Quadriceps tendonitis

1. High-Yield Summary

• Condition Definition: Quadriceps tendinitis (more accurately termed quadriceps tendinopathy or proximal jumper’s knee) is an insertional overuse disorder of the extensor mechanism characterized by degenerative collagen breakdown, hypervascularity, and failed tendon healing at the superior pole of the patella, rather than acute inflammatory cell infiltration.
• Demographics & Epidemiology: Represents approximately 5% of all extensor mechanism tendinopathies (significantly less common than patellar tendinopathy); characteristically affects mature jumping, sprinting, and weightlifting athletes (volleyball, basketball, Olympic weightlifting) aged 25 to 40 years, with a male-to-female predominance of 3:1.
• Primary Diagnostic Hallmark: Well-localized point tenderness at the superior border of the patella exacerbated by active knee extension under load, deep squatting, and the single-leg decline squat test, with structural confirmation via high-frequency musculoskeletal ultrasound or sagittal magnetic resonance imaging (MRI).
• Evidence-Based Conservative Care: First-line structured rehabilitation succeeds in 80% to 90% of cases using progressive mechanical loading (isometric analgesia transitioning to heavy slow resistance training) combined with kinetic chain correction (hip extensor strengthening and ankle dorsiflexion mobilization).
• Absolute Clinical Contraindication: Intratendinous corticosteroid injections are strictly contraindicated due to direct tenocyte toxicity, rapid collagen necrosis, and a markedly heightened risk of catastrophic extensor mechanism rupture during subsequent eccentric contraction.
• Operative Threshold: Surgical intervention (open or endoscopic debridement of angiofibroblastic degenerated tissue, superior patellar pole decortication, and longitudinal tenotomies) is strictly reserved for refractory cases failing at least 6 months of supervised, compliant progressive loading rehabilitation.

2. Anatomy

The quadriceps tendon is the massive terminal confluence of the anterior thigh extensor musculature that inserts onto the proximal base and anterior third of the patella. Understanding its laminar architecture, enthesis microanatomy, and neighboring synovial compartments is critical for differentiating pathology and avoiding operative complications.

Laminar Architecture & Footprint

The quadriceps tendon is a multi-layered composite aponeurosis typically organized into three distinct anatomical laminae:

• Superficial Layer: Formed by the rectus femoris aponeurosis. Its central fibers insert onto the anterior superior cortex of the patella, while thin superficial prepatellar fibers traverse uninterrupted across the anterior surface of the patella to merge with the anterior fibers of the patellar tendon, forming the continuous anterior extensor retinaculum.
• Intermediate Layer: Formed by the broad conjoined aponeuroses of the vastus lateralis and vastus medialis. This layer provides the greatest structural tensile mass and inserts directly into the central and anterior superior margin of the patella.
• Deep Layer: Formed entirely by the vastus intermedius tendon. It inserts onto the posterosuperior articular-adjacent rim of the patellar base, intimately bordering the suprapatellar synovial pouch and prefemoral fat pad.

The insertional footprint measures 5 to 6 cm in transverse width and 6 to 8 mm in sagittal thickness. Tendon thickness tapers as it approaches the proximal muscle bellies. The vastus medialis oblique (VMO) and vastus lateralis insert into the medial and lateral borders of the patella, providing dynamic coronal plane stabilization against lateral patellar tilt or subluxation.

Vascular Watershed & Enthesis Microanatomy

Vascular perfusion to the quadriceps tendon is supplied by the peritendinous vascular ring derived from anastomoses between the supreme genicular artery, lateral superior genicular artery, and medial superior genicular artery. While the superficial and intermediate laminae maintain moderate peritendinous vascularity, the deep vastus intermedius insertional enthesis constitutes a relative “watershed zone” of hypovascularity. Under repetitive mechanical compression against the superior trochlea during deep flexion, this zone suffers local tissue hypoxia, predisposing it to mucoid matrix degeneration and impaired intrinsic reparative remodeling.

Danger Zones & Internervous Intervals

3. Pathogenesis

Quadriceps tendinitis is a misnomer historically applied to a condition that is pathophysiologically a non-inflammatory degenerative tendinopathy (tendinosis). The condition develops when repetitive biomechanical tensile strain, combined with deep flexion compressive loads, exceeds the cellular reparative capacity of tenocytes.

