Anatomic study of the pisotriquetral joint: ligament anatomy and cartilagenous change

The effect of ulnar variance on the pisotriquetral joint

BACKGROUND

Pisotriquetral joint (PTJ) disorders are an important cause of ulnar-sided wrist pain but are often underrecognized. Ulnar variance (UV) has been associated with several wrist pathologies.

PURPOSE

To determine the effect of UV on PTJ in patients with trauma.

MATERIAL AND METHODS

A total of 143 patients (77 men, 66 women; mean age=41.64 ± 18.07 years) were included. Patients with fractures, severe and high-energy trauma, arthritic conditions, avascular necrosis, congenital deformity, bone and soft-tissue tumors, suboptimal image quality, and incorrect joint position were excluded. UV and the amount of PTJ subluxation were evaluated using coronal and sagittal computed tomography images.

RESULTS

PTJ subluxation was divided into five grades. A statistically significant difference was found between the presence of PTJ subluxation and sex (P = 0.045). PTJ subluxation was more common in men (46.8%) than in women (30.3%). There was no significant difference between the presence of PTJ subluxation and age (P = 0.758). The patients were also divided into three groups as positive, neutral, and negative UV. A statistically significant relationship was found between the UV and presence of PTJ subluxation (P = 0.01). PTJ subluxation was significantly less in the neutral (none=51.1%, present=48.9%; P < 0.05) and negative (none=77.8%, present=22.2%; P < 0.05) groups.

CONCLUSION

PTJ subluxation was found to be less among the groups with neutral and negative UV in our study population. PTJ subluxation is more common in men while there is no relationship with age. UV and gender may be risk factors for PTJ subluxation by affecting force dynamics at the wrist joint.

Ultrasound-guided injection of the pisotriquetral joint: technique and case series

PURPOSE

To describe our techniques for ultrasound-guided injection of the pisotriquetral joint (PTJ), and to report our experience in a case series.

METHODS

Between 7/1/14 and 11/30/20, we performed 42 injections in 33 patients with ulnar-sided wrist pain, referred by clinicians who suspected the PTJ as the pain generator. There were 16 males and 17 females, average age 46.7 years. The patients were positioned in one of five ways: sitting with the hand maximally supinated; sitting with the hand maximally pronated; supine with the elbow flexed across the chest and the ulnar aspect of the wrist facing upward; supine with the elbow flexed, the arm externally rotated, and the ulnar aspect of the wrist facing upward; prone with the symptomatic hand at their side and the ulnar aspect of the wrist facing upward.

RESULTS

The procedures were performed by any of twelve fellowship-trained musculoskeletal radiologists. Fifteen patients reported immediate relief of symptoms, including 6 patients whose pisotriquetral joints were normal sonographically. Four patients underwent subsequent surgical excision of their pisiforms and the fifth underwent arthroscopic debridement of the pisotriquetral joint.

CONCLUSION

Ultrasound is a facile imaging modality for guiding pisotriquetral injections, which may be accomplished with a variety of patient positions and injection techniques.

MRI Findings in Patients Undergoing Triangular Fibrocartilage Complex Repairs Versus Patients Without Ulnar-Sided Wrist Pain

Background: The clinical picture of ulnar-sided wrist pain is oftentimes confusing because various pathologies may be coexistent. In this study, we aimed: (1) to compare the prevalence of potential causes of ulnar-sided wrist pain on magnetic resonance imaging (MRI) in patients who underwent triangular fibrocartilage complex (TFCC) repair and control subjects: and (2) to evaluate whether inferior clinical results were associated with specific patient characteristics or other potential causes of ulnar-sided wrist pain. Methods: We included 67 patients who underwent a TFCC repair and 67 control subjects. The MRI scans were examined for sources of ulnar-sided wrist pain. After TFCC repair, 42 patients (63%) completed surveys, including Quick Disabilities of the Arm, Shoulder and Hand and pain scores. Bivariate analysis was performed to compare our groups and to identify factors associated with our outcomes. Results: We found significantly higher rates of distal radioulnar joint (DRUJ) arthritis (P = .033), extensor carpi ulnaris (ECU) pathology (P = .028), and ulnar styloid fractures (P = .028) in patients with TFCC repairs. With increasing age, increasing pathology in the pisotriquetral joint (P = .040), more ulnocarpal abutment (P = .0081), and more degenerative tears (P < .001) were seen in both groups. No demographic characteristics or MRI findings were significantly associated with our outcomes. Conclusions: We observed higher rates of DRUJ arthritis and ECU pathology in patients with TFCC tears undergoing repair compared with age- and sex-matched controls. This may be due to damage to the TFCC itself altering relationships of the DRUJ and the ECU subsheath, or it may reflect various pathologies that cause ulnar-sided wrist pain and drive patients toward surgery.

Long-Term Results of Pisiformectomy in a Cohort of 57 Patients

Background  Excision of the pisiform is an infrequently used option for pisotriquetral joint dysfunction when nonoperative treatment is ineffective. This study reviews the patient-reported outcomes of patients treated with pisiformectomy, and furthermore focuses on the complications and the need for and time to revision procedure. Materials and Methods  Medical records of 57 patients were manually reviewed and assessed for complications, rate of unplanned reoperations, and type of reoperations. Thirty-seven patients (65%) completed patient-rated outcomes surveys at a median of 10 years after their procedure. Results  The complication rate was 13% ( n  = 7). Ulnar nerve symptoms were noted in three patients. No reoperations were performed after the pisiform excision. Out of the 16 patients who had preoperative symptoms of ulnar nerve compression at the wrist, 10 patients reported that their symptoms had completely resolved after the surgery. The median Quick Disability of Arm, Shoulder and Hand (QuickDASH) score after surgery was 4.5 (2.3-16), median score for pain 0 (interquartile range [IQR]: 0-2), and median score for overall satisfaction 10 (IQR: 8-10). Conclusions  Pisiformectomy is a surgery used sparingly in cases with refractory pain associated with arthrosis of the pisotriquetral joint or enthesopathy of the flexor carpi ulnaris/pisiform interface. When utilized in this fashion, patients report limited disability on patient-rated outcome measures, low pain scores, and high satisfaction at mid- to late follow-up.

