Closed reduction and percutaneous Kirschner wire fixation for the treatment of dislocated calcaneal fractures: surgical technique, complications, clinical and radiological results after 2-10 years.

INTRODUCTION: To reduce complications, a minimally invasive technique for the treatment of dislocated intraarticular fractures of the calcaneus was used. Therefore previously described closed reduction and internal fixation techniques were combined and modified. MATERIALS AND METHODS: Sixty-seven out of 92 calcaneal fractures could be retrospectively evaluated with an average follow-up time of 5.7 years (minimum 2-10 years follow-up). For radiographic evaluation, plain radiographs and CT scans were obtained. The Zwipp score was used for clinical evaluation. Sanders type II, III and IV fractures were diagnosed. RESULTS: Length of surgery averaged 61 min (range 20-175 min). The incidence of subtalar arthritis was correlated to the severity of fracture. Böhler's angle was restored in 70.1% (47 of 67) of the cases. On the last follow-up evaluation the average Zwipp score was 130 points (range 48-186 points). The majority (77.7%) of patients were content with their treatment result. The rate of significant complications was 6.5%. DISCUSSION: Compared to open techniques the presented minimally invasive technique showed comparable results with a low rate of serious complications and is a viable alternative for the treatment of intraarticular, dislocated calcaneal fractures.

[Shaft lengthening in hip replacement: experimental studies on bending stiffness]. / Stielverlängerung bei Hüftprothesenrevisionen: Experimentelle Untersuchungen zur Biegesteifigkeit.

BACKGROUND: Cortical atrophy of the proximal femur can be seen after wearing a total hip prosthesis for several years because loads are borne distally at the prosthesis tip. To achieve stable prosthesis implantation on the one hand and proximal bone regeneration on the other hand in hip revision arthroplasty, lengthening of the shaft component distributes loading forces to the femoral shaft first. It concentrates them to the proximal femur later through a higher elasticity. METHODS: In a three-point bending study the bending stiffness of an elastic slotted hip prosthesis shaft lengthening (HSL) was compared with that of the Synthes universal femoral nail (MN) and the unslotted HSL. RESULTS: The slotting of the elastic HSL has a significant influence on its bending stiffness; it lies 1,287 N/mm (76%) over that of the MN, but 1,855 N/mm (38%) under that of the unslotted HSL. Altogether the slotted HSL is rather more comparable to the MN than to the unslotted HSL regarding its bending conduct. CONCLUSION: The results confirm the elasticity of the slotted HSL in the style of conventional intramedullary nailing and encourage-above all in the context of previous clinical studies-its further use.

Friction of ceramic and metal hip hemi-endoprostheses against cadaveric acetabula.

INTRODUCTION: Studies of hip arthroplasty have dealt mainly with total endoprosthesis, while tribology measurement values of hemi-endoprosthetic implants are rare. The small amount of experimental tribological data concerning materials of hemi-endoprosthetic implants in the form of pendulum trials, animal experiments, in vivo measurements on human hip joints and pin on disc studies report friction coefficients between 0.014 and 0.57; the friction coefficients measured in fresh human cadaver hip joints were determined between 0.001 and 0.08. MATERIALS AND METHODS: The HEPFlEx-hip simulator was constructed to test the friction coefficients of unipolar femur head hemi-endoprostheses made of metal or ceramic against fresh cadaveric acetabula. Its plane of movement is uniaxial with a flexion-extension movement of +30/-18 degrees . The force is produced pneumatically dynamic with amounts of 2.5 kN. Newborn calf serum serves as a lubricant. We mounted 20 fresh porcine acetabula and 10 fresh human cadaver acetabula in the HEPFlEx-hip simulator and compared the two unipolar femur head hemi-endoprostheses (metal vs. ceramic). RESULTS: The mean friction coefficients against porcine acetabula were micro=0.017-0.082 for ceramic and micro=0.020-0.101 for metal; against human cadaver acetabula micro=0.017-0.083 for ceramic and micro=0.019-0.118 for metal. The frictional coefficient deltas (metal-ceramic) values of all measurements were Deltamicro=0.004 for porcine acetabula and Deltamicro=0.001 for cadaver acetabula. Box-plots graphics document significantly lower frictional coefficients of the ceramics. CONCLUSIONS: The lower frictional coefficients of ceramic compared to metal against fresh cadaveric acetabula may have a clinical impact on the process of the protrusion of the corresponding femoral head through the acetabulum.

