Bone mineral density after removal of rigid plates from forearm fractures: preliminary report

Risk Factors for Complications in Ulnar Shortening Osteotomies: A Multicenter Retrospective Review

PURPOSE

Ulnar shortening osteotomy (USO) is commonly performed to alleviate pathologies causing ulnar-sided wrist pain. Surgical complications include nonunion and hardware removal, with rates up to 18% and 45%, respectively. The primary objective of the study was to report the overall complication rate of USO. The secondary objective was to identify risk factors for complications.

METHODS

A retrospective multicenter cohort review was undertaken, including six Canadian cities over a 6-year period (January 2013-December 2018). Chart review was used to collect demographic data, surgical technique, implant used, and postoperative complications. Descriptive statistics of demographics and operative characteristics, including plate positioning, type of osteotomy, plate type, and ulnar variance (mm), were analyzed. Univariate analyses were used to select predictor variables for nonunion and hardware removal. These predictor variables were then entered into an adjusted multivariable logistic regression model.

RESULTS

A total of 361 USOs were performed. Mean age was 46 ± 16 years (60.7% men). The overall complication rate was 37.1%, hardware removal rate was 29.6%, and nonunion rate was 9.4%. There was a workers' compensation claim associated with 21.6% of all complications, and it was a risk factor for both hardware removal (odds ratio [OR] = 3.81) and nonunion (OR = 2.88). Neither smoking nor diabetes was associated with complication rates. Seventy percent of plates were placed volarly, 25.5% dorsally, and 3.9% directly ulnar. Osteotomies were oblique in 83.7% of cases and transverse in 15.5%. Adjusted multivariate regression analysis revealed that younger age (OR = 0.98) was a risk factor for hardware removal and male sex (OR = 2.49) was a risk factor for nonunion. A surgical factor associated with hardware removal was direct ulnar plate placement (OR = 9.93). No surgical factors were associated with nonunions.

CONCLUSIONS

There are substantial rates of complications with USOs. Direct ulnar plate placement should be avoided. Patients should be thoroughly counseled on the risks of complications prior to proceeding with USO.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Complications of Hardware Removal in Pediatric Orthopaedic Surgery

BACKGROUND

Hardware removal (HR) is one of the most common surgical procedures in pediatric orthopaedics. Surgeons advocate for HR for a variety of reasons, including to limit peri-implant fracture risk, restore native anatomy for adult reconstruction surgery, permit bone growth and development, and mitigate implant-related pain/irritation. To our knowledge, no recent study has investigated the characteristics and complications of HR in pediatric orthopaedics. The goal of this study is to report the prevalence and complications of hardware removals across all of pediatric orthopaedic surgery.

METHODS

A retrospective case series was conducted of all hardware removals from 2012 to 2023 performed at a single urban tertiary-care children's hospital. Cases were identified using CPT codes/billing records. Spinal hardware and cases for which hardware was either implanted or explanted at an outside hospital were excluded. Patient demographic and clinical data were recorded. For patients with multiple hardware removals, each case was recorded independently.

RESULTS

A total of 2585 HR cases for 2176 children met study criteria (57.7% male; mean age 12.3±4.4 y). The median postoperative follow-up time was 1.7 months (interquartile range: 0.6 to 6.9). The most common sites of hardware removal were the femur/knee (32.7%), tibia/fibula/ankle (19.3%), and pelvis/hip (18.5%). The most common complications included sustained, new-onset postoperative pain (2.6%), incomplete hardware removal (1.6%), and perioperative fracture (1.4%). The overall complication rate of hardware removal was 9.5%. Eighty-eight percent of patients who underwent hardware removal for pain experienced pain relief postoperatively. HR >18 months after insertion had a 1.2x higher odds of overall complication ( P =0.002) and 3x higher odds of incomplete removal/breakage ( P <0.001) than hardware removed 9 to 18 months after insertion.

CONCLUSIONS

The overall complication rate of hardware removal across a large series in the pediatric population was 9.5%. Despite hardware removal being one of the most common and often routine procedures in pediatric orthopaedics, the complication rate is not benign. Surgeons should inform patients and families about the likelihood of success and the risks of incomplete removal during the informed consent process.

LEVEL OF EVIDENCE

IV.

