Capitate Head Research Articles

Pyrocarbon Interposition after Capitate Head Resection

Background Isolated lunocapitate disease is a rare situation. It includes both capitolunate arthritis and osteonecrosis of the capitate head. The management of this pathology is not defined yet. Case Description We treated three patients by resection of the capitate head and interposition of a so-called capitolunate Pi(2) implant (Tornier, BioProfile, Grenoble, France). We reported encouraging results at average follow-up of 4.8 years. Literature Review Several procedures have been reported in this indication. All suffer from lack of follow-up. Four-corner fusion seems to be the most reliable solution at the expense of wrist stiffness. Clinical Relevance case series.

Technique: Osteochondral Grafting of Capitate Chondrosis in PRC

Background Proximal row carpectomy (PRC) is a useful treatment option for wrist arthritis, but the operation is contraindicated when there is arthritis of the capitate head. We describe a technique that involves resurfacing of a capitate that has focal chondrosis, using an osteochondral graft harvested from the resected carpal bones. Materials and Methods PRC patients who had a focal area of capitate chondrosis underwent osteochondral grafting of the capitate. Pre- and postoperative pain level, employment status, motion, grip strength, and Modified Mayo Wrist Scores (MMWS) were assessed. Postoperative Disability of the Arm, Shoulder, and Hand (DASH) scores were also calculated. Description of Technique The articular surface of the capitate is assessed for need for grafting. The proximal row is resected with the lunate removed intact. The arthritic area is prepared. The graft is taken from the lunate and placed in the prepared site of the capitate. Results Eight patients (average age of 53 years) were followed for 18 months. Pain: Preoperatively, moderate to severe in 7 patients; postoperatively, mild to no pain in 7 patients. Motion: Preoperative, 84° (74% of the contralateral side); postoperative 75° (66%). Grip Strength: Preoperative, 29 kg (62%); postoperative, 34 kg (71%). Mayo Wrist Score: Preoperative, 51 (poor); postoperative, 68 (fair). Average postoperative DASH score was 19.5. Follow-up radiographs showed that 75% of patients had mild to no degeneration. Conclusions Osteochondral grafting in PRC offers satisfactory results in terms of pain relief, return to work, motion, and grip strength. Level of Evidence Therapeutic IV, Case series.

Chronic transscaphoid, transcapitate perilunate fracture dislocation of the wrist: Fenton's syndrome

The authors report about chronic Fenton's syndrome. This rare injury of the wrist is characterized by scapho-capitate fracture accompanied by 180° rotation of the head of capitate and associated perilunate dislocation. Two patients suffering from chronic Fenton's syndrome were treated with pyrocarbon capitate resurfacing prosthesis. Patients were evaluated according to the wrist range of motion, Mayo modified wrist and DASH scores. In conclusion, prosthetic surgery may achieve satisfactory results for this rare and diagnostically challenging syndrome.

Arthroscopic findings of Kienbock's disease

PurposeKienböck's disease affects the lunate bone, and osteoarthritis changes progress as the disease advances; however, relatively few studies have reported the arthroscopic findings of Kienböck's disease, and these reports have been in small populations. The purpose of this study was to review arthroscopic findings in a larger population than studied in previous reports. MethodsWe retrospectively reviewed 57 patients who underwent radial osteotomy for Kienböck's disease after arthroscopy of both the radiocarpal and midcarpal joints. All arthroscopic findings were classified as follows in terms of the location of osteoarthritic changes: lunate fossa of the radius, proximal/distal surface of the lunate bone, and capitate head. Radiological stages were classified according to the modified Lichtman's classification system. ResultsAll but two patients had cartilage lesions in the proximal lunate cartilage. Older patients had significantly more cartilage lesions, but radiological stage showed no correlation with the number of cartilage lesions. ConclusionsThis study demonstrated that the proximal lunate bone was affected in most cases of Kienböck's disease and that older patients had more cartilage lesions.

