Variations of capitate morphology in the wrist

Proximal row carpectomy or scaphoid excision and four-corner arthrodesis for treatment of scapholunate advanced collapse arthritis

Degenerative wrist conditions, such as scapholunate advanced collapse and scaphoid nonunion advanced collapse, often require salvage procedures to reduce pain and improve function. For early stages of disease, both proximal row carpectomy and scaphoid excision four-corner arthrodesis are viable motion-preserving options. There remains controversy on which technique is superior. Selection is a nuanced decision that requires consideration of patient characteristics and stage of disease. The traditional notion that proximal row carpectomy should be reserved for older individuals with low demands has been challenged; long-term studies in younger populations demonstrate similar patient-reported outcomes, pain relief and survivorship without conversion to total wrist arthrodesis between proximal row carpectomy and four-corner arthrodesis. The existing evidence suggests proximal row carpectomy has advantages of greater range of motion, fewer complications and lower costs. Advancements such as arthroscopic techniques for both procedures show potential, although mastery involves a steep learning curve.

The Three-Dimensional Relationship of the Axes of the Capitate and Third Metacarpal

PURPOSE

We quantified the morphology and angulation of the third metacarpal (MC3) relative to the capitate using three-dimensional computed tomography data to inform surgical procedures such as total wrist arthroplasty and wrist arthrodesis. Specifically, we report the three-dimensional location of the intersections of the long axis of MC3 axis with the capitate cortical surface, the sagittal and coronal angles between the MC3 and capitate axes, and the MC3 shaft angle in the sagittal plane. We tested the hypothesis that these metrics did not differ between women and men.

METHODS

Three-dimensional bone models of the capitate and MC3 were analyzed in 130 subjects (61M and 69F). Long axes of the MC3 and capitate were computed. The intersection of the metacarpal long axis with the cortical surface of the capitate, the angle between the metacarpal-capitate axes, and metacarpal shaft angle were calculated and compared between men and women.

RESULTS

The long axis of the MC3 intersected the capitate at two locations on the outer cortical surface of the capitate. The proximal intersection was located near the midportion of the capitate, whereas the distal intersection was typically located within the capitate-MC3 articulation. The angle between the axes of the capitate and MC3 in the sagittal plane was a mean of 15°, ranging from 5° to 23°. The mean sagittal MC3 shaft angle was 166° and ranged from 158° to 173°.There were only subtle differences in these metrics between the sexes.

CONCLUSIONS

The long axis of the MC3 penetrates the dorsal surface of the capitate about its midportion, but there is notable variation in this location as well as in the angular relationships.

CLINICAL RELEVANCE

Three-dimensional measurements of the relationships between the third metacarpal and the capitate may serve as an important reference for the placement of intramedullary wires, plates, devices, and prosthetics.

Distal Scaphoid Excision for Chronic and Nonchronic Scaphoid Fracture Nonunion

Purpose

The indications for distal scaphoid excision are limited to localized wrist arthritis surrounding the scaphoid, as a result of scaphoid nonunion advanced collapse or scapho-trapezio-trapezoid joint arthritis. The procedure historically has led to relief of symptoms and improvement in strength. Our aim was to examine the outcomes of this procedure in patients with scaphoid fracture nonunion.

Methods

This is a single-center retrospective case series of 12 consecutive patients who underwent distal scaphoid excision after scaphoid fracture nonunion. Patients were divided into the following two groups based on nonunion chronicity: chronic (more than a year) and nonchronic (less than a year). Clinical and radiographic data were examined using descriptive statistics.

Results

Our cohort consisted of 12 patients, 10 men (83%) and 2 women (17%), with a mean age of 37.6 ± 13.6 years. Eight patients had a chronic scaphoid fracture nonunion (six had a neglected scaphoid fracture and two had a nonunion after scaphoid open reduction and internal fixation with bone graft), and four patients had a nonchronic fracture nonunion (two had failed cast treatment and two had nonunion after scaphoid open reduction and internal fixation with bone graft). Before surgery, all patients complained of pain and four had numbness (all in the chronic group). After an average of 21 weeks after surgery, seven patients (58%) reported continued pain, two patients reported ulnar side pain, and one underwent arthroscopic synovectomy. All patients who started with a normal radiolunate angle continued to have a normal angle, whereas patients who had dorsal intercalated segmental instability prior to surgery persisted with it after surgery, except for a patient who underwent midcarpal fusion and had their radiolunate angle corrected.

Conclusions

Distal scaphoid excision is an effective procedure for carefully selected patients with periscaphoid wrist arthrosis. Patients with recent scaphoid fractures that failed treatment may also be treated with distal scaphoid resection.

Type of study/level of evidence

Therapeutic V.

Sex-Specific Size Analysis of Carpal Bones: Implications for Orthopedic Biomedical Device Design and Therapy Planning

Consideration of the individual carpal bone characteristics of the wrist plays a key role in well-functioning biomedical devices and successful surgical procedures. Although geometric differences and individual bone sizes have been analyzed in the literature, detailed morphologic descriptions and correlations covering the entire wrist reported in a clinical context are lacking. This study aimed to perform a comprehensive and automatic analysis of the wrist morphology using the freely available "Open Source Carpal Database" (OSCD). We quantified the size of each of the individual carpal bones and their combination. These sizes were extracted in n = 117 datasets of the wrist of the OSCD in anatomical directions and analyzed using descriptive statics and correlation analysis to investigate the morphological characteristics under sex-specific aspects and to provide regression plots and equations to predict individual carpal bone sizes from the proximal and distal row dimensions. The correlations in the proximal row were higher compared to the distal row. We established comprehensive size correlations and size rations and found that there exist statistical differences between sex, particularly of the scaphoid. The regression plots and equations we provided will assist surgeons in a more accurate preoperative morphological evaluation for therapy planning and may be used for future anatomically inspired orthopedic biomedical device designs.

Quantitative 3-D CT Demonstrates Distal Row Pronation and Translation and Radiolunate Arthritis in the SNAC Wrist

BACKGROUND

In scaphoid nonunion advanced collapse (SNAC) wrist arthritis, we analyzed the 3-dimensional (3-D) deformity patterns of carpal alignment secondary to scaphoid nonunion and quantified subchondral arthritis by investigating alterations in bone density.

METHODS

We constructed 3-D models of the carpal bones and radius from 51 patients with scaphoid nonunion (nonunion group) and 50 healthy controls (control group). We quantified the differences in 3-D geometric position of the distal carpal row relative to the distal radius in SNAC wrists versus controls. In addition, we assessed the bone density of anatomic regions of interest in the radiocarpal and capitolunate joints relative to the pisiform bone density to characterize degenerative changes in SNAC wrists.

