.5 mm cannulated compression screws for added stability of upper femoral fractures.
The 9.5, 8.5 and 7.5 nails with 3.5 mm screws, and the 5.5 and 6.5 mm nails with 2.7 mm screws only have transverse holes. They are designed for the radius and ulna, and for the smaller humerus.
SCREWS
The 3.5 screws are used with the 9.5, 8.5 and 7.5 mm nails. The 2.7 mm screws are used with the 5.5 and 6.5 mm nails.
REAMERS AND DRILL BITS
The newer sets have cannulated reamers of 8, 9, 10, 11, 12, 13, 14 and 15 mm diameter. These reamers are standard on the Huckstep locking hip set.
The smaller nails also use long drill bits from 4 to 10 mm in diameter, to ream out the medullary cavity.
The drill bits for the standard 4.5 mm diameter screws are 4 mm in diameter, and are 150 and 180 mm in length. There are three drill bits of each size. The 180 mm drill bits are designed for drilling, while the three 150 mm long drill bits are designed to stabilise the jigs on the bone and nail. There are also longer drill bits up to 300 mm if required.
The drill bits for the smaller screws vary from 2.7 mm for the 3.5 mm screws, to 2 mm for the 2.7 mm screws.
The drill for the 6.5 mm cannulated compression screws has a 6 mm diameter and is also cannulated.
INSERTER AND JIGS FOR 10.5 TO 12.5 MM NAILS
The older design of jigs have no sleeves. They are long and short transverse holed, and a short oblique holed. In addition there is a small ‘floating’ jig.
The newer design of jigs have sleeves for all except the floating jig. This is to enable drilling, tapping and insertion of screws to be carried out without removing the jig.
INSERTER AND JIG FOR THE 9.5 TO 5.5 MM NAILS
The two floating jigs, one for the 9.5 to 7.5 mm nails, and the other for the 6.5 and 5.5 mm nails are identical but smaller versions of the floating jigs used for the larger nails.
OTHER INSTRUMENTATION
SCREWDRIVERS
The screwdriver for the smaller 3.5 and 2.7 mm screws have both Phillips and transverse ends.
The 6.5 mm compression screws have a cannulated hexagonal spanner.
TAPS
The 6.5 mm tap is cannulated and coarse threaded for the compression screw.
OTHER INSTRUMENTS
b. Awl — This is to make the initial hole in the piriform fossa before reaming is commenced.
c. Extractor Attachment — This is designed to screw into the end of the nail at one end, and into a standard hip extractor at the other end. Most screws however do not require to be removed as they are made of inert titanium alloy with a low modulus of elasticity.
d. Spanner for Compressor — This is used to tighten the plastic compressor on the inserter. It is also used to tighten the nuts holding the nail and the jigs to the inserter.
e. Nuts for the Nail and Jigs — These are either knurled or hexagonal, and are used to hold the nail and the jig to the inserter.
POSITION OF PATIENT
In open nailing the patient should be in the half or full lateral position as shown.
A lateral incision should be used for fractures of the upper third of the femur.
An antero-lateral muscle splitting approach between vastus lateralis and rectus should be used for mid and lower third fractures, plus a separate small lateral incision over the trochanter.
For ‘closed’ nailing the patient should be in the standard lateral position on a traction table. The small lateral incision over the trochanter is used.
FEMORAL REAMING
The femur is reamed either from the piriform fossa just medial to the greater trochanter, or retrogradely from the fracture site when the fracture site is exposed. The effective reaming length of the reamers is 400 mm, (total length 440 mm).
Successive reamers from 8 to 13 mm in diameter are used for the 12.5 mm nail. These are the standard diameter to be used for most femoral fractures. If cannulated reamers are used, these can be used over a guide wire.
ATTACHMENT OF THE NAIL TO THE INSERTER
The nail of correct length is attached to the inserter. The inserter should have the plastic compressor screwed as proximally as possible before the nail is attaced.
The nail is then inserted into the femur by hand with a screwing motion. The inserter must never be hit with a mallet. If the nail cannot be inserted easily by hand, the femur is re-reamed with either the 13 mm or the 14 mm reamer.