Pisotriquetral Pain Treated with Bilateral Pisiform Excision in a Collegiate Diver

Background  Pisiform excision and pisotriquetral arthrodesis are two surgical options for the treatment of pisotriquetral joint pain when conservative methods fail. However, it is unclear which option is best for patients who experience substantial, repetitive loading on their wrists and wish to preserve wrist flexibility and function. Case Description  We present a case of bilateral ulnar-sided wrist pain related to the pisotriquetral joint in a 19-year-old collegiate diver. The pain was exacerbated by activities specific to this sport that requires wrist hyperextension, namely full weight-bearing on the hands (handstands), and has an impact on the hands and wrists upon water entry during dives due to direct palmar pressure. There were no radiographic signs of arthritis; however, there were bone marrow changes on magnetic resonance imaging (MRI). Management with rest, splinting, and corticosteroid injection failed to relieve the pain and precluded his ability to return to full-time diving. Treatment consisted of bilateral pisiform excision. Postoperatively, the patient returned to full-time competitive diving with resolution of his painful symptoms. Literature Review  Pisiform excision has been shown to have successful outcomes in terms of return to play for lower impact athletes (such as badminton) but has not been reported in athletes who experience a high degree of force repetitively (such as gymnasts or divers). There is one report of pisotriquetral arthrodesis in a young gymnast with suboptimal results. Clinical Relevance  This case report demonstrates that pisiform excision is a successful treatment for elite athletes who experience repetitive, palmar force on hyperextended wrists and subsequently develop ulnar-sided wrist pain.

Does pisiform subluxation affect the postoperative outcomes in a cohort of patients with distal radius fractures?

Background

In this study, we retrospectively surveyed the presence or absence of pisiform subluxation in surgically treated distal radius fractures (DRF) cases. In addition, we investigated whether or not the postoperative short-term treatment outcome differs due to the presence of pisiform subluxation.

Materials and methods

The subjects were 134 DRF patients treated with volar locking plate fixation (53 males and 81 females, mean age: 64 years old). The pisotriquetral joint was observed on a preoperative CT to investigate the presence or absence of pisiform subluxation according to the criteria reported by Vasilas. 134 patients divided into subluxation group and non-subluxation group, and the clinical outcomes were compared between these groups.

Results

Pisiform subluxation was noted in 23.1% (31 patients, 15 males and 16 females, mean age 61 years). No significant difference was noted in patient background in both groups. The postoperative pronation angle in the non-subluxation group was significantly greater than that in the subluxation group, but there was no significant difference in any other parameter (the range of motion of the wrist, grip strengths, VAS, Q-DASH scores, and Mayo score) between these 2 groups. However it concomitantly occurred in 23.1% of DRF cases in our series, there was no significant difference in the postoperative treatment outcome between these 2 groups.

Conclusions

Therapeutic intervention of pisiform subluxation is unnecessary during treatment of DRF, since pisiform subluxation does not affect the postoperative clinical outcomes of distal radius fractures.

•

Pisiform subluxation occurred in 23.1% of distal radius fracture cases, suggesting that it is not a rare pathology.

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Therapeutic intervention of pisiform subluxation may be unnecessary during treatment of distal radius fracture.

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The therapeutic intervention of pisotriquetral joint disorders should be considered when they develop.

Pisiform malalignment associated with distal radius fractures

BACKGROUND

The association of scaphoid or other carpal bone fractures with distal radius fractures is frequently reported, whereas few studies have described pisiform malalignment associated with distal radius fractures. The purpose of this study was to investigate the frequency and characteristics of pisiform malalignment associated with distal radius fractures.

METHODS

We performed a retrospective study by reviewing the data of 152 consecutive patients with a mean age of 63 years who were treated surgically for distal radius fractures during a five-year period. We evaluated the pisotriquetral joint via preoperative sagittal computed tomography (CT) and assessed pisiform malalignment. Pisiform malalignment was defined as follows: (1) wide type, joint space ≥4.0 mm; (2) non-parallel type, loss of parallelism of the joint surface of ≥20°; or (3) overriding type, proximal or distal overriding of the pisotriquetral joint ≥2.0 mm. We investigated the relationship between pisiform malalignment and the patterns of distal radius fractures. Pisiform malalignment was assessed using postoperative CT to determine whether it had been reduced.

RESULTS

Pisiform malalignment was observed in 48 cases involving 44 patients with a mean age of 58 (17-81) years. The patients included 16, 17, and 15 cases of the wide type, non-parallel type, and overriding type, respectively. Distal radius fractures with dorsal displacement exhibited pisiform malalignment significantly more frequently than those with volar displacement. No significant difference was noted between intra- and extra-articular fractures or between patients with and without distal ulnar fractures. Among the 22 pisiform malalignment cases assessed via postoperative CT, 15 cases were reduced, and 7 cases remained malaligned. The non-parallel type exhibited the lowest reduction rate among the 3 types.

CONCLUSIONS

Among distal radius fractures, 29% were complicated by pisiform malalignment. Distal radius fractures with dorsal displacement exhibited a significantly increased frequency of pisiform malalignment compared to those with volar displacement.

Treatment of Pisotriquetral Arthritis by Pyrocarbon Interposition Arthroplasty

Purpose  Pisiformectomy is the baseline treatment for pisotriquetral arthritis when medical treatment fails to address the problem. This operation may lead to loss of mobility and strength in the wrist. This study reports the short-term outcomes of a new technique for treating pisotriquetral arthritis using a pisotriquetral interposition arthroplasty with a pyrocarbon implant. Patients and Methods  We performed a clinical and radiographic study on a series of eight patients who received this treatment at a mean follow-up of 2.8 years. We also studied the mobility of the implant and did assessed articular instability using dynamic radiology and fluoroscopy. Results  We observed one proximal dislocation of the implant in one hand which was reoperated to reposition the implant and strengthen the capsule. All patients were satisfied or very satisfied with their operation and had an average functional recovery period of 1.6 months. At the last follow-up, the Mayo Wrist Score (MWS), Quick Disability of Arm Shoulder and Hand (QDASH), and Patient-Rated Wrist Evaluation (PRWE) scores were 89, 18, and 20, respectively. Postoperatively, there was a 22% improvement in the grip strength of the wrists as well as improved mobility, mainly as regards the radioulnar deviation (47% improvement) and the Visual Analogue Scale (VAS) pain scores decreased from 8 preoperatively to 2 at the latest follow-up. The functional radiologic and fluoroscopic study reported good adaptive mobility of the implant in all the patients, without any indication of pisotriquetral joint instability. Conclusion  The short-term results of pisotriquetral arthroplasty using the Pyrocardan implant are encouraging. This new surgical solution appears to be a valid alternative to pisiformectomy or pisotriquetral arthrodesis. Long-term studies are required to confirm these preliminary findings.

