.
We hope you will enjoy using the Tension ISOMETER® and that it will assist you with your procedure. The User's Guide which follows is intended to aid you in your use of the Tension ISOMETER®. The User's Guide, written in consultation with Dale M. Daniel, M.D., of the Departments of Orthopedic Surgery Kaiser Hospital, San Diego, and the University of California, San Diego, describes the instrument and presents an example of an ACL procedure.
You, as a leader among orthopedic surgeons, are in a position to make helpful suggestions regarding the instrument and this manual. We therefore encourage your commentary. Please address all correspondence to:
.
Dick Watkins
President
A: Suture Hook
B: Linear Scale
C: Sled
D: Thumb Wheel
E: Force Scale
F: Thumb Screw
The Tension ISOMETER® (TI) is used to assist in locating the path for isometric graft placement and to provide improved precision in obtaining tension and displacement measurements prior to graft fixation. The TI should be skeletally mounted with a nose extension. All measurements made with the TI are made relative to a fixed skeletal reference.
Suture Nose
The suture nose is designed for insertion into a hole made by 3/32" guide wire (K wire). A suture may be passed through the suture nose by means of a suture passer. A stainless cable .037" diameter can also pass through the tube of the suture nose. The suture nose is placed in the guide wire hole and the suture pulled through it and threaded into the TI nose piece. The TI is then fitted over the suture nose and the suture clamped on the suture hook by means of a hemostat. Compressive force holds the system in place while tests are conducted.
1. Cortex screw, 4.5 mm x 20 mm long
2. Suture passer
3. 3.2 mm drill guide
4. 3.2 mm drill
5. 4.5 mm tap
6. K wire (guide wire) 3/32"
7. Suture, No. 2
8. Hemostat, various
9. Cannulated drills as needed
The MEDmetric® Tension ISOMETER® is used to tension a ligament graft and measure changes in graft tension changes in distance between points of graft fixation with joint motion. To obtain the greatest precision with tension and displacement measurements the TI should be skeletally mounted either with the skeletal fixation plate or the appropriate nose extension. By locking the TI, joint laxity provided by the ligament graft can be evaluated prior to ligament fixation.
Procedure
A. To evaluate distance change between guide pin holes with joint motion.
1. With a guide pin place a hole through the femur and through the tibia.
2. Pass a number 2 suture or a .037" diameter wire cable through the
drill holes. Clamp the end of the suture protruding through the lateral
wall of the femur. Place the suture nose extension on the TI and pass the
suture protruding through the tibial hole through the nose piece extension.
Place the nose piece extension firmly in the tibial hole. With the sled
in the forward position pass the suture around the suture hook and clamp
it with a hemostat. (Figure 1)
3. With the knee in full extension turn the thumb wheel until the force
scale indicates a 6 lb load. Note the position on the linear scale. Flex
the knee to 90º. Adjust the thumb wheel until the force scale indicates
a 6 lb load. Note the position on the linear scale. A change in position
on the linear scale indicates a length change between the points of suture
fixation. Movement of the sled toward the front of the TI indicates an
increase in length with knee flexion and movement toward the back of the
sled indicates a decrease in length with knee flexion. (Figure 2)
B. To evaluate length change between femoral and tibial fixation sites with range of motion
1. . Pass the graft and secure it at the femoral end.
2. Locate the appropriate nose extension into the tibial hole or secure the skeletal fixation plate with a 4.5 mm cortical screw through one cortex distal to the planned site of graft fixation. (Figure 3)
3. Secure the tibial end of the graft with a number 2 braided suture.
Pass the suture through the TI nose and pass it around the suture hook
and clamp the suture.
4 Perform step A-3. (Figure 4)
C. To evaluate graft tension change with range of motion.
1. With the knee in full extension apply a 6 lb load and note the linear scale.
2. Flex the knee to 90º of flexion and adjust the thumb wheel to
the linear scale reading is the same as when the knee was in extension.
The force scale indicates the ligament load.