RESULTS

The distal carpal row pronated by a difference of 14° (7.2° versus -6.7°; p < 0.001), deviated ulnarly by a difference of 19° (7.7° versus -11.2°; p < 0.001), shifted dorsally by a difference of 17% of the dorsovolar width of the distal radius (21.0% versus 4.4%; p < 0.001), shifted radially by a difference of 8% of the radioulnar width of the distal radius (13.2% versus 5.3%; p < 0.001), and migrated proximally by a difference of 12% of the lunate height (96.3% versus 108.8%; p < 0.001) in the nonunion group compared with the control group. Additionally, it was found that bone density was greater at the capitolunate joint (capitate head: 140.4% versus 123.7%; p < 0.001; distal lunate: 159.9% versus 146.3%; p < 0.001), the radial styloid (157.0% versus 136.3%; p < 0.001), and the radiolunate joint (proximal lunate: 134.8% versus 122.7%; p < 0.001; lunate fossa: 158.6% versus 148.1%; p = 0.005) in the nonunion group compared with the control group.

CONCLUSIONS

Scaphoid nonunion exhibited a unique deformity pattern and alteration in bone-density distributions. The distal carpal row not only shifted dorsally and migrated proximally but also pronated, deviated ulnarly, and shifted radially. Bone density was greater at the capitolunate joint, the radial styloid, and surprisingly, the radiolunate joint. Our findings give insight into the natural history and progression of arthritis of the SNAC wrist. Additionally, future studies may give insight into whether successful treatment of scaphoid nonunion arrests the progression of arthritis.

LEVEL OF EVIDENCE

Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Does Midcarpal Joint Structure Affect Development of Arthritis in the Wrist

Background  Degenerative wrist arthritis develops in specific patterns because of forces acting on existing structural configurations. The most common pattern of wrist osteoarthritis is scapholunate advanced collapse (SLAC). Other patterns include isolated scaphotrapezial trapezoid (STT) joint and isolated midcarpal or radiolunate joint arthritis. One predictor of degeneration pattern is the structure of the wrist. Questions/Purposes  Our purpose was to evaluate the relationship between midcarpal joint structure and the pattern of degenerative arthritis. We hypothesized that a wrist type 2 will preferentially develop SLAC degeneration. Patients and Methods  We retrospectively evaluated 195 degenerative wrist radiographs. Radiographs were reviewed for lunate/wrist type, degeneration pattern, ulnar variance, radial and volar tilt, inclination, carpal height, scapholunate angle, gap, and presence of thumb carpometacarpal (CMC) joint, STT joint, and midcarpal joint arthritis. Results  We had 158 radiographs with SLAC degeneration and 37 with atypical patterns, 154 type 2 and 41 type 1 wrists. There was a significant correlation between wrist type and the pattern of wrist degeneration ( p  = 0.02). SLAC degeneration developed in wrists with type 2 lunate while isolated midcarpal arthritis was associated with type 1 wrist. Isolated midcarpal joint arthritis was associated with STT arthritis, p  < 0.01. Radial height, inclination, volar tilt, and ulnar variance, and scapholunate gap and angle were not associated with wrist type. Ulnar variance was associated with thumb CMC and STT joint arthritis while radial height was associated with isolated midcarpal joint arthritis. Conclusion  This study found significant relationships between midcarpal joint structure and pattern of degeneration. This contributes to understanding the development of degeneration and can aid in future prevention of arthritis. Level of Evidence  This is a Level IV, diagnostic study.

Relationship Between Carpal Bone Morphology and Distal Radius Fracture Pattern

Abstract Background: In this study, we examined whether carpal bones (lunate, hamate, capitate) morphologies and fourth metecarp-capitate articulation have an effect on the distal radius fracture pattern. Methods: 206 patients who applied to the emergency department with distal radius fracture between 2016-2020 were included in the study. Preoperative and pre-reduction x-ray films of the patients were examined. Lunate, hamate, capitate morphologies and 4.metacarp articulation analyzed and classified. Distal radius fracture types were classified according to AO and Fernandez. The relationship between carpal bone morphology and distal radius fracture type was analyzed. Results: This study consisted of 101 men and 103 women. AO fracture types and carpal bone morphologies (lunate joint type according to Viegas, lunate type according to Zapico, capitate morphology, hamate morphology and capitate-4 metacarpal joint morphology) did not differ significantly (p > 0.05). Fernandez fracture types and carpal bone morphologies (lunate joint type according to Viegas, lunate type according to Zapico, capitate morphology, hamatum morphology and capitate-4.metacarp joint morphology) were compared, there was no significant difference (p > 0.05). Conclusion: As a result, no clear relationship could be demonstrated between carpal bone morphology and distal radius fracture pattern.

The Biomechanical Effects of Simulated Radioscapholunate Fusion With Distal Scaphoidectomy, 4-Corner Fusion With Complete Scaphoidectomy, and Proximal Row Carpectomy Compared to the Native Wrist

PURPOSE

To determine the effect of simulated radioscapholunate fusion with distal scaphoid excision (RSLF+DSE), 4-corner fusion with scaphoidectomy (4-CF), and proximal row carpectomy (PRC) on the wrist's range of motion (ROM), contact pressure, and contact force in a cadaveric model.

METHODS

Ten freshly frozen cadaveric wrists were tested under 4 sequential conditions: native wrist, RSLF+DSE, 4-CF, and PRC. The simulated fusions were performed using two 1.6-mm Kirschner wires. The ROM in the flexion-extension and radioulnar deviation planes was evaluated. Contact area, contact pressure, and contact force were measured at the scaphocapitolunate joint for the RSLF+DSE simulation and radiocarpal joint for the 4-CF and PRC simulations. Mechanical testing was performed using a 35-N uniaxial load and pressure-sensitive film.

RESULTS

The RSLF+DSE and 4-CF groups had a decreased wrist arc ROM compared with the native wrist. The PRC group had a greater wrist arc ROM compared with the RSLF+DSE and 4-CF groups, but compared to the native wrist, it demonstrated a mildly decreased wrist arc ROM. The carpal pressure and contact force were significantly increased in the RSLF+DSE, 4-CF, and PRC groups compared with those in the native wrist. The RSLF+DSE group had the smallest increase in the carpal pressure and contact force, whereas the PRC group had the greatest increase.

CONCLUSIONS

Our study validates previous findings that PRC is motion-conserving but has the greatest contact force, whereas RSLF-DSE and 4-CF may cause a decrease in the ROM but have lower contact forces.

