Ulnar Impaction Syndrome

Definition/Description

Ulnar impingement syndrome, also known as ulnocarpal abutment syndrome, is a common cause of ulnar wrist pain. [1] [2] This is a degenerative disorder in which the head of the ulna abuts the triangular fibrocartilage complex (TFCC) and the ulnar carpal bone. [3] [4] This abutment results in an increased load TFCC spanning the ulnar head and ulnar carpal bone, followed by chondromalacia degeneration of TFCC of the involved bony structures (ulna and carpal bones, especially the lunate), and destruction of the ligaments of the three lunates. [2][5]

Epidemiology/Etiology

The most common predisposing factor for ulnar impingement syndrome (UIS) is a positive ulnar variance—that is, an increase in the length of the ulna relative to the radius. Positive ulnar variance has been found to be inversely proportional to TFCC thickness; thus in positive ulnar variance of the wrist, the TFCC is stretched Thin and large biomechanical forces, especially rotational forces, can affect joints. This positive variance can come from [2][3][6][7]:

• Congenital positioning of the articular surface of the ulna more distal than the articular surface of the radius
• Acquired radius shortening secondary to trauma – eg radial malunion following distal radius fracture Essex-Lopresti injury Proximal radius displacement after radial head resection or premature epiphyseal closure of the radius
• Excessive changes in ulna dynamics during forearm pronation and grasping greater than normal distal motion of the ulna

Wrists without positive ulnar changes but considered ulna-neutral or negative ulna may also acquire UIS because changes increase during functional activities, especially those that include forearm pronation and grasping. [6][8][9] When the ulnar variance of the wrist increases Ulnar negative or neutral (thus having thicker TFCC) ulnocarpal loads are also increased. [1] Thus, although UIS is most common in persons with positive ulnar wrists, it can also occur in negative or neutral wrists. [9]

Characteristics/Clinical Presentation

Ulnar impingement syndrome is insidious and progressive, so patients may be asymptomatic or severely symptomatic while undergoing physical therapy. Common symptoms are: Pain Occasional edema Decreased wrist mobility Decreased forearm rotation and tenderness Dorsal palpation is just distal to the ulnar head, just volar to the ulnar styloid process. These symptoms are usually exacerbated by a firm grip of the forearm in pronation and ulnar deviation. [1]

Differential Diagnosis

Lesions on the ulnar side of the wrist are often very similar in terms of injury and pain pattern. Thus, in cases of pain on the ulnar side of the wrist, diagnostic imaging is usually required to confirm the diagnosis and should be considered after the history and clinical examination. [1][10][11][12]

Note: TFCC injuries often occur secondary to or in conjunction with ulnar impingement syndrome. [10]

DISORDERSIGNS & SYMPTOMSTESTSTFCC Injury – Ulnar Wrist Pain – Popping or Clicking – TFCC Compression Test – Piano Key Sign – Supination Pull Test – Palpation Lunate Trigonal Ligament (LTIL) Injury – Joint Tenderness – Reduced Joint Range of Motion – Mobility reduced Grip Strength – Painful Rattling of Radial and Ulnar Deviations – Ballottement Test – Shuck Test – Shear Test – Ulnar Snuff Bottle Test Arthritis – DRUJ – Pisotriquetral – Pain and Crepitus on Load – ROM Decreased – Grip Strength Decreased – Localized Pain – Grinding Test – Joint Palpation Wire – Poll Test – ROMDRUJ Instability – Forearm Rotational Pain – Grinding Test – Palpation of ECU Pathology – Pain Specific to ECU Tendon – ECU Subluxation – Palpation of ECU Tendon on Ulnar Head – Resistance Wrist Extension and Ulnar Deviation – Active Forearm Supination and Ulnar Deviation Fractures – Ulnar styloid-triquerum-hamate. – Tenderness and edema – Decreased ROM – Decreased wrist strength – Pain during movement – Palpation of bony landmarks – DRUJ stability (ulnar styloid process) – Instability of middle wrist with resistance to flexion of 5th finger (hamate) – Carpal dullness with ulnar deviation and pronation – ulnar wrist sagging – usually bilateral – carpal displacement test Kimberk’s disease – chronic wrist pain without trauma – dorsal lunate tenderness – reduced ROM – grip strength Descent – Arthritis (advanced) – Lunate palpation ulnar nerve entrapment – Paresthesias of 4th and 5th fingers – Intrinsic hand weakness – Tinel’s to Guyon’s canal – Symptoms History/pattern Unar artery thrombosis – Nocturnal pain – Pain with repetitive activities – Cold intolerance – Extreme tenderness at pathological site – Dependent redness or ulceration or 4th or 5th Fingertips – Excitation of sympathetic fibers of ulnar proper nerve – Allen test Dorsal ulnar cutaneous neuritis – Sensory changes in 4th and 5th fingers – Elbow pain or sensory changes and/or hand weakness suggest more proximal ulnar neuropathy . – Sensory examination – Palpation – Wartenburg’s sign (motor pathology) – Froment’s sign (motor pathology)

