Lateral (Kocher) approach — true internervous plane between anconeus (radial nerve) and ECU (PIN) · advanced
- Larsen classification guides surgical decision-making: Grade I–III is suitable for synovectomy (preserved joint space), Grade IV–V requires arthroplasty
- The Kocher approach utilises a TRUE internervous plane between anconeus (radial nerve main trunk) and ECU (posterior interosseous nerve)
- Posterior interosseous nerve (PIN) protection is critical — keep dissection within 4 cm of the radiocapitellar joint and pronate the forearm to carry the nerve away from the radial neck during excision
- Radial head excision must preserve 2–3 cm of proximal radius to prevent proximal migration and DRUJ instability
- Indications: persistent synovitis despite 6 months medical management, painful limited ROM, Larsen I–III disease, painful radial head involvement
- The PIN lies 4–6 cm distal to the radiocapitellar joint on the anterior radial neck — protect with a strict 4 cm distal dissection limit plus forearm pronation
- Lateral collateral ligament complex preservation is essential — LUCL injury causes posterolateral rotatory instability (PLRI)
- Early ROM at 48–72 hours is critical in RA — prolonged immobilisation causes permanent stiffness
When & Why
Indication. A rheumatoid elbow with persistent synovitis despite at least 6 months of optimal medical management (DMARDs and biologics), painful limited range of motion interfering with activities of daily living, and Larsen Grade I–III disease (preserved joint space) on radiographs. A painful radial head with erosions, cystic change or radiocapitellar impingement is the trigger for adding radial head excision. Surgery is offered once conservative care — including at least one intra-articular corticosteroid injection — has failed. Primary indications
- Persistent elbow synovitis despite 6 months optimal medical management (DMARDs, biologics)
- Painful limited range of motion interfering with ADLs
- Larsen Grade I–III disease (preserved joint space on radiographs)
- Painful radial head involvement with crepitus, erosions or cystic changes
- Radiocapitellar impingement causing mechanical symptoms
- Palpable synovial thickening with effusion Contraindications
- Larsen Grade IV–V disease (advanced joint destruction) — consider arthroplasty
- Active infection or recent septic arthritis
- Severe medical comorbidities precluding surgery
- Poor bone quality with fracture risk
- Combined MCL and radial head insufficiency (causes severe valgus instability)
- Unrealistic patient expectations (patient must understand recurrence risk)
- Joint status
- Soft-tissue swelling and/or erosions; joint space preserved
- Operation
- Synovectomy alone — preserve radial head if possible
- Joint status
- Joint-space narrowing, less than 50% loss
- Operation
- Synovectomy plus radial head excision if symptomatic
- Joint status
- Joint-space narrowing, greater than 50% loss
- Operation
- Total elbow or interposition arthroplasty
- Joint status
- Complete joint destruction or ankylosis
- Operation
- Total elbow arthroplasty
Preoperative assessment. Document ROM (normal flexion 0–150°, pronation/supination 80°/80°) and any flexion contracture, test valgus/varus stability, and examine the ulnar nerve (Tinel's, subluxation, motor and sensory function). Image with AP/lateral and oblique radiographs for Larsen grading and erosion assessment; MRI quantifies synovial hypertrophy and cartilage if needed, and CT assesses bone stock only if arthroplasty is contemplated. Optimise the patient with rheumatology: continue methotrexate (low infection risk), consider holding biologics 1–2 weeks perioperatively, continue physiologic steroids with stress-dose cover if indicated, and address the malnutrition common in RA. Expected outcomes to quote at consent. Pain relief in 70–80% at 5 years, improved ROM by 20–30 degrees on average, patient satisfaction 75–85%, but recurrent synovitis in 30–50% at 5–10 years. Synovectomy is a temporising procedure that typically buys 5–10 years before arthroplasty is needed. Consent specifically for recurrence of synovitis (temporising, not curative), PIN injury with finger/thumb extension weakness, elbow instability (PLRI from LUCL injury, valgus instability if MCL deficient), stiffness, wound problems and infection (higher than non-RA due to immunosuppression), and ulnar nerve symptoms. Setup. Supine with the arm across the chest on a bolster, upper-arm tourniquet at 250–300 mmHg after exsanguination, general or regional (interscalene or axillary block) anaesthesia.
