The rectus femoris tendon is a promising graft option for knee ligament reconstruction thanks to its predictable anatomy and suitable dimensions.
The rectus femoris (RF) tendon has gained interest as an autograft source for knee ligament reconstruction, including anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) procedures.
This article summarises the key findings of the scientific study Rectus femoris tendon morphometry and practical landmarks for harvesting: A cadaveric study lead by Pr. Cavaignac and his peers.
Rectus femoris tendon anatomy
The rectus femoris tendon forms the superficial layer of the quadriceps tendon and shows a consistently reproducible structure. This predictable organisation is important because a reliable graft requires identifiable layers and safe harvesting zones.
Anatomical structure
The RF tendon originates from the iliac bone and runs along the anterior part of the quadriceps. Distally, its fibres merge into the quadriceps tendon before attaching to the patella. The study identifies two constant fusion zones:
- Distal fusion: located 22.4 ± 3.5 mm above the patella
- Proximal fusion: located 58.5 ± 13.2 mm above the patella
Between these points lies a 36.1 mm segment free of deep attachments, meaning surgeons can isolate the tendon without disturbing underlying fibres.
Dimensions relevant for grafting
The study reported the following average characteristics:
- Total tendon length: 300.8 ± 29.6 mm
- Width: increasing proximally from 20 mm (5 cm above patella) to 47 mm (20 cm above patella)
- Thickness: greatest near the patella (around 2 mm), tapering proximally
These dimensions confirm that the tendon is long and strong enough to serve as a graft for both primary and revision ligament surgeries.
Graft options using the rectus femoris tendon
The rectus femoris tendon can be configured in several ways, depending on the requirements of the ligament reconstruction.
Folding configurations
A 1-cm-wide strip harvested along the recommended oblique path can be folded into:
- Double-strand graft: 8.8 mm diameter, 151 mm length
- Triple-strand graft: 9.9 mm diameter, 98 mm length
- Quadruple-strand graft: 11.4 mm diameter, 74 mm length
These graft sizes are compatible with the needs of ACL surgery, PCL reconstruction and combined procedures such as ACL and anterolateral ligament reconstruction.
Potential clinical value
According to the study’s anatomical findings, the RF tendon provides:
- Adequate length for single-bundle and multi-bundle reconstructions
- Sufficient diameter when increased stability is required
- A viable alternative in revision cases, especially when other graft sources (hamstrings, patellar tendon) are unavailable or previously harvested
Because harvesting targets only the superficial tendon layer, the deeper quadriceps layers remain intact, which may help preserve knee extensor function.
Practical surgical landmarks for safe harvesting
The study provides clear, reproducible surface landmarks to guide surgeons during RF tendon harvest .
The harvest window
The target zone lies between:
- 22 mm above the patella (distal fusion), and
- 58 mm above the patella (proximal fusion)
Within this window, the superficial RF layer separates cleanly from the deeper quadriceps layers. A 3–4 cm skin incision centered over this area provides reliable access.
Importance of tendon orientation
The RF tendon fibres run obliquely from medial-distal to lateral-proximal. Advancing the tendon harvester along this natural direction reduces the risk of fibre damage and ensures a complete graft.
Intraoperative verification
A simple, tactile check helps confirm correct placement:
- If the surgeon can insert a fingertip between the superficial and deep layers at the proximal zone, the plane is correct.
- If not, repositioning is required to avoid premature detachment.
These landmarks and checks improve safety and reproducibility, supporting the tendon’s use in standard surgical practice.
Preservation of knee function and donor site considerations
The study discusses theoretical advantages linked to preserving the deeper quadriceps layers and retaining most rectus femoris fibres.
Potential benefits
Harvesting only the superficial layer may:
- Reduce anterior knee pain compared with traditional quadriceps tendon harvest
- Protect the extensor mechanism by sparing deeper fibres
- Maintain good functional outcomes, supported by the muscle’s ability to compensate through other quadriceps heads
Donor site morbidity
The authors note that definitive evidence on postoperative strength and function requires dedicated clinical studies. However, existing clinical observations cited in the study suggest that removing part of the rectus femoris does not significantly affect return to sport or daily activities, particularly when other quadriceps muscles compensate.
Preservation of hamstrings
Using the RF tendon also leaves hamstring tendons untouched, which may benefit individuals who rely on medial hamstring stability, such as athletes with combined ACL and medial collateral ligament injuries.
Conclusion & Findings
The rectus femoris tendon shows a reliable anatomical structure, well-defined harvest landmarks and suitable dimensions for knee ligament reconstruction. The findings of the study support its use as a versatile autograft option in both primary and revision surgery.
To explore more scientific work on knee surgery anatomy, consider reading the other scientific publications published by Professor Etienne Cavaignac. For personalised care or surgical expertise, Professor Cavaignac remains a highly trusted specialist in knee surgery and sports traumatology.