High Yield Overview

QUADRICEPS TENDON REPAIR

Transosseous repair through patellar tunnels with Krackow locking suture technique

Sports-KneeSubspecialty

8Key Steps

5Danger Zones

60-90minDuration

Critical Must-Knows

Quadriceps rupture: older patients (>40), patellar tendon rupture: younger patients (<40)
Transosseous repair is GOLD STANDARD - strongest fixation
Tension repair in FULL EXTENSION, must achieve 90° flexion without gapping
Augmentation for chronic ruptures (>2-3 weeks) or poor tissue quality

Examiner's Pearls

"
Compare QUADRICEPS vs PATELLAR tendon rupture demographics and risk factors
"
Describe TRANSOSSEOUS technique with 3 tunnels and Krackow suture
"
Know AUGMENTATION indications (chronic, revision, poor tissue)
"
Recognize risk factors: diabetes, CRF, steroids, fluoroquinolones

Mnemonic

QUADRICEPSQUADRICEPS - Risk Factors

Q - Q-angle abnormalities

U - Uremia (chronic renal failure)

A - Age >40 years

D - Diabetes mellitus

R - Rheumatoid arthritis / inflammatory conditions

I - Immunosuppression / steroids

C - Chronic tendinopathy

E - Eccentric overload

P - Previous injection

S - Systemic fluoroquinolones

Memory Hook:EXAM KEY: Quadriceps rupture is MORE COMMON in OLDER patients (>40) with medical comorbidities. Patellar tendon rupture is more common in YOUNGER, athletic patients (<40). This demographic difference is a classic exam question.

Mnemonic

REPAIRREPAIR - Surgical Steps

R - Retracted stump identification (may be 5-10cm proximal)

E - End debridement to healthy tissue

P - Patellar tunnels x3 (transosseous)

A - Anchor sutures with Krackow technique

I - Isometric tensioning in full extension

R - Retinacular repair (medial and lateral)

Memory Hook:EXAM KEY: Transosseous repair is the GOLD STANDARD for quadriceps tendon repair. Use heavy non-absorbable sutures (#2 or #5 Ethibond/FiberWire) with Krackow locking configuration through 3 bone tunnels.

Critical Danger Structures

Suprapatellar Pouch

Knee joint communication: enters surgical field with tendon retraction. Must be protected and closed watertight. Violation causes hemarthrosis and increases infection risk.

Infrapatellar Branch Saphenous Nerve

Crosses surgical field obliquely from medial to lateral, 3-5cm below joint line. At risk during lateral retinacular exposure. Injury causes anterior knee numbness.

Descending Genicular Artery

Branch of femoral artery, runs with saphenous nerve medially. At risk during medial retinacular exposure. Control with electrocautery before vessel retraction.

Patellar Articular Surface

Risk of drill penetration into articular cartilage when creating transosseous tunnels. Aim tunnels to exit at inferior pole - use fluoroscopy if needed.

Patella Itself

Risk of PATELLAR FRACTURE during tunnel drilling, especially in osteoporotic bone. Use 2.5-3mm drill, create 3 tunnels minimum 10mm apart. Avoid bicortical drilling on articular side.

Quadriceps vs Patellar Tendon Rupture - Key Demographics

Feature	Quadriceps Tendon Rupture	Patellar Tendon Rupture
Age	Older patients (>40 years)	Younger patients (<40 years)
Mechanism	Eccentric contraction, stumbling	Athletic activity, jumping
Risk Factors	DM, CRF, steroids, fluoroquinolones	Previous surgery, tendinopathy, PRP
Location	1-2cm proximal to patella	Inferior pole patella
Patella Position	PATELLA BAJA (low riding)	PATELLA ALTA (high riding)
Gap	Palpable above patella	Palpable below patella
Incidence	More common (3:1)	Less common
Bilateral	More common (especially CRF)	Less common

Exam Pearl

EXAM KEY: Remember - Quadriceps rupture = patella BAJA (patella drops DOWN when tendon above retracts). Patellar tendon rupture = patella ALTA (patella rides HIGH when tendon below ruptures). This radiographic finding is pathognomonic.

Positioning and Preparation

Patient Position: Supine on radiolucent table, small bump under knee for slight flexion (10-20°)

Tourniquet: Non-sterile thigh tourniquet, inflated to 300mmHg after exsanguination

Surgical Approach: Midline longitudinal incision from mid-thigh to tibial tubercle (15-20cm)

Setup Verification: Fluoroscopy available for tunnel placement confirmation if needed

Operative Technique

Step 1: Exposure and Tendon Identification

Make midline longitudinal incision from mid-thigh extending to tibial tubercle. Identify the retracted proximal tendon stump - may be 5-10cm proximal in complete ruptures due to muscle contraction. Evacuate the suprapatellar hemarthrosis. Assess medial and lateral retinacular tears which often accompany the tendon rupture.

Exam Pearl

Technical Tip: The tendon stump retracts significantly due to quadriceps muscle contraction. Extend your incision proximally if stump not immediately visible. The suprapatellar pouch will be full of blood clot - irrigate thoroughly.

