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ULNAR IMPACTION SYNDROME (ULNAR CARPAL ABUTMENT)

Introduction

Ulnar impaction syndrome is one of several causes of ulnar-sided wrist pain. Ulnar impaction syndrome occurs when the normal length relationshionships between the ulna and radius are abnormal.  In ulnar impaction syndrome the ulna is disproportionally longer than the radius.  This length discrepancy is called positive (+) ulnar variance.  Conditions that can led to positive ulnar variance include premature closure of the radial epiphyseal plate, malunions of distal radius fracutres, prior radial head excison and Essex-Lopresti injuries [interosseous membrane injuries (IOM) injuries].1,2,13

Pathophysiology

  • Excessive load is transferred from the distal ulna, through the triangular fibrocartilage complex (TFCC), to the ulnar carpus (in particular the ulnar corner of lunate) leading to degenerative changes in those structures.
  • The TFCC normally functions as shock absorber between the head of the ulna and the lunate. When the TFCC is damaged, for example by a large central TFCC tear, the ulna head will repetively and forcefully hit the lunate during power grip.  These increased forces that must be aborbed by the cartilage of the lunate and ulnar head will eventually damage the carilage covering these surfaces and lead to degenerative arthitis.
  • As noted above the cause of excessive load transfer is usually positive (+) ulnar variance,1 either congenital or the result of trauma to the radius resulting in malunion or retardation of radial growth. 2

Related Anatomy

  • Ulna
  • Ulnar styloid
  • TFCC
  • Distal radioulnar joint (DRUJ)
  • Lunate
  • Triquetrum
  • Radius

Incidence and Related Conditions

  • A common cause of ulnar-sided wrist pain
  • Occurs along with lesions in the TFCC and the triquetrolunate ligaments

Differential Diagnosis

  • TFCC tear
  • Lunotriquetral ligament tear
  • Ulnar styloid impingement syndrome
  • Distal radioulnar joint (DRUJ) arthrosis
ICD-10 Codes

ULNAR CARPAL ABUTMENT

Diagnostic Guide Name

ULNAR CARPAL ABUTMENT

ICD 10 Diagnosis, Single Code, Left Code, Right Code and Bilateral Code

DIAGNOSIS SINGLE CODE ONLY LEFT RIGHT BILATERAL (If Available)
ULNOCARPAL ABUTMENT (WRIST DERANGEMENT) NEC   M24.832 M24.831  

ICD-10 Reference

Reproduced from the International statistical classification of diseases and related health problems, 10th revision, Fifth edition, 2016. Geneva, World Health Organization, 2016 https://apps.who.int/iris/handle/10665/246208

