Jahoda D

Topographic variations of the relationship of the sciatic nerve and the piriformis muscle and its relevance to palsy after total hip arthroplasty

AbstractThe aim of this paper was to study the anatomical relationship between the piriformis muscle and the sciatic nerve with regard to the possibility of neurological deficit after THA. The incidence of anatomical variation of both structures is 15–30% in the literature. The authors studied 91 cadavers and found an atypical relationship in 19 cases (20.9%). In this study individual variations were found with the following frequency: The sciatic nerve exits below the piriformis muscle in 79.1% of the cases.The sciatic nerve separates into two divisions above the piriformis, one branch passing through the muscle, the other below it (14.3%).An unsplit nerve passes through the piriformis muscle in 2.2%.The nerve separates into two divisions above the piriformis, one branch exiting above the muscle and passing along its dorsal aspect, the second exiting distally below the muscle in 4.4%. The most common reasons for sciatic nerve injury in surgery of the hip joint are direct injuries, ischemia of the nerve tissue, compression or excessive distraction of the nerve, compression by bone cement, thermal damage during cement polymerization, injury during THA dislocation, compression by hematoma, bone prominence or an implanted acetabular component. According to the presented anatomical study, overstretching of the nerve itself or its branches in the area of the pelvitrochanteric muscles after their release from their origin can be another mechanism. Such overstretching can appear in the presence of some of the aforementioned anatomical variants.

Total elbow replacement with the Souter-Strathclyde prosthesis in rheumatoid arthritis: LONG-TERM FOLLOW-UP

We assessed the long-term results of 58 Souter-Strathclyde total elbow replacements in 49 patients with rheumatoid arthritis. The mean length of follow-up was 9.5 years (0.7 to 16.7). The mean pre-operative Mayo Elbow Performance Score was 30 (15 to 80) and at final follow-up was 82 (60 to 95). A total of 13 elbows (22.4%) were revised, ten (17.2%) for aseptic loosening, one (1.7%) for instability, one (1.7%) for secondary loosening after fracture, and one elbow (1.7%) was removed because of deep infection. The Kaplan-Meier survival rate was 70% and 53% at ten and 16 years, respectively. Failure of the ulnar component was found to be the main problem in relation to the loosening. Anterior transposition of the ulnar nerve had no influence on ulnar nerve paresthaesiae in these patients.

Isolated talonavicular arthrodesis in patients with rheumatoid arthritis of the foot and tibialis posterior tendon dysfunction

BackgroundThe foot is often affected in patients with rheumatoid arthritis. Subtalar joints are involved more frequently than ankle joints. Deformities of subtalar joints often lead to painful flatfoot and valgus deformity of the heel. Major contributors to the early development of foot deformities include talonavicular joint destruction and tibialis posterior tendon dysfunction, mainly due to its rupture.MethodsBetween 2002 and 2005 we performed isolated talonavicular arthrodesis in 26 patients; twenty women and six men. Tibialis posterior tendon dysfunction was diagnosed preoperatively by physical examination and by MRI. Talonavicular fusion was achieved via screws in eight patients, memory staples in twelve patients and a combination of screws and memory staples in six cases. The average duration of immobilization after the surgery was four weeks, followed by rehabilitation. Full weight bearing was allowed two to three months after surgery.ResultsThe mean age of the group at the time of the surgery was 43.6 years. MRI examination revealed a torn tendon in nine cases with no significant destruction of the talonavicular joint seen on X-rays. Mean of postoperative followup was 4.5 years (3 to 7 years). The mean of AOFAS Hindfoot score improved from 48.2 preoperatively to 88.6 points at the last postoperative followup. Eighteen patients had excellent results (none, mild occasional pain), six patients had moderate pain of the foot and two patients had severe pain in evaluation with the score. Complications included superficial wound infections in two patients and a nonunion developed in one case.ConclusionsEarly isolated talonavicular arthrodesis provides excellent pain relief and prevents further progression of the foot deformities in patients with rheumatoid arthritis and tibialis posterior tendon dysfunction.