The Prevalence of Pisotriquetral Arthritis in the Setting of Scapholunate Advanced Collapse

Background Previous authors have reported pisotriquetral pain and subsequent pisiform excision following partial or total wrist fusion in patients with scapholunate advanced collapse (SLAC). Prior studies have not considered the potential role of SLAC biomechanics on pisotriquetral osteoarthritis (PT OA) development preoperatively. Purpose To determine the prevalence and severity of PT OA in patients with SLAC as compared with a control population. Patients and Methods Magnetic resonance imaging (MRI) studies of 24 patients with SLAC wrist and 24 sex- and age-matched control patients were analyzed. Patients with SLAC wrist were selected from a database of all wrist MRI studies performed at our institution from 2006 to 2015, excluding those with inflammatory arthritis, chondrocalcinosis, and incomplete or atraumatic scapholunate interosseous ligament rupture. Control patients underwent MRI for nonarthritic clinical indications and were chosen in an age- and sex-matched fashion. Patients undergoing MRI for triangular fibrocartilage complex injury, extensor carpi ulnaris tendinopathy, or ulnar-sided wrist pain were excluded from the control cohort. MRI grading of arthritic change at the pisotriquetral joint was assessed by a blinded musculoskeletal radiologist according to a four-category scale, with grade 4 indicating the greatest arthritic severity. Results The prevalence of PT OA in the control cohort was found to be 37.5% compared with 41.7% in the SLAC cohort. The prevalence of greatest arthritic severity (grade 4) at the pisotriquetral joint was found to be 4.2% in the control cohort, compared with 16.7% in the SLAC cohort. Conclusion We conclude that the overall prevalence of chondral wear at the pisotriquetral joint in SLAC wrist does not differ significantly from that found in control populations. We did identify a fourfold (but not statistically significant) increased prevalence of end-stage arthritis in patients with SLAC. Given reports of symptomatic PT OA developed following four-corner arthrodesis, we recommend preoperative vigilance for pisotriquetral pain in patients with SLAC arthritis. Level of Evidence Prognostic level III.

Common radiographic imaging modalities fail to accurately predict capitate morphology

BACKGROUND

There are three morphologies of the capitate based on its lunate and scaphoid articulations: flat, spherical, and V-shaped. Following a proximal row carpectomy (PRC), the capitate articulates with the lunate facet of the radius, altering contact biomechanics at the radiocarpal joint. Therefore, capitate morphology may influence contact pressures at the capitolunate articulation and influence clinical outcomes after PRC. However, it remains unclear which diagnostic imaging technique most reliably distinguishes between capitate morphologies.

METHODS

We evaluated the ability of plain radiographs, two-dimensional computed tomography (2D-CT), three-dimensional (3D)-CT reconstruction, and magnetic resonance imaging (MRI) to predict capitate type in 47 fresh frozen cadaver wrists. Two attending hand surgeons and one hand surgery fellow characterized capitate type based on each imaging modality. True capitate type was determined after gross dissection. We determined the reliability of each modality to predict capitate morphology.

RESULTS

We found all four imaging modalities to have a low sensitivity and specificity for predicting capitate morphology. Plain radiographs, 2D-CT, 3D-CT, and MRI had sensitivities/specificities of 0.46/0.57, 0.54/0.72, 0.54/0.52, and 0.56/0.65, respectively. All modalities had high negative predictive values for detecting the more rare V-shaped capitate subtype (range 91-94 %). Inter-rater reliability was poor for all modalities.

CONCLUSION

These data suggest that plain radiographs, CT, 3D-CT, and MRI are not helpful in preoperative determination of true capitate morphology. Plain radiographs are as effective as more cost-intensive modalities in ruling out V-shaped capitates.

[Is there pisotriquetral instability after carpal tunnel release? Retrospective study of 55 cases]

The aim of this study was to determine if pisotriquetral instability is present after neurolysis of the median nerve in the wrist. Fifty-five patients who underwent carpal tunnel release between December 2005 and March 2009 were included in this retrospective study. The surgical procedure consisted of cutting the transverse carpal ligament under local anesthesia through an anterior approach. Instability was evaluated clinically and radiologically by measuring the pisometacarpal angle. The mean patient age was 61years and the mean follow-up 42months. Only 9% of patients complained of pain on the ulnar side of wrist. The pisometacarpal angle in all the operated wrists was the same as in the non-operated wrists. Our findings suggest there is no pisotriquetral instability after median nerve neurolysis.

Pisiform excision for pisotriquetral instability and arthritis

PURPOSE

To evaluate wrist strength and kinematics after pisiform excision and preservation of its soft tissue confluence for pisotriquetral instability and arthritis.

METHODS

We evaluated 12 patients, (14 wrists) subjectively and objectively an average of 7.5 years after pisiform excision. Three additional patients were interviewed by phone. Subjective evaluation included inquiry about pain and satisfaction with the treatment. Objective testing included measuring wrist flexion and extension range of motion, grip strength, and static and dynamic flexion and ulnar deviation strengths of the operative hand compared with the nonsurgical normal hand. Four patients had concomitant ulnar nerve decompression at the wrist.

RESULTS

All patients were satisfied with the outcome. Wrist flexion averaged 99% and wrist extension averaged 95% of the nonsurgical hand. Mean grip strength of the operative hand was 90% of the nonsurgical hand. Mean static flexion strength of the operative hand was 94% of the nonsurgical hand, whereas mean dynamic flexion strength was 113%. Mean static ulnar deviation strength of the operative hand was 87% of the nonsurgical hand. The mean dynamic ulnar deviation strength of the operative hand was 103% of the nonsurgical hand.