Clinical Presentation Photos and Related Diagrams
Clinical Presentation
  • Left wrist of a 48 y.o. right handed male with severe ulnar impaction syndrome. Note mild prominence of distal ulna (arrow). Patient also had marked tenderness in this area.
    Left wrist of a 48 y.o. right handed male with severe ulnar impaction syndrome. Note mild prominence of distal ulna (arrow). Patient also had marked tenderness in this area.
Pathoanatomy Photos and Related Diagrams
Measuring Ulnar Variance
  • When the distal radius and distal ulna are equal in length at the distal radioulnar joint, the ulnar variance is neutral. In this X-ray the ulnar variance is being measured with the method of perpendiculars (ref 14). The forearm is in neutral rotation, wrist at neutral deviation and flexion/extension, and the elbow at 90 degrees of flexion. The X-ray beam is at a zero degree angle of incidence for this PA view. (ref 15).
    When the distal radius and distal ulna are equal in length at the distal radioulnar joint, the ulnar variance is neutral. In this X-ray the ulnar variance is being measured with the method of perpendiculars (ref 14). The forearm is in neutral rotation, wrist at neutral deviation and flexion/extension, and the elbow at 90 degrees of flexion. The X-ray beam is at a zero degree angle of incidence for this PA view. (ref 15).
  • In this X-ray the negative ulnar variance (arrow) in millimeters (mm) is being measured with the method of perpendiculars (ref 14). The forearm is in neutral rotation, wrist at neutral deviation and flexion/extension, and the elbow at 90 degrees of flexion. The PA X-ray has been taken with the beam at a zero degree angle of incidence. (ref 15)
    In this X-ray the negative ulnar variance (arrow) in millimeters (mm) is being measured with the method of perpendiculars (ref 14). The forearm is in neutral rotation, wrist at neutral deviation and flexion/extension, and the elbow at 90 degrees of flexion. The PA X-ray has been taken with the beam at a zero degree angle of incidence. (ref 15)
  • In this X-ray the positive ulnar variance (arrow) in millimeters (mm) is being measured with the method of perpendiculars (ref 14). The forearm is in neutral rotation, wrist at neutral deviation and flexion/extension, and the elbow at 90 degrees of flexion. The PA X-ray has been taken with the beam at a zero degree angle of incidence. (ref 15)
    In this X-ray the positive ulnar variance (arrow) in millimeters (mm) is being measured with the method of perpendiculars (ref 14). The forearm is in neutral rotation, wrist at neutral deviation and flexion/extension, and the elbow at 90 degrees of flexion. The PA X-ray has been taken with the beam at a zero degree angle of incidence. (ref 15)
Symptoms
History of childhood wrist injury
History of participation in gymnastics
Ulnar-sided wrist pain especially with power grip and ulnar deviation
Limited range of motion in the wrist
Weakened grip
Typical History

A 16 y.o. right handed female gymnast presented with insidious onset of ulnar-sided wrist pain. She has no history of a specific wrist injury.  She used wrist guards but her pain continued to interfere with her performance.  Recently she has to suspend her routine work-outs because of her increasing right ulnar wrist pain. She consulted with a local hand surgeon. An X-ray of the right wrist showed marked positive ulnar variance and a small cystic change in the ulnar corner of the lunate. An MRI showed marked thinning of the central portion of the TFCC.  Wrist arthroscopy and ulnar shortening were recommend by the patient's surgeon.

