Does a polyaxial-locking system confer benefits for osteosynthesis of the distal fibula: A cadaver study

BACKGROUND

In plate osteosynthesis involving the distal fibula, antiglide plating is superior to lateral plating in terms of the biomechanical properties. The goal of this study was to examine whether polyaxial-locking implants confer additional benefits in terms of biomechanical stability.

METHODS

Seven pairs of human cadaveric fibulae were subjected to osteotomy in a standardized manner to simulate an uncomplicated Weber B fracture. The generated fractures were managed with a dorsolateral antiglide plate. To this end, one fibula of the pair was subjected to non-locking plating and the other to polyaxial-locking plating. Biomechanical tests included quantification of the primary bending and torsional stiffness. In addition, the number of cycles to failure in cyclic bending loading were determined and compared. Bone mineral density was measured in all specimens.

RESULTS

Bone mineral density was comparable in both groups. Primary stability was higher in the polyaxial-locking group under torsional loading, and higher in the non-locking group under bending loading. The differences, however, were not statistically significant. All specimens except for one fixed-angle construct failed the cyclic loading test. The number of cycles to failure did not differ significantly between polyaxial-locking and non-locking fixation.

CONCLUSION

In a cadaveric Weber B fracture model, we observed no differences in biomechanical properties between polyaxial-locking and non-locking fixation using an antiglide plate. Based on the biomechanical considerations, no recommendation can be made regarding the choice of the implant. Further biomechanical and clinical studies are required.

CLINICAL RELEVANCE

Information on the behavior of polyaxial-locking plates is relevant to surgeons performing internal fixation of distal fibula fractures.

[Plantar approach to hindfoot arthrodesis with compressed angle stable locking option]

BACKGROUND

Tibiotalocalcaneal arthrodesis is indicated in severe combined arthritis of the upper and lower ankle joints and otherwise untreatable malpositioning of the hindfoot.

CONCLUSION

Currently available arthrodesis nails have a hindfoot valgus bend which allows the anatomy to be more faithfully reproduced and respected. Anatomical investigations show the endangered structures during retrograde arthrodesis nailing. The valgus bend of the arthrodesis nail necessitates a corresponding correctly placed opening in the calcaneus and talus as the entry point for the nail. A locking screw in the calcaneus running from posterior to anterior increases the stability and is now taken into consideration for nearly all designs of arthrodesis medullary nails. The compression mechanism can be used for apposition and pressing the arthrodesis surfaces together and locking in the hindfoot should be carried out in an angle stable fashion. Augmentation of the locking screws in the calcaneus with bone cement can be an option as a salvage procedure in revision cases.

[Therapy of acute ankle sprain: one-year results of primary conservative treatment]

INTRODUCTION AND AIM

Ankle sprains (supination-eversion injury) have a high incidence. Conservative treatment is generally the method of choice. This study is intended to evaluate the 1-year results of a standardised treatment protocol.

MATERIAL AND METHODS

A total of 416 patients who had suffered an ankle sprain were included into this study. All of them had undergone primary conservative treatment. A total of 66 of them (15.9 %) had undergone operative treatment within one year after injury. The indications for operation were persistent pain, swelling or persistent instability. In 33 patients an arthroscopy for evaluation of the joint and debridement was used. In the case of a persistent instability 22 ligament augmentations (Kuner periostal flap) and 11 peroneus tenodesis (Watson-Jones) were performed. The evaluation was done by using the AOFAS score ("Ankle Hindfoot Scale" of the American Orthopedic Foot and Ankle Society).

RESULTS

A 1-year follow-up was possible in 96.4 % of the patients. The mean AOFAS score was 77.1 ± 10.5 points after conservative treatment. Those patients who needed an arthroscopic debridement had a slightly better outcome (AOFAS score 79.5 ± 10.2 points). Patients who had undergone stabilisation operations tended to have the best outcome (p = 0.093). The AOFAS score was 79.6 ± 15.4 points in patients after periostal flap augmentation, respectively, 83.0 ± 7.4 points after peroneus tenodesis.

CONCLUSIONS

The results confirm the benefit of conservative treatment in acute ankle sprain. Even so about 15 - 20 % of the patients still suffer from persistent pain, swelling or instability. The indication for operative intervention should be made relatively broadly. Most of these patients profit from the operation. Above all, after ankle sprain patients need a continuous re-evaluation by a specialised centre during the first post-injury year.