CLINICAL RELEVANCE

Understanding the underlying native wrist biomechanics and alterations following different surgical treatments may assist hand surgeons in their clinical decision making for the treatment of stage II scapholunate advanced collapse.

Functional signals and covariation in triquetrum and hamate shape of extant primates using 3D geometric morphometrics

In this study, we want to investigate the covariation in the shape of two carpal bones, the triquetrum and hamate, and the possible association with locomotor behavior in a broad range of primate taxa. We applied 3D Geometric Morphometrics on a large data set comprising 309 anthropoid primates of 12 different genera. Principal component analyses were performed on the covariance matrix of 18 (triquetrum) and 23 (hamate) Procrustes-aligned surface landmarks. A two-block partial least square analysis was done to test the covariance between triquetrum and hamate shape, without relying on the predictive models implicit in regression analyses. The results show that the carpal shape of quadrupedal anthropoids, which mainly use their wrist under compressive conditions, differs from that of suspensory primates as their wrist is possibly subjected to tensile and torsional forces. Within the hominids, differences in shape also distinguish more terrestrial from more arboreal species. Even within the great apes, we are able to capture shape differences between species of the same genus. In combination with behavioral and biomechanical studies, the results of this research can be used to establish form-function relationships of the primate hand which will aid the functional interpretation of primate fossil remains.

Single-Cut Single-Screw Capitate-Shortening Osteotomy for Kienbock's Disease

Background  Kienbock's disease, in spite of an uncertain natural history, is known to cause lunate compromise, leading to central column collapse, carpal instability, and degenerative arthritis of the wrist. Joint leveling procedures are performed in the early stages of Kienbock's disease to "unload" the lunate. Capitate shortening is the preferred procedure in Kienbock's patients with positive ulnar variance. Description of Technique  We describe the rationale and a simplified technique of capitate shortening in early Kienbock's disease. This is a single-cut osteotomy with single-screw stabilization. Patients and Methods  We have performed this technique in three cases. We present a case of a 26-year-old male who presented with a 1-year history of pain in his right wrist. Radiology performed demonstrated lunate sclerosis. Diagnostic arthroscopy revealed healthy articular surfaces. Single osteotomy capitate shortening was performed with an oscillating saw and fixed with a single cannulated compression screw. A shortening of 1.5mm was obtained with this technique. Results  At 1- to 2-year follow-up, all three patients had considerable pain relief but did not have a complete resolution of pain. There was a significant improvement in function and grip strength. There have been no cases with infection, nonunion, avascular necrosis or a need for a salvage procedure. Conclusion  The simplified technique of capitate shortening is easy to perform, less traumatic to the capitate vascularity, and leads to good short-term functional results.

Translation of 2-Dimensional Wrist Radiographic Measurements to 3-Dimensional CT Scans

Background: Anatomical structure affects function. The morphology of articulations dictates the way forces will travel through the joint. A better understanding of the structure and function of the wrist will enhance our ability to diagnose and treat wrist conditions. Two wrist types have been described based on the morphology of the midcarpal joint. Biomechanically it is important to see if these 2-dimensional (2D) observations reflect articular contact areas. Our purpose was to assess the correlation between measurements performed on wrist radiographs (2D) to measurements performed on 3-dimensional (3D) computed tomography (CT). Methods: Retrospective review of a database of normal wrist radiographs and corresponding normal CT scans. Only imaging pairs with normal carpal alignment and technically optimal imaging were included. Evaluations included lunate, capitate and wrist type, capitate circumference, percent capitate circumference and volume that articulates with the lunate, scapholunate ligament, scaphoid, hamate, trapezoid, base of the index and middle and ring metacarpal bones. Results: Midcarpal joint radiographic measurements were positively correlated with measurements on CT scans. Correlations were 0.51 for capitate type and 0.71 for lunate type with both p < 0.001. Percent contact of the lunate with the hamate: r was 0.74 p < 0.001. Using logistic regression analysis, percent lunate-hamate contact on CT was a significant predictor of radiographic lunate type 2 p < 0.001. Percent contact area between lunate and hamate > 7.8% on CT scan achieved a sensitivity of 100% and specificity 79.4% for a type 2 lunate. Conclusions: 1) Good correlations found between CT and plain radiographs in lunate type, capitate type, and midcarpal joint contact support the use of plain radiographs to describe contact between the carpal bones in the clinical setting. 2) The retrospective nature of this study limited the technical quality of the measurements. Volumetric analysis may aid in a more exact evaluation of surface contact area.

Osteonecrosis of the Lunate: Kienböck Disease

Kienböck disease, osteonecrosis of the lunate, is a well-known but poorly understood complication seen by hand surgeons. This review presents the background and important patient-specific parameters of the disease and reviews the numerous treatment options that exist for the disease.

Midcarpal Structure Effect on Force Distribution through the Radiocarpal Joint

Background  Wrist structure is complicated by distinct anatomical patterns. Previous studies defined radiographic wrist types based on lunate and capitate shape within the midcarpal joint. We hypothesized that these disparate structural patterns will transfer forces differently through the wrist. Objective  This study aims to correlate force transferred to the distal radius and ulna with morphological measurements in cadaver arms. Methods  Radiographs from 46 wrists, previously tested for force transfer between the radius and ulna, were examined. The percentage of compressive force through the distal ulna was determined by mounting load cells to the radius and ulna, while 22.2 Newton (N) tensile forces were individually applied to multiple tendons. Each wrist was tested in a neutral flexion-extension and radial-ulnar deviation position. Results  Wrist type and lunate type were associated with percentage of force transfer through the ulna ( p  = 0.002, p  = 0.0003, respectively). Percentage of force transfer was correlated with capitate circumference ( p  = 0.02, r  = 0.34). Conclusions  This study supports distinct force transfer between morphological wrist types. Clinical Relevance  Understanding the mechanical significance of different structural variations in the wrist bones will improve our ability to understand wrist function and the distinctive development of wrist pathology. Level of Evidence  This is a Level II study.

The Vascular Anatomy of the Scaphoid: New Discoveries Using Micro-Computed Tomography Imaging

PURPOSE

The purpose of this study was to investigate the intraosseous vascular anatomy of the scaphoid using recent advances in micro-computed tomography (micro-CT) imaging and 3-dimensional reconstruction. We also studied the effect of scaphoid shape and screw position on the intraosseous vascular structure.

METHODS

Thirteen upper extremities were injected with a contrast agent. The scaphoid bones were extracted and scanned using a micro-CT scanner. The vascular impact of screw insertion at various axes through the scaphoid was calculated and compared using the generated 3-dimensional models. The specimens were 3-dimensionally-printed and the morphology was assessed according to bone dimensions. A relationship between the internal vascular patterns and these morphological features was determined.

