Calcific Tendinitis of the Shoulder

Epidemiology

Prevalence: Radiographic calcific deposits in roughly 3–8% of adult shoulders, with a higher proportion among symptomatic patients. Peak presentation age 30–60 years. Female slightly predominant. Bilateral in 10–25%. Distinct from degenerative rotator cuff disease — patients are typically younger and the cuff is usually intrinsically intact.

Natural history: This is fundamentally a self-limiting reactive (cell-mediated) calcification, not a degenerative process. Deposits cycle through a formative (resting) phase and a resorptive phase; the resorptive phase (Gärtner Type III) is intensely painful but is precisely when spontaneous resolution occurs — frequently over a few weeks. Many formative (Type I) deposits persist for years with inconsistent symptoms. Spontaneous resorption is the rule rather than the exception (Gärtner and Heyer 1995, PMID 7617385).

Supraspinatus critical zone: Calcification occurs most commonly in supraspinatus (around 70–80% of cases), classically about 1–2 cm proximal to the greater tuberosity insertion — the "critical zone" of relative hypovascularity (Moseley and Goldie 1963). Less common sites: infraspinatus and subscapularis.

Conservative Management

First-line (3 months minimum):

• NSAIDs (e.g. naproxen 500 mg BD) and physiotherapy (pendulum, ROM, posture correction)
• Subacromial corticosteroid injection: reduces acute pain, aids physiotherapy engagement
• Extracorporeal shockwave therapy (ESWT): evidence supports as alternative to barbotage for Type I/II deposits — non-invasive, may take 3–4 sessions

Barbotage Indications and Evidence

Indication: Failed conservative therapy greater than 3 months, particularly Type II/III deposits (soft consistency amenable to aspiration).

Evidence: A randomised controlled trial (de Witte et al. 2013, PMID 23696211) showed ultrasound-guided needling and lavage combined with a subacromial corticosteroid injection produced significantly better Constant scores and greater deposit resorption at 1 year than an isolated subacromial corticosteroid injection (mean Constant 86.0 vs 73.9 at 12 months). A Level I network meta-analysis (Arirachakaran et al. 2017, PMID 27554465) ranked barbotage (with subacromial corticosteroid) as the treatment of choice among non-operative options.

Technical success: Aspiration of chalky/toothpaste-like material is achieved more readily in soft resorptive (Type III) deposits; hard, dense formative (Type I) deposits aspirate poorly and are a recognised cause of barbotage failure.

Post-barbotage: Substantial symptomatic improvement and progressive radiographic resorption are usual over 3–12 months. Repeat barbotage is reasonable for partial response before considering surgery.

Surgical Indications

Operative thresholds (all should be met):

1. Persistent symptoms severe enough to affect quality of life or work
2. Failed minimum 3 months conservative treatment
3. Failed at least one barbotage attempt (or technically impossible — Type I)
4. Imaging confirmation of calcium deposit (plain film + US)

Absolute contraindications: Active shoulder infection, uncontrolled medical comorbidities, patient unwilling to commit to postoperative rehabilitation.

Subacromial Space Anatomy

Dimensions: Subacromial space height 7–14 mm (average 9–10 mm) on outlet view radiograph. Reduced to less than 6 mm suggests impingement or full-thickness rotator cuff tear.

Contents: Subacromial bursa (a synovial-lined potential space between coracoacromial arch superiorly and rotator cuff/greater tuberosity inferiorly), coracoacromial ligament, and the superior surface of the rotator cuff.

Coracoacromial arch: Formed by coracoid process, coracoacromial ligament, and acromion. Protects superior rotator cuff. Acromion morphology (Bigliani classification — Type I flat, Type II curved, Type III hooked): Type III increases impingement risk but is NOT the cause of calcific tendinitis per se.

Critical Zone of Supraspinatus

Location: A region 8–10 mm proximal to the supraspinatus insertion on the greater tuberosity, corresponding to the most anterior portion of the supraspinatus tendon. Described by Moseley and Goldie (1963) as a zone of relative avascularity.

Clinical relevance: This critical zone is the most common site of calcium deposition. During arthroscopic excision, visualise from posterior portal — the deposit appears as a yellowish-white bulge on the bursal surface of supraspinatus; if deposit is intatendinous, needle localisation from the lateral portal guides incision precisely.

Vascularity considerations: Poor blood supply in this zone impairs healing — explains susceptibility to both calcification and rotator cuff tears in the same anatomic region. Post-excision repair should account for tendon quality and vascularity.

Portal Anatomy for Arthroscopic Excision

Posterior portal (viewing): 2 cm inferior and 1 cm medial to posterolateral acromion corner. Primary viewing portal for subacromial space.

Lateral portal (working): 2–3 cm lateral to acromion mid-point. Working portal for shaver, burr, and suture anchors during cuff repair. Used for transcutaneous needle localisation.

Anterolateral portal: Occasionally added for additional working access or suture anchor placement in cuff repair.

