Repair of the ruptured ulnar collateral ligament of the thumb MCP joint — acute suture-anchor repair and chronic free-graft reconstruction | intermediate
- A Stener lesion is the torn UCL end folded back and interposed BETWEEN the adductor aponeurosis and the proximal phalanx base — the aponeurosis blocks spontaneous healing, so surgery is mandatory whenever a Stener lesion is present.
- Stress test in BOTH 0 degrees (accessory UCL taut) and 30 degrees MCP flexion (proper UCL taut). Greater than 35 degrees of radial deviation, OR greater than 15 degrees side-to-side difference, OR an absent firm end-point equals a complete tear requiring surgical evaluation.
- The proper UCL is the primary restraint in flexion; the accessory UCL is the primary restraint in extension. Both must be assessed — isolated accessory UCL tears may heal non-operatively.
- Reflect (do NOT divide) the adductor aponeurosis: repair the UCL deep to it, then close the aponeurosis over the repair as a second layer. Repairing the UCL while it is still superficial to the aponeurosis simply recreates a Stener lesion.
- The superficial (dorsal sensory) branch of the radial nerve crosses the field only 2 to 3 mm deep in the subcutaneous plane — a neuroma here is the most common nerve complication of the operation.
When & Why
The indication. A complete rupture of the ulnar collateral ligament (UCL) of the thumb metacarpophalangeal (MCP) joint — the so-called skier's or gamekeeper's thumb — in which the torn ligament cannot heal spontaneously. The decision to operate rests on the stress examination and on whether a Stener lesion is present.
How to read the stress test. Apply radial-directed (valgus) stress with the MCP first in full extension (tests the accessory UCL) and then in 30 degrees flexion (isolates the proper UCL), always comparing with the contralateral thumb. A complete tear is present when the proximal phalanx angulates 30 to 35 degrees or more in either position, when there is greater than 15 degrees of side-to-side difference, or when there is no firm end-point. Heyman's prospective series found a Stener lesion in 15 of 17 (87 percent) of thumbs with greater than 35 degrees of laxity in extension — gross instability reliably predicts a displaced, operative ligament. Operate — absolute indication. A complete tear with a confirmed or likely Stener lesion. Across the literature a Stener lesion is present in 60 to 87 percent of complete tears, so most clinically complete tears warrant surgical exploration. Also operate for an associated avulsion fracture at the proximal phalanx base with greater than 2 mm displacement or greater than 20 percent articular surface involvement. Do not operate. An incomplete tear (less than 15 degrees side-to-side difference, firm end-point) is managed non-operatively in a short thumb spica for 4 to 6 weeks; a complete tear with MRI confirmation that NO Stener lesion is present may also be treated non-operatively in a reliable patient (uncommon). Chronic insufficiency (greater than 6 weeks — true gamekeeper's thumb). Presents with functional pinch and grip weakness, pain on lateral stress, and difficulty with key pinch. Direct repair is usually impossible because the ligament is attenuated and scarred; reconstruction (free tendon graft or adductor advancement) is offered if the joint is pre-arthritic and conservative treatment has failed. With established MCP arthritis, MCP arthrodesis is preferred over ligament reconstruction. Contraindicated in the presence of active infection, severe MCP arthritis (reconstruct the joint, not the ligament), or poor soft-tissue cover; relative contraindications are the elderly low-demand patient and significant medical comorbidity. The one decision that matters — timing drives the operation:
Injury less than 6 weeks with a Stener lesion. Suture-anchor reattachment of the UCL to its proximal phalanx footprint. Tissue is identifiable and holds an anchor — greater than 90 percent good or excellent results.
Injury greater than 6 weeks with an attenuated, scarred ligament. Palmaris-longus (or plantaris) graft through metacarpal-head and proximal-phalanx bone tunnels. Restores near-symmetrical strength and stability in most patients.
Established MCP arthritis or a failed reconstruction. MCP fusion gives reliable stability at the cost of MCP motion. The last rung of the treatment ladder.