Recovery of Forearm Bone Strength After Plate Removal: A Finite Element Analysis Study

PURPOSE

The purpose of this study was to estimate the bone strength after plate removal over time and to investigate the progression of bone strength recovery.

METHODS

A consecutive series of 31 patients was investigated to evaluate bone strength before and after forearm plate removal. Patients who were included underwent plate fixation for forearm diaphyseal fractures and were scheduled for plate removal. Computed tomography (CT) scans of the entire length of the bilateral forearms were taken before plate removal and at 1, 3, and 6 months after surgery. Patient-specific CT-based finite element analysis was used to predict the forearm bone fracture strength against an axial load (N), defined as the bone strength. Bone strength was estimated by patient-specific CT-based finite element analysis at each time point.

RESULTS

The mean age of the patients was 40.4 years. The mean time between plate fixation and removal was 27.5 months. Bone strength before the removal was estimated as reduced to 47% of that of the uninjured side. This was constant regardless of age group, involvement of the radius or ulna, Arbeitsgemeinschaft für Osteosynthesefragen (AO) classification, open fracture, or type of plate. Bone strength at 1, 3, and 6 months after removal was estimated to be 66%, 85%, and 97%, respectively. The bone strength of the distal ulna was weaker than that at the other sites in the forearm and showed delayed recovery.

CONCLUSIONS

Bone strength after plate removal showed recovery within 3-6 months and was fully recovered by 6 months. The degree of recovery of bone atrophy varies from site to site, and patients should be careful about refracture after removal.

CLINICAL RELEVANCE

Clinicians should be aware that bone strength may not be sufficiently restored even 6 months after plate removal of forearm fractures.

Indications for the removal of implants after fracture healing: A comparison between human and veterinary medicine

Indications for implant removal after fracture healing are still under debate in both human and veterinary medicine. Although hardware removal is a common procedure, it should not be undertaken lightly. Intra and post-operative complications are common and a thorough evaluation of the risks and benefits should be performed. This review aimed to collect and summarise published data on the indications for implant removal in small animals, compare the collected data with human and equine medicine, and investigate the existence of guidelines for this purpose. There is no international consensual agreement for implant removal after fracture healing, neither in small animals nor in human orthopaedics. Decision-making processes are still controversial in some scenarios, thus clear evidence-based protocols for implant removal are needed.

Finite element analysis of the biomechanical effects of titanium and Cfr-peek additively manufactured subperiosteal jaw implant (AMSJI) on maxilla

The aim of this study is to examine the stresses that will occur under occlusal forces on the cortical bone, spongious bone and the subperiosteal implant systems made of Titanium and%60 Carbon fiber reinforced Polyether ether ketone (PEEK) material. Two different models of subperiosteal implant systems on maxilla made of Titanium and %60 Carbon fiber reinforced Polyether ether ketone (PEEK) material. As a result of vertical and oblique forces, the stress values and distributions on the subperiosteal implant systems and bone were examined. After applying the three different force protocols, von Mises stress, Maximum principal stress and Minimum principal stress values and distribution on the subperiosteal implant body, fixation screws, cortical and spongious bone were analyzed by finite element analysis. In all scenarios, the von Mises values ​​on the Titanium subperiosteal implant system were found to be approximately twice on the 60% carbon fiber reinforced PEEK subperiosteal implant system plates. Subperiosteal implants produced from titanium and carbon fiber reinforced PEEK material exhibited similar stress values on cortical and spongious bone. According to the results of this study, 60% Carbon fiber reinforced PEEK material can be considered as an alternative material to titanium since it exhibits similar biomechanical behavior with titanium subperiosteal implants on cortical and spongious bone. In order to be routinely used as dental subperiosteal implant material, it should be supported by long-term in vivo studies.

Emerging Technologies in Distal Radius Fracture Fixation

PURPOSE OF REVIEW

To provide an overview of emerging fixation constructs and materials used in the operative management of distal radius fractures.

RECENT FINDINGS

The indications, advantages, and disadvantages of relatively new implants and devices used to treat distal radius fractures are discussed. These include the intramedullary nail, intramedullary cage, radiolucent volar locking plate, distal radius hemiarthroplasty, and bone graft substitutes. The spectrum of distal radius fracture patterns may make it impossible to depend on a single device for fixation, and surgeons managing distal radius fractures should be adept at using various surgical approaches, techniques, and hardware systems. Additional studies demonstrating the cost-effectiveness, biomechanical properties, and clinical outcomes will be useful in determining the utility of the described techniques.