In vitro phenotypic modulation of chondrocytes from knees of patients with osteochondritis dissecans: implications for chondrocyte implantation procedures

We attempted to characterise the biological quality and regenerative potential of chondrocytes in osteochondritis dissecans (OCD). Dissected fragments from ten patients with OCD of the knee (mean age 27.8 years (16 to 49)) were harvested at arthroscopy. A sample of cartilage from the intercondylar notch was taken from the same joint and from the notch of ten patients with a traumatic cartilage defect (mean age 31.6 years (19 to 52)). Chondrocytes were extracted and subsequently cultured. Collagen types 1, 2, and 10 mRNA were quantified by polymerase chain reaction. Compared with the notch chondrocytes, cells from the dissecate expressed similar levels of collagen types 1 and 2 mRNA. The level of collagen type 10 message was 50 times lower after cell culture, indicating a loss of hypertrophic cells or genes. The high viability, retained capacity to differentiate and metabolic activity of the extracted cells suggests preservation of the intrinsic repair capability of these dissecates. Molecular analysis indicated a phenotypic modulation of the expanded dissecate chondrocytes towards a normal phenotype. Our findings suggest that cartilage taken from the dissecate can be reasonably used as a cell source for chondrocyte implantation procedures.

[Comparative study on the strength of different mechanisms of operation of multidirectionally angle-stable distal radius plates]

INTRODUCTION

Polyaxial angle-stable plating is thought to be particularly beneficial in the management of complex intra-articular fractures of the distal radius. The present study was performed to investigate the strength of polyaxial locking interfaces of distal radius plates.

MATERIAL AND METHODS

We tested the polyaxial interfaces of 3 different distal radius plates (2.4 mm Variable Angle LCP Two-Column Volar Distal Radius Plate, Synthes, Palmar Classic, Königsee Implantate and VariAx Plate Stryker). The strength of 0° and 10° screw locking angle was obtained during static loading.

RESULTS

The strength of Palmar Classic with a 0° locking angle is significantly the best of all tested systems. With a 10° locking angle there is no significant difference between Palmar Classic, Two column Plate and VariAx Plate.

CONCLUSION

The strength of polyaxial interfaces differs between the tested systems. A reduction of ultimate strength is due to increases of screw locking angle. The design of polyaxial locking interfaces should be investigated in human bone models.

[Sustentaculum tali screw placement for calcaneus fractures--different navigation procedures compared to the conventional technique]

AIM

Precise placement of the sustentaculum tali screw is essential for fixation of calcaneus fractures to achieve the best fixation strength. In the clinical practice, this procedure is demanding due to the complex anatomic configuration of the calcaneus and the limited visualisation in the intraoperative fluoroscopic images. The aim of this study was an evaluation of the accuracy for the sustentaculum tali screw placement by using different navigation procedures compared to the standard procedure. The different navigation specific workflows were evaluated and the feasibility of each procedure proven in clinical applications.

METHOD

Eight sustentaculum screws per group were placed in an artifical Synbone model. Different navigation procedures were evaluated: 2D-fluoroscopy (group I), 3D-fluoroscopy (group II), fluoro-free (group III) and compared to the conventional screw placement without navigation (group IV). For each screw the time of fluoroscopy and the duration of the procedure were measured. The accuracy was evaluated postoperatively by computed tomography using axial slices and coronary as well as sagittal reformations. Furthermore, the workflow of each navigation procedure was analysed and proven in clinical applications.

RESULTS

In the experimental setup, no radiation exposure was mandatory for the conventional and fluoro-free procedures, whereas mean fluoroscopy times of 17 +/- 1.03 und 66.8 +/- 0.9 were measured for 2D- and 3D-navigation procedures. In line with this, the overall mean procedure times for the screw placement were 1.26 +/- 0.05 (group IV), 3.49 +/- 0.26 (group III), 13.32 +/- 0.49 (group I) und 19.04 +/- 1.41 minutes (group II). No significant differences were observed for the accuracy of screw placement. In the clinical practice a better orientation was achieved by use of a navigation system. The fluoro-free procedure can be easily integrated into the common operation workflow, whereas the workflow of both image-based navigation procedures is technically demanding.

CONCLUSION

Navigation procedures seem to be helpful for the precise placement of sustentaculum tali screws in cases of operative calcaneus fracture fixation. The kind of application to be used depends on the infrastructure of the department and the navigation-experience of the operating room team. Whereas the fluoro-free procedure is intuitive in use, the 2D-navigation does not justify the extra efforts. The 3D-procedure is the recommended application for surgeons familiar with navigation, providing the best orientation due to the slice image visualisation in all three dimensions.

[Necrotizing fasciitis after "banal" back pain. An unusual course of a retrocoecal appendicitis and its sequellae]

Necrotizing fasciitis is a life-threatening disease which can only be successfully treated by an interdisciplinary team. An immediate and radical debridement with opening of all compartments and debridement of the affected fascia is the basis for a successful therapy. We report about the treatment of a 21-year-old man who was taken to hospital due to "banal" back pain which was caused by a perforated appendicitis. In only 2 days necrotizing fasciitis developed which spread out over the complete right leg.