A long jig arm is then screwed onto the inserter in the hole furthest from the nail. A drill bit is then inserted from the most distal appropriate hole in the inserter into the most distal hole in the nail. This is to ensure that the alignment of the jig and nail are correct. If necessary the nail is slightly rotated on the inserter using a short 150 mm drill bit before the retaining nut is tightened fully. The jig is then removed. At this stage it is also essential to note which holes in the jig mate with the relevant holes in the nail.
INSERTION OF THE NAIL
The nail is then inserted fully so that the compressor is absolutely flush with the top of the greater trochanter. The plastic compressor ensures that the nail is then 10 mm distal to the top of the trochanter.
REATTACHMENT OF THE JIG
The appropriate length of jig is than attached to the hole in the inserter as near as possible to the thigh. The nearest hole to the nail in the inserter, however. is the only one that can be used with the original oblique hole jig without drilling sleeves.
Any bone which results from the reaming should be squeezed through gauze (using a sterile press if available), and used as bone graft at the fracture site.
COMPRESSION OF FRACTURE NOT REQUIRED
The following method should be used when compression of the fracture is not required, and when only transverse screws are being inserted.
First ensure that the plastic compressor is flush with the top of the trochanter, and also screwed up as tightly as possible.
Only one of the long 180 mm drill bits should be attached to the drill and used for drilling the holes for the screws. The three short 150 mm drill bits supplied on the nail set should usually only be used only for locating the jigs onto the nail.
Drill hole (1), the most proximal of the holes in the nail is then drilled with the long 180 mm drill bit, and filled with a short 150 mm locating drill bit.
The fracture is then impacted by hand, with the correct rotation of the lower femur.
Drill hole 2, the drill hole below and closest to the fracture site itself, is then drilled out. It should not be at the fracture site itself. A short 150 mm locating drill bit is then inserted, and this will lock the fracture in place both to the nail and to the jig. Locating drill bits (1) and 2 are left in place until all the other holes have been drilled and filled with screws.
Drill holes 3, 4 and 5 below the fracture site, and drill holes 6, 7 and 8 above the fracture site are then drilled out with the long 180 mm drill bit.
In the case of the new jigs with sleeves, the holes are measured, tapped and filled with screws without removing the jig arm. Locating drill bits (1) and 2 are then removed, measured, tapped and filled with screws.
In the case of the older type jigs without sleeves, after all the holes 1 to 8 have been drilled, locating drill bits 1 and 2 plus the jig are carefully removed. This should be done without rotating or disimpacting the femur. Drill bits (1) and 2 are then reinserted to lock the femur to the nail again.
Drill holes 3 to 8 are then measured, tapped and filled with screws. Finally drill holes (1) and 2 are filled.If any hole in the nail is not immediately located, and the drill bit hits the side of the nail, the jig should be carefully removed, and the hole in the nail located with the screw depth measure. It will usually be slightly anterior or posterior to the hole in the outer femoral cortex. This hole is then drilled out and through the hole in the nail, and the medial femoral cortex.without the jig in place. The jig is then replaced, and the locating 150 mm drill bit inserted through jig, femur and nail. All further holes should be able to be drilled without trouble.
COMPRESSION OF FRACTURE REQUIRED
If compression of the fracture is required, when open reduction is being carried out, locating 150 mm short drill bit (1) should be inserted through the jig, and into a hole seen in the nail at the fracture site when the nail has been fully inserted.
The fracture is then reduced, and drill hole 2 drilled out, and filled with a short 150 mm locating drill bit
Drill holes 3, 4 and 5 are then drilled out, and short locating drill bit 4 used to lock the nail to the lower femoral fracture.
If the jigs with the drilling sleeves are used, drill holes 3 and 5 are then measured, tapped and filled with 4.5 mm fine threaded screws. Locating drill bits 2 and 4 are left in place until the end of the operation.
If one of the jigs without the drilling sleeve is used, drill bits 2 and 4 plus the jig are carefully removed, and locating drill bits 2 and 4 replaced without the jig in place. Drill holes 3 and 5 are then measured, tapped and filled with screws.
d drill holes 6, 7 and 8 above the fracture site are then drilled out with the long 180 mm drill bit.
