Supine | Ulnar Nerve Protection | Coronoid and MCL Access
The ulnar nerve is the critical structure. Identify it proximal to the cubital tunnel, behind the medial epicondyle. Decide early whether to leave in situ, decompress, or transpose anteriorly. Most Hotchkiss approaches for coronoid fixation require at least in-situ decompression; chronic MCL reconstruction or revision cases often need subcutaneous transposition.
The MABC nerve (medial antebrachial cutaneous) crosses the incision field in the subcutaneous plane. Injury causes painful neuroma and numbness over the medial forearm. Identify and protect it during superficial dissection - it is often the first structure encountered after skin incision.
The true internervous plane lies between the brachialis (musculocutaneous nerve) proximally and the pronator teres (median nerve) distally. The Hotchkiss over-the-top split exploits this interval while preserving the common flexor origin on the medial epicondyle, allowing excellent coronoid and anteromedial access without detaching the flexor mass.
The anteromedial coronoid facet is reached by splitting the flexor-pronator mass and retracting the ulnar head of pronator teres anteriorly. Elbow extension and forearm supination bring the coronoid into view. Protect the anterior ulnar recurrent artery and the medial collateral ligament fibres inserting on the sublime tubercle.
Terrible triad injuries (radial head fracture + coronoid fracture + elbow dislocation) almost always require combined medial and lateral approaches. The Hotchkiss medial approach addresses the coronoid and MCL while the Kocher or Kaplan lateral approach fixes the radial head and lateral collateral complex. Plan both exposures from the start.
When performing MCL reconstruction through this approach, the sublime tubercle footprint on the ulna must be accurately identified. The anterior bundle inserts 5-7 mm distal to the joint line on the sublime tubercle. Tunnel placement too proximal or distal alters isometry and leads to stiffness or recurrent instability.
At a Glance
The Hotchkiss medial over-the-top approach provides direct access to the coronoid process, anteromedial facet, and medial collateral ligament while preserving the common flexor origin. It is the workhorse medial exposure for coronoid fixation in terrible triad injuries, MCL reconstruction, and selected distal humerus fractures. The patient is positioned supine with the arm across the chest. The ulnar nerve is identified and protected or transposed in virtually every case. The internervous plane between brachialis (musculocutaneous) and pronator teres (median) allows safe deep dissection. The medial antebrachial cutaneous nerve must be protected in the subcutaneous plane. This approach does not provide access to the radial head or capitellum - a separate lateral (Kocher) approach is required for complete terrible triad reconstruction.
HOTCHKISSHOTCHKISS - Surgical Steps
Hook:HOTCHKISS - always identify the ulnar nerve first and protect the MABC!
ULNARULNAR NERVE - Management Choices
Hook:ULNAR nerve decisions determine outcome - document position every time!
DANGERDANGER STRUCTURES - Layer by Layer
Hook:DANGER structures must be named layer by layer in the viva!
Indications and Approach Selection
Primary Indications:
- Coronoid process fractures (especially anteromedial facet) in terrible triad injuries
- Isolated coronoid fractures with elbow instability
- Medial collateral ligament reconstruction (acute or chronic)
- Anteromedial coronoid facet fractures with varus posteromedial rotatory instability
- Selected medial column distal humerus fractures requiring direct medial access
- Revision surgery after failed coronoid fixation or MCL reconstruction
Why This Approach is Chosen: The coronoid is the critical anterior buttress preventing posterior elbow subluxation. The Hotchkiss over-the-top split provides direct visualisation of the entire coronoid and sublime tubercle while preserving the flexor-pronator origin, maintaining elbow stability and allowing strong repair. It is the preferred medial exposure when combined with a lateral approach for terrible triad reconstruction.
