Scapholunate ligament reconstruction using a periosteal flap of the iliac crest: a biomechanical study

INTRODUCTION

Advances continue to improve direct reconstruction of the dorsal scapholunate (SL) ligament, which is the strongest part of the entire SL ligament and is known as the turning point between the scaphoid and lunate. This study was designed to compare the biomechanical properties of the dorsal SL ligament with those of a periosteal flap of the iliac crest, which is a new graft candidate for dorsal SL reconstruction.

MATERIALS AND METHODS

A bone-ligament-bone complex was harvested for biomechanical testing from the iliac crest and the dorsal SL complex. Ten specimens could be prepared in each group. After potting the bone blocks in methylmethacrylate for stable fixation, the specimens were tested, using a servohydraulic testing system, at a rate of 10 mm/min.

RESULTS

Failure displacement, failure force, failure stress, energy to failure, and stiffness were assessed for both groups. Eight specimens in each group were tested successfully. In the ligament group, six specimens failed at the ligament level, whereas two failed at the insertion of the scaphoid. In the periosteum group, all eight specimens failed at the ligament level. The failure force of the dorsal SL ligament averaged 171.8 N, failure stress was 10.3 N/mm2, and failure displacement amounted to 2.9 mm. Energy to failure was 269.1 N-mm, and stiffness averaged 77.2 N/mm. Failure force of the periosteal flap amounted to 144.3 N, failure stress was 9.9 N/mm2, failure displacement was 3.0 mm, and energy to failure was 217.9 N-mm. Stiffness of the periosteal flap measured 60.5 N/mm. Comparison of the dorsal SL ligament and the periosteal flap of the iliac crest revealed no significant biomechanical differences.

CONCLUSION

Therefore, the biomechanical properties of the periosteal flap recommend its use for reconstruction of the dorsal SL ligament.

Dorsal scapholunate ligament reconstruction using a periosteal flap of the iliac crest

INTRODUCTION

To report a new technique for scapholunate ligament reconstruction, using a periosteal flap of the iliac crest.

MATERIALS AND METHODS

In 12 patients with static SL instability, a periosteal flap was harvested from the anterior portion of the iliac crest. Following repositioning of the carpals, the flap was fixed to the scaphoid and lunate between an incompletely osteotomised scale at the dorsal horn of the scaphoid and lunate. Pin fixation of the scapholunate (SL) and CL interval secured postoperative reduction for 8 weeks. A forearm plaster cast was worn for 12 weeks.

RESULTS

Eleven patients, all male, were available for follow-up at an average of 29 months. The interval between trauma and surgery averaged 15 months. The preoperative SL angle measured 77 deg, CL angle was -10 deg, and SL gap amounted to 5.2 mm. At follow-up, SL angle was 59 deg, CL angle measured -2 deg, and SL gap was 2.1 mm. SL gap, SL angle, and CL angle improved significantly from preoperative to follow-up values. According to the clinical grading system of Green and O'Brian, 6 patients scored in the excellent and good category and 5 in the fair category. Using the radiologic grading system of Gickel and Millender, 9 patients scored as excellent and good, whereas the 2 poor results were due to failure of the technique.

CONCLUSION

The technique enables reduction of the SL angle and SL gap in patients with static reducible scapholunate instability. The initial results are quite encouraging.

Anatomical basis for functional treatment of dorsolateral dislocation of the proximal interphalangeal joint

Dorsolateral dislocation of the proximal interphalangeal (PIP) joint is a common injury to the hand. Closed reduction of the dislocation anatomically realigns the avulsed ligaments; thus patients may be managed non-operatively. Standard treatment involves placement of a dorsal splint to prevent hyperextension and lateral stresses. This allows early active motion of the PIP joint while preventing a flexion contracture. In this fresh cadaver study, the PIP joint in 24 fingers was dorsolaterally dislocated. Four digits had to be excluded from the investigation due to a fracture dislocation with a bony fragment of >40% of the articular surface of the middle phalanx. After closed reduction, seven digits were further studied using the cryosection technique described by Kathrein et al. (1996, Clin. Anat. 9:227-231) to demonstrate the position of the avulsed palmar plate. In another 13 joints, the torn ligaments were examined by gross dissection. In 10 degrees of finger flexion, the avulsed palmar plate lay at its previous attachment to the base of the middle phalanx. The collateral ligament, ruptured at its attachment to the side of the head of the proximal phalanx, returned to its original position and was not interposed in the joint. The split between the collateral ligament and the accessory collateral ligament was also closed. Our data suggest that the ligamentous structures of the PIP joint, namely the palmar plate and collateral ligaments, typically return to their anatomic positions upon simple closed reduction of dorsolateral dislocations in fresh cadavers.

Randomized phase III study of high-dose fluorouracil given as a weekly 24-hour infusion with or without leucovorin versus bolus fluorouracil plus leucovorin in advanced colorectal cancer: European organization of Research and Treatment of Cancer Gastrointestinal Group Study 40952

PURPOSE

This trial was conducted to determine whether high-dose fluorouracil (FU) given as a weekly 24-hour infusion is more active than bolus FU + leucovorin (LV), and whether high-dose infusional FU can be modulated by LV.

