Treatment of both simple and complex patella fractures is a challenging clinical problem. The aim of this study was to investigate the biomechanical performance of recently developed lateral rim variable angle locking plates versus tension band wiring used for fixation of simple and complex patella fractures.

Twelve pairs of human anatomical knees were used to simulate either two-part transverse simple AO/OTA 34C1 or five-part complex AO/OTA 34C3 patella fractures by means of osteotomies, with each fracture model created in six pairs. The complex fracture pattern was characterized by a medial and a lateral proximal fragment, together with an inferomedial, an inferolateral, and an inferior fragment mimicking comminution around the distal patellar pole. The specimens with simple fractures were pairwise assigned for fixation with either tension band wiring through two parallel cannulated screws, or a lateral rim variable angle locking plate. The knees with complex fractures were pairwise treated with either tension band wiring through two parallel cannulated screws plus circumferential cerclage wiring, or a lateral rim variable angle locking plate.

Each specimen was tested over 5000 cycles by pulling on the quadriceps tendon, simulating active knee extension and passive knee flexion within the range of 90° flexion to full knee extension. Interfragmentary movements were captured via motion tracking.

For both fracture types, the longitudinal and shear articular displacements measured between the proximal and distal fragments at the central patella aspect between 1000 and 5000 cycles, together with the relative rotations of these fragments around the mediolateral axis were all significantly smaller following the lateral rim variable angle locked plating compared with tension band wiring, p<0.01.

Lateral rim locked plating of both simple and complex patella fractures provides superior construct stability versus tension band wiring under dynamic loading.

Treatment of simple and complex patella fractures represents a challenging clinical problem. Controversy exists regarding the most appropriate fixation method. Tension band wiring, aiming to convert the pulling forces on the anterior aspect of the patella into compression forces across the fracture site, is the standard of care, however, it is associated with high complication rates. Recently, anterior variable-angle locking plates have been developed for treatment of simple and comminuted patella fractures. The aim of this study was to investigate the biomechanical performance of the novel anterior variable-angle locking plates versus tension band wiring used for fixation of simple and complex patella fractures.

Sixteen pairs of human cadaveric knees were used to simulate either two-part transverse simple AO/OTA 34-C1 or five-part complex AO/OTA 34-C3 patella fractures by means of osteotomies, with each fracture model created in eight pairs. The complex fracture pattern was characterized with a medial and a lateral proximal fragment, together with an inferomedial, an inferolateral and an inferior fragment mimicking comminution around the distal patellar pole. The specimens with simple fractures were pairwise assigned for fixation with either tension band wiring through two parallel cannulated screws, or an anterior variable-angle locking core plate. The knees with complex fractures were pairwise treated with either tension band wiring through two parallel cannulated screws plus circumferential cerclage wiring, or an anterior variable-angle locking three-hole plate. Each specimen was tested over 5000 cycles by pulling on the quadriceps tendon, simulating active knee extension and passive knee flexion within the range from 90° flexion to full knee extension. Interfragmentary movements were captured by motion tracking.

For both fracture types, the articular displacements, measured between the proximal and distal fragments at the central aspect of the patella between 1000 and 5000 cycles, together with the relative rotations of these fragments around the mediolateral axis were all significantly smaller following the anterior variable-angle locked plating compared with the tension band wiring, p < 0.01

From a biomechanical perspective, anterior locked plating of both simple and complex patella fractures provides superior construct stability versus tension band wiring.

Three Cannulated Screws (3CS), Dynamic Hip Screw (DHS) with antirotation screw (DHS–Screw) or with a Blade (DHS–Blade) are the gold standards for fixation of unstable femoral neck fractures. Compared to 3CS, both DHS systems require larger skin incision with more extensive soft tissue dissection while providing the benefit of superior stability. The newly designed Femoral Neck System (FNS) for dynamic fixation combines the advantages of angular stability with a less invasive surgical technique. The aim of this study is to evaluate the biomechanical performance of FNS in comparison to established methods for fixation of the femoral neck in a human cadaveric model.

Twenty pairs of fresh–frozen human cadaveric femora were instrumented with either DHS–Screw, DHS–Blade, 3CS or FNS. A reduced unstable femoral neck fracture 70° Pauwels III, AO/OTA31–B2.3 was simulated with 30° distal and 15° posterior wedges. Cyclic axial loading was applied in 16° adduction, starting at 500N and with progressive peak force increase of 0.1N/cycle until construct failure. Relative interfragmentary movements were evaluated with motion tracking.

Highest axial stiffness was observed for FNS (748.9 ± 66.8 N/mm), followed by DHS–Screw (688.8 ± 44.2 N/mm), DHS–Blade (629.1 ± 31.4 N/mm) and 3CS (584.1 ± 47.2 N/mm) with no statistical significances between the implant constructs. Cycles until 15 mm leg shortening were comparable for DHS–Screw (20542 ± 2488), DHS–Blade (19161 ± 1264) and FNS (17372 ± 947), and significantly higher than 3CS (7293 ± 850), p<0.001. Similarly, cycles until 15 mm femoral neck shortening were comparable between DHS–Screw (20846 ± 2446), DHS–Blade (18974 ± 1344) and FNS (18171 ± 818), and significantly higher than 3CS (8039 ± 838), p<0.001.

