Improving fixation of the osteoporotic fracture: the role of locked plating

Fixation Principles for Pathologic Fractures in Metasatic Disease

The management of pathologic fractures differs from nonpathologic fractures with respect to preoperative evaluation, surgical strategies, adjuvant therapies, and complication rates. These issues must be understood to provide appropriate musculoskeletal care for patients with metastatic disease.

Enhancement of local bone formation on titanium implants in osteoporotic rats by biomimetic multilayered structures containing parathyroid hormone (PTH)-related protein

Osteoporosis is a severe health problem causing bone fragility and consequent fracture. Titanium (Ti) implants, used in patients with osteoporotic fractures, are prone to failure because of the decreased bone mass and strength. Therefore, it is of utmost importance to fabricate implants possessing osteogenic properties to improve implant osseointegration. To improve the long-term survival rate of Ti implants in osteoporotic patients, hyaluronic acid/ϵ-polylysine multilayers containing the parathyroid hormone (PTH)-related protein (PTHrP) were deposited on Ti implants by a layer-by-layer (LBL) electro assembly technique. The murine pre-osteoblast cell line MC3T3-E1, possessing a high potential of osteoblast differentiation, was used to evaluate the osteo-inductive effects of Ti-LBL-PTHrP in vitro. In addition, the performance of the Ti (Ti-LBL-PTHrP) implant was evaluated in vivo in a femoral intramedullary implantation in Sprague Dawley rats. The Ti-LBL-PTHrP implant regulated the release of the loaded PTHrP to increase bone formation in the early stage of implantation. The in vitro results revealed that cells on Ti-LBL-PTHrP did not show any evident proliferation, but a high level of alkaline phosphatase activity and osteoblast-related protein expression was found, compared to the uncoated Ti group (p < 0.05). In addition, in vivo micro-CT and histological analysis demonstrated that the Ti-LBL-PTHrP implants could significantly promote the formation and remodeling of new bone in osteoporotic rats at 14 d after implantation. Overall, this study established a profound and straightforward methodology for the manufacture of biofunctional Ti implants for the treatment of osteoporosis.

Treatment of proximal humerus fractures in geriatric patients - Can pathological DEXA results help to guide the indication for allograft augmentation?

INTRODUCTION

Reconstruction of proximal humerus fracture continues to represent a challenge, especially in severe osteopenia. However, there still is a lack of consensus and clear indication on use of allograft augmentation. Therefore, this study aims to investigate outcome after osteosynthesis with and without allograft augmentation. It focuses on bone density results obtained by DEXA as potential examination that might help decision-making.

METHODS

This study included patients aged 65 years and older that were treated at one Level 1 trauma center between 2007 and 2018. Inclusion criteria: Proximal humerus fracture treated with or without allograft, conclusive data-sets. Exclusion criteria: prior surgical treatment of the proximal humerus, open fracture with bone loss, neurological damage. Patients were stratified according to the use of allograft augmentation in two groups: Group NA (no allograft augmented PHILOS) and Group A (PHILOS with allograft augmentation). Comorbidity was assessed using the Charlson Comorbidity Index (CCI). Fractures were graded according to the classification by Neer. Radiographic union was analyzed at 6 weeks, 12 weeks, and at year follow up. Complications include surgical site infection, implant failure, humeral head necrosis, or delayed union. Allograft was used in cases of 1inch/3cm3 bone-loss or an egg-shell situation, where the patient refused arthroplasty.

RESULTS

This study included 167 patients, with 143 (85%) in the Group NA, and 24 (15%) in the Group A. There were no significant differences in age, gender, injury distribution, and distribution of Neer classification or CCI. Patients in Group A had significantly lower T-scores preoperatively (-2.87 ± 1.08 versus -0.9 ± 2.12, p = 0.003). No difference occurred in any of the complications. At one-year follow-up, the range of motion was comparable in both groups.

CONCLUSION

In patients with allograft augmentation and severe osteopenia, similar clinical and radiological results were obtained when compared with patients with better preoperative bone density scores (T-scores, DEXA). In view of a lack of guidelines indicating the indication for the use of allograft, this difference may be worth further study.

Intrinsic Fixation of the Tibial Sesamoid in First Metatarsophalangeal Joint Arthrodesis: A Cadaveric Study

Nonunion rate of first metatarsophalangeal joint (MTP) joint arthrodesis is reportedly less than 6%, regardless of fixation type. Robust modern plating constructs aim to decrease incidence of nonunion while also allowing early postoperative weight-bearing. Quicker transition to weight-bearing postoperatively increases patient adherence, decreases adjacent joint stiffness, and reduces risk of deep vein thrombosis in the postoperative period. The purpose of this study was to investigate the effect tibial sesamoid fixation has on first MTP joint arthrodesis.