[The HEPFIEx simulator, a device for determination of friction between femur head prosthesis and cartilage]. / Der HEPFIEx-Simulator, eine Apparatur zur Bestimmung der Reibzahlen zwischen Hüftkopf-Prothesen und Knorpel.

We describe a device designed to investigate friction between various femoral head prostheses and human acetabula. It enables not only the determination of friction and the relevance of the play between the femoral head and acetabulum, but also the evaluation of the kinematic behaviour of bipolar prostheses. In the simulator, the various femoral head prostheses are placed on a special cone and tested against a human cadaveric acetabulum. The swiveling range of the device is uniaxial, and the swiveling angle is +/- 35 degrees. The maximum force produced pneumatically is 5kN. Testing of the simulator with a TEP was successful and friction-coefficients of < 0.1 were measured, as are reported in the literature.

Friction in hip hemiendoprostheses. Review of literature and own model using cadaveric acetabula.

The science of tribology concerning hip arthroplasty has mainly dealt with total endoprosthesis, whereas measurement values of hemiendoprosthetic implants are rare. The small amount of experimental tribologic data concerning hemiendoprosthetic implants in the form of pendulum trials, animal experiments, in vivo measurements on human hip joints and pin on disc studies will be reviewed in the following work. The reported frictional coefficients in these studies were between 0.014-0.57. In order to test the friction coefficients of different femur head hemiendoprostheses (unipolar ceramic- and metal heads) against fresh cadaveric acetabula, the HEPFlEx-hip simulator (Hemi-EndoProsthesis Flexion Extension) was developed. In the simulator, the various hemiendoprosthetic heads are placed on a special cone and tested against a cadaver acetabulum cast in MCP 47 woodmetal. The plane of movement of the apparatus is uniaxial with a flexion-extension movement of 35 degrees. The force is produced pneumatically with amounts of up to 5 kN. Newborn calf serum serves as a lubricant. A PC collects the data from torque-, force-, and angle-sensors on-line and allows the simultaneous processing and visualization of the data. The frictional coefficients produced by the different head materials and the relevance of the play between the hemiendoprothesis head size and acetabulum can be determined. Preliminary results showed that the mean friction coefficient at 1 kN loading was =0.024-0.063 for ceramic against cartilage and =0.033-0.075 for metal against cartilage. (Hip International 2002; 2: 126-34).

Long-term results after operative treatment of femoral neck fractures with ceramic head prostheses.

From 1985-1990, a total of 277 elderly patients underwent hemiarthroplasty using a ceramic head prosthesis. Average patient age was 81.7 years. Of these, 77 patients were available for follow-up examination in 1993. A standardized score was calculated assessing activity, gait, and hip pain; the average score was 58 out of 78 possible points. Three patients had hip pain, and in 4 patients, radiographic examination revealed protrusio acetabuli. Two of 4 patients underwent revision surgery for replacement of the cup, leaving the stem in situ. Because of the small number of prosthetic-related complications, hemiarthroplasty using a ceramic head prosthesis is the recommended surgical treatment for femoral neck fractures in elderly patients. In the rare patient with protrusio acetabuli, revision surgery can be performed to replace the cup, leaving the stem in situ.

Endoscopic carpal tunnel release: results with special consideration to possible complications.

Single-portal endoscopic carpal tunnel release (Agee technique) was carried out in 148 patients. Of these, 100 were examined clinically and electrophysiologically 1 day before surgery and 1 and 3 months thereafter. Ten patients experienced transient ulnar neuropraxia and two patients complained postoperatively of intense pain in the middle and ring fingers. Three patients suffered residual symptoms. In one of these an incomplete release of the distal portion of the retinaculum flexorum was suspected and later confirmed by magnetic resonance imaging. Another patient had applied for pension due to problems associated with a vertebral fracture in addition to his carpal tunnel symptoms. A third patient with residual symptoms was rheumatic, and upon reexamination 6 months later he was virtually symptom free. Five of the 148 operations were converted to an open procedure due to poor visualization. A review of literature on carpal tunnel release (biportal Chow technique and uniportal Agee technique) uncovered 31 intra- and postoperative complications, including 14 affecting nerve structures, 2 tendon structures, 2 bony structures, and 9 the surrounding tissues. We discuss the most common complications, considering in particular the anatomical characteristics in the carpal tunnel region.

