Complications during removal of conventional versus locked compression plates: is there a difference?

BACKGROUND: Osteosynthesis plate removal is one of the most commonly performed procedures in orthopaedic surgery. Due to technological advances and the quality of increasing osteosynthesis material, more and more locked plates have been implanted over the last 20 years. The aim of this study was to determine whether the complication rate during plate removal differs between conventional and locked plates. MATERIAL AND METHODS: In this retrospective cohort study, 620 patients were included and divided into two groups based on the type of plate (locked and conventional). Technical complications during implant removal included screw breakage, destroyed screw head, implant breakage, remaining implant material, refracture, bony or soft tissue overgrowth. The following plate-associated complications were identified: osteosynthesis plate not detachable, plate bent or broken, necessity of special tools or plate loosened. Three types of screw-related complications were observed: screw not detachable, screw broken or screw dislocated. RESULTS: Overall, complications related to the plate or screws were documented in 110 of the 620 cases. These complications occurred in 48 of the 382 cases involving conventional osteosynthesis (7.7% of all removals, 12.6% of all conventional removals) and in 62 of the 238 cases involving locked plate osteosynthesis (10.0% of all removals, 26.1% of all locked plate removals). The statistical analysis showed a significantly higher implant-related complication rate with locked plates compared to the conventional plates (p < 0.01). CONCLUSIONS: Hardware removal can be a complication-afflicted operation, especially cases involving locked-plate removal should only be performed if a strong indication is evident. Possible benefits of the procedure should be considered carefully, taking the cost-benefit ratio into account.

Biomechanical evaluation of novel ultrasound-activated bioresorbable pins for the treatment of osteochondral fractures compared to established methods.

BACKGROUND: Osteochondral injuries often lead to osteoarthritis of the affected joint. All established systems for refixation of osteochondral defects show certain disadvantages. To address the problem of reduced stability in resorbable implants, ultrasound-activated pins were developed. By ultrasound-activated melting of the tip of these implants, a more secure anchoring is assumed. MATERIALS AND METHODS: The aim of the study was to investigate if ultrasound-activated pins can provide secure fixation of osteochondral fragments compared to screws and conventional resorbable pins. In a biomechanical laboratory setting, osteochondral fragments of the medial femoral condyle of sheep were refixated with ultrasound-activated pins [US fused poly(L-lactide-co-D,L-lactide) (PLDLLA) pins], polydioxanone (PDA) pins and conventional titanium screws. Anchoring forces of the different fixation methods were examined, registered and compared concerning shear force and tensile force. RESULTS: Concerning the pull out test, the US fused PLDLLA pins and titanium screws (~122 N and ~203 N) showed comparable good results, while the PDA pins showed significantly lower anchoring forces (~18 N). Examination of shear forces showed a significantly higher anchoring of the screws (~248 N) than the US fused PLDLLA pins (~218 N). Nevertheless, the US fused PLDLLA pins could significantly outperform the PDA pins (~68 N) concerning shear forces. CONCLUSION: The US fused PLDLLA pins demonstrated a comparable anchorage to the fixation with screws, but were free from the disadvantages of metal implants, i.e. the need for implant removal. The PDA pin application showed inferior biomechanical properties.

Accuracy of a hexapod parallel robot kinematics based external fixator.

BACKGROUND: Different hexapod-based external fixators are increasingly used to treat bone deformities and fractures. Accuracy has not been measured sufficiently for all models. METHODS: An infrared tracking system was applied to measure positioning maneuvers with a motorized Precision Hexapod® fixator, detecting three-dimensional positions of reflective balls mounted in an L-arrangement on the fixator, simulating bone directions. By omitting one dimension of the coordinates, projections were simulated as if measured on standard radiographs. Accuracy was calculated as the absolute difference between targeted and measured positioning values. RESULTS: In 149 positioning maneuvers, the median values for positioning accuracy of translations and rotations (torsions/angulations) were below 0.3 mm and 0.2° with quartiles ranging from -0.5 mm to 0.5 mm and -1.0° to 0.9°, respectively. CONCLUSIONS: The experimental setup was found to be precise and reliable. It can be applied to compare different hexapod-based fixators. Accuracy of the investigated hexapod system was high.

Decision-making in the treatment of diaphyseal clavicle fractures: is there agreement among surgeons? Results of a survey on surgeons' treatment preferences.

BACKGROUND AND HYPOTHESIS: Nonoperative treatment is standard for most diaphyseal clavicle fractures, but recent studies have demonstrated improved outcomes with operative treatment of displaced fractures. The objectives of this diagnostic study were to assess agreement of orthopaedic surgeons regarding their treatment preferences for diaphyseal clavicle fractures and to compare them with recent recommendations. Interobserver and intraobserver agreement in treatment decisions were hypothesized to be only slight. METHODS: Anonymized case vignettes of 50 acute diaphyseal clavicle fractures including medical history, physical examination findings, and radiographs were independently reviewed by 32 orthopaedic surgeons from the United States. Four treatment options were offered and decisions were compared with current treatment recommendations. Interobserver agreement was calculated using Fleiss' kappa coefficient. Average intraobserver agreement for surgeons who completed a retest review (minimum interval of 8 weeks) was calculated. RESULTS: Thirty-two surgeons completed the first round of reviewing and 27 completed the retest (mean interval, 22 weeks). Interobserver agreement was overall fair (kappa = 0.36) and moderate (kappa = 0.56) when operative options were compared with nonoperative options. Median intraobserver agreement was 74% for the 4 treatment options offered and 84% in deciding on operative vs. nonoperative means. Concordance with recent recommendations for operative vs. nonoperative treatment was seen in 91% of decisions (median). DISCUSSION AND CONCLUSIONS: Recent recommendations appear to have been adopted by a selected subgroup of U.S. orthopaedic surgeons, showing a surprisingly high median concordance of 91% in this study. However, only fair to moderate interobserver and intraobserver agreement was present, leaving potential for improvement.