Contraindications:
- Active infection over the medial elbow
- Severe soft tissue compromise requiring alternative coverage
- Isolated radial head or lateral column pathology (use Kocher approach)
- Patient unable to tolerate supine positioning with arm across chest
Alternative Approaches:
- Kocher lateral approach: For radial head, capitellum, and lateral collateral ligament
- Posterior approach to elbow: For distal humerus or olecranon
- Anterior Henry approach: Rarely used for elbow joint access
- Medial epicondylar osteotomy: For extensive distal humerus exposure (rare)
Overview
Hotchkiss Medial Over-the-Top Approach provides direct access to the coronoid, anteromedial facet, and medial collateral ligament complex through a flexor-pronator split that preserves the common flexor origin on the medial epicondyle.
Key Characteristics:
- Supine position with arm across chest
- Ulnar nerve identification and protection mandatory
- True internervous plane between brachialis and pronator teres
- MABC nerve protection in subcutaneous plane
- Often combined with lateral approach for terrible triad
Why This Approach Matters:
- Coronoid fractures occur in up to 40% of elbow dislocations
- Anteromedial facet fractures cause varus posteromedial rotatory instability
- MCL reconstruction success depends on accurate footprint restoration
- Ulnar nerve complications are the most common source of patient dissatisfaction
Exam Relevance:
- High-yield approach for upper limb operative surgery station
- Ulnar nerve management decisions are classic viva questions
- Distinction from Kocher lateral approach frequently tested
Anatomy
Bony Anatomy: The medial epicondyle gives origin to the common flexor-pronator mass. The coronoid process forms the anterior buttress of the ulna. The sublime tubercle on the medial ulna is the insertion site of the anterior bundle of the MCL. The trochlea of the humerus articulates with the greater sigmoid notch of the ulna.
Muscular Layers: The common flexor origin (pronator teres, flexor carpi radialis, palmaris longus, flexor carpi ulnaris, flexor digitorum superficialis) arises from the medial epicondyle. The Hotchkiss split passes between the ulnar and humeral heads of pronator teres or between brachialis and the flexor mass, preserving the origin.
Neurovascular Anatomy:
- Location
- Cubital tunnel behind medial epicondyle
- Clinical Significance
- Most important - identify early, decide transposition
- Location
- Subcutaneous, crosses incision
- Clinical Significance
- Protect to avoid painful neuroma
- Location
- Runs with ulnar nerve
- Clinical Significance
- Ligate branches for exposure
- Location
- Anterior compartment, medial to brachial artery
- Clinical Significance
- Not directly at risk but identify if extending proximally
- Location
- Medial to biceps tendon
- Clinical Significance
- Protect during proximal extension
Ligamentous Anatomy: The medial collateral ligament has anterior, posterior, and transverse bundles. The anterior bundle is the primary restraint to valgus stress and inserts on the sublime tubercle. The posterior bundle forms the floor of the cubital tunnel.
Internervous Plane
Deep Internervous Plane:
- Between: Brachialis (musculocutaneous nerve) proximally/medially and pronator teres (median nerve) distally
- Clinical relevance: This interval allows access to the coronoid and medial elbow without denervating any muscle. The split is developed bluntly after identifying the ulnar nerve.
Superficial Dissection: No true internervous plane exists superficially. The skin incision crosses the MABC nerve territory. The fascia over the flexor-pronator mass is incised in line with the muscle split.
The Hotchkiss approach is often described as "over-the-top" because the split passes over the medial epicondyle while preserving the flexor origin attachment. The plane is developed by identifying the interval between the humeral head of pronator teres (median nerve) and the more proximal brachialis fibres (musculocutaneous nerve). Distally the plane continues between pronator teres and flexor carpi ulnaris if further exposure is required. The ulnar nerve is always identified first and protected or transposed before the deep split is completed.