Biomechanical comparison between stainless steel, titanium and carbon-fiber reinforced polyetheretherketone volar locking plates for distal radius fractures

INTRODUCTION

As the popularity of volar locked plate fixation for distal radius fractures has increased, so have the number and variety of implants, including variations in plate design, the size and angle of the screws, the locking screw mechanism, and the material of the plates.

HYPOTHESIS

Carbon-fiber reinforced polyetheretherketone (CFR-PEEK) plate features similar biomechanical properties to metallic plates, representing, therefore, an optimal alternative for the treatment of distal radius fractures.

MATERIALS AND METHODS

Three different materials-composed plates were evaluated: stainless steel volar lateral column (Zimmer); titanium DVR (Hand Innovations); CFR-PEEK DiPHOS-RM (Lima Corporate). Six plates for each type were implanted in sawbones and an extra-articular rectangular osteotomy was created. Three plates for each material were tested for load to failure and bending stiffness in axial compression. Moreover, 3 constructs for each plate were evaluated after dynamically loading for 6000 cycles of fatigue.

RESULTS

The mean bending stiffness pre-fatigue was significantly higher for the stainless steel plate. The titanium plate yielded the higher load to failure both pre and post fatigue. After cyclic loading, the bending stiffness increased by a mean of 24% for the stainless steel plate; 33% for the titanium; and 17% for the CFR-PEEK plate. The mean load to failure post-fatigue increased by a mean of 10% for the stainless steel and 14% for CFR-PEEK plates, whereas it decreased (-16%) for the titanium plate. Statistical analysis between groups reported significant values (p<001) for all comparisons except for Hand Innovations vs. Zimmer bending stiffness post fatigue (p=.197).

DISCUSSION

The significant higher load to failure of the titanium plate, makes it indicated for patients with higher functional requirements or at higher risk of trauma in the post-operative period. The CFR-PEEK plate showed material-specific disadvantages, represented by little tolerance to plastic deformation, and lower load to failure.

LEVEL OF EVIDENCE

N/A.

Evaluation of Bone Atrophy After Treatment of Forearm Fracture Using Nonlinear Finite Element Analysis: A Comparative Study of Locking Plates and Conventional Plates

PURPOSE

Forearm diaphysis fractures are usually managed by open reduction internal fixation. Recently, locking plates have been used for treatment. In the long-term period after surgery, some patients present with bone atrophy adjacent to the plate. However, a comparison of locking and conventional plates as a cause of atrophy has not been reported. The aim of this study was to investigate long-term bone atrophy associated with use of locking and conventional plates for forearm fracture treatment.

METHODS

In this study we included 15 patients with forearm fracture managed by either locking or conventional plates and with more than 5 years of follow-up. Computed tomographic imaging of both forearms was performed to assess bone thickness and local bone mineral density and to predict bone strength without plate reinforcement based on finite element analysis.

RESULTS

Mean patient age at surgery was 48.0 years. Eight patients underwent reduction with fixed locking plates and were followed up for a mean of 79.5 months; the remaining 7 patients were treated with conventional plates and were followed up for a mean of 105.0 months. Compared with the conventional plate group, the locking plate group had the same fractured limb-contralateral limb ratio of cortex bone thickness, but had significantly lower ratios of mineral density adjacent to the plate and adjusted bone strength.

CONCLUSIONS

This study demonstrated bone atrophy after locking plate fixation for forearm fractures. Treatment plans for forearm fracture should take into consideration the impact of bone atrophy long after plate fixation.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Accuracy of specimen-specific nonlinear finite element analysis for evaluation of radial diaphysis strength in cadaver material

