Menisci and synovial folds of the metacarpophalangeal joint of the thumb

The inner surface of 25 thumb metacarpophalangeal joints were investigated and the arrangement and structure of different folds protruding into the joint cavity at the level of the joint cleft studied. At the ulnar and radial sides, compact wedgeshaped folds are found consisting of collagenous fibres, which connect with the fibrous layer of the joint capsule. The circularly arranged fibrous tissue is covered by a thin layer of cartilaginous cells. From a structural and functional point of view they are comparable to the menisci of the knee joint. In contrast, a different kind of tissue is found at the palmar and dorsal circumference of the joint cleft: typical synovial folds, consisting of loose connective tissue and small fat lobules. These are suggested not to fulfill a particular mechanical function but to act as a malleable spacer which is able to conform to the requirements of joint mobility.     

Open complex metacarpophalangeal joint dislocation. Two cases: index finger and long finger

Two patients with open complex dislocation of a metacarpophalangeal joint were treated by cleansing of the wound, open reduction, primary wound closure, and early motion. One dislocation occurred in the index finger, the other in the long finger which is only the second such case to be described. Antibiotics were given before and continued for 5 days after operation. There were no infections, and both patients regained an excellent range of motion without pain.     

Isolated traumatic dorsal dislocation of the distal radio-ulnar joint. Report of seven cases

The authors report seven cases of isolated dorsal dislocations of the distal radio-ulnar joint. Four were recent dislocations and three were old, chronic dislocations. Acute dislocations were treated surgically. An anatomic study on human cadavers enabled us to define the injuries responsible for radio-ulnar dislocations. An electromyographic study of the extensor carpi ulnaris confirmed its role as a dynamic stabilizer of the ulnar head. Two of the three old dislocations were revised after an attempt at ligamentous reconstruction. These patients benefitted from a resection of the ulnar head. The third patient one underwent a Sauve-Kapandji procedure. Cadaver studies underline the fact that ligamentous reconstruction procedures are actually tenodeses.     

Bioabsorbable rods and pins for fixation of metacarpophalangeal arthrodesis of the thumb

We report results on the use of bioabsorbable pins and intramedullary rods made of high-molecular-weight polylactic acid in both experimental and clinical conditions. In the experimental study, bioabsorbable rods were implanted in rabbit femora. Histologic assessment on nondecalcified bone showed that resorption of the material began at 4 months after implantation and gradually fragmented over a period of 3 years. In 12 patients 13 metacarpophalangeal joints of the thumb were arthrodesed by using one bioabsorbable intramedullary rod with one or two oblique pins. All joints fused within 6 to 8 weeks. During that period there was no sign of inflammation, and there were no nonunions. Postoperative magnetic resonance imaging assessment was done in all rabbits and eight patients. This modality is a useful tool in postoperative evaluation of the position and shape of the rod but is not sufficiently sensitive to assess the presence of local inflammation and the rate of resorption of the rods.     

Contact areas in the thumb carpometacarpal joint

The thumb carpometacarpal joint is a common site of osteoarthritis. It has been hypothesized that peaks of localized stress on the dorsoradial or volar-ulnar regions, or both, of the articular surfaces of the trapezium and metacarpal lead to erosion of cartilage and may be responsible for the progression of the disease. The objective of this study was to determine the contact areas in this joint under the functional position of lateral (key) pinch and in the extremes of range of motion of the joint. These contact areas were assessed relative to the observed sites of cartilage thinning. Eight hands from cadavers of women and five from cadavers of men were tested in vitro with the thumb under a 25 N load in the lateral pinch position, and under small muscle loads (0-5 N) with the thumb in flexion, extension, abduction, adduction, and neutral positions. Contact areas of articular surfaces of the thumb carpometacarpal joint were determined for these positions using a stereophotogrammetric technique. The lateral pinch position produced contact areas predominantly on the central, volar, and volar-ulnar regions of the trapezium and the metacarpal. In three specimens, contact areas were distinctly separated between the dorsoradial and volar-ulnar regions, and in one specimen, from a man, contact occurred exclusively on the dorsoradial region of the trapezium. Using stereophotogrammetry, maps of cartilage thickness also were determined for a subset of nine specimens. The volar-ulnar, ulnar, and dorsoradial regions of the trapezium were the most common sites of thin cartilage, and these may be sites of cartilage wear.(ABSTRACT TRUNCATED AT 250 WORDS)     