Confirm the Stener lesion before cutting. MRI shows the UCL stump lying proximal and superficial to the adductor aponeurosis (the 'yo-yo sign'). A pooled meta-analysis (Qamhawi, 2021) found MRI sensitivity 93 percent and specificity 98 percent, and dynamic ultrasound sensitivity 95 percent and specificity 94 percent — ultrasound is an appropriate lower-cost first-line test where expertise exists. Consent specifically for radial-sided numbness or a tender neuroma (the commonest nerve complication), some loss of pinch or MCP motion, a small risk of recurrent instability, and (for reconstruction) palmaris donor-site symptoms. Setup. Supine, arm on a hand table, forearm pronated so the dorso-ulnar aspect of the thumb faces upward; upper-arm tourniquet at 250 mmHg (or forearm at 200 mmHg). WALANT (1 percent lidocaine with 1:100,000 epinephrine, 5 to 7 mL) or a regional block is usually sufficient; general anaesthesia for the anxious or for combined procedures. Loupe magnification (2.5 to 3.5x) is mandatory — identifying the fine nerve branches is the whole game. Have fluoroscopy available for anchor and K-wire position.
The Operation
The goal: through a dorso-ulnar exposure, protect the superficial radial nerve, reflect (not divide) the adductor aponeurosis, reduce any Stener lesion back beneath the aponeurosis, and reattach the UCL to its footprint on the proximal phalanx base with a mini suture anchor — then close the aponeurosis over the repair as a second layer. For a chronic injury, the same exposure is used to reconstruct the ligament with a free tendon graft.
Acute repair — operative sequence
- A gently curved (lazy-S) dorso-ulnar incision over the thumb MCP joint, about 3 to 4 cm long, beginning over the metacarpal neck and curving distally toward the mid-axial line of the proximal phalanx.
- Deliberately curve AWAY from the volar midline to stay clear of the digital neurovascular bundle, and avoid crossing skin creases at right angles (reduces scar tethering).
- In the subcutaneous plane, identify and protect the fine cutaneous branches of the superficial (dorsal sensory) radial nerve — they cross the field transversely only 2 to 3 mm deep and are the structure most often injured.
- Dissect around them with fine spreading scissors and retract gently with a vessel loop; no cautery near the branches.
- Deepen to the adductor aponeurosis — a dense white fibrous sheet overlying the UCL and capsule. Do NOT divide it.
- Develop the plane between the aponeurosis and the underlying capsule and reflect the aponeurosis proximally and radially as a flap, exposing the UCL beneath.
- In a Stener lesion the torn UCL stump lies SUPERFICIAL to the aponeurosis — a thickened cord just proximal to its edge (the 'yo-yo'). Gently free and reduce it back to its correct DEEP position before repair.
- With the aponeurosis retracted, identify the UCL complex and its torn distal stump (avulsed from the proximal phalanx base); the capsule is often torn with it.
- Open the capsule in line with the incision and confirm there is no significant cartilage damage or osteochondral fracture that would change the plan.
- Locate the UCL footprint — the ulnar-palmar corner of the proximal phalanx base, about 5 mm distal to the joint line.
- Select a mini suture anchor (1.3 to 1.5 mm, double-loaded with 2-0 or 3-0 braided non-absorbable suture).
- Under fluoroscopy, seat the anchor at the UCL footprint on the ulnar-palmar corner of the proximal phalanx base, in subarticular bone 2 to 3 mm from the joint surface without breaching cartilage. Confirm solid purchase with a pull-test.
- Pass the anchor sutures through the UCL stump in a locking (mattress or Kessler) configuration, taking 5 to 7 mm of purchase back from the torn edge.
- With the MCP reduced and held in 10 to 15 degrees flexion (the resting position that puts slight tension on the UCL), tie the sutures and seat the stump firmly against the footprint.
- Test the repair: gentle radial-directed stress in 30 degrees flexion and in extension — the joint should feel stable with no perceptible laxity.
- Repair the reflected aponeurosis over the reconstruction with 3-0 Vicryl interrupted sutures, restoring the normal layered arrangement and re-establishing the secondary stabiliser.
- If tissue quality is borderline, repair tension marginal, or compliance uncertain, pass a 1.4 mm K-wire transarticularly across the MCP joint in 10 to 15 degrees flexion and confirm position on fluoroscopy. Remove at 4 weeks under local anaesthesia.
- Close subcutaneous tissue (4-0 Vicryl) and skin (4-0 nylon). Release the tourniquet and confirm thumb perfusion.
- Apply a thumb spica with the MCP in 20 degrees flexion and slight ulnar deviation, the IP joint FREE. Splint for 4 weeks (6 weeks if a K-wire was used or tissue quality is poor).