RESULTS

All specimens received vascular inflow from the dorsal ridge forming a vascular network that supplied an average of 83% of the bone's volume. This network was supplemented in 4 specimens with volar vessels entering at the waist. Another network was identified, created by vessels entering volarly at the tubercle, which supplied the remainder of the scaphoid. One specimen did not receive any vessels at the tubercle. With regards to screw placement, screws placed in the central axis were the least disruptive to the internal vascularity, followed by the antegrade (dorsal) insertion axis. Two morphological bone types were identified: type I or full scaphoids and type II or slender scaphoids. Type I possessed a more robust internal vascular network than type II scaphoids.

CONCLUSIONS

This study identifies 2 distinct types of scaphoid morphology with 1 of them having a less robust blood supply, which may prove to be related to development of nonunion, avascular necrosis, or Preiser disease. Central axis and antegrade (dorsal) screw fixation may be least disruptive to the internal blood supply.

CLINICAL RELEVANCE

Safer fixation of the scaphoid bone may be achieved by knowledge of intraosseous vascular patterns.

Bony anatomy of the third metacarpal and relationship with the capitate: a computed tomography study

PURPOSE

The purpose of this study was to accurately establish the anatomical variability of the third metacarpal, its medullary canal, and the relationship with the capitate in the context of high rates of component loosening still seen in total wrist arthroplasty.

METHODS

CT scans of a 100 hands (age: 41 ± 14 years (range: 16-71 years); male/female ratio: 53/47) were studied to establish the detailed anatomy of the third metacarpal and the capitate.

RESULTS

Although the shape of the third metacarpal and the angles formed with the capitate were highly variable, the third metacarpal length was longer in males (p < 0.001), the proximal cortical bone was thicker (p < 0.001) and the sagittal metacarpal-capitate axis offset was greater (p = 0.01). A relationship was found between the total length of the metacarpal and the distance to the isthmus from the base (r = 0.63; p < 0.0001) which was unaffected by gender. No age-related relationships were significant.

CONCLUSION

The anatomy of the third metacarpal and capitate varies considerably more than has been alluded to in current wrist arthroplasty literature. Differences between males and females can likely be attributed to hand size. The distance of the isthmus from the base can be predicted from the total length of the metacarpal with a standard error of 1.9 mm.

The Effect of Radioscapholunate Fusion With and Without Distal Scaphoid and Triquetrum Excision on Capitolunate Contact Pressures

PURPOSE

To determine the effects of motion-increasing modifications to radioscapholunate (RSL) arthrodesis on capitolunate contact pressure in cadaveric wrist specimens.

METHODS

Ten fresh-frozen cadaveric wrists were dissected of all superficial soft tissue, potted in polymethyl-methacrylate, and the carpus exposed via a ligament-sparing capsulotomy. An RSL arthrodesis was simulated using 2 2.4-mm distal radius plates with locking screws. The distal scaphoid pole and triquetrum were removed with an osteotome and rongeur, respectively. Contact area, pressure, and force were measured in the capitolunate joint during the application of a 35-N uniaxial load using pressure-sensitive film. Measurements were obtained before and after simulated RSL fusion, following distal scaphoidectomy and after triquetrectomy.

RESULTS

The combination of RSL fusion with distal scaphoid excision (DSE) increased contact forces in the capitolunate joint by 50% over controls. An RSL fusion, and RSL fusion with DSE and triquetrum excision (TE), exhibited intermediate levels of contact force between controls and RSL fusion with DSE. Capitolunate contact pressures were similar between all experimental groups. Contact area in the capitolunate joint increased by 43% after RSL fusion with DSE over intact specimen controls. Lastly, contact area in wrists with RSL fusion, and RSL fusion with DSE and TE, were elevated, but not significantly different from intact controls.

CONCLUSIONS

A DSE performed at the time of RSL fusion results in increased midcarpal joint contact force and area, with resultant contact pressures unchanged. Triquetrectomy, which has been previously shown to improve range of motion, did not increase contact forces in the capitolunate joint.

CLINICAL RELEVANCE

If a surgeon is contemplating performing an RSL arthrodesis with DSE, we recommend adding a triquetrectomy to improve motion because this does not add to the potentially deleterious effects of increased midcarpal contact force.

Arthroscopic Interposition Tendon Arthroplasty for Stage 2 Scapholunate Advanced Collapse

PURPOSE

To report and analyze the functional outcomes of arthroscopic interposition tendon arthroplasty (AITA) in stage 2 scapholunate advanced collapse (SLAC).

METHODS

Sixteen patients with stage 2 SLAC who underwent AITA between 2009 and 2014 with a minimum of 24-month follow-up were retrospectively evaluated. Medical records were assessed for preoperative and postoperative range of motions, grip strength, visual analog scale, disabilities of the arm, shoulder, and hand (DASH) score, scapholunate angle, and scaphoid fossa-to-scaphoid space.

RESULTS

After exclusion of 2 patients, 14 patients were available for this study. At final follow-up, improvements were found for the following variables: extension (preoperative mean, 49.29°; VS postoperative mean, 61.07°; P = .025, 95% confidence interval [CI], 1.74-21.85), radial deviation (preoperative mean, 6.43°; postoperative mean, 17.14°; P < .001, 95% CI, 6.06-15.36), grip strength (preoperative mean, 18.93 kg; postoperative mean, 29.64 kg; P < .001; 95% CI, 6.81-14.61), visual analog scale (preoperative mean, 8.07; postoperative mean, 2.50; P < .001; 95% CI, -6.52 to -4.61), and DASH (preoperative mean, 60.39; postoperative mean, 10.28; P < .001, 95% CI, -43.04 to -57.28), scapholunate angle (preoperative median, 67.50°; postoperative median, 55.00°, P = .002, Z = -2.831), and scaphoid fossa-to-scaphoid space (preoperative median, 0.00 mm; postoperative median, 1.00 mm; P < .001, Z = -3.145). There was no improvement in flexion (preoperative mean, 40.00°; postoperative mean, 50.00°^;P = .025; 95% CI, -4.45 to -24.45), ulnar deviation (preoperative median, 25.00°; postoperative median, 30.00°^;P = .063, Z = -2.060), or flexion-extension arc (preoperative mean, 89.28°; postoperative mean, 111.07°; P = .067; 95% CI, -1.79 to -45.36) following AITA. Nine of 13 patients were satisfied with the procedure, 3 were moderately satisfied, and 1 was not satisfied.