Is there still an indication for operative treatment of femoral neck fractures with a ceramic hemiprosthesis? Four-year results.

From 1985 to 1995, 417 patients with dislocated medial femoral neck fractures (Garden III-IV) were treated with hemiarthroplasty using a Biolox ceramic head. The average patient age at the time of operation was 81.5 years. A total of 140 survivors was available for follow-up examination with a mean prosthesis longevity of 55.8 months. The Harris hip score recorded a mean of 70.6 points. At the time of follow up, 5 patients had severe hip pain, and in 8 the roentgenographic examination revealed protrusio acetabuli. Five of these 8 patients underwent revision surgery for replacement of the cup, leaving the stem in situ.

[Osteoid osteoma of the capitate: diagnosis and therapy of a rare cause for wrist pain. Case report and review of the literature]. / Osteoidosteom im Os capitatum: Diagnostik und Therapie einer seltenen Ursache für Handgelenkschmerzen. Fallbericht und Literaturübersicht.

Occasionally, bone tumors are the source of wrist pain. This is particularly true of osteoidosteoma, which are easily overlooked or diagnosed very late. We present a case report including clinical and radiological findings as well as MRI, surgical treatment, and a review of the current literature.

Pigmented villonodular synovitis of the shoulder: review and case report.

Pigmented villonodular synovitis (PVNS) as reviewed in detail elsewhere most frequently involves the knee and finger synovial structures; shoulder involvement is rare: A search through the English literature yielded 18 publications describing 25 cases of PVNS affecting the shoulder joint. Analyzing these reports we found the clinical and radiological findings generally to be nonspecific, often mimicking a malignancy, as in the case presented here of a 16-year-old boy with painful swelling in the area of the left proximal humerus. Magnetic resonance imaging showed a suspected malignant soft tissue mass involving the shoulder capsule and measuring 7.5 x 6 x 4 cm. Preoperatively the patient could recall no trauma; however, postoperatively he did report a distortion trauma of the affected shoulder following a bicycle accident. Intraoperatively, two tumors were found infiltrating the axillary vessels and nerve and tendon structures originating in the capsule of the shoulder joint. Rapid sections of the tissue revealed no signs of malignancy; further pathohistological examination revealed localized PVNS. Preoperatively, the shoulder joint was not suspected as the primary site of origin of the tumor because the patient had no complaints or functional deficits of the shoulder. The clinical presentation of such a PVNS lesion over the proximal humerus is unusual and to date has only twice been described in the literature.

[Efficacy of ultrasound controlled direct reposition of fragments of the posterior vertebral body facet]. / Die Effizienz der sonographisch kontrollierten direkten Reposition von Fragmenten der Wirbelkörperhinterkante.

To calculate canal compromise and decrease of midsagittal diameter caused by retropulsion of fragments into the spinal canal we analyzed the pre- and postoperative computed tomographies of 32 patients with unstable thoracolumbar burst fractures treated by USS (universal spine system). Our intention was to examine the efficiency of ultrasound guided repositioning of the dispaced fragments which was performed in all 32 cases. We found a clear postoperative enlargement of canal area (ASP preoperatively 55%, postop. 80%) and midsagittal diameter (MSD preop. 58%, postop. 78%). 10 of 13 patients presented a postoperative improvement of neurological deficit, no neurological deterioration occurred. Fractures with neurological deficit showed more canal compromise (52%) and less midsagittal diameter (MSD compromise 51%) than those without (40% or 39%). There was no correlation between the percentage of spinal canal stenosis and the severity of neurological deficit. Below L 1 the spinal canal is greater than between Th 11 and L 1, so a more important spinal stenosis is tolerated. In case of unstable burst fractures with neurological deficit the ultrasound guided spinal fracture reposition is an effective procedure concerning the necessary improvement of spinal stenosis: an additional ventral approach for the revision of the spinal canal is unneeded. In fractures without neurologic deficit the repositioning of the displaced fragments promises an avoidance of long-term damages such as myelopathia and claudicatio spinalis.

