Introduction Overview also known as Kocher or posterolateral approach Indications management of pathologies of the radial head ORIF radial head replacement radial head excision lateral collateral ligament (LCL) reconstruction or repair management of coronoid fractures (limited access) Plane Intermuscular plane between anconeus (radial n.) extensor carpi ulnaris (posterior interosseous n.) Preparation Anesthesia general advantageous for immediate post-operative neurologic examination or intra-operative airway control in patients with difficult airway brachial plexus nerve blocks advantageous for post-operative pain control Position supine with upper extremity supported on a hand table or on patient's trunk lateral decubitus with arm supported over a bolster forearm pronated in both positions Tourniquet applied to arm sterile tourniquet greater elbow access with sterile tourniquet exsanguinate limb with Esmarch or elevation Approach Incision landmarks lateral humeral epicondyle radial head 2.5 cm distal to lateral epicondyle, head (or crepitus in fractured) palpable with pronation/supination olecranon incision make a ~5cm longitudinal or gently curved incision based off the lateral epicondyle and extending distally over the radial head approximately incision angle can be varied based on need to address associated pathology Superficial dissection incise deep fascia in line with incision identify plane between ECU and anconeus distally Deep dissection maintain arm in pronation to move PIN away from field split proximal fibers of supinator, staying on the posterior cortex of the radius away from PIN if LCL intact, stay 1 cm anterior to crista supinatoris to avoid damage in cases of elbow dislocation, LCL frequently not intact incise capsule longitudinally avoid dissecting distally or anteriorly (PIN) maintain dissection in mid radiocapitallar plane to avoid damaging LCL Extension proximal extend superficial dissection by dissecting down onto lateral supracondylar ridge avoid origin of LCL unless operation directed at its repair/reconstruction distal this approach should not be extended distally as this places the PIN at risk Dangers Posterior Interosseous nerve not in danger as long as dissection remains proximal to annular ligament release supinator along posterior radius border beyond annular ligament with forearm in full pronation retractors placed blindly anteromedially or with excessive retraction may lead to nerve injury Radial nerve not in danger as long as elbow joint is entered laterally and not anteriorly