What Is Midcarpal Instability (Wrist Instability)?

Mid-Carpal Instability: www.wheelessonline.com/ortho/mid_carpal_instability & wristinstability.multiply.com/journal/item/3

*patients may note wrist clicking and pain while lifting heavy objects;

*grasping in supination may provoke symptoms;

*symptoms may include tenderness over lunocapitate and triquetrohamate joints;

*the later is thought to be the more affected joint;

*painful audible snap often results from active ulnar deviation w/ forearm pronation;

*the flexion subluxation of the proximal carpal row causes the reduction clunk (proximal row extension) as the wrist moves into ulnar deviation;

*some loss of palmar flexion is usually present;

*grip strength can be decreased by as much as 50%;

*ref: Quantitative assessment of the midcarpal shift test.<br><br>Post edited by: Scott_1984, at: 2009/02/08 09:54

Ulnar midcarpal instability-clinical and laboratory analysis (September 1981): lib.bioinfo.pl/pmid:7276484

Patients with ulnar midcarpal instability have a characteristic pattern of clinical signs and symptoms related to the midcarpal joint.

The usual presenting complaint is a painful wrist click which can be reproduced by ulnar deviation, axial compression, and pronation of the wrist.

Routine x-rays are usually normal, but cinefluoroscopy reveals sudden dissociation between the proximal and distal carpal rows resulting in a dorsiflexion collapse deformity.

In six of our patients, conservative therapy sufficed to relieve symptoms.

Four other patients required surgical stabilization.

We close to stabilize the triquetrohamate joint because it was a relatively easy procedure and eliminated instability in most instances.

Laboratory studies aided in understanding the pathomechanics of midcarpal instability, which consisted of dorsal subluxation of the capitate and hamate on the lunate and triquetrum.

We believe that midcarpal instability is not a rare condition but may often be confused clinically with more common carpal dissociations.

A Clinical Analysis of Pathomechanics of Extrinsic Midcarpal Instability (1999): sciencelinks.jp/j-east/article/200012/000020001200A0235739.php

Abstract: sciencelinks.jp/j-east/article/200012/000020001200A0235739.php

There has recently been increasing interest and recognition regarding the midcarpal instability (MCI).

MCI is classified into three types, that is palmar MCI, dorsal MCI, and extrinsic MCI (EMCI) with a Z deformity of the carpus after Colles' fracture. The purpose of this study is to clarify the pathomechanics of EMCI clinically.

In 3 cases with clinical findings of EMCI we observed movement of the carpus by cineradiography, comparing with normal wrist joints and those with malunited distal radius fracture.

The range of motion of the wrist is almost normal after Colles' fracture with EMCI.

The average age of patients with EMCI was younger than that of malunited fractures without wrist instability.

There was no relationship between the occurrence of EMCI and severity of malalignment of the distal radius.

In EMCI the cineradiography of the lateral view in maximum ulnar deviation showed that the lunata rapidly dorsiflexes and shifts in the palmar direction considerably, and the capitate simultaneously shifts in the dorsal direction.

On the other hand, the motion of the lunate was small in malunited cases without wrist instability.

These clinical findings suggest the rupture and laxity of the palmar carpal ligaments in EMCI.

We concluded that the pathomechanics of EMCI are the major change of the distal radius with severe dorsal tilt and the dorsiflexed position of the lunate with palmar translation in ulnar deviation.

In this position, the capitate translates dorsally for the ruptured and lengthened palmar ligament.

The axis of the capitate is not colinear with the lunate, and sudden clicks or painful subluxation occurs. (author abst.)

Ulnar-Sided Wrist Pain: www.emedicine.com/orthoped/topic619.htm

INTRODUCTION: www.emedicine.com/orthoped/topic619.htm

Wrist pain often proves to be a challenging presenting complaint.

Determining the cause of ulnar-sided wrist pain is difficult, largely because of the complexity of the anatomic and biomechanical properties of the ulnar wrist.

The objectives of this article are to provide an overview of the most common problems encountered in the diagnosis of ulnar-sided wrist pain and to review anatomy, diagnostic modalities, clinical presentation, and various treatments available.

Over the last several years, great advances have occurred in imaging techniques.

Although these imaging techniques are often invaluable, at times they are expensive and unnecessary.

The majority of diagnoses involving ulnar wrist pain may be established with detailed history taking, thorough physical examination, and standard radiography.

