Reversed total shoulder arthroplasty for rotator cuff arthropathy is associated with increased scapulothoracic motion: A longitudinal two-year kinematic study.

BACKGROUND: Reversed total shoulder arthroplasty (RTSA) is a standard surgical procedure for the treatment of rotator cuff tear arthropathy (CTA), aimed at restoring active arm elevation. Shoulder elevation relies on both scapulothroacic (ST) and glenohumeral (GH) motion, but RTSA computer planning primarily focuses on the GH joint due to challenges in visualizing scapulothroacic (ST) motion. RESEARCH QUESTION: Does the scapulohumeral rhythm, by means of the relative contributions of ST rotation and GH elevation per degree of arm elevation, in a longitudinal setting for up to two years postoperatively after RTSA for CTA change? METHODS: In a prospective longitudinal study, shoulder kinematics were studied in 20 patients (22 shoulders) before and at three, six, 12, and 24 months after RTSA implantation for CTA. Skin markers were tracked using 3D motion analysis. The relative ST and GH contributions per degree of arm elevation were assessed and were compared using statistical non-parametric mapping with Bayesian inference. RESULTS: Mean arm elevation was 89 ± 33° preoperatively, 135 ± 28° at 3 months, 161 ± 20° at 6 months, 169 ± 18° at 12 months, and 165 ± 19° at 24 months. Between 48-66°, 62-93°, 53-94°, 60-97° and 72-104° of arm elevation at the measurement time points pre, 3-months, 6-months, 12-months and 24-months postoperatively, respectively, the ST rotation had a significantly greater contribution to arm elevation compared to GH elevation; a pattern that was not found in controls. SIGNIFICANCE: While RTSA successfully restored active arm elevation through improved GH and ST motion, the scapulohumeral rhythm exhibited a consistent pattern up to two years postoperatively, resembling the preoperative state. In the midrange of motion, ST rotation dominated over GH elevation, potentially contributing to muscular fatigue and explaining the documented decline in functional outcomes over time after RTSA. The findings highlight the importance of incorporating ST kinematics into modern computer planning for RTSA.

The effects of length and width of the stem on proximal humerus stress shielding in uncemented primary reverse total shoulder arthroplasty.

INTRODUCTION: To preserve humeral bone during RTSA, stems have been made shorter and cement avoided whenever possible. However, with the increased use of uncemented RTSA, a phenomenon comparable to the stress shielding of the hip has been described for the proximal humerus. The aim of this study was to investigate the influence of stem length and width on proximal humeral bone resorption after primary uncemented RTSA. MATERIALS AND METHODS: The prospective shoulder arthroplasty database of our institution was reviewed for all primary uncemented RTSAs from 2017 to 2020 in osteoarthritis and cuff tear arthropathy cases with > 2-year follow-up. We compared the clinical and the radiographic 2-year outcome of the short and standard length stems of the same prosthesis design. This allowed us to assess the effects of stem length and width with regard to stress shielding. Furthermore, we defined a cut-off value for the filling ratios to prevent stress shielding. RESULTS: Fifty patients were included in the analysis, nineteen were in the short stem group (SHORT) and thirty-one in the standard stem group (STANDARD). After 2 years, SHORT showed a relative Constant Score of 91.8% and STANDARD of 98.3% (p = 0.256). Stress shielding was found in 4 patients (21%) in SHORT and in 16 patients (52%) in STANDARD (p = 0.03); it occurred more frequently in patients with higher humeral filling ratios (p < 0.05). The calculated cut-off to prevent stress shielding was 0.7 (± 0.03) for the metaphyseal and distal filling ratio. CONCLUSION: While short and standard stems for RTSA have good results after 2 years, we found a significant negative effect of higher length and width of the stem with regard to stress shielding. Even though the clinical effects of stress shielding have to be assessed, short stems should be chosen with a filling ratio at the metaphyseal and distal position below 0.7. LEVEL OF EVIDENCE (A RETROSPECTIVE CASE-CONTROL STUDY): III.

Blunt rupture of the biceps brachii muscle - The "parachute injury" in a wake surfer - A case report.

Case: A 40-year-old man fell while wake surfing and his left arm got tangled in the rope. This caused a closed complete rupture of the M. biceps brachii. A primary muscle suture led to unrestricted function and excellent patient satisfaction after two years. Conclusions: The mentioned muscle rupture is a rare injury mainly described for paratroopers. As it has also been described for wakeboarding, this is the first description in wake surfing. Whereas in wakeboarding mainly experts are at risk during jumps, in wake surfing beginners are in danger and must be advised accordingly. Generally, the muscle suture leads to excellent function in these patients.

Cemented vs. uncemented reverse total shoulder arthroplasty for the primary treatment of proximal humerus fractures in the elderly-a retrospective case-control study.