The adductor aponeurosis must be REFLECTED, not divided. Repair the UCL deep to it, then close the aponeurosis over the top as a second layer. If you repair the UCL while it is still lying superficial to the aponeurosis, you have simply rebuilt a Stener lesion and the repair will fail. Confirm the stump is reduced beneath the aponeurosis before you tie.
Place the anchor at the ulnar-palmar corner of the proximal phalanx base, 5 mm distal to the joint line. Too dorsal and you reconstruct the accessory UCL (laxity persists in flexion); too close to the articular surface and you risk cartilage injury or anchor pull-through. If the bone will not hold an anchor, fall back to a transosseous suture through drill holes.
Make a gently curved dorso-ulnar incision starting over the metacarpal neck and curving distally, staying dorsal to the volar midline to avoid the digital neurovascular bundle. In the subcutaneous tissue look immediately for the fine transverse branches of the superficial radial nerve and dissect around them with spreading scissors — a neuroma in the thumb is debilitating.
If an avulsion fragment is carried with the UCL and is displaced greater than 2 mm or involves greater than 20 percent of the articular surface, fix the fragment back to its bed with the same anchor or a K-wire — the operative principle (reduce beneath the aponeurosis, restore the footprint) is identical.
Chronic reconstruction — free tendon graft (greater than 6 weeks) When the ligament is attenuated and scarred, direct repair will not hold. Through the SAME dorso-ulnar exposure and adductor reflection:
Chronic reconstruction sequence
- Confirm palmaris longus is present pre-operatively (absent in about 15 percent). Harvest 12 to 15 cm through two small transverse forearm incisions, protecting the median nerve under direct vision.
- If palmaris is absent, use plantaris (20 to 25 cm) or an allograft.
- Debride the scarred UCL remnant and identify the origin (metacarpal head) and insertion (proximal phalanx base) footprints.
- Drill a 3.5 mm tunnel through the metacarpal head (ulnar-distal to radial-dorsal) and a 3.5 mm tunnel through the proximal phalanx base (ulnar to radial).
- Pass the graft through the distal tunnel first, then the proximal tunnel, in a figure-of-eight or loop configuration.
- Tension with the MCP in 10 to 15 degrees flexion and confirm stability; secure the ends with a 2.7 to 3.5 mm interference screw or transosseous suture tied over a bone bridge.
- Protect with a transarticular K-wire for 6 weeks. Close the adductor aponeurosis over the reconstruction as a second layer.
Aftercare & Complications
Rehabilitation — acute repair | Phase | Timing | Splint and motion | Focus | |-------|--------|-------------------|-------| | 1 | 0 to 4 weeks | Thumb spica, MCP 20 degrees flexion, slight ulnar deviation, IP FREE | IP motion from day 1 (FPL glide); elevation and ice for 48 hours | | 2 | 4 to 6 weeks | Wean from static splint; protective splint for risk | Gentle active MCP ROM; scar care | | 3 | 6 to 12 weeks | Splint only for heavy or risk activity | Progressive active and resistive MCP motion; grip and pinch from week 6 | | 4 | 12 weeks and beyond | Full activity | Non-contact sport from week 12; contact sport and manual work 12 to 16 weeks | If a K-wire was used it is removed at 4 weeks (under local anaesthesia) and motion begun immediately. Chronic reconstructions are protected for 6 weeks in a spica with a K-wire, then progress more slowly, with return to contact sport at 16 to 20 weeks. Functional milestones — acute repair versus chronic reconstruction | Milestone | Acute repair | Chronic reconstruction | |-----------|--------------|------------------------| | K-wire removal | 4 weeks | 6 weeks | | Begin active MCP ROM | Week 4 | Week 6 | | Begin pinch strengthening | Week 6 | Week 8 | | Return to office work | 4 to 6 weeks | 6 to 8 weeks | | Return to manual work | 8 to 10 weeks | 12 to 14 weeks | | Return to contact sport | 12 to 16 weeks | 16 to 20 weeks | | Final strength assessment | 6 months | 9 to 12 months | Acute repair returns greater than 90 percent of patients to their previous activity; chronic reconstruction gives 80 to 88 percent good or excellent results. Pinch strength typically reaches 85 to 95 percent and MCP ROM 80 to 90 percent of the contralateral side. Complications
