Proximal Humeral Bone Loss in Revision Shoulder Arthroplasty.

Proximal humeral bone loss in revision shoulder arthroplasty poses a significant obstacle to achieving stable and reliable fixation of the humeral stem. It is important to identify and classify this bone loss preoperatively, which can range from epiphyseal to substantial diaphyseal bone loss. There are several reconstructive options that can address the varying levels of bone loss, including cemented long-stem fixation, a composite construct using proximal humeral allograft or femoral allograft, proximal humeral endoprosthetic replacement, or total humeral replacement. All of these are viable reconstructive options that have demonstrated adequate to good outcomes.

Classification of bone flap resorption after cranioplasty: a proposal for a computed tomography-based scoring system.

BACKGROUND: Bone flap resorption (BFR) is the most prevalent complication resulting in autologous cranioplasty failure, but no consensus on the definition of BFR or between the radiological signs and relevance of BFR has been established. We set out to develop an easy-to-use scoring system intended to standardize the interpretation of radiological BFR findings. METHODS: All 45 autologous cranioplasty patients operated on at Oulu University Hospital from 2004 to 2014 were identified, and the bone flap status of all the available patients was evaluated using the new scoring system. Derived from previous literature, a three-variable score for the detection of BFR changes is proposed. The variables "Extent" (estimated remaining bone volume), "Severity" (possible perforations and their measured diameter), and "Focus" (the number of BFR foci within the flap) are scored from 0 to 3 individually. Using the sum of these scores, a score of 0-9 is assigned to describe the degree of BFR. Additionally, independent neurosurgeons assessed the presence and relevance of BFR from the same data set. These assessments were compared to the BFR scores in order to find a score limit for relevant BFR. RESULTS: BFR was considered relevant by the neurosurgeons in 11 (26.8%) cases. The agreement on the relevance of BFR demonstrated substantial strength (κ 0.64, 95%CI 0.36 to 0.91). The minimum resorption score in cases of relevant BFR was 5. Thus, BFR with a resorption score ≥ 5 was defined relevant (grades II and III). With this definition, grade II or III BFR was found in 15 (36.6%) of our patients. No risk factors were found to predict relevant BFR. CONCLUSIONS: The score was proven to be easy to use and we recommend that only cases with grades II and III BFR undergo neurosurgical consultation. However, general applicability can only be claimed after validation in independent cohorts.

Bone resorption in autologous cryopreserved cranioplasty: quantitative evaluation, semiquantitative score and clinical significance.

BACKGROUND: Changes after reimplantation of the autologous bone have been largely described. However, the rate and the extent of resorption in cranial grafts have not been clearly defined. Aim of our study is to evaluate the bone flap resorption (BFR) after cryopreservation. METHODS: We retrospectively reviewed 27 patients, aged 18 years or older, subjected to cranioplasty (CP) adopting autologous cryopreserved flap. The BFR was derived from the percentage of decrease in flap volume (BFR%), comparing the first post-operative computed tomography (CT) and the last one available (performed at least 1 year after surgery). We also proposed a semiquantitative scoring system, based on CT, to define a clinically workable BFR classification. RESULTS: After a mean ± SE follow-up of 32.5 ± 2.4 months, the bone flap volume decreased significantly (p < 0.0001). The mean BFR% was 31.7 ± 3.8% and correlated with CT-score (p < 0.001). Three BFR classes were described: mild (14.8% of cases) consisting in minimal bone remodelling, CT-score ≤ 6, mean BFR% = 3.5 ± 0.7%; moderate (51.9% of cases) corresponding to satisfactory cerebral protection, CT-score < 13, mean BFR% = 25.6 ± 2.2%; severe (33.3% of cases) consisting in loss of cerebral protection, CT-score ≥ 13, mean BFR% = 54.2 ± 3.9%. Females had higher BFR% than males (p = 0.022). BFR classes and new reconstructive surgery were not related (p = 0.58). CONCLUSIONS: BFR was moderate or severe in 85.2% of re-implanted cryopreserved flaps. The proposed CT-score is an easy and reproducible tool to define resorption extent.