The Operation
The goal: expose the radiocapitellar joint through the lateral (Kocher) interval, clear hypertrophic synovium from both the anterior and posterior compartments, excise a painful eroded radial head when indicated while protecting the PIN and the lateral collateral ligament complex, and regain motion — then splint for comfort only and mobilise early. The exposure is laid out as the first steps below, and in depth on the Kocher approach to the elbow page.
Operative sequence
- Supine with the arm across the chest on a bolster (best lateral-elbow exposure); lateral decubitus with arm support is an alternative.
- Upper-arm tourniquet at 250–300 mmHg after exsanguination; general or regional (interscalene or axillary block) anaesthesia.
- Palpate and mark the lateral epicondyle (most prominent lateral landmark), the radial head (2 cm distal, rotates with forearm rotation), and the olecranon tip. Plan the incision along the lateral-epicondyle-to-radial-head axis. Mark before prepping — the radial head is confirmed by feeling it rotate under the finger.
- 8–10 cm longitudinal incision from the lateral epicondyle distally, centred over the radial head; extend 3–4 cm proximal to the epicondyle and 5–6 cm distal as needed.
- Divide subcutaneous tissue in line with the skin.
- Identify the fascial interval between anconeus (posterior) and ECU (anterior).
- This is a true internervous plane: anconeus is supplied by the radial nerve main trunk, ECU by the posterior interosseous nerve (PIN). No motor nerve is crossed — the safest route to the lateral elbow.
- Divide the fascia sharply and develop the interval by blunt dissection (finger or Mayo scissors). Anconeus fibres run obliquely posteriorly; ECU fibres run longitudinally.
- Retract anconeus posteriorly and ECU anteriorly to expose the joint capsule and the lateral collateral ligament (LCL) complex.
- The LCL complex lies deep — identify and preserve it intact. Make the capsulotomy anterior to the LCL complex.
- The lateral ulnar collateral ligament (LUCL) — lateral epicondyle to the supinator crest of the ulna — is the primary restraint to posterolateral rotatory instability (PLRI); the radial collateral ligament blends with the annular ligament.
- The PIN lies anterior to the radial neck deep to ECU — keep retractors on bone and avoid blind anterior dissection.
- Longitudinal capsular incision anterior to the LCL complex, extended proximally and distally along the joint line.
- Preserve the LCL complex posteriorly.
- Remove hypertrophic, inflamed synovium with rongeurs, shavers and small curettes.
- Clear the anterior compartment thoroughly — capitellum, radial head and coronoid fossa; lift pannus off the articular surfaces.
- Incomplete synovectomy drives early recurrence (30–50% at 5 years) — be systematic.
- Access the posterior compartment by extending the capsulotomy posteromedially.
- Clear the olecranon fossa and posterior capsule of synovium and loose bodies.
- The ulnar nerve lies 2–3 cm posterior to the medial epicondyle in the cubital tunnel — identify and protect it during any medial extension.
- Inspect the radial head for erosions, cystic change and cartilage loss; palpate for crepitus with passive pronation/supination; assess the radiocapitellar articulation.
- Excise if painful with rotation, eroded or cystic, or causing radiocapitellar impingement or mechanical symptoms.
- Preserve if the cartilage is intact and pain-free — the radial head contributes valgus stability (secondary stabiliser, especially if the MCL is deficient) and transmits 30–50% of forearm axial load.
- Protect the PIN: keep all dissection within 4 cm of the radiocapitellar joint and pronate the forearm to carry the nerve away from the radial neck.
- Circumferentially expose the radial neck with strict subperiosteal dissection, staying on bone; divide the annular ligament under direct vision.
- Perform an oscillating-saw osteotomy of the radial neck 2–3 mm distal to the radiocapitellar joint (just below the articular surface). Remove the head specimen and smooth the edges with a rongeur.
- Do not resect distal to the annular ligament/bicipital tuberosity — excessively low excision risks proximal radial migration and DRUJ pain or instability.
- If a flexion contracture exceeds 30°, excise the thickened anterior capsule, clear coronoid-fossa adhesions and elevate brachialis off the anterior distal humerus.
- Anterior coronoid osteophytes block extension; posterior olecranon osteophytes block flexion — address both for full ROM. Intra-operative goal: less than 30° flexion contracture.
- Stay lateral and on bone — the median nerve and brachial artery lie medially in the antecubital fossa.
- For posterior synovitis or olecranon impingement, extend posteromedially between anconeus and FCU; develop carefully with the ulnar nerve in mind.
