Vilijam Zdravkovic

How bone quality may influence intraoperative and early postoperative problems after angular stable open reduction–internal fixation of proximal humeral fractures

BACKGROUND With the introduction of the deltoid tuberosity index (DTI), a simple radiographic tool has become available to measure bone mineral density of the proximal humerus. The aim of this study was to assess the influence of local bone mineral density on the early failure rate after angular stable open reduction-internal fixation of proximal humeral fractures (PHFs). METHODS We retrospectively followed up all patients treated with angular stable implants for PHFs from 2007 to 2014. The fractures were classified according to Neer, and the DTI, metaphyseal head extension (MHE), medial hinge displacement, and quality of reduction were assessed. Failures were defined as head screw cutouts. RESULTS The study included 146 patients (mean age, 66 years; range, 20-94 years). The mean follow-up period was 11 months (range, 3-94 months). Of the fractures, 91% were classified as 2- or 3-part fractures and 9% as 4-part fractures. The mean DTI was 1.44 (range, 1.19-2.11), and the mean MHE was 12 mm (range, 0-48 mm). The reduction result was at least acceptable in 80% of fractures. Screw cutouts were found in 23%. The DTI and MHE were the most significant preoperative predictors for the reduction result. The DTI (P = .036) and age (P = .02) were independent preoperative factors, and a good reduction (P = .001) was the only intraoperative factor influencing cutout. DISCUSSION This study proves that good bone quality and a long MHE are helpful for the reduction. Furthermore, good bone quality, a younger age, and a good reduction prevent later cutout. We conclude that local bone quality is a relevant factor in the treatment plan for PHFs.

The influence of local bone quality on fracture pattern in proximal humerus fractures

INTRODUCTION Bone mineral density and fracture morphology are widely discussed and relevant factors when considering the different treatment options for proximal humerus fractures. It was the aim of this study to investigate the influence of local bone quality on fracture patterns of the Neer classification as well as on fracture impaction angle in these injuries. MATERIALS AND METHODS All acute, isolated and non-pathological proximal humerus fractures admitted to our emergency department were included. The fractures were classified according to Neer and the humeral head impaction angle was measured. Local bone quality was assessed using the Deltoid Tuberosity Index (DTI). The distribution between DTI and fracture pattern was analysed. RESULTS 191 proximal humerus fractures were included (61 men, mean age 59 years; 130 women, mean age 69.5). 77 fractures (40%) were classified as one-part, 72 (38%) were two-part, 24 (13%) were three- and four-part and 18 (9%) were fracture dislocations. 30 fractures (16%) were varus impacted, whereas 45 fractures (24%) were classified as valgus impacted. The mean DTI was 1.48. Valgus impaction significantly correlated with good bone quality (DTI ≥ 1.4; p = 0.047) whereas no such statistical significance was found for the Neer fracture types. DISCUSSION We found that valgus impaction significantly depended on good bone quality. However, neither varus impaction nor any of the Neer fracture types correlated with bone quality. We conclude that the better bone quality of valgus impacted fractures may be a reason for their historically benign amenability to ORIF. On the other hand, good local bone quality does not prevent fracture comminution.

10-Year Survival of Acetabular Reinforcement Rings/Cages for Complex Hip Arthroplasty

Introduction : Acetabular reinforcement rings/ cages (AR) are commonly used for reconstruction of bone defects in complex hip arthroplasty. The aim of this study was to retrospectively investigate the 10-year survival rate of Ganz reinforcement rings and Burch-Schneider cages used in a single institution. Material and Methods : Between September 1999 and June 2002 all ARs, implanted in one institution, were identified. All patients had regular clinical and radiographic follow-up and were included in this study. Their prospectively collected clinical and radiographic data was retrospectively analyzed. In case of death before the 10-year follow-up examination, patient’s families or their general practitioner was contacted by telephone. The main outcome measures were survival of the ARs and kind of revision surgery. Results : The 10-year survival rate was 77.7%. At 10-year follow-up, 5/60 (8,3%) patients could not be located and had to be excluded therefore. 27/55 (49,1%) were dead, whereof 22 had no revision of the ARs before death (after a mean of 66 months; range: 0 - 123). Of the remaining 28/55 (50,9%) patients, 23 patients (24 ARs) had no revision of the ARs. Conclusion : Despite the high mortality rate of this study’s collective, ARs for complex primary or revision total hip arthroplasty provided predictable long term results. Level of Evidence : Clinical investigation.