Biomechanical Overload & Compressive Impingement

During running, rapid deceleration, and the takeoff and landing phases of jumping, the quadriceps extensor mechanism experiences forces exceeding 6 to 8 times body weight. These forces are transmitted across the quadriceps tendon enthesis during high-load eccentric muscle contractions. Furthermore, when the knee flexes beyond 60 degrees, the deep fibers of the vastus intermedius wrap tightly over the superior patellar rim and the proximal trochlea. This kinematics generates substantial compressive and shear stress at the deep enthesis, superimposed upon tensile loads. This dual-load environment (tensile pull plus compressive contact pressure) is the primary mechanical trigger for insertional tendinopathy.

The Tendinopathy Continuum Model

According to the validated continuum model proposed by Cook and Purdam, the disease evolves across three interconnected stages:

• Reactive Tendinopathy: An acute, non-inflammatory proliferative cellular response to sudden volume or intensity spikes. Tenocytes undergo cell swelling and produce hydrophilic large proteoglycans (aggrecan and versican), drawing water into the ground substance. This produces visible tendon thickening on imaging that functions biomechanically to decrease stress per unit area.
• Tendon Disrepair: Continued unmanaged loading leads to worsening matrix breakdown. Collagen type I fibrillar architecture becomes disrupted, chondrocytic metaplasia occurs, and tenocytes produce irregular collagen type III. Small vessel ingrowth and accompanying sensory nerve sprouting (neovascularization) begin to invade the previously aneural, avascular tendon core.
• Degenerative Tendinopathy: Chronic irreversible structural changes marked by extensive tenocyte apoptosis, cellular breakdown, and large acellular mucoid pools. Dense ingrowth of sensory nerve fibers expressing Substance P and calcitonin gene-related peptide (CGRP) propagates chronic mechanical nociception. At this stage, reversibility is minimal, and the structural integrity of the extensor mechanism is compromised.

4. Natural History

Quadriceps tendinopathy accounts for approximately 5% to 10% of extensor mechanism tendinopathies, occurring far less frequently than patellar tendinopathy (which accounts for ~65% to 80%) but presenting significant functional impairment when established. It is predominantly encountered in athletic cohorts engaged in repetitive jumping, deep knee squatting, and sudden deceleration, notably volleyball, basketball, football, Olympic weightlifting, and CrossFit.

Unlike patellar tendinopathy, which peaks in teenage and collegiate athletes (ages 16 to 24), quadriceps tendinopathy characteristically manifests in mature adult athletes aged 25 to 40 years. This older demographic reflects cumulative lifetime microtrauma, age-dependent loss of tendon elasticity, and gradual mucopolysaccharide matrix degeneration. Males are affected approximately three times more frequently than females, likely due to higher absolute jumping velocity, greater quadriceps muscle mass, and greater knee extensor torque generation.

If left untreated or improperly managed with continued high-impact loading, the natural history is characterized by progressive functional deterioration. Intermittent post-exercise soreness advances to persistent pain during athletic performance, followed by daily pain during stair descent, prolonged sitting (“theater sign”), and rising from a chair. In severe end-stage degenerative tendinosis, extensive structural collagen failure weakens the tendon, predisposing the patient to complete, macroscopic rupture of the quadriceps tendon upon sudden eccentric loading (e.g., slipping on stairs or missing a step), transforming a chronic overuse condition into an acute orthopaedic surgical emergency.

5. Clinical Presentation

Patient History

Patients typically describe an insidious, progressive onset of well-localized aching discomfort at the superior border of the patella. Key historical elements that establish the diagnosis and exclude competing pathologies include:

• Load-Dependent Pain Onset: Pain correlates directly with activities that increase extensor mechanism tensile and compressive load, such as jumping, rapid cutting, decelerating from a sprint, and deep squatting beyond 90 degrees.
• Warm-Up Phenomenon: In early stages, patients report that the knee feels stiff and painful during the initial 5 to 10 minutes of exercise, improves noticeably as the tendon warms up, and then recurs severely several hours post-exercise or the following morning.
• Functional Mechanical Symptoms: Pain is exacerbated by descending stairs (eccentric quadriceps load) much more than ascending stairs. True mechanical instability, catching, or true locking is absent, distinguishing the condition from meniscal pathology or intra-articular loose bodies.
• Training Errors & Prior Injections: History typically reveals a recent increase in plyometric training volume, changes in training surfaces, or inappropriate prior treatments, particularly peritendinous or intratendinous corticosteroid injections.