- Remove posterior synovium from the olecranon fossa; excise olecranon osteophytes that block flexion; remove loose bodies.
- If there are preoperative ulnar symptoms (numbness, weakness, subluxation), identify the nerve posterior to the medial epicondyle.
- Perform in-situ decompression: release Osborne's ligament, divide the arcade of Struthers proximally and the FCU fascia distally; neurolyse if there is perineural scarring.
- Reserve anterior transposition for severe symptoms, instability, or failed in-situ decompression — RA patients have a higher complication rate with transposition (thin soft tissue, poor healing).
- Release the tourniquet temporarily; passively assess ROM — flexion (goal 130–140°), extension (goal less than 30° flexion contracture), pronation/supination (goal 70°/70°).
- Test valgus (MCL), varus (LCL) and posterolateral rotatory stability (lateral pivot shift). Gentle manipulation only — osteopenic RA bone fractures easily.
- Release the tourniquet definitively; meticulous bipolar haemostasis (RA patients on aspirin, NSAIDs, warfarin, steroids, DMARDs and biologics bleed more).
- Irrigate and place a small drain (10 Fr round or 7 mm flat), exiting posteriorly away from the radial nerve; remove at 24–48 hours when output is less than 30 mL per 8 hours. Haematoma increases infection risk and stiffness.
- Attempt capsular closure if tissue allows (often too thin or deficient in RA); stability relies on the intact LCL complex.
- Close the ECU–anconeus interval with 2-0 Vicryl; subcutaneous layer 3-0 Vicryl; skin with interrupted 3-0 or 4-0 nylon vertical-mattress sutures (allow drainage) or subcuticular 4-0 Monocryl. Interrupted sutures are preferred in RA (easier to remove if wound issues, allows drainage).
- Apply a posterior splint at 90° flexion, neutral forearm rotation, for comfort only — not rigid immobilisation. Begin early ROM at 48–72 hours.
Before any radial head excision, commit to a strict 4 cm distal dissection limit from the radiocapitellar joint. Cadaveric data (Lawton, JSES 2007) place the PIN a mean 4.6 cm distal in supination and 5.7 cm in pronation, with a minimum of just 4.0 cm. Keep the dissection subperiosteal on bone, pronate the forearm as an adjunct, and divide the annular ligament under direct vision — never dissect blindly anterior to the radius. PIN injury (1–2%) presents as immediate loss of finger MCP and thumb IP extension with preserved wrist extension and intact sensation.
The single most reliable safeguard is distance: keep subperiosteal dissection within 4 cm of the radiocapitellar joint. Forearm pronation is a useful adjunct to carry the nerve away from the radial neck, but Lawton showed pronation does not reliably increase the nerve-to-joint distance, so position reinforces — it does not replace — the distance limit. Always stay subperiosteal on bone and divide the annular ligament under direct vision.
The Kocher interval is developed anterior to the LCL complex, and the capsule is incised anterior to the ligaments. The LUCL (lateral epicondyle to the supinator crest of the ulna) is the primary restraint to posterolateral rotatory instability — injuring it causes PLRI with apprehension, clunking and subluxation. Preserve the LUCL insertion; if it is damaged iatrogenically, repair it primarily or reconstruct it (palmaris or gracilis graft, docking or figure-8 technique).
Branches from the radial nerve near the radiocapitellar joint, dives through supinator at the arcade of Frohse and lies on the anterior radial neck a mean 4.6 cm distal in supination and 5.7 cm in pronation (minimum 4.0 cm). Protect with a strict 4 cm distal dissection limit (the most reliable safeguard), forearm pronation as an adjunct, subperiosteal dissection on bone, and dividing the annular ligament under direct vision.
Lies in the spiral groove on the posterolateral humerus 10–12 cm proximal to the lateral epicondyle, pierces the lateral intermuscular septum and travels anterior to the epicondyle between brachialis and brachioradialis. Stay distal to the epicondyle during the approach; if extending proximally, remain anterior to the intermuscular septum with gentle retraction only.
Lies 2–3 cm posterior to the medial epicondyle in the cubital tunnel between the medial epicondyle and olecranon, under Osborne's ligament, then between the two heads of FCU. The Kocher approach stays 3 cm from medial structures; if posterior access is needed, identify the nerve before capsulotomy and perform in-situ decompression if symptomatic.
