Presentation Outline

Why did I start using quadriceps tendon-bone (QT-B) for revision ACL-reconstruction?

Back in 1986 I was confronted with a fair number of failed B-PT-B and Goretex ACL reconstructions. Most had no B-PT-B available any more, using the contralateral B-PT-B construct was on option but patients denied. BLAUTH in 1984 used the QT-B for ACL-reconstruction, STAÜBLI in 1990 and 1992 used QT-B for ACL-R, FULKERSON and LANGELAND in 1995 published on harvesting technique

Gross anatomy and cryosections

Anatomy and function of the quadriceps tendon and patellar ligament. The quadriceps tendon (QT), the patella (P) and the patellar ligament (PL) are integrated into the extensor apparatus of the human knee joint.

Cryosections

Cryosectional anatomy revealed regional differences in QT thickness, width, and length. Quadriceps tendon consists of four leaves. Anterior most layer coalesces to form prepatellar retinaculum (arciform layer of Scott Dye). Cryosections in sagittal plane have shown the quadriceps tendon inserts into anterior half of patellar base.

Histology

At the attachment sites of QT and PL significant differences exist in quantity and distribution of undecalcified fibrocartilage.

Function

The quadriceps tendon wraps around the femoral trochlea with increasing flexion/rotation angles. The quadriceps tendon undergoes tensional , compressional, and shearing forces.

The quadriceps tendon consists of multiple leaves of collagenous tissue varying in size and shape running longitudinally and obliquely to form a complex tension and bracing system coalescing at the base of the patella.

The patellar ligament originates from inferior pole of patella and inserts on tibial tuberosity.

Gross anatomy revealed the QT is longer and exhibits a larger cross sectional area (CSA) than the ipsilateral PL.

The quadriceps tendon-bone (QT-B) complex. QT inserting into proximal half of patella (cryosectional anatomy, midsagittal plane of right knee, millimetric scale). Note the broad attachment area of the QT into the anterior half of patellar base. The anterior most fibres continue distally to blend over the anterior aspect of the patella, creating an anterior tension band bracing system coalescing with the anterior most fibres of the patellar ligament. The myotendinous junction is located 85 mm proximal to the base of the patella in the extended knee position. The proximal intra-articular part of the patella rests on the supracondylar fat pad. The space between the posterior superior part of the patella and the suprapatellar recess is filled by the triangular-shaped suprapatellar fat pad which covers the inferior most part of the quadriceps tendon.

Next page (Figure 1) illustrates a schematical drawing of the cryosectional anatomy of both the quadriceps tendon bone and bone-patellar ligament-tuberosity : 1 myotendinous junction, 2 QT, 3 suprapatellar fat pad, 4 anterior most tension band fibres, 5 QT insertion, 6 articular surface of patella, 7 supracondylar fat pad, 8 suprapatellar recess, 9 articular genus muscle. F femur, P patella.

FIGURE 1

The bone-patellar ligament-tuberosity (B-PL-B) complex. Cryosectional anatomy of the PL including proximal origin at inferior pole of patella and distal insertion into tibial tuberosity (cryosectional anatomy, midsagittal plane, right knee millimetric scale). Note the significant difference in thickness of the PL with respect to the QT. Note also the structural differences of insertional anatomy of the quadriceps tendon into the base of patella with respect to configuration and geometry of origin of the patellar ligament at the inferior pole of the patella and broad-based distal insertion into the tibial tuberosity. The space beneath the PL and in front of the femoral trochlea is filled by the infrapatellar fat pad. Note also the engagement of the distal most articular surface of the patella into the proximal most part of the femoral trochlea in the extended position. 1 inferior half of patella, 2 origin of PL, 3 PL, 4 insertion of PL, 5 tibial tuberosity, 6 tibial insertion of ACL, 7 femoral trochlea, 8 infrapatellar plica, 9 infrapatellar fat pad, T tibia.

Structural tensile properties

10 mm wide central sections of QT-B and B-PL constructs from young male donors (mean age 24.9 years) were analysed. Cyclic preloading consisted of 200 cycles from 50 N to 800 N at 0.5 Hz. Ultimate failure loads, ultimate displacements, stiffness values at 200 N and at 800 N and energy to failure are listed in Tables 1, 2, 3, and 4.