CONCLUSIONS

Soft tissue confluence-preserving pisiform excision relieved pain and retained wrist motion and static and dynamic strength. Associated ulnar nerve compression was a confounding factor that may have affected outcomes.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Pisotriquetral joint disorders: an under-recognized cause of ulnar side wrist pain

Pisotriquetral joint disorders are often under-recognized in routine clinical practice. They nevertheless represent a significant cause of ulnar side wrist pain. The aim of this article is to present the main disorders of this joint and discuss the different imaging modalities that can be useful for its assessment.

In vivo length changes of wrist ligaments at full wrist extension

The aim of this study was to investigate the length changes of carpal ligaments when loaded in full extension in vivo. We obtained computed tomography scans of the right wrists in three positions for six volunteers: neutral; 75° extension; and 75° extension with a further 10° of radial deviation. Nine ligaments were measured and analysed with computer modelling. The results showed that the radioscaphocapitate, long radiolunate, and ulnolunate ligaments lengthened the most at full wrist extension, suggesting that they were under greatest load. The radioscapholunate, ulnocapitate, and ulnotriquetral ligaments lengthened further with the addition of wrist radial deviation. At full extension, the dorsal intercarpal ligament inserting on the scaphoid was lengthened. The dorsal radiocarpal and dorsal intercarpal ligaments inserting on the trapezoid were shortened, suggesting reduced loading. In conclusion, a number of volar carpal ligaments lengthened significantly in full wrist extension and the ulnar carpal ligaments were further lengthened at wrist radial deviation.

The pisotriquetral joint: osteoarthritis and enthesopathy

Pisotriquetral (PT) osteoarthritis (OA) and enthesopathy of the flexor carpi ulnaris (FCU) are pathologies of the hypothenar eminence which both often remain undiagnosed, but can cause ulnar wrist pain. This study determined the prevalence of these pathologies in an older donor population. Twenty wrists were obtained from 10 cadavers with an age ranging from 65 to 94 years. Radiographs were taken of all wrists with the hand in pisotriquetral view and were assessed for osteoarthritic changes of the PT joint and signs of enthesopathy of the FCU. Ten wrists were grossly dissected and the other ten wrists were sagitally sectioned at a thickness of 10 μm. The wrists were analyzed for type and grade of osteoarthritis and signs of enthesopathy. On radiology, 2 out of 20 wrists showed no signs of osteoarthritis, 5 wrists showed severe changes. One wrist showed signs of enthesopathy. On macroscopy, 9 out of 10 wrists showed osteoartritic changes; 5 of these were severely osteoarthritic. On microscopy, all wrists showed some degree of osteoarthritis of which five showed severe changes. Signs of enthesopathy were seen in seven wrists. Pisotriquetral osteoarthritis has a high prevalence in the older donor population and may therefore be a cause of ulnar sided wrist pain. It should therefore always be considered in the differential diagnosis of ulnar sided wrist pain. By performing clinical examination with these pathologies in mind, diagnosis could be a lot faster. Furthermore, based on our results, radiographs seem to be not accurate in diagnosing osteoarthritis of the PT joint and enthesopathy of the FCU.

A novel method to replicate the kinematics of the carpus using a six degree-of-freedom robot

Understanding the kinematics of the carpus is essential to the understanding and treatment of wrist pathologies. However, many of the previous techniques presented are limited by non-functional motion or the interpolation of points from static images at different postures. We present a method that has the capability of replicating the kinematics of the wrist during activities of daily living using a unique mechanical testing system. To quantify the kinematics of the carpal bones, we used bone pin-mounted markers and optical motion capture methods. In this paper, we present a hammering motion as an example of an activity of daily living. However, the method can be applied to a wide variety of movements. Our method showed good accuracy (1.0-2.6°) of in vivo movement reproduction in our ex vivo model. Most carpal motion during wrist flexion-extension occurs at the radiocarpal level while in ulnar deviation the motion is more equally shared between radiocarpal and midcarpal joints, and in radial deviation the motion happens mainly at the midcarpal joint. For all rotations, there was more rotation of the midcarpal row relative to the lunate than relative to the scaphoid or triquetrum. For the functional motion studied (hammering), there was more midcarpal motion in wrist extension compared to pure wrist extension while radioulnar deviation patterns were similar to those observed in pure wrist radioulnar deviation. Finally, it was found that for the amplitudes studied the amount of carpal rotations was proportional to global wrist rotations.

Effect of pisiform excision or pisotriquetral arthrodesis as a treatment for pisotriquetral arthritis: a biomechanical study

PURPOSE

To determine whether flexor carpi ulnaris (FCU) forces and tendon displacements change after pisotriquetral arthrodesis or after pisiform excision.

METHODS

Nine cadaver wrists were moved through 4 variations of a dart throw motion, each having an oblique plane of motion, but with different ranges of motion and different antagonistic forces. The FCU tendon force and movement were measured in the intact wrist, following pisotriquetral arthrodesis, and following pisiform excision. Changes in force and tendon movement were compared using a repeated measures analysis of variance.

RESULTS

After excision of the pisiform, a significantly greater FCU force was required during the 2 variations of the dart throw motion having a larger range of motion and during the smaller motion having a larger antagonistic force. Pisotriquetral arthrodesis did not cause a significant increase in the peak FCU force. Excision of the pisiform caused the FCU tendon to significantly retract during all wrist motions as compared to the intact wrist or after pisotriquetral arthrodesis.

CONCLUSIONS

Greater FCU forces are required to move the wrist when the pisiform with its moment arm function has been removed. This occurs during large oblique plane wrist motions and also in a smaller motion when greater antagonistic forces are applied. Excision of the pisiform also allows the FCU to move proximally, again because its moment arm function has been eliminated.

CLINICAL RELEVANCE

Excision of the pisiform requires greater FCU forces during large wrist motions and during motions that include large gripping forces such that excision may be a concern in high-demand patients with pisotriquetral arthritis. Although pisotriquetral arthrodesis does not alter the mechanical advantage of the FCU, its use in high-demand patients with pisotriquetral osteoarthritis cannot yet be recommended until the effects of that arthrodesis on midcarpal kinematics are further clarified.