Lie medial to the biceps tendon in the antecubital fossa, deep to lacertus fibrosus; the median nerve crosses anterior to brachialis then passes between the two heads of pronator teres. The lateral approach avoids them; during any anterior capsular release stay subperiosteal on bone with no blind medial retraction.
LUCL originates from the lateral epicondyle and courses posteroinferiorly to the supinator crest of the ulna; the RCL blends with the annular ligament that encircles the radial head. Develop the interval anterior to the LCL complex, incise the capsule anterior to the ligaments, preserve the LUCL insertion on the ulna, and repair if inadvertently damaged.
Aftercare & Complications
Rehabilitation | Phase | Timing | Priorities | |-------|--------|------------| | 1 | 0–2 weeks | Posterior splint at 90° for comfort only; drain removed at 24–48 hours; begin gentle active ROM at 48–72 hours (5–10 min every 1–2 hours) | | 2 | 2–6 weeks | Removable splint; active-assisted ROM; therapist supervision; aim for full active ROM by 3–4 weeks | | 3 | 6–8 weeks | Light resistance and progressive strengthening; scar mobilisation | | 4 | Return to function | Desk work around 6 weeks; coordinate with rheumatology to optimise medical management (biologics reduce recurrence) | Avoid prolonged immobilisation (more than 3–5 days causes permanent stiffness in RA), avoid passive stretching initially (increases inflammation), and monitor for recurrence (warmth, swelling, loss of motion). Patient education is essential: synovectomy is temporising, not curative — the disease continues.
- Recognition
- Gradual return of pain, swelling, warmth and stiffness with loss of ROM; synovial thickening on exam and progressive erosions or joint-space loss on radiograph
- Prevention
- Complete synovectomy of anterior AND posterior compartments; optimise medical management post-op (DMARDs, biologics); counsel that synovectomy is temporising
- Management
- Intensify medical management (biologics, DMARD adjustment); intra-articular steroid; revision synovectomy rarely indicated; progress to arthroplasty if Larsen IV–V develops
- Recognition
- Immediate post-op inability to extend fingers at MCP and thumb at IP (EPL, EPB, EIP, EDC, EDM paralysis) with preserved wrist extension (ECRL/ECRB spared) and intact sensation (pure motor); usually neuropraxia
- Prevention
- Keep dissection within 4 cm of the radiocapitellar joint (most reliable safeguard); pronate the forearm as an adjunct; strict subperiosteal dissection; divide the annular ligament under direct vision
- Management
- Neuropraxia: reassure, hand therapy, dynamic extension splint, recovery 3–6 months, EMG at 3–4 weeks and 3 months; neurotmesis: early exploration and grafting; tendon transfers if no recovery by 12 months
- Recognition
- Persistent limited ROM beyond 6–12 weeks; flexion less than 110°, extension deficit greater than 30°; passive ROM limited; radiographs may show heterotopic ossification
- Prevention
- Early active ROM at 48–72 hours; avoid prolonged immobilisation; formal therapy at 2 weeks; indomethacin 25 mg TID for 6 weeks if HO risk
- Management
- Intensify therapy, static-progressive then dynamic splinting, gentle passive stretching after 4–6 weeks; arthroscopic or open capsular release if persistent beyond 6 months; excise mature HO at 18–24 months
- Recognition
- Valgus instability (MCL insufficiency plus radial head loss); varus instability (LCL injury); PLRI with posterolateral apprehension, clunk or subluxation and positive pivot shift
- Prevention
- Preserve the LCL complex (especially LUCL); capsular incision anterior to the ligaments; preserve the radial head if MCL deficient; repair the LCL if iatrogenically injured
- Management
- Valgus instability: hinged brace, MCL reconstruction if symptomatic (palmaris, figure-8); PLRI: activity modification then LUCL reconstruction (palmaris, gracilis or allograft) if persistent
- Recognition
- Numbness and tingling in small and ring fingers, intrinsic weakness, positive Froment's sign, clawing if severe; EMG confirms
- Prevention
- Protect the ulnar nerve during posterior access; stay 3 cm from medial structures; prophylactic in-situ decompression if pre-op symptoms; pad the elbow post-op
- Management
- Mild: observation, activity modification, night extension splint; persistent or progressive: in-situ decompression or anterior transposition; intrinsic strengthening therapy
- Recognition
- Dehiscence, delayed healing or drainage beyond 2 weeks, skin necrosis, superficial infection (erythema, purulent drainage)
- Prevention
- Careful soft-tissue handling (thin skin in RA); avoid tension; interrupted sutures; drain 24–48 hours; optimise nutrition; hold methotrexate 1 week peri-op; continue low-dose steroids
- Management
- Local wound care and dressing changes; delayed closure or wound VAC; antibiotics and irrigation and debridement if infected, culture-directed
- Recognition
- Fever, increasing pain, erythema, warmth, purulent drainage; raised WBC, CRP, ESR; aspirate WBC greater than 50,000, positive culture (Staph aureus commonest)
- Prevention
- Meticulous hemostasis and drain; perioperative cefazolin; hold biologics 1–2 weeks pre-op; sterile technique; control diabetes
- Management
- Early (less than 3 weeks): irrigation and debridement, culture-directed IV antibiotics 6 weeks (vancomycin if MRSA); late: resection arthroplasty or fusion; chronic suppression if unfit for surgery
Viva & Exam Focus
LARSENLarsen RA grading system
Hook:Grades I–III are suitable for synovectomy (joint space preserved); Grades IV–V require arthroplasty or interposition. The classification guides surgical decision-making.
