Elbow Fractures — Distal Humerus, Olecranon, Radial Head, Coronoid, Elbow Dislocation

Introduction

The elbow joint, with its unique configuration as a coupled hinge-and-pivot articulation involving three bones (distal humerus, proximal ulna, proximal radius) and three articulations (humeroulnar, humeroradial, proximal radioulnar) within a single capsule, presents a distinctive challenge in fracture management. The articular surface area is small but functionally critical; the constraint to motion provided by the bony anatomy is substantial but easily disturbed; and the soft-tissue envelope is thin, with the ulnar nerve, the brachial artery, the median nerve, and the posterior interosseous nerve all in close proximity to the joint. Loss of motion is the rule rather than the exception after elbow injury, and the orthopedic principle of early protected motion has been central to elbow trauma management since the time of John Charnley’s emphasis on it in the 1950s. The “Weber tension-band” technique for olecranon fractures, and the “terrible triad” of elbow dislocation with radial head and coronoid fracture, are among the named entities particularly emphasized in board examination preparation. This chapter draws principally on Rockwood and Green’s Fractures in Adults, AO Principles of Fracture Management, Apley & Solomon’s, and Miller’s Review of Orthopaedics.

Surgical Anatomy

The distal humerus comprises two diverging columns — the medial column terminating in the medial epicondyle and trochlea, and the lateral column terminating in the lateral epicondyle and capitellum — connected distally by the trochlea (the spool-shaped articulation with the ulna) and the capitellum (the rounded articulation with the radial head). The columns form an approximately 40-degree angle when viewed from the lateral aspect, with the articular surfaces translated anteriorly relative to the long axis of the humeral shaft. The olecranon fossa posteriorly and the coronoid fossa anteriorly accommodate the corresponding processes during full elbow flexion and extension. The carrying angle of the elbow — typically 5 to 15 degrees of valgus in the extended forearm — must be restored during reconstruction. The proximal ulna consists of the olecranon posteriorly and the coronoid process anteriorly, together forming the deep semilunar trochlear notch that articulates with the trochlea of the humerus. The olecranon is the principal insertion of the triceps tendon and the dominant component of the proximal ulna. The coronoid process is the principal anterior buttress against posterior subluxation of the ulna on the humerus; its disruption converts the elbow from a constrained hinge into an unstable joint. The radial notch of the ulna articulates laterally with the radial head, forming the proximal radioulnar joint stabilized by the annular ligament. The proximal radius consists of the radial head and the radial neck. The radial head is a disc-shaped articulation that contacts the capitellum and the radial notch of the ulna; the head also serves as a secondary stabilizer of the elbow to valgus stress (with the medial

collateral ligament being primary). The radial neck narrows below the head and meets the radial tuberosity, the insertion of the biceps tendon. The medial collateral ligament (MCL) complex has anterior, posterior, and transverse bundles. The anterior bundle is the primary restraint to valgus stress in mid-range elbow flexion and is the structure injured in throwing athletes (Tommy John surgery candidates). The lateral collateral ligament (LCL) complex includes the lateral ulnar collateral ligament (LUCL) — the primary restraint to posterolateral rotatory instability — the radial collateral ligament, the annular ligament, and the accessory lateral collateral ligament. The LUCL was first described by O’Driscoll, Bell, and Morrey in 1991 and recognition of its central role in posterolateral rotatory instability has transformed the management of complex elbow injuries. The ulnar nerve runs posterior to the medial epicondyle in the cubital tunnel, the most common site of compression neuropathy in the upper limb. The median nerve and brachial artery run anteriorly in the cubital fossa. The radial nerve passes anteriorly across the lateral aspect of the elbow, dividing into superficial sensory and deep motor (posterior interosseous nerve) branches; the posterior interosseous nerve is particularly vulnerable around the radial head and during exposures of the proximal radius.