Contact pressure in the wrist during computer mouse work

This study investigated the relationship between computer mouse work and contact pressure around the pisiform. Commonly performed mouse work was simulated using 3 different-shaped mice with 3 forearm positions. When typical mouse work was performed, the contact pressure on the pisiform area was evaluated using a digital pressure sensor and compared with that of the thenar area. Six mouse tasks were simulated. Results indicate that mouse users should avoid wrist-snap dragging and resting their wrist on the edge of the desk to minimize the pressure concentration on the pisiform area.

Anatomical study of the pisotriquetral joint ligaments using ultrasonography

OBJECTIVE

The aim of this study was to demonstrate that ultrasonography may allow a precise assessment of the primary stabilizers of pisotriquetral joint (pisohamate, pisometacarpal, and ulnar pisotriquetral ligaments).

METHODS AND MATERIALS

This study was initially undertaken in eight cadavers. Metal markers were placed in the ligaments using ultrasonographic guidance, followed by the dissection of the wrists. High-resolution ultrasonography was then performed in 15 volunteers (30 wrists) for the analysis of the presence, appearance, and thickness of the ligaments.

RESULTS

At dissection, the metal markers were located in the ligaments or immediately adjacent to them, confirming that they were correctly depicted using ultrasonography. The three ligaments could also be identified in each volunteer. The optimal positioning of the probe and the dynamic maneuvers of the wrist allowing the strain of these ligaments could be defined. No significant changes in the appearance and thickness of the ligaments could be observed.

CONCLUSIONS

The three ligaments stabilizing the pisotriquetral joint can be identified using ultrasonography. Further studies are now required to know whether this knowledge may be useful in the assessment of pain involving the ulnar part of the wrist.

In vivo length changes of carpal ligaments of the wrist during dart-throwing motion

PURPOSE

The dart-throwing motion is an important movement pattern during most wrist actions. The aim of this study was to investigate length changes in the wrist ligaments in different positions of the dart-throw motion in vivo.

METHODS

We obtained computed tomography scans of the wrists of 6 volunteers at 5 positions of the wrist during the dart-throw motion: 20° of radial deviation with 60° of extension; 10° of radial deviation with 30° of extension; the neutral position of the carpus; 20° of ulnar deviation with 30° of flexion; and 40° of ulnar deviation with 60° of flexion. We reconstructed the 3-dimensional carpal and distal radioulnar joint structures with customized software and computed changes in length of 8 palmar and dorsal wrist ligaments.

RESULTS

From wrist radial deviation with extension to ulnar deviation with flexion, the radioscaphocapitate, long radiolunate, ulnocapitate, and ulnotriquetral ligaments decreased significantly in length but the dorsal radiocarpal ligament and the dorsal intercarpal (DIC) ligament inserting on the trapezoid lengthened significantly; the ulnolunate ligament and the DIC ligament inserting on the scaphoid were shortest in neutral position.

CONCLUSIONS

At wrist radial extension, the radioscaphocapitate, long radiolunate, ulnocapitate, and ulnotriquetral ligaments are lengthened and under increased tension. At wrist ulnar flexion, the dorsal radiocarpal ligament and the DIC ligament inserting on the trapezoid are lengthened and under increased tension. The ulnolunate ligament and the DIC ligament inserting on the scaphoid are the shortest and under the least tension in neutral position. These findings will help us understand the biomechanics of the carpus during the dart-throwing motion.

Latent pisotriquetral arthrosis unmasked following carpal tunnel release

The causes of persistent wrist pain following carpal tunnel release include scar tenderness and pillar pain. The goal of this study was to evaluate latent pisotriquetral arthrosis as a source of ulnar-sided wrist pain following open carpal tunnel release. Seven hundred consecutive carpal tunnel releases were reviewed, looking for postoperative presentation of pisotriquetral arthrosis, as well as management and outcome. Fourteen patients with long-standing postoperative pain at the base of the hypothenar eminence had clinical and radiographic signs of pisotriquetral degenerative arthrosis, which conceivably had existed preoperatively and been unmasked thereafter. In 6 patients with persistent symptoms despite conservative measures, excision of pisiform was curative. Altered isometric stresses over the pisotriquetral articulation as a result of releasing the transverse ligament, which constitutes a major radial static stabilizer of this joint, seems to cause articular maltracking, and consequently aggravates a preexisting asymptomatic pisotriquetral arthrosis. Long-standing discomfort is characteristically associated with loss of grip strength and dexterity. Pisotriquetral dysfunction and arthrosis should always be considered in the differential diagnosis of persistent wrist pain following either open or endoscopic carpal tunnel release that does not respond to nonoperative measures. Clinical scrutiny, adequate clinical inspection, and radiographic evaluation readily establish the diagnosis. Conservative treatment includes immobilization, nonsteroidal anti-inflammatory drugs, and intra-articular injection of corticosteroids under fluoroscopic control. The corticosteroid injection combined with a local anesthetic also serves as a diagnostic test. Excision of the pisiform is indicated where conservative treatment has failed.

In vivo length changes of selected carpal ligaments during wrist radioulnar deviation

PURPOSE

To investigate changes in the lengths of selected carpal ligaments during wrist radioulnar deviation in vivo.

METHODS

We studied in vivo changes in the lengths of fibers of 5 palmar and dorsal intracapsular ligaments of the wrist during radioulnar deviation in 6 wrists of healthy volunteers using a noninvasive approach. Using serial computed tomography scans and volume registration techniques, the carpal kinematics were examined at 4 positions, from 40 degrees ulnar deviation to 20 degrees radial deviation, in 20 degrees increments. The 3-dimensional structures of the carpal bones, distal radius and ulna, and metacarpal bones were reconstructed using customized software. We modeled the paths of fibers of 5 palmar and dorsal carpal ligaments: radioscaphocapitate (RSC), long radiolunate (LRL), ulnocapitate (UC), dorsal intercarpal (DIC), and dorsal radiocarpal (DRC) ligaments. We analyzed changes in the lengths of these ligaments during wrist radioulnar deviation.

RESULTS

During wrist ulnar deviation, the RSC, LRL, and DIC ligaments lengthened significantly. During radial deviation, the UC and DRC ligaments lengthened significantly. Compared with their lengths at the neutral position of the carpus, the LRL ligament showed the greatest elongation rate at wrist ulnar deviation, and the DRC ligament showed the greatest elongation rate at wrist radial deviation among the 5 ligaments studied.