Physical Examination

A systematic physical examination must differentiate quadriceps tendinopathy from patellofemoral pain syndrome, prepatellar bursitis, suprapatellar plica syndrome, and intra-articular pathology.

6. Imaging and Diagnostic Studies

Imaging serves to confirm clinical suspicion, assess the extent and depth of structural degeneration, rule out occult partial-thickness or complete tendon tears, and exclude intra-articular derangements.

Plain Radiography

Standard knee radiographs should include weight-bearing anteroposterior (AP), true lateral (30° flexion), and axial patellofemoral (Merchant or sunrise) views:

• Superior Patellar Enthesophytes: Prominent vertical traction spurs or osteophytes extending superiorly from the anterior base of the patella (the classic “tooth sign” on axial or lateral views).
• Cortical Sclerosis & Microcystic Changes: Cortical thickening, sclerosis, or microcystic lucency at the superior patellar margin indicating chronic enthesopathy and traction stress.
• Intratendinous Calcification: Punctate or linear heterotopic calcifications within the distal 2 cm of the quadriceps tendon substance.
• Differential Exclusion: Radiographs rule out patella alta/baja, bipartite patella (Type III superior-lateral), patellofemoral joint space narrowing, and osteochondral loose bodies.

Musculoskeletal Ultrasound (High-Resolution Diagnostic US)

Musculoskeletal ultrasound using high-frequency (12 to 18 MHz) linear transducers represents an ideal first-line imaging modality due to its dynamic capability, high spatial resolution, and low cost:

• Focal Hypoechogenicity: Loss of the normal hyperechoic parallel fibrillar tendon architecture, appearing as localized hypoechoic patches predominantly in the deep vastus intermedius insertion.
• Anteroposterior (AP) Tendon Thickening: Normal quadriceps tendon thickness at the enthesis is 6 to 8 mm. Pathologic tendinopathy typically displays focal swelling exceeding 9 to 11 mm.
• Power Doppler Hypervascularity: Pathologic neovessels (neovascularization) invading the deep tendon substance and peritendinous interface, correlating with active symptom generation.
• Cortical Entheseal Irregularity: Irregular, jagged osseous contours at the superior patellar footprint.

Magnetic Resonance Imaging (MRI)

MRI (1.5T or 3.0T) is the definitive gold standard for comprehensive anatomical staging, surgical planning, and ruling out full-thickness tendon failure:

• Sagittal T1-Weighted & Proton Density (PD) Sequences: Demonstrate fusiform thickening of the distal quadriceps tendon and loss of clean demarcation between individual laminae.
• Sagittal T2-Weighted Fat-Suppressed / STIR Sequences: Reveal focal, hyperintense fluid-like signal within the tendon substance, representing mucoid degeneration, matrix edema, and microtearing. Signal alteration is most frequent in the posterior/deep fibers adjacent to the bone.
• Bone Marrow Edema: T2/STIR hyperintensity within the superior pole of the patella reflects osseous traction stress and enthesopathy.
• Macroscopic Disruption Scrutiny: Verifies that the extensor mechanism remains in continuity and excludes partial-thickness or complete tendon rupture (which would present with wavy tendon retraction and extensive hemarthrosis).

7. Classification

Quadriceps tendinopathy is classified based on functional clinical staging systems modified from the original jumper’s knee framework proposed by Blazina et al., and subsequently refined by Roels and colleagues. This staging directly dictates nonoperative progression and determines when surgical intervention is indicated.

8. Treatment

The overarching philosophy in managing quadriceps tendinopathy is evidence-based, progressive mechanical loading to restore the load-bearing capacity of the extensor mechanism. Passive modalities and absolute rest are ineffective; the tendon must be systematically stimulated to promote matrix remodeling.