Distal Humerus Fractures — Classification and Approach

The AO/OTA classification (region 13) for distal humerus fractures is the predominant system. Type A is extra-articular: A1 epicondyle (medial or lateral), A2 simple supracondylar, A3 multifragmentary supracondylar. Type B is partial articular: B1 lateral sagittal, B2 medial sagittal (median), B3 frontal/coronal (capitellar). Type C is complete articular (bicolumnar): C1 simple intra-articular and supracondylar, C2 simple articular with multifragmentary supracondylar, C3 multifragmentary articular and supracondylar. The historic Riseborough and Radin classification of intercondylar T- or Y-fractures (types I–IV by displacement and rotation) is largely superseded by the AO/OTA system but remains in clinical use. The distal humerus fractures of the elderly osteoporotic population have become increasingly common and present the central management dilemma in this region: the choice between open reduction and internal fixation (ORIF) with dual plate fixation versus primary total elbow arthroplasty (TEA). The trade-off in the elderly patient is the better functional outcome and lower revision risk of TEA against the lifelong restrictions (typically 5 kg or 10 lb single-event lifting limit) that protect the implant.

Treatment of Distal Humerus Fractures

ORIF with Dual Plating For the operative distal humerus fracture in the patient with reasonable bone quality, dual plate fixation has become the standard. The fundamental principle, articulated by O’Driscoll, is that each column must be supported by a plate, and the two plates should be applied so as to maximize compression and stability across the articular surface and supracondylar region. The two orientations most commonly used are perpendicular

plating (one plate on the posterolateral column, one on the medial column oriented at 90 degrees) and parallel plating (both plates on the medial and lateral columns oriented sagittally). Biomechanical evidence has favored parallel plating in some studies, particularly for restoring articular surface stability, although both approaches achieve good clinical results in experienced hands. The surgical approach is typically the olecranon osteotomy (chevron-shaped osteotomy of the olecranon to expose the articular surface, fixed with tension-band or screw at closure), which provides excellent exposure of the articular surface. The paratricipital approach (Bryan-Morrey or Alonso-Llames) preserves the olecranon and the triceps insertion but provides more limited articular visualization; it is preferred when the planned procedure is TEA, which avoids the morbidity of the osteotomy. The triceps- splitting (Campbell) and triceps-reflecting (Bryan-Morrey) approaches are alternative paratricipital options. Ulnar nerve management during distal humerus surgery is a long-debated point. Many surgeons routinely transpose the ulnar nerve anteriorly during distal humerus ORIF to remove it from the operative field; others perform in situ neurolysis without transposition. Outcome differences are debated, with the principal concern being delayed-onset ulnar neuropathy after transposition or stiffness with kinking of the nerve over hardware. Total Elbow Arthroplasty Total elbow arthroplasty (TEA) has emerged as a reliable alternative to ORIF in the elderly patient with severely comminuted distal humerus fracture and poor bone stock. The McKee and the Mayo Clinic trials of the 2000s and 2010s demonstrated superior functional outcomes and lower revision rates with TEA compared to ORIF in the patient over 65 with C2 or C3 fracture patterns. The current indication for primary TEA is the elderly low-demand patient (over 65 to 70 years) with severe articular comminution or pre-existing inflammatory arthritis. The principal trade-off is the lifelong restriction in lifting and impact loading that protects the implant; the elderly low-demand patient typically accepts these restrictions easily. Total elbow hemiarthroplasty is an alternative for fractures involving the articular surface with preservation of the proximal ulna and radial head, with limited but encouraging long-term evidence. Non-Operative Management Non-operative management is reserved for non-displaced or minimally displaced fractures, and for the very elderly low-demand patient in whom the morbidity of surgery cannot be justified. The “bag of bones” technique, with brief immobilization followed by early motion accepting whatever deformity heals, has had a small revival in this population.

Olecranon Fractures

The classical Mayo classification (Morrey, 1995) divides olecranon fractures into three types by displacement and stability. Type I is undisplaced (type IA non-comminuted, IB comminuted), treated non-operatively in a sling with early gentle motion. Type II is displaced but stable (IIA non-comminuted, IIB comminuted), requiring operative fixation.

