The proximal row carpectomy (PRC) is a motion-preserving salvage procedure for wrist arthritis in which the scaphoid, lunate, and triquetrum are excised, allowing the capitate to migrate proximally and articulate directly with the lunate fossa of the radius. The procedure was first described by Stamm in 1946 and has since become a well-established treatment for selected patients with SLAC and SNAC wrist arthritis, as well as Kienbock disease.

The fundamental principle: by removing the arthritic proximal carpal row and creating a simplified radiocarpal joint (capitate head into lunate fossa), pain is relieved while retaining a functional arc of wrist flexion and extension. The native lunate fossa cartilage is preserved in SLAC/SNAC wrist because arthritis characteristically spares the radiolunate articulation until very late stages.

Indications:

• SLAC wrist (Watson and Ballet classification): stage I (radioscaphoid arthritis) and stage II (radioscaphoid + scaphocapitate arthritis) with intact lunate fossa and capitate head
• SNAC wrist: analogous stages with preserved lunate fossa and capitate head cartilage
• Kienbock disease (Lichtman stage IIIA or early IIIB): when the lunate is fragmented and beyond salvage but the lunate fossa and capitate head are preserved
• Chronic carpal instability with secondary arthritis limited to the radioscaphoid and midcarpal joints
• Failed prior procedures such as radial shortening or capitate-shortening osteotomy for Kienbock disease

Relative indications:

• Elderly or low-demand patients who prioritise pain relief over maximum grip strength (PRC is simpler than 4CF in this group)
• Manual labourers who understand the functional trade-offs (approximately 50-60% grip strength, approximately 60-65% motion arc)
• Patients who cannot comply with prolonged immobilisation required for four-corner fusion

Carpal architecture relevant to PRC:

• The proximal carpal row (scaphoid, lunate, triquetrum) functions as an intercalated segment between the radius/ulna and the distal carpal row. Its removal fundamentally alters wrist kinematics, converting a complex two-row system into a simplified hinge.
• The lunate fossa is the concave articular surface on the distal radius that normally articulates with the lunate. In SLAC/SNAC wrist, this surface is characteristically preserved because the pathological mechanics of scaphoid collapse and rotatory subluxation load the radioscaphoid joint first.
• The capitate head is the convex proximal surface of the capitate that normally articulates with the scaphoid and lunate at the midcarpal joint. It is slightly smaller in radius of curvature than the lunate fossa, which means the contact area after PRC is reduced compared to the native joint. This size mismatch is the theoretical basis for long-term concern about capitate-lunate fossa degeneration.

SLAC wrist pathomechanics (Watson and Ballet):

• Scapholunate ligament disruption leads to scaphoid flexion (rotatory subluxation) and lunate extension (dorsal intercalated segment instability, DISI).
• The altered scaphoid position concentrates load at the radioscaphoid joint, leading to progressive arthritis.
• Because the lunate extends and rotates dorsally, the radiolunate joint is unloaded and its cartilage is preserved.
• The arthritis cascade follows a predictable sequence: radioscaphoid (stage I), then scaphocapitate (stage II), then capitate head degeneration (stage III), and finally pancarpal involvement including radiolunate (stage IV).

SNAC wrist pathomechanics:

• Similar to SLAC but the initiating event is a scaphoid nonunion rather than scapholunate ligament rupture.
• The fracture creates two fragments: the distal pole (which remains connected to the distal row and maintains some motion) and the proximal pole (which may behave like a free fragment).
• Arthritis develops at the radioscaphoid joint and at the fracture site, but the radiolunate joint is again preserved until late stages.

Kienbock disease and PRC:

• In Lichtman stage IIIA (lunate collapse without fixed scaphoid rotation) and early IIIB (lunate collapse with fixed scaphoid rotation), the lunate is fragmented and avascular beyond salvage.
• PRC removes the diseased lunate and creates a stable capitate-lunate fossa articulation, provided both surfaces are intact.
• This is an alternative to radial shortening osteotomy (for stage II-IIIA with ulnar-neutral or ulnar-positive variance) or lunate replacement/revascularisation procedures.

Dorsal approach (standard for PRC):

• Interval: the approach is developed through the third extensor compartment (containing the extensor pollicis longus, EPL) or in the interval between the extensor digitorum communis (EDC) and the extensor carpi radialis brevis (ECRB). There is no true internervous plane at the wrist because the extensor tendons are all innervated by the posterior interosseous nerve (PIN), but the interval between EDC and ECRB is most commonly used.
• The dorsal retinaculum is divided over the third compartment and the EPL is transposed radially. A radial-based or ulnar-based retinacular flap is raised to expose the underlying extensor tendons and the dorsal wrist capsule.
• The dorsal wrist capsule is opened longitudinally or in an H-shaped fashion to provide wide exposure of the carpus. The capsular flaps are preserved for later repair.
• The posterior interosseous nerve (PIN) is identified on the floor of the fourth extensor compartment, lying on the interosseous membrane just distal to the radial styloid. It is divided for the PIN neurectomy component.

