Abstract
Background:
The use of quadriceps tendon autograft for anterior cruciate ligament (ACL) reconstruction (ACLR) has substantially increased in popularity. Advantages include similar clinical outcomes to other autografts and greater intra-articular tendon volume. However, injury to the quadriceps muscle during graft harvest may compromise quadriceps recovery, which reduces clinical outcomes. Females have been identified as being at higher risk of poor quadriceps recovery after all soft tissue quadriceps tendon ACLR, with 61% of females reported to be unable to achieve terminal extension 6 weeks after surgery.
Indications:
To allow for 15 to 20 mm of graft-to-bone tunnel healing, autografts 65 to 70 mm long and 10 mm wide have been recommended for adults. A 3-dimensional magnetic resonance imaging study showed that quadriceps tendon length correlates with height and that 90% of patients 5’6” or taller had a quadriceps tendon length >70 mm. However, the Centers for Disease Control and Prevention (CDC) data show that 80% of adult females and 18% of adult males are shorter than 5’6” tall. This means that, for about half of adults and the vast majority of females, the quadriceps tendon may not support the harvest of a 70 mm all-soft-tissue graft without potentially injuring muscle tissue.
Technique Description:
Quadriceps tendon length and morphology can be readily assessed by ultrasound. This video demonstrates an easy new method for measuring quadriceps tendon morphology using handheld ultrasound devices that takes <1 minute.
Results:
This information provides surgeons with knowledge and tools to customize graft harvest to avoid quadriceps muscle injury.
Discussion/Conclusion:
Avoiding the removal of the quadriceps muscle during graft harvest reduces the role that donor-site morbidity can play in compromising quadriceps recovery after ACLR.
Patient Consent Disclosure Statement:
The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.
This is a visual representation of the abstract.
Keywords
Video Transcript
I am Constance Chu, Professor of Orthopaedic Surgery at Stanford University and a past president of the Forum Sports Focus Group. In “Handheld Ultrasound for Personalized All-Soft-Tissue Quadriceps Tendon ACL Reconstruction,” my co-authors and I demonstrate a simple new technique to potentially reduce donor site morbidity from quadriceps tendon harvest by accounting for the wide variability in tendon morphology in adults.
Background
The use of the quadriceps tendon autograft for anterior cruciate ligament reconstruction (ACLR) has become increasingly popular. 1 Advantages include similar clinical outcomes to other autografts 5 and greater intra-articular tendon volume than bone patellar tendon autografts.
However, injury to the quadriceps muscle during graft harvest may compromise quadriceps recovery.3,6 There are reports suggesting that quadriceps strength recovery may be more challenging after autograft quadriceps tendon ACLR. Poor quadriceps recovery includes extension deficits that reduce clinical outcomes and increase risks for anterior knee pain and osteoarthritis.
Females have been identified as being at a higher risk of poor quadriceps recovery after all-soft-tissue quadriceps tendon ACLR. 4 Also, 61% of females were unable to achieve terminal extension at the 6-week follow-up. Females also had reduced quadriceps symmetry at the 6-month follow-up compared with males.
To allow for 15 to 20 mm of graft-to-bone tunnel healing, autografts 65 to 70 mm long and 10 mm wide have been recommended for adults. 7 Surgeons have increasingly used all-soft-tissue quadriceps tendon grafts to avoid morbidity from bone block harvest. However, loss of the bone block means harvesting more proximally within the quadriceps is needed to obtain a similar-length graft, which increases the risk of quadriceps injury.
Indications
The quadriceps tendon length varies by individual. 3-dimensional magnetic resonance imaging (MRI) evaluation showed that quadriceps tendon length correlated with height. 8 The mean tendon length was greater in males than in females. Moreover, 90% of patients 5’6” or taller had a quadriceps tendon length >70 mm.
However, data from the CDC show that 80% of adult females and 18% of adult males are shorter than 5’6” tall. 2 This means that for about half of adults and the vast majority of females, the quadriceps tendon may not support harvest of a 70-mm all-soft-tissue graft.
Preoperative ultrasound has shown that the quadriceps tendon length was <70 mm in nearly half of patients. 7 This ultrasound study also showed that the quadriceps tendon thins out by 60 mm proximal to the patella. Mean numbers are informative but do not tell the story for individual patients.
The quadriceps tendon length can be measured on sagittal MRI. However, clinical MRI rarely images the tendon beyond 50 mm in length. Width assessment on clinical MRI is also challenging. A selection of research MRIs taken specifically to image the quadriceps tendon demonstrates variable morphology, and a 70-mm graft may compromise recovery of quadriceps function in patients C and D.
Technique Description
Preoperative ultrasound can help determine length, as well as width and depth at the proposed harvest length. The tendon length for quadriceps harvest is more accurately measured with the knee at 90° of flexion than in more extended positions, where the tendon will not be as straight. Thus, it will be important to communicate with colleagues performing the ultrasound regarding the purpose of the scan, which will be ideally performed in a similar position as the graft harvest.
The quadriceps tendon is also superficial enough to visualize with handheld ultrasound probes. This examination takes <1 minute. I first localize the tendon by palpation, then place the probe longitudinally to the quadriceps tendon. Next, a mark is made on the skin at the quadriceps tendon insertion to the proximal pole of the patella. I then scan along the tendon fibers until I start to see muscle fibers. I then rotate the probe axially to find the distal rectus muscle in cross-section, as well as the most proximal point where I see about 1 cm of tendon width. I then rotate the probe back longitudinally to mark this spot.
In summary, the quadriceps tendon insertion is identified and marked with the probe in line with the quadriceps tendon. The distal rectus muscle is then localized in cross-section. To achieve the goal of an all-tendon graft, the probe in cross-section is moved distally to where approximately 1 cm of tendon width is seen. The probe is then rotated back in line with the tendon, and a second mark is placed. The distance between the 2 marks is measured with a tape measure to obtain the maximum all-tendon graft length.
Results
In practice, my preoperative plan based on handheld ultrasound measurements for this 5’2” tall female was to harvest a 55-mm graft. After verifying tendon width and length using an arthroscope, I harvested a solid 9 × 9 mm diameter graft that was 55 mm long. Intraoperative images show no muscle within the harvested graft and adequate residual tendon. The 55 mm graft length was sufficient to allow for 20 mm of tendon in the bone tunnels.
Discussion/Conclusion
Using preoperative ultrasound allows all-soft-tissue graft tendon harvest to be personalized to the patient's anatomy. Avoiding the removal of the quadriceps muscle during graft harvest reduces the role that donor-site morbidity can play in compromising quadriceps function after ACLR.
In summary, quadriceps morphology varies widely in adults. Females have a greater risk for poor quadriceps recovery after all-soft-tissue quadriceps tendon reconstruction. Donor-site morbidity from standardized 70 mm quadriceps tendon graft harvest may compromise quadriceps recovery. Also, 80% of female and 18% of males are not tall enough to predictably have 70 mm of quadriceps tendon length. A preoperative ultrasound, which can be done with the 1-minute handheld device, can assess tendon length and width to customize the quadriceps tendon harvest for individual patients.
Footnotes
One or more of the authors has declared the following potential conflict of interest or source of funding: C.R.C. receives research magnetic resonance imaging sequence support from GE Healthcare. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.