Structures at Risk in Each Layer:
- Structure
- Medial antebrachial cutaneous nerve
- Protection Strategy
- Identify and protect or sacrifice with proximal stump buried
- Structure
- Cubital tunnel roof (Osborne's ligament)
- Protection Strategy
- Release carefully to avoid ulnar nerve injury
- Structure
- Ulnar nerve and recurrent artery
- Protection Strategy
- Identify proximal, sling, decide transposition before splitting
- Structure
- Anterior ulnar recurrent artery branches
- Protection Strategy
- Ligate small branches, preserve main vessel
- Structure
- MCL anterior bundle on sublime tubercle
- Protection Strategy
- Protect footprint during coronoid exposure
Positioning and Patient Setup
Position: Supine with Arm Across Chest
Pre-positioning Checklist:
- Confirm no cervical spine injury if trauma case
- Arm board or hand table positioned for access
- Tourniquet applied high on arm
- Radiolucent table or arm board for fluoroscopy
- C-arm positioned from opposite side or distal
Positioning Details:
- Supine position on radiolucent table
- Arm across chest supported on a padded bolster or Mayo stand
- Shoulder in slight external rotation
- Elbow flexed 90 degrees for initial exposure
- Forearm in neutral or pronation initially
- Tourniquet inflated after exsanguination
When the arm is across the chest, the ulnar nerve is under tension behind the medial epicondyle. Slight elbow flexion (30-45 degrees) during initial dissection reduces this tension. Document ulnar nerve position and tension before and after transposition.
Alternative Positioning:
- Lateral decubitus with arm supported on a padded bolster (allows combined medial and lateral access without repositioning)
- Prone position rarely used for this approach
Surface Anatomy and Landmarks
Key Bony Landmarks:
- Medial epicondyle - prominent medial prominence, origin of flexor-pronator mass
- Medial supracondylar ridge - palpable proximal extension
- Olecranon - posterior landmark for orientation
- Ulnar shaft - palpable distally along medial forearm
Key Soft Tissue Landmarks:
- Ulnar nerve - palpable or rollable behind medial epicondyle in cubital tunnel
- Common flexor origin - firm mass just distal to medial epicondyle
- Medial antebrachial cutaneous nerve - often palpable or visible through thin skin
Incision Planning:
- Curvilinear incision centred over medial epicondyle
- Proximal limb: 5cm along medial supracondylar ridge
- Distal limb: 6-8cm along ulnar border of forearm, slightly anterior
- Total length 12-15cm depending on required exposure
- Mark ulnar nerve course before incision
Surgical Technique
Patient Position Supine with arm across chest on padded bolster. Elbow flexed 90 degrees. Tourniquet high on arm. Mark medial epicondyle, ulnar nerve course, and planned incision before prepping.
Key Landmarks Palpate medial epicondyle and confirm ulnar nerve position behind it. Mark the sublime tubercle on the ulna (approximately 5-7cm distal to joint line on medial ulnar border). Plan curvilinear incision from 5cm proximal to 8cm distal to epicondyle.
Fluoroscopy Setup Confirm C-arm access from the opposite side of the table or from distal. Obtain true AP and lateral views of the elbow before incision. Ensure the arm can be extended and supinated intra-operatively for coronoid visualisation.
Surgical Imaging
Structures at Risk
THE most important structure at risk. Courses through the cubital tunnel behind the medial epicondyle. Injury causes claw hand, loss of ulnar sensation, and intrinsic weakness. Prevention: identify proximal to epicondyle, decide transposition early, protect with vessel loop, avoid prolonged retraction, document position at closure.
Multiple branches cross the subcutaneous plane. Injury produces painful neuroma and numbness over the medial forearm. Prevention: identify early, protect when possible, or divide proximally and bury stump in muscle to prevent neuroma formation.
Runs with the ulnar nerve. Branches cross the surgical field during deep dissection. Prevention: ligate small branches, preserve main vessel, achieve meticulous haemostasis before closure.
Anterior bundle inserts on sublime tubercle. Damage during coronoid exposure causes valgus instability. Prevention: protect footprint, avoid aggressive retraction on sublime tubercle, repair any iatrogenic injury.