Positive Tests, Exams or Signs
Work-up Options
Images (X-Ray, MRI, etc.)
X-ray Findings in Ulnar Impaction Syndrome
  • Significant ulnar positive variance right wrist in a gymnast
    Significant ulnar positive variance right wrist in a gymnast
  • In this patient there is only slight positive ulnar variance (see insert & arrow) but variance increases significantly with grip (large image).
    In this patient there is only slight positive ulnar variance (see insert & arrow) but variance increases significantly with grip (large image).
  • Marked positive ulnar variance with degenerative changes in the ulnocarpal joint but no symptomatic OA in DRUJ.
    Marked positive ulnar variance with degenerative changes in the ulnocarpal joint but no symptomatic OA in DRUJ.
Treatment Options
Treatment Goals
  • Alleviate the patient's symptoms
  • Decrease or eliminate wrist pain
  • Improve and maintain normal hand/wrist function
Conservative
  • Immobilization of the symptomatic wrist
  • Non-steroidal anti-inflammatory drugs (NSAIDs)
  • Avoidance of ulnar deviation and power grip
  • Activity modification e.g. discontinue tumbling
Operative
  • Ulnar shortening osteotomy (osteoplasty) is currently the most common procedure used for the operative treatment of ulnar impaction syndrome.  During an ulnar shortening osteotomy an appropriately sized diaphyseal cross sectional piece of the ulna is removed. The osteotomy is then internally fixed with a plate and screws. One advantage of the ulnar shortening osteotomy is the extra-articular location of the osteotomy.  This procedure is usually done in conjunction with wrist arthroscopy which is used to evaluate the cartilage surfaces and the TFCC.  Also wrist arthroscopy allows simultaneous synovectomy if indicated and TFCC debridement.2,12,13
  • The second surgical option for ulnar impaction syndrome is the wafer resection of the distal ulna (either open3 or arthroscopic4).  In this procedure the distal 2–4mm of the ulnar head is resected while preserving the styloid process and associated ligamentous attachments.
  • The third surgical option for ulnar impaction syndrome is the metaphyseal ulnar shortening osteotomy(without hardware5 or with screw fixation either open6, 7 or arthroscopic8).  This osteotomy is made in the distal metaphysis of the ulna, preserving the articular cartilage and ligamentous structures of the ulnar head while still shortening the ulna.9
Treatment Photos and Diagrams
Surgical Treatment of Ulnar Impaction Syndrome (AO Free Hand Technique)
  • Significant ulnar positive variance right wrist
    Significant ulnar positive variance right wrist
  • Standard AO plate being placed on ulnar to check positioning.
    Standard AO plate being placed on ulnar to check positioning.
  • First cut in the ulna has been made 90% through the ulna. Extra saw blade held in this first partial cut to act as a guide for second free hand transverse osteotomy cut. Line etched along longitudinal axis to guide normal rotational alignment after osteotomies completed and ORIF completed.
    First cut in the ulna has been made 90% through the ulna. Extra saw blade held in this first partial cut to act as a guide for second free hand transverse osteotomy cut. Line etched along longitudinal axis to guide normal rotational alignment after osteotomies completed and ORIF completed.
  • Second cut being made. Note extra blade (guide for plate of second cut) being held in the first cut by a hemostat. Arrow on piece of bone to be removed. Saw removes 1mm of bone. Piece 2mm wide so two cuts and removed bone will shorten ulna 4mm.
    Second cut being made. Note extra blade (guide for plate of second cut) being held in the first cut by a hemostat. Arrow on piece of bone to be removed. Saw removes 1mm of bone. Piece 2mm wide so two cuts and removed bone will shorten ulna 4mm.
  • Compression plate held in place with bone clamps prior to screw fixation and osteotomy compression. Arrow at osteotomy site.
    Compression plate held in place with bone clamps prior to screw fixation and osteotomy compression. Arrow at osteotomy site.
  • Postoperative AP & Lateral X-rays after shortening and internal fixation. Note 1mm of negative ulnar variance (arrow) after shortening osteoplasty.
    Postoperative AP & Lateral X-rays after shortening and internal fixation. Note 1mm of negative ulnar variance (arrow) after shortening osteoplasty.
Surgical Treatment of Ulnar Impaction Syndrome (Ulnar Osteotomy Technique with Shortening Device and Guides)
  • Right ulnar shaft exposed for ulnar shortening. Keep periosteal (arrow) stripping to a minimum to maintain blood supply to the bone.
    Right ulnar shaft exposed for ulnar shortening. Keep periosteal (arrow) stripping to a minimum to maintain blood supply to the bone.
  • Plate attached proximally with 3 cortical screws and distally with one screw distally in the slotted hole (arrow). Oblique screw guide held in place with short and long K-wires.
    Plate attached proximally with 3 cortical screws and distally with one screw distally in the slotted hole (arrow). Oblique screw guide held in place with short and long K-wires.
  • The "A" oblique osteotomy guide(arrow) is held in place with a K-wire. The "A" guide determines the amount of bone resection. Apply saline irrigation while cutting osteotomies to minimize heat damage to the ulna.
    The "A" oblique osteotomy guide(arrow) is held in place with a K-wire. The "A" guide determines the amount of bone resection. Apply saline irrigation while cutting osteotomies to minimize heat damage to the ulna.
  • Both oblique parallel osteotomies (double arrows) has been completed. Insert shows bone being removed (single arrow).
    Both oblique parallel osteotomies (double arrows) has been completed. Insert shows bone being removed (single arrow).
  • Defect in ulna (arrow) shown prior to compression. The compression clamp is attached to the plate and to an extra temporary K-wire.
    Defect in ulna (arrow) shown prior to compression. The compression clamp is attached to the plate and to an extra temporary K-wire.
  • Osteotomy (1) tightly compressed. Note the screw in the slotted hole has moved proximally towards the osteotomy as the osteotomy was closed.
    Osteotomy (1) tightly compressed. Note the screw in the slotted hole has moved proximally towards the osteotomy as the osteotomy was closed.
  • Completed ulnar shortening osteoplasty. Note the neutral variance (arrow).
    Completed ulnar shortening osteoplasty. Note the neutral variance (arrow).
CPT Codes for Treatment Options