Type III is unstable (associated with fracture-dislocation), requiring operative fixation with attention to the associated injury. Operative Techniques for Olecranon Fracture Tension-band wiring (Weber technique) is the classical operative technique for transverse non-comminuted olecranon fractures. The principle, established by Pauwels and applied by Weber to the olecranon, is the conversion of tensile forces on the dorsal cortex of the olecranon (produced by triceps pull and elbow flexion) into compressive forces at the articular surface through a tension-band wire passed dorsal to the fracture and anchored distally. Two parallel K-wires are passed across the fracture from the olecranon tip into the anterior cortex of the ulna; a figure-of-eight tension-band wire is then passed through a transverse hole drilled distal to the fracture, around the K-wires, and tightened on each side. The construct creates a “dynamic compression” at the articular surface during elbow motion. Complications include hardware prominence (in 30 to 80 percent of patients, with frequent need for hardware removal), K-wire migration, and inadequate fixation in comminuted patterns. Plate fixation with a precontoured locking olecranon plate is preferred for comminuted olecranon fractures, fracture-dislocations, and proximal extensions that would compromise tension-band fixation. Modern plates are anatomically contoured to the proximal ulna with multiple locking screws into the proximal fragment. The complications include hardware prominence (similar to tension-band but generally less severe), and the plate is the standard of care in complex injuries. Intramedullary fixation with the more recent intramedullary olecranon nails has emerged as an option offering reduced hardware prominence; outcomes are reportedly comparable. Fragment excision and triceps advancement (Cabanela technique) is reserved for the very elderly patient with severely comminuted small proximal fragments that cannot be reconstructed; up to 50 percent of the olecranon can be excised with reasonable functional outcomes if the coronoid and articular trochlear notch are preserved.

Radial Head and Radial Neck Fractures

The Mason classification (1954) for radial head fractures is the most widely used: Type I is non-displaced or minimally displaced (<2 mm); Type II is displaced (>2 mm) but less than 30 percent of the head; Type III is severely comminuted or involving more than 30 percent of the head; Type IV (Johnston modification) is radial head fracture with elbow dislocation. The Hotchkiss modification redefined types around operative implications: type I non-operative; type II amenable to ORIF; type III not amenable to ORIF and requiring excision or arthroplasty.

Treatment of Radial Head Fractures Type I is managed non-operatively, with a brief sling immobilization (3 to 5 days) followed by early active motion. The clinical aspiration test — joint aspiration with intra-articular

lidocaine to relieve hemarthrosis-related pain and assess for mechanical block — was historically performed but is now used selectively. Type II is managed by ORIF with small fragment screws (the Herbert screw or modern headless compression screws like the Acutrak provide excellent fixation buried below the articular surface) in patients with mechanical block to forearm rotation or in younger active patients; in selected cases, particularly in older patients without mechanical block, non-operative management with early motion produces comparable outcomes. Type III (and selected type II not amenable to ORIF) is managed by radial head excision in the simple isolated injury without associated instability, or by radial head replacement (arthroplasty) when the radial head is essential for elbow or forearm stability (terrible triad, Essex-Lopresti injury, MCL- incompetent elbow). Radial head arthroplasty uses modular monoblock metal prostheses (titanium or chromium-cobalt) of various designs. Critical technical considerations include avoidance of overlengthening (a head prosthesis that is too long produces capitellar wear, lateral pain, and tracking issues — the surgeon assesses appropriate sizing relative to the medial coronoid surface and the lateral coronoid level) and appropriate sizing to match the original head’s diameter. Radial head excision as a standalone procedure is reserved for the isolated radial head fracture in the elderly patient without associated instability and without Essex-Lopresti pattern. The procedure has long-term concerns including valgus instability, ulnar-positive variance with wrist pain, and progressive elbow arthritis, but in carefully selected patients produces acceptable outcomes.

Coronoid Fractures

The coronoid is the principal anterior buttress of the trochlear notch and its fracture, particularly when associated with elbow dislocation, produces profound instability. The Regan-Morrey classification (1989) divides coronoid fractures into three types by amount of the coronoid involved: Type I is a tip avulsion (<2 mm); Type II is up to 50 percent of the coronoid; Type III is more than 50 percent of the coronoid. The O’Driscoll classification more accurately describes the fracture morphology and provides better operative guidance, dividing coronoid fractures into tip, anteromedial facet, and basal fractures, each with subtypes. The anteromedial facet fracture of O’Driscoll deserves particular emphasis: this small fragment of the medial coronoid is the site of the anterior bundle of the medial collateral ligament insertion and is the key restraint to varus posteromedial rotatory instability. Even small (2 to 5 mm) anteromedial facet fractures may require operative fixation to prevent chronic instability. Treatment of coronoid fractures depends on the size and location of the fragment and on the associated injuries. Type I (tip) fractures in stable elbows are non-operative; tip fractures associated with terrible triad (see below) require fixation. Anteromedial facet fractures generally require fixation. Larger basal fractures (Regan-Morrey III,

O’Driscoll basal) require fixation, typically through a medial or posteromedial approach with small screws, suture fixation, or buttress plate.