[Preservation of hip prosthesis with local surgical revision and creation of a fistula persistens : an option for palliative treatment of periprosthetic infection in old, polymorbid patients?]

BACKGROUND

The number of implanted hip prostheses is increasing constantly. At the same time the patients are becoming older and older. Thus, also patients with periprosthetic infections are older and therefore sicker. Uniform guidelines for the treatment of infected arthroplasties are controversial. Empirical studies show that the explantation of the original prosthesis and implantation of a revision may be the option with the greatest chance of success. These very aggressive procedures may overburden the old, polymorbid patient. The aim of this study was to ascertain whether or not keeping the hip prosthesis in combination with local debridement, formation of a permanent fistula and long-term administration of antibiotics is a possible option for the treatment of infected hip prostheses in old and polymorbid patients.

PATIENTS

Between 01.01.2004 and 28.01.2007, 12 patients with periprosthetic infection after hip arthroplasty (PIH) were treated. Their average age was 79.8 years. Eleven patients were rated ASA III preoperatively. The prostheses were on average 23.8 weeks old when the first signs of infection occurred. In 10 cases the infection was caused by Staphylococcus (MRSA 3x). The main comorbidities were hypertension, diabetes, coronary heart disease and thyroid malfunction.

RESULTS

After a mean 8.83 months, six patients were deceased (average age 85.50 years). In five of the remaining six patients the fistula worked without any problem. In one case the fistula was occluded. None of the patients showed any sign of acute infection. All were able to walk with full weight-bearing on the affected hip.

CONCLUSION

Restricting the indication to old, polymorbid patients, preservation of the arthroplasty in combination with local surgical debridement, permanent fistula and long-term systemic administration of antibiotics seems to be an alternative to explantation of the prosthesis with consecutive revision arthroplasty or resection arthroplasty.

[Evaluation of cartilage defects in the knee: validity of clinical, magnetic-resonance-imaging and radiological findings compared with arthroscopy]

BACKGROUND

The study was aimed to evaluate the validity of clinical, radiological and MRI examination for cartilage defects of the knee compared with arthroscopic finding.

METHODS

Seven-hundred seventy-two patients who were suffering from knee pain over more than 3 months were evaluated clinical (grinding-sign) and with radiography and magnetic resonance imaging (MRI) and subsequent arthroscopy.

RESULTS

The grinding sign had a sensitivity of 0.39. The association of a positive grinding test with high grade cartilage defects was significant (p<0.000). In 97.4% an intact chondral surface correlated with a normal radiological finding. Subchondral sclerosis, exophytes and a joint space narrowing was significantly associated with high grade cartilage defects (p<0.000). The accuracy of MRI was 59.5%. The MRI resulted in an overestimation in 36.6% and an underestimation in 3.9%. False-positive results were significant more often assessed in low-grade cartilage defects (p<0.000).

CONCLUSIONS

Clinical signs, x-ray imaging and MRI correlate with arthroscopic findings in cases of deep cartilage lesions. In intact or low-grade degenerated cartilage often results an overestimating of these findings.

Differenzierte Behandlung beidseitiger distaler Tibiapseudarthrosen

Operative treatment of distal tibial fractures remains a challenge for the surgeon even today. The soft tissues demand atraumatic operative techniques, although an anatomical reduction of the articular fracture component is mandatory. The nonunion rate increases with disturbed local blood supply, widened fracture gap, unstable fixation. If a nonunion occurs, an individual treatment concept is required, so that even difficult situations can be successfully managed, as described in our case with bilateral tibial nonunions.

Retrograde intramedullary nailing in tibiotalocalcaneal arthrodesis: a short-term, prospective study

In this prospective study, tibiotalocalcaneal arthrodesis was performed in 29 patients with a retrograde femur nail (Interlocking Compression Nail; Stryker Trauma, Schönkirchen, Germany) inserted through a plantar approach. Patients were evaluated by a standardized follow-up examination using the American Foot and Ankle Society ankle-hindfoot scale and the main criteria of the short-form health survey (36 items). Special emphasis was placed on surgical approach, bony consolidation, and postoperative quality of life. Solid fusion was achieved in 90% of the patients after a mean follow-up of 25 months. Twenty-two patients (76%) showed primary bone healing after an average of 5.2 months; a delayed union was observed in 7 patients. In 79% of the patients, pain was reduced effectively and quality of life substantially improved with the intramedullary nail arthrodesis. The average ankle-hindfoot score improved from 46 (range, 41-53) to 71 (range, 49-83) points. Complications occurred in 6 patients (21%), including 2 deep infections, 3 nonunions, and 1 case of postoperative flexion deformity. The authors found retrograde intramedullary nailing in tibiotalocalcaneal arthrodesis to be an effective technique in obtaining solid fusion, an effective relief from pain, and an improvement of quality of life.