In the case of the new jigs with sleeves, the holes are measured, tapped and filled with screws without removing the jig arm. Locating drill bits (1) and 2 are then removed, measured, tapped and filled with screws.
In the case of the older type jigs without sleeves, after all the holes 1 to 8 have been drilled, locating drill bits 1 and 2 plus the jig are carefully removed. This should be done without rotating or disimpacting the femur. Drill bits (1) and 2 are then reinserted to lock the femur to the nail again.
Drill bit (1) at the fracture site is then removed and the plastic compressor over the trochanter tightened with the spanner until the fracture site is firmly impacted. Care must be taken not to crush the trochanter, and also to make sure that the rotation of the fracture is correct.
The short floating jig is then slid over locating drill bits 2 and 4. Drill hole 6 above, and nearest to the fracture site, is then drilled out and filled with a locating short drill bit until the end of the operation.Drill holes 7, 8 and 9 are then drilled out through the floating jig. The floating jig is then slid off the 3 locating drill bits, and holes 7, 8 and 9 are filled with screws. Finally holes 2, 4 and 6 are measured, tapped and filled. A screw should never be inserted at the fracture site itself as it may cause a stress raiser.Bone graft from all the reamings, plus additional cancellous graft if necessary from the patient’s iliac crest, should be also be used in all established non unions.
In the case of closed percutaneous nailing with the use of sleeved jigs, the first drill hole (1) should be in the most proximal hole in the nail, above the fracture site. This will lock the jig accurately to the nail, and allow holes 2, 3, 4 and 5 below the fracture to be drilled. Short locating 2 and 4 drill bits are then inserted, and left until the end of the operation. Drill holes 3 and 5 are then measured, tapped and filled.Drill bit (1) is then removed, and the compressor over the trochanter tightened to compress the fracture with the correct rotation. Drill holes 6, 7, 8 and 9 above the fracture are then drilled, measured, tapped and filled. Finally locating drill bits 2 and 4 are filled with screws
ELONGATION OF THE FEMUR
In cases where the femur requires elongation, this is best done by open operation. Drill holes 1, 2, 3 and 4 are first drilled above the fracture site. Locating drill bits 2 and 4 are left in place until the end of the operation, while holes 1 and 3 are filled with screws.
The fracture site should be lengthened using skeletal traction or a spreader. Stripping of the periosteum above and below the fracture may be required to achieve the required length. This should not usually aim to be greater than 50 mm at a single operation. This is because of the risk of stretching the neurovascular structures. The action potentials in the common peroneal nerve must be recorded in all cases where these might be at risk. The knee should also be kept flexed during elongation to diminish the risk of neurovascular damage.
Drill bit 5, as illustrated, can be used to maintain length. Drill holes 6, 7, 8 and 9 are then drilled out. A short stabilising drill bit 8 is left in place, while holes 6, 7 and 9 are filled with screws. Finally locating drill bits 2, 4 and 8 are removed and filled with screws. The defect is then filled with cancellous bone graft.
The defect can also be filled with porous coated titanium alloy spacers. These are 10 mm in depth, and 30 mm in diameter, and are threaded over the nail. They require to be inserted at the fracture site after elongation of the femur, and before any holes for locking screws are drilled.
The nail is then carefully partially extracted to just above the fracture site. The spacers placed at the fracture are then threaded, one at a time over the nail, as it is advanced through the spacers and into the distal femur. The remainder of the operation is identical to that described above except that drill bit 5, which is used to maintain length, is not usually required.
It is essential to also use cancellous bone graft on the medial side of the spacers. This may be obtained from either the medullary cavity, or from the patient’s iliac crest. Only a small amount is usually required, and it should extend for the whole length of the spacers, and to the femur above and below the spacers. This graft not only adds strength to to elongation, but also by ingrowth into the porous coating prevents movement of the spacers. The spacers also obviate the necessity for homogenous bone graft with its dangers of HIV infection.