When a diagnosis cannot be established by using the standard methods, more advanced diagnostic modalities should be considered.

For excellent patient education resources, visit eMedicine's Hand, Wrist, Elbow, and Shoulder Center: www.emedicinehealth.com/script/main/art.asp?articlekey=60053

Also, see eMedicine's patient education article Wrist Injury: www.emedicinehealth.com/wrist_injury/article_em.htm

ABSTRACT: www.orthosupersite.com/default.asp?page=view&rid=2392

The evaluation of chronic wrist pain can be a diagnostic dilemma.

Lidocaine injections combined with corticosteroids often are used for therapeutic and diagnostic purposes.

This study determined whether a midcarpal injection of lidocaine could serve as a diagnostic tool in patients with chronic wrist pain.

Specifically, the relationship of pain relief from the injection and improvement of grip strength were compared to intracarpal pathology as confirmed by wrist arthroscopy.

Forty-five patients with chronic wrist pain underwent a midcarpal injection of lidocaine with or without corticosteroids.

Improvement of pain and improvement of grip strength were determined. Each patient subsequently underwent a radiocarpal and midcarpal arthroscopy, and the pathologic findings of arthroscopy were compared to the improvement of pain and grip strength.

These data were compared to a cohort of six volunteers without history of wrist pain or trauma who underwent midcarpal injection of lidocaine.

Statistical analysis was performed using Receiver-Operator-Characteristic analysis.

The average age of patients with chronic pain was 30.3 years, with an average of 9.8 months of wrist pain.

The ultimate diagnoses included carpal dissociative instability (n=35), nondissociative instability (n=2), complex instability of the carpus (n=7), extensor carpi ulnaris tendinitis (n=3), and deQuervain's tenosynovitis (n=1).

After lidocaine injection, the normal cohort had a mean loss of 2 kg (25.3%) (P=.02) in grip strength whereas the experimental cohort had a mean improvement in grip strength of 5.73 kg (34.4%).

Improvement of pain after injection did not correlate with pathologic arthroscopic findings (P=.92).

Improvement in grip strength after midcarpal lidocaine injection of 6 kg or 28% had a 73% sensitivity and 70% specificity (P=.02) of having intracarpal pathology at arthroscopy.

Of the chronic wrist pain patients, only 4 had a normal arthroscopy, and the remainder had at least 1 area of significant pathology attributing to their pain.

A midcarpal injection of lidocaine serves as an effective diagnostic tool in the evaluation of patients with chronic wrist pain.

A 28% improvement of grip with or without pain relief is highly correlated with intracarpal pathology. www.orthosupersite.com/default.asp?page=view&rid=2392

Quantitative assessment of the midcarpal shift test:

The subjective, clinical midcarpal shift test was compared with a quantitative measurement of carpal volar/dorsal translation versus ulnar deviation using a mechanical testing system.

Testing was performed on 19 healthy volunteers (mean age, 33 years) and 3 patients (four wrists; mean age, 23 years) who had been diagnosed with ulnar midcarpal instability, a nondissociative form of carpal instability.

During physical examination, each subject's wrist was graded I to V using the previously described classification of the degree of laxity and clunk observed with the midcarpal shift test.

Each subject was also evaluated using a quantitative mechanical testing system that simulates the subjective clinical test.

The testing system measures displacement of the distal carpal row, more specifically, the capitate, as the wrist is moved from neutral to ulnar deviation under a constant axial load of 44 N directed volarly at the head of the capitate.

Reflective markers were attached to the skin above the proximal and distal ends of the third metacarpal and at the point where the 44-N load was applied to the carpus.

Motion of the markers was used to calculate ulnar deviation and dorsal/volar translation of the carpus.

The maximum slope of the carpal translation versus ulnar deviation curve was measured for each subject and compared with the results of the clinical midcarpal shift test.

Higher maximum slopes were seen in subjects with the higher grades of carpal laxity.

There were also differences with regard to the point at which the clunk occurred; the higher the clinical grade of laxity, the greater the ulnar deviation of the wrist at the point at which the clunk was observed.

These differences were not significant, however.

These data confirm the validity of the clinical test and establish its usefulness as a diagnostic indicator of midcarpal nondissociative carpal instability.

The mechanized test also may be useful as a biomechanical marker, enabling the results of ligament sectioning to be effectively compared with defined clinical laxity.