PROTECT PINPIN protection during radial head excision
Hook:A strict 4 cm distal dissection limit (Lawton, JSES 2007), reinforced by forearm pronation and subperiosteal technique, is the key to avoiding PIN injury during radial head excision.
Clinical Decision Scenarios
Practise clinical reasoning and management decisions out loud
“A 52-year-old woman with seropositive RA presents with persistent left elbow pain and stiffness despite 6 months of optimal medical management including methotrexate and etanercept. ROM is 30–120° (flexion contracture). Radiographs show Larsen Grade III changes with erosions but preserved joint space. She has failed cortisone injections. Describe your approach to Larsen classification and surgical decision-making.”
“During radial head excision via lateral Kocher approach, you are concerned about posterior interosseous nerve (PIN) injury. Describe the anatomy of the PIN, why it is at risk, and specific steps you take to protect it during radial head excision.”
“During synovectomy, you need to preserve the lateral collateral ligament complex. Describe the anatomy of the LCL complex, its function, what happens if it is injured, and how you protect it during the approach.”
Indications
- Persistent elbow synovitis despite 6 months optimal medical management (DMARDs, biologics)
- Painful limited ROM interfering with ADLs, flexion contracture
- Larsen Grade I–III disease (I equals soft tissue swelling only, II equals erosions with preserved space, III equals less than 50% space loss)
- Painful radial head with erosions, cystic changes, or radiocapitellar impingement
- Contraindications: Larsen IV–V (need arthroplasty), active infection, combined MCL and radial head insufficiency
Key anatomy
- Kocher approach: true internervous plane between anconeus (radial nerve) and ECU (PIN)
- PIN: branches 6 cm proximal to the joint, enters supinator at the arcade of Frohse, lies anterior to the radial neck 4–6 cm distal to the joint
- LCL complex: LUCL is most important (lateral epicondyle to supinator crest), prevents PLRI
- Ulnar nerve: 2–3 cm posterior to the medial epicondyle in the cubital tunnel under Osborne's ligament
- Radial nerve main trunk: 10–12 cm proximal to the lateral epicondyle in the spiral groove
Critical steps
- Position supine with arm across chest; mark the lateral epicondyle and the radial head (palpate with forearm rotation)
- 8–10 cm incision from lateral epicondyle to radial head; develop the Kocher interval (anconeus–ECU)
- Capsulotomy anterior to the LCL complex; complete synovectomy of anterior AND posterior compartments
- Radial head excision if painful or eroded: 4 cm distal dissection limit plus pronation (protect PIN), osteotomy 2–3 mm below the joint at the neck, do not resect below the bicipital tuberosity
- Anterior capsular release if flexion contracture greater than 30°; assess ROM and stability; meticulous hemostasis and drain
Danger zones
- PIN: 4–6 cm distal to the joint on the anterior radial neck — protect with a 4 cm distal dissection limit plus forearm pronation
- Radial nerve: 10–12 cm proximal in the spiral groove — stay distal to the epicondyle
- Ulnar nerve: 2–3 cm posterior to the medial epicondyle — stay lateral, protect if posterior access
- Median nerve and brachial artery: medial in the antecubital fossa — stay lateral and on bone
- LUCL: lateral epicondyle to supinator crest — preserve to prevent PLRI
Technique pearls
- 4 cm distal dissection limit equals the reliable PIN safeguard; forearm pronation is a useful adjunct (rotation alone is not fully protective — Lawton JSES 2007)
- Do not resect below the bicipital tuberosity after radial head excision (prevents proximal migration and DRUJ instability)
- Complete synovectomy of BOTH compartments (anterior and posterior) to reduce recurrence
- LCL preservation critical: capsulotomy anterior to the ligaments, preserve LUCL insertion
- Early ROM at 48–72 hours essential in RA (rapid stiffness if immobilised)
Complications
