Evaluation of an in situ setting injectable calcium phosphate as a new carrier material for gentamicin in the treatment of chronic osteomyelitis: studies in vitro and in vivo.

A study was performed to investigate the effectiveness of hydroxyapatite cement (HAC) as a new carrier system in the treatment of chronic, posttraumatic osteomyelitis. In the in vitro study, release of gentamicin from standard cylinders of HAC were measured by agar diffusion test. As a representative for mechanical properties, compression strength was measured in order to detect changes when mixing HAC with gentamicin. In the in vivo study, bone infection was induced according to the model of Norden by injection of 1 ml Na-morrhuat and 3 x 10(6)CFU Staphylococcus aureus. After 3 weeks, when chronic stage of infection was obtained, 17 animals were treated by debridement and filling the marrow either with HAC alone or HAC mixed with gentamicin (32 mg/g). Animals of the control groups were left untreated. After 6 weeks, all animals were sacrificed. Hematological, radiological, microbiological and histological examinations were carried out by covered investigation. Best evidence of the efficiency of treatment was observed in histopathological and microbiological findings. In all swabs of the control groups, taken 6 weeks following infection S. aureus were detected which were clonal to the strain used for induction of osteomyelitis. In HAC/gentamicin-treated animals, no growth was detectable after 7 days of culturing in BHI bouillon. In the HAC/gentamicin-treated group, there was no histopathological evidence of infection. In all other groups different stages of chronic osteomyelitis were found. No side effect was observed, neither locally nor systemically by HAC or gentamicin. Therefore, HAC is considered to be a very effective carrier for antibiotics in treatment of chronic, posttraumatic osteomyelitis.

[A new irrigation-suction boring system facilities low-pressure intramedullary boring of isolated swine femurs]. / Ein neues Spül-Saug-Bohrssystem ermöglicht die druckarme Markraumbohrung an isolierten Schweinefemora.

AIM: Intramedullary nailing is the treatment of choice for the stabilization of fractures of long tubular bones. An important disadvantage of this method is the increase in intramedullary pressure and the resulting release of fat into the venous blood system during reaming of the medullary canal. We have developed a new type of rinsing-suction-reamer (SSB) in order to minimize these disadvantages. Trials were initiated to investigate whether it is possible to ream the medullary canal with the SSB without pressure increase in comparison with the standard AO-reamer (AOB). METHODS: Reamed intramedullary nailing was performed in 20 isolated pig femora. The intramedullary pressure was recorded continuously. RESULTS: While stepwise reaming was performed, the pressure only rose above the physiological level in AOB. During insertion of the guide wire and the nail, comparable values were measured for AOB and SSB. CONCLUSION: Our experiments show that reaming of the medullary canal is possible without a pressure increase using the SSB in comparison with AOB.

[Postoperative radial paralysis. Fate or negligence, conservative wait or revision?]. / Postoperative Radialisparese. Schicksalhaft oder fahrlässig, zuwarten oder revidieren?

Radial nerve palsy is a rather frequent complication caused by an accident as well as by surgery of the humerus. As a primary, i.e., accidental lesion, its incidence as stated in the literature is up to 30%, primarily fractures in the distal diaphyseal half. Secondary, i.e., surgically induced, nerve lesions surprisingly are reported with a similar frequency, though recently the incidence only approaches some 3%. Experts continue to argue over the timing for operative revision. Many authors rely on spontaneous recovery of the nerve as maintained by L. Boehler in the early 1960s, but this theory was rendered obsolete by the technical achievements of microsurgery and the patients' economic constraints. Other authors are afraid of accidentally damaging the nerve by revision surgery. The stand we take in this controversy is instant revision surgery both for accidental lesions as well as uncompromisingly for those incurred during surgery when the surgeon had not explored the nerve far enough to preserve it during the operation. Three exemplary cases are reported, one of them submitted for an expert's opinion because of an alleged mistake on the part of the doctor. Forensic responsibility has to match actual indication principles and the specific technique applied.

The use of an in situ curing hydroxyapatite cement as an alternative to bone graft following removal of enchondroma of the hand.

Following curettage of enchondromata of the phalanges we filled the resultant bone cavity with hydroxyapatite cement in eight patients to avoid cancellous bone grafting. This material differs significantly from the ceramic hydroxyapatite commonly used in clinical practice. It is produced by the combination of two calcium phosphates which, in the presence of water, form a paste that cures to a solid implant with a microporous structure. Like ceramic hydroxyapatite, this cement is highly biocompatible and does not provoke a foreign body giant cell reaction, a sustained inflammatory response or a toxic reaction. We performed a prospective study with X-rays and clinical assessment up to 1 year after the operation. There were no complications, and all patients regained full function of the hand.