Customized implants for acetabular Paprosky III defects may be positioned with high accuracy in revision hip arthroplasty.

PURPOSE: In revision hip arthroplasty, custom-made implants are one option in patients with acetabular Paprosky III defects. METHODS: In a retrospective analysis, we identified 11 patients undergoing cup revision using a custom-made implant. The accuracy of the intended position of the implant was assessed on post-operative 3D CT and compared to the pre-operative 3D planning in terms of inclination, anteversion, and centre of rotation. In addition, the accuracy of post-operative plain radiographs for measuring implant position was evaluated in relation to the 3D CT standard. RESULTS: We found a mean deviation between the planned and the final position of the custom-made acetabular implant on 3D CT of 3.6° ± 2.8° for inclination and of - 1.2° ± 7.0° for anteversion, respectively. Restoration of center of rotation succeeded with an accuracy of 0.3 mm ± 3.9 mm in the mediolateral (x) direction, - 1.1 mm ± 3.8 mm in the anteroposterior (y) direction, and 0.4 mm ± 3.2 mm in the craniocaudal (z) direction. The accuracy of the post-operative plain radiographs in measuring the position of the custom-made implant in relation to 3D CT was 1.1° ± 1.7° for implant inclination, - 2.6° ± 1.3° for anteversion and 1.3 mm ± 3.5 mm in the x-direction, and - 0.9 mm ± 3.8 mm in the z-direction for centre of rotation. CONCLUSION: Custom-made acetabular implants can be positioned with good accuracy in Paprosky III defects according to the pre-operative planning. Plain radiographs are adequate for assessing implant position in routine follow-up.

Proximal femoral replacement in non-oncologic patients undergoing revision total hip arthroplasty.

PURPOSE: Proximal femoral replacements (PFRs) have been recently utilized in complex revision arthroplasties where proximal femoral bone is compromised. The purpose of this study is to evaluate the clinical outcomes, complications, and survivorship of PFRs as a salvage treatment for severe bone loss after non-oncologic revision total hip arthroplasty. METHODS: This is a retrospective review of all patients who underwent femoral revision surgery using a single design PFR between 2004 and 2013 at our institution. Forty patients (41 hips) were included with a mean age of 64 years (29-90). According to Paprosky classification, 15 femurs had type IIIB defect, and 26 had type IV defect. Patients were followed for a mean of five years (2-10). The average length of reconstruction was 150 mm (81-261). A Kaplan-Meier analysis was used to determine the survival of the PFR. RESULTS: A total of nine patients (9 PFRs, 22%) were re-operated upon. Three re-operations were for infection, two for dislocation, two for aseptic loosening, and two for periprosthetic fracture. The survivorship at five years was 95.1% for revision of the femoral stem for aseptic loosening. We did not find length of the segmental reconstruction or the indication for revision, to be a risk factor for implant failure or re-revision. CONCLUSIONS: Proximal femoral replacements have shown an acceptable survivorship in non-oncologic revision hip arthroplasties for severe proximal femoral bone loss. The frequent use of constrained liners may decrease the risk of dislocation due to the loss of the abductor mechanism encountered in these complex reconstructions.

Classification of Temporal Bone Pneumatization on High-Resolution Computed Tomography: Prevalence Patterns and Implications.

Objective The degree of pneumatization of the temporal bone has implications in the pathophysiology and surgical considerations of many temporal bone disorders. This study aims to identify common pneumatization patterns in the petrous apex, mastoid, and infralabyrinthine compartments of the temporal bone. Variables associated with temporal bone pneumatization were also identified. Study Design Case series with chart review. Setting Single tertiary hospital. Subjects and Methods In total, 299 high-resolution computed tomography scans of the temporal bone performed on patients between 2013 and 2016 were reviewed. Only normal temporal bone scans in patients aged 13 years and older were included. Previously published grading systems were used to classify pneumatization patterns in the petrous apex, mastoid, and infralabyrinthine region. Results The most common pneumatization pattern in the petrous apex was group 2 (less than half of the petrous apex medial to the labyrinth is pneumatized), that in the mastoid was group 4 (hyperpneumatization), and that in the infralabyrinthine region was type B (limited pneumatization), at 54.8%, 55.4%, and 76.0% of patients, respectively. Patients with increased pneumatization of 1 temporal bone compartment tended to have increased pneumatization of the same compartment on the contralateral side and the other compartments on the ipsilateral side ( P < .05). Younger age ( P < .001) and male sex ( P = .001) were associated with increased pneumatization in the petrous apex and infralabyrinthine compartments. Conclusion The degree of temporal bone pneumatization varies among the different compartments. Age and sex have a significant association with the degree of pneumatization of the petrous apex and infralabyrinthine compartment.