From a biomechanical point of view, the Femoral Neck System is a valid alternative to treat unstable femoral neck fractures, representing the advantages of a minimal invasive angle–stable implant for dynamic fixation with comparable stability to the two DHS systems with blade or screw, and superior to Three Cannulated Screws.

Introduction: Primary operative stabilisation of Grade III injuries of the acromio-clavicular (AC) joint remains controversial, with recent literature providing support for conservative management. The aim of this research was to compare the clinical and radiological outcome of operative and non-operative treatment of this injury.

Materials and Methods: 56 patients (51 men, 5 women, aged 18 – 78 years) with an acromio-clavicular dislocation Tossy III were recruited into the study. 28 were managed surgically with a hook plate, and 28 were treated non-operatively with a sling until they were pain-free after a few days. The mean follow-up time was 23 months (8 – 31 months). At follow-up the patients were either examined clinically and radiologically or they were surveyed by phone. Clinical results were expressed in the Constant score and the subjective satisfaction of each patient was recorded.

Results: Eleven patients were lost to follow-up. Five patients were operated at their home hospital after initial treatment at our clinic, and four non-surgical patients were later treated with a modified Weaver-Dunn procedure.

Of the remaining 36 patients, 25 were examined clinically and radiologically and 11 were surveyed by telephone. The clinical outcome showed a mean Constant score of 87 in the operative group and 96 in the non-operative group. 30 of 36 patients were highly satisfied or satisfied (19 in the operative group, 11 in the non-operative group), 5 were mostly satisfied (operative group), 1 was unsatisfied (operative group). Radiologically, all of the operated patients showed changes of the AC-joint including widening of the joint, redislocation of the distal clavicle, and degenerative changes. In the non-operative group, three patients showed a decreasing clavicular elevation.

Conclusion: Clinical outcomes were comparable between operative and non-operative treatment of AC-dislocations grade III. Some conservatively treated patients did, however, require a secondary stabilisation. The hook plate was observed to cause additional local injury to the AC-joint, and must be removed after recovery to prevent rotator cuff damage. This procedure incurs high risk of loss of reduction. In our opinion, it is disputable to operate twice on the AC-joint to achieve similar results as those obtained with conservative treatment. We prefer a secondary anatomical reconstruction in cases of failed conservative treatment.

OBJECTIVES: In recent years the incidence of proximal humerus fractures increased strongly. The optimal treatment of displaced, unstable fractures is still controversial. One of the major problem seen in previous treatment options was implant failure with secondary dislocation, pseudarthrosis and AVN. New angular stable implants promise a stronger anchorage and allow early functional aftertreatment, especially in osteopenic bone. Aim of this prospective case-series was to assess complication risks and functional outcome after ORIF with an angular stable form plate

DESIGN: Prospective case-series

SETTING: Multicenter study in 8 European Trauma Units

PATIENTS: 157 patients were treated for 158 displaced proximal humerus fractures

INTERVENTION: ORIF with a PHILOS^™ plate.

RESULTS: According to the AO/ASIF classification 25%, 61% and 37% were classified as type A, B and C, respectively. One year follow-up rate was 84%, whereupon 6 patients had died in the mean time and 18 were lost to follow-up. Overall 71 complications were observed in 53 patients and led to 39 unplanned re-operations, whereupon most frequent were primary screw perforations (n=22), secondary screw perforations (n=13)–mostly with secondary impaction (n=11), and AVN (n=8). Increasing age and severity of fractures influenced the occurrence of complications, since the risk to obtain a complication was doubled in patients over 60 years compared to younger (Relative Risk 1.9; Fischer’s Exact, p=0.022) as well as in AO/ASIF B- and C-fractures compared to A-fractures (Relative Risk=1.8; Fischer’s Exact, p=0.05). Risks for complications related to the implant, surgical technique or fracture and bone were 9%, 20% and 13%, respectively. Within one year all fractures healed and 5 secondary dislocations were observed. The mean (SD) Constant score of the injured shoulder improved during follow-up period to 72 points (15.2) at 12 months follow-up, when 87% (16.6%) of the contralateral shoulder was reached. Across all follow-up examinations the Constant score in relation to the contralateral shoulder impaired with increasing severity of the fracture (ANOVA, p=0.006). The mean (SD) DASH score after one year was with 16 points (21.1) worser (T-test, p< 0.001) than before the accident [5.2 (11.4)].

CONCLUSIONS: Fixation with a Philos plate provides high stability to preserve achieved reduction, which benefits the good functional outcome. However surgical technique related complication risks are high, particularly due to screw perforations into the joint. Augmented awareness and improvement of surgical technique should reduce these risks. Complex fracture types and higher age increases the risk to sustain complications, where as only severity of fractures impairs the functional outcome.