CT of metal implants: reduction of artifacts using an extended CT scale technique.

PURPOSE: The purpose of this work was to use an extended CT scale technique (ECTS) to reduce artifacts due to metal implants and to optimize CT imaging parameters for metal implants using an experimental model. METHOD: Osteotomies were performed in 20 porcine femur specimens. One hundred cobalt-base screws and 24 steel plates were used for osteosynthesis in these specimens. Artificial lesions were produced in 50 screws, such as osteolysis near the screws (mimicking lysis due to infection, tumor, or loosening), displacement of the screws, as well as fractures of the screws. All specimens were examined using eight different CT protocols: four conventional (CCT) and four spiral (SCT) CT protocols with different milliampere-second values (130 and 480 mAs for CCT, 130 and 300 mAs for SCT), kilovolt potentials (120 and 140 kVp), and slice thicknesses (2 and 5 mm). The images were analyzed by three observers using a standard window (maximum window width 4,000 HU) and ECTS (maximum window width 40,000 HU). Receiver operating characteristic analysis was performed, and image quality was assessed according to a five level scale. RESULTS: Metal artifacts were significantly reduced using ECTS (p < 0.05). The highest diagnostic performance was obtained using ECTS with the thinnest slice thickness. Metal artifacts were more pronounced using SCT. In this experimental model, exposure dose and kilovolt potential had no significant impact on diagnostic performance (p > 0.05). CONCLUSION: ECTS improved imaging of metal implants. In this study, no significant effects of exposure dose and kilovolt potential were noted. Metal artifacts were more prominent using SCT than using CCT.

[Callus distraction of the first metacarpal bone for thumb reconstruction after traumatic amputation]. / Die Kallusdistraktion des ersten Mittelhandknochens zur Daumenrekonstruktion nach traumatischer Amputation.

From 1990 to 1997, callus distraction of the first metacarpal bone was performed on 34 patients with a traumatic amputation of the thumb, if replantation was not possible. After a period of 7 +/- 11 months (range, 1-48), a corticotomy and continuous distraction with an external fixator was carried out. Of the patients, 31 (91%) were reviewed after treatment. The follow-up period range was 41 +/- 32 months. With this method, the average lengthening of the thumb was 78% in comparison to the uninjured side. Complications were rupture of the callus in one case, four patients suffered a superficial wound infection, and seven patients showed pin tract infection without osteitis. At follow-up examination, 20 patients (64.5%) showed excellent, 9 (29%) good and 2 patients (6.5%) unsatisfying results.

[Late sequelae and treatment strategies of distal radio-ulnar dissociation after undetected Essex-Lopresti lesion]. / Spätfolgen und Behandlungsstrategien der distalen Radioulnardissoziation nach unerkannter Essex-Lopresti-Läsion.

The Essex-Lopresti lesion, a combination of radial head fracture and distal radioulnar dislocation, rarely occurs but nevertheless represents a frequently unknown result after forearm fracture. The responsible physician soon has to initiate surgical treatment to prevent his patient from permanent pain of the wrist. Previously unrecognised distal radioulnar dislocation remains to be an unsolved problem. A generally accepted management concept does not exist. Since rupture of the membrana interossea nearly ever occurs, resection of the radial head is followed by radial shifting and seems to be obsolete under these circumstances. An exemplary case is presented and surgical management in this situation is discussed.

A new clamping technique for biomechanical testing of tendons in small animals. aprobst@uni-muenster.de.

When biomechanical properties of tendons are studied, the technique of clamping the tendons in the testing machine presents a methodological challenge, especially when murine tendons are examined. These short tendons tend to rupture at the transition line to the fixation, leading to false interpretations. Therefore a new clamping technique for investigation of healthy murine Achilles tendons (n = 50) was developed, in which the intramuscular tendon fibers were fixed between two paper strips and the calcaneus was wedged into a conical slot in a wooden block and then mounted in the testing machine (n = 20). This technique was compared with the conventional clamping technique that fixes both ends of the tendon by clamps (n = 15) and an earlier described method that used glue or plastic cement for the fixation of the intramuscular tendon fibers and calcaneus in the testing machine (n = 15). When tested by the new clamping technique, 17 tendons ruptured intratendinously at a mean tensile force of 8.4 +/- 1.1 N. Three Achilles tendons (17%) tore at the site of paper fixation and had to be excluded from investigation. Data from 73% of the measurements fixed by gluing had to be excluded because slippage of the proximal tendon fibers and contamination of the tendon with glue occurred. All the conventionally clamped tendons ruptured at the site of fixation at a mean tensile force of 6.1 +/- 2.3 N (p < .05). This was 30% lower than with the new clamping technique. Thus, the newly developed clamping technique enables investigators to obtain more valid biomechanical studies of the murine Achilles tendon.