Dangers at this step

Missing retracted tendon stump - extend incision proximally
Inadequate hemarthrosis evacuation - causes postoperative stiffness

Step 2: Tendon Stump Debridement

Debride frayed and necrotic tissue from tendon stump back to healthy, bleeding tendon. Assess tissue quality - poor quality with fatty infiltration suggests need for augmentation. Preserve as much length as possible. In chronic ruptures, stump may be contracted and require mobilization.

Exam Pearl

Technical Tip: Good quality tendon has visible longitudinal collagen fiber pattern. Poor quality appears yellow, friable, or fatty. If in doubt about tissue quality, plan for augmentation.

Dangers at this step

Over-debridement shortening tendon excessively
Under-debridement leaving necrotic tissue (weak repair)

Step 3: Patellar Surface Preparation

Decorticate the superior pole of patella with rongeur or burr to expose bleeding cancellous bone. This creates a healing surface for tendon-to-bone incorporation. Mark the positions for 3 transosseous tunnels - central, medial, and lateral - minimum 10mm apart.

Exam Pearl

Technical Tip: Decorticating the superior patella creates a bleeding bone bed that promotes tendon healing. Similar principle to rotator cuff footprint preparation.

Dangers at this step

Tunnels too close together risking patellar fracture
Articular surface penetration with drill

Step 4: Transosseous Tunnel Creation

Drill 3 longitudinal tunnels using 2.5-3mm drill from superior pole to mid-patella (NOT through articular surface). Use curette to create gentle curve in tunnels, directing exit to anterior/inferior patella. Pass looped suture retriever through each tunnel from inferior to superior.

Exam Pearl

Technical Tip: Use fluoroscopy if concerned about articular surface penetration. The drill should exit at the inferior pole of patella anteriorly, NOT through the joint surface.

Dangers at this step

Patellar fracture from tunnels (osteoporotic bone)
Articular cartilage damage from drill penetration

Step 5: Krackow Suture Placement

Place Krackow locking sutures in the quadriceps tendon stump using heavy non-absorbable suture (#2 or #5 FiberWire/Ethibond). The Krackow technique creates interlocking loops that grip the tendon and don't pull through. Use 3 sutures, one for each tunnel.

Exam Pearl

Technical Tip: The Krackow suture is the gold standard for tendon repair - the locking loops prevent the suture from pulling through the tendon under tension. Each passage should take a 5mm bite of tendon.

Dangers at this step

Sutures too superficial (will pull out)
Incomplete locking pattern (suture slides)

Step 6: Suture Passage and Tensioning

Pass suture limbs through patellar tunnels using the suture retrievers. Reduce the tendon stump down to the decorticated patella surface. With knee in FULL EXTENSION, sequentially tension and tie sutures over bone bridge at inferior patella. Confirm tendon-bone apposition.

Exam Pearl

Technical Tip: CRITICAL - Tie sutures with knee in FULL EXTENSION. Test that knee achieves 90° passive flexion without repair gapping. If repair gaps at 90°, it is too tight and will cause extensor lag.

Dangers at this step

Over-tensioning causing stiffness (patella baja)
Under-tensioning causing extensor lag

Step 7: Retinacular Repair

Palpate and repair medial and lateral retinacular tears with interrupted sutures. These tears contribute to extensor mechanism dysfunction and should not be ignored. Repair in layered fashion - synovium/capsule, then retinaculum.

Exam Pearl

Technical Tip: Retinacular tears are often missed! Palpate systematically along both sides of the patella. Unrepaired retinacular defects cause ongoing weakness even with intact tendon repair.

Dangers at this step

Missing retinacular tears (persistent weakness)
Damage to infrapatellar nerve branch during lateral repair

Step 8: Intraoperative Assessment and Closure

Test active straight leg raise to confirm repair integrity. Verify passive ROM achieves 90° flexion. Close suprapatellar pouch watertight if violated. Irrigate wound and close in layers over drain. Apply hinged knee brace locked in extension.

Exam Pearl

Technical Tip: If patient cannot perform straight leg raise intraoperatively, the repair is inadequate. Consider augmentation or revision of fixation before closing.

Dangers at this step

Closing with inadequate repair (patient will fail)
Not testing extension - missing failed repair

Complications

Complications - Recognition, Prevention & Management

Complication	Recognition	Prevention	Management

Post-operative Care

Phase 1 (Weeks 0-2): Hinged knee brace LOCKED IN EXTENSION for weight bearing and sleep. Passive ROM 0-30° flexion only. Quadriceps isometrics and SLR in brace. Full weight bearing in locked brace.

Phase 2 (Weeks 2-6): Progressive passive ROM - increase 10-15° per week targeting 90° by week 6. Continue brace for weight bearing. Active assisted ROM exercises.

Phase 3 (Weeks 6-12): Unlock brace for ambulation once achieving 90° flexion. Begin active extension exercises. Progress strengthening. Wean from brace by week 8-10.

Phase 4 (Months 3-6): Full ROM exercises. Progressive resistance training. Return to activities at 4-6 months depending on strength recovery (>80% of contralateral side).

