The anterior cruciate ligament is essential for knee stability, particularly during rotational and pivoting activities. Surgical reconstruction is indicated in young, active individuals with symptomatic instability. Graft selection remains a subject of debate. While hamstring and BPTB grafts are widely used, each has associated drawbacks such as hamstring weakness, anterior knee pain, and kneeling discomfort.

The quadriceps tendon autograft, first described in the 1970s, has re-emerged as a reliable alternative with evolving minimally invasive harvesting techniques and improved fixation methods.

Aim

To assess the clinical and functional outcomes, rate of return to sports, and graft-related complications following anterior cruciate ligament reconstruction using a central quadriceps tendon autograft.

Methods

Study design and setting, patients, preoperative assessment, surgical technique, postoperative rehabilitation, outcome measures, and statistical analysis are described.

Study Design

This was a prospective observational study done over a period of 18 months from January 2024 to July 2025 conducted in the Department of Orthopaedics at Tertiary Care Hospital, Surat.

Study Population

All the patients who had  ACL tear and admitted in Department of Orthopaedics at Tertiary Care Hospital, Surat, Gujarat, during the mentioned study period and fulfilling the selection criteria mentioned below were recruited for the study.

Study Duration: 18 months

Inclusion criteria

  Confirmed ACL Tear

• Patients with complete or partial anterior cruciate ligament rupture confirmed by MRI or arthroscopy.

  Age Range

• Typically 18–45 years (skeletally mature adults).
• Younger patients may be considered if growth plates are closed; older patients should have good functional demand.

  Functional Instability

• Patients experiencing knee instability, giving way, or recurrent episodes during daily activities or sports.

  Activity Level

• Moderate to high activity individuals, including athletes or physically active patients who require knee stability.

  Suitable Quadriceps Tendon

• Adequate central quadriceps tendon thickness (usually ≥7 mm) confirmed by preoperative imaging or intraoperative assessment.
• Intact extensor mechanism without prior quadriceps tendon injury.

  Primary or Revision ACL Reconstruction

• Can be used for primary ACL reconstruction.
• Suitable for revision cases where hamstring or patellar tendon grafts are unavailable or previously used.

  Patient Consent

• Informed consent for autograft harvesting, including understanding potential donor site morbidity (e.g., anterior knee pain, quadriceps weakness).

  Time from Injury

• Typically chronic or acute ACL tear, provided there is no significant arthritis or multi-ligament instability that contraindicates isolated ACL reconstruction.

  General Health Criteria

• No systemic conditions affecting healing (e.g., uncontrolled diabetes, immunodeficiency).
• No active infection in the knee or systemic infection.

  Willingness for Postoperative Rehabilitation

• Ability and commitment to follow standard ACL rehabilitation protocol for optimal outcome.

Exclusion criteria

  Skeletally Immature Patients

Open growth plates (physis) that could be damaged during graft harvesting or tunnel drilling.

  Previous Quadriceps Tendon Injury or Surgery

History of quadriceps tendon rupture, tear, or prior harvesting for surgery.

Scarring or tendon weakness that would compromise graft quality.

  Severe Osteoarthritis or Knee Degeneration

Advanced cartilage loss (Kellgren-Lawrence grade III–IV) or degenerative changes that impair functional outcome after ACL reconstruction.

  Multi-Ligament Knee Injuries

Concomitant PCL, MCL, LCL, or posterolateral corner injuries requiring complex reconstruction unless staged or part of combined reconstruction protocol.

  Chronic Infection or Active Inflammatory Joint Disease

Septic arthritis or chronic osteomyelitis.

Rheumatoid arthritis or other inflammatory arthropathies affecting tendon healing.

  Systemic Health Issues Affecting Healing

Uncontrolled diabetes mellitus, immunosuppression, or vascular insufficiency.

Coagulopathy or bleeding disorders that increase surgical risk.

  Inadequate Quadriceps Tendon Size

Tendon thickness <7 mm or insufficient length for graft preparation.