Inflorescence structure in Rhynchospora Vahl (Cyperaceae)

We investigated the inflorescence structure of Rhynchospora following the methodology and terminology of Troll's school, with the objective of providing a characterization of the inflorescence suitable to evaluate the processes responsible for the diversity observed. Homogenization of inflorescence structures may occur fully or partially. In the first case, all branches of the inflorescence are homogeneous, while in the later, distal and proximal parts of the inflorescence bear homogeneous branches, but in the middle portions of the inflorescence non-homogeneous branches exist. Other characters leading to different forms of inflorescences are branching degree, internode elongation along the main axis of the synflorescence, degree of epipodium elongation of distal paraclades, development of bract and prophyll, and development of prophyllar paraclades. We identified three main types of inflorescences: (1) partially homogeneous paniculodia, (2) partially homogeneous capitate heads, and (3) a fully homogeneous capitate head. Within the first type, four subtypes were also recognized. Finally, we discuss how these processes can operate to produce the variation of the inflorescence shape.

Avascular Necrosis of the Capitate

Although a large portion of the capitate is supplied by a single nutrient vessel, avascular necrosis of the capitatum is a rare condition. Its etiology is not clear, but a number of factors are linked to its pathogenesis including: repetitive trauma, dorsal instability of the carpus, Gaucher disease, systemic lupus erythematosus, gout, and steroid use. A 24-year-old woman presented with right wrist pain of 12 months duration. She reported no major trauma and reported that her pain had begun during the third month of her pregnancy. She had a history of hyperemesis gravidarum treated with 2 to 4 mg/daily of prednisone during her pregnancy for 6 weeks. She had 70° extension and 45° flexion of her wrist. Radiographs showed a hypodense area at the capitate head and midcarpal joint arthritis. Magnetic resonance imaging demonstrated avascular necrosis of the capitate and midcarpal collapse at the lunocapitate joint. Lunocapitate fusion with a partial scaphoidectomy was performed. At final follow-up 28 months postoperatively, she had 60° of volar flexion, and 50° of dorsiflexion. She was pain free in the majority of her activities of daily living. A small dose of steroid use during pregnancy, even in a short period of time, is a potential risk for avascular necrosis of the capitate and patients with a gradual onset of wrist pain during pregnancy may need to be investigated further if symptoms are not resolved with basic nonoperative measures within a reasonable time frame.

Careful Climbing in the Miocene: The Forelimbs of Ardipithecus ramidus and Humans Are Primitive

The Ardipithecus ramidus hand and wrist exhibit none of the derived mechanisms that restrict motion in extant great apes and are reminiscent of those of Miocene apes, such as Proconsul. The capitate head is more palmar than in all other known hominoids, permitting extreme midcarpal dorsiflexion. Ar. ramidus and all later hominids lack the carpometacarpal articular and ligamentous specializations of extant apes. Manual proportions are unlike those of any extant ape. Metacarpals 2 through 5 are relatively short, lacking any morphological traits associable with knuckle-walking. Humeral and ulnar characters are primitive and like those of later hominids. The Ar. ramidus forelimb complex implies palmigrady during bridging and careful climbing and exhibits none of the adaptations to vertical climbing, forelimb suspension, and knuckle-walking that are seen in extant African apes.

Scaphoid nonunion and distal fragment resection: analysis with three-dimensional rigid body spring model

Background.Distal fragment resection is one of the salvage procedures for scaphoid nonunion with osteoarthritis. Despite being reported as a simple procedure with favorable midterm outcomes, further arthritic changes remain a concern in the long term. Scaphoid waist fracture is classified into volar or dorsal types according to the displacement pattern, but the indications for distal fragment resection have never been discussed for these fracture types. Method.We reconstructed a normal wrist model from computed tomography images and performed theoretical analysis utilizing a three-dimensional rigid body spring model. Two types of scaphoid fracture nonunion followed by distal fragment resection were simulated. Results.With volar-type nonunion, the force transmission ratio of the radiolunate joint increased, and the pressure concentration was observed in the dorsal part of the scaphoid fossa and volar part of the lunate fossa of the radius; no deterioration was seen in the midcarpal joint. In the distal fragment resection simulation for volar-type nonunion, pressure concentrations of the radiocarpal joint resolved. With dorsaltype nonunion, force transmission ratio in the radiocarpal joint resembled that of the normal joint model. Pressure concentrations were observed in the dorsoulnar part of the scaphoid fossa and radial styloid. The pressure concentration in the dorsoulnar part of the scaphoid fossa disappeared in the resection model, whereas the concentration in the radial styloid remained. In the midcarpal joint, pressure was concentrated around the capitate head in the nonunion model and became aggravated in the resection model. Conclusions.With volar-type scaphoid nonunion, distal fragment resection seems to represent a reasonable treatment option. With dorsal-type nonunion, however, pressure concentration around the capitate head was aggravated with the simulated distal fragment resection, indicating a potential risk of worsening any preexisting lunocapitate arthritis.