Humeral bone resorption after anatomic shoulder arthroplasty using an uncemented stem.

BACKGROUND: Bone resorption around the femoral stem after total hip arthroplasty is a well-known phenomenon. However, only a few studies have evaluated bone resorption after shoulder arthroplasty. This study investigated the prevalence of humeral bone resorption after different shoulder arthroplasty procedures. METHODS: The study included 147 shoulders that underwent total shoulder arthroplasty (TSA) or humeral head replacement (HHR) with an uncemented humeral stem from November 2008 to May 2015 and were monitored for more than 1 year. The prevalence of humeral bone resorption and risk factors were investigated. RESULTS: The most advanced grade of bone resorption, grade 0, occurred in 21 shoulders (14.3%). Grade 1 bone resorption occurred in 10 (6.8%), grade 2 in 28 (19.0%), grade 3 in 61 (41.5%), and grade 4 in 27 (18.4%). High occurrence of bone absorption was observed in zones 1, 2, and 7. Grade 4 bone resorption did not occur in zones 3 and 5. HHR, on-growth type stem coating, and occupation ratio were significant independent risk factors for grade ≥3 bone resorption, whereas female sex and HHR were significant independent risk factors for grade 4. CONCLUSION: Bone resorption was observed in 126 shoulders (85.7%), and full-thickness cortical bone resorption occurred in 27 shoulders (18.4%). Bone resorption was frequently observed at the greater tuberosity, lateral diaphysis, and calcar region (zones 1, 2, and 7). Significant risk factors included female sex, HHR with rotator cuff reconstruction, on-growth type stem coating, and high occupation ratio of the implant.

Classification and Analysis of Attritional Glenoid Bone Loss in Recurrent Anterior Shoulder Instability.

BACKGROUND: Recognition and proper treatment of glenoid bone loss (GBL) are important for successful management of anterior shoulder instability. Although GBL has been described as the amount of bony loss from the front of the glenoid, there is also a fragment of bone that is usually displaced and often undergoes attrition. Thus, due to attritional bone loss (ABL) of the fragment, insufficient bone is left to fully reconstruct the glenoid. PURPOSE: To (1) evaluate ABL of the glenoid fragment in recurrent anterior shoulder instability and (2) correlate ABL with clinical history, fragment size, and radiographic findings. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: GBL was evaluated on 3-dimensional computed tomography (3D CT) en-face view and was measured as percentage loss. The bone fragment size was measured, and attrition of the fragment was determined by evaluation of the amount remaining relative to the initial defect; patients were stratified into minimal (<34%), moderate (34% to <67%), and severe (≥67%) attritional loss groups. Clinical history and demographics were correlated to ABL, and GBL and ABL were compared. RESULTS: The overall median percentage GBL was 15.3% (interquartile range [IQR], 9.9%-20.0%), with a mean (±SD) percentage GBL of 16.5% ± 9.0%. Study participants had a corresponding median percentage ABL of 75.8% (IQR, 53.8%-95.7%) and a mean percentage ABL of 72.0% ± 24.4%. A total of 61.2% of patients (n = 85) exhibited severe ABL, while 30.2% had moderate ABL and 8.6% had minimal ABL. The total time of instability was significantly associated with percentage of attritional bone loss ( P < .05). In addition, the time of instability was greatest in patients in the third tertile of ABL (≥87.5%; P = .08). A significant difference was found in total time of instability among patients in the highest tertile of ABL (38.6 months) versus both the middle (26.7 months) and lowest (32.8 months) tertiles ( P < .05). CONCLUSION: The study results indicate that in the majority of patients with recurrent anterior instability, GBL presents with extensive attrition of the bone fragment independent of initial glenoid bone loss; therefore, surgeons should be cognizant that the remaining bone fragment is unable to reconstitute glenoid bone stock. In addition, the results showed more attritional bone loss in patients with a longer duration of instability symptoms, indicating a role for incorporating symptom duration in determining proper management.