Ulnar Nerve Injury Management:
- If nerve damaged intra-operatively: primary repair if clean transection, otherwise observe
- Post-operative deficit: document extent, EMG at 3-4 weeks, consider exploration if no recovery by 3 months
- Permanent deficit: consider tendon transfers (ECRB to EDC, FCR to intrinsics) or nerve grafting
Extensile Modifications
Proximal Extension:
- Extend along medial supracondylar ridge
- Develop plane between brachialis and triceps
- Allows access to distal humerus medial column
- Median nerve and brachial artery become visible
Distal Extension:
- Continue along ulnar border of forearm
- Interval between pronator teres and flexor carpi ulnaris
- Useful for combined ulnar nerve exploration in forearm
- Ulnar artery lies deep to flexor carpi ulnaris
Combined Medial and Lateral Approaches: For terrible triad injuries, perform the Hotchkiss medial approach first to fix the coronoid and address MCL, then use a separate Kocher lateral approach for radial head fixation and lateral collateral repair. Both can be done in the supine position with arm across chest without repositioning.
Medial Epicondylar Osteotomy Variant: Rarely required for extensive distal humerus exposure. Osteotomise the medial epicondyle with attached flexor origin, reflect anteriorly, and repair with screws or tension band at closure. Adds morbidity and is reserved for complex intra-articular distal humerus fractures.
Complications
Intra-operative Complications:
- Prevention
- Identify early, protect with sling, decide transposition
- Management
- Primary repair if transected, document, post-op EMG
- Prevention
- Protect or bury proximal stump
- Management
- Pain management, neuroma excision if symptomatic
- Prevention
- Protect sublime tubercle insertion
- Management
- Direct repair or reconstruction
- Prevention
- Ligate branches, meticulous haemostasis
- Management
- Bipolar coagulation, pressure
Post-operative Complications:
- Incidence
- 5-15%
- Prevention
- Careful handling, transposition when indicated
- Treatment
- Observation, transposition if progressive
- Incidence
- 20-40%
- Prevention
- Early ROM, hinged brace
- Treatment
- Physiotherapy, manipulation under anaesthesia
- Incidence
- 5-10%
- Prevention
- Indomethacin or radiation in high-risk cases
- Treatment
- Excision after maturation if limiting ROM
- Incidence
- 1-3%
- Prevention
- Prophylactic antibiotics, meticulous closure
- Treatment
- Irrigation and debridement, culture-directed antibiotics
- Incidence
- 5-10%
- Prevention
- Anatomic coronoid fixation, accurate MCL tunnels
- Treatment
- Revision reconstruction or hinged external fixator
Ulnar nerve complications occur in 5-15% of medial elbow approaches. Most are transient neurapraxia from retraction. Permanent motor deficit is rare (less than 3%) when the nerve is identified early and transposition performed when the nerve is under tension or scarred. Always document the final position of the ulnar nerve in the operative note.
Post-operative Care
Immediate Post-operative:
- Document ulnar nerve motor and sensory function in recovery
- Check for MABC distribution numbness
- Posterior splint or hinged elbow brace locked at 90 degrees
- Elevate limb, ice, analgesia
Rehabilitation Protocol:
- Weeks 0-2: Immobilisation in 90 degrees flexion, gentle hand and wrist exercises
- Weeks 2-6: Hinged brace, progressive flexion-extension arc, avoid valgus stress
- Weeks 6-12: Full active ROM, begin strengthening, discontinue brace
- 3-6 months: Return to sport or heavy labour after strength recovery
Ulnar Nerve Specific Monitoring:
- Serial clinical examination of intrinsic function and sensation
- If transposition performed, educate patient on avoiding direct pressure on anterior nerve
- EMG at 6-8 weeks if any concern about nerve recovery
Evidence Base
Posterior dislocation of the elbow with fractures of the radial head and coronoid
Anatomical Cadaver Study of the Hotchkiss Over-the-Top Approach for Exposing the Anteromedial Facet of the Ulnar Coronoid Process
Outcome of ulnar neurolysis during post-traumatic reconstruction of the elbow
Soft tissue attachments of the ulnar coronoid process. An anatomic study with radiographic correlation
MCQ Practice Points
Q: What is the most important structure at risk during the Hotchkiss medial approach and how do you manage it? A: The ulnar nerve. Identify it proximal to the cubital tunnel before any deep dissection. Decide whether to perform in-situ decompression or anterior subcutaneous transposition. Most acute coronoid cases allow in-situ management; revision or scarred nerves require transposition. Always document the final position.