Proximal Row Carpectomy: Role of a Radiocarpal Interposition Lateral Meniscal Allograft

The purpose of this study was to determine whether use of a lateral meniscal interposition allograft combined with proximal row carpectomy would reduce the peak joint contact pressures and increase the contact area when compared with proximal row carpectomy alone. Six cadaver wrists were cyclically moved through flexion-extension and radioulnar deviation ranges of motion. Joint contact pressure was measured with the carpus intact, after proximal row carpectomy, and after insertion of a lateral meniscal allograft. Contact pressure data were also collected with the wrist in 5 static positions. Proximal row carpectomy caused statistically greater peak pressures and smaller contact areas when compared with the intact wrist. Insertion of the allograft statistically restored the pressures and areas to that observed in the intact wrist. These results support the clinical trial of a lateral meniscal interposition allograft in patients with contraindications for proximal row carpectomy, such as pre-existing arthritis in the capitate head or lunate facet of the radius.

Proximal Row Carpectomy Versus Four-Corner Arthrodesis as a Treatment for SLAC (Scapholunate Advanced Collapse) Wrist

Four-corner arthrodesis and proximal row carpectomy are motion-preserving salvage solutions for the scapholunate advanced collapse wrist. We compared both procedures in a non-randomised, retrospective study of 30 cases with a mean follow-up of 3(1/2) years. Pain relief and functional gain were equal in both treatment groups. However, the complication rate was higher in the four-corner arthrodesis group, partly because of the need for internal fixation. The higher incidence of carpal tunnel syndrome following four-corner arthrodesis is intriguing. We also found significant differences in the duration of hospital stay and of postoperative sick leave in favour of proximal row carpectomy. If the cartilage on the capitate head is well preserved (Stages I-II), we prefer proximal row carpectomy because of the socio-economic benefits, the lower complication rate and the ease of the procedure. Degenerative changes following proximal row carpectomy may be a concern in young manual labourers, but have not been observed.

Locomotor hand postures and the functional anatomy of the hominid wrist

The African apes have stable wrists with limited mobility—probably for energetic efficiency while using the hand as a rigid, propulsive lever during knuckle‐walking (KW). In contrast, the Asian apes have mobile wrists to facilitate a variety of arboreal hand postures. Testing the KW ancestor hypothesis for hominins requires understanding mechanisms of wrist stability in African apes and subsequent identification of related anatomy in the fossil record.A CT‐based method to track 3D carpal kinematics was used to study midcarpal joint mechanics in Pan troglodytes and Pongo pygmaeus. Midcarpal extension in Pan is distinguished by scaphoid supination on the capitate head, which rapidly close‐packs the midcarpus. Coupled with scaphoid‐centrale fusion and a centrale‐capitate ligament, this limits extension and ensures that the scaphoid and capitate act as a rigid unit. Scaphoid‐centrale fusion and a Pan‐like scaphocapitate joint in early hominins suggest a similar midcarpal mechanism, which may indicate a KW ancestor; alternatively, the mechanism may be a more generalized quadrupedal adaptation. Studying carpal kinematics in quadrupedal monkeys will test this alternative hypothesis. Modifications to the scaphocapitate joint and loss of the centrale‐capitate ligament in later hominins probably resulted in the more mobile modern human wrist.Funding: NSF BCS‐622515, Wenner‐Gren Foundation, Sigma Xi, ASU