Outcome Measures

• DASH
• Gripping Rotary Impaction Test (GRIT)[6]

Examination

To diagnose ulnar impingement syndrome, a complete wrist examination must be completed. Diagnostic imaging should be performed to support the findings of the clinical examination. Physiotherapists should pay particular attention to the following points:

• Palpation[8][13]
  • Tenderness dorsal just away from ulnar head
  • Lunar styloid tenderness
  • Positive ulna change when static or dynamic
• Range of Motion[8][13][14]
  • Painful passive ulnar deviation and strong pronation
  • Reduce flexion-extension radial and ulnar deviation
• Strength[8][9][13]
  • Reduce Grip Strength Using a Dynamometer
• Ulnocarpal Stress Test[15]
  • Place wrist in maximum ulnar deviation
  • Apply axial load to wrist
  • Passively rotate the forearm through supination and pronation
  • + test = recurrence of patient’s pain NOTE – Test is sensitive to UIS but may be positive for other conditions such as LTIL lesions, TFCC lesions or solitary arthritis.
• Gripping Rotary Impaction Test (GRIT)[6]
  • Place arms side by side with elbows bent 90 degrees
  • Measure grip strength in 3 positions using a hand dynamometer: neutral fully supinated fully pronated
  • GRIT Ratio = (grip strength after turning) / (grip strength before turning)
    • A GRIT ratio greater than 1.0 indicates UIS

It may be necessary to examine the integrity of the TFCC, especially in patients with suspected chronic ulnar impingement syndrome, as degeneration of this structure is common. [7]

• Imaging – used to support physical examination findings
• • Radiograph[1][8][14][16]
    • Views:
      • Neutral rotation P-A radiograph with elbow flexed to 90°
      • Pronated grip P-A radiograph
        • May have subchondral sclerotic cystic changes or osteophyte formation
        • Positive ulnar variation is a hallmark of UIS
  • MRI[8][13][16]
    • Detect tears of TFCC and other soft tissue injuries
    • Detects decreased vascular congestion or anatomical abnormalities of the lunate and ulnar heads
  • Arthrography[8][16][17]
    • Currently considered the “gold standard” for detecting TFCC damage
    • Although recent studies have refuted this because of high false-negative rates, poor correlation between results and patient presentation, and MRI is more effective
  • Computed Tomography[7]
    • For determining pathology of the distal radioulnar joint
  • Arthroscopy[7]
    • Considered the “gold standard” for identifying bone lesions
  • Fluoroscopy[7]
    • For the evaluation of dye leakage due to TFCC damage

Criteria for ulnocarpal abutment syndrome [15]

1. Ulnocarpal pain distal to the ulnar head (dorsal and/or volar) with tenderness
2. Ulcerative or cystic lesion of the lunate lunate base and/or ulnar head on X-ray or low signal intensity of the lunate-ulnar base on MRI on T1-weighted images or degenerative lesions of TFCC on arthroscopic examination (Palmer class grade 2 lesion).

Medical Management

Surgery Options

Ulnar Shortening Osteotomy[3][18]

• Shorten the shaft of the ulna by 2-3mm, remove and secure with a tubular or standard compression plate
  • Indications: History of ulnar pain at the wrist, worsening rotation and ulnar deviation; positive ulnocarpal stress test and positive ulnar variation, with or without cystic changes
  • Contraindicated in patients with advanced distal radioulnar joint arthritis
• Baek et al showed significant improvement in idiopathic UIS:
  • Pre-Op modified Gartland & Werley 分數：24 wrist rated poor 7 fair
  • Postoperative modified G&W score: 24 excellent 5 good 1 fair 1 poor
  • Reduced distal radioulnar joint subluxation and resolution of degenerative cystic changes in the ulnar carpal bone
  • Reduced mean ulnar variance from +4.6 preoperatively to -.07 postoperatively
• Chun et al showed 100% binding within 6-8 weeks Excellent results at 72% on Gartland & Werley

Arthroscopic Wafer Procedure[19]