CONCLUSIONS

Among ligaments measured, the RSC, LRL, and DIC ligaments are tensed during wrist ulnar deviation. The UC and DRC ligaments are tensed during wrist radial deviation. Results of this in vivo study suggest that radial or ulnar deviation may predispose some carpal ligaments to excessive tensile load. The finding that the ligaments undergo different elongation rates during wrist motion may also indicate their roles in maintaining normal wrist kinematics.

Variations of capitate morphology in the wrist

PURPOSE

This anatomical study details and categorizes variations in capitate morphology and associated structures in the human cadaveric wrist.

METHODS

We dissected 107 cadaveric wrists. Capitate morphology, the presence of capitate and hamate ridges, the lunate types, and the width of the medial hamate facet of type II lunates and 4th carpometacarpal joint types were recorded.

RESULTS

Three types of capitate were identified. The flat type (69/107, or 65%) was characterized by a horizontally oriented (radio-ulnar) lunate-capitate articulation and a longitudinally oriented (proximal-distal) scaphoid-capitate articulation. The flat type was associated with type I lunates or type II lunates with a smaller facet. The spherical type (23/107, or 22%) was associated with a concave articulation formed by the scaphoid and lunate articulations, with an indistinct border between the scaphoid and lunate facets. The width of the medial hamate facet of type II lunates in wrists with a spherical-type capitate was <or=4 mm. The V-shaped type (15/107, or 14%) was characterized by separate lunate and scaphoid facets that converge, forming a V-shape. All the V-shaped capitates had a type II lunate with a large facet.

CONCLUSIONS

A relationship was found between the 3 capitate types and both the lunate types and the width of the medial hamate facet of the type II lunates. Further study is warranted to determine if these differences in capitate morphology influence the development or progression of various wrist pathologic conditions, such as Kienböck's disease and post-traumatic arthritis associated with scapholunate dissociation and scaphoid nonunion, and the outcome of certain surgical procedures, such as a proximal row carpectomy.

Pisotriquetral dysfunction following limited and total wrist arthrodesis

PURPOSE

We report a series of pisotriquetral arthritis cases following wrist and intercarpal arthrodesis, offer an anatomic and biomechanical rationale, and introduce intraoperative considerations to avoid this potential complication.

METHODS

Nine patients with pisotriquetral arthritis requiring pisiform excision following wrist and intercarpal arthrodesis were retrospectively evaluated at 2 institutions. Five paired cadaver wrists were tested for alterations in pressure and kinematics of the pisotriquetral joint following four-corner and total wrist fusions.

RESULTS

Nine patients were successfully treated with pisiform excision for pisotriquetral arthritis following wrist and intercarpal fusions. Biomechanical cadaver testing demonstrated profound alterations in pisotriquetral kinematics and pressure changes in measured degrees of wrist position following wrist and intercarpal fusions.

CONCLUSIONS

Patients undergoing four-corner and/or wrist arthrodesis should be assessed for pisotriquetral discomfort before surgery, including a physical examination and a 30 degrees supinated radiograph to look for degenerative changes. Attempts should be made intraoperatively to ensure that the proximal row is not fused in an extended position. After surgery, if discomfort develops and conservative treatment fails, then pisiform excision can successfully alleviate the pain.

Osteoarthritis of the wrist

Osteoarthritis of the wrist is one of the most common conditions encountered by hand surgeons. It may result from a nonunited or malunited fracture of the scaphoid or distal radius; disruption of the intercarpal, radiocarpal, radioulnar, or ulnocarpal ligaments; avascular necrosis of the carpus; or a developmental abnormality. Whatever the cause, subsequent abnormal joint loading produces a spectrum of symptoms, from mild swelling to considerable pain and limitations of motion as the involved joints degenerate. A meticulous clinical and radiographic evaluation is required so that the pain-generating articulation(s) can be identified and eliminated. This article reviews common causes of wrist osteoarthritis and their surgical treatment alternatives.

Visualisation of the pisotriquetral joint through standard portals for arthroscopy of the wrist

Disorders of the pisotriquetral joint are well recognised as the cause of pain on the ulnar side of the wrist. The joint is not usually examined during routine arthroscopy because it is assumed to have a separate joint cavity to the radiocarpal joint, although there is often a connection between the two.

We explored this connection during arthroscopy and in fresh-frozen cadaver wrists and found that in about half of the cases the pisotriquetral joint could be visualised through standard wrist portals. Four different types of connection were observed between the radiocarpal joint and the pisotriquetral joint. They ranged from a complete membrane separating the two, to no membrane at all, with various other types of connection in between.

We recommend that inspection of the pisotriquetral joint should be a part of the protocol for routine arthroscopy of the wrist.

Three-dimensional analysis of the ligamentous attachments of the second through fifth carpometacarpal joints

The purpose of this study is to clarify, measure, and show the anatomic locations and areas of specific ligamentous attachments and paths of the second through fifth carpometacarpal (CMC) joints on a three-dimensional (3D) surface model. Ten fresh-frozen cadaver wrists were used to dissect and identify the second through fifth CMC ligaments. Their ligamentous attachments and whole bone surfaces were digitized three-dimensionally and their areas calculated. The attachments of each ligament were represented in a model combining CT surfaces overlaid by a digitized 3D surface, and were also visually demonstrated with a specific color on 3D images of the bones. Nine dorsal and 11 palmar CMC ligaments and one CMC interosseous ligament were identified in the second through fifth CMC joints. An intra-articular ligament between the third metacarpal (MC), the fourth MC, capitate, and hamate was also identified. Five dorsal and five palmar intermetacarpal ligaments and three intermetacarpal interosseous ligaments were also identified in the second through fifth intermetacarpal joints. A previously undescribed palmar intermetacarpal ligament was located between the third, fourth, and fifth MC bases. The anatomic 3D attachment sites of the second through fifth CMC ligaments were visually depicted qualitatively, and their areas quantified. This 3D information will not only afford a better understanding of the anatomy and mechanics of the second through fifth CMC joints, but will also assist in the assessment of radiographic images and treatment of various injuries.