Comparison of Less Invasive Stabilization System Plate and Retrograde Intramedullary Nail in the Fixation of Femoral Supracondylar Fractures in the Elderly: A Biomechanical Study

Objective

To compare the biomechanical stabilities of less invasive stabilization system (LISS) plate and retrograde intramedullary nail (IMN) for the comminuted femoral supracondylar fracture fractures in the elderly.

Methods

Sixteen pairs of embalmed cadaver femurs were obtained to simulate a comminuted supracondylar femur fracture (AO/OTA33‐A3) gap model. All left‐side specimens were fixed with LISS plate, and retrograde IMN were applied to the right‐side specimens. All specimens were tested in torsional, axial and cyclic load mode on an Instron testing machine.

Results

The mean torsional stiffness for LISS plate group was 34.1% greater than retrograde IMN group (2.90 vs. 1.91 Nm/degree, P = 0.002), but the mean axial stiffness was greater for the retrograde IMN (199.16 vs. 303.93 N/mm, P < 0.001). The total deformation of LISS plate caused by cyclic axial loading was greater than retrograde IMN (4.17 vs. 3.57 mm, P = 0.014). Significantly less mean irreversible deformation was detected in LISS plate than in retrograde IMN (1.64 vs. 1.69 mm, P = 0.699). Failure loads of the constructs were significantly different between the two groups (LISS plate: 2941±128 N; retrograde IMN: 4022±176 N, P < 0.001).

Conclusion

For comminuted femoral supracondylar fractures in the elderly, the tested instruments can both maintain sufficient biomechanical stabilities, but retrograde IMN is superior to LISS plate in deformation of fracture site.

Biomechanical comparison between standard and inclined screw orientation in dynamic hip screw side-plate fixation: The lift-off phenomenon

Background

Common failure modes of dynamic hip screw are cut-out and lift-off. To minimize the latter, distal screws can be inserted in different orientations. However, the effectiveness remains controversial. The aim of this study was to biomechanically investigate the influence of distal screw orientation on construct stability.

Methods

Thirty artificial generic long bones were assigned to three groups (n = 10) and fixed with two-hole dynamic hip screw–plates, inserting distal cortical screws with neutral parallel screw orientation (A), divergent screw orientation (B) or convergent screw orientation (C). Starting at 60 N, cyclic loading was applied to the implant tip perpendicular to the lag screw axis with progressive peak load increase at a rate of 0.002 N/cycle until failure. Parameters of interest were construct stiffness and machine actuator displacement after 250, 1000 and 5000 cycles, as well as cycles to failure.

Results

Displacement after 250, 1000 and 5000 cycles was significantly higher in Group C than in Groups A and B, p < 0.01, whereas no significant differences were observed between Groups A and B, p = 0.20. Specimens in Group C failed after 11,584 [standard deviation (SD), 5924] cycles, significantly earlier than those in Groups A and B [A: 27,351 (SD, 12,509); B: 28,793 (SD, 14,764)], p ≤ 0.02. Cycles to failure were not significantly different between Groups A and B, p > 0.99.

The translational potential of this article

Parallel or divergent distal screw insertion provides similar construct stability in terms of resistance to plate lift-off. In contrast, converging screw insertion leads to inferior stability and is not advisable from a biomechanical point of view.

Compression screws and buttress plate versus compression screws only for Hoffa fracture in Chinese patients: a comparative study

Objective

To compare compression screws and buttress plate (CS plus BP) with compression screws only (CS) in treating patients with Hoffa fracture.

Methods

This retrospective study included Chinese patients with Hoffa fracture treated by open reduction and internal fixation. Radiographs and clinical outcomes (range of movement [ROM], bone union and Knee Society Score [KSS]) were compared between patients treated using CS plus BP versus CS only.

Results

At 4 months following surgery, significantly better outcomes were shown in the CS plus BP group (n = 24) versus CS only group (n = 21) regarding ROM (120.4 ± 5.2° versus 110 ± 7.1°) and KSS (85.5 ± 4.1 versus 79.7 ± 3.3). At the 12-month follow-up, significantly better outcomes were maintained in the CS plus BP versus CS only group regarding ROM (126.2 ± 7.4° versus 120.5 ± 8.2°) and KSS (88.3 ± 4.6 versus 84.2 ± 4.0). At the final follow-up, all patients had normal fracture healing and no malunion, nonunion or reduction loss.

Conclusions

Fixation with CS plus BP for Hoffa fracture is effective and reliable, and may provide more adequate stability and better outcomes versus CS only.