Proximal Row Carpectomy With Capitate Resection and Capsular Interposition for Treatment of Scapholunate Advanced Collapse

Proximal row carpectomy with capitate head resection and dorsal capsular interposition was performed in 8 patients with stage II and III scapholunate advanced collapse (SLAC). Mean patient age was 58.5 years (range, 50-79 years). One year postoperatively, range of motion and grip strength were not significantly changed from preoperative values. Mean postoperative Disabilities of the Arm, Shoulder, and Hand questionnaire score was 27. Pain improved from 8.8 preoperatively to 4.3 postoperatively on a scale of 0-10. Pain levels were highly inversely correlated with final range of motion (r=-0.94, P=.0004). Proximal row carpectomy with capitate leveling and capsular interposition for stage II and III SLAC wrist provides reasonable pain relief in 75% of patients. Patients should be counseled that 25% of cases may demonstrate progression of radiocapitate degeneration, necessitating further intervention.

Osteochondral Resurfacing (OCRPRC) for Capitate Chondrosis in Proximal Row Carpectomy

Proximal row carpectomy (PRC) can be an effective treatment option for arthritis of the wrist, but the operation is contraindicated when there is substantial arthritis of the capitate head. We describe a new technique that involves resurfacing of the capitate when there is chondrosis by using osteochondral grafts harvested from the resected carpal bones. The purpose of this study was to assess the outcomes of patients who had osteochondral resurfacing in the setting of PRC (OCRPRC) for capitate chondrosis and to determine how they compare with published results of conventional PRC. Patients having PRC who had grade II to IV (Modified Outerbridge Scale) capitate chondrosis underwent osteochondral resurfacing of the capitate. Preoperative and postoperative pain level, employment status, range of motion (ROM), grip strength, and Mayo wrist scores were assessed, and Student's t-test was used. Postoperative Disability of the Arm, Shoulder and Hand (DASH) scores were also calculated. Eight patients with an average age of 53 years were followed up for 18 months. Preoperatively, 7 patients described their pain as moderate to severe; postoperatively, 7 patients described their pain as mild to no pain. Preoperative arc of motion was 84 degrees (74% of the contralateral side); postoperative arc of motion was 75 degrees (66% of the contralateral side). Preoperative grip strength was 29 kg, or 62% of the contralateral side; postoperative grip strength was 34 kg, or 71% of the contralateral side. Preoperative Mayo wrist score was 51 ("poor"); postoperative Mayo wrist score was 68 ("fair"). Average postoperative DASH score was 19.5. Follow-up radiographs showed that 75% of patients had mild to no degeneration. Magnetic resonance imaging at 21 months postoperatively showed graft incorporation. No complications were encountered. Our results with osteochondral resurfacing compare favorably with the published results of conventional PRC in terms of pain relief, employment status, ROM, and grip strength.

Carpal Kinematics After Proximal Row Carpectomy

Proximal row carpectomy (PRC) is a clinically useful motion-sparing procedure for the treatment of certain degenerative conditions of the wrist. Clinical outcome studies after PRC have shown that wrist flexion-extension averages approximately 60% of that of the contralateral wrist. The purpose of this study was to determine how the kinematics of the wrist are altered after PRC. Eight fresh-frozen cadaver forearms were scanned with computed tomography before and after PRC. Forearms were scanned in 5 different wrist positions (neutral, extension, flexion, radial deviations, and ulnar deviation). Wrists were positioned dynamically and then held statically in a custom fixture through forces applied to the 4 wrist flexor/extensor tendon groups. Three-dimensional computer models of the radius, lunate, and capitate were generated from the computed tomographic images, and the kinematics of the capitate and lunate were calculated relative to the neutral position. For the intact wrist, the motion of the capitate was calculated relative to both the lunate (midcarpal motion) and the radius (overall wrist motion) and the motion of the lunate was calculated relative to the radius (radiocarpal motion). After PRC, only the movement of the capitate relative to the radius was calculated, which represents radiocapitate and overall wrist motion. All motions were plotted in 3 dimensions for purposes of qualitative visualization. After PRC, the capitate articulated with the lunate fossa of the radius for all positions in all samples. Overall wrist motion decreased 28%, 30%, 40%, and 12% in flexion, extension, radial deviation, and ulnar deviation, respectively. Motion at the radiocarpal joint after PRC, however, was greater compared with motion at the radiocarpal and midcarpal joints of the intact wrist during flexion and extension. This was not the case in radial deviation because of impingement of the trapezoid on the radial styloid. In radial and ulnar deviation, motion of the capitate head changed from predominantly rotational in the intact wrist (midcarpal joint) to a combination of rotation and translation after PRC (radiocarpal joint). Removal of the proximal carpal row decreased normal wrist flexion and extension. Although ulnar deviation was preserved, radial deviation was limited by impingement of the trapezoid on the radial styloid. Radiocapitate range of motion after PRC was greater than capitolunate range of motion in the intact wrists. Compared with previously published requirements, wrist range of motion observed after PRC was sufficient for activities of daily living.

