Correlation Between Conditional Approval and Customized Bone Implant Devices.

This report aims to summarize key concerns regarding customized devices and conditional approval during the premarket evaluation of bone implants, and to explore the correlation between them. Based on the experience of approval of the first domestic custom-designed bone implant, we consider the process of gaining conditional approval for urgently-needed medical devices and medical devices for rare diseases, as well as the guidance available for clinical investigation. We also streamlined the scientifically administrative concept of this unique device, from the design and development of premarket technical evaluation to continuous post-market study. The present study found that those two aspects have certain connections, but they are not directly correlated to each other. In contrast to the USA, Canada, Australia and the EU, where regulations and guidelines have been established for the use of customized devices, in this regard, China is still it its infancy. Thus, there is considerable potential for China to develop and perfect the policies relating to customized devices and to develop relevant strategies to ensure their efficacy with the aid of conditional approval. Appropriate scientific conditional approval for mass production of individualized anatomy-matching bone implants could become a valuable approach for precision medicine.

Lower Extremity Abnormalities in Children.

Leg and foot problems in childhood are common causes of parental concern. Rotational problems include intoeing and out-toeing. Intoeing is most common in infants and young children. Intoeing is caused by metatarsus adductus, internal tibial torsion, and femoral anteversion. Out-toeing is less common than intoeing and occurs more often in older children. Out-toeing is caused by external tibial torsion and femoral retroversion. Angular problems include genu varum (bowleg) and genu valgum (knock knee). With pes planus (flatfoot), the arch of the foot is usually flexible rather than rigid. A history and physical examination that include torsional profile tests and angular measurements are usually sufficient to evaluate patients with lower extremity abnormalities. Most children who present with lower extremity problems have normal rotational and angular findings (i.e., within two standard deviations of the mean). Lower extremity abnormalities that are within normal measurements resolve spontaneously as the child grows. Radiologic studies are not routinely required, except to exclude pathologic conditions. Orthotics are not beneficial. Orthopedic referral is often not necessary. Rarely, surgery is required in patients older than eight years who have severe deformities that cause dysfunction.

A pedicle screw system and a lamina hook system provide similar primary and long-term stability: a biomechanical in vitro study with quasi-static and dynamic loading conditions.

PURPOSE: For the stabilization of the thoracolumbar spine area, various stabilization techniques have been developed in recent decades. The aim of these techniques is to immobilize the treated segment to repositioning or correct the spine and guaranty long-term stability to achieve a reliable fusion. The aim of this study was to simulate in an in vitro experiment the postoperative long-term situation in elderly osteoporotic patients to compare two different stabilization principles; a pedicle screw system and a lamina hook system. METHODS: Two comparable groups with respect to age and bone mineral density with each n = 6 fresh-frozen human, bi-segmental thoracolumbar spine specimens (T11-L1) were used. Antero-posterior and lateral radiographs were taken before the test, to assess the spinal status. Then the intact specimens were biomechanically characterized with pure moments in the three anatomical planes in different states in terms of range of motion and neutral zone. After implantation of either, a pedicle screw system or a lamina hook system, the primary stability was determined under the same conditions. Subsequently the specimens were cyclically loaded under complex loading, using a custom-made set-up in a dynamic materials testing machine with increasing moments from 3 to 66 Nm until 100,000 cycles or until one of the three defined "failure" criteria was reached. (1) A failure of a bony structure. (2) Exceeding of the threefold ROM of the primary stability after implantation in flexion plus extension. (3) Reaching of the ROM based on the intact state before implantation both in flexion plus extension. RESULTS: The results showed that the ROM was strongly reduced after instrumentation similar for both implant systems in all motion planes. The highest stabilization was found in flexion/extension. During cyclic loading with increasing moments, the ROM increased continuously for both systems. The number of load cycles until one of the failure criteria was reached varied only slightly between the two groups. In the pedicle screw group 30,000 (median) loading cycles (range 5000-80,000) with a corresponding moment of 24 Nm (range 9-54) could be reached. In the lamina hook group 32,500 load cycles (range 20,000-45,000) could be achieved with a corresponding moment of 25.5 Nm (range 18-33). There was a slight trend that the pedicle screw system is influenced more by bone mineral density. CONCLUSION: Both implant systems provide similar primary stability and similar long-term stability. In the pedicle screw group, there was a stronger correlation between bone mineral density and the reached number of load cycles.

[EXOTHERMIC REACTIONS OF PLASTER IMMOBILIZATION ­ ANALYSIS OF THREE KINDS OF PLASTER BANDAGES].