The feasibility of a user-specific finite element model for predicting the in situ strength of the radius after implantation of bone plates for open fracture reduction was established. The effect of metal artifact in CT imaging was characterized. The results were verified against biomechanical test data. Fourteen cadaveric radii were divided into two groups: (1) intact radii for evaluating the accuracy of radial diaphysis strength predictions with finite element analysis and (2) radii with a locking plate affixed for evaluating metal artifact. All bones were imaged with CT. In the plated group, radii were first imaged with the plates affixed (for simulating digital plate removal). They were then subsequently imaged with the locking plates and screws removed (actual plate removal). Fracture strength of the radius diaphysis under axial compression was predicted with a three-dimensional, specimen-specific, nonlinear finite element analysis for both the intact and plated bones (bones with and without the plate captured in the scan). Specimens were then loaded to failure using a universal testing machine to verify the actual fracture load. In the intact group, the physical and predicted fracture loads were strongly correlated. For radii with plates affixed, the physical and predicted (simulated plate removal and actual plate removal) fracture loads were strongly correlated. This study demonstrates that our specimen-specific finite element analysis can accurately predict the strength of the radial diaphysis. The metal artifact from CT imaging was shown to produce an overestimate of strength.

Selective screw placement in forearm compression plating: results of 75 consecutive fractures stabilized with 4 cortices of screw fixation on either side of the fracture

OBJECTIVES

To (1) assess the effectiveness of an alternative plate and screw construct for all diaphyseal forearm fracture patterns and (2) test the hypothesis that as the working length (WL) to plate length (PL) ratio increases, so does the construct instability and therefore likelihood of failure.

DESIGN

Retrospective.

SETTING

Level 1 trauma center.

PATIENTS/PARTICIPANTS

Sixty-three patients were operatively treated and 53 were available for follow-up, totaling 75 diaphyseal fractures (19 ulna, 12 radius, and 22 radius/ulna). Average follow-up was 14.6 months (8-26).

MAIN OUTCOME MEASUREMENTS

Patients were followed postoperatively at 1 to 2 weeks, 6 weeks, 10 weeks, 4 months, and then at 3 month intervals. Radiographs were analyzed for changes in fracture alignment, loose or broken hardware, and fracture-healing characteristics. Fracture union was defined when a fracture was radiographically healed and clinically asymptomatic, and the patient was able to return to all activities without restrictions.

RESULTS

No fractures showed radiographic evidence of changes in alignment after fixation. There were no refractures, no infections, and one nonunion. The overall union rate after the index procedure was 97.1% for the radius and 97.6% for the ulna. WL:PL ratio averaged 0.17 (range 0-0.57) and the most frequently used PL was 7 holes (n=43). Patients with closed fractures did have a significantly reduced time to union when compared to those with open fractures (P=0.002). Overall union rate averaged 9.8 weeks (range 6-32 weeks).

CONCLUSIONS

Fixation with a standard length compression plate and four cortices of screw fixation on either side of the fracture seems to be a stable construct for diaphyseal forearm fractures and may result in union rates equivalent to those cited in the literature.

Plate removal after ulnar-shortening osteotomy

PURPOSE

Ulnar-shortening osteotomy using plate and screw fixation is a reliable method for treating various wrist disorders. In some patients the plate remains as a source of discomfort even after the osteotomy has healed and the preoperative complaints have resolved. There is not a large body of information to guide the surgeon in the timing of plate removal should it be needed to address persistent forearm complaints caused by prominent hardware. This study investigated the outcome of patients who had removal of the plate because of persistent symptoms after undergoing ulnar-shortening osteotomy once radiographic healing was apparent.

METHODS

A consecutive series of 40 ulnar shaft-shortening osteotomies was performed in which 14 patients requested removal of the plate because of persistent tenderness despite nonsurgical management. There were 12 Rayhack (11 titanium, 1 stainless steel) and 2 Synthes 3.5-mm dynamic compression titanium plates used. Before removal radiographic union was documented by 2 sets of films taken in multiple planes at least 4 weeks apart. The average time to plate removal was 6.6 months.

RESULTS

All patients had resolution of the ulnar forearm pain after hardware removal. There were no repeated surgeries and all patients returned to their prior levels of activity or employment. Patients were followed-up for an average of 17 months after plate removal. There was 1 refracture in an osteoporotic patient when she fell down a flight of stairs 7 months after plate removal.

CONCLUSIONS

When used for fixation after ulnar shaft-shortening for ulnar-sided wrist pain of various causes 3.5-mm compression plates seem to be removable at 6 to 9 months in symptomatic patients with a low risk for refracture when sequential sets of x-rays confirm healing of the osteotomy site according to this small series of patients.