Elbow Dislocation and the Terrible Triad

Simple elbow dislocation is dislocation of the elbow without associated fracture, typically posterior or posterolateral. The mechanism is a fall onto the outstretched hand with the forearm supinated, producing sequential disruption from lateral to medial (the Horii circle described by O’Driscoll). The classical sequence begins with disruption of the lateral ulnar collateral ligament (LUCL), progressing to the anterior capsule, then the medial collateral ligament (MCL), and finally the posterior capsule. Reduction by traction- countertraction with the elbow flexed produces a satisfactory result in most cases; recurrent instability after simple dislocation is rare. The post-reduction protocol is brief sling immobilization (3 to 7 days) followed by early motion, with most patients regaining excellent function. The terrible triad of the elbow — described by Hotchkiss in 1996 — is the combination of elbow dislocation, radial head fracture, and coronoid fracture. The injury is unstable because the lateral stabilizers (LCL, radial head) and the anterior stabilizer (coronoid) are all compromised. Treatment requires reconstruction of all three components, typically through a lateral approach (Kocher or extensor digitorum communis-splitting): repair or replacement of the radial head, repair of the coronoid (with screws, suture lasso, or suture anchors as size and location dictate), and repair or reconstruction of the LCL. The MCL is typically repaired only if instability persists after the lateral reconstruction. The historical poor outcomes that gave the injury its name (an Erlich-Hotchkiss patient series in the 1990s) have been substantially improved by the systematic approach of fixing all three components, with reasonable contemporary outcomes (~75 percent good to excellent functional results).

Special Patterns

The Monteggia fracture-dislocation (proximal ulna fracture with radial head dislocation) is addressed in Topic Trauma-16 (forearm fractures) but deserves mention here as another elbow-related complex injury. The Essex-Lopresti injury (radial head fracture with rupture of the interosseous membrane and distal radioulnar joint disruption) requires preservation of radial length (radial head retention or arthroplasty rather than excision) and management of the DRUJ disruption. Capitellar fractures (AO/OTA 13-B3) and the related Hahn-Steinthal (capitellum) and Kocher-Lorenz (smaller cortical) patterns are addressed by anterior screw fixation, with the lateral approach providing the necessary exposure. The anteromedial coronoid fracture pattern discussed above produces varus posteromedial rotatory instability requiring focused medial-side reconstruction. The floating elbow (combined humeral and forearm fractures) discussed in Topic Trauma-14 again requires operative fixation of at least the humeral component to allow rehabilitation. The pediatric supracondylar humerus fracture is a separate major entity managed by the Gartland classification and is addressed in the pediatric trauma sections; the discussion here pertains to the adult elbow.

Summary and Take-Home Points

Elbow fractures present the orthopedic surgeon with the challenge of restoring a complex coupled articulation while preserving the early motion that is essential to functional recovery. The distal humerus fracture in the elderly osteoporotic patient is approached by dual plate fixation in patients with reasonable bone quality and by primary total elbow arthroplasty in the very elderly with severely comminuted articular patterns. The olecranon fracture is approached by the classical Weber tension-band wiring for transverse non-comminuted patterns and by plate fixation for comminuted or proximal patterns; the very elderly patient with severe comminution may benefit from fragment excision with triceps advancement. The radial head fracture is classified by the Mason system and treated by non-operative management for Mason I, by ORIF for amenable Mason II, by radial head replacement for Mason III with associated instability, and by excision only for the isolated Mason III without associated instability and not in younger active patients. The coronoid fracture, particularly the anteromedial facet of O’Driscoll, is a key driver of elbow stability and frequently requires operative fixation in the setting of associated injuries. The terrible triad of elbow dislocation, radial head fracture, and coronoid fracture is now managed by systematic lateral-approach reconstruction of all three components — radial head, coronoid, LCL — with much-improved outcomes compared with the historical descriptions that gave the injury its name. The simple elbow dislocation without associated fracture is managed by closed reduction followed by early motion. The orthopedic principle of early protected motion — which has informed elbow trauma management since Charnley — remains the central concept linking all of these injuries, with the surgeon’s task being to provide sufficient fixation that early motion can begin without compromising the reconstruction. The chapter that follows turns to the forearm, where the principles of anatomical restoration and rigid fixation to permit early motion continue to apply but with distinct anatomical and biomechanical considerations.