CONCLUSIONS

Arthroscopic interposition tendon arthroplasty is an acceptable procedure for stage 2 SLAC. This procedure preserves motion, yields acceptable functional outcome, and reduces pain.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Capitate and Lunate Morphology in Normal Wrist Radiographs-A Pilot Study

BACKGROUND

Morphology may provide the basis for the understanding of wrist mechanics.

METHODS

We used classification systems based on cadaver dissection of lunate and capitate types to evaluate a normal database of 70 wrist radiographs in 35 subjects looking for associations between bone shapes. Kappa statistics and a log-linear mixed -effects model with a random intercept were used.

RESULTS

There were 39 type-1, 31 type- 2 lunates, 50 spherical, 10 flat and 10 V-shaped capitates. There was a significant difference in lunate and capitate shape between the hands of the same individual p <0.001. This may be due to different loads on the dominant vs. nondominant hands in the same individual.

CONCLUSION

Further study to better understand the development of radiographic parameters of the midcarpal joint may aid in our understanding of the morphology and mechanics of the wrist.

Distinct Wrist Patterns Founded on Measurements in Plain Radiographs

Background  In joints, structure dictates function and consequently pathology. Interpreting wrist structure is complicated by the existence of multiple joints and variability in bone shapes and anatomical patterns in the wrist. Previous studies evaluated lunate and capitate shape in the midcarpal joint, and two distinct patterns have been identified. Purpose  Our purpose was to further characterize the two wrist patterns in normal wrist radiographs using measurements of joint contact and position. Our hypothesis was that we will find significant differences between the two distinct anatomical patterns. Patients and Methods  A database of 172 normal adult wrist posteroanterior (PA) radiographs was evaluated for radial inclination, height, length, ulnar variance, volar tilt, radial-styloid-scaphoid distance, and lunate and capitate types. We measured and calculated percent of capitate facet that articulates with the lunate, scapholunate ligament, scaphoid, and trapezoid. These values were compared between the wrist types and whole population. Results  Type-1 wrists (lunate type-1 and spherical proximal capitate) were positively associated with a longer facet between capitate and distal lunate ( p  = 0.01), capitate and base of middle metacarpal ( p  = 0.004), and shorter facet between the capitate and hamate ( p  = 0.004). The odds ratio of having a type-1 wrist when the interface between the capitate and lunate measures >8.5 mm is 2.71 (confidence interval [CI] 1.07, 6.87) and when the line between the capitate and the base of middle metacarpal >9.5 mm is 3.5 (CI 1.38, 9.03). Conclusion  We characterized the two-wrist patterns using intracarpal measurements. Translating these differences into three-dimensional contact areas may help in the understanding of biomechanical transfer of forces through the wrist. Level of Evidence  This is a Level II, diagnostic study.

Evaluation of midcarpal capitate contact mechanics in normal, injured and post-operative wrists

BACKGROUND

Scapholunate ligament injury is a commonly occurring carpal ligament injury. Pathology associated with scapholunate ligament injury depends on several factors such as the time after injury, type of injury (instability) and the development of osteoarthritis. The aim of this study was to investigate and compare contact mechanics in the lunocapitate and scaphocapitate joints in the normal, injured (scapholunate dissociation) and repaired (postoperative) wrist.

METHODS

Four human subjects with scapholunate ligament dissociation participated in this study. MR images of normal (contralateral), injured and postoperative wrists were obtained during relaxed condition and during active light grasp. Relaxed MR images were used to construct model geometry (bones with cartilage) for the capitate, lunate and scaphoid. Kinematic transformations were obtained by using image registration between the unloaded and functionally loaded image sets. Joint surface contact mechanics were then calculated.

FINDINGS

All contact measures (contact force, pressure, mean pressure and area) tended to increase with injury in both articulations. A significantly higher contact area was found in the injured scaphocapitate joint compared to normal. A significant increase in peak pressure was observed in the postoperative state compared to normal.

INTERPRETATION

Injury to the scapholunate ligament increased contact measures, suggesting a risk for onset of osteoarthritis in both the scaphocapitate and lunocapitate joints. Surgical repair appeared to restore most measures of contact mechanics to near normal values, more so for the lunocapitate joint when compared to scaphocapitate joint. The elevated postoperative peak pressures indicate the difficulty to fully restore joint mechanics.

Long-term outcomes of proximal row carpectomy: A series of 62 cases

The aim of this study was to determine and analyze the functional and radiographic outcomes after proximal row carpectomy (PRC). We hypothesized that this surgery could restore wrist mobility and function in case of radiocarpal osteoarthritis or severe carpal trauma. Sixty-two patients who had undergone PRC were included in this study: 44 patients with wrist osteoarthritis (11 SNAC, 24 SLAC, 3 Kienböck's disease, 6 other) and 18 patients with severe carpal trauma. Each patient underwent clinical (pain, range of motion, grip strength, functional scores) and radiographic evaluations. At the latest evaluation after a mean of 11.8 years, 15 patients (24.2%) required revision total wrist arthrodesis surgery in a median of 22 months (range, 6-179) because of disabling pain and lack of strength. The failure was statistically correlated with being young and a manual laborer. The range of motion and strength of the operated wrist were 61.5% and 70%, respectively, compared to the contralateral side. PRC remains a reliable procedure for treating wrist arthritis and severe carpal trauma. However, manual activity and being under 50years of age can lead to an early salvage procedure such as total arthrodesis of the wrist. In this subset of the population, another alternative must be considered.

Clinical outcomes of proximal row carpectomy by preoperative midcarpal joint morphological classification: Viegas type I versus type II

The midcarpal joint can be classified into two anatomical types - Viegas type I and Viegas type II - based on the absence or presence of a medial facet for the hamate on the lunate (lunohamate facet). Type I is associated with a round capitate shape, which theoretically allows better congruence with the lunate fossa of the distal radius following proximal row carpectomy (PRC). This morphological feature has never been considered as a predictive factor of clinical outcome for this surgical procedure. This study aimed to compare the clinical and radiological outcomes of the two Viegas types following PRC. A retrospective single-center study was carried out on patients who underwent PRC for wrist osteoarthritis. Minimum follow-up was 2 years. Lunate type was determined based on preoperative CT arthrography. The clinical evaluation included range of motion (ROM) and strength as well as the functional DASH, Mayo Wrist scores and a VAS for pain. The outcome of radiocapitate osteoarthritis was assessed on plain radiographs. Forty patients were reviewed with a mean follow-up of 57 months. Twenty-one Viegas type I and 19 Viegas type II were identified on preoperative CT arthrography. The etiologies included 23 SLAC wrists (12 Viegas type I, 11 type II), 8 SNAC wrists (4 Viegas type I, 4 type II), 6 cases of Kienböck's disease (3 type IIIa, 3 type IIIb with 3 Viegas type I and 3 type II), 1 Preiser's disease and 2 cases of transscaphoid perilunate dislocation of the carpus. Patients with a Viegas type I lunate had significantly greater flexion-extension ROM: 83.5° vs. 71° (P=0.04) and radial deviation: 12° vs. 7° (P=0.013) than those with Viegas type II. However, three cases of complex regional pain syndrome (CRPS) were reported in the Viegas type II group vs. zero in the Viegas type I group. There were no differences between the two groups in terms of strength, functional scores or VAS pain. The outcome of radiocapitate osteoarthritis was similar in both groups. Considering the number of CRPS cases in the Viegas type II group and similar functional results in both groups, the worse outcomes of the Viegas type II patients in terms of ROM cannot be considered as clinically relevant. This comparative study does not provide a reasonable basis for concluding that Viegas type I patients are better candidates for PRC than Viegas type II patients.