Interposition arthroplasty of the carpo-metacarpal joint of the thumb

Nine patients with osteoarthrosis of the carpo-metacarpal joint of the thumb were treated surgically with the metacarpo-trapezial silicone rubber prosthesis designed by Kessler. Patients with pantrapezoidal changes were specifically excluded. All patients at follow-up had chronic synovitis and in five the prosthesis was dislocated. In three patients who had revision operations the previously inserted prostheses were found to be badly torn.     

Unilateral medial dislocation of the temporomandibular joint

We present our experience of the rare condition of unilateral medial dislocation of the temporomandibular joint (TMJ) in 11 patients with head trauma who had received a direct lateral blow on the chin. The diagnosis was made by direct coronal CT of the TMJ performed from 6 h to 7 days following the injury. In 6 patients, subcondylar fracture of the ipsilateral mandibular ramus was also demonstrated. A second CT performed 11-16 months following the first one demonstrated pseudoarthrosis of the fractured ramus in these 6 patients. The second CT was identical to the first in the remaining 5 patients with pure dislocation of the condyle. All patients suffered from severe disability of the TMJ. The maximal vertical distance between the upper and lower incisors in patients with uncomplicated dislocation ranged between 8 and 12 mm. In cases with complicated medial condylar dislocation with fracture and pseudoarthrosis of the mandibular ramus, this distance ranged between 16 and 25 mm, probably because of additional movement in the area of the pseudoarthrosis. The maximal vertical distance between the incisors was compared with a control group of 20 normal adults who had values from 40 to 52 mm. Medial unilateral dislocation of the TMJ can appear in two forms: uncomplicated or complicated, with pseudoarthrosis of the ipsilateral mandibular ramus.     

Treatment of interphalangeal hyperflexion and metacarpophalangeal hyperextension of the thumb in combined low median-ulnar nerve palsy

A method of treatment of interphalangeal hyperflexion and metacarpophalangeal hyperextension of the thumb in combined low median-ulnar nerve palsy is described. The flexor pollicis longus tendon is divided longitudinally into 2 slips. One tendon strip is cut distally, extracted from the fibro-osseous canal, passed superficial to the tendon sheath, and attached to its previous insertion. An extensor indicis proprius opposition transfer was simultaneously performed. Eleven patients were monitored for 1 to 4 years after surgery. All results were positive, and there were no recurrences of either Froment's or Jeanne's sign.     

Biomechanical evaluation and clinical correlation of 3 methods of internal fixation of metacarpophalangeal arthrodesis of the thumb

Three methods of internal fixation for MCP arthrodesis of fifteen cadaveric thumbs were used to analyze the biomechanical stability by applying a palmar force, lateral force, and torsion moment. The techniques used included two K-wires 0.045 in parallel (BK), 2 cerclage metallic wires #25 perpendicular to each other (CP), and a 6-holes plate and screws construct from Synthes (PV). The initial rigidity was measured using a Bionix MTS-858. The results after statistical analysis showed: 1) CP was just as rigid as PV for the palmar and lateral tests; 2) CP was, overall, superior to BK in palmar and lateral tests; 3) no difference existed in torsion between the three types of fixation. A comparison was done between the rigidity of the fixation techniques used and the rates of bony nonunion found in the literature. The mean rates of nonunion were reported to be 0-4.0% for the following techniques: CP, tension band wiring (TB), plate and screws, external fixation, compression screw. The rates of nonunion were higher, 7.5-12.5%, for BK, cerclages not perpendicular (CM), bone pegs. According to the results of this biomechanical study and the review of the literature, fixation with BK is the least rigid, and fixation with CP is just as rigid as with PV. The success clinically of CP is yet to be demonstrated. Other studies on the properties of CP for fatigue would be necessary to give a better analysis.     