[The treatment of unstable fractures of the distal radius using a bridging external fixator. Results from a long-term evaluation]. / Die Behandlung instabiler distaler Radiusfrakturen mit einem transarticulären Fixateur externe. Ergebnisse einer Langzeitbeobachtung.

INTRODUCTION: The aim of our study was to evaluate external fixation in the treatment of unstable distal radius fractures in a long-term follow-up. METHODS: Within 8 years 174 patients with severely displaced distal radius fractures were included in a prospective study and treated with an external wrist fixator (Orthofix Srl, Italy). A total of 148 patients were reviewed with an average follow-up time of 28 months. RESULTS: Using the functional outcome score according to Gartland and Werley, we obtained 29.3 % excellent, 42.5 % good, 10.3 % fair and 2.9 % poor results; 14.9 % of the patients were not available for follow-up. Additional procedures were carried out in 54.1 % to obtain dorsal stabilization. The list of complications included two major pin-tract infections requiring surgical intervention, one pin cut out of the second metacarpal bone, one fixator dislocation, and one patient had algodystrophy. The length of the radius and joint congruity did not significantly from the situation when the fixator has been removed at the end of the treatment. CONCLUSION: The results show the importance of anatomical reduction, and especially restoration of radial length, in order to obtain good functional outcome.

[Significance of score systems in open complex trauma of the pelvis]. / Zur Bedeutung von Score-Systemen beim offenen Komplextrauma des Beckens.

A quantitative analysis of the injury severity of 40 patients with open pelvic fractures was performed. Data were analyzed using the Statistical-Analysis-System (SAS Institute Inc., Cary, NC) with regard to patients' age, gender, trauma mechanism, classification and nature of the pelvic injury, associated lesions, and mortality. Trauma-scoring included the Hannover-Polytrauma-Score [11], the Pelvis-Fracture-Scale [2] and the Pelvis-Score [19]. Five patients died. The survivors had a mean Polytrauma-Score of 34.1, the nonsurvivors had a mean Polytrauma-Score of 44.6 (p = 0.7; Mann-Whitney-test). The nonsurvivors required highly significant more units of blood transfusions than the survivors (49.4 vs. 14.1; p = 0.003; Mann-Whitney-test). The loss of blood was related to the severity of the injury according to the Polytrauma-Score. There was no significant difference in the Pelvis-Fracture-Scale of survivors and nonsurvivors. Neither there was a significant correlation between the fracture type and the Polytrauma-Score nor between the fracture type and the mortality. The Pelvis-Score--with the variable "bleeding" defined as "major vessel lesion"--was significantly higher in the nonsurvivors than in the survivors (12.0 vs. 4.9; (p = 0.04; Mann-Whitney-test). In conclusion, in this retrospective study the Polytrauma-Score and the Pelvis-Score proved effective regarding some important aspects of the prognostic estimation of the general injury and the pelvic trauma, respectively. The Hannover-Pelvis-Fracture-Scale allows an exact documentation of the pelvic trauma as it pays proper attention not only to the fracture classification but especially to the soft tissue damage.

[Gangrene of the fingers caused by accidental intra-arterial injection of diazepam]. / Fingergangrän nach akzidenteller intraarterieller Injektion von Diazepam.

HISTORY: A 51-year-old woman was accidentally given an intra-arterial injection of 10 mg diazepam to control an acute claustrophobic anxiety attack. She complained of severe knocking pain in the entire left arm during the injection. On the second day the hand and lower arm were red an swollen and she complained of increasingly feeling cold and having paraesthesias. On the fifth day the radial half of the palm as well as the first to third digits showed livid discoloration. In the further course necrotic areas developed in the palmar aspect of the distal phalanx of the thumb and of the index finger proximal to the middle phalanx. INVESTIGATION: Angiography on the tenth day after the injection revealed very poor perfusion of the radial artery as far as the wrist, occlusion of the superficial palmar arterial arch and occlusions of the digital arteries of the five fingers. TREATMENT AND COURSE: Infusion of 25,000 IU heparin over 24 h brought no improvement. On the 24th day after the diazepam injection the palmar aspect of the distal phalanx of the thumb and the index finger became necrotic, requiring amputation of the latter and, after removal of necrotic tissue, flap-plasty using subcutaneous soft tissue of the extensor surface of the index finger to cover the defect on the thumb. The patient was without symptoms on discharge and the wounds were healing well. CONCLUSION: Every doctor should be aware of the dangers of accidental intra-arterial injection. The slightest suspicion and symptoms require immediate and adequate treatment to save the limb.