Medical & Nonoperative Management

Nonoperative management is the mandatory primary therapy and successfully resolves symptoms in 80% to 90% of patients. A four-phase loading paradigm represents the contemporary standard of care:

• Phase 1: Isometric Loading (Analgesia Phase):
  For patients with acute reactive flares or severe resting pain, heavy isometric knee extension holds are performed (e.g., seated leg extension machine or single-leg leg press held at 60 degrees of knee flexion). The protocol entails 5 sets of 45-second holds at 70% of maximum voluntary isometric contraction (MVIC), separated by 2-minute rests, 2 to 3 times daily. Heavy isometric contractions stimulate cortical muscle release, immediately downregulate pain via central and peripheral inhibitory mechanisms, and provide analgesia lasting 45 to 60 minutes.
• Phase 2: Heavy Slow Resistance (HSR) / Isotonic Strength Phase:
  Once baseline resting pain stabilizes (VAS ≤ 3/10 during daily activities), patients transition to heavy slow resistance training 3 days per week on alternate days. Exercises include leg press, bilateral hack squats, and barbell split squats. The protocol uses 4 sets of 6 to 8 repetitions with a controlled tempo: 3 seconds concentric, 3 seconds eccentric, and a 1-second pause at 80° to 90° flexion. Load is progressively increased from 70% to 85% of 1-repetition maximum (1RM). HSR delivers high mechanical tensile strain, stimulating tenocyte collagen synthesis and tendon matrix stiffening without high-velocity shear forces.
• Phase 3: Energy Storage & Plyometric Progression:
  Initiated only when quadriceps strength reaches ≥85% of the contralateral limb and HSR is performed pain-free. Introduces fast stretch-shortening cycle (SSC) exercises: jumping, box hops, bounding, and deceleration change-of-direction drills. Performed every 3 days to allow 72-hour collagen turnover cycles.
• Phase 4: Return-to-Sport Integration:
  Gradual reintroduction to sport-specific drills, scrimmages, and competitive play. Discharge criteria include: painless single-leg decline squat, quadriceps limb symmetry index (LSI) > 90% on isokinetic testing, and normalized VISA-P score (>80 points).

Kinetic Chain Rehabilitation: Isolated quadriceps strengthening fails if kinetic chain deficiencies remain uncorrected. Treatment must systematically address rectus femoris and hamstring flexibility deficits, strengthen the gluteus medius and maximus to correct dynamic knee valgus collapse, and restore ankle dorsiflexion mobility through gastrocnemius-soleus stretching and talocrural joint mobilization.

Biologics & Adjunctive Therapies: Extracorporeal shockwave therapy (focused ESWT, 2,000–2,500 pulses at 0.15–0.25 mJ/mm², weekly for 3–5 sessions) stimulates local cellular metabolism and downregulates nociceptive sensory neuropeptides. Platelet-rich plasma (PRP) injections (leukocyte-poor or leukocyte-rich) administered under ultrasound guidance directly into the degenerative hypocellular cleft have demonstrated variable clinical efficacy and may be considered as an adjunct in chronic recalcitrant tendinosis.

Absolute Contraindication to Corticosteroid Injections: Intratendinous or peritendinous corticosteroid injection must be avoided. Corticosteroids inhibit tenocyte proliferation, halt collagen and extracellular matrix synthesis, induce focal microvascular thrombosis, and dramatically increase the risk of catastrophic complete quadriceps tendon rupture.

Operative Management

Surgical management is indicated in fewer than 10% to 15% of patients who have exhausted a minimum of 6 months of structured, compliant rehabilitation. The primary surgical goals are:

• Excise diseased, non-viable angiofibroblastic degenerative tissue within the deep enthesis.
• Decompress the tendon footprint by resecting traction enthesophytes from the superior patellar pole.
• Stimulate biological healing through longitudinal tenotomies and decortication/microdrilling of the sclerotic osseous bed to recruit vascular progenitor cells.
• Preserve the structural continuity of the superficial extensor mechanism.

Open Debridement and Superior Patellar Decortication: A 5 to 6 cm longitudinal midline incision is centered over the superior pole of the patella. The paratenon is incised longitudinally. A longitudinal tenotomy is performed in line with the tendon fibers through the central rectus femoris. The tendon is retracted to expose the deeper vastus intermedius insertion. Diseased tissue—identified by its dull, yellow-gray, gelatinous, hypervascular appearance and loss of fibrillar tension—is sharply excised. Prominent traction osteophytes on the superior patellar rim are excised with a rongeur or burr, and the sclerotic footprint is gently decorticated or microdrilled with a 1.5 mm K-wire. If a significant insertional void is created, the tendon is re-anchored to the patella using nonabsorbable suture anchors. The longitudinal tenotomy is closed with absorbable sutures.

