Complete surgical technique guide for Primary Quadriceps Tendon Repair using suture anchors - FRCS Orth exam preparation with anatomy, Krackow suture technique, rehabilitation protocol, and viva scenarios
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Orthopaedic clinicians and medical editors • Published by OrthoVellum Medical Education Team
Suture anchor technique | Sports/Knee Surgery
Infrapatellar branch of saphenous. Location: Crosses anterior knee medially, can be injured with medial retraction. Injury = numb patch anterior knee (common, usually well-tolerated)
Arterial branches within tendon. Location: 2-4cm proximal to patellar insertion, within tendon substance. Careful dissection, bipolar cautery. Bleeding obscures field
Articular surface deep to tendon. Location: Visible when knee flexed. Risk with anchor placement too posterior or trans-osseous tunnel exit. Anchor 5mm from articular margin
Critical for patellar tracking. Location: Medial patella border, oblique fibers. Must repair VMO insertion - failure causes lateral tracking and recurrent instability
Absolute Indications
Relative Indications
Timing
Positioning
Implants
Instruments
Supplies
Patient Position: Supine with bump under ipsilateral hip for neutral leg rotation. Tourniquet on upper thigh (inflate to 250-300mmHg). Ensure knee can flex freely to at least 90 degrees - test before draping as this is essential for repair tensioning.
Anaesthesia: General or spinal. Femoral nerve block provides good postoperative analgesia but delays quadriceps assessment.
Surgical Approach: Anterior midline longitudinal approach over quadriceps tendon and superior patella
Surface Landmarks:
Midline longitudinal incision from 6-8cm proximal to superior pole of patella, extending to mid-patella (total 10-12cm). Incise through skin and subcutaneous tissue. Identify the rupture site - usually obvious with visible gap and hematoma. May need to extend proximally for chronic tears with retracted tendon.
Key Anatomy: Most ruptures occur 1-2cm proximal to patellar insertion (watershed zone of hypovascularity). 30% are bony avulsions at insertion. Ruptures typically initiate medially at VMO insertion (weakest point) and propagate laterally.
Exam Pearl
EXAM KEY: Midline incision gives best exposure and minimizes nerve injury. For chronic ruptures (greater than 6 weeks), extend proximally to mobilize retracted quadriceps. Identify torn retinacular edges which guide you to the injury.
Evacuate hematoma with suction and copious irrigation. Systematically assess rupture pattern:
Gently retract patella distally with Langenbeck retractor to visualize proximal tendon edge.
Exam Pearl
EXAM KEY: Complete rupture = discontinuity of ALL three quadriceps layers. Assess EACH LAYER independently. Partial tears often have intact intermediate layer (VMO/VL) maintaining some continuity and ability to SLR weakly. Chronic tears (greater than 6 weeks) have retraction, scarring, tissue degeneration - these need different approach.
Identify proximal tendon stump - may be retracted significantly in chronic tears. Use Allis clamps to grasp tendon for traction. Debride frayed degenerative edges minimally (1-2mm) to create perpendicular edge, but preserve tendon length. Assess tendon excursion by pulling distally with knee at 30-40 degrees.
Tendon Quality Assessment: Healthy tendon is white/pink, glistening, firm. Degenerative tendon is grey, friable, won't hold sutures (needs aggressive debridement or augmentation). Mark tendon layers with marking sutures to maintain orientation.
Exam Pearl
EXAM KEY: Tendon QUALITY is critical predictor of success. Grey, friable tissue won't hold sutures - needs aggressive debridement or augmentation. For acute tears, minimal debridement. Test excursion by pulling tendon distally with knee at 30-40 degrees flexion - if excessive tension (can't approximate without force), may need proximal release or augmentation.
Use rongeur or curette to remove fibrous tissue and create bleeding bone surface on superior pole of patella (insertion site). Create flat 1-1.5cm width footprint from anterior to posterior cortex. Expose cortical bone but don't penetrate or weaken patella excessively.
Technical Goals: Optimize biology for tendon-to-bone healing. Debride to 'bleeding bone' - punctate bleeding indicates healthy cortex. Mark proposed anchor positions before drilling.