• If there is no evidence of lunotrigonal instability, minimal ulnar variance cystic changes of the carpus on radiograph and TFCC regression on MRI, it is indicated
• Contraindicated if ulnar variance is greater than +4mm
• TFCC debridement prior to 2.3mm distal ulna resection
• Good to excellent results 85-100%. Near full range of motion but no improvement in grip strength
• Patients with a history of distal radius fractures had significantly worse postoperative pain

Tomanino et al [9]

• Combined arthroscopic TFCC debridement and wafer resection.
• Complete remission of PN in 8 of 12 patients with 36% increase in grip strength

Feldon et al[20] 

• 69% Excellent and 31% Good results from the Open Wafer Program
• Longer postoperative immobilization and recovery time

 Bowers Procedure[21]

• Resection of the head of the ulnar joint leaves the shaft and styloid process intact
• If the TFCC is intact or able to be rebuilt, use

Darrach Procedure[21]

• Resection of ulnar head if reconstruction of TFCC is not possible

Sauve-Kapandji Procedure[21]

• Resection of the distal ulna and fusion of the ulnar head and radius with screws and/or pins
• Intended for use in arthritic RU joints to help patients maintain TFCC integrity and improve forearm rotation

UIS wrist wafer before and after images. Used with permission of the authors (Meftah et al 2010)

Complications

• Scar infection Injury to the dorsal sensory branch of the ulnar nerve Numbness of fingers 10 hours after surgery Delayed or non-union reflex Sympathetic dystrophy ECU sheath tendonitis [3][19][22]

 Pre-op (~3 months)[3][19]

• Brace/Splint
• NSAIDS 
• Occupational/Physical therapy
• Cortisone injections
• Activity modifications

Post-op:[19][22][23]

• 1-2 weeks immobilized in long arm splint; stitches removed 10-14 days
• Referred to OT/PT
• Removable long arm splint 4-8 weeks
• Hand elevation to prevent swelling
• X-rays at 6 weeks to make sure bones are healing
• 12-16 weeks before starting heavy activity
• Smoking adversely affects healing time of osteotomized ulna

Physical Therapy Management

Sugar Splint. Image used with permission from SAM Medical

Conservative management should be attempted prior to surgery, including immobilization with 6-12 weeks of NSAIDs, corticosteroid injections and limitation of exacerbating movements such as pronated grasp and ulnar deviation. Lack of improvement from conservative management suggests Surgery[1][6][7]

UIS may be associated with grade 2 TFCC injuries and cause instability of the distal radioulnar joint (DRUJ). [7][16][24][25] Therapists should use an injury-based approach to postoperative care, keeping in mind that postoperative patients have had an ulnar resection or removal of the Defects in the ulnar shaft portion caused by fixation, may also have a compromise of TFCC with DRUJ instability.

Examples of postoperative protocols [1][22][24][26]

Time Frame Target Bracing/Splitting Physical Medications TherEx Manual Technique 0 – 2 weeks – Control Pain and Swelling – Protect Surgical Site – Maintain ROM of Unaffected Joint – Sugar Clamp Splint – Long Arm Cast – Ice – Pain Relief – NWB – Elevated Edema – Shoulder ROM – Digital ROM2 – 6 weeks – Protect surgical site – Maintain ROM in unaffected joints – Increase elbow and wrist ROM – Scar treatment – Removable elbow hinge splint or wrist lift brace – See above – As needed – Limit wrist and forearm ROM External Splint – Stretches Elbow and Wrist – Avoid weight bearing pronation and supination – continue shoulder and digital ROM – soft tissue massage 6 – 8 weeks – increase elbow and wrist ROM – increase UE strength – scar management – removable splint worn at night – see above – as needed – Complete AROM at Elbow and Wrist – Elbow and Wrist Stretch – Isometric Elbow Flexion/Abduction and Sit Ups/Pronation – Soft Tissue Massage 12 – 16 weeks – Address remaining ROM and strength impairments – Splints can still be worn at night – See above – As per Required – Complete AROM for Elbow and Wrist – UE Strength Training – Soft Tissue Massage – Elbow Forearm and Wrist Mobility*

*If the joint to be moved is considered stable.

ROM exercises should be performed with low loads and high repetitions within pain limits to promote cartilage repair.

Full union is expected 3 months after ulnar shortening osteotomy. [1]

Expect return to full activity 6 months after ulnar shortening osteotomy and 8-12 weeks after wafer resection. [1]

Example Exercises

Clinical Bottom Line

Ulnar impingement syndrome is one of many possible causes of ulnar wrist pain and requires several special tests and imaging studies to confirm the diagnosis. If conservative treatment proves ineffective, medical management is required and physical therapy should be followed to address the resulting problems Impairment of upper extremity exercise strength and joint range of motion.