Endoscopic / Arthroscopic Tendon Debridement: Minimally invasive endoscopic debridement utilizes suprapatellar viewing and working portals. Under direct visualization, the retro-tendinous space and the deep vastus intermedius insertion are evaluated. A motorized shaver and radiofrequency probe are used to debride degenerate posterior fibers and resect superior patellar rim osteophytes, leaving the superficial rectus femoris fibers completely undisturbed. This approach minimizes postoperative scar formation and accelerates recovery.

Indications & Contraindications

9. Outcome

Clinical outcomes in quadriceps tendinopathy correlate strongly with adherence to progressive loading regimens and precision in surgical tissue debridement.

Patient-Reported Outcome Measures (PROMs)

The primary validated disease-specific outcome instrument is the Victorian Institute of Sport Assessment – Patellar score (VISA-P), which has been validated for proximal extensor mechanism tendinopathies. A score of 100 indicates asymptomatic, unrestricted function, while scores below 50 reflect severe disability. Other utilized metrics include the Knee Injury and Osteoarthritis Outcome Score (KOOS), the International Knee Documentation Committee (IKDC) subjective score, and the Tegner Activity Scale.

Conservative & Surgical Success Rates

• Nonoperative Results: Structured Heavy Slow Resistance (HSR) protocols yield good to excellent clinical success in 80% to 90% of athletes, with mean VISA-P scores improving from 48–55 at baseline to 82–92 at 12 to 24 weeks. Tendon structural remodeling on ultrasound lags behind clinical symptom resolution.
• Operative Results: In patients undergoing open or endoscopic debridement for refractory tendinopathy, good to excellent results are reported in 75% to 85% of cases. Complete pain relief is achieved in approximately 70% of athletes, with a marked reduction in pain during athletic exertion.
• Return-to-Sport Timelines: Nonoperative athletes completing an HSR program typically return to restricted sports participation at 8 to 12 weeks, achieving unrestricted competition between 16 and 24 weeks. Following surgical debridement, return to full athletic competition averages 6 to 9 months, depending on the extent of tendon excision and need for transosseous suture anchor repair.

10. Complications

Both nonoperative neglect and operative intervention carry distinct potential complications that must be anticipated, prevented, and systematically managed.

11. Pearls and Pitfalls

• The Full-Extension Palpation Pearl: Always examine and palpate the quadriceps tendon enthesis with the knee in completely relaxed, passive extension. In flexion, the tension of the intact superficial rectus femoris obscures focal point tenderness within the deeper degenerated vastus intermedius footprint.
• Kinetic Chain Restoration Pearl: Never limit rehabilitation to the extensor mechanism alone. Restoring full ankle dorsiflexion mobility (≥35° or ≥10 cm knee-to-wall lunge) and strengthening the hip external rotators and abductors reduces peak knee extensor deceleration torque by up to 25%.
• Superficial Fiber Preservation Pearl: During open surgical debridement, split the superficial rectus femoris longitudinally in line with its fibers and retract it laterally and medially. The pathology almost universally resides within the deep vastus intermedius insertion. Spoil none of the superficial continuity, avoiding extensor lag.
• The Corticosteroid Catastrophe Pitfall: Never administer a local corticosteroid injection into or adjacent to the quadriceps tendon for short-term pain relief before an athletic event. This practice induces rapid tenocyte apoptosis and collagenolysis, leading directly to catastrophic complete tendon rupture under high eccentric loads.
• The Complete Rest Pitfall: Avoid prescribing complete immobilization or prolonged total rest in a brace. Tendons require physiological mechanical tension to maintain matrix homeostasis; prolonged disuse induces muscle atrophy, reduces tendon stiffness, and accelerates matrix disrepair.
• The Premature Plyometrics Pitfall: Do not allow athletes to resume high-velocity jumping, bounding, or sprinting until they have completed a minimum of 6 to 8 weeks of pain-free Heavy Slow Resistance training and demonstrated a limb symmetry index > 85% on quadriceps dynamometry.