Rounded data have a high potential for false comparative statistical results as shown with elbow arc of motion

BACKGROUND AND HYPOTHESIS Visually measured range-of-motion (ROM) data are usually rounded to the nearest 5° interval and then recorded. Rounding might significantly influence the outcome of statistical tests. METHODS We performed numerical simulation of t test application on 2 datasets, as typically reported for the elbow flexion-extension arc of motion. The test was performed on exact data and then repeated on the same data rounded to the nearest 5° interval. The simulation input parameters were as follows: difference in means (1°-30°), standard deviation (1°-30°), and number of cases (15, 30, 60, and 120). Diverging results were counted to find the rate of failure. RESULTS Depending on the given difference in means, the given standard deviation, and the number of cases, the failure rate of the t test after rounding reached up to 40%. DISCUSSION AND CONCLUSION The accuracy of statistical tests performed on rounded ROM data is limited because of loss of information after rounding to the nearest 5° interval. This affects parametric and nonparametric tests, as well as paired and unpaired tests. In the future, authors should specify how ROM has been measured and recorded, explicitly addressing rounding. Furthermore, to test a zero hypothesis on rounded ROM data, authors should apply our P value (α) correction.

The posterior ridge of the greater tuberosity of the humerus: a suitable landmark for the posterior approach to the shoulder joint?

BACKGROUND The purpose of this study was to evaluate the posterior ridge of the greater tuberosity, a palpable prominence during surgery, as a landmark for the posterior approach to the glenohumeral joint. METHODS Twenty-five human cadaveric shoulders were dissected. In 5 cases, a full-thickness rotator cuff tear was present. The posterior surgical anatomy was defined, and the distance from the ridge to the interval between the infraspinatus (IS) and teres minor (TM) muscle, the distance from the ridge to the inferior border of the glenoid (IBG), and the distance between the IS-TM interval and the IBG were determined. RESULTS In all specimens, a prominent ridge on the posterior greater tuberosity lateral to the articular margin could be identified. The IS-TM interval was located, on average, 3 mm proximal to this ridge. The IS-TM interval corresponded to a point 5 mm proximal to the IBG. In all shoulders, the ridge was located, on average, 8 mm proximal to the IBG. The plane of the IS-TM interval showed a vertically oblique direction. CONCLUSION The posterior ridge of the greater tuberosity is a suitable landmark to locate the internervous plane between the IS and TM and should not be crossed distally. Unlike other landmarks, the ridge moves with the humeral head, making it is less dependent on the patients size, sex, and arm position and the quality of the rotator cuff. The ridge is always located proximal to the insertion of the TM and IBG.

Femoral Bone Restoration Patterns in Revision Total Hip Arthroplasty Using Distally Fixed Modular Tapered Titanium Stems and an Extended Trochanteric Osteotomy Approach

BACKGROUND Mechanical failure of modular revision stems is a serious complication in revision total hip arthroplasty. The lack of adequate osseous support to the proximal component, especially in cases of an extended trochanteric osteotomy approach, is considered a risk factor for stem failure. In this study, we analyze proximal bone regeneration patterns in patients undergoing revision total hip arthroplasty for aseptic stem loosening through an extended trochanteric osteotomy approach using an uncemented dual modular stem. METHODS Fifty-four patients treated for aseptic stem loosening were radiologically reviewed. The femur was divided according to the Gruen zones. Preoperative bone loss, formation of new cancellous bone, and presence of direct osseous contact to the stem were noted right away for each Gruen zone. The presence of osseous support at the modular junction and the proximal component were examined. RESULTS All patients showed restoration of proximal bone mass at final follow up. New bone formation was first seen in more distally located Gruen zones. Cases with longer proximal components had a trend toward earlier osseous support at the modular junction. Overall, 75% of patients showed osseous support at the modular junction 2 years after surgery. CONCLUSION Restoration of proximal bone occurs in a distal to proximal direction. Shorter proximal components require more time until osseous support to the modular junction is achieved, which may result in a higher risk of mechanical failure. Based on this study, bony support at the modular junction should not be expected in 25% of cases 2 years after surgery.

Reliability of scapular kinematics estimated with three-dimensional motion analysis during shoulder elevation and flexion

BACKGROUND Knowing the reliability of three-dimensional motion analysis to evaluate scapular kinematics during upper limb movements is essential to plan further research dedicated to understanding scapulothoracic joint movements relative to the global shoulder motion. RESEARCH QUESTION The aim of this study was to assess the intra-subject as well as intra- and interrater reliability of scapulothoracic joint angles during shoulder elevation in scapular plane and shoulder flexion. METHODS Twenty healthy participants (26.6 ± 3.5 years) were asked to perform maximum shoulder elevation in scapular plane as well as shoulder flexion. Reliability was assessed using the intraclass correlation coefficient (ICC) and its 95% confidence interval of scapular kinematics (rotation, tilting, pro-retraction) at each degree of global motion (shoulder elevation or shoulder flexion) between 0° to 150°. RESULTS ICCs above 0.60 were accepted as good indicators for reliability. Intra-subject reliability was found to be very high (>0.9 for most part) for all scapulothoracic joint angles during both movements. Intra- and interrater reliability also showed good reliability being above 0.60 for the most part (except scapula tilting during shoulder elevation). Scapular kinematics showed low reliability during the respective first 10° and 20° of shoulder elevation and shoulder flexion. Furthermore, decreasing reliability was found above 120° of shoulder elevation or flexion. SIGNIFICANCE This study generally showed good to high levels of reliability in the range of interest (20-120°) in evaluating scapula kinematics in healthy adults during shoulder elevation and flexion; these results are important for future research providing a better understanding of scapular kinematics.