Poor tissue quality observed intraoperatively.

  Neuromuscular Disorders

Conditions affecting quadriceps function or knee stability (e.g., polio, stroke, neuropathies).

  Previous Knee Surgery Limiting Graft Harvest

Patellar fracture or previous ACL reconstruction that compromises extensor mechanism or quadriceps tendon.

  Non-Compliance or Inability to Participate in Rehabilitation

Patients unwilling or unable to follow postoperative physiotherapy protocol.

Lifestyle or occupational limitations preventing proper recovery.

  Pregnancy

Elective surgery is usually postponed due to anesthesia and postoperative rehabilitation considerations.

Scoring System

Knee Society Score (KSS): Combines a Knee Score (pain, ROM, stability, alignment) and a Function Score (walking, stairs) for total 100 points each, widely used for arthroplasty outcomes.

Surgical technique

Anterior cruciate ligament reconstruction using a central quadriceps tendon  autograft is a standardized arthroscopically assisted procedure that is frequently combined with concomitant management of associated meniscal or chondral lesions whenever indicated. Our preference is to perform the procedure with the patient in the supine hanging leg position under spinal or general anaesthesia, using a central quadriceps tendon autograft. However, the procedure can also be performed using a single-bundle or double-bundle technique and with alternative fixation methods depending on surgeon preference and intraoperative findings. When the decision to proceed with ACL reconstruction is made preoperatively, central quadriceps  tendon harvesting is performed at the beginning of the procedure; however, in cases where the final decision is based on intraoperative assessment of ligament integrity and knee stability, graft harvesting may be performed later during the surgery.

Patient Position

The patient is positioned supine on a radiolucent operating table in hanging leg position under spinal or general anesthesia. A lateral post is placed at the level of the proximal thigh  used to maintain knee in  flexion and valgus position whenever required . A pneumatic tourniquet is applied to the proximal thigh but inflated only after limb exsanguination. The limb is prepared and draped in standard sterile fashion.

Fig.1- Hanging Leg position

Harvesting the central quadriceps tendon autograft

Graft Harvest

A double-bladed knife or scalpel is used to harvest the central third of the tendon. The graft is dissected proximally to obtain a length of approximately 7–9 cm.

The graft may be harvested as:

• All–soft tissue quadriceps tendon graft, or
• Bone–quadriceps tendon graft, where a rectangular bone block is harvested from the superior pole of the patella using an oscillating saw.

Hemostasis is achieved, and the donor site is irrigated.

Fig.2- Graft Preparation

The common femoral tunnel preparation 

The femoral tunnel is prepared using an anatomic anteromedial portal technique. The knee is flexed to 120–130° to prevent posterior wall blowout and allow accurate tunnel placement. After debridement of ACL remnants, the native femoral ACL footprint is identified using landmarks such as the resident’s ridge and posterior cartilage margin.

A guide pin is placed at the center of the femoral footprint through the anteromedial portal, ensuring adequate posterior wall preservation. A cannulated reamer matching the graft diameter (usually 8–10 mm) is used to drill the femoral tunnel to a depth of 25–30 mm under direct arthroscopic visualization. Tunnel integrity and position are confirmed, and a shuttle suture is passed for graft passage.

The tibial tunnel for ACL    

With the knee flexed to 90°, residual ACL fibers are debrided to expose the native tibial footprint, located anterior to the tibial spine, medial to the anterior horn of the lateral meniscus, and posterior to the intermeniscal ligament. A tibial aiming guide set at 55–60° is positioned at the center of the footprint. A guide wire is passed and confirmed arthroscopically to avoid roof impingement. Over the guide wire, a cannulated reamer matching the graft diameter (8–10 mm) is used to create the tibial tunnel. Tunnel position and smoothness are confirmed, and a shuttle suture is passed for graft passage.