12. Controversy

Significant clinical controversies remain regarding optimal diagnostic thresholds, biological augmentations, and operative techniques in the management of quadriceps tendinopathy:

• Heavy Slow Resistance (HSR) vs. Isolated Eccentric Training: For decades, eccentric decline squatting was heralded as the gold standard for extensor tendinopathies. However, high-velocity eccentric movements generate high tendon shear forces and may provoke pain in deep flexion. Contemporary sports medicine increasingly favors Heavy Slow Resistance (HSR) protocols, which combine slow concentric and eccentric phases under heavy loads. HSR achieves equivalent clinical pain relief and functional recovery while inducing superior long-term collagen fibril remodeling and higher patient satisfaction.
• The Efficacy of Platelet-Rich Plasma (PRP) Injections: Significant debate persists regarding the true therapeutic value of autologous PRP. Proponents argue that growth factors (PDGF, TGF-beta, VEGF) released by concentrated platelets reverse hypocellularity and stimulate tenocyte proliferation in degenerative clefts. Conversely, critics cite heterogeneity in preparation protocols (leukocyte-rich vs. leukocyte-poor), activation methods, and equivocal results in double-blind sham-controlled randomized trials, suggesting that clinical improvements may reflect natural history and concurrent loading protocols.
• Open vs. Endoscopic / Arthroscopic Surgical Debridement: Advocates of open surgery emphasize that direct visualization ensures thorough excision of diseased deep tendon tissue and precise decortication of the sclerotic superior patellar pole, with the option to place suture anchors if needed. Champions of endoscopic debridement argue that avoiding an extensive skin incision and rectus splitting preserves the anterior extensor retinaculum, significantly lowers wound complication rates, reduces postoperative pain, and accelerates return to competitive sports.

13. Evidence-Based Synthesis

Modern clinical decision-making is grounded in high-quality randomized controlled trials and prospective registry analyses, corroborated by seminal biomechanical and anatomical descriptions.

14. References

• Rio E, Kidgell D, Purdam C et al. Isometric exercise induces analgesia and reduces inhibition in patellar tendinopathy. Br J Sports Med. 2015. doi:10.1136/bjsports-2014-094386 [Level I: Randomized Controlled Trial]
• Lopes HS, Waiteman MC, Priore LB et al. There is more to the knee joint than just the quadriceps: A systematic review with meta-analysis and evidence gap map of hamstring strength, flexibility, and morphology in individuals with gradual-onset knee disorders. J Sport Health Sci. 2024. doi:10.1016/j.jshs.2023.08.004 [Level I: Systematic Review / Meta-Analysis]
• Sprague AL, Smith AH, Knox P et al. Modifiable risk factors for patellar tendinopathy in athletes: a systematic review and meta-analysis. Br J Sports Med. 2018. doi:10.1136/bjsports-2017-099000 [Level I: Systematic Review / Meta-Analysis]
• Pekka Kannus, László Józsa. Histopathological changes preceding spontaneous rupture of a tendon. A controlled study of 891 patients. Journal of Bone and Joint Surgery. 1991. doi:10.2106/00004623-199173100-00009 [Level IV (Prognostic / Case Series): Seminal Conceptual / Observational Study]
• Susan Carolyn Slade, Clermont E. Dionne, Martin R Underwood et al. Consensus on Exercise Reporting Template (CERT): Explanation and Elaboration Statement. British Journal of Sports Medicine. 2016. doi:10.1136/bjsports-2016-096651 [Level IV (Prognostic / Case Series): Seminal Conceptual / Observational Study]

15. Master Class Pro-Tip

When approaching recalcitrant quadriceps tendinopathy surgically, the most common beginner error is failing to recognize that the true pathology is almost invariably confined to the deepest layer—the vastus intermedius footprint—and the adjacent superior patellar rim. Do not perform an unguided transverse wedge resection of the superficial tendon. Instead, make a meticulous 4 cm midline longitudinal split through the rectus femoris fibers directly over the superior patellar pole. Carefully retract the superficial and intermediate laminae with fine right-angle retractors to expose the deep vastus intermedius insertion. Here, you will encounter the characteristic grayish-yellow, mucinous, friable degenerate tissue. Excised this focal cleft cleanly with a #15 blade, taking care not to penetrate the underlying suprapatellar synovial pouch. Once debrided, examine the superior osseous margin: resect any prominent enthesophyte with a micro-rongeur and use a 1.5 mm K-wire to perform 3 to 4 gentle micro-perforations through the sclerotic bone bed into cancellous marrow, providing a rich biologic egress of marrow elements. Repair the longitudinal tenotomy with interrupted 2-0 Vicryl, maintaining an entirely intact superficial extensor apparatus. Postoperatively, discard rigid casting: initiate immediate passive motion from 0° to 60° and begin progressive isometric quadriceps setting on day one.

Master Class Surgical Pearl: Deep Lamina Debridement and Enthesis Micro-Perforation