Modulation of Osteoclast Interactions with Orthopaedic Biomaterials

Biomaterial integration in bone depends on bone remodelling at the bone-implant interface. Optimal balance of bone resorption by osteoclasts and bone deposition by osteoblasts is crucial for successful implantation, especially in orthopaedic surgery. Most studies examined osteoblast differentiation on biomaterials, yet few research has been conducted to explore the effect of different orthopaedic implants on osteoclast development. This review covers, in detail, the biology of osteoclasts, in vitro models of osteoclasts, and modulation of osteoclast activity by different implant surfaces, bio-ceramics, and polymers. Studies show that surface topography influence osteoclastogenesis. For instance, metal implants with rough surfaces enhanced osteoclast activity, while smooth surfaces resulted in poor osteoclast differentiation. In addition, surface modification of implants with anti-osteoporotic drug further decreased osteoclast activity. In bioceramics, osteoclast development depended on different chemical compositions. Strontium-incorporated bioceramics decreased osteoclast development, whereas higher concentrations of silica enhanced osteoclast activity. Differences between natural and synthetic polymers also modulated osteoclastogenesis. Physiochemical properties of implants affect osteoclast activity. Hence, understanding osteoclast biology and its response to the natural microarchitecture of bone are indispensable to design suitable implant interfaces and scaffolds, which will stimulate osteoclasts in ways similar to that of native bone.

A Short-Term Retrospective of First Metatarsophalangeal Joint Arthrodesis Using a Plate With PocketLock Fixation

BACKGROUND

Various techniques have been described for arthrodesis of the first metatarsophalangeal (MTP) joint. The purpose of this study was to retrospectively review the results of fixation for the first MTP arthrodesis of patients treated using dome-shaped reamers to prepare the joint surfaces and a novel MTP Plate with PocketLock fixation.

METHODS

Between July 2012 and November 2013, 16 feet in 16 patients were treated with a first MTP arthrodesis with a MTP Plate with PocketLock fixation. The mean patient age was 58.8 years (range, 46-82 years). Physical and radiographic examinations were performed at follow-up visits. The average follow-up period was 17.3 months. The radiographs were examined for union (3 bridging cortices), time to union, hardware failure, or other radiographic complications. The charts were reviewed to assess AOFAS-MTP-IP (American Orthopaedic Foot & Ankle Society metatarsophalangeal-interphalangeal) scores and postoperative complications.

RESULTS

Fusion was seen in 11 of 16 feet (68.8%) and partial union in 1 patient (6.3%). Five nonunions (31.2%) were noted in the sample group: All were symptomatic and required revision surgery. No malunions were identified in our sample. One hardware failure was documented in a nonunion patient. The mean time to osseous union was 81.7 ± 15.9 days. The preoperative AOFAS MTP-IP score was 55.6 and the postoperative score was 64.7.

CONCLUSION

The high nonunion and revision surgery rates demonstrate that this particular plate should be used with caution for a first MTP joint arthrodesis.

LEVEL OF EVIDENCE

Therapeutic, Level IV: Case series.

Local drug delivery for enhancing fracture healing in osteoporotic bone

Fragility fractures can cause significant morbidity and mortality in patients with osteoporosis and inflict a considerable medical and socioeconomic burden. Moreover, treatment of an osteoporotic fracture is challenging due to the decreased strength of the surrounding bone and suboptimal healing capacity, predisposing both to fixation failure and non-union. Whereas a systemic osteoporosis treatment acts slowly, local release of osteogenic agents in osteoporotic fracture would act rapidly to increase bone strength and quality, as well as to reduce the bone healing period and prevent development of a problematic non-union. The identification of agents with potential to stimulate bone formation and improve implant fixation strength in osteoporotic bone has raised hope for the fast augmentation of osteoporotic fractures. Stimulation of bone formation by local delivery of growth factors is an approach already in clinical use for the treatment of non-unions, and could be utilized for osteoporotic fractures as well. Small molecules have also gained ground as stable and inexpensive compounds to enhance bone formation and tackle osteoporosis. The aim of this paper is to present the state of the art on local drug delivery in osteoporotic fractures. Advantages, disadvantages and underlying molecular mechanisms of different active species for local bone healing in osteoporotic bone are discussed. This review also identifies promising new candidate molecules and innovative approaches for the local drug delivery in osteoporotic bone.

Comparative clinical study of locking screws versus smooth locking pegs in volar plating of distal radius fractures

The present study was performed to test the null hypothesis on no difference in stability of fixation after volar plating of intra-articular distal radius fractures (AO C2-C3) with either locking smooth pegs or locking screws in a clinical setting. A retrospective evaluation included adult patients with C2-C3 AO fractures treated with a volar plate with locking smooth pegs or locking screws. Radiographic assessment was performed to evaluate extra- and intra-articular parameters in the early postoperative period and after bone union. Twenty-seven consecutive patients were included. Thirteen cases had fixation with locking screws and 14 had fixation with locking smooth pegs. Both groups had bone fragment displacement after fixation. However, there were no significant differences between the groups either in extra- or intra-articular parameters defined by Kreder et al. (1996). Our study shows that, in a clinical setting, there is no difference in stability fixation between locking screws or smooth locking pegs in C2-C3 distal radius fractures.