[Fractures of the lower leg in professional skiers]

Fractures of the lower leg due to skiing accidents remain an important concern. Few studies have focussed on the special demands of professional athletes who sustain these injuries. We present our experience with three cases of lower leg fractures in competitive professional downhill skiers and discuss management and treatment concepts. We performed limited reamed compression nailing in all the patients presented because it offers the advantages of high mechanical stability and optimized fragment apposition. Plate osteosynthesis of the fibula is not required in most typical fractures. All patients resumed ski training. Two of them returned to World Cup. Only one achieved her pre-injury World Cup level of performance and success. In conclusion, a successful return for professional skiers with lower leg fractures is feasible using an optimized treatment strategy.

Die Technik der tibiotalaren Arthrodese mit Kompressionsmarknagel

Tibiotalar arthrodesis still remains the primary choice of treatment for disabling ankle arthropathy since the results of ankle arthroplasty are not yet convincing. Numerous operative techniques have been described, with an increasing trend towards the use of internal fixation and compression. Using an intramedullary compression nailing technique, 137 tibiotalar fusions were performed at our hospital. The special design of the nail allows distal interlocking in the talus and dynamic axial compression with high primary stability. With correct joint axis, only the cartilage joint surfaces were removed. For axis correction the corresponding bony joint surfaces were also resected. We also performed a dowel technique with bone grafting from the lateral malleolus. We examined 110 of the 137 patients during follow-up. A primary union could be achieved in 99 cases (90.0%). A further six cases (5.5%) healed after recompression and bone grafting. Nonunion remained in five cases (4.5%). Operative complications included one tibial shaft fracture and one hematoma. Septic complications were three superficial and eight deep infections. Sufficient pain relief after arthrodesis was reported by 70 (63.6%) patients; in 37 (33.6%) patients the symptoms remained unchanged and 3 (2.7%) patients found their pain to be worse than before the procedure. Intramedullary compression nailing is shown to be an effective technique for tibiotalar arthrodesis in severe ankle arthropathy. The main advantages of the technique are limited soft tissue damage in the ankle area and high primary stability allowing early weight bearing.

[Intramedullary nailing in tibiotalocalcaneal arthrodesis]

Tibiotalcalcaneal arthrodesis is still the treatment of choice for disabling arthrosis of the upper and lower ankle joint, although replacement of the upper ankle joint is widely accepted. Numerous techniques have been described, with increasing use of internal fixation and compression. In 20 patients tibiotalocalcaneal arthrodesis was performed using a retrograde femur nail inserted through the heel, whereas in 20 patients combined arthrodesis of the upper and lower ankle joint was performed using a distal tibia nail through an anterograde approach. Patients were evaluated in a standardized examination using criteria of SF 36 focussing on approach, osseous consolidation, and quality of life.Both techniques demonstrated good results: bony consolidation was achieved after follow-up time of 19 months in 85% of the anterograde group and 95% of the retrograde group. In 78% pain was reduced effectively using the intramedullary nail arthrodesis and quality of life improved drastically. In four cases pseudarthrosis occurred, two implant failures were reported, and there were two infections. Using the anterograde as well as the plantar approach, tibiotalocalcaneal intramedullary nail arthrodesis is an appropriate technique. In this study both groups demonstrated good results regarding bony consolidation, reduction of pain, and improved quality of life. Advantage of the retrograde technique is the noninvasiveness of the proximal tibia. Heel pain or plantar infections were not observed. We see limits of the presented technique in severe malalignment and septic history of the patient.

[Psoas abscess after anterior spinal fusion]

We present 3 cases of secondary psoas abscess after anterior spinal fusion. Psoas abscess is still a rare clinical entity. It is often associated with unspecific symptomatology and may present as late infection. A high index of suspicion is required for early diagnosis and treatment. Computed tomography is the imaging technology of choice. Treatment includes open abscess drainage and antibiotic therapy. In secondary psoas abscess causative treatment of the primary infection focus is essential. For psoas abscess after anterior spondylodesis this includes treatment of a deep wound infection. Predisposing factors for postoperative infection are large implants, bone grafting, long operating times, previous spinal surgery, immunodeficiency and metabolic disorders. Usually several operations are necessary to eradicate infection. As long as stability is guaranteed, implant materials should be removed. Continuing antibiotic therapy for 2-3 weeks after normalization of infectious parameters is suggested. Delayed therapy results in an increase of the morbidity and mortality of psoas abscess.