Exam Viva Scenarios

Practice these scenarios to excel in your viva examination

VIVA SCENARIOStandard

EXAMINER

"A 55-year-old diabetic male presents after stumbling down stairs. He has a palpable defect above the patella and cannot perform a straight leg raise. X-ray shows patella baja. How would you manage this patient?"

EXCEPTIONAL ANSWER

This is a clinical presentation of complete quadriceps tendon rupture. Key findings are: age >40 with diabetes (risk factors), eccentric injury mechanism, suprapatellar gap, loss of active extension, and patella baja on X-ray. I would confirm the diagnosis with clinical examination (palpable gap, hemarthrosis) and proceed with surgical repair. MRI is not mandatory if clinical diagnosis is clear. Surgery should ideally be performed within 2 weeks for best outcomes. I would perform transosseous repair using Krackow suture technique through 3 patellar tunnels, tension the repair in full extension confirming 90° flexion is achievable, and repair any retinacular tears. Given his diabetes, I would counsel him about increased infection and re-rupture risk.

KEY POINTS TO SCORE

Patella baja is pathognomonic for quadriceps tendon rupture (vs patella alta for patellar tendon)

Diabetes is a major risk factor for quadriceps rupture - also CRF, steroids, fluoroquinolones

Transosseous repair is gold standard - 3 tunnels, Krackow suture, tie in full extension

Surgery within 2 weeks for acute ruptures gives best outcomes

Must test 90° passive flexion achievable without repair gapping

COMMON TRAPS

✗Don't confuse with patellar tendon rupture (younger patients, patella alta)

✗Don't order MRI routinely - clinical diagnosis is usually sufficient

✗Don't forget to repair retinacular tears

✗Don't over-tension repair - causes stiffness

LIKELY FOLLOW-UPS

"When would you augment the repair? What augmentation technique would you use?"

VIVA SCENARIOStandard

EXAMINER

"You are repairing a quadriceps tendon rupture and the tissue quality appears poor with fatty infiltration. The rupture occurred 4 weeks ago. What are your concerns and how would you modify your approach?"

EXCEPTIONAL ANSWER

This is a chronic quadriceps rupture with poor tissue quality - both are indications for augmentation. My concerns are: (1) poor tissue may not hold sutures leading to repair failure, (2) tendon is likely contracted requiring mobilization, (3) higher re-rupture rate without augmentation. I would modify my approach by: (1) extending exposure proximally to mobilize contracted muscle, (2) aggressive debridement to healthy tissue, (3) augmenting the repair with autograft. My preferred augmentation is semitendinosus autograft harvested through a separate anteromedial incision, woven in figure-8 fashion through patellar tunnels and sutured to the native tendon. Alternative is synthetic tape augmentation (FiberTape) which provides load-sharing.

KEY POINTS TO SCORE

Chronic ruptures (>2-3 weeks) require augmentation

Poor tissue quality (fatty, friable) requires augmentation

Semitendinosus autograft is most common biological augmentation

Synthetic tape provides immediate load-sharing

Tendon mobilization may be needed to regain length

COMMON TRAPS

✗Don't attempt primary repair alone in chronic ruptures - high failure rate

✗Don't ignore tissue quality assessment

✗Don't forget to mobilize contracted proximal stump

✗Wire cerclage is historical and outdated - avoid mentioning as first-line

LIKELY FOLLOW-UPS

"What is the expected recovery timeline with augmented repair? What are the risks of semitendinosus harvest?"

VIVA SCENARIOStandard

EXAMINER

"While drilling your second transosseous tunnel in the patella, you feel the drill break through and see fluid egress from the joint. What has happened and how would you manage this?"

EXCEPTIONAL ANSWER

The drill has penetrated the articular surface of the patella - this is a recognized complication of transosseous tunnel creation. Immediate management: stop drilling, irrigate the joint to remove debris, and assess the damage. I would abandon that tunnel and create a new tunnel in a different position, angling it more anteriorly to exit at the inferior patella rather than the joint surface. If significant cartilage damage has occurred, I would document it and counsel the patient about potential long-term patellofemoral arthritis. To prevent this complication: use fluoroscopy for tunnel placement guidance, create tunnels with gentle curve using curette after initial drill pilot hole, and aim for inferior pole exit point. Alternative approach if bone quality is poor and multiple tunnel failures occur is to use suture anchors instead.

KEY POINTS TO SCORE

Articular penetration is a recognized complication of transosseous technique

Tunnel should exit at inferior pole anteriorly, not through joint surface

Fluoroscopy can guide tunnel placement if anatomy unclear

Use curette to redirect tunnel if initial trajectory is incorrect

Suture anchors are acceptable alternative if tunnel complications occur

COMMON TRAPS

✗Don't try to use the damaged tunnel - creates weak point

✗Don't ignore the articular damage - document and counsel patient

✗Don't continue without modifying technique - high risk of repeat penetration

✗Don't panic - this is manageable and repair can still be successful

LIKELY FOLLOW-UPS

"How would you approach repair in a patient with severely osteoporotic bone? Would you consider suture anchors in this situation?"