A new technique for reconstruction of the proximal humerus after three- and four-part fractures

The results of proximal humeral replacement following trauma are substantially worse than for osteoarthritis or rheumatoid arthritis. The stable reattachment of the lesser and greater tuberosity fragments to the rotator cuff and the restoration of shoulder biomechanics are difficult. In 1992 we developed a prosthesis designed to improve fixation of the tuberosity fragments in comminuted fractures of the proximal humerus. The implant enables fixation of the fragments to the shaft of the prosthesis and the diaphyseal fragment using screws, washers and a special toothed plate. Between 1992 and 2003 we used this technique in 50 of 76 patients referred to our institution for shoulder reconstruction after trauma. In the remaining 26, reconstruction with a prosthesis and nonabsorbable sutures was performed, as the tuberosity fragments were too small and too severely damaged to allow the use of screws and the toothed plate. The Constant score two years post-operatively was a mean of 12 points better in the acute trauma group and 11 points better in the late post-traumatic group than in the classical suture group. We recommend this technique in patients where the tuberosity fragments are large enough to allow fixation with screws, washers and a toothed plate.

Sciatic nerve palsy after total hip replacement

We report a case of sciatic nerve palsy following total hip replacement which has lead to a novel hypothesis to account for this complication.

The Long Oblique Revision component in revision arthroplasty of the hip

Migration of the acetabular component may give rise to oval-shaped bone defects in the acetabulum. The oblong implant is designed to fill these defects and achieve a stable cementless anchorage with no significant bone loss. We prospectively reviewed 133 oblong long oblique revision components at a mean follow-up of 9.74 years (0.6 to 14). All had been used in revisions for defects of type IIB to IIIB according to Paprosky. Aseptic loosening was the reason for revision in 11 cases (8.3%) and deep infection in seven (5.3%). The probability of implant survival over a 12-year follow-up estimated by the Kaplan-Meier method gave a survival rate of 0.85% respectively 0.90% when deep infection was excluded as the endpoint. Our study supports the use of these components in defects from IIB to IIIA. The main precondition for success is direct contact of more than half of the surface of the implant with the host acetabular bone.

Biofilm detection by the impedance method

The impedance method was used to detect bacterial layer on the surface of micro-electrodes. The interdigital electrodes arrangement was simulated by FEM to determine the detection distance of the sensor. Then, the KB-12 sensor with spacing 15 µm was selected as the most suitable sensor. For experiments, Escherichia coli was chosen as a typical representative of a biofilm creating bacterium and the bacterial growth was measured during 12 hour intervals. The impedance of the sensor KB-12 was changed by 10 percent when covered with a layer of bacteria.

Zweizeitige Operation zur Behandlung tiefer Infektionen bei Hüftendoprothesen unter Verwendung eines kanülierten Platzhalters

ZusammenfassungOperationsziel Einsetzen eines soliden antibiotikahaltigen PMMA-Platzhalters in der ersten Operation eines zweizeitigen Hüftrevisionseingriffs wegen tiefer Infektion bei Hüftendoprothese.Dadurch Vermeidung einer Beinverkürzung und Erreichen einer toxischen lokalen Antibiotikakonzentration. Indikationen Tiefe Infektion nach Hüfttotalendoprothesen, insbesondere wenn die Femurkomponente betroffen ist. Kontraindikationen Große Knochendefekte am proximalen Femur.Schlechter Allgemeinzustand, der keine Revisionsoperation mehr zulässt. Operationstechnik Entfernung beider Komponenten, ausgiebiges Débridement mit Entfernung des alten Zements. Intraoperative Formung eines kanülierten Spacers mit antibiotikahaltigem Knochenzement im Stil einer Moore-Prothese. Kanülierung mit einem Charrière-16-Redon-Drain, in den ein passender Kirschner-Draht eingeführt wird. Nach Aushärten des Zements Entfernung des Kirschner-Drahts und Kürzen des Drains. Ein Charrière-8-Drain wird in den Spacer geschoben, und die Hüfte wird reponiert. Ergebnisse Der Spacer wurde in 29 Fällen mit tiefem Hüftendoprotheseninfekt angewendet. Das Intervall zwischen Implantation des Spacers und Wiedereinbau einer Hüftendoprothese betrug 11,6 Wochen. Nach Spacerimplantation traten in zwei Fällen Reinfektionen auf, die ein zweites Débridement mit Implantation eines neuen Spacers und eine Spülung erforderten. Unsere Erfolgsrate mit dieser zweizeitigen Revisionsoperation beträgt 96,5%. Die Patienten erreichten im Harris-Hip-Score durchschnittlich 90,1 Punkte. Brüche des Spacers traten zweimal, Luxationen fünfmal auf; beide hatten keinen Einfluss auf das Endergebnis.AbstractObjective Eradication of infection through insertion of a solid antibiotic-loaded PMMA spacer during the first stage of a twostage reimplantation for deep infection to prevent shortening, to obtain a high local concentration of antibiotics in and to permit lavage of the medullary canal. Indications Deep infection after total hip arthroplasty (THA) in patients who are candidates for revision surgery, especially in instances where the infection is confined to the region of femoral component. Contraindications Large defect of proximal femur.Poor general health not allowing two procedures. Surgical Technique Extraction of both components, removal of all necrotic material and cement. Intraoperative manual modeling of a cannulated spacer using bone cement premixed with antibiotics, its shape resembling a Moores prosthesis. The spacer is shaped around a size 16 drain into which a corresponding Kirschner wire is inserted. Once the spacer is completely set, the Kirschner wire is removed and the drain shortened. A size 8 lavage drain tube is then inserted into the spacer and the hip reduced. Results We used the spacer in the treatment of 29 patients with infected THA. The interval between spacer implantation and insertion of the total hip implants was 11.6 weeks. Reinfection after implantation of the spacer was observed twice necessitating a second debridement, implantation of a new spacer, and lavage. Success rate of two-stage revision was 96.5%. The Harris hip score reached an average of 90.1 points. Breakage of the spacer was observed twice, and dislocation occurred in five patients; both did not affect the final result.