Table 1

Specimen Ultimate load (N)

QT-B unconditioned (n = 7) 2173 ± 618

QT-B preconditioned (n = 7) 2353 ± 495

PL-B unconditioned (n = 7) 1953 ± 325

PL-B preconditioned (n = 7) 2376 ± 152

Table 2

Specimen Ultimate displacement (mm)

QT-B unconditioned (n = 7) 5.9 ± 1.2

QT-B preconditioned (n = 7) 5.6 ± 0.8

PL-B unconditioned (n = 7) 4.7 ± 1.2

PL-B preconditioned (n = 7) 4.4 ± 1.1

Table 3

Specimen Stiffness at Stiffness at

200 N (mm/N) 800 N (mm/N)

QT-B unconditioned (n = 7) 312.9 ± 49.6 474.9 ± 82.5

QT-B preconditioned (n = 7) 325.6 ± 70.7 569.5 ± 108.5

Student's t-test 0.6921 (NS) 0.0782 (NS)

PL-B unconditioned (n = 7) 423.4 ± 66.2 544.5 ± 113.3

PL-B preconditioned (n = 7) 621.1 ± 121.8 904.1 ± 148.1

Student's t-test 0.0042* 0.0003*

*significant difference, P<0.05

Table 4

Specimen Energy to Total Energy

failure (J) (J)

QT-B unconditioned (n = 7) 6.7 ± 3.3 9.0 ± 3.3

QT-B preconditioned (n = 7) 6.4 ± 1.5 9.7 ± 1.7

PL-B unconditioned (n = 7) 5.6 ± 1.9 9.6 ± 3.0

PL-B preconditioned (n = 7) 6.2 ± 1.8 10.8 ± 2.4

Mechanical tensile properties of QT and PL

Initial cross-section areas (A) and mechanical tensile properties are represented in Table 5. Stress-strain curves of unconditioned and preconditioned QT-B and at mid construct level) was significantly higher than the corresponding CSA of B-PL-constructs (Table 5) Stress values were significantly higher for the PL's than for the QT's (Table 5). The strain values of QT-B and B-PL were comparable. During testing no slippage of tendons or ligaments from the cryoplaning device occurred revealing that the cryoclamp and the bone fixation in a low melting alloy were suitable for uniaxial biomechanical testing (cyclic loading response and ultimate failure analyses).

Table 5 : Mechanical tensile properties of central parts of quadriceps tendon (QT) and patellar ligament (PL).

length of quadriceps tendon > length of patellar ligament* : 70-80 mm vs 40-50 mm

width of quadriceps tendon > width of patellar ligament*

QT PL

Cross-Sectional Area (mm2)

unconditioned 64.4 ± 8.4 36.8 ± 5.7 *

preconditioned 61.9 ± 9.0 34.5 ± 4.4 *

Ultimate Stress (MPa) 33.6 ± 8.1 53.4 ± 7.2 *

Strain at Failure (%) 14.7± 6.7 15.1 ± 4.4

Eelastic Moduli (MPa)

200 N unconditioned 200 ± 47 363 ± 94 *

800 N unconditioned 304 ± 70 459 ± 83 *

Cyclic Creep 2.2 ± 0.8 3.2 ± 1.4 *

* significant difference

The knee surgeon can affect the structural and mechanical properties of the autograft materials used in ACL-R.

By increasing the length of the graft construct the knee surgeon may influence the stiffness of the graft. The longer the graft construct the less initial stiffness the construct will exhibit. Type of fixation, fixation of the graft at tunnel entrances, tunnel locations, flexion angle at fixation, position of the patient and leg at surgery, amount of tension applied at fixation do affect the initial graft properties.

The knee surgeon can also affect the cross-sectional area of a construct :

7, 8, 9, 10 mm wide full thickness B-PT-B constructs.

Doubled, tripled, quadrupled pes tendons.

3/4 thickness anterior part of QT-B construct 10 mm wide, 6-7 mm thick, 70 mm long for primary ACL-R in high performing athletes, 15 mm wide 3/4 anterior QT-B construct for PCL reconstrcution.

