Chronic Quadriceps Tendon Rupture: A Case Study in Surgical Reconstruction
The quadriceps tendon connects the quadriceps muscles at the front of the thigh to the patella, helping the knee straighten during walking, running, jumping and other movements. When the tendon ruptures, the knee's extensor mechanism can be significantly affected, making it difficult to actively straighten the knee or perform a straight-leg raise.
Acute quadriceps tendon ruptures can often be repaired directly when treatment is provided promptly. However, treatment becomes more challenging when a rupture remains untreated for an extended period. Over time, the tendon can retract, shorten and develop changes that make direct repair more difficult.
A 2022 case report from Singapore described the surgical reconstruction of a chronic quadriceps tendon rupture in a 19-year-old man who had previously participated in parkour. The authors described a modified reconstruction using suture anchors and a peroneal tendon allograft incorporated through a basket-weave technique.
Dr Wang Lushun of Arete Orthopaedic Centre was one of the three contributors to the research, alongside Daniel Chris Lee and Yasser Hasan. At the time, the authors were affiliated with the Department of Orthopedics at the National University of Singapore.
What Is a Quadriceps Tendon Rupture?
The quadriceps tendon is part of the knee's extensor mechanism, which allows the knee to straighten.
The extensor mechanism consists of structures including:
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Quadriceps muscles
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Quadriceps tendon
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Patella
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Patellar tendon
Together, these structures transmit force from the thigh muscles through the knee to the lower leg.
A rupture of the quadriceps tendon can interrupt this mechanism. A complete rupture may therefore make it difficult or impossible to actively straighten the knee.
How Does a Quadriceps Tendon Rupture Occur?
Quadriceps tendon ruptures can occur when the tendon is subjected to a strong force while the quadriceps muscle is contracting.
Possible mechanisms include:
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Sudden jumping or landing
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Sports injuries
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Falls
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Direct trauma
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Forceful eccentric muscle contraction
The research notes that quadriceps tendon ruptures are relatively uncommon and typically occur in a middle-aged population. Tendons affected by degeneration, fatty infiltration or other structural changes may also be more vulnerable to rupture. Certain medical conditions, including endocrine and renal disorders, inflammatory diseases and long-term steroid use, have also been associated with tendon vulnerability.
The case described in this research was unusual because the patient was only 19 years old and had a history of parkour rather than the more typical age profile described in the literature.
What Makes a Chronic Quadriceps Tendon Rupture Different?
Timing is important when treating a tendon rupture.
The researchers considered a rupture chronic when more than three weeks had passed between the injury and intervention. During this period, changes can occur in the tendon and surrounding tissues.
A chronic rupture may involve:
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Tendon shortening
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Tendon retraction
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Scar tissue
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Fatty infiltration
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A gap between the tendon ends
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Reduced quality of the remaining tendon
These changes can make it difficult to simply bring the original tendon ends back together.
In some chronic injuries, the gap between the tendon ends can become substantial, requiring additional reconstruction or graft augmentation rather than straightforward repair.
The Patient's Four-Year History of Knee Symptoms
The case involved a 19-year-old man who had a four-year history of left anterior knee pain.
Before his symptoms developed, he regularly participated in parkour, an activity involving repeated high-impact landings and movements.
His knee pain and weakness eventually forced him to stop participating in the sport. However, he did not initially seek medical treatment.
He eventually sought medical attention during his national service because his symptoms were affecting his physical training.
What Did the Initial Assessment Show?
At examination, the patient had:
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Wasting of the left quadriceps muscle
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Pain around the quadriceps insertion at the upper part of the patella
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Reduced knee extension strength
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An extension lag of 20 degrees
His knee could still be passively moved through its range, but active extension was weakened.
Radiographs showed chronic calcification within the tendon near the upper pole of the patella.
An MRI scan showed swelling and oedema around the quadriceps tendon insertion, but did not initially demonstrate an acute tear.
The initial clinical impression was chronic quadriceps tendinopathy, and the patient began physiotherapy.
How Did the Condition Progress?
The patient's condition subsequently worsened.
He developed approximately six weeks of new inability to extend the knee and denied any new traumatic injury.
On examination, there was:
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Mild knee effusion
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A palpable gap at the quadriceps insertion
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Complete loss of the extensor mechanism
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Inability to perform or maintain a straight-leg raise
X-rays showed patella baja, where the patella sits lower than its expected position.