BACKGROUND: Uncemented reverse total shoulder arthroplasty (RTSA) for the primary treatment of proximal humerus fractures (PHF) in elderly patients was introduced at our institution in 2017. Recent reports have raised concerns about increased rates of early bone resorption at the proximal humerus with uncemented fracture stems. The aim of this study was to find out whether there was any difference in functional or radiographic outcomes between cemented and uncemented RTSA for PHF. METHODS: Seventeen consecutive patients who underwent uncemented RTSA (group nC) in 2017 and 2018 were age and sex matched (propensity score matching 1:2) to 34 patients with cemented RTSA implanted between 2011 and 2016 (group C) for the primary treatment of PHF. These two groups were compared in terms of clinical and radiographic outcomes at 2 years after the index surgery. RESULTS: The mean bone quality was low in both groups: in group nC the deltoid tuberosity index (DTI) was 1.43 (1.22-1.72) and in group C 1.42 (1.22-1.67). At the final 2 year follow-up, the relative CS was 98.3% (71-118) in group nC and 97.9% (36-125) in group C (p = 0.927); the absolute CS was 70.2 (49-89) in group nC and 68.0 (30-94) in group C (p = 0.509). Lucent lines at the humeral site were seen in 8 cases (47%) in group nC and in 13 cases (38%) in group C (p = 0.056). Compared to 3% in group C, all patients in group nC showed at least grade 1 and 65% showed grade 3 bone resorption at the proximal humerus (p < 0.001). CONCLUSION: Compared to cemented RTSA bone resorption at the proximal humerus was significantly more frequent in patients with uncemented RTSA for PHF. So far, this is rather a radiographic than a clinical finding, because both groups showed very satisfying functional outcomes and low revision rates at the 2 year follow-up. LEVEL OF EVIDENCE III: A retrospective case-control study.

Osteochondral Shearing Fracture of the Humeral Head Associated with Traumatic Anterior Shoulder Dislocation: A Case Report.

CASE: Osteochondral shearing fracture of the humeral head after an anterior shoulder dislocation is a condition that has rarely been reported in literature. We report a case of a large posteriorly located fragment of such a fracture in a 23-year-old man. We performed open reduction and internal fixation with resorbable pins through a deltopectoral approach and subscapularis tenotomy. CONCLUSION: In our case of a large osteochondral fracture of the posterior humeral head, treatment by open reduction and internal fixation showed an excellent radiographic result at 1 year and clinical result up to 5 years postoperatively.

Outcomes of Management of Proximal Humeral Fractures with Patient-Specific, Evidence-Based Treatment Algorithms.

BACKGROUND: Previous studies have identified risk factors for different types of treatment of proximal humeral fracture (PHF) and allowed the development of a patient-specific, evidence-based treatment algorithm with the potential of improving overall outcomes and reducing complications. The purpose of this study was to evaluate the results and complications of treating PHF using this algorithmic approach. METHODS: All patients with isolated PHF between 2014 and 2017 were included and prospectively followed. The initial treatment algorithm (Version 1 [V1]) based on patients' functional needs, bone quality, and type of fracture was refined after 2 years (Version 2 [V2]). Adherence to protocol, clinical outcomes, and complications were analyzed at a 1-year follow-up. RESULTS: The study included 334 patients (mean age, 66 years; 68% female): 226 were treated nonoperatively; 65, with open reduction and internal fixation (ORIF); 39, with reverse total shoulder arthroplasty (RTSA); and 4, with hemiarthroplasty. At 1 year, the preinjury EuroQol 5-Dimension (EQ-5D) values were regained (0.88 and 0.89, respectively) and the mean relative Constant Score (CS) and Subjective Shoulder Value (SSV) (and standard deviation [SD]) were 96% ± 21% and 85% ± 16%. Overall complications and revision rates were 19% and 13%. Treatment conforming to the algorithm outperformed non-conforming treatment with respect to relative CS (97% versus 88%, p = 0.016), complication rates (16.3% versus 30.8%, p = 0.014), and revision rates (10.6% versus 26.9%, p < 0.001). CONCLUSIONS: Treating PHF using a patient-specific, evidence-based algorithm restored preinjury quality of life as measured with the EQ-5D and approximately 90% normal shoulders as measured with the relative CS and the SSV. Adherence to the treatment algorithm was associated with significantly better clinical outcomes and substantially reduced complication and revision rates. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

How Do Scapulothoracic Kinematics During Shoulder Elevation Differ Between Adults With and Without Rotator Cuff Arthropathy?