Tantalum Cones in Revision Total Knee Arthroplasty.

The best strategy to address large bony defects in revision total knee arthroplasty has yet to be determined. The relatively recent development of porous tantalum cones and their use to address massive bone loss in knee arthroplasty has shown promising short- and intermediate-term results. The purpose of this review is to present the current literature on: (1) basic science of porous tantalum, (2) classification and treatment for bone loss, (3) clinical results, and (4) evolution of newer generation cones.

Coracoid bone graft resorption after Latarjet procedure is underestimated: a new classification system and a clinical review with computed tomography evaluation.

BACKGROUND: This study proposes a simple and reliable classification system to evaluate the severity of the bone resorption of the transferred coracoid bone block after the Latarjet procedure. The incidence and severity of the graft resorption was also investigated. METHODS: Between January 2009 and January 2012, 63 patients underwent an open Latarjet procedure and were included. Four independent surgeons used the classification system we proposed to evaluate the severity of the graft resorption on the computed tomography scan performed 1 year postoperatively. Each surgeon did the evaluation twice at a 3-month interval. The interobserver and intraobserver reliability of the classification system were analyzed using intraclass correlation coefficients. Among these 63 patients, 57 patients were available for clinical evaluation at 2 years postoperatively. RESULTS: The American Shoulder and Elbow Surgeons score, Constant-Murley score, and Rowe score were improved significantly after the surgery. No redislocation occurred during follow-up. The incidence of graft resorption was 90.5% based on the computed tomography evaluation. The coracoid graft resorption was classified as grade 0 in 6 patients, grade I in 26, grade II in 25, and grade III in 6. The classification system had excellent interobserver and intraobserver reliability. CONCLUSION: The open Latarjet procedure is effective in treating anterior shoulder instability with marked glenoid bone loss. The incidence of the graft resorption at 1 year postoperatively is high. Our classification system on the graft resorption after Latarjet procedure has good interobserver and intraobserver reliability.

Nueva clasificación de rebordes atróficos en el sector posterior maxilar para el tratamiento con implantes dentales / A new classification of atrophic ridges in the posterior jaw for the treatment with dental implants

El edentulismo en el sector posterior maxilar es una de las condiciones más comunes que se presenta en la consulta odontológica9, 10, 12. La prevalencia del edentulismo difiere sustancialmente en la mayoría de los países del mundo (4). Algunos de los índices más altos son encontrados en el Reino Unido y Nueva Zelandia, y los más bajos en Estados Unidos.

Effect of frequent application of low-level laser therapy on corticotomized tooth movement in dogs: a pilot study.

PURPOSE: The purposes of the present study were to evaluate the effects of frequent applications of low-level laser therapy (LLLT) on corticotomy-assisted tooth movement in a beagle dog model and to compare the effects in the mandible and maxilla. MATERIALS AND METHODS: In 4 male beagles, the maxillary and mandibular second premolars were extracted. The third premolars were corticotomized and then protracted from the canines with a continuous force of 200 g. Daily LLLT (using an aluminum gallium indium phosphide [AlGaInP] diode) was applied at the buccal mucosa of the corticotomized premolars on 1 side only. The tooth movement was measured for 8 weeks. Fluorochromes were injected intravenously at the start of the experiment (T0) and after 2 (T2), 4 (T4), and 8 (T8) weeks to evaluate new bone formation on the tension sides. Histomorphometric and immunohistologic evaluations were performed. RESULTS: In the mandible, the movement of the corticotomized premolars in the LLLT plus corticotomy group was less than that in the corticotomy-only group, although the difference was not statistically significant. In the maxilla, no significant differences between the 2 groups were found. Osteoclastic and proliferating cell activities and the amount of new bone formation were greater in the mandibular LLLT plus corticotomy group than in the corticotomy-only group. CONCLUSIONS: The frequent application of LLLT showed no significant effect on the corticotomized tooth movement.