Exothermic reaction of plaster is a very important characteristic to understand, especially when it comes to complications which can occur during local temperature change during molding plaster of Paris. And these complications directly influence the speed and quality of treatment. In this paper we measured temperatures of plaster bandage tiles 10×10 cm, from three different manufacturers in Croatian hospitals: Safix plus (Hartmann, Germany), Cellona (Lohmann &Rauscher, Austria) and Gipsan ( Ivo Lola Ribar, Croatia). We made three different plaster tiles 10×10 cm, from 10, 15 and 30 layers of plaster bandages. We immersed plaster tiles in two different water temperatures, one group in water 22 °C, and another in 34 °C. Although all plaster bandages have similar chemical characteristics, we have measured some differences. All three kinds of plaster bandages used in Croatia have low exothermic reaction when plaster molding is done in standard conditions, average local temperature is low and there is no danger of local burns. We immersed a plaster tile with 15 layers in water on 34° C, and highest average temperature was measured at Gipsan (46.2 °C), then Cellona (41.3 °C) and Safix plus (38.9 °C). On the same water immersion temperature, on plaster tile with 30 layers average temperatures were Gipsan (48.4°C), Cellona (45.4 °C), and lowest in Safix plus (41.3 °C). Plaster tiles form all manufacturers, when used 15-30 layers thick, and water immersion temperature is 34°C, develop average temperature over 40°C, in duration from 8-12 minutes. Between three different plaster bandages analyzed, Gipsan (Ivo Lola Ribar, Croatia) developed highest temperature, and some plaster tiles were measured over 50 °C.

[About the treatment of battlefield injuries of the musculoskeletal system with the help of new "Rod field package"].

Injuries of the musculoskeletal system are at 60% of all battlefield injures and take first place in modern military conflicts. The main antishock measures are: pain management, emergency bleeding control, bone fragment positioning and fracture fixation. Specialist of the centre of traumatology and orthopaedics of the Burdenko General Military Clinical Hospital in cooperation with specialists of department of battlefield surgery of Mandryka Clinical Research and Training Medical Centre analysed the most effective domestic and foreign external fixators and developed Rod field package (RFP). The above mentioned researched had two stages. On the first (analytical) stage specialists formulated requirements for idea rod field external fixator. On the second (experimental) stage tests with the help of plastic models of long bones were carried out. The performed analysis showed, that installation of the external fixator is easy and fast, the external fixator is light and has capabilities for 3D bone fragment positioning and fracture fixation, the external fixator is radiotransparent. Implementation of this package into the clinical practice of delivery of battlefield emergency surgical care may improve results of treatment.

[Investigation of mechanical properties of materials used for functional stabilization in pilon fractures].

Existing methods of surgical treatment of the pilon fractures do not provide early functional rehabilitation of patients. The lack of confidence in secure fixation of fragments in significant quantity of patients causes necessity to apply a plaster immobilization during long time. While seeking possibilities of early functional treatment of the pilon fractures there was proposed a theory of "functional stabilization" (instead of "artificial", but necessary plaster immobilization), materials and technologies for its realization. For substantiating, from the biomechanical point of view, of expediency of a new materials (Softcost, Scotchcost) application the data about their physic-chemical properties were adduced, and in particular, there were studied the bowing values, depending on loading, and modules of elasticity of these materials.

The rationale for short uncemented stems in total hip arthroplasty.

Uncemented femoral implants of various designs have proved to provide stable initial and long-term fixation in patients who undergo total hip arthroplasty. Challenges in primary total hip arthroplasty have led to the evolution of short stem designs. These challenges include proximal/metaphyseal and distal/diaphyseal mismatch; facilitation of less-invasive surgical exposures, especially the direct anterior approach; and bone preservation for potential revision surgery.

[Clinical trials investigating the therapeutic benefit of medical devices in orthopaedics and trauma surgery: practice examples plus commentary]. / Studien zum therapeutischen Nutzen von Medizinprodukten in O+U: Kommentierte Praxisbeispiele.