PATIENTS AND METHODS

A total of 497 patients with previously untreated metastatic colorectal cancer were randomly assigned to receive bolus FU 425 mg/m2 intravenously + LV 20 mg/m2 on days 1 to 5 and repeated on day 28 (FU + LV), or FU 2600 mg/m2 as a 24-hour infusion alone (FU24h) or in combination with 500 mg/m2 LV (FU24h + LV)-all given weekly x6 followed by a 2-week rest period. Survival was the major study end point.

RESULTS

With a median follow-up of more than 3 years, survival did not differ among the treatment groups (median FU + LV, 11.1 months [95% CI, 10.2 to 15.0 months]; FU24h, 13.0 months [95% CI, 10.4 to 15.4 months]; FU24h + LV, 13.7 months [95% CI, 12.0 to 16.4 months]; P =.724). Progression-free survival (PFS) was significantly longer for FU24h + LV (median FU + LV, 4.0 months [95% CI, 3.4 to 4.9]; FU24h, 4.1 months [95% CI, 3.4 to 5.0]; FU24h + LV 5.6 months [95% CI, 4.4 to 6.7]; P =.029). The response rates in the subgroup of patients with measurable disease were 12%, 10%, and 17% for FU + LV, FU24h, and FU24h + LV, respectively (not significant). Occurrence of grade 3 and 4 diarrhea was higher in the FU24h + LV arm (22%) compared with the FU24h (6%) or FU + LV (9%) arms; however, stomatitis (11% in FU + LV v 3% in FU24h v 5% in FU24h + LV arms) and hematologic toxicity were higher in the bolus FU + LV arm. Global quality of life did not differ within the three arms.

CONCLUSION

Neither FU24h + LV nor FU24h prolong survival, relative to bolus FU + LV. Leucovorin increases PFS if added to FU24h, but increases toxicity.

[Long-term results after a modified Sauvé-Kapandji procedure. Report on 105 post-traumatic cases]

A modified Sauvé-Kapandji procedure was performed on 105 patients for a painfully limited range of motion and arthritis of the distal radioulnar joint following distal fracture of the radius ( n=81), the radius and ulna in the distal one-third ( n=18) and of the forearm shaft ( n=6). After an average of 8 years all patients were followed up clinically (motion, strength, pain) and radiographically (union of the arthrodesis, carpal translation, radioulnar distance). Rotation of the forearm had been improved by 53%. The amount of strength lay by 70% in comparison to the contralateral side. In 97% of the patients pain could be reduced. In all cases the arthrodesis had fused completely. An ulnar drift of the carpus was observed in 5% of the patients, and 74% of the patients showed radiological signs of approximation of the proximal ulnar stump to the radius. This reduction of the radioulnar distance amounted to less than 3 mm in 65% of the patients and lay between 3 and 5 mm in 29% of the patients. In none of the cases was direct contact between the ulna and the radius encountered.

Closed reduction transarticular Kirschner wire fixation versus open reduction internal fixation in the treatment of Bennett's fracture dislocation

Thirty two patients with fracture dislocations of the base of the thumb metacarpal with a single large fracture fragment (Bennett's fracture) were either treated by open reduction and internal fixation or closed reduction and percutaneous transarticular Kirschner wiring. All were assessed at a mean follow up of 7 (range 3-18) years. Patients with an articular step off more than 1mm were excluded. The type of treatment did not influence the clinical outcome or the prevalence of radiological post-traumatic arthritis. The percutaneous group had a significantly higher incidence of adduction deformity of the first metacarpal. This was attributed to Kirschner wire placement near the fracture line or in the compression zone of the fracture, resulting in loss of reduction. This however did not result in an inferior outcome.

The thyroid hormone receptor and the insulator protein CTCF: two different factors with overlapping functions

Thyroid hormones and thyroid hormone receptors (TRs) confer a fundamental regulation of critical genes involved in metabolism, differentiation, and development. A similar role is attributed to the highly conserved zinc-finger factor CTCF. Furthermore, a potential role in tumour suppression has been attributed to CTCF. In addition to promoter regulation, CTCF has also been shown to be involved in chromatin insulation or enhancer blocking. In several cases, binding sites for TR and for CTCF have been found next to each other. Functionally, these sites mediate synergistic repression or induction dependent on the type of binding site and on the presence or absence of thyroid hormone. Here we discuss functional similarities between TR and CTCF and their roles within these composite elements.

Stage 3 Kienböck's disease: reconstruction of the fractured lunate using a free vascularized iliac bone graft and external fixation

Eighteen patients with stage 3 Kienböck's disease were treated by débridement of the necrotic core of the lunate and implantation of a free vascularized corticocancellous iliac bone. The wrist was stabilized with an external fixator during healing. The efficiency of the procedure for restoring the structure of the fractured lunate, preventing carpal collapse and improving the clinical outcome was assessed at a mean follow-up of 5 years. The graft became incorporated in the lunate in 16 of the 18 patients and no fracture of the reconstructed lunate or carpal collapse occurred in these cases. The graft did not integrate and was resorbed in the other two patients.