BACKGROUND: Rotator cuff arthropathy with loss of active arm elevation can be successfully treated with nonanatomic reverse total shoulder arthroplasty to restore active elevation. Shoulder kinematics in this context predominantly focus on glenohumeral motion, neglecting scapular motion, although both substantially contribute to global shoulder motion. Because scapular kinematics are difficult to assess clinically and in the laboratory, they are not well understood and therefore are often reduced to glenohumeral models with a static scapula. QUESTIONS/PURPOSES: (1) Does the scapulohumeral rhythm (scapular rotation/glenohumeral elevation ratio) change during arm elevation? (2) Is there any scapular motion before arm elevation becomes clinically visible? (3) How do scapulothoracic kinematics during shoulder elevation differ between adults with and without rotator cuff arthropathy? METHODS: This was a comparative kinematics study of 20 young adult volunteers (reference group) without rotator cuff impairment (seven females, 13 males; mean age: 27 ± 3.5 years) and 20 patients (22 shoulders) with cuff tear arthropathy (10 females, 10 males; mean age: 74 ± 6.2 years). We used a three-dimensional (3-D) motion analysis system from Vicom with eight high-speed infrared cameras (frame rate 200 Hz) and 25 skin markers. Kinematics were studied for scapulothoracic and glenohumeral movements using the Upper Limb Evaluation in Movement Analysis (ULEMA) open-source model. The main motion studied was active arm elevation in the scapular plane. After data cleaning, modeling, and normalization, changes of scapulohumeral rhythm and scapular motion at the beginning of arm elevation were analyzed qualitatively, and statistical parametric mapping was applied to study the difference in scapulothoracic kinematics between adults with and without rotator cuff arthropathy. RESULTS: The scapular rhythm changes continuously during elevation. Whereas in people without rotator cuff arthropathy, a homogenous proportional relative angular contribution between 85° and 120° could be observed, this regular pattern was disturbed in patients with rotator cuff arthropathy. We observed medial scapular rotation before arm elevation became visible, followed by low lateral or even medial scapular rotation (approximately up to 25°) at the beginning of arm elevation. Patients with rotator cuff arthropathy exhibited more scapulothoracic motion between 50° and 93° of elevation than the reference group. CONCLUSIONS: Our study introduces a double-normalized data analysis that allows for a more detailed assessment of complex scapular kinematics in a noninvasive way. Scapulothoracic motion is more complex than previously reported, especially in patients with rotator cuff arthropathy. The scapulohumeral rhythm changes dynamically throughout arm elevation. There is counter-directed scapular rotation because of muscular engagement before clinically visible arm elevation. Compared with the homogenous shoulder kinematics in the reference group, patients with rotator cuff arthropathy show a different pattern with predominantly scapular motion in the range between 50° and 93° of arm elevation. CLINICAL RELEVANCE: The findings of this study suggest that there is a specific pattern of scapular motion during arm elevation in patients with rotator cuff arthropathy. Our study introduces a new noninvasive method that allows for simultaneous analysis of glenohumeral and scapular kinematics. This will enable to investigators explore whether active arm elevation and the physiological motion pattern can be restored after, for example, reverse total shoulder arthroplasty despite a nonanatomic prosthesis configuration.

Is serial radiological evaluation of one-part proximal humeral fractures necessary?

AIMS: In order to determine whether and for whom serial radiological evaluation is necessary in one-part proximal humerus fractures, we set out to describe the clinical history and predictors of secondary displacement in patients sustaining these injuries. PATIENTS AND METHODS: Between January 2014 and April 2016, all patients with an isolated, nonoperatively treated one-part proximal humerus fracture were prospectively followed up. Clinical and radiological evaluation took place at less than two, six, 12, and 52 weeks. Fracture configuration, bone quality, and comminution were determined on the initial radiographs. Fracture healing, secondary displacement, and treatment changes were recorded during follow-up. RESULTS: In 100 patients (59 female, 41 male; mean age 57 years), 91 of the fractures (91%) remained stable. In five of nine patients (55%) with secondary displacement, surgery was recommended. Comminution, present in 23 patients (23%), was identified as a predictor of secondary displacement (p < 0.001). Patients' age, sex, fracture configuration, and bone quality were not associated with secondary displacement (p ≥ 0.438). Nonoperative treatment resulted in a mean absolute Constant score (CS) of 80 (49 to 98), relative CS of 101% (63% to 138%), median subjective shoulder value of 95% (interquartile range (IQR) 90% to 100%), and median EuroQol five-dimensional questionnaire score of 0.89 (IQR 0.80 to 1.00) with bone union in all cases at one-year follow-up. CONCLUSION: Radiological re-evaluation was only necessary in patients presenting with comminution and may be redundant for 77% of patients with one-part proximal humerus fractures. Nonoperative treatment of one-part proximal humerus fractures remains the mainstay of treatment with a low rate of secondary surgery, a high union rate, and good clinical results. Cite this article: Bone Joint J 2019;101-B:1307-1312.