Ultrasound-guided spinal fracture repositioning.

The management of narrowing spinal fragments in the operative treatment of spinal fractures remains an open question, in particular when the procedure is performed by a posterior approach. This article describes the use of intraoperative ultrasonography during spinal surgery. From 1990 to 1997, 116 spinal fractures were treated operatively at our clinic. Stabilization of the spine was achieved with the AO fixateur interne and the AO USS, respectively (Synthes, D-79224, Umkirch, Germany). For 60 cases who had a fractured posterior vertebral surface dislocated into the spinal canal, we used intraoperative ultrasonography to monitor the repositioning of the narrowing fragments. The patients underwent pre- and postoperative computed tomography scans (CT). In six cases, color-coded duplex sonography was performed intraoperatively to view the A. spinalis anterior. In 58 cases, the spinal canal and the fractured posterior surface of the vertebrae were visualized successfully. The sonographic image was inconclusive in two cases with severely damaged fragments. Identical findings were observed on the intraoperative ultrasound image after completion of repositioning and on the postoperative CT scan. In six cases, the A. spinalis anterior was viewed by color-coded duplex sonography with a different flow before and after fracture repositioning. Intraoperative ultrasound is a valuable means of monitoring the restoration of the spinal canal by a posterior approach. The method is easy to perform and can be repeated as often as required. Color-coded duplex sonography allows further visualization of the A. spinalis anterior.

[Traumatic thrombosis of the distal ulnar artery (hypothenar hammer syndrome) in a golf player with an accessory muscle loop around Guyon's canal. Case report]. / Traumatische Thrombose der distalen A. ulnaris (Hypothenar-Hammer-Syndrom) bei einem Golfspieler mit akzessorischer Muskelschlinge um den Guyonschen Kanal. Fallbericht.

Arteriography of a 34-year-old golf player with M. Raynaud symptoms of his left hand revealed filling defects in the digital arteries II to IV fingers associated with corkscrew-like configuration of the ulnar artery in Guyon's space. The preoperative workup including 50 clinical laboratory tests searching for connective tissue diseases, vasculitis, and haematological disorders was without pathological findings; more central embolic sources were excluded angio- and cardiologically. MRI-scan demonstrated an anomalous muscle at the level of the hamate hook located underneath the M. palmaris brevis forming a sling around the ulnar artery. Surgery showed the ulnar artery distal to the anomalous muscle dilated with fibrotic thickening and intraluminal thrombosis. The involved A. ulnaris segment was resected and an interpositional vein graft performed. Histopathologic sections showed fibrosis of the arterial wall with intraluminal thrombosis and elastica fragmentation indicating traumatic genesis (hypothenar-hammer syndrome). We suspect intensive golf playing with the grip style and repetitive movements leading to pressure injury of the hypothenar area and the underlying ulnar artery. Contraction of the anomalous muscle belly may have additionally compressed the artery slowing down the arterial flow and accelerating the thrombosis.

[Magnetic resonance tomography examination of thoracolumbar spinal fractures after fixateur interne stabilization]. / Kernspintomographische Untersuchung thorakolumbaler Wirbelfrakturen nach Fixateur-interne-Stabilisierung.

To analyse the possible injuries of vertebral segments, especially the disc, after unstable thoracolumbar fractures stabilised with AO internal fixator, we performed magnetic resonance imaging (MRI) of the traumatised region after implant removal. There were two aspects of disc degeneration (DD):(1) biochemical changes and (2) structural damage. MRI detects biochemical processes as one aspect of DD that is often small even in the presence of greater structural damage of the nucleus pulposus caused by fracture. None of the patients presented with structural failure of the anulus fibrosus, which is the essential structural component of the vertebral segments with regard to stability. We observed biochemical changes more often in the lower of the two fracture-adjacent discs and alterations of discal shape more often in the upper of the two, whereas loss of height concerned both discs to approximately the same degree. The supporters of upper-disc resection in thoracolumbar fractures justify their procedure among other things with the structural disc damage, such as alteration of shape and loss of height (altogether more frequent in the upper disc). Our observations that a disc with a structurally altered nucleus pulposus can be biochemically intact and can show an intact anulus fibrosus are arguments in favour of disc preservation. With regard to the upper disc, the widespread opinion that complete and regular disc damage requires a resection has to be revised. The question of whether the lower disc should be resected more often because of its greater biochemical changes cannot be answered by the present study alone. Besides the excellent static information in all anatomical structures of the vertebral column available by MRI, a repeat examination in a prone position yields dynamic information on the spinal cord in the case of suspected dorsal adhesions.