Axillary nerve: Exits quadrilateral space and travels anteriorly — 5–6 cm below the acromion. No risk during standard subacromial arthroscopy unless portals placed too far distally.

Barbotage — Step-by-Step

Patient position: Supine or sitting (high chair), arm in slight internal rotation to bring supraspinatus into view.

Imaging: High-frequency (15 MHz) linear ultrasound probe. Long-axis view of supraspinatus — deposit appears as hyperechoic focus with posterior acoustic shadowing, within tendon substance.

Step 1: Skin preparation and local anaesthesia: Sterile prep, 5 mL 1% lidocaine superficial infiltration to skin and subcutaneous tissue. Flush probe in sterile sleeve.

Step 2: Needle placement: 18G needle introduced in-plane with US beam (dynamic needle tip visualisation). Advance to calcium deposit. First puncture to confirm position.

Step 3: Lavage and aspiration: Two-needle technique preferred (one inlet, one outlet) or single-needle pulsed technique. Inject saline in 2–5 mL aliquots, aspirate back — repeat 10–15 cycles. Aspirate chalky white/milky material. Volume aspirated varies — may be minimal even with successful fragmentation.

Step 4: Corticosteroid injection: Optional. 1 mL methylprednisolone acetate 40 mg co-injected into subacromial bursa (not into tendon) to reduce post-procedure flare.

Step 5: Post-procedure care: Ice, analgesia, sling for 24–48 hours. Expect post-procedure flare (pain worse 24–72 hours as calcium crystal shower). Physiotherapy from day 3.

Arthroscopic Excision — Step-by-Step

Patient position: Beach chair (preferred) or lateral decubitus. General anaesthesia or interscalene block.

Step 1: Examination under anaesthesia: Document ROM, Hawkins-Kennedy, Neer sign, cross-body adduction — confirms impingement component.

Step 2: Glenohumeral joint inspection: Insert arthroscope through posterior portal into glenohumeral joint. Inspect articular surfaces, labrum, biceps anchor, and articular-side of rotator cuff. Document any articular-side partial tears.

Step 3: Subacromial bursoscopy: Withdraw arthroscope, redirect through posterior portal into subacromial space. Establish lateral working portal. Perform thorough bursectomy with motorised shaver — remove inflamed bursal tissue to improve visualisation.

Step 4: Identify calcium deposit: Inspect bursal surface of supraspinatus systematically. Deposit appears as yellowish-white bulge or chalk-coloured mass (Type I: firm; Type III: soft/expressive). If not immediately visible, palpate with probe — focal firmness identifies location.

Step 5: Needle localisation: Pass 18G needle transcutaneously from lateral portal into subacromial space, directing it towards suspected deposit. Under arthroscopic vision, identify needle tip touching tendon. This provides accurate localisation before incising tendon.

Step 6: Tendon incision and calcium removal: Using arthroscopic knife or electrocautery through lateral portal, make longitudinal incision over deposit (parallel to tendon fibres to minimise strength loss). Curette or shaver debrides calcium — remove until normal-appearing tendon exposed. Express remaining calcium with probe. Thorough irrigation.

Step 7: Tendon assessment: Probe residual tendon to assess thickness. Classify defect as less than 25%, 25–50%, or greater than 50% of tendon thickness. If greater than 50%: proceed to formal rotator cuff repair (suture anchor technique, single or double row depending on defect width).

Step 8: Concomitant SAD (if indicated): Visualise coracoacromial arch from lateral portal. If hooked acromion or frayed CA ligament: acromioplasty with arthroscopic burr (5–8 mm inferior acromion), smooth to flat/Type I profile. Preserve CA ligament if no impingement.

Step 9: Wound closure and dressing: Close portal wounds. Intra-articular bupivacaine/morphine injection if not blocking. Sling applied.

Technical Tips and Pitfalls

Finding the Deposit When Not Immediately Visible

The most common intraoperative challenge is a deposit that does not produce an obvious bursal bulge. Systematic approach: (1) Thorough bursectomy to clear all inflamed tissue from the superior rotator cuff. (2) Palpate the supraspinatus surface with a blunt probe — Type I calcium feels firm/hard; Type III may feel slightly soft compared to normal tendon. (3) Transcutaneous 18G needle localisation — essential step before incising. (4) If still not found: fluoroscopy with C-arm confirms needle position relative to calcium on plain film. (5) Very rarely: deposit is purely intatendinous without bursal expression — requires careful longitudinal incision over X-ray–confirmed location, or conversion to limited open (1.5 cm mini-open incision over deposit).

Rotator Cuff Repair After Excision — Technique Detail

For defects requiring repair (greater than 50% thickness):

Single-row repair (defects less than 2 cm wide): One suture anchor placed at the medial footprint margin. Mason-Allen stitch or modified mattress passed through tendon margin. Tie with arm in neutral abduction (30°). Confirm repair integrity with probe.