Pathologic Conditions of the Hypothenar Eminence: Evaluation with Multidetector CT and MR Imaging

Pain, weakness, and sensory loss occur frequently in the hypothenar eminence. However, clinical examination is difficult and nonspecific, and the prescribed imaging technique may be inadequate, or images may be misinterpreted. Different imaging modalities have various degrees of usefulness for the diagnosis of painful pathologic conditions of the hypothenar eminence. Radiography, multidetector computed tomography (CT), multidetector CT arthrography, and magnetic resonance (MR) imaging of the wrist are useful for surveying the anatomy of the hypothenar eminence, the Guyon canal, and the ulnar nerve and artery and for determining the cause of pain or other symptoms. A fracture of the pisiform bone or the hook of the hamate bone, osteoarthritis or osteochondromatosis of the pisotriquetral joint, Guyon canal syndrome, hypothenar hammer syndrome, tendinopathy of the flexor carpi ulnaris, an anomalous muscle, a ganglion cyst, or a tumor may be responsible for ulnar neuropathy. Specific radiographic views, such as the semisupinated oblique view and the lateral view with the hand radially deviated and the thumb abducted, often provide a sufficient basis for the diagnosis of acute fracture of the hook of the hamate or the pisiform bone. Multidetector CT angiography is an efficient method for diagnosing hypothenar hammer syndrome, and multidetector CT arthrography is well suited for evaluation of the pisotriquetral joint. MR imaging is the modality of choice for depiction of the ulnar nerve.

Pisotriquetral arthrodesis as an alternative to excision for pisotriquetral instability in high-demand patients: a case report in a gymnast

A gymanast developed ulnar wrist pain caused by pisotriquetral instability. Pisotriquetral arthrodesis resulted in pain relief and sufficient functional return to allow her to return to gymnastics. Pisotriquetral arthrodesis is a feasible alternative to pisiform excision worth consideration in high-demand patients with symptomatic pisotriquetral instability or arthrosis.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic, Level V.

Pisiform ligament complex syndrome and pisotriquetral arthrosis

PLC syndrome is a spectrum that encompasses PLC instability and ends with PTA. Early recognition and treatment of PLC instability may disrupt its progression to PTA. The pisiform tracking test is a provocative maneuver that aids in diagnosing PLC syndrome. Pisiformectomy with preservation of the soft tissue confluence remains the treatment of choice for severe PLC syndrome that does not respond to nonoperative treatment.

The pisotriquetral joint: anatomic, biomechanical, and radiographic analysis

PURPOSE

To examine anatomically and radiographically the ligaments stabilizing the pisotriquetral (PT) joint and to determine the contribution of each ligament to the stability of this joint.

METHODS

Twelve cadaver arms were used. The study had 3 components: (1) anatomic dissection of the PT joint ligaments and patterns of degenerative changes, (2) biomechanical sequential sectioning of the supporting ligaments, and (3) radiographic assessment of PT joint motion in several planes both before and after ligament sectioning.

RESULTS

The ligaments that attached to the pisiform were the pisometacarpal (PM), pisohamate (PH), radial PT, ulnar PT, and transverse carpal ligament. The PH ligament was shorter, wider, and thicker than the PM ligament. The transverse carpal ligament attachment in the pisiform was insubstantial. In 10 limbs degenerative changes were present, most of them peripheral. Biomechanical testing showed that the primary stabilizers of the PT joint were the PM, PH, and ulnar PT ligaments and that these were responsible for resisting proximal, ulnar, and radial forces, respectively. The PH distance increased along with the pisiform sagittal motion during wrist flexion on oblique x-rays after transection of the PM and ulnar PT ligaments. Concomitantly this distance decreased on the anteroposterior x-rays during radial deviation. The PH distance increased along with the pisiform frontal motion after transection of the PH and radial PT ligaments.

CONCLUSIONS

The pisiform ligament complex has primary and secondary stabilizers to the PT joint. The primary stabilizers are the PH, PM, and ulnar PT ligaments. The transverse carpal and radial PT ligaments are secondary stabilizers. Injuries of the primary stabilizers of the PT joint may lead to instability that predisposes to degenerative joint disease.

Dysfunction of the pisotriquetral joint: degenerative arthritis treated by excision of the pisiform

From 1995 to 2000, 21 patients (14 women and 7 men) with a mean age of 42 were treated with excision of the pisiform for a dysfunction of the pisotriquetral joint. Follow-up ranged from 6 to 36 months (average: 30 months). The diagnoses included degenerative arthritis of the pisotriquetral joint (15 patients), degenerative arthritis associated with a ganglion (3 patients), and calcifications caused by flexor carpi ulnaris tendinopathy (3 patients). All patients had pain secondary to direct pressure on the pisiform. Side-to-side passive motion of the pisiform occasionally led to pain and crepitus. Degenerative arthritis and calcifications in the pisotriquetral joint were confirmed by a wrist radiograph (lateral view in 30 degrees supination). In five patients, local injection with anesthetic temporarily resolved the symptoms. Excision of the pisiform resulted in complete relief of pain without functional deficit.

Pisotriquetral instability causing an unusual flexor tendon rupture

We present a case of a closed rupture of the flexor digitorum profundus tendon of the small finger. It is our hypothesis that because of pisotriquetral instability as a result of a lesion of the pisotriquetral ligaments the flexor digitorum profundus tendon was entrapped repeatedly between the pisiform and triquetrum. This resulted in an attritional lesion of the tendon. The pisotriquetral joint showed no bone abnormalities.

Wrist kinetics after luno-triquetral dissociation: the changes in moment arms of the flexor carpi ulnaris tendon

Wrist biomechanics after luno-triquetral (LT) dissociation is important for understanding the clinical sequelae of the disease and for determining its treatment options. The LT interosseous ligament plays an important role in stabilizing the joint and damage to the ligament would be expected to significantly increase moment arms of tendon of the flexor carpi ulnaris (FCU), the principal ulnar wrist flexor. We investigated the changes in moment arms of FCU tendon after various amounts of sectioning of the ligaments proven to be associated with LT dissociation. In six fresh frozen cadaveric upper extremities, excursions of the FCU tendon were recorded simultaneously with wrist joint angulation during wrist flexion-extension and radioulnar deviation. Tendon excursions were measured in intact wrists, in wrists with sectioning of the dorsal portion of the LT interosseous ligament, in wrists with sectioning of the entire LT interosseous ligament, and finally in wrists with further sectioning of the dorsal radiotriquetral and intercarpal ligaments. Moment arms of the tendon were calculated from tendon excursions and joint motion angulations and expressed as percentage changes from those in the intact wrist. During wrist flexion-extension, moment arms of the FCU tendon after sectioning of the entire LT interosseous ligament and after sectioning of the two capsular ligaments were 112 +/- 7% and 114 +/- 8%, respectively; these values were significantly greater than those in the intact wrist. During radioulnar deviation, the moment arms were 114 +/- 11% after sectioning of the dorsal portion of the LT interosseous ligament, 134 +/- 15% after sectioning of the entire ligament, and 153 +/- 18% after sectioning of the capsular ligaments, again being significantly greater than the normal wrist. Increase in moment arms of the FCU tendon after loss of integrity of the LT interosseous ligament and dorsal capsular ligaments may contribute to clinical sequelae of LT dissociation and difficulty in treating this disorder.