Anatomical Wrist Patterns on Plain Radiographs

BACKGROUND

Interpreting the structure in the wrist is complicated by the existence of multiple joints as well as variability in bone shapes and anatomical patterns. Previous studies have evaluated lunate and capitate shape in an attempt to understand functional anatomical patterns.

OBJECTIVE

The purpose of this study was to describe anatomical shapes and wrist patterns in normal wrist radiographs. We hypothesized that there is a significant relationship in the midcarpal joint with at least one consistent pattern of wrist anatomy.

METHODS

Seventy plain posteroanterior (PA) and lateral wrist radiographs were evaluated. These radiographs were part of a previously established normal database, had all been read by a radiologist as normal, and had undergone further examination by 2 hand surgeons for quality. Evaluation included: lunate and capitate shape (type 1 and 2 lunate shape according to the classification system by Viegas et al.), ulnar variance, radial inclination and height, and volar tilt.

RESULTS

A significant association was found between lunate and capitate shape using a dichotomal classification system for both lunate and capitate shapes (p=0.003). Type 1 wrists were defined as lunate type1and a spherical distal capitate. Type 2 wrists had a lunate type 2 and a flat distal capitate. No statistically significant associations were detected between these wrist types and measurements of the radiocarpal joint.

CONCLUSION

There was a significant relationship between the bone shapes within the midcarpal joint. These were not related to radiocarpal anatomical shape. Further study is necessary to better describe the two types of wrist patterns that were defined and to understand their influence on wrist biomechanics and pathology.

Proximal row carpectomy on manual workers: 17 patients followed for an average of 6 years

Proximal row carpectomy (PRC) is indicated for the treatment of SNAC or SLAC wrist with preservation of the midcarpal joint. Our hypothesis was that PRC is not appropriate for treating advanced wrist osteoarthritis in patients who carry out heavy manual work. Twenty-three PRCs were performed on 21 patients, 5 women and 16 men with an average age of 54 years (33-77). All patients performed manual work; 11 of them performed heavy manual work. Etiologies were: SLAC wrist in 14 cases (2 stage III, 11 stage II, and 1 stage I) and SNAC wrist in 9 cases (6 stage IIIB and 3 stage IIB). At an average 75 months' follow-up (24-153), five patients were lost to follow-up. Radiocarpal arthrodesis was performed in one patient 10 years after the PRC. In the 17 remaining patients (18 wrists), pain (VAS) averaged 2.2, with residual pain of 5. Flexion-extension range was similar to preoperative levels (67% of contralateral wrist). Wrist strength was decreased by 34% compared to preoperative. The QuickDASH score averaged 26 points and the PRWE 20 points. Radiocapitate distance decreased by 0.3mm on average with joint line narrowing in 6 patients. The carpal translation index was 0.33mm, which was unchanged relative to preoperative values. Three patients had work-related limitations that required retraining and one patient had to be reassigned. PRC preserved the preoperative range of motion and reduced pain levels. However, significant loss of strength was observed, resulting in 23% of manual workers needing retraining or reassignment.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Carpal Kinematics and Kinetics

The complex interaction of the carpal bones, their intrinsic and extrinsic ligaments, and the forces in the normal wrist continue to be studied. Factors that influence kinematics, such as carpal bone morphology and clinical laxity, continue to be identified. As imaging technology improves, so does our ability to better understand and identify these factors. In this review, we describe advances in our understanding of carpal kinematics and kinetics. We use scapholunate ligament tears as an example of the disconnect that exists between our knowledge of carpal instability and limitations in current reconstruction techniques.

Factors associated with improved outcomes following proximal row carpectomy: a long-term outcome study of 144 patients

We conducted a review of 144 consecutive patients who underwent proximal row carpectomy from 1967 to 2010 for the diagnosis of wrist arthritis. At a mean follow-up of 13.4 years, patients experienced good pain relief with preservation (but not improvement) of wrist motion. A total of 17 patients (12%) required revision surgery at an average of 44.6 months. Improved pain, function, and survival outcomes were seen in those who underwent proximal row carpectomy after the age of 40, had a preoperative diagnosis of Kienbock's disease, who underwent a concomitant neurectomy procedure, patients who were non-labourers, and patients who underwent surgery after 1990. Although 45% of patients developed moderate to severe radiocapitate arthrosis postoperatively, these findings did not correlate with clinical outcomes or risk of revision surgery. Patients with type II lunate and type II and III capitate shapes had higher rates of postoperative radiocapitate arthrosis.

LEVEL OF EVIDENCE

III, Prognostic.

Negative Ulnar Variance and Kienböck Disease

PURPOSE

To test the primary null hypothesis that there is no difference in mean ulnar variance (UV) scaled to the length of the capitates between 166 wrists with Kienböck disease and an equal number of matched controls and to test the secondary null hypothesis that mean scaled UV does not vary based on age, sex, or race in both Kienböck and control wrists.

METHODS

Ulnar variance was measured on posteroanterior radiographs of the wrist as the distance between a line through the midpoint between the volar and the dorsal edges of the ulnar margin of the radius and a line tangential to the most distal aspect of the carpal surface of the head of the ulna, both perpendicular to the longitudinal axis of the radius. Measurement of UV was scaled to the length of the capitate, resulting in a UV to capitate height (UV:CH) ratio.

RESULTS

We found a significant difference in mean UV:CH ratio between patients with Kienböck disease and a control group matched by age, sex, race, and limb. The prevalence of negative UV was high in both patients with Kienböck disease and matched controls. There were no differences in mean UV:CH ratio with respect to age, sex, or race among patients with Kienböck disease or matched controls.