- Incidence
- 2 to 5 percent
- Recognition
- Painful dysaesthetic scar with a positive Tinel sign over the dorsal MCP; allodynia of the thumb dorsum
- Prevention and management
- Prevention: identify and protect every fine branch in the subcutaneous plane, no cautery near the nerve. Management: observe 3 to 6 months, gabapentin or pregabalin; excise and bury the neuroma if no improvement at 6 months
- Incidence
- 5 to 10 percent at 5 years
- Recognition
- Return of radial-deviation laxity on stress testing, progressive pinch weakness, pain on lateral stress
- Prevention and management
- Prevention: solid anchor purchase, correct footprint, K-wire protection if borderline, compliant rehab. Management: revision free-graft reconstruction, or MCP arthrodesis if cartilage is damaged
- Incidence
- 10 to 20 percent
- Recognition
- Reduced MCP arc at 3 months, pain at end of range, unable to make a full fist
- Prevention and management
- Prevention: K-wire out at 4 weeks, IP free from day 1, early hand therapy. Management: formal ROM therapy, dynamic splinting, manipulation under anaesthesia if persistent at 6 months
- Incidence
- 3 to 8 percent
- Recognition
- Pin-site erythema or discharge, painful pin, broken pin on X-ray
- Prevention and management
- Prevention: remove at 4 weeks, keep dry, 1.4 mm minimum, bend away from the joint. Management: oral antibiotics for pin infection; fluoroscopic retrieval of a broken or migrated pin
- Incidence
- less than 1 percent
- Recognition
- Sensory loss or paraesthesia in a digital distribution; cold sensitivity or ischaemia
- Prevention and management
- Prevention: keep the incision dorso-ulnar, identify the digital NV bundle before retracting. Management: immediate microsurgical nerve repair; restore arterial inflow if ischaemic
- Incidence
- 2 to 5 percent
- Recognition
- Scar tenderness at the forearm harvest site; median nerve injury from errant harvest
- Prevention and management
- Prevention: confirm palmaris present, small incisions, direct-vision harvest. Management: scar massage; immediate exploration for a median nerve injury
- Incidence
- 5 to 15 percent at 10 years
- Recognition
- Progressive MCP pain, stiffness, crepitus; X-ray narrowing, sclerosis, osteophytes
- Prevention and management
- Prevention: early anatomic repair to restore joint mechanics. Management: conservative first; MCP arthrodesis (young, active) or silicone arthroplasty (low-demand elderly)
- Incidence
- less than 1 percent
- Recognition
- Erythema, warmth, purulent discharge, fever
- Prevention and management
- Prevention: sterile technique, perioperative antibiotics if implants used. Management: oral antibiotics (superficial); debridement and retain or remove hardware (deep)
Viva & Exam Focus
STENERSTENER — diagnosis and management
Clinical Decision Scenarios
Practise clinical reasoning and management decisions out loud
“A 28-year-old skier presents after a fall 4 hours ago with acute pain, swelling and tenderness over the ulnar side of the right thumb MCP joint. On stress testing, radial deviation in 30 degrees MCP flexion is 40 degrees (contralateral 20 degrees — a 20-degree side-to-side difference), with end-point laxity in full extension. What is the diagnosis and how do you manage this?”
“A 55-year-old farmer presents with a 6-week history of pain and instability of the right thumb MCP joint after an injury sustained while pulling a calf, with ongoing weakness of pinch and grip. On examination there is 25 degrees of side-to-side laxity in 30 degrees flexion, and MRI shows chronic UCL changes with an attenuated, scarred ligament. What are the surgical options and how do you choose between them?”
“A patient is 4 months after acute UCL repair with suture anchors. She complains of ongoing pinch weakness and the physiotherapist reports grip strength of only 60 percent of the contralateral side. On examination there is mild residual laxity at the thumb MCP in 30 degrees flexion (10 degrees side-to-side difference). How do you assess and manage this?”