- Recurrent synovitis 30–50% at 5–10 years (disease progression, incomplete synovectomy) — optimise medical management
- PIN injury 1–2% (finger/thumb extension loss) — usually neuropraxia, recovers 3–6 months with splinting
- Stiffness 10–20% (inadequate rehab, HO) — early ROM, indomethacin prophylaxis for HO risk
- Instability 5–10%: PLRI from LUCL injury, valgus from radial head excision with MCL insufficiency
- Infection 2–5% (higher in RA on immunosuppression) — meticulous hemostasis, periop antibiotics
Post-op protocol
- Drain removal 24–48 hours (when output less than 30 mL per 8 hours)
- Splint at 90° flexion for comfort only — not rigid immobilisation
- Active ROM 48–72 hours (5–10 min every 1–2 hours), active-assisted at 1–2 weeks, strengthening at 6–8 weeks
- Coordinate with rheumatology to optimise medical management (biologics reduce recurrence)
- Monitor for recurrence: warmth, swelling, loss of ROM — may need intensified medical treatment
Exam tips
- Know Larsen: I–III for synovectomy (preserved space), IV–V for arthroplasty
- State 'keep dissection within 4 cm of the joint, pronate the forearm as an adjunct' to protect the PIN during radial head excision
- Emphasise Kocher is a true internervous plane (anconeus/radial versus ECU/PIN)
- LUCL prevents PLRI (not RCL) — injury causes posterolateral rotatory instability
- Synovectomy is temporising not curative — 30–50% recurrence, eventual arthroplasty in many
- RA patients have higher complications: infection (immunosuppression), wound issues (steroids, thin skin), stiffness (rapid onset)
Background & Evidence
Pathoanatomy and rationale. In the rheumatoid elbow, hypertrophic synovial pannus invades the joint, erodes cartilage and bone, and stretches the capsule and ligaments — producing the triad of pain, synovitis-driven stiffness and progressive erosive destruction. Synovectomy removes the inflamed tissue that drives this damage, so it works best while joint space is still preserved (Larsen I–III). Once the joint is destroyed (Larsen IV–V) the cartilage is gone and synovectomy has nothing left to preserve — those elbows need arthroplasty.
- Radiographic features
- Normal radiographs, no abnormalities
- Radiographic features
- Soft-tissue swelling and periarticular osteopenia; no erosions
- Radiographic features
- Erosions present; joint space preserved
- Radiographic features
- Joint-space narrowing with less than 50% loss
- Radiographic features
- Joint-space narrowing with greater than 50% loss
- Radiographic features
- Complete joint destruction, ankylosis or obliteration
Open versus arthroscopic synovectomy. A systematic review and meta-analysis (Chalmers, 2011) of 58 studies found arthroscopic and open synovectomy gave similar pain relief, but arthroscopic synovectomy had more frequent recurrence and more radiographic progression; the risk of later arthroplasty was similar, and advanced radiographic disease was not an absolute contraindication. Arthroscopic total synovectomy across all three compartments (anterior, posterior, radiocapitellar) in Larsen 1–3 elbows (Kang, 2010) cut VAS pain from 6.5 to 3.1 and lifted the Mayo Elbow Performance Score from 58.5 to 77.4, with recurrence in 4 of 26 elbows — reinforcing that all compartments must be cleared. Key evidence. The landmark survivorship study (Gendi, 1997) followed 171 rheumatoid elbows after synovectomy with radial head excision: cumulative survival was 81% at 1 year, falling a mean 2.6% per year thereafter, with the strongest predictor of success being marked pre-operative loss of forearm rotation; mean gain was 50° in pronation–supination and 11° in flexion–extension. A comparative long-term study (Schill, 2003) of 120 elbows followed 8–9 years found good or excellent results in 63.3% after synovectomy alone (Larsen 1–2) and 59.4% after synovectomy plus radial head resection (Larsen 3–4), with radiographic progression that did not correlate with clinical outcome. The cadaveric PIN study (Lawton, 2007) quantified the 4 cm safe zone that underpins nerve protection during radial head excision.