An urgent MRI then demonstrated a high-grade tear of the distal quadriceps tendon.
The patient was diagnosed with a chronic quadriceps tendon rupture and underwent surgical reconstruction.
Why Was Reconstruction More Complex Than a Standard Repair?
An acute quadriceps tendon rupture generally involves relatively fresh tendon ends that can be brought together and repaired.
In a chronic rupture, the tendon may have become:
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Retracted
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Shortened
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Scarred
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Structurally compromised
In this case, the chronic rupture occurred against a background of longstanding tendinopathy. The researchers therefore determined that additional graft augmentation was needed to reinforce the repair.
What Surgical Technique Was Used?
The researchers described a modified reconstruction involving:
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Suture anchors
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FiberTape sutures
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A peroneal tendon allograft
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A modified basket-weave technique
The operation began with an arthroscopic assessment of the knee.
The quadriceps tendon insertion appeared thin and unhealthy, with evidence of fatty infiltration. The cruciate ligaments, cartilage and menisci were otherwise reported to be intact.
The surgeons then proceeded with open reconstruction.
Step 1: Removing Unhealthy Tendon
The surgeons exposed the ruptured quadriceps tendon through a midline incision.
Unhealthy tendon tissue was removed until healthy bleeding tissue was reached.
The upper surface of the patella was also prepared to provide an appropriate surface for reconstruction.
This step was important because attempting to secure a reconstruction to poor-quality tissue may compromise the repair.
Step 2: Preparing the Quadriceps Tendon
Four FiberTape sutures were passed through the proximal quadriceps musculotendinous junction using a Krackow locking configuration.
This created a strong suture construct that could be used to secure the tendon during reconstruction.
Step 3: Creating a Bone Tunnel
A horizontal tunnel was created through the upper part of the patella.
The tunnel measured approximately 5 mm in diameter.
A peroneal tendon allograft measuring 5 mm by 280 mm was then passed through the tunnel.
Step 4: Fixing the Quadriceps Tendon
The quadriceps tendon was brought down to its attachment on the patella and secured using two suture anchors.
The anchors were positioned obliquely to improve their pull-out strength while avoiding interference with the horizontal bone tunnel used for the graft.
Step 5: Creating the Basket-Weave Reconstruction
The two ends of the allograft were passed repeatedly through the quadriceps tendon using a weaving technique.
The graft was then secured and further reinforced using FiberWire sutures.
The researchers described this as a modified Pulvertaft-style basket weave.
The purpose was to reinforce the repaired tendon and provide additional structural support.
Why Use an Allograft?
An allograft is tissue obtained from a donor rather than from the patient's own body.
In chronic quadriceps tendon ruptures, graft augmentation may be considered when the remaining tendon is shortened or of poor quality.
In this case, the allograft was used to reinforce the reconstruction rather than relying solely on the patient's damaged native tendon.
The authors suggested that incorporating the graft could increase the collagen content and tensile strength of the overall reconstruction.
Why Were Suture Anchors Used?
The authors identified several potential advantages of suture anchors in their technique.
First, they allowed the quadriceps tendon to be approximated to the patella with controlled tension.
Second, suture anchors avoided the need for full-length transosseous tunnels through the patella, which the authors noted could potentially increase the risk of bone fracture.
The use of shorter anchors also allowed a separate horizontal tunnel to be created for the allograft.
What Happened Immediately After Reconstruction?
Following reconstruction, the surgeons observed:
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Restoration of quadriceps tendon tension
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Restoration of patellar height
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No gapping of the reconstruction during passive knee flexion
The knee could be passively flexed to approximately 80 degrees intraoperatively without the reconstruction opening up.
What Was the Recovery Protocol?
The postoperative rehabilitation programme was deliberately protective.
For the first month:
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The knee was immobilised in extension
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The patient was non-weight-bearing
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A back slab was used
After one month, a knee brace was introduced to allow controlled movement.
The range of motion was increased by 30-degree increments every two weeks.
The brace was removed at approximately three months after surgery.
The exact rehabilitation programme after a quadriceps tendon reconstruction can vary depending on the surgical technique, tissue quality and surgeon's assessment.
What Were the Patient's Outcomes?
The patient demonstrated progressive recovery.