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Common Procedure Name
Ulnar or radial shortening osteoplasty
CPT Description
Osteoplasty radius or ulna shortening
CPT Code Number
25390
CPT Code References

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Complications
  • The frequency of complications can vary by surgical technique. In a systematic review of 16 studies, the overall complication rates for ulnar shortening osteotomy, wafer resection, and arthroscopic wafer resection were 30%, 9%, and 21% respectively.9
  • All ulnar shortening techniques may result in degenerative changes to the DRUJ, particularly when the sigmoid notch is reverse oblique such that shortening results in DRUJ compression.
  • The most common complication of diaphyseal ulnar shortening osteotomy is hardware removal due to irritation from the bone-plate, required in 39% (11/28) cases in a recent report.10
  • Surgical site infection which is very rare
  • Nonunion after ulnar shortening osteotomy occurred in 18% (5/28) patients in a recent report,10 although a previous systematic review had found non-union to occur in only 2%.9
Outcomes
  • In a recent systematic review of 11 studies, 82% of patients reported good/excellent results after USO (N=274).11
  • Outcomes after the open wafer procedure were reported as good/excellent in 100% (12/12) patients at 1 year.3
  • In patients undergoing distal metaphyseal shortening osteotomy (without hardware), 86% (6/7) reported satisfactory results.5
Video
Marked clicking and pain in a severe case of ulnar impaction syndrome.
Key Educational Points
  • In ulnar impaction syndrome, the ulnocarpal stress test produces pain during forearm rotation and ulnar deviation.12 
  • Postive ulnar variance occurs in the ulnar impaction syndrome because the ulna is longer than the radius at the junction of radiocarpal joint and the distal radioulnar joint. 
  • Ulnar variance is best measured on a neutral rotation posterioranterior X-ray taken with the wrist deviation also in neutral.12 
  • Adolescent patients may develop ulnar impaction syndrome.  The most accurate assessment of ulnar variance can be done after the epiphyseal plates of the distal ulna and radius are closed.
  • Surgery is contraindicated by established DRUJ arthritis and dorsal dislocation of the DRUJ.2 
References