Exam Pearl
EXAM KEY: Goal is optimal tendon-to-bone healing environment. Remove ALL cartilage and fibrous tissue (impedes healing). Roughening with burr increases surface area. Avoid excessive bone removal (weakens patella, fracture risk). Create rectangular footprint matching tendon width.
Insert 3-4 suture anchors (5.5mm or 6.5mm) into superior pole of patella:
Anchor Selection: Knotless anchors (SwiveLock, PushLock) provide stronger fixation. Three anchors minimum for standard tear, four for large/chronic tears.
Exam Pearl
EXAM KEY: Suture anchors are modern GOLD STANDARD - faster, biomechanically equivalent to trans-osseous tunnels, LESS patellar fracture risk (less than 2% vs 5-10% with tunnels). Position anchors 5mm from articular surface. Use knotless anchors if available - eliminates knot prominence and provides stronger fixation.
Pass anchor sutures through proximal tendon using locked KRACKOW technique:
Alternative: Mason-Allen horizontal mattress pattern with locking loop.
Exam Pearl
EXAM KEY: Krackow (locked whipstitch) provides STRONGEST fixation - 4-6 points of fixation per suture with locking mechanism preventing pullout. Failure load approximately 300N. CRITICAL: engage ALL THREE layers, not just superficial rectus. Use heavy sutures (#2 minimum, #5 ideal).
CRITICAL: Position knee at 30-40 degrees flexion for tying.
Pull sutures to advance tendon to patellar insertion site. Tie knots sequentially:
Use surgeon's knots (2-1-1 pattern) with 6-8 throws. Tension so tendon is snugly opposed to bone without excessive compression (allows 1-2mm tendon compression).
Exam Pearl
EXAM KEY: Repair TENSION is the critical decision. Tie at 30-40 degrees flexion (position of maximum extensor force). If tied at 0 degrees, repair too loose at functional flexion. If tied at 90 degrees, too tight at extension. Goal: tendon snugly opposed throughout 0-90 degrees ROM. Test by passively flexing to 90 degrees after tying - should maintain approximation without gapping greater than 3mm.
Repair torn medial and lateral retinaculum with 2-0 braided absorbable suture (Vicryl) in interrupted figure-of-8 or simple pattern. Start at patellar insertion and work proximally. Ensure VMO insertion is secure.
Technique for Chronic Tears: May need to mobilize adhesions and advance retinacular tissue. Consider imbrication (vest-over-pants overlap) for additional strength.
Exam Pearl
EXAM KEY: Retinacular repair provides 30-40% additional strength to construct - ESSENTIAL, not optional. Most ruptures propagate through retinaculum. Repair BOTH medial and lateral sides. VMO insertion must be secure (critical for patellar tracking). For chronic tears with retraction, advance and imbricate tissue.
For high-risk patients consider augmentation:
Indications for Augmentation: Chronic rupture greater than 6 weeks, revision repair, poor tissue quality, high-risk patients (diabetes, CKD, steroids).
Exam Pearl
EXAM KEY: Augmentation indicated for: (1) Chronic rupture greater than 6 weeks with tissue degeneration, (2) Revision after failed primary, (3) High-risk patients, (4) Poor tissue quality intraoperatively, (5) Repair under high tension. Suture tape technique increases failure load by 40-60% in biomechanical studies.
Release tourniquet. Test repair:
Document maximum safe flexion angle achieved for postoperative physiotherapy.
Exam Pearl
EXAM KEY: This is the PROOF of adequate repair. Under anaesthesia: passively extend knee fully (tests for lag). Then flex smoothly to 90 degrees - should feel firm resistance throughout arc. Sudden loss of resistance or visible gapping = repair failure requiring revision. Document safe flexion range for PT protocol.
Achieve meticulous hemostasis with bipolar cautery. Close paratenon with 3-0 absorbable suture (provides smooth gliding surface). Consider 10Fr drain if concern for hematoma. Close subcutaneous layer with 2-0 absorbable suture. Skin closure with staples or 3-0 nylon.
Exam Pearl
EXAM KEY: Paratenon closure often forgotten but improves gliding and cosmesis. Drain optional but helpful for 24 hours to prevent hematoma (increases infection risk and adhesions). Meticulous hemostasis essential - inflate/deflate tourniquet to identify bleeders before closure.