Proximal row carpectomy and intercarpal arthrodesis for the management of wrist arthritis.

For advanced noninflammatory wrist arthritis, the most common surgical treatments to preserve motion are proximal row carpectomy and scaphoid excision with capitohamate-lunotriquetral arthrodesis. Both procedures have documented successful outcomes. Proximal row carpectomy is simpler but typically is contraindicated when degeneration of the capitate head cartilage exists. Scaphoid excision with capitohamate-lunotriquetral arthrodesis is more complex but may provide greater grip strength and can be successful in the presence of capitate degeneration. Treatment selection should be based on surgeon preference and experience as well as on the patient's understanding of the possible complications and benefits of each procedure.

Resection of the first row of carpal bones: post-traumatic wrist and Kienbock's disease

This study reports the outcomes of 27 proximal row carpectomies for stage II (Watson) scapholunate--(10 Slac) and scaphoid non union--(8 Snac) advanced collapse and stage III (Lichtman) Kienböck's disease (9 cases) followed for an average of respectively 72 and 50 months. Following surgical treatment, more than 80% of patients in both groups were pain free. The total arc of motion averaged 67 degrees (unchanged), for the post-traumatic arthritis, and 59 degrees for Kienböck's, a decrease of 17%. Grip strength averaged a 17% increase in comparison to the opposite size for both groups. Proximal row carpectomy showed a high degree of patient satisfaction and is a motion-preserving and grip-preserving procedure used in stage II post-traumatic arthritis but Lichtman III stage in Kienböck's disease had a comparatively poor result. Proximal row carpectomy simplifies the structure of the radiocarpal joint. When the cartilage on the capitate head and the radial lunate facet are not worn, this procedure provides a good result with respect to pain, range of motion and strength which is stable with time.

Palmar tilt of the distal radius: influence of off-lateral projection initial observations.

To evaluate the effect of slight off-lateral positioning of the wrist on measurements of the palmar tilt of the distal radius on lateral views and to determine how this effect can be corrected quantitatively. Seven cadaveric forearms in neutral and various oblique positions (5 degrees, 10 degrees, 15 degrees, 20 degrees ) of supination and pronation were examined with lateral radiography. The palmar tilt of the distal radius measured on the radiographs was correlated with each position of the wrist and the distance between the position of the palmar cortex of the pisiform bone (P) and a reference point (point 0), which was defined as the midpoint within the interval between palmar cortices of the distal scaphoid pole and of the capitate head (P0 distance). The same measurements were performed on 11 wrists during arthrography. The apparent palmar tilt of the distal radius increased with supination of the forearm. Regression analysis with the P0 distance as independent and palmar tilt as dependent variables resulted in a slope of 0.95 in the seven cadaveric wrists and of 0.92 in the 11 wrist arthrograms. The squares of the correlation coefficients (R(2)) were 0.89 in cadaveric wrists and 0.69 in 11 wrist arthrograms. Differences in the palmar tilt produced by off-lateral projections of the wrist can be estimated from the measured difference of the P0 distance. A 1-mm difference in the P0 distance corresponds to a difference in the palmar tilt of approximately 1 degrees.