11 to 12 mm wide QT-B for ACL-revision surgery.

Technique of harvesting quadriceps tendon - patella bone -construct based on gross anatomy

Graft construct selection

According to body height, body weight, physical demands, according to width and configuration of lateral part of intercondylar notch

Graft construct sizes

QT-B constructs quadriceps tendon-bone block length, width, thickness trapezoidal (w/l/t in mm)

QT PL-B

w l t w l t

ACL primary 9-10 ¥ 65-75 ¥ 6-7 10 ¥ 15 ¥ 6

ACL revision 10-21 ¥ 65-75 ¥ 6-7 10 ¥ 15 ¥ 6

PCL primary 15-17 ¥ 70-80 ¥ 6-7 15 ¥ 20 ¥ 6

Graft harvesting

Free draping of leg, patient supine, sterile leg support, sterilely

applied tourniquet, full flexion/extension.

Longitudinal skin incision, centered over base of patella. Incise fascia over QT including multiple aponeurotic layers in front of anterior surface of patella. Identify musculotendinous junction of quadriceps tendon with respect to vastus medialis, vastus intermedius, vastus lateralis.

Use templates, 9 to12 mm wide, oriented parallel with quadriceps tendon and centered over base of patella. According to gender and morphotype individual morphological variations of quadriceps tendon width, length and depth exist. Carry the incision through a depth of 6-7 mm according to precalculated cross sectional area of graft.

Create a horizontal cleavage plane by spreading a pair of scissors avoid entering the suprapatellar recess.

Lift off the anterior three quarters of the quadriceps tendon and continue the dissection in the selected plane proximally. Cut the quadriceps tendon proximally at the preselected graft length (7 to 7.5 cm). Avoid damaging the suprapatellar fat pad distally at the base of patella.

Demarcate the trapezoidal bone block at superior-anterior aspect of patella with a template. Predrill the edges of the trapezoidal bone block with a 2 mm drill bit to a depth of 6 to 7 mm.

Cut trapezoidal bone block with an oscillating saw and small saw blade. Undercut the patellar bone block with the small blade of oscillating saw held parallel with the anterior surface of the patella. Do not use triangular shaped chisels in order to avoid cracking or fissuring of the patella.

Preserve anterior most tension band structures in order to restore the anterior tension band bracing system in front of patella.

Fill bony defects at anterior aspect of base of patella with autologus bone harvested from bone tunnels.

Close the tension band system over packed autologous bone in defect at base of patella.

Close the defect of suprapatellar quadriceps tendon harvesting site. Control suprapatellar pouch using the arthroscope.

Donor site morbidity

During early functional rehabilitation the patients may experience difficulties in relearning a normal quadriceps innervation pattern. Electronic stimulations at cocontractions may enhance quadriceps reeducation.

As the knee approaches 70° of knee flexion patients may experience superior anterior knee pain while the quadriceps tendon engages into the femoral trochlea.

To minimize donor site morbidity the suprapatellar fat pad and the inferior most layer of the quadriceps tendon should be left intact at harvesting.

Closure of the quadriceps tendon defect and packing the patellar base bone bed with autologous bone (from tunnels) and restoration of anterior tension band structures (arciform layer etc.) are important features of the QT-B harvesting technique.

Rationale of using QT-bone construct in ACL revision surgery

1.  
2. Increase of cross-sectional area of ACL graft to compensate for secondary tunnel enlargement in failed ACL reconstruction.

1. Increase of QT-B construct length in posterior wall bone deficiencies.

1. Decreased harvesting site morbidity following ipsilateral QT-B harvesting.

1. Comparable structural properties with respect to normal ACL.

1. Possibility of eccentric bone harvesting at quadriceps tendon insertion at base of patella to correct for former graft misplacements.

Preoperative imaging

Standard AP

Tunnel view at 45°

Lateral view at 0° standing

Patella axial view at 30°

Presurgical planning based on image analysis

Center and ap limits of tibial tunnel in sagittal plane (Figure 2).

Center and ap limits of femoral tunnel in sagittal plane.