Fig.3- Intra-operative photo

Graft preparation

The harvested central quadriceps tendon graft is cleared of excess soft tissue and measured for length and diameter. The graft length is usually 7–9 cm, with a diameter of 8–10 mm. Both ends of the graft are secured using Krackow or whip-stitch sutures with high-strength non-absorbable sutures. The prepared graft is kept moist in saline until implantation.

Graft fixation

The graft is passed through the tibial tunnel into the femoral tunnel.

Femoral fixation is achieved using a suspensory fixation device or interference screw, depending on graft type.
Tibial fixation is performed using an interference screw with the knee held in 20–30° of flexion under appropriate graft tension. The knee is cycled to remove graft creep before final fixation, and stability is reassessed.

Fig.4- Clinical photo

Closure

After completion of graft fixation and confirmation of knee stability, meticulous hemostasis is achieved at the quadriceps tendon harvest site. The quadriceps tendon defect is closed using interrupted absorbable sutures, ensuring approximation without excessive tension. The paratenon is carefully repaired in a continuous or interrupted manner to restore the tendon gliding surface and minimize postoperative adhesions and anterior knee pain.

Subcutaneous tissues are closed with absorbable sutures, followed by skin closure using interrupted or subcuticular sutures as per surgeon preference. Arthroscopic portal sites are closed with absorbable sutures after thorough joint lavage and evacuation of fluid. A sterile dressing is applied over all incisions, and a compression bandage is placed to reduce postoperative swelling. A knee brace may be applied depending on the rehabilitation protocol.

REHABILITATION PROTOCOL

                                                                         CASE-1

Fig.5                                                                               Fig. 6

Fig. 7                                                                     Fig.8

Fig.10

PRE-OPERATIVE MRI

Fig.11- Pre-op Xray

Fig.12- Post-op Xray

Fig.13

Fig.14

Fig.15

RESULT

The functional outcomes of anterior cruciate ligament reconstruction using central quadriceps tendon autograft are generally favourable; however, results may vary depending on factors such as patient age, activity level, graft size, surgical technique, associated injuries, and adherence to rehabilitation protocols. A summary of commonly reported outcomes is presented below:

1.      Pain Relief

Most patients experience significant reduction in knee pain following surgery. Postoperative pain typically decreases within the first few weeks, with continued improvement as graft incorporation and rehabilitation progress.

2.      Improved Knee Stability and Function

Restoration of anteroposterior and rotational knee stability is consistently achieved. Improvements in functional scores and range of motion are commonly reported. Return to daily activities is usually achieved within 3–6 months, while return to sports may take 6–9 months, depending on rehabilitation and activity demands.

3.      Graft Incorporation and Integrity

central quadriceps tendon autografts demonstrate good biological incorporation and remodeling. However hamstring autograft has reported graft failure or re-rupture rates range from approximately 5–15%, influenced by patient-related factors such as high-demand sports participation, early return to activity, and inadequate rehabilitation.

4.      Patient Satisfaction

High levels of patient satisfaction are reported following central quadriceps tendon autograft ACL reconstruction. Most patients are able to return to pre-injury levels of work and recreational activities, with many resuming sports participation.

5.      Predictors of Success

·        Positive Factors: Younger age, adequate graft diameter, proper tunnel placement, early supervised rehabilitation, and absence of associated ligament injuries.

·        Negative Factors: Older age, high body mass index, small graft diameter, poor neuromuscular control, associated meniscal or cartilage injuries, and non-compliance with rehabilitation protocols.

6.      Long-Term Outcomes

Long-term studies show sustained knee stability and functional improvement in most patients. Although degenerative changes such as osteoarthritis may develop over time, particularly in the presence of meniscal injury, functional outcomes generally remain satisfactory.

7.      Rehabilitation
A structured and progressive rehabilitation program is critical to achieving optimal outcomes. Emphasis is placed on early range of motion, quadriceps and hamstring strengthening, proprioceptive training, and gradual return to sports-specific activities.