Plate on plate osteosynthesis for the treatment of nonhealed periplate fractures

Purpose. The purpose of this paper is to present our technique for the treatment of periplate fractures. Methods. From 2009 to 2012 we treated three patients. In all cases the existing plate was left and the new one placed over the existing. Locking screws were placed through both plates. The other screws in the new plate were used as best suited the fracture. Results. In all cases less than 6 months had passed between fractures. None of the original fractures had healed. Mean followup was 2 years. All fractures proceeded to union within 7 months. No complications were recorded. All the patients returned to their normal activities and were satisfied with the results of their treatment. Conclusion. Our plate on plate technique is effective for the treatment of periplate fractures. A solid fusion can be achieved at the new fracture site without disturbing the previous fixation.

A Standardized Critical Size Defect Model in Normal and Osteoporotic Rats to Evaluate Bone Tissue Engineered Constructs

Tissue engineered constructs should be tested for their efficacy not only in normal but also in osteoporotic bone. The rat is an established animal model for osteoporosis and is used often for bone healing studies. In this study a defined and standardized critical size defect model in the rat suitable for screening new tissue engineered constructs in normal and osteoporotic bone is described and validated. Normal and ovariectomised Wistar rats received a unilateral middiaphyseal 5 mm defect in the femur, which was instrumented with a radiolucent PEEK plate fixed with angular stable titanium screws and left untreated. All animals were euthanized eight weeks after defect surgery and the bone healing was evaluated using radiographs, computed tomography measurements, and histology. The developed fixation system provided good stability, even in osteoporotic bone. The implants and ancillary instruments ensured consistent and facile placement of the PEEK plates. The untreated defects did not heal without intervention making the model a well-defined and standardized critical size defect model highly useful for evaluating tissue engineered solutions in normal and osteoporotic bone.

Management of high-energy foot and ankle injuries in the geriatric population

By the year 2035 almost 20% of the US population of 389 million people will be 65 years and older. What this group has, compared with aged populations in the past, is better health, more mobility, and more active lifestyles. From January 1989 through December 2010, a total of 494 elderly patients with 536 foot and ankle injuries were identified. Within this group, 237 (48%) patients with 294 injuries were sustained as a result of a high-energy mechanism. These mechanisms consisted of 170 motor vehicle accidents, 30 as a result of high (not ground level) energy falls, 2 from industrial accidents, and 35 classified as other, which included sports, blunt trauma, bicycle, airplane or boating accidents, crush injuries, and injuries resulting from a lawn mower. The injuries produced were 17 metatarsal fractures, 9 Lisfranc injuries, 10 midfoot (navicular, cuneiform, or cuboid) fractures, 23 talus fractures, 63 calcaneal fractures, 73 unimalleolar, bimalleolar, or trimalleolar ankle fractures, 45 pilon fractures, and 3 pure dislocations of the foot or ankle. Overall, 243 (83%) of these injuries underwent surgical fixation and data have shown that when surgery is used to manage high-energy injuries of the foot and ankle in the elderly individuals, the complications and outcomes are similar to those seen in younger patients. Therefore, the decision for surgical intervention for high-energy injuries of the foot and ankle should be based primarily on the injury pattern and not solely on the age of the patient.

A retrospective comparison of first metatarsophalangeal joint arthrodesis using a locked plate and compression screw technique

INTRODUCTION

The historic primary treatment for end-stage first metatarsophalangeal (MTP) joint arthritis has been fusion. Traditionally, this has been accomplished by metaphyseal apposition between the proximal phalanx and metatarsal using crossed compression screws. Recently, locked plates have been introduced that help support this technique by offering added stability. We present our experience with 45 first MTP fusions in 45 feet using a locked plate and compression screw.

METHODS

A retrospective review of 45 patients who met the study criteria with a hallux rigidus correction using a locked plate with a compression screw was performed. Charts and radiographs were independently reviewed by 2 authors not involved in the index procedures to assess outcomes.

RESULTS

There was a 93% fusion rate (42/45 feet) with 3 nonunions. The mean time to union was 51.1 days (range = 29-116 days, SD = 24.4). The mean patient age was 58.1 years (range = 29-80 years, SD = 10.1). The mean time to partial weight bearing was 7.0 days (range = 0-53 days, SD = 13.8) and the mean time to full weight bearing was 62.0 days (range = 29-57 days, SD = 17.9).

DISCUSSION

We report on the results of first MTP fusion using a compression screw and locked plate technique. The results show that this is an effective means of creating a first MTP joint arthrodesis.