Q: What is the internervous plane in the Hotchkiss over-the-top approach? A: Between brachialis (musculocutaneous nerve) proximally and pronator teres (median nerve) distally. The split preserves the common flexor origin on the medial epicondyle, providing access to the coronoid without detaching the flexor mass.
Q: What nerve is at risk in the subcutaneous plane and what is the consequence of injury? A: The medial antebrachial cutaneous nerve. Injury produces a painful neuroma and numbness over the medial forearm. Identify and protect during superficial dissection or divide proximally and bury the stump in muscle.
Q: When would you combine the Hotchkiss medial approach with a lateral approach? A: Terrible triad injuries (radial head fracture + coronoid fracture + elbow dislocation) require both approaches. The medial approach addresses the coronoid and MCL while the Kocher lateral approach fixes the radial head and lateral collateral ligament complex.
Q: How do you visualise the coronoid during the Hotchkiss approach? A: Extend the elbow and supinate the forearm after developing the flexor-pronator split. This brings the anteromedial coronoid facet into direct view while protecting the MCL insertion on the sublime tubercle.
Guidelines, Registries & Global Practice
The Hotchkiss medial approach is used worldwide for coronoid fixation and MCL reconstruction. Principles are consistent across FRCS, FRACS, EBOT, ABOS and other examination systems. CT or MRI is mandatory for surgical planning of coronoid fractures and elbow instability. Ulnar nerve management is a universal examination topic.
Side-by-side principles (where guidance converges):
- Position on medial elbow approaches
- CT or advanced imaging for all coronoid fractures; combined medial-lateral approaches for terrible triad; ulnar nerve identification mandatory
- Position on medial elbow approaches
- Early mobilisation protocols; ulnar nerve monitoring and documentation; anatomic MCL reconstruction for chronic instability
- Position on medial elbow approaches
- Anatomic coronoid reduction and MCL isometry as primary goals; transposition when nerve under tension
Registry / population evidence:
- Coronoid fractures occur in approximately 2-10% of elbow dislocations, with anteromedial facet fractures carrying the highest risk of chronic instability if untreated.
- MCL reconstruction success rates exceed 85% when anatomic tunnel placement and early motion protocols are followed.
- Ulnar neuropathy after medial elbow surgery ranges from 5-15%, predominantly transient.
Global practice variation: In high-resource centres, dedicated coronoid plates, suture-button devices, and hamstring autograft for MCL reconstruction are standard. In resource-limited settings, screw or suture lasso fixation for coronoid and local tendon autograft (palmaris or gracilis) remain effective. Ulnar nerve transposition technique (subcutaneous vs submuscular) varies by surgeon preference and patient factors.
Consent (globally applicable): discuss ulnar nerve injury (5-15%, mostly transient), MABC neuroma (less than 5%), stiffness (20-40%), heterotopic ossification (5-10%), recurrent instability (5-10%), and the need for combined lateral approach in terrible triad injuries.
For the Orthopaedic Operative Surgery station you must describe the Hotchkiss approach systematically: supine positioning with arm across chest, ulnar nerve identification and management decision, MABC protection, internervous plane between brachialis and pronator teres, coronoid exposure by elbow extension and supination, and layered closure with nerve position documentation.
Exam Viva Scenarios
Practise clinical reasoning and management decisions out loud
“A 32-year-old falls from a ladder onto an outstretched hand and sustains an elbow dislocation with radial head and coronoid fractures. CT confirms a large anteromedial coronoid fragment. How would you approach this?”
“During a Hotchkiss approach for chronic MCL reconstruction, the ulnar nerve is found to be scarred and tethered in the cubital tunnel. What is your management?”
“A 28-year-old athlete presents with chronic medial elbow pain and instability after a varus injury. CT shows an anteromedial coronoid facet fracture nonunion. How would you manage this?”