Proximal row carpectomy

Excision of the proximal carpal row has proven over the past 60 years to be an effective technique for certain disorders of the wrist, including degenerative sequelae of scapholunate ligament dissociation and scaphoid nonunions, Kienböck disease, Preisser disease, and other fracture-dislocations of the wrist. The durability of this procedure may be due to remodeling of the capitate head to the lunate fossa. Poor results have been noted in patients with rheumatoid arthritis and arthrogrypotic wrist deformities. Preservation of relatively normal cartilage of the capitate head as well as the lunate fossa is critical for success of this procedure. Average outcomes of this procedure include a wrist extension-flexion arc of 75° and grip strength of 60% of the uninvolved wrist. Revision to total wrist arthrodesis is required in 10% of patients. Approximately 90% have pain relief and can return to moderate use activity. Copyright © 2001 by the American Society for Surgery of the Hand

Analysis of helical axes, pivot and envelope in active wrist circumduction

Objective. To study active wrist circumduction and planar moves, in terms of anatomical angles and envelope and of finite helical axes and mean pivot point. Design. We measured the position of the “mean pivot point” and its mean distance to the axes as anatomical angles in an in vivo full range movement. Background. The mean pivot point has been used in in vitro and roentgen stereophotogrammetric studies of wrist kinematics. However, the distribution of “3D centers of rotation” has never been presented in a non-invasive in vivo study. Methods. A light 6 degrees of freedom electrogoniometer was built and employed in vivo to measure circumduction, flexion–extension and radioulnar deviation on both wrists of twenty one volunteers. Results. Results were in general agreement with previously published ranges of wrist planar motion. The circumduction envelope proved to be a relevant representation of active wrist motion. The “mean pivot point” displayed a relative dispersion in localization of this point. Conclusion. The pivot results suggest that the wrist acts as a universal joint but with a non fixed location in the capitate head. The major axis of wrist envelope was not skew. Relevance The envelope and the precise knowledge of the helical axis pivot and its mean distance to the axes could give precious information on wrist functionality and stability after surgical or conservative treatment.

The ultrastructure of the spermatozoon ofParadynomene tuberculata Sakai, 1963 (Crustacea, Brachyura, Dynomenidae): Synapomorphies with dromiid sperm

The dynomenid spermatozoon, exemplified here byParadynomene tuberculata, resembles the spermatozoa of the Dromiidae, Homolidae and lyreidine raninoids and differs markedly from those of other crabs (the heterotreme, thoracotremes, raninines and raninoidines) in the depressed, discoidal form of the acrosome and the capitate form of the perforatorium. Four or five apparent dynomenid—dromiid sperm synapomorphies are recognizable. (1) Dynomenids (P. tuberculata) and dromiids differ from homolids and lyreidines in the greater depression of the acrosome (ratio of length to width=0.3); (2) the capitate head of the perforatorium is bilaterally prolonged inP. tuberculata as in dromiids though symmetrical in homolids; (3) dynomenid and dromiid sperm lack the—albeit variably developed—posterior median process of the nucleus seen in homolids, anomurans, raninoids and lower heterotremes; (4)P. tuberculata, like dromiids and less distinctly homolids, has an apical protuberance of subopercular material through the opercular perforation, unknown in other crabs, being distinct from the apical button of thoracotreme sperm; (5) a less certain synapomorphy is the anterolateral electron-pale peripheral zone of the acrosome. These synapomorphies endorse a sister-group relationship of dynomenids and dromiids,P. tuberculata sperm differs notably from the sperm of dromiids in the more complex zonation of the acrosome. The perforatorium lacks the radial rays (“spiked wheel”) of homolid sperm and does not show the “amoeboid” form seen in lyreidines. Absence of internal corrugations of the perforatorial chamber is a major difference from all examined raninids. Centrioles are only very tentatively identifiable. Nuclear arms are absent in glutaraldehyde fixed spermatozoa ofP. tuberculata and have not been observed in the dromiidPetalomera lateralis but are present as three small radial vertices in the dromiidDromidiopsis edwardsi and in homolids.P. tuberculata resemblesPetalomera lateralis in the large size of the sperm nucleus relative to the acrosome compared withD. edwardsi and homolids.