Treatment of orthopedic infections caused by resistant staphylococci.

During 1999–2005 we treated 15 patients with linezolid for relevant infections of locomotion apparatus (7 cases with endoprosthesis infection, 5× osteomyelitis and 3× another infection). With the exception of one case the antibiotic therapy was always combined with appropriate surgical intervention. Average period of linezolid administration was 26 d; linezolid was applied from the beginning intravenously on average for 10 d, and then orally for 16 d (average). There were no undesirable effects in the file. Success rate reached 86.6 %. MRSA strains were proved by standard methods: growth on Mueller-Hinton agar with increased concentration of NaCl and 2 mg/L of oxacilline, and measuring inhibitory zones around cephoxitine disk. The sensitivity to other antibiotics was specified by disk-diffusion test; that to linezolid was verified by E-test. Linezolid represents a medical reserve for the treatment of multiresistant Gram-positive infections or for emergencies, when allergy onset, high toxicity risk, intolerance,etc. do not allow to use other,in vitro effective, antibiotics.

Ankle block implemented through two skin punctures.

Background: Recently, peripheral nerve blocks have increasingly been used in orthopedic surgery. The foot block is an alternative for anesthesia in cases of forefoot and midfoot operations. We propose a modification of the block technique due to potential difficulties concerning the tibial nerve. Materials and Methods: The spatial position of the tibial nerve in the neurovascular bundle, proximal to entering the tarsal tunnel and sural nerve behind lateral malleolus was measured on 60 dissected preparations. Modification of the block technique was proposed. A tibial nerve block was administered by inserting a needle, at an area above the upper edge of the heel bone, tangential to the Achilles tendon. The needle was then withdrawn and redirected to the frontal plane and inserted through the tissue, anterior to the Achilles tendon and laterally behind the lateral malleolus to block the sural nerve. A block of the saphenous nerve superficial and deep peroneal nerves was implemented by needle insertion subcutaneously two centimeters proximal to the crest of the ankle joint. The technique was then evaluated in the clinical part of the study in 84 operative procedures. Results: The tibial nerve is located 21.1 mm ± 2.1 mm from the medial aspect of the Achilles tendon and 11.6 mm ± 1.3 mm deep in the neurovascular bundle. The distance from the posterior margin of the lateral malleolus to the sural nerve is 18.3 mm ± 1.9 mm. We achieved a 93% success rate in implementation of the complete foot block in 84 operations. Conclusion: The technique, proposed in the anatomical portion of the study and evaluated in the clinical part, had a similar success rate when compared to techniques published in the literature. Though comparable to currently used techniques, this technique provides easier positioning of a patient and a complete block of the foot can be done with two skin injection sites. Level of Evidence: IV, Case Series