DISCUSSION

The central quadriceps tendon autograft has emerged as a reliable option for anterior cruciate ligament reconstruction due to its favorable functional outcomes and low donor-site morbidity. Functionally, patients demonstrate significant improvement in knee stability, with postoperative Lachman and pivot shift tests showing results comparable to bone–patellar tendon–bone and hamstring tendon grafts. Instrumented laxity measurements typically indicate minimal side-to-side differences.

CONCLUSION

The use of central quadriceps tendon autograft for ACL reconstruction allowed us to reproduce a thicker graft which showed better graft strength and resistance to failure. Small-sized thinner grafts were associated with higher failure rates that represented a major limitation in other studies harvesting a double-stranded hamstring grafts with a diameter around 7 mm . The use of a central quadriceps tendon autograft for ACL reconstruction is a safe and effective technique that provides a thick, strong graft with excellent biomechanical properties. It results in high functional outcomes, improved knee stability, and a high rate of return to pre-injury activity, while minimizing donor-site morbidity and anterior knee pain. This graft represents a reliable alternative to hamstring and patellar tendon autografts, particularly in patients where graft size or anterior knee discomfort is a concern.

REFERENCES

1. Waldén M, Hägglund M, Werner J, Ekstrand J (2011) The epidemiology of anterior cruciate ligament injury in football (soccer): a review of the literature from a gender-related perspective. Knee Surg Sports Traumatol Arthrosc 19:3–10 [DOI] [PubMed] [Google Scholar]
2. Herzog MM, Marshall SW, Lund JL, Pate V, Mack CD, Spang JT (2018) Trends in incidence of ACL reconstruction and concomitant procedures among commercially insured individuals in the United States, 2002–2014. Sports health 10(6):523–531 [DOI] [PMC free article] [PubMed] [Google Scholar]
3. Wiggins AJ, Grandhi RK, Schneider DK, Stanfield D, Webster KE, Myer GD (2016) Risk of secondary injury in younger athletes after anterior cruciate ligament reconstruction: a systematic review and meta-analysis. Am J Sports Med 44(7):1861–1876 [DOI] [PMC free article] [PubMed] [Google Scholar]
4. Nyland J, Moatshe G, Martin R (2023) Combined ACL and anterolateral ligament reconstruction: time to pivot and shift the focus? Knee Surg Sports Traumatol Arthrosc 31(2):373–375 [DOI] [PubMed] [Google Scholar]
5. Daggett M, Busch K, Sonnery-Cottet B (2016) Surgical dissection of the anterolateral ligament. Arthrosc Tech 5(1):e185–e188 [DOI] [PMC free article] [PubMed] [Google Scholar]
6. Claes S, Vereecke E, Maes M, Victor J, Verdonk P, Bellemans J (2013) Anatomy of the anterolateral ligament of the knee. J Anat 223(4):321–328 [DOI] [PMC free article] [PubMed] [Google Scholar]
7. Vincent JP, Magnussen RA, Gezmez F, Uguen A, Jacobi M, Weppe F, Neyret P (2012) The anterolateral ligament of the human knee: an anatomic and histologic study. Knee Surg Sports Traumatol Arthrosc 20(1):147–152 [DOI] [PubMed] [Google Scholar]
8. Fernandes JC, Pinho AR, Pereira PA, Madeira MD, Raposo FA, Sousa AN, Lobo JM (2023) Anterolateral ligament of the knee—Cadaver study in a Caucasian population. Revista espanola de cirugia ortopedica y traumatologia 67(2):134–138 [DOI] [PubMed] [Google Scholar]
9. Chahla J, Menge TJ, Mitchell JJ, Dean CS, LaPrade RF (2016) Anterolateral ligament reconstruction technique: an anatomic-based approach. Arthrosc Tech 5(3):e453–e457 [DOI] [PMC free article] [PubMed] [Google Scholar]
10. Lau BC, Rames J, Belay E, Riboh JC, Amendola A, Lassiter T (2019) Anterolateral complex reconstruction augmentation of anterior cruciate ligament reconstruction: biomechanics, indications, techniques, and clinical outco