Palmar fracture dislocation of the proximal interphalangeal joint

Palmar fracture dislocation of the proximal interphalangeal joint is uncommon. Thirteen patients treated for this injury were retrospectively reviewed. There were 9 acute injuries. Seven were treated by closed reduction and percutaneous pin fixation and 2 were treated by open reduction and internal fixation. The 4 chronic injuries (more than 1 month after injury) were treated with open reduction and soft tissue reconstruction. The length of follow-up averaged 55 months. Eight patients were free from pain. Postoperative proximal interphalangeal motion averaged 91 for the acute injuries and 70 degrees for the chronic injuries. Follow-up radiographic findings were notable for an increased height of the middle phalangeal base in 6 patients, articular irregularity in 4, and residual subluxation in 2; however, these changes did not correlate with the clinical results. Complications included loss of reduction in 1 patient, progressive swan neck deformity in 1, and development of an average 25 degrees extension lag of the distal interphalangeal joint in 5.     

High implant fracture incidence with Sutter silicone metacarpophalangeal joint arthroplasty

We performed a retrospective review of Sutter silicone metacarpophalangeal (MP) joint arthroplasties in 34 patients (42 hands, 168 implants) with rheumatoid arthritis. Patients were evaluated at an average of 27 months (minimum follow-up period, 12 months). Twenty percent of the implants were shown to be definitely fractured on final follow-up examination, and 45% followed for more than 3 years were definitely fractured. At the final follow-up examination, the average ulnar drift in intact implants was 11 degrees and in the fractured implants, 23 degrees. However, there was no correlation between implant fracture and patient satisfaction. Eighty percent of patients said they would undergo the procedure again. Because of a significantly higher implant fracture incidence at a relatively shorter follow-up period than that of most studies of silicone MP implants of the Swanson design, we have abandoned the use of the Sutter implant.     

Simultaneous dorsal luxation of metacarpophalangeal joints of the four long fingers. Apropos of a case

PURPOSE OF THE STUDY: The authors describe an unusual case of simultaneous dorsal dislocation of the metacarpophalangeal joints of the index, long, ring, and little fingers. MATERIAL AND METHODS: A 67-year-old man fell on the pavement when walking, striking his outstretched left hand. A diagnosis of multiple fingers dislocation was easily clinically and radiologically established. The wound was cleaned and the dislocations reduced by closed manipulation at the operating room. RESULT: The patient had an uneventful recovery, after a three week period of immobilization with a dorsal extension block splint. DISCUSSION AND CONCLUSIONS: The use of art extension block splint allowed a minimal healing delay for disrupted volar metacarpophalangeal structures, allowing a good fingers range of motion.     

Computer evaluation of second tarsometatarsal joint dislocation

Using computer-assisted techniques, this study analyzes the mean contact area of the articular surface of the second tarsometatarsal joint. The articular contact area decreased proportionate to the displacement in both males and females, but it was consistently greater in males than in females for all simulated displacements. The reduction in the contact area was the highest with dorsolateral displacement compared with the lateral and dorsal displacements. Dorsolateral displacement of the second metatarsal of 3 mm led to 38.6% reduction in the contact area, compared with 33.1% and 20.2% reduction with lateral and dorsal displacements, respectively. This study shows that even minor degrees of displacement not apparent on plain radiographs lead to significant decrease in the contact area of the second tarsometatarsal joint. Careful evaluation of second tarsometatarsal injuries with computed tomography is recommended to detect minor degrees of displacement.     

Atraumatic dislocation of the trapeziometacarpal joint secondary to osteoarthritis

We report a case of atraumatic dislocation of the trapeziometacarpal joint secondary to osteoarthritis. An attritional rupture of the anterior oblique carpometacarpal ligament is thought to have occurred, allowing complete dislocation which has led to a reduction in the patient's pain.