Watson's Test: en.wikipedia.org/wiki/Watson%27s_test

Watson's test is a diagnostic test of the wrist for scapho-lunate instability.

To perform the test, the examiner grasps the wrist with their thumb over the patient's scaphoid tuberosity.

The patient's wrist is then moved from ulnar to radial deviation.

The examiner will feel a significant 'clunk' and the patient will experience pain (even on the normal side). For completeness, the test must be performed to both wrists.

If the scapho-lunate ligament is disrupted, the scaphoid will tend to turn down and the lunate to turn up.

This procedure reproduces the subluxation: en.wikipedia.org/wiki/Subluxation

Carpal Instability in the Weight-Bearing Upper Extremity

The prevalence of carpal instability in a paraplegic population was investigated to establish an association between chronic repetitive stress on the wrist and the development of such instability.

Nine of 162 paraplegic patients had static carpal instability and no history of an acute injury of the wrist.

The predominant pattern of instability, found in eleven wrists (six patients), was non-dissociative volar intercalated segmental instability.

The prevalence of carpal instability increased with the duration of weight-bearing on the upper extremity.

Eighteen per cent of the patients in whom the spinal cord injury had occurred more than twenty years before the study had carpal instability.

Carpal instability in these weight-bearing upper extremities and the increase in its prevalence with the duration of the forces across the wrist demonstrate an association between chronic repetitive stress on the wrist and carpal instability.

In conclusion, the present study of a paraplegic population demonstrated an association between carpal instability and chronic repetitive stress on the wrist.

Static carpal instability was found in 6 per cent of our entire study population and in 18 per cent of the patients who had had the spinal cord injury for more than twenty years.

This increase in the prevalence with the duration
of stress on the wrist suggests chronic repetitive stress as an etiology of carpal instability.

The predominant pattern of carpal instability was non-dissociative volar intercalated segmental instability.<br><br>Post edited by: Scott_1984, at: 2009/02/08 10:01

ARTHROSCOPIC CAPSULAR SHRINKAGE FOR MIDCARPAL INSTABILITY OF THE WRIST: proceedings.jbjs.org.uk/cgi/content/abstract/85-B/SUPP_II/177-c

This prospective study evaluated our results of arthroscopic electrothermal capsular shrinkage intrinsic (palmar) for midcarpal instability.

This method of treatment has not been described in the wrist in current literature.

Following clinical and video fluoroscopic diagnosis arthroscopy of the wrist and capsular shrinkage was performed on five patients.

A radiofrequency probe was mainly used on the ulnar arm of the volar arcuate ligament and the dorsal capsule of the radiocarpal joint.

One patient was lost to follow up. At a mean follow up of 11 months the results were: one excellent, two good and one fair using the Green and O’Brien wrist scoring system (Table1).

The average range of motion was 95 percent of the opposite wrist.

We concluded that arthroscopic radiofrequency capsular shrinkage is an effective, minimally invasive method of treatment for intrinsic midcarpal instability.

&amp;

Thermal Capsulorrhaphy for Midcarpal Instability: Meeting/Minutes of meeting held in November 2006 for THE BRITISH SOCIETY FOR SURGERY OF THE HAND (The British Hand Club) AUTUMN MEETING on 02nd &amp; 03rd of November 2006: (Page: 47) (Journal Attached): wristinstability.multiply.com/notes/item/6 & msngroup.aimoo.com/PalmarMidcarpalInstabilityPMCIRSD
Discussion: 15:38 Thermal Capsulorrhaphy for Midcarpal Instability:

Mr W T M Mason, Mr D Hargreaves (Southampton):

Introduction: Midcarpal instability is an uncommon but troublesome problem. For those in whom conservative measures fail, open ligament reconstruction or fusions have been described. We prospectively studied seventeen wrists in fourteen patients who underwent arthroscopic thermal capsulorrhaphy for midcarpal instability.

Methods: All patients were assessed clinically, by fluoroscopy and arthroscopy to confirm the diagnosis. Wrist arthroscopy with four portals was performed and monopolar radiofrequency thermal capsulorrhaphy was performed using a 2.3mm probe.

Results: 100% follow-up was achieved at a a mean of 42 months. Symptoms of instability were resolved completely in four wrists and almost completely in the remaining thirteen. The patients’ subjective overall assessment of the wrist was “much better” in twelve wrists, “better” for two wrists and “worse” for three wrists. These three cases had persistent pain despite the improvement in stability.