Evidence-based algorithm to treat patients with proximal humerus fractures-a prospective study with early clinical and overall performance results.

BACKGROUND: On the basis of patients' demands, bone quality, and fracture type, we developed an evidence-based treatment algorithm for proximal humerus fractures (PHF) that includes all treatment modalities from open reduction and internal fixation, hemiprosthesis, to reverse total shoulder arthroplasty. This study was done to assess its feasibility and early clinical outcome. MATERIALS AND METHODS: Patients with isolated PHF in 2014 and 2015 were included in this prospective study. The quality of life (EQ-5D) and the level of autonomy before injury were recorded. The fractures were classified and local bone quality was measured. When possible, patients were treated according to the algorithm. Radiographic and clinical follow-up-Constant score, subjective shoulder value, and EQ-5D-took place after 3 months and 1 year. The rate of unplanned surgery was analyzed. RESULTS: A total of 192 patients (mean age 66 years; 58 male, 134 female) were included. Of these, 160 (83%) were treated according to the algorithm. In total, 132 patients were treated conservatively, 36 with open reduction and internal fixation and 24 with reverse total shoulder arthroplasty or hemiarthroplasty. Generally, the mean EQ-5D before trauma and 1 year after treatment was equal to 0.88 to 0.9 points. After 1 year, the overall mean relative Constant score was 95% and mean subjective shoulder value 84%. Unplanned surgery was necessary in 21 patients. CONCLUSION: This comprehensive algorithm is designed as a noncompulsory treatment guideline for PHF, which prioritize the patient's demands and biology. The high adherence proves that it is a helpful tool for decision making. Furthermore, this algorithm leads to very satisfying overall results with low complication and revision rates.

Early Arthroscopic Repair of Acute Traumatic Massive Rotator Cuff Tears Leads to Reliable Reversal of Pseudoparesis: Clinical and Radiographic Outcome.

PURPOSE: It was the aim of this study to analyze the clinical and radiographic outcome after early arthroscopic repair regardless of the age of patients. METHODS: Patients with massive traumatic cuff tear and clinical pseudoparesis for forward elevation treated by subsequent early arthroscopic repair from 2011 until 2014 were included in this retrospective study. Exclusion criteria were Goutallier grade ≥3 fatty infiltration and prior shoulder problems or surgery. Magnetic resonance imaging (MRI), radiographs, and functional assessments were performed preoperatively and at follow-up. RESULTS: A total of 21 patients (male/female 15/6; age range: 30-83) were included. Preoperative MRI showed complete 2 tendon tears in 7 patients, 3 tendon tears in 13 patients and all tendons ruptured in one patient. All patients had full passive range of motion and the mean active elevation was 35.7° (range: 0°-60°). Nine patients also had a pseudoparesis for external rotation (mean: 10°, range: -30° to 40°). The mean delay until surgery was 33 days (range: 13-60). At follow-up (mean: 39 months, range: 24-60) all patients showed reversal of pseudoparesis, mean elevation of 165.2° (range: 110°-180°) and mean external rotation of 49.3° (range: -20° to 80°). The mean Constant score was 82 points (range: 56-95), and the mean subjective shoulder value was 93% (range: 50-100). The overall retear rate was 20% (n = 4). Fatty infiltration increased at least 1 grade in patients who had a retear and in 56% of patients (n = 9) without retear. Age was not a predictor for retear. CONCLUSIONS: This study shows that early arthroscopic repair of traumatic massive RCT with pseudoparesis may lead to successful results regardless of patients' age. A complete restoration of the function can be expected even in patients with retear. The retear rate is low and the increase of fatty infiltration minimal. LEVEL OF EVIDENCE: Level IV, case series.

Blackburne-Peel ratio predicts patients' outcomes after total knee arthroplasty.

PURPOSE: Alterations in patellar height and posterior tibial slope (PTS) are frequently measured radiographic parameters associated with postoperative impairments after total knee arthroplasty (TKA). Few studies correlate the clinical outcome of TKA with the radiological indices. Both the modified Insall-Salvati ratio (mISR) and the Blackburne-Peel ratio (BPR) were hypothesised to correlate with the clinical outcome after TKA. METHODS: A total of 282 computer navigated primary LCS®-TKAs, implanted in our institution from 2008 to 2012, were included. Data (ROM, FJS-12, WOMAC, and revision surgery) were collected independently and prospectively. Patellar height (mISR, BPR), joint-line position, and PTS were measured on pre- and postoperative radiographs. Bivariate and multiple regression analyses were performed. RESULTS: Mean mISR (1.5-1.4) and BPR (0.8-0.6) decreased from