Patients recognise relevant symptoms of the two leading diseases in orthopaedics and trauma surgery: osteoarthritis and fractures. Treatment effects can be demonstrated by patient reported outcomes. Total hip arthroplasty as an example for standard treatment regimen achieves large treatment effects. It is hard to demonstrate an additional benefit against standard treatment while observing ceiling effects. Alternative instruments are needed. Navigated total knee arthroplasty is done for better control of the postoperative axis as well as to reduce the revision burden. The time interval needed to demonstrate the decrease in revision has not yet passed. Additional benefits of total knee navigation have been observed for certain patient populations and for the training of physicians. These benefits have not been investigated so far. Using registries, expert opinions and case series the desired benefit from the use of medical devices can be shown. Safety is one major aspect of innovative medical devices as an additional benefit. The safety paradigm needs intense investigation in the future. The IDEAL Statement provides the clinical researcher with the methodological framework. The METEOR Statement focused on the medical problem and the possible benefit with using innovative medical devices. Within these recommendations a broad number of study types can be employed to demonstrate the benefits for patients.

[The choice of the treatment and surgical intervention for patients with fractures and dislocation fractures of front and middle parts of the foot].

For the period from 2004 till 2009 142 patients were observed in our clinic. We were able to follow up 53 of the 74 patients in the main group and 49 of the 68 ones in the control group for 12 months. The majority of injuries were located in the front area of foot; most of them were dislocation fractures. It was shown that the frequency of isolated stable and unstable traumas was roughly equal. Multiple injuries were generally unstable. We designed a simple convenient classification of fractures and dislocation fractures in front and middle parts of the foot. An original algorithm is proposed for the treatment and choice of operating methods based on our classification and ensuring satisfactory results in the majority of cases. Relief incisions outside projection of the surgical intervention field make it possible to close the operating wounds and avoid extension of their edges, prevent enlargement of edema, and avoid severe pyoinfectious complications in the early postoperative period. Overall, we achieved reduction of their frequency to 1% compared with 10% in the control group. The frequency of late complications was 9.44% versus 42.85% in controls.

The 1:1 versus the 2:2 tunnel-drilling technique: optimization of fixation strength and stiffness in an all-inside double-bundle anterior cruciate ligament reconstruction--a biomechanical study.

BACKGROUND: Double-bundle anterior cruciate ligament (ACL) reconstructions involve drilling 2 tibial tunnels separated by a narrow 2-mm bone bridge. The sequence of reaming and drilling the tibial tunnels for double-bundle ACL reconstructions has not been defined. HYPOTHESIS: Fixing a graft in the posterolateral ACL tibial tunnel before reaming the anteromedial tibial tunnel will reduce the number of complications, as compared with drilling both the anteromedial and posterolateral tunnels before graft fixation, when performing double-bundle ACL reconstructions. STUDY DESIGN: Controlled laboratory study. METHODS: Twelve porcine tibias were divided into 2 groups of 6 specimens. Fresh bovine extensor tendons grafts were fixed in 7-mm tunnels reamed using an inside-out method. Grafts were fixed in a retrograde fashion with 7-mm bioabsorbable retrograde screws. The tibias in group 1 were reconstructed by reaming and reconstructing the posterolateral tunnel before reaming and securing the graft for the anteromedial tunnel (ie, 1:1 method), whereas those in the second group were reconstructed by reaming both tunnels before graft fixation in either (ie, the 2:2 method). The specimens were biomechanically tested with cyclic and load-to-failure parameters. RESULTS: Cyclic testing revealed no significant difference between the 2 methods in displacement or stiffness. In load-to-failure testing, the 1:1 group withstood significantly higher initial failure loads and ultimate loads. Pullout displacement was significantly higher for the 1:1 group. Whereas no tibias in the 1:1 group sustained fractures, 4 from the 2:2 group demonstrated a bone bridge fracture. CONCLUSION: Soft tissue ACL grafts fixed in the tibia with the 1:1 method withstood significantly higher initial and ultimate failure loads and were stiffer than the grafts fixed with the 2:2 method. Tibias fixed with the 1:1 method were also less susceptible to bone bridge fracture. CLINICAL RELEVANCE: The potential for a lower complication rate and greater pullout strength seen with the 1:1 method may prove useful to surgeons performing anatomic double-bundle ACL reconstructions, in addition to other procedures involving reconstructing 2 closely positioned tunnels, including anatomic posterolateral corner and medial collateral reconstructions.

Osteotomies around the knee: patient selection, stability of fixation and bone healing in high tibial osteotomies.

New developments in osteotomy techniques and methods of fixation have caused a revival of interest of osteotomies around the knee. The current consensus on the indications, patient selection and the factors influencing the outcome after high tibial osteotomy is presented. This paper highlights recent research aimed at joint pressure redistribution, fixation stability and bone healing that has led to improved surgical techniques and a decrease of post-operative time to full weight-bearing.