The cause of the pain was unrelated to the procedure or the initial pathology.

All patients were satisfied with the outcome and would undergo the same procedure again. Functional improvement was confirmed by an improvement in the mean DASH score from 38.3% pre-operatively to 17.0% at final follow-up. Mean wrist flexion and extension decreased by 25% and 17% respectively. There were no significant complications.

Conclusions: Thermal capsulorrhaphy greatly reduces symptoms of instability in patients with midcarpal instability. Longer follow-up is planned to observe whether these encouraging mid-term results deteriorate over time, as has been witnessed in the shoulder.<br><br>Post edited by: Scott_1984, at: 2009/02/08 09:55

A Slide Show Of Information, Surgeries, Therapiesa, &amp; More, On Carpal Instability: www.slideshare.net/hoc/carpal-instability

Palmar midcarpal instability: www.emedicine.com/orthoped/topic619.htm

Various authors have called palmar midcarpal instability (PMCI) by many names, including ulnar midcarpal instability, capitolunate instability pattern, ulnocarpal instability, and midcarpal instability. The most likely etiology in patients presenting with a painful midcarpal clunk is dysfunction of key ligaments that causes a loss of normal joint reactive forces between the proximal and distal rows. These ligaments include the arcuate, triquetrohamate, and capitolunate ligaments volarly and/or the radiotriquetral ligament dorsally.

In a normal wrist with ulnar deviation, the distal row translates from volar to dorsal as the proximal row rotates from flexion to extension. With laxity, attenuation, or traumatic disruption of these ligaments, the coupled rotation of the carpus is no longer present. Instead, the proximal row stays flexed, and the distal row remains excessively volarly translated until the extreme of ulnar deviation is reached, causing the proximal row to abruptly snap back into extension and the distal row to reduce (translate dorsally). The diagnosis is frequently based on the history and radiographic studies, in addition to the results of physical examination and midcarpal shift testing.

Patients present with painful clunking that occurs with ulnar deviation and pronation of the wrist. A history of trauma may or may not be present. Patients may describe a long period of asymptomatic clunking that has now become painful. The other extremity should be assessed for similar symptoms because the instability is frequently bilateral. Clinical findings may include a volar sag at the ulnar wrist with a prominent-appearing ulnar head with the wrist at neutral. If a localized synovitis is present, tenderness may be present over the ulnar carpus, particularly at the triquetrohamate joint. If the patient is unable to actively reproduce the clunk, it may be passively reproduced with the midcarpal shift test.

Plain radiographic findings are often unremarkable because PMCI is a dynamic disorder. Videofluoroscopy is the imaging study of choice. Both posteroanterior and lateral projections should be taken as the patient moves the wrist form radial to ulnar deviation in an attempt to reproduce the clunk. In addition, arthroscopy can enable the surgeon to definitively exclude any other lesion, particularly proximal low ligament tears. The role of MRI in the evaluation of PMCI has not yet been defined.

Nonoperative treatment may include activity modification, use of NSAIDs, steroid injections, and splinting.

Surgical options include limited midcarpal arthrodesis, distal advancement of the volar ulnar arm of the arcuate ligament, dorsal radiocarpal capsulodesis, and suturing the palmar radioscaphocapitate ligament to the radiolunotriquetral ligament to close the space of Poirier.

Ulnar-Sided Wrist Pain - Author: Mr. David M Litchman - 21-06-2004: www.emedicine.com/orthoped/topic619.htm

Wrist Instability - Edited By: Ueli Buchler - from: 1996, as in chapter: 5 on page: 30 it says:

Midcarpal Instability:

Adaptive Carpus - Definition: Malalignment between first and second row which no longer colinear. This may be a consequence of:

*Distal Radial Fracture Malunion
*Scaphoid Fracture Nonunion or Malunion
*Other Causes Of Carpal Collopse Such As Advanced Kienbock's Disease, Capitat Bone Osteonecrosis.

Midcarpal Ligament Tear or Attenuation:

*Pain and 'Clunk' in hyperlax young patient after light injury or repeated stress
*After rotational significant injury in normal patients.

Preview Wrist Instability - Edited By: Ueli Buchler - From: 1996

wristinstability.multiply.com/journal/item/5

Post edited by: Scott_1984, at: 2009/02/08 10:00