Diagnosis
- Mechanism: forced radial deviation (valgus) — ski-pole strap, ball sports, a fall onto an abducted thumb
- Stress test BOTH 0 degrees (accessory UCL) AND 30 degrees flexion (proper UCL)
- Complete tear: greater than 35 degrees absolute, OR greater than 15 degrees side-to-side, OR no firm end-point
- Stener lesion in 60 to 87 percent of complete tears — surgery is mandatory
- MRI 'yo-yo sign' (sensitivity 93 percent); ultrasound is an appropriate first-line test
Anatomy
- Proper UCL: posterior-inferior metacarpal head to the ulnar base of the proximal phalanx; taut in FLEXION
- Accessory UCL: to the sesamoid and volar plate; taut in EXTENSION
- Adductor aponeurosis lies SUPERFICIAL to the UCL — in a Stener lesion the stump is superficial to it
- Superficial radial nerve branches cross the dorsal field — neuroma is the commonest nerve complication
- UCL footprint: ulnar-palmar corner of the proximal phalanx base, 5 mm distal to the joint line
Indications
- Acute (less than 6 weeks) complete tear or Stener lesion — anchor repair
- Incomplete tear (less than 15 degrees side-to-side) — non-operative spica for 4 to 6 weeks
- Chronic (greater than 6 weeks), no arthritis — free tendon graft
- Established MCP arthritis — MCP arthrodesis
- Avulsion fracture greater than 2 mm or greater than 20 percent of the surface — operative fixation
Acute repair steps
- Dorso-ulnar curved incision (3 to 4 cm), away from the volar NV bundle
- Protect the superficial radial nerve branches
- REFLECT the adductor aponeurosis; reduce any Stener lesion deep to it
- Mini anchor (1.3 to 1.5 mm) at the UCL footprint
- Repair with locking sutures, MCP in 10 to 15 degrees flexion
- Close the aponeurosis as a second layer
- Optional K-wire for 4 weeks; thumb spica with the IP free
Chronic reconstruction
- Palmaris longus graft (12 to 15 cm; absent in 15 percent — confirm pre-operatively)
- 3.5 mm bone tunnels in the metacarpal head and proximal phalanx base
- Tension with the MCP in 10 to 15 degrees flexion; interference-screw fixation
- K-wire protection for 6 weeks (versus 4 for acute)
- Near-symmetrical strength and stability in most patients (Basar 2014)
Danger zones
- Superficial radial nerve — fine dorsal branches, neuroma risk
- Adductor aponeurosis — reflect not divide; interposition recreates a Stener lesion
- Anchor — too dorsal reconstructs the wrong ligament; too close to the surface risks cartilage injury
- Ulnar digital nerve — keep the dissection dorsal
Complications
- Superficial radial nerve neuroma (2 to 5 percent)
- Repair failure (5 to 10 percent at 5 years)
- MCP stiffness (10 to 20 percent)
- K-wire problems (3 to 8 percent)
- Post-traumatic MCP arthritis (5 to 15 percent at 10 years)
Radial collateral ligament
- Less than 10 percent of thumb collateral injuries; forced ulnar deviation
- Same stress-test and operative principles
- Radial incision — protect the thenar branch of the radial nerve
- Outcomes comparable to UCL repair when treated with the same principles
Background & Evidence
Mechanism and epidemiology. A thumb UCL rupture follows forced radial deviation (valgus) of the MCP joint — the classic ski-pole strap injury (skier's thumb), ball sports, or a fall onto an abducted thumb. The chronic repetitive form is gamekeeper's thumb, originally described in Scottish gamekeepers from twisting rabbit necks. It is one of the most common ligament injuries of the hand; radial collateral ligament injuries are far less common (less than 10 percent of thumb collateral injuries).
Pathoanatomy — the two bands and the aponeurosis. The UCL has two components. The proper collateral ligament arises from the posterior-inferior metacarpal head and inserts on the ulnar base of the proximal phalanx; it is taut in flexion and is the primary restraint to radial deviation during pinch. The accessory collateral ligament arises just dorsal to the proper ligament and inserts on the sesamoid and volar plate; it is taut in extension. The adductor aponeurosis — the broad insertion of adductor pollicis — runs superficial (volar) to the UCL complex. The Stener lesion mechanism. When the UCL avulses from the proximal phalanx base, the ligament end retracts proximally as the MCP extends, and the adductor aponeurosis catches it and holds it superficial to the aponeurosis. The aponeurosis is now INTERPOSED between the UCL stump and its insertion — there is no contact, and healing is impossible without surgical reduction of the stump back beneath the aponeurosis. This is why a Stener lesion cannot be managed in a cast. The footprint and the danger structures. The proper UCL inserts at the ulnar-palmar corner of the proximal phalanx base, about 5 mm distal to the joint line — the target for the suture anchor. The superficial (dorsal sensory) branch of the radial nerve crosses the operative field; the digital neurovascular bundle lies volar and is protected by keeping the incision dorso-ulnar. The extensor pollicis longus runs dorsally and must not be confused with the aponeurotic tissue.