[Determination of bone quality before spinal instrumentation--value of different in vivo methods]. / Bestimmung der Knochenqualität vor Wirbelsäuleninstrumentation--Stellenwert verschiedener in vivo-Methoden.

OBJECTIVE: The present investigation should elucidate which assessment technique for bone quality is most appropriate to estimate preoperatively fixation strength of instrumental spine fusions. METHODS: VDS-screw fixation strength in 50 human cadaveric vertebral bodies was approximated by means of pullout force assessment. Bone quality was assessed by Dual Energy X-ray Absorptiometry (DEXA), Quantitative Computed Tomography (QCT), MRT and histomorphometry. For each of these techniques, correlation with axial pull out force strength was investigated. RESULTS: Highest correlation was found for cancellous bone density (QCT) (r = 0.72; p < 0.001) and DEXA (r = 0.70; p < 0.001). MRT, cortical bone density (QCT) and histomorphometry just slightly correlated with pullout force strength. CONCLUSIONS: Absorptiometrical techniques like QCT and DEXA are most appropriate to estimate VDS-screw fixation strength preoperatively.

Minimally invasive plate fixation in femoral shaft fractures.

Bridge-plating with its advantages in terms of vascularity and bone healing is a well established procedure today in the treatment of comminuted femoral fractures. Bridge-plating means that the fracture site is not interfered with during the operative procedure. This paper introduces a surgical technique in which the plate is inserted through isolated proximal and distal incisions only, behind the vastus lateralis. Alignment is secured by the plates, the fracture site remains untouched, fixation and screw insertion is restricted to the proximal and distal main fragments. Longitudinal femoral fractures extending right into the trochanteric and or condylar areas are the main indication for minimally invasive plate fixations with angled blade plates or condylar screws since fractures which are restricted to the diaphyseal area are mostly treated by nailing today. The surgical trauma resulting from plating by proximal and distal incisions only is less than that associated with conventional techniques. Indirect reduction of femoral fragments is much easier since the integrity of the surrounding muscles and soft tissue is preserved, the fragments often being reduced simply by traction. Adjustment of rotation is an essential aspect requiring careful attention. For special indications, namely comminuted fractures affecting a large part of the femur and extending into the trochanteric or condylar areas, insertion of the plate via proximal and distal incisions only is a further development in bridge-plating which minimizes surgical trauma and operation time.

[Late functional outcome of surgically treated mid-hand fractures]. / Funktionelle Spätergebnisse nach operativ behandelten Mittelhandfrakturen.

The aim of surgical intervention for the treatment of metacarpal fractures is to restore the best possible function. This study of 61 patients who were treated utilizing different osteosynthesis techniques demonstrates out-standing long-term results. Conservative treatment may be adaeqaute for the treatment of uncomplicated and minimally dislocated fractures. For serial fractures and fractures involving joints, however, there is no alternative to osteo-synthesis.

[Complications of endoscopic retinaculum dissection]. / Komplikationen der endoskopischen Retinakulumspaltung.

Reviewing the literature on endoscopic carpal tunnel release (biportal Chow-technique and uniportal Agee-technique), we found 31 different intra- and postoperative complications. Of these, 14 affected nerve structures, four vessel structures, two tendon structures, two bony structures, and nine surrounding tissues. The most common complications were analyzed taking anatomical and pathological variations of the carpal tunnel into consideration. In our own prospective series of 88 endoscopic releases of the carpal tunnel using the Agee technique, we had eleven complications: one patient suffered residual symptoms, five patients experienced transient ulnar neurapraxia, and one patient complained of intense pain in the middle- and ringfinger after the operation. In four cases, intraoperative change of technique from endoscopic to open became necessary, due to poor visualization.