Structures encountered:

• EPL (third compartment): mobilised and protected; usually transposed subcutaneously
• EDC (fourth compartment): retracted ulnarly
• ECRB and ECRL (second compartment): retracted radially
• Radial sensory nerve branches: cross the radial aspect of the wrist in the subcutaneous tissue; must be protected during superficial dissection
• Dorsal capsular ligaments (dorsal radiocarpal ligament, dorsal intercarpal ligament): divided to access the carpus; repair is attempted during closure

• Position: supine with the arm extended on a hand table (arm board). The shoulder is abducted approximately 60-80 degrees and the elbow is flexed. A padded bolster or rolled towel under the wrist facilitates dorsiflexion and exposure.
• Anaesthesia: general or regional anaesthesia (brachial plexus block - supraclavicular, infraclavicular, or axillary). Regional anaesthesia provides excellent post-operative analgesia and is commonly used.
• Tourniquet: a pneumatic tourniquet on the upper arm at 250 mmHg (or 100 mmHg above systolic BP) provides a bloodless field. Exsanguinate with an Esmarch bandage before inflation. Tourniquet time should be kept under 120 minutes.
• Fluoroscopy: an image intensifier is used to confirm complete excision of the proximal carpal row, proper seating of the capitate into the lunate fossa, and to check that no retained bone fragments remain. It is brought in from the head or foot of the table.
• Instrumentation: standard hand surgery instruments, osteotomes, rongeurs, Freer elevator, small Hohmann retractors, and a power burr (for smoothing any irregular bone surfaces). K-wires may be used for temporary fixation if needed.
• Magnification: loupe magnification (2.5x-4.5x) is recommended for precision during dissection and protection of volar ligamentous structures.

PRC has a favourable complication profile compared to four-corner fusion, largely because it avoids hardware-related problems and nonunion risk. However, specific complications must be understood:

• Capitate-lunate fossa degeneration - the most significant long-term concern. Because the capitate head has a slightly smaller radius of curvature than the lunate fossa, contact pressures are higher than in the native joint. Over 10-20 years, degenerative changes may develop at this new articulation, leading to recurrent pain and the need for total wrist fusion. This is the principal argument against PRC in very young patients (under 40-45).

• Volar subluxation of the capitate - if the volar capsuloligamentous structures (RSC ligament, LRL ligament) are damaged during proximal row excision, the capitate may subluxate volarly out of the lunate fossa. This causes pain, weakness, and a palpable volar prominence. Treatment requires capsular reconstruction or conversion to TWF.

• Radial sensory nerve injury - branches of the superficial radial nerve cross the dorsal wrist in the subcutaneous tissue and are at risk during superficial dissection. Neuroma formation causes dorsal wrist and thumb dysesthesia. Meticulous handling and retraction of these branches is essential.

• Extensor tendon irritation or rupture - chronic tenosynovitis or attrition over prominent bone edges (especially a retained scaphoid ridge) may irritate or rupture the EPL, EDC, or EIP tendons. Smooth all bone edges and ensure the retinaculum is repaired to provide a gliding surface.

• Persistent pain - despite technically successful PRC, some patients experience residual wrist pain, particularly with heavy loading or end-range motion. PIN neurectomy reduces but does not eliminate this risk. Patients who smoke or who perform heavy manual labour are at higher risk for persistent symptoms.

• Wrist stiffness - some loss of wrist motion is inherent to the procedure (the new articulation is less mobile than the native two-row system). Post-operative stiffness greater than expected may result from capsular contracture, prolonged immobilisation, or arthrofibrosis. Early protected mobilisation after 3-4 weeks reduces this risk.

• Carpal tunnel syndrome - oedema or haematoma in the carpal tunnel after surgery may compress the median nerve. Pre-operative carpal tunnel symptoms should be addressed with concurrent release.

• Reflex sympathetic dystrophy / complex regional pain syndrome (CRPS) - reported in approximately 2-5% of wrist surgery cases. Early recognition and multidisciplinary management are essential.

There is no single universal guideline specifically for PRC; clinical practice follows evidence-based principles of carpal arthritis management and shared decision-making. Several international hand surgery societies have published consensus guidance:

Key guidance principles:

• ASSH (American Society for Surgery of the Hand, US): PRC is recognised as a motion-preserving salvage option for SLAC/SNAC wrist and Kienbock disease when the lunate fossa and capitate head are preserved. The choice between PRC and four-corner fusion should be individualised based on patient age, demands, articular surface integrity, and surgeon experience.
• BSSH (British Society for Surgery of the Hand, UK): PRC is supported in national guidance as a treatment option for stage II and early stage III SLAC/SNAC wrist. The BSSH outcomes standards recognise both PRC and four-corner fusion as acceptable salvage procedures.
• FESSH (Federation of European Societies for Surgery of the Hand): European practice tends to favour four-corner fusion more than North American practice, though the gap has narrowed. FESSH position papers support both PRC and four-corner fusion as valid options, with the key discriminator being capitate head integrity.

Registry evidence:

• Large-scale national registries for wrist salvage procedures are less developed than arthroplasty registries. However, institutional series and systematic reviews consistently report approximately 80-90% patient satisfaction at 5-10 years and approximately 70-80% satisfaction at 15+ years after PRC.
• Conversion to total wrist fusion after failed PRC is reported in approximately 5-15% of patients at long-term follow-up, with higher conversion rates in younger patients and heavy manual labourers.

Global practice variation:

• European centres have historically favoured four-corner fusion over PRC, reflecting training traditions and concern about long-term capitate-lunate fossa degeneration. However, PRC adoption has increased as long-term data demonstrate acceptable durability.
• North American hand surgeons more commonly perform PRC, particularly in older or lower-demand patients, valuing its simplicity and lower complication rate.
• In Asia-Pacific practice, both procedures are widely used, with some centres reporting excellent results with PRC for Kienbock disease (reflecting the higher prevalence of Kienbock disease in this population).
• In low- and middle-income settings, PRC is valued for its simplicity (no expensive implants, no bone graft harvesting for fusion, shorter operative time) and predictable outcomes.

Conversion to total wrist fusion:

• Total wrist fusion after failed PRC is technically straightforward (no prior hardware to remove, no nonunion to address) and provides reliable pain relief.
• Patients should be counselled pre-operatively about the possibility of future fusion, particularly if they are young or perform heavy manual work.