Apply sterile dressing. Place knee in hinged brace or cylinder cast LOCKED in FULL EXTENSION (0 degrees). This is MANDATORY.
Postoperative Protocol:
Exam Pearl
EXAM KEY: Extension immobilization is MANDATORY - prevents load on repair during early healing. Options: hinged brace (preferred - allows wound checks) or cylinder cast (more secure). Continue locked extension for 4-6 weeks, then progressive ROM. NWB minimum 6 weeks. Expect 6-12 months for full recovery.
| Complication | Recognition | Prevention | Management |
|---|---|---|---|
| Re-rupture/repair failure (10-20%) | Sudden pain, loss of extension, palpable gap; often with fall or forced flexion in early postop period | Secure Krackow technique with heavy sutures; augmentation in high-risk; strict bracing compliance; protected rehabilitation; patient education | If acute (less than 4 weeks): immediate revision with augmentation, prolonged immobilization. If chronic: allograft reconstruction or V-Y quadricepsplasty |
| Extensor lag (15-30%) | Inability to fully actively extend knee; usually 5-10 degrees lag visible with heel-to-bed lift test | Appropriate repair tension (tie at 30-40 degrees); secure fixation all layers; early isometric exercises; aggressive strengthening after healing | PT strengthening usually improves over 6-12 months; lag less than 10 degrees often functionally acceptable; rarely needs revision |
| Knee stiffness/loss of flexion (20-40%) | Unable to achieve 120 degrees flexion; difficulty with stairs, squatting; visible limitation compared to contralateral | Balance protection with progressive mobilization; supervised ROM exercises; avoid over-tightening repair; patellar mobilization | PT with passive stretching, patellar mobilization; MUA if less than 4 months and severe (greater than 30 degrees loss); arthroscopic adhesiolysis if refractory |
| Quadriceps weakness (10-20% persistent) | Objective weakness on isokinetic testing; difficulty stairs, running; visible atrophy | Early isometric exercises; aggressive strengthening after 12 weeks; avoid prolonged immobilization | Progressive resistance training; eccentric strengthening; most recover 80-90% by 12-18 months; residual weakness common in older patients |
| Patellar fracture (less than 2% anchors, 5-10% tunnels) | Sudden pain over patella; palpable fracture; loss of construct stability; XR confirms | Suture anchors preferred (avoid tunnels); if tunnels, space greater than 7mm apart; avoid osteoporotic bone | Non-displaced: conservative with extended immobilization. Displaced: ORIF challenging given underlying repair |
| Infection (2-5%) | Wound erythema, warmth, drainage; fever; elevated WCC/CRP | Prophylactic antibiotics (cefazolin 2g); meticulous hemostasis; minimize operative time | Superficial: oral antibiotics, wound care. Deep: washout, debridement, preserve repair if possible; IV antibiotics 6 weeks |
| Patella baja (5-10%) | Limited flexion, anterior knee pain, difficulty kneeling; lateral XR Insall-Salvati less than 0.8 postop | Avoid over-tensioning repair; progressive ROM after 4-6 weeks; patellar mobilization exercises | Prevention critical; established baja difficult to correct; PT for ROM; rarely proximal patellar tendon lengthening |
| Heterotopic ossification (3-5%) | Palpable mass at repair site; limited ROM; visible calcification on XR | Atraumatic technique; minimize bone bed trauma; consider indomethacin 25mg TDS x 6 weeks in high-risk | Most asymptomatic; observe if mild; excision if mechanical block (delay until mature 12-18 months) |
Practice these scenarios to excel in your viva examination
"A 62-year-old diabetic man stumbles on a step and presents with knee swelling and inability to walk. He cannot straight leg raise. Describe your assessment and management."
"Describe the anatomy of the quadriceps tendon and explain how this relates to repair technique."
"Compare suture anchor fixation versus trans-osseous tunnel technique for quadriceps tendon repair. What are the advantages and disadvantages of each?"
High-Yield Exam Summary
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Konrath GA, Chen D, Lock T, et al. Outcomes following repair of quadriceps tendon ruptures. J Orthop Trauma. 1998;12(4):273-279.
Ramseier LE, Werner CM, Heinzelmann M. Quadriceps and patellar tendon rupture. Injury. 2006;37(6):516-519.
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