D. To tension the ligament graft and assess the resulting joint laxity.
1. Place the knee in the desired degree of flexion.
2. Apply the desired ligament load by adjusting the thumb wheel.
3. Lock the TI by tightening the thumb screw.
4. Assess joint laxity either with manual tests or an ARTHROMETER.
E. Tensioning for graft fixation.
1. After optimum graft orientation has been obtained and the desired
joint flexion angle and graft load conditions for fixation is determined
the graft is fixed while these conditions are maintained. (Figure 5)
MEDmetric® products are warranted by MEDmetric® Corporation to the original purchaser to be free from defects in materials and workmanship for a period of one (1) year from the date of purchase. MEDmetric® agrees within this warranty period to replace or repair, at MEDmetric's® option and without cost to the purchaser, any part or parts, returned to MEDmetric®, with transportation charges prepaid, which upon MEDmetric's® examination discloses to have been defective as a result of defects in materials and/or workmanship. In no event shall MEDmetric® be held liable for transportation expenses or any expense other than the cost of service, repair or replacement of defective parts in accordance with provisions of this warranty. Warranty services may be arranged by contacting:
MEDmetric® Corporation
7542 Trade Street
San Diego, California 92121-2412
Telephone: (858) 536-9122 or (800) 995-6066;
fax: (858) 536-9303; E-mail: info@medmetric.com
Misuse, abuse, neglect or unauthorized repairs or alterations shall void this warranty.
No implied warranties of any nature whatsoever expressly including warranties of merchantability and fitness for a particular use, shall exceed the duration of this express warranty. It being recognized that the one (1) year period from the date of purchase is a reasonable warranty period for inspection of the products to allow determination as to whether there are defects in material and workmanship, and that the warranty period is a reasonable period for such an implied warranty to exist.
MEDmetric® shall not be liable for incidental or consequential damages of any nature, and MEDmetric's® sole liability shall be for the repair or replacement of defective parts pursuant to this warranty.
MEDmetric® will not be liable for commitments or agreements
made by any of its employees, agents or dealers not in compliance with
this warranty. This warranty is expressly in lieu of any other warranty,
express or implied. This warranty gives specific legal rights to the purchaser
of MEDmetric's® products covered herby. Purchasers may also
have legal rights which vary from state to state.
We ask only that you provide us with the cause of your dissatisfaction in writing and that you inform us of your intention prior to return of the instrument.
Shipping charges are the responsibility of the purchaser. In the event of returned equipment, your account will be credited with the purchase price and applicable sales taxes only. You will be billed for the shipping charges.
We feel that ten (10) days of use is adequate to determine your acceptance of the instrument. Therefore, no extensions of the ten (10) day satisfaction guarantee will be made, except by express written authorization.
Dick Watkins
President
Terms. All invoices are due and payable thirty (30) days from date of shipment unless otherwise indicated.
Prices. Orders will be priced at the prices in effect at the date of the order. Prices are subject to change without notice.
Deliveries. Promises of shipments are estimated as closely as possible. Our Traffic Department cooperates fully in obtaining the best service from the transportation companies, and we always use our best efforts to ship within the time promised. However, we cannot always guarantee delivery dates. Unless otherwise agreed, all merchandise is F.O.B. our factory. Special shipping requests are subject to additional charges.
Returns. Merchandise may not be returned without our prior consent.
Warranty. All products manufactured by MEDmetric® Corporation are warranted exclusively in accordance with our limited warranty.
Product Changes. We reserve the right to redesign, alter or modify our products without incurring any liability whatsoever to any prior buyer of our products.
Product Specifications. All products supplied by us are designed to perform in accordance with specifications that are available from us and should be consulted prior to use. If you are in doubt, please consult our Engineering Department.
Attorney's Fees and Costs. If any acknowledgments at law or inequity is necessary to enforce or interpret the Terms of Purchase and Sale contract which becomes mutually binding upon our acceptance of your order, subject to the terms and conditions of sale herein, the prevailing party shall be entitled to reasonable attorney's fees, costs and necessary disbursements in addition to any other relieve to which he may be entitled.