Anterior interosseous nerve compression after supracondylar fracture of the humerus: a metaanalysis.

OBJECT: The authors conducted a metaanalysis of reports of anterior interosseous nerve syndrome, a rare nerve compression neuropathy that affects only the motor branch of the median nerve. This syndrome is characterized by paralysis of the flexor pollicis longus, the flexor digitorum profundus to the index finger, and the pronator quadratus, with weakness on flexion of the interphalangeal joint of the thumb and the distal interphalangeal joint of the index finger without sensory loss. METHODS: The authors reviewed reports of 34 cases of anterior interosseous nerve syndrome combined with supracondylar fractures of the humerus in children. They have added a new case identified in a 7-year-old boy in whom a diagnosis was made from the clinical findings and whose treatment and outcome are analyzed. The ages of patients reported in the literature ranged from 4 to 10 years. Ten patients (29%) were treated with closed reduction and application of a cast, whereas 25 patients (71%) were treated with open reduction and fixation of the fracture. CONCLUSIONS: All patients regained full flexion and strength after 4 to 17 weeks. The fractures that were surgically treated showed no entrapment of the anterior interosseous nerve.

[Patient motivation--an essential therapeutic tool]. / Patientenmotivation--unverzichtbare therapeutische Hilfe.

A deciding factor for the future functioning of a hand with a mutilating hand injury is the self-motivation that the patient brings with him to rehabilitation. This is illustrated in the case of a guitar teacher who returned to his career after subtotal and total finger amputation of his left hand (used for gripping chords). With consistent exercise on his instrument he compensated for the functional deficits of his hand and won a law suit against his employer who denied that he had the physical ability to play the classical guitar. It is more clear than ever that an injured person is jointly responsible, through self-motivation in the working process, for more-or-less complete rehabilitation. It is not uncommon in a system of job-sharing in which several members of the health service (surgeons, physiotherapists, social workers, general practitioners) must co-ordinate their work, for the patient--if he does not involve himself--to fall by the wayside. It is shown how inherent and rewarding it can be to support the patient in his desire to return to work. Apart from that, we hope that this example will be an encouragement to those similarly affected.

[Differential anterior interosseous nerve syndrome diagnosis]. / Zur Differentialdiagnose des N.-interosseus-anterior-Syndroms.

The differential diagnosis of the rupture of flexor pollicis longus tendon and profundus tendon to index finger to the interosseus anterior nerve syndrome can be difficult and can lead to misinterpretation of the clinical impression. Two cases are reported to demonstrate this problem. In the first case a spontaneous rupture of flexor pollicis longus was found, when first an interosseus anterior nerve syndrome was suspected. In a second case surgical exploration of flexor pollicis longus tendon and profundus tendon to index finger was done on the assumption of a rupture, that revealed intact tendons. In a second operation neurolysis of the interosseus anterior nerve was carried out with full recovery of flexion of the thumb and index finger.

[Osseous avulsion of the ischio-crural muscle group with concomitant sciatica]. / Die knöcherne Avulsion der ischiokrualen Muskelgruppe mit begleitender Ischialgie.

Avulsion fractures of the ischial tuberosity are rare. They are often caused by a typical "splits"-like accident. In general the patients feel sudden severe pain in the buttock with localized tenderness in the region of the ischial tuberosity, rarely in combination with sciatic nerve irritation. According to the functional anatomy, flexion of the knee and extension of the hip may be impaired. Roentgenograms often reveal no abnormality and show no evidence of fracture. Therefore, inadequate therapy because of missed diagnosis can result in avoidable persistent pain. We report on a 42-year-old man with an avulsion fracture of the ischial tuberosity. The epidemiology, symptoms, including irritation of the sciatic nerve, differential diagnoses, diagnostic procedures and therapy are presented in detail.

[Post-traumatic anterior interosseous nerve syndrome after supracondylar humerus fracture in a child]. / Posttraumatisches Nervus-interosseus-anterior-Syndrom nach supracondylärer Humerusfraktur beim Kind.

The interosseus anterior syndrome is a rare nerve compression syndrome that concerns only the motor branch of the median nerve. It is evidenced by paralysis of the M. flexor pollicis longus and M. flexor digitorum profundus II with weakness of flexion of the terminal joint of the thumb and index finger but without sensory loss. From the surgical point of view this complication has special importance because of pediatric fractures of the distal humerus. In this paper we discuss the differential diagnosis, therapy and prognosis of this nerve injury by presenting an illustrative case of a 7-year-old boy suffering a supracondylar fracture of the humerus with a post-traumatic anterior interosseus nerve syndrome.