At Six Months
The patient had:
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Full muscle power
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Knee range of motion from 0° to 90°
At Sixteen Months
The patient was:
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Asymptomatic
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Participating in high-impact sports
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Able to achieve a knee range of motion from 0° to 140°
This represented a return to his pre-morbid range of motion according to the case report.
Why Is This Case Significant?
Chronic quadriceps tendon ruptures are uncommon, and the literature on their treatment is limited compared with more frequently encountered knee injuries.
The authors noted that chronic ruptures tend to have less favourable outcomes than acute repairs because the tendon can become retracted and structurally compromised.
This case is notable because:
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The patient was unusually young
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The rupture had been neglected for an extended period
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There was underlying chronic tendinopathy
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Reconstruction required graft augmentation
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The patient eventually returned to high-impact activity
However, these findings represent one patient's outcome and should not be interpreted as evidence that the technique will produce the same result in every chronic quadriceps tendon rupture.
Why Early Diagnosis of Quadriceps Tendon Rupture Matters
The case also highlights the importance of recognising progressive weakness and changes in knee function.
A chronic tendon rupture can become more difficult to repair as the tendon retracts and its quality deteriorates.
Potential warning signs include:
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Increasing anterior knee pain
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Progressive quadriceps weakness
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Difficulty straightening the knee
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Increasing extension lag
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Difficulty performing a straight-leg raise
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A noticeable change in the position of the patella
A sudden inability to actively straighten the knee should be medically assessed promptly.
Can a Quadriceps Tendon Rupture Be Treated Without Surgery?
Treatment depends on the severity and circumstances of the injury.
A complete rupture that causes loss of the extensor mechanism generally requires surgical treatment to restore function. The research specifically involved a chronic rupture with complete loss of the extensor mechanism.
Partial injuries or other tendon conditions may be managed differently depending on their severity and the patient's symptoms.
How Is a Quadriceps Tendon Rupture Diagnosed?
Assessment may involve:
Physical Examination
A doctor may assess:
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Active knee extension
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Straight-leg raise ability
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Extension lag
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Quadriceps strength
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Palpable gaps around the tendon
X-Rays
X-rays may show changes such as:
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Patella baja
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Other bone or alignment abnormalities
MRI
MRI can provide more detailed information about:
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Tendon integrity
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Tendon retraction
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Tendinopathy
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Soft tissue changes
The case report used both radiographs and MRI to investigate the patient's progressive symptoms.
What Can Patients Learn From This Research?
The case provides several useful points for patients with persistent knee symptoms:
Persistent pain should not always be ignored
Long-standing knee pain accompanied by weakness may indicate an underlying tendon problem requiring assessment.
Loss of active knee extension is important
Difficulty straightening the knee or performing a straight-leg raise can indicate disruption of the extensor mechanism.
Chronic injuries can be more difficult to repair
Once a tendon rupture becomes chronic, the tissue may retract and deteriorate, potentially requiring graft augmentation or other reconstructive techniques.
Treatment needs to be individualised
The technique described in this research was developed for a specific chronic rupture and should not be considered appropriate for every quadriceps tendon injury.
Rehabilitation is a major part of recovery
The patient's reconstruction was followed by several months of protected rehabilitation before progressively returning to high-demand activities.
A 2022 Singapore case report described the reconstruction of a chronic quadriceps tendon rupture in a 19-year-old former parkour participant. Because the injury had become chronic and the tendon showed longstanding pathological changes, the authors used a modified reconstruction combining suture anchors with a peroneal tendon allograft incorporated through a basket-weave technique.
The patient underwent protected rehabilitation and achieved full muscle power at six months. At 16 months, he was asymptomatic, had regained a knee range of motion of 0° to 140° and had returned to high-impact sports.
The research demonstrates the potential of this reconstructive approach in a specific chronic quadriceps tendon rupture. However, as a single case report, it does not establish the technique as superior to other methods or predict outcomes for all patients.
Early assessment of persistent knee pain, progressive weakness or difficulty straightening the knee remains important because chronic tendon ruptures can become more challenging to reconstruct over time.
Research Reference
Lee DC, Hasan MY, Wang L. Parkour and chronic quadriceps tendon rupture: A novel technique for repair and reconstruction of the extensor mechanism utilising suture anchors and allograft augmentation. Annals of Clinical Case Reports. 2022;7:2149. DOI: 10.25107/2474-1655.2149.
This article is for general information only and should not replace medical advice from a qualified healthcare professional.