References
Synovectomy and radial head excision in the rheumatoid elbow: predictive factors and long-term outcome
- Survival analysis of 171 rheumatoid elbows undergoing elbow synovectomy with radial head excision; failure defined as revision (performed or desired) and/or significant pain
- Cumulative survival 81% at 1 year, thereafter falling by a mean of 2.6% per year - i.e. short-term results good, long-term durability limited
- Strongest predictor of SUCCESS was a low preoperative range of forearm rotation (greater than 50% loss of supination-pronation); a long duration of symptoms before surgery predicted failure
- Mean gain of 50 degrees in supination-pronation and 11 degrees in flexion-extension; failure correlated with recurrent synovitis, instability and ulnar neuropathy
Synovectomy of the rheumatoid elbow (with and without radial head resection): a comparative long-term study
- 120 elbow synovectomies; synovectomy alone for Larsen 1-2 (38 joints) versus synovectomy plus radial head resection for Larsen 3-4 (82 joints), followed a mean of 8 to 9 years
- Good or excellent results (Inglis-Pellicci) in 63.3% after synovectomy alone and a comparable 59.4% after synovectomy with radial head resection - advanced disease still benefited
- Complete pain relief in roughly half of each group; mean gain in pronation-supination of 20 to 25 degrees maintained at final follow-up
- Moderate radiographic progression occurred in both groups but did NOT correlate with clinical outcome
Rheumatoid synovectomy: does the surgical approach matter? (open versus arthroscopic meta-analysis)
- Systematic review and meta-analysis of 58 studies (36 open, 22 arthroscopic), 2589 patients, mean follow-up 6.1 years, for knee and elbow synovectomy
- Arthroscopic and open synovectomy gave SIMILAR pain relief, but arthroscopic synovectomy had more frequent recurrence of synovitis and more radiographic progression
- Risk of subsequent elbow arthroplasty was similar between approaches; advanced preoperative radiographic disease did NOT predict worse pain or greater need for later arthroplasty
- Conclusion: advanced degenerative change should not be treated as an absolute contraindication to synovectomy
Arthroscopic synovectomy for the rheumatoid elbow
- 26 rheumatoid elbows (Larsen grade 3 or less) treated by multi-portal arthroscopic total synovectomy across anterior, posterior and radiocapitellar compartments; mean follow-up 33.9 months
- Mean pain (VAS) fell from 6.5 to 3.1, mean flexion arc improved from 98.1 to 113.3 degrees, and Mayo Elbow Performance Score rose from 58.5 to 77.4
- Radiographs unchanged in 13, improved in 6 and progressed in 7 elbows; clinically apparent synovitis recurred in 4 elbows (the unsuccessful cases)
- Demonstrates the principle that ALL three compartments must be cleared for an adequate synovectomy
Anatomic considerations regarding the posterior interosseous nerve at the elbow
- Cadaveric study (24 specimens) measuring PIN-to-radiocapitellar-joint distance in pronation, neutral and supination
- Mean distance was 4.6 cm in supination, 5.3 cm neutral and 5.7 cm in pronation; minimum recorded distance was 4.0 cm (in supination)
- Contrary to traditional teaching that pronation reliably protects the PIN, pronation did NOT reliably increase the nerve-to-joint distance
- Authors recommend limiting subperiosteal dissection to within 4.0 cm of the radiocapitellar joint regardless of forearm rotation when the PIN is not formally exposed
Additional references 1. O'Driscoll SW, Bell DF, Morrey BF. Posterolateral rotatory instability of the elbow. J Bone Joint Surg Am. 1991;73(3):440-446. (PMID: 2002081) 2. Larsen A, Dale K, Eek M. Radiographic evaluation of rheumatoid arthritis and related conditions by standard reference films. Acta Radiol Diagn (Stockh). 1977;18(4):481-491. doi:10.1177/028418517701800415 (PMID: 920239) 3. Kocher T. Textbook of Operative Surgery. 3rd ed. Adam & Charles Black; 1911. 4. Frohse F, Fränkel M. Die Muskeln des menschlichen Armes. In: von Bardeleben K, ed. Handbuch der Anatomie des Menschen. Vol 2. Gustav Fischer; 1908:223-356.