A new parallel closing mechanism for the laminectomy rongeur makes it significantly more precise: a biomechanical and mechanical comparison study

PurposeTo prove that a modified closing mechanism of the rongeur gives better precision compared to the old Kerrison rongeur.MethodsForty persons from the departments of orthopaedic surgery, urology and neurosurgery (35 orthopaedic, 2 urology and 3 neurosurgery) took part in the study. All participants were asked to punch ten times in a first step with either the old Kerrison rongeur with the scissors-like handle or the modified punch with a new parallel closing mechanism. In a second step, they punched 10 times with the other instrument. Shaft movement in three dimensions was measured with a stereoscopic, contactless, full-field digital image correlation system.ResultsThe new rongeur is significantly more precise with less movement in all three dimensions. The mechanical model of the new rongeur shows that the momentum needed to keep the tip at the initial position changes only minimally during the closing act on the new model.ConclusionThe new rongeur is more precise compared to the old Kerrison model. It is more robust against changes in the direction of the finger forces and may reduce soreness, fatigue and CTS in spine surgeons.Level of evidenceNot applicable: technical study.

Validating the forgotten joint score-12 in patients after ACL reconstruction

BACKGROUND The forgotten joint score-12 (FJS-12), used to measure postoperative joint awareness, has been extensively validated to assess outcomes after arthroplasty, however the new score has never been validated in evaluating anterior cruciate ligament (ACL) reconstruction. The purpose of our study was to validate the FJS-12 versus the knee injury and osteoarthritis outcome score (KOOS) for patients who have undergone ACL reconstruction. METHODS All patients who had undergone ACL reconstruction with the same arthroscopic surgical technique at our institution between 2011 and 2014 (medium-term follow-up group (M-FU)) or between 2000 and 2005 (long-term follow-up group (L-FU)) were considered for inclusion in the study. To analyze unidimensionality of the FJS-12, we calculated Cronbachs alpha, item-total correlations and conducted an exploratory principal component factor analysis. To assess convergent validity, we calculated Spearman correlation coefficients for the FJS-12 and its comparable scales. RESULTS We analyzed 58 patients of the M-FU (mean follow-up 31.5 (SD13.4) months, range 12-54), and 58 patients of the L-FU (mean follow-up 139 (SD15.2) months, range 120-179). The FJS-12 showed high internal consistency (Cronbachs alpha=0.95). Ceiling effects were considerably lower for the FJS-12 (M-FU 12.1%, L-FU 15.5%) compared with the KOOS subscales (M-FU 5.2-37.9%; L-FU 13.8-55.2%) and WOMAC subscales (M-FU 37.9-62.1%; L-FU 44.8-60.3%). CONCLUSIONS The FJS-12 is a valid measurement tool to evaluate outcomes of ACL reconstruction. This study extends the possibilities of measuring joint awareness as a patient-reported outcome parameter from joint arthroplasty to ACL reconstruction.

Haptic assessment of bone quality in orthopedic surgery: no consensus but perspective for high training potential

The ability to intraoperatively assess bone quality is important for orthopedic surgeons because bone quality might be a decisive factor for treatment strategy.1 However, this ability is usually not systematically taught in the surgical curriculum. Orthopedic residents learn about the physical property of the bone early in their formation. They also learn about the radiological assessment of bone quality by computed tomography, measuring bone mineral density2 or by measuring the cortical thickness of the proximal humeral diaphysis in standard anterior-posterior X-rays or the deltoid tuberosity index.3,4 However, these preoperative radiological measurements are indirect assessments of bone quality that cannot dispense orthopedic surgeons from direct intraoperative assessment. The bone quality of humeral metaphysis is crucial for the use of new stemless shoulder arthroplasty systems because the humeral component could loosen early (primary nonbonding) if press-fit fixation in the cancellous bone is not reliable.5 The decision if the bone shows “adequate” quality for using a particular implant design relies on the intraoperative judgment of the surgeon and depends on his manual skill and experience. Tools for intraoperative assessment of bone quality have been developed6,7 but are complicated and not readily available in a routine clinical setting, whereas simple tactile (haptic) assessment by the surgeon can easily be performed. In surgical courses, young residents learn mainly operative techniques, especially the handling of surgical instruments and implants. Interestingly, however, assessment of bone quality by haptic perception is not systematically taught in the clinical training of orthopedics residents. It seems that surgeons individually develop a “feeling” about what is “adequate bone quality” by trial and error. However, we do not know if this feeling is the same for all orthopedic surgeons. We believe that even in highly specialized and more technological medicine simple manual testing and haptic assessment remains crucial and might get lost in the contemporary education of young surgeons. Following questions arise: Can haptic assessment of bone quality regarding load-bearing capacity be standardized and systematically be taught and trained? The purpose of this perspective, therefore, is to discuss the intraoperative haptic assessment of bone quality and to evaluate the precision of the assessment, its training and its learning process. This might open new questions and further directions in surgical education.