Radiographic analysis of pisotriquetral joint and pisiform motion

We evaluated 45 wrists of normal volunteers fluoroscopically (15) and radiographically (30) to determine the optimal radiographic technique for profiling the pisotriquetral (PT) joint and to assess the pisiform motion. Real-time fluoroscopy showed that 4 views are necessary for optimal PT joint and pisiform visualization: wrist neutral/30 degrees forearm supination, wrist extension/30 degrees forearm supination, and active plus passive wrist flexion/45 degrees forearm supination with thumb abduction. Excursion percentage of the PT articular surface apposition on video imaging occurred 10% proximally in neutral, 20% distally in extension, and 40% proximally in flexion. Radiography showed pisiform excursion distally (2.5 mm) in extension and proximally with active (3 mm) and passive (2 mm) flexion. Pisotriquetral angle opened proximally (15 degrees ) in extension and distally with active (10 degrees ) and passive (5 degrees ) flexion. Pisotriquetral space averaged 1.5 mm in neutral, 1 mm in extension, 3.5 mm in active, and 3 mm in passive flexion. Pisohamate distance averaged 7.5 mm in neutral, increased to 8 mm in extension, and decreased to 2 mm with active and 0 mm with passive flexion. These views and parameters are useful for evaluating patients with PT joint injury and disease.

[Piso-triquetral osteoarthritis. Thirteen case reports and review of the literature]

Piso-triquetral osteoarthritis (OA) is an infrequent cause of ulnar wrist compartment pain. Specific clinical manoeuvres may help for diagnosis. If this aetiology is suspected, a 30 degrees oblique wrist X-ray in supination and sometimes a CT scan with transverse cuts should be performed demonstrating a joint narrowing and osteophytes formation. The FCU-pisiform biomechanical unit transfers the wrist flexion forces. A series of 13 cases of piso-triquetral OA is presented in 12 patients (six females and six men) treated between 1990 and 1997. Mean age was 52.7 y. Pain at resisted motion in flexion and ulnar deviation and strength decrease was always present at clinical examination. Subperiosteal pisiform excision has been constantly performed. Continuity of FCU insertions and its distal ligamentous extensions has been preserved. Mean F-up was 18.1 months (3-57). Pain has disappeared in seven cases and significantly decreased in five. NSD was present in one case. Range of motion and strength was normal in all cases. Ulnar nerve paresthesias has always disappeared. The pisiform bone is not a sesamoid: a true joint with the triquetrum exists. From the phylogenetic point of view, three theories have been proposed: (a) in some species, pisiform is fused with adjacent bones or metacarpals; (b) pisiform is a remnant of a polydactyly hand; (c) pisiform is a remnant of the carpal central row.

Pisotriquetral joint: assessment with MR imaging and MR arthrography

PURPOSE

To evaluate magnetic resonance (MR) imaging and MR arthrographic findings in the pisotriquetral joint (PTJ) and their contribution to assessment of PTJ osteoarthritis.

MATERIALS AND METHODS

Images of 22 fresh human cadaveric PTJs were obtained with both conventional and arthrographic MR techniques. The MR appearances of all intraarticular and periarticular structures were analyzed and correlated with anatomic slices. Two readers graded visibility of anatomic structures and severity of joint abnormalities. Differences in the visibility ratings at standard MR imaging and at MR arthrography were calculated. Association between the type of pisiform insertion of ligament or muscle with cartilaginous abnormalities of the PTJ was assessed. The association between cartilaginous lesions and osteoarthritic changes was calculated.

RESULTS

The tendon sheath, the fibrous capsule, and cartilaginous surfaces were better visualized at MR arthrography than at MR imaging. Pisohamate and pisometacarpal ligaments were slightly better seen on MR arthrograms. Tendons, muscles, and retinacular structures were well demonstrated at both conventional MR and MR arthrography. Cartilaginous lesions and osteophytes were easily identified and were detected more often in the pisiform bone than in the triquetral bone. Communication of the PTJ with the radiocarpal joint was noted in 18 (82%) of 22 wrists.

CONCLUSION

MR imaging and/or MR arthrography allows visualization of all anatomic structures of the PTJ. MR arthrography improves visualization of findings of osteoarthritis.

Pisiform kinematics in vivo

The purpose of this study was to quantify in vivo pisiform kinematics. Wrists of healthy volunteers were imaged by spiral computed tomography during ulnar-radial deviation (n = 11) and during flexion-extension (n = 5). Relative translations and rotations of the carpal bones were determined by using a 3-dimensional matching technique. The error of this registration procedure was less than 0.5 mm for translation and 0.4 degrees for rotation. With radial wrist deviation the pisiform flexes while the triquetrum extends; with ulnar deviation the triquetrum shows more ulnar deviation and extension. With wrist extension the pisiform translates over the distal part of the triquetrum while being pressed against it. With flexion the pisiform moves away from the triquetrum while translating proximally. These in vivo findings provide a further explanation for certain clinical entities, such as degenerative changes of the pisotriquetral joint, and may be used as a reference for normal kinematics of the pisiform.

A reliable technique for radiographic imaging of the pisotriquetral joint

We report a novel technique for radiographic imaging of the pisotriquetral joint. This technique has proved useful for five consecutive patients presenting with pisotriquetral osteoarthritis. It is consistently reliable in imaging the joint and reduces the number of unsuccessful radiographic attempts.