Change of cervical balance following single to multi-level interbody fusion with cage.

Postoperative limitation of cervical movement and adjacent disc degeneration are major causes of postoperative neck pain after anterior cervical discectomy and interbody fusion (ACDF). We present a retrospective study of dynamic radiographic change following ACDF with cages. We performed ACDF in 50 patients with cervical degenerative diseases, divided into three groups based on the level of interbody fusion (Group A: one-level; Group B: two-level; Group C: three-level). Preoperative and postoperative flexion-extension X-rays were acquired and cervical range of motion (ROM), lordosis, fusion rate, cage subsidence rate, postoperative neck pain as evaluated by visual analogue scale (VAS) and upper adjacent level segmental movement were evaluated. The average following time was 14.6 months. The mean change in lordotic curve was -2.31 +/- 9.53 degrees for Group A, 5.60 +/- 6.96 degrees for Group B, and 3.23 +/- 7.50 degrees for Group C (p value = 0.03). The mean change in flexion angle was -5.46 +/- 8.69 degrees for Group A, -10.2 +/- 7.38 degrees for Group B, and -13.86 +/- 10.33 degrees for Group C (p value = 0.039). The mean change in total cervical ROM was -3.85 +/- 18.74 degrees for Group A, -12.73 +/- 10.31 degrees for Group B, and -16.95 +/- 10.57 degrees for Group C (p value = 0.02). Follow-up cervical MRI for patients with persistent neck pain showed no evidence of adjacent level degeneration. There were no significant differences between the three groups with respect to postoperative change in cervical extension angle, upper adjacent level segmental movement, neck pain VAS, fusion rate or cage subsidence rate. The further decrease in total cervical ROM and flexion movement after multi-level ACDF was observed. However, a more long-term follow-up was needed to assess the actual aetiologies of upper adjacent level degeneration.

Segmental spinal instrumentation in the management of scoliosis.

Spinal instrumentation for the correction of spinal deformity began with Harrington and his rod system. The use of the Harrington rods was limited, however, because of the need for long-segment instrumentation, distraction, and the potential for hood dislodgment and construct failure. Luque subsequently introduced the next generation of spinal fixation techniques via the concept of segmental instrumentation; his use of sublaminar wires allowed the construct to be fixated to the spine at every level. This arrangement allowed greater control over correction of spinal deformities and significantly lessened the incidence of hardware dislodgment. Modern instrumentation systems, including the use of pedicle screws, permit even greater control of the spine in multiple planes during deformity correction. Newer strategies have decreased the incidence of neurological injury during implant application and provide greater stability. A review of segmental fixation, including surgical techniques, is provided in this article.

Correction of tibial deformity in Paget's disease using the Taylor spatial frame.

A 64-year-old man presented with a severe deformity of the tibia caused by Paget's disease and osteoarthritis of the ipsilateral knee. Total knee replacement required preliminary correction of the tibial deformity. This was successfully achieved by tibial osteotomy followed by distraction osteogenesis using the Taylor spatial frame. The subsequent knee replacement was successful, with no recurrence of deformity.

Stress corrosion cracking of an aluminum alloy used in external fixation devices.

Treatment for compound and/or comminuted fractures is frequently accomplished via external fixation. To achieve stability, the compositions of external fixators generally include aluminum alloy components due to their high strength-to-weight ratios. These alloys are particularly susceptible to corrosion in chloride environments. There have been several clinical cases of fixator failure in which corrosion was cited as a potential mechanism. The aim of this study was to evaluate the effects of physiological environments on the corrosion susceptibility of aluminum 7075-T6, since it is used in orthopedic external fixation devices. Electrochemical corrosion curves and alternate immersion stress corrosion cracking tests indicated aluminum 7075-T6 is susceptible to corrosive attack when placed in physiological environments. Pit initiated stress corrosion cracking was the primary form of alloy corrosion, and subsequent fracture, in this study. Anodization of the alloy provided a protective layer, but also caused a decrease in passivity ranges. These data suggest that once the anodization layer is disrupted, accelerated corrosion processes occur.

Prevalence of long-bone non-unions.

Despite the enormous progress made during recent decades in the treatment of long-bone fractures, fracture healing is still haunted by complications and above all non-unions. Non-unions represent a particular challenge, and the difficulties surrounding their management are frequently underestimated. Knowledge of the epidemiology of long-bone non-union can assist the treating surgeon in the application of the optimum fracture treatment.