Double-row repair (defects 2–3 cm wide or in high-demand patients): Medial row anchor at articular margin (2 × #2 sutures per anchor), lateral row "knotless" anchors at lateral footprint. Lateral row sutures crossed from medial row to compress repair — transosseous-equivalent (TOE) construct. This maximises footprint contact area and repair strength.

Anchor placement landmark: Medial row: at or just medial to the articular margin of the greater tuberosity. Lateral row: 5–8 mm lateral to medial row. Use standard arthroscopic angle — typically 45° to bone surface.

Intraoperative Complications

Failure to Identify Deposit

Risk factors: Type I (hard, dense, intatendinous), small deposits, inadequate bursectomy obscuring view.

Prevention: Thorough bursectomy before inspecting tendon, systematic inspection from anterior to posterior, transcutaneous needle localisation mandatory if deposit not visible. Use fluoroscopy if needed.

Management: Extend bursectomy, palpate systematically, use C-arm fluoroscopy to confirm needle tip in deposit area. If deposit completely intatendinous and not accessible: consider postoperative repeat imaging and delayed re-arthroscopy or open technique (rare).

Excessive Tendon Excision

Risk: Aggressive debridement leaving greater than 50% tendon defect. Higher risk with large intatendinous deposits.

Prevention: Longitudinal incision parallel to fibre direction, minimal bone trough, preserve tendon margin. Use curette rather than aggressive shaver.

Management: Formal rotator cuff repair (suture anchor — 1 or 2 anchors for small/medium defect). Document defect size and repair technique.

Axillary Nerve Injury

Risk: Portals placed too far distally, aggressive retraction during SAD.

Prevention: Keep portal placement within 3 cm of acromion edge; nerve is 5–6 cm below acromion.

Postoperative Complications

Post-procedure Flare (Barbotage)

Incidence: 30–40% experience 24–72 hour pain flare after barbotage from calcium crystal shower in bursa.

Management: Warn patients pre-procedure. NSAIDs, ice, analgesia. Settles spontaneously. Not a failure of procedure.

Incomplete Resolution of Calcium

Incidence: 10–20% have residual calcium on imaging post-barbotage; most are asymptomatic.

Decision: Residual calcium on imaging without symptoms — observe. Persistent symptoms with residual deposit — repeat barbotage or proceed to arthroscopic excision.

Rotator Cuff Weakness / Stiffness

Risk: Post-excision adhesion, unrepaired large defect, excessive immobilisation.

Prevention: Early physiotherapy, repair defects greater than 50%, structured rehabilitation protocol.

Management: Physiotherapy, steroid injection for secondary impingement. MRI if suspected re-tear.

Post-barbotage Protocol

Day 0–2: Sling for comfort, ice 20 minutes every 2 hours, oral analgesia (NSAIDs + paracetamol).

Day 3 onwards: Discard sling. Begin pendulum exercises and active ROM as tolerated. Physiotherapy referral.

Week 2–6: Progressive strengthening program. Subacromial loading exercises, rotator cuff activation.

Review at 6 weeks: Clinical and US assessment. If good response — continue physiotherapy. If no response — consider repeat barbotage or surgical referral.

Post-arthroscopic Excision Protocol

Without Rotator Cuff Repair

Weeks 0–2: Sling for comfort only (not structural). Early pendulum exercises. Wound care.

Weeks 2–6: Discard sling. Active ROM exercises. Progressive physiotherapy.

Weeks 6–12: Strengthening — rotator cuff, deltoid, periscapular muscles.

Weeks 12–24: Return to sport/heavy work.

Expected outcomes: 85–90% excellent or good results. Pain-free in 70% at 3 months. Full recovery 4–6 months.

With Rotator Cuff Repair

Weeks 0–6: Sling immobilisation. Passive ROM only (pendulums, physiotherapy-assisted). No active elevation.

Weeks 6–12: Active-assisted ROM. Gradual active elevation. No resisted exercise.

Weeks 12–24: Progressive strengthening (resistance bands, weights). Pool therapy encouraged.

Weeks 24+: Return to full activity. Heavy overhead work from 6 months.

Expected Outcomes

Barbotage: Significant pain and function improvement is usual, with progressive radiographic resorption over 6–12 months; barbotage plus subacromial corticosteroid outperforms steroid injection alone at 1 year (de Witte et al. 2013, PMID 23696211).

Arthroscopic excision: Reliable for deposits refractory to non-operative treatment. The original arthroscopic series (Ark et al. 1992, PMID 1637430) reported 50% good and 41% satisfactory results in chronic resistant cases; modern series with arthroscopic removal and repair of any significant cuff defect report good/excellent outcomes in roughly 85–90%. Return to full function typically 3–5 months (longer if a cuff repair was performed).

Acromioplasty: Routine acromioplasty adds no benefit in isolated calcific tendinitis without structural impingement — outcome is determined by adequacy of calcium removal, not by acromioplasty. Reserve SAD for genuine concomitant impingement.