CONCLUSIONS

The precise role of ulna minus in the development of Kienböck disease remains uncertain and unanswered, given that many patients with Kienböck disease have neutral or positive UV. In addition, a large proportion of the normal population has negative UV, whereas Kienböck disease is rare.

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.

Radiocapitate congruency as a predictive factor for the results of proximal row carpectomy

PURPOSE

To evaluate whether the congruency between the joint surfaces of the lunate fossa of the distal radius and the proximal capitate might be a prognostic factor for functional, clinical, or radiographic results after proximal row carpectomy (PRC).

METHODS

After reconstructing the computed tomographic arthrogram of patients with PRC, we evaluated the shape of the proximal capitate by measuring the radius of curvature of the tip of the capitate. The congruency of the future radiocapitate joint was then evaluated by the radiocapitate index in the frontal and sagittal planes. This was calculated by dividing the radius of curvature of the tip of the capitate by the mean radius of curvature of the lunate fossa. We determined the relationship between these morphological results and the functional (Disabilities of the Arm, Shoulder, and Hand [DASH] score, Mayo Wrist score, and pain relief), clinical (mobility and strength) and x-ray results (radiocapitate arthrosis).

RESULTS

A total of 27 patients were reviewed at a mean follow-up of 59 months. The shape of the proximal capitate did not affect outcomes. In the frontal plane, a better radiocapitate congruency was significantly associated with an increase in wrist flexion and better functional results for the DASH. There was a non-significant relationship between congruency and improvement of Mayo Wrist score and pain relief. In the sagittal plane, the DASH score tended to improve when congruency was better.

CONCLUSIONS

The shape of the capitate was not a prognostic factor for functional outcome after PRC. The radiocapitate index seems more relevant in predicting results at last follow-up.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic II.

Isolated lunocapitate osteoarthritis-an alternative pattern of osteoarthritis

Introduction Osteoarthritis (OA) in the wrist usually develops in a pattern described as scapholunate advanced collapse (SLAC). We observed an alternative pattern of OA that involves the lunocapitate joint in isolation with minimal involvement of the radioscaphoid articulation. Case Series The series was observed from a series of 100 wrist radiographs that were retrospectively reviewed. In order to characterize the alternative pattern of OA, we compared demographic data, presentation, and physical and radiographic examination characteristics between the patients with lunocapitate OA and SLAC wrists. Fifteen radiographs showed OA, nine had a SLAC pattern, and six had lunocapitate OA. The demographics were similar, but the clinical presentation was different. The patients with lunocapitate OA had less tenderness over the snuffbox (P < 0.03), and a lower percentage of a positive scaphoid shift test (P <  0.005). Isolated lunocapitate OA had a higher association with scaphotrapeziotrapezoidal (STT) arthritis (P < 0.004). The SLAC group had an increased scapholunate gap (P = 0.0003). Discussion  The presentation of lunocapitate OA differs from SLAC wrist in a number of ways. Further study is necessary to understand the clinical implications of this pattern. Level IV evidence Case series.

Osteoarthritis of the wrist

This article reviews pathogenesis and treatment of wrist osteoarthritis. Because there is no cure for osteoarthritis, treatment is directed at symptomatic relief. Surgical treatment is reserved for patients who have failed nonoperative modalities. This article reviews the surgical treatment of wrist osteoarthritis with an emphasis on selection of the appropriate procedure. Literature guiding surgical treatment with patient outcomes is reviewed.

A hand therapy protocol for the treatment of lunate overload or early Kienbock's disease

We describe a hand therapy protocol aimed at unloading the wrist and increasing blood supply to the wrist, specifically to the lunate. The protocol was used in a series of patients with clinical radial wrist pain, dysfunction and changes on wrist imaging studies. The patients were not candidates for surgical treatment. Application of the therapy protocol improved objective and subjective parameters such as pain and motion, and may provide a viable treatment option for patients with lunate overload or early Kienbock's disease that are not candidates for surgery.

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 capitate morphology on contact biomechanics after proximal row carpectomy

PURPOSE

Proximal row carpectomy (PRC) is used as a treatment for a variety of wrist pathologies to maintain motion and to improve strength and decrease pain. Several studies have looked at how PRC alters wrist characteristics, although they did not provide an explanation for the variability observed in outcomes. Studies have classified the capitate into 3 unique types: round, V-shaped, or flat. We hypothesized that these differences in morphology could affect the contact biomechanics between the radius and the capitate after PRC.

METHODS

A total of 14 cadaveric wrists underwent PRC. They were classified by capitate morphology and then loaded to 200 N in a neutral position, flexion, and extension. We measured contact area, contact pressure, and location using pressure-sensitive film in all 3 positions and compared their morphology types.

RESULTS

Nine wrists had a round-type capitate, 4 had a V-shaped capitate, and 1 had a flat capitate, which we excluded from statistical analysis. Comparing round and V-shaped types, we found no differences in contact area, pressure, or location in any wrist position For the V-shaped capitates, there was increased contact pressure in flexion and extension compared with the wrist in neutral. Center of pressure translated dorsal and radial in flexion to volar and ulnar in extension for all types.

CONCLUSIONS

When we compared V-shaped and round-type capitates, we found no significant differences in contact characteristics of the wrist after PRC. There were some differences in contact pressure for V-shaped capitates in various wrist positions.

CLINICAL RELEVANCE

Differences between round and V-shaped capitates do not appear to affect contact biomechanics after PRC. Thus, these 2 capitate shapes may not necessarily be a factor in the decision-making process to perform PRC.

Long-term outcomes of proximal row carpectomy: a systematic review of the literature

Purpose Proximal row carpectomy is a well-established technique for the management of wrist arthritis; however, patient selection and long-term durability of proximal row carpectomy is still a matter of controversy. Hence, we conducted a systematic review of the English literature to determine the best evidence on long-term outcomes following proximal row carpectomy. Methods A MEDLINE search using the term "proximal row carpectomy" was performed. A total of 192 studies were identified. All studies with 10 or more years of follow-up were included in the review. Data extracted included patient demographics, indications for surgery, previous surgery, outcome assessment, and information on complications and failures. Results A total of 147 patients from six studies met the inclusion criteria and were included in the study. The majority of patients were male and involved in manual labor. There was no significant difference between the preoperative and long-term postoperative motion. The weighted mean for postoperative grip strength was 68.4% compared with the contralateral side. Disabilities of the arm, shoulder, and hand; patient-rated wrist examination; and Mayo wrist scores were comparable to those reported for four-corner arthrodesis. There were 21 failures (14.3%) requiring re-operation. Failures were not associated with a specific preoperative diagnosis but distributed among patients with Kienböck disease, scaphoid nonunion advanced collapse, and scapholunate advanced collapse arthritis. Conclusions This systematic review confirms the long-term durability of proximal row carpectomy when used for the treatment of wrist arthritis. Although radiocapitate arthritis develops over time in most patients, the clinical significance of this finding is undetermined and does not necessarily correlate with failure of proximal row carpectomy. Poorer long-term outcomes are likely to result in patients engaged in heavy manual labor, whereas better outcomes may be obtained in patients undergoing proximal row carpectomy for trauma or earlier-stage Kienböck disease.