Stress shielding around radial head prostheses.

PURPOSE: Stress shielding is known to occur around rigidly fixed implants. We hypothesized that stress shielding around radial head prostheses is common but nonprogressive. In this study, we present a classification scheme to support our radiographic observations. METHODS: We reviewed charts and radiographs of 86 cases from 79 patients with radial head implants from both primary and revision surgeries between 1999 and 2009. Exclusion criteria included infection, loosening, or follow-up of less than 12 months. We classified stress shielding as: I, cortical thinning; II, partially (IIa) or circumferentially (IIb) exposed stem; and III, impending mechanical failure. RESULTS: Of 26 well-fixed stems, 17 (63%) demonstrated stress shielding: I = 2, II = 15 (IIa = 12, IIb = 3), and III = 0. We saw stress shielding with all stem types: cemented or noncemented; long or short; and straight, curved, or tapered. The only significant difference was that stems implanted into the radial shaft had less stress shielding than stems implanted into the neck or tuberosity (P = .03). The average follow-up was 33 months (range, 13-70 mo). Stress shielding was detectable by an average of 11 months (range, 1-15 mo). The pattern of bone loss was similar in 16 of 17 cases (94%), starting on the outer periosteal cortex. The 3 cases with circumferential exposure of the stem (stage IIb) averaged 2.6 mm (range, 1-4 mm) of exposed stem. Stress shielding never extended to the bicipital tuberosity, and there were no cases of impending mechanical failure. CONCLUSIONS: Stress shielding around radial head prostheses is common, regardless of stem design. However, it is typically minor, nonprogressive, and of questionable clinical consequence. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

The influence of perforating the autogenous block bone and the recipient bed in dogs. Part I: a radiographic analysis.

OBJECTIVES: This study evaluated radiographically the integration and volume maintenance of grafted autogenous block bone under various cortical bone perforation conditions in dogs. MATERIAL AND METHODS: Five mongrel dogs were used. Each dog received four differently prepared onlay block bone grafts: a solid block graft was fixed on either (1) a cortically perforated recipient bed (SGPR) or (2) a nonperforated recipient bed (SGNPR), a perforated block graft was fixed on either (3) a nonperforated recipient bed (PGNPR) or (4) a cortically perforated recipient bed (PGPR). The animals were sacrificed at 1 day, 4 days, 10 days, 4 weeks, and 8 weeks after surgery. Specimens were prepared and radiographic analysis was conducted by using micro-computed tomography. The residual bone volume (RBV; mm(3) ), cross-sectional bone area (BA; mm(2)), and residual height (RH; %) of the grafted block bone were measured radiographically. RESULTS: The interface between the recipient bed and the graft showed no signs of bone integration at 1, 4, and 10 days of healing. However, at 4 weeks of healing, bone integration was observed in all groups. The RBV, BA, and RH of the grafts gradually decreased by 4 weeks of healing. At 8 weeks, the PGPR condition exhibited a higher RBV, BA, and RH than the other conditions, whereas the SGNPR condition exhibited the lowest RBV, BA, and RH. CONCLUSION: Within the limitations of this study, it can be concluded that intentional cortical perforation on the recipient bed and block bone graft may influence volume maintenance of the graft.

Review article: bone defect classifications in revision total knee arthroplasty.

There are several classification systems for bone defects in revision total knee arthroplasty. Each has its own drawbacks, and none satisfies all the clinical demands. Therefore, a new classification system and treatment guideline based on a combination of criteria (location, side, containment, and severity of the bone defect) is necessary.

Ambiguity in bone tissue characteristics as presented in studies on dental implant planning and placement: a systematic review.