FIGURE 2

FIGURE 3

B) cavitation,

C) line shaped bone resorption.

Location of drill hole entrance.

Location and orientation with respect to anatomic landmarks.

Location and orientation of bony defects with respect to anatomic femoral and tibial attachment zones.

Bone grafting needed?

One stage, two stage procedure?

Additional procedures, osteotomies

Patella infera/baja?

Previous scars?

Presurgical planning and determination of previous tunnel placements TT = tibial tunnel, FT = femoral tunnel

Sagittal plane in extension

Center of tibial tunnel CTT

Anterior posterior limit of aTT

Tibial tunnel pTT

Sagittal plane

Center of femoral tunnel CFF

Anterior limit of femoral tunnel aFF

Posterior limit of femoral tunnel pFF

Frontal plane

Medial-lateral positions and orientation

Medial limit of TT anterior limit of FT

Center of TT posterior limit of FT

Lateral limit of TT

Cavitation bone defects

posterior wall

Interference fit screw hardware

Positioning

Presurgical planning

Impingement free graft placement in extension

Tangent constructed at Blumensaat’s line runs parallel at 3 mm inferior posterior distance to intercondylar roof and must intersect with anterior intercondylar area so that projected anterior limit of revision tibial tunnel lies posterior to the intersection. Use cannulated reamers, fill defect in front of the tibial tunnel.

Postoperative documentation of tunnel placement

The following routine standard radiographs are obtained prior to

discharge from knee unit

- tunnel ap 45°

- lateral extension view 0°

- knee ap 0°

- patella axial view at 30°

Rehabilitation

The foot is placed on a support to hold the leg in extension. An extension night splint is applied for I week, cryotherapy, elevation and intermittant passive motion are balanced with intermittant periods of rest and cold-compression. Full weight bearing is encouraged as tolerated. Extension-Flexion range at one week 0-0-90, at two weeks 5-0-110, at 6 weeks 5-0-140. Usually patients discard the crutches at two to three weeks. Hydrotherapy in the pool is advocated at day 5 with a sterile wound dressing.

BLAUTH W Die zweizügelige Ersatzplastik des vorderen Kreuzbandes aus der Quadricepssehne. Unfallheilkunde, 1984, 87: 45-51

DYE S, Patellofemoral anatomy. In: FOX JM, DELPIZZO W (eds) The patellofemoral joint. McGraw Hill, New York, 1993, pp1-12

FULKERSON JP, LANGELANG R,An alternative cruciate reconstruction graft: the central quadriceps tendon. Technical note. Arthroscopy , 1995, 11: 252-254

HOWELL SM, Roof impingement of ACL grafts: diagnosis, cause, prevention and late surgical correction. In: FEAGIN J (ed) The cruciate ligaments, 2nd edn. Churchill Livingstone, New York, , 1994, pp 637-648

STÄUBLI HU, Technik der arthroskopisch assistierten Substitution mittels autologer Quadricepssehne. In: Jakob RP, Stäubli HU (eds) Kniegelenk und Kreuzbänder. Springer, Berlin Heidelberg New York, 1990, pp 456-464

STÄUBLI HU, Arthroscopically assisted ACL reconstruction using autologous quadriceps tendon. In JAKOB RP, STÄUBLI HU (eds) The knee and the cruciate ligaments. Springer, Berlin Heidelberg New York, 1992, pp 456-464

STÄUBLI HU, RAUSCHNING W, Tibial attachment area of the anterior cruciate ligament in the extended knee position. Knee Surg Sports Traumatol Arthrosc, 1994, 2 : 138-146

STÄUBLI H.U., SCHATZMANN L., BRUNNER P., RINCON L., NOLTE L.P., Quadriceps tendon and patellar ligament : cryosectional anatomy and structural properties in young adults. Knee Surg Sports Traumatol Arthrosc, 1996,4 : 100-110

WOO SL-Y, HOLLIS JM, ADAMS DJ, LYON RM, TAKAI S, Tensile properties of the human femur - anterior cruciate ligament - tibia complex: the effects of specimen age and orientation. Am J Sports Med, 1991, 19: 217-225