[Distal radius fractures and concomitant lesions. Experimental studies concerning the pathomechanism]

Since Colles (1814) first described a distal radius fracture and the publication by Dupuytren (1834), the frequency of and problems surrounding these fractures were increasingly recognised. Not only the treatment but also the formation and type of fracture were repeatedly analysed. The various theories concerning the pathomechanism led to names such as: "tear fracture", "bend fracture", "thrust fracture", "compression fracture", "snap fracture" and others. In our experimental studies we attempted to simulate the pathomechanism of distal radius fractures and present them pictorially. With the help of a materials testing machine, 63 prepared cadaver arms were hyperextended in the wrist joint until a radius fracture occurred. The concomitant lesions were registered radiologically and by dissection. Moreover, additional cadaver arms were deep-frozen and examined by means of computer tomography and cryosection according to Kathrein. Through experimental hyperextension it was possible to generate dorsal, central, and palmar types of fractures. We produced 42 dorsal, 14 central and 7 palmar fractures. Fundamentally, it seems that the fracture depends on the extent in which the carpal bones of the proximal row are pressed against the dorsal, central or palmar part of the articular surface of the distal radius. The subsequent dissection showed in 40 cases (63 %) mostly multiple concomitant lesions and in 23 cases (37 %) none of these. The reason for concomitant lesions may be the proportion of bone stability to the strength of ligaments. Most frequently (27 cases, i.e. 43 %), we found a destabilisation of the articular disk with or without a bony avulsion fragment (fracture of the ulnar styloid). We also commonly found ruptures of the interosseous ligaments between scaphoid and lunate (20 cases, i.e. 32 %) and lunate and triquetrum (11 cases, i.e. 18 %). It is difficult to apply knowledge gained from experimental studies on preserved cadaver arms clinically. There are of course no physiological reflexes and the slow fracture process must be taken into consideration. This holds true not only for concomitant lesions but also for the type of fracture. On the other hand, in these experimental studies it was possible to generate many realistic types of fractures with their concomitant lesions.

Chemistry of porphyrin-appended cellulose strands with a helical structure: spectroscopy, electrochemistry, and in situ circular dichroism spectroelectrochemistry

Around 100 porphyrin units have been selectively linked at C(6)-O to a cellulose (Avicel). The properties of the metal-free and zincated porphyrin-celluloses 2 and Zn-2 have been determined by optical and electrochemical methods. Circular dichroism indicates a helical arrangement of the porphyrin units and reveals intra-chain coupling reminiscent, in the broadest sense, of strands of nucleic acids. Cyclic voltammetry and spectroelectrochemistry have been used to characterize the radical ions and dianions. The electrochromism of the oxidation of cellulose 2 to porphyrin radical cations of 2 has been employed for both molecular switching and the transduction of an electrochemical input into chiroptical signal expression.

Addition of a phosphinidene complex to C=N bonds: P-ylides, azaphosphiridines, and 1,3-dipolar cycloadditions

The terminal phosphinidene complex PhPW(CO)5 adds to the imine bond of PhHC=N-Ph to give 3-membered ring azaphosphiridines, which undergo ring-expansion with an additional imine to yield a set of four isomeric five-membered ring diazaphospholanes. Treatment with the diimines PhHC=N-(CH2)n-N=CHPh (n=2,3,4) results instead-in all three cases-in only a single isomer of the (CH2)n bridged diazaphospholane. For n=2 or 3, this aminal group is easily hydrolyzed to afford new 6- and 7-membered ring heterocycles. No intermediate azaphosphiridine complex is observed during the addition reaction to the diimines. B3LYP/6-31G* calculations on an unsubstituted, uncomplexed system suggest that the initially formed P,N-ylide of the H2C=N-(CH)2-N=CH2 diimine both kinetically and thermodynamically favors an intramolecular 1,3-dipolar cycloaddition over an imine insertion into the CPN ring of an intermediate azaphosphiridine. Single-crystal X-ray structures for the (CH2)2-bridged azaphospholane complex and the HCl adduct of the 7-membered hydrolysis product are presented.

Reaction of a complexed phosphinidene with 2,4,6-tri-tert-butyl-1,3,5-triphosphabenzene

The terminal phosphinidene complex PhPW(CO)5 reacts with 2,4,6-tri-tert-butyl-1,3,5-triphosphabenzene to give two unexpected multicyclic organophosphorus compounds. One of them results from an initial 1,2-addition, followed by an intramolecular rearrangement. B3LYP/6-31G* calculations on simplified parent systems suggest that the reaction follows a unique concerted reaction pathway. The second, and major, product is a tetraphosphaquadricyclane derivative, which presumably results from an intramolecular [2+2] cycloaddition of an intermediate tetraphosphanorbornadiene complex. Single-crystal X-ray structures are presented for both products.