Cited

  1. Palmer AK, Glisson RR, Werner FW. Ulnar variance determination. J Hand Surg Am 1982;7(4):376-79. PMID: 7119397
  2. Sachar K. Ulnar-sided wrist pain: Evaluation and treatment of triangular fibrocartilage complex tears, ulnocarpal impaction syndrome, and lunotriquetral ligament tears. J Hand Surg Am 2012;37(7):1489-1500. PMID: 22721461
  3. Feldon P, Terrono AL, Belsky MR. Wafer distal ulna resection for triangular fibrocartilage tears and/or ulna impaction syndrome. J Hand Surg Am 1992;17(4):731-37. PMID: 1629557
  4. Wnorowski DC, Palmer AK, Werner FW, Fortino MD. Anatomic and biomechanical analysis of the arthroscopic wafer procedure. Arthroscopy 1992;8(2):204-12. PMID: 1637434
  5. Barry JA, Macksoud WS. Cartilage-retaining wafer resection osteotomy of the distal ulna. Clin Orthop Relat Res 2008;466(2):396-401. PMID: 18196423
  6. Slade JF,3rd, Gillon TJ. Osteochondral shortening osteotomy for the treatment of ulnar impaction syndrome: A new technique. Tech Hand Up Extrem Surg 2007;11(1):74-82. PMID: 17536528
  7. Hammert WC, Williams RB, Greenberg JA. Distal metaphyseal ulnar-shortening osteotomy: Surgical technique. J Hand Surg Am 2012;37(5):1071-7. PMID: 22541156
  8. Yin HW, Qiu YQ, Shen YD, et al. Arthroscopic distal metaphyseal ulnar shortening osteotomy for ulnar impaction syndrome: A different technique. J Hand Surg Am 2013;38(11):2257-62. PMID: 24206993
  9. Katz DI, Seiler JG,3rd, Bond TC. The treatment of ulnar impaction syndrome: A systematic review of the literature. J Surg Orthop Adv 2010;19(4):218-22. PMID: 21244809
  10. Doherty C, Gan BS, Grewal R. Ulnar shortening osteotomy for ulnar impaction syndrome. J Wrist Surg 2014;3(2):85-90. PMID: 25032074
  11. Smet LD, Vandenberghe L, Degreef I. Ulnar impaction syndrome: Ulnar shortening vs. arthroscopic wafer procedure. J Wrist Surg 2014;3(2):98-100. PMID: 25032075
  12. McBeath R, Katolik LI, Shin EK. Ulnar shortening osteotomy for ulnar impaction syndrome. J Hand Surg Am. 2013:38A:379-381.
  13. Cha SM, Shin HD, Kim KC, Park E. Ulnar shortening for adolescent ulnar impaction syndrome: radiological and clinical outcomes. J Hand Surg Am. 2012; 37A: 2462-2467.
  14. Steyers CM, Blair WF.  Measuring ulnar variance: A comparison of techniques. J Hand Surg Am. 1989; 14A: 607-612.
  15. Epner RA, Bowers WH, Guiford WB. Ulnar variance - the effect of wrist positioning and roentgen filming tachnique. J Hand Surg Am. 1982; 7: 298-305.

New Articles (within the past 3 years)

  1. Doherty C, Gan BS, Grewal R. Ulnar shortening osteotomy for ulnar impaction syndrome. J Wrist Surg 2014;3(2):85-90. PMID: 25032074
  2. Hammert WC, Williams RB, Greenberg JA. Distal metaphyseal ulnar-shortening osteotomy: Surgical technique. J Hand Surg Am 2012;37(5):1071-77. PMID: 22541156

Reviews

  1. Katz DI, Seiler JG,3rd, Bond TC. The treatment of ulnar impaction syndrome: A systematic review of the literature. J Surg Orthop Adv 2010;19(4):218-22. PMID: 21244809
  2. Sachar K. Ulnar-sided wrist pain: Evaluation and treatment of triangular fibrocartilage complex tears, ulnocarpal impaction syndrome, and lunotriquetral ligament tears. J Hand Surg Am 2012;37(7):1489-1500. PMID: 22721461
  3. Smet LD, Vandenberghe L, Degreef I. Ulnar impaction syndrome: Ulnar shortening vs. arthroscopic wafer procedure. J Wrist Surg 2014;3(2):98-100. PMID: 25032075

Classics

  1. Feldon P, Terrono AL, Belsky MR. Wafer distal ulna resection for triangular fibrocartilage tears and/or ulna impaction syndrome. J Hand Surg Am. 1992;17(4):731-737 PMID: 1629557
  2. Friedman SL, Palmer AK. The ulnar impaction syndrome. Hand Clin 1991;7(2):295-310. PMID: 1880164
  3. Palmer AK, Glisson RR, Werner FW. Ulnar variance determination. J Hand Surg Am 1982;7(4):376-9. PMID: 7119397
  4. Epner RA, Bowers WH, Guilford WB. Ulnar variance - the  effect of wrist positioning and roentgen filming technique. J Hand Surg Am. 1982; 7:298-305.