Kienböck disease

Kienböck disease, or osteonecrosis of the lunate, is a progressive disease process that can lead to wrist pain and dysfunction. Although it was described over 100 years ago, and advances have been made in understanding this disease, the precise etiology remains uncertain. Anatomic, mechanical, vascular, and traumatic factors have been suggested to contribute to the disease. The natural history is unknown, and radiographic and clinical findings do not always correlate. Progress has been made in recognizing the progression of the avascular process and its deleterious effects on wrist mechanics. Initial treatment is nonsurgical, and it remains unclear whether surgical intervention results in improved outcomes over nonoperative treatment. Traditional surgical procedures such as radial shortening osteotomy and proximal row carpectomy have been shown to be reliable treatment options for relieving pain and improving function. Newer procedures such as pedicled bone grafts from the distal radius may improve direct revascularization of the lunate in earlier stages of the disease, potentially arresting the progression of collapse. Additional data are necessary to determine with certainty whether this type of procedure represents an improvement over the traditional treatment alternatives. Kienböck disease remains a challenging problem for hand surgeons.

Long-term outcomes of proximal row carpectomy: a minimum of 15-year follow-up

INTRODUCTION

Proximal row carpectomy (PRC) is a popular procedure for the treatment of wrist arthritis; however, the long-term clinical outcomes of this procedure are not well-characterized. The purpose of this study was to evaluate long-term results with PRC and to identify factors that may improve clinical outcomes.

METHODS

A retrospective study was performed on all patients who underwent proximal row carpectomy between January 1967 and January 1992. Medical records and available radiographs were reviewed. The Disabilities of the Arm, Shoulder and Hand, and Patient Rated Wrist Exam, as well as hand motion diagrams were sent to all surviving patients. The contralateral extremity was used as a control. Data was analyzed using multivariant analysis and a Student's t test.

RESULTS

Eighty-one patients underwent PRC. Average age at the time of surgery was 41 years. Average follow-up was 19.8 years. Sixty-one patients responded to the questionnaires. On final follow-up, wrist motion and grip strength were not significantly different from preoperative values. Radiographic follow-up beyond 2 years revealed joint narrowing and arthritic changes within the radiocapitate joint. Forty-six patients (74%) were not satisfied with the results of their surgery due to persistent pain or inability to return to previous occupational activities. Fifty-two patients required daily pain medication for wrist pain. Twelve patients had undergone a wrist arthrodesis.

CONCLUSIONS

Post-operative motion and grip strength values following PRC appear to remain stable over time. Surgical failure rates with conversion to wrist fusion occurred early within the post-operative follow-up. Many patients continued to complain of pain requiring daily medication and were unable to return to manual labor type jobs. The results of this study suggest that long-term patient satisfaction following PRC can be poor and the surgeon may wish to consider alternative treatment options for younger patients and those with high-demand jobs.

Scaphoid kinematics before and after scaphotrapeziotrapezoidal ligament section. Assessment by radiostereometric analysis and computed tomography in a cadaver study

The purpose of this study was to measure changes in scaphoid kinematics after division of scaphotrapeziotrapezoidal ligaments, with the intention of determining a clinical measure that could be detected by computed tomography. Twelve freshly frozen cadaver upper extremities were marked with tantalum beads and fixed in positions of neutral, 30° extension, and 40° ulnar deviation. Stereoradiographs for bone migration analysis by radiostereometric analysis and computed tomography scans for visible assessment were obtained before and after scaphotrapeziotrapezoidal ligament section. After ligament resection there was a scaphoid supination of 5° and a small (less than 1 mm) radial, distal, and dorsal translation of the distal pole in 30° of wrist extension. In computed tomography reconstructions, the ligament section appeared as a 1 to 2 mm gap in the scaphotrapeziotrapezoidal corner, with loss of articulation between the distal scaphoid pole and the trapezoid bone and increased scaphoid flexion.

Biomechanics of the wrist after proximal row carpectomy in cadavers

We investigated the biomechanics of the radiocapitate joint after a proximal row carpectomy in six fresh-frozen cadaver wrists using super-low-pressure-sensitive film on a material testing system. The average pressure within the lunate fossa increased significantly from 23.2 to 136.4 N/cm(2) with a sharp decrease in the contact area from 2.08 to 0.30 cm(2) after a proximal row carpectomy. The cartilage of the proximal capitate had four sub-facets and therefore was not as smooth as the normal proximal lunate. We found that the wrist was overloaded after a proximal row carpectomy and the main cause was the anatomical mismatch of the radiocapitate articulation.

Imaging recognition of morphological variants at the midcarpal joint

PURPOSE

To compare the imaging methods for identifying the various morphological variations of the articular surfaces at the midcarpal joint.

METHODS

Thirteen cadaveric wrists were examined by plain neutral anteroposterior radiographs; 2-dimensional computed tomography (CT); 3-dimensional CT reconstruction, and 3-tesla magnetic resonance imaging (MRI). Carpal measurements were performed, and the parameters that defined the scaphoid, lunate, hamate, and capitate morphological types were investigated, with dissection being used as the definitive measure of morphology. The dissection findings were compared to the results of each imaging technique to determine the accuracy of morphological determination from each technique.

RESULTS

Lunate type was the most accurately identified morphological variant amongst all imaging techniques. Lunate type was most accurately determined from coronal MRI. A lunate with a small, cartilaginous ulnar facet (intermediate type) could be differentiated only by coronal MRI and dissection. Scaphoid type could not be determined accurately using any of the imaging modalities described. Capitate type was most accurately determined from coronal MRI. However, flat and spherical-type capitates could not be routinely differentiated from V-shaped capitates. Hamate type was most accurately determined from 3-dimensional CT reconstruction.

CONCLUSIONS

Accurate identification of carpal bone morphology is required to improve our understanding of carpal mechanics and pathology. Not all morphological features can be identified radiographically. Direct visualization is required to differentiate types of scaphoid, and to differentiate V-type capitates. MRI provides the most accurate identification of lunate type, and 3-dimensional CT provides the best method of differentiating hamate types.