- Treatment
- Direct repair with suture anchors
- Expected outcome
- Greater than 90 percent good or excellent at 2 years
- Treatment
- Short thumb spica 6 weeks — non-operative
- Expected outcome
- 85 to 90 percent satisfactory without surgery
- Treatment
- Short thumb spica 4 to 6 weeks
- Expected outcome
- 90 percent satisfactory non-operative
- Treatment
- Free tendon graft reconstruction
- Expected outcome
- 80 to 88 percent good or excellent at 2 to 5 years
- Treatment
- Adductor advancement
- Expected outcome
- 70 to 80 percent good or excellent; simpler procedure
- Treatment
- MCP arthrodesis
- Expected outcome
- Reliable stability; loses MCP motion
Key evidence. Stener (1962) first described the adductor-aponeurosis interposition that bears his name and established why complete tears require operation. Heyman (1993) showed prospectively and biomechanically that greater than 35 degrees of valgus laxity in extension indicates a complete (proper plus accessory) tear, with a Stener lesion in 15 of 17 such thumbs. Tang (2011) and Rhee (2012) codified the examination thresholds and the acute-repair, chronic-reconstruction and arthrodesis ladder. Qamhawi (2021) confirmed in meta-analysis that MRI (sensitivity 93 percent) and dynamic ultrasound (95 percent) reliably detect the Stener lesion. Basar (2014) showed that free-graft reconstruction restores near-symmetrical strength and stability for chronic injury.
References
Displacement of the ruptured ulnar collateral ligament of the metacarpo-phalangeal joint of the thumb
The original description of the adductor-aponeurosis interposition mechanism — the foundational paper establishing why a complete UCL tear with a displaced stump cannot heal and requires operation. Pre-dates reliable PubMed indexing.
Injuries of the ulnar collateral ligament of the thumb metacarpophalangeal joint — biomechanical and prospective clinical studies on valgus stress testing
Cadaverically, dividing the proper collateral ligament markedly increased valgus laxity in MCP flexion; adding the accessory ligament and palmar plate increased laxity in extension to match. Clinically, valgus instability greater than 35 degrees in extension consistently indicated tears of BOTH bands, and a Stener lesion was present in 15 of 17 (87 percent) of such thumbs. Stress testing in BOTH extension and 30 degrees flexion is therefore essential.
Management of thumb metacarpophalangeal ulnar collateral ligament injuries
Instructional review of the diagnostic and treatment ladder: partial tears are treated non-operatively; acute complete or displaced (Stener) tears by operative repair; chronic injuries by static or dynamic ligament reconstruction; and MCP arthrodesis reserved as salvage when painful arthrosis coexists with instability.
Diagnostic accuracy of ultrasound and MRI in detecting Stener lesions of the thumb — systematic review and meta-analysis
Pooled analysis of 9 ultrasound studies (315 thumbs) and 6 MRI studies (107 thumbs): ultrasound sensitivity 95 percent and specificity 94 percent; MRI sensitivity 93 percent and specificity 98 percent. Both are highly accurate; ultrasound is endorsed as an appropriate lower-cost first-line modality where expertise exists.
Comparison of results after surgical repair of acute and chronic ulnar collateral ligament injury of the thumb
In 19 chronic UCL ruptures reconstructed with a free tendon graft fixed as biotenodesis with interference screws, there was no significant difference versus the contralateral thumb in grip, tip-pinch, flexion, extension or deviation; 16 of 19 regained full stability and the remainder only mild residual laxity (less than 10 degrees), with excellent or good Glickel grades. Displaced avulsion fractures were managed by closed reduction and K-wire.
Collateral ligament injuries of the thumb metacarpophalangeal joint
A complete tear is diagnosed when the proximal phalanx angulates 30 to 35 degrees in full extension or 30 degrees flexion, when there is greater than 15 degrees side-to-side difference, or when there is no firm end-point. Partial injuries are managed non-operatively; complete tears are usually operative — suture-anchor reattachment for acute injury, free graft or arthrodesis for chronic injury — for both UCL and RCL injuries.