OBJECTIVES: To survey definitions of bone tissue characteristics and methods of assessing them in studies of dental implant planning and placement. MATERIAL AND METHODOLOGY: Three databases were searched using specified indexing terms. Three reviewers selected from the titles and retrieved abstracts in accordance with inclusion and exclusion criteria. Descriptions of bone tissue characteristics (bone quality, density and quantity) used before or during dental implant placement were searched for and categorized. RESULTS: The search yielded 488 titles. One hundred and fort-nine publications were selected and read in full text. One hundred and eight were considered relevant. There were many different definitions and classification systems for bone tissue characteristics and examination protocols. Approximately two-third of the included publications reported the Lekholm & Zarb classification system for bone quality and quantity. However, only four studies implemented the Lekholm & Zarb system as originally proposed. A few publications described bone quality in accordance with the Misch or Trisi and Rao classifications systems. Assessment methods were often described only briefly (or not at all in one-fifth of the publications). Only one study presented the diagnostic accuracy of the assessment method, while only two presented observer performance. CONCLUSION: The differing definitions and classification systems applied to dental implant planning and placement make it impossible to compare the results of various studies, particularly with respect to whether bone quality or quantity affect treatment outcomes. A consistent classification system for bone tissue characteristics is needed, as well as an appropriate description of bone tissue assessment methods, their diagnostic accuracy and observer performance.

The multiple faces of autoimmune-mediated bone loss.

Inflammation perturbs normal bone homeostasis and is known to induce bone loss, as it promotes both local cartilage degradation and local and systemic bone destruction by osteoclasts, as well as inhibits bone formation by osteoblasts. Thus, not surprisingly, inflammatory autoimmune diseases often lead to local and/or general bone loss. However, the mechanisms that target the bone in autoimmune disease are complex and diverse, as they range from a direct attack on the bone and cartilage by the immune cells to indirect consequences of disturbances of the systemic control of bone remodeling. This Review discusses current understanding of the mechanisms of autoimmune-mediated bone loss in view of new insight from two new fields of research: osteoimmunology, which analyzes the direct effect of immune cells on bone, and the integrative metabolism approach, which established the existence of neuroendocrine loops that regulate bone remodeling.

A comparison of the validity and reliability of established bone stock loss classification systems and the proposal of a novel classification system.

The classification and management of aseptic loosening of total hip arthroplasty remains a distinct challenge to the modern orthopaedic surgeon. The aim of this study was to assess the inter-observer and intra-observer reliability of commonly used classification systems for the assessment of bone stock loss in revision hip surgery. Radiographs of 23 femoral and 32 acetabular components in 30 patients were assessed using the Paprosky, AAOS and Endo-Klinik classification systems. A novel classification system was introduced and also used to assess the radiographs. Assessment was undertaken by 3 surgeons on 2 separate occasions and the inter- and intra- observer reliability calculated. The novel classification system showed a good to very good intra-observer reliability for both femoral and acetabular components (0.77-1.0; p<0.001), performing better than the other systems assessed. The novel femoral system demonstrated moderate to good inter-observer agreement (0.46-0.73), performing as well as the Paprosky (0.63-0.80) and AAOS (0.63-0.68) femoral systems. The novel acetabular system demonstrated fair to moderate inter-observer reliability (0.35-0.51) performing better than the AAOS acetabular classification (0.07-0.10) and as well as the Paprosky acetabular classification system (0.59-0.60). We propose this novel system as an alternative method for assessing bone stock loss in revision hip surgery.

Grading acetabular defects: the need for a universal and valid system.

Preoperative classification of acetabular bone loss in revision total hip arthroplasty has been problematic. An evidence-based approach involves having a validated and widely accepted system of classification. A prerequisite would be a system that describes each defect in terms that are mutually exclusive, hierarchical, surgically relevant, and corresponding to experienced clinicians' preoperative estimates of surgical complexity. Of the 6 systems reviewed, only 1 demonstrated the reliability and validity required for a standardized grading system. Although high-grade defects were seen in only 17% of the 1094 hips, the failure rate associated with them was 30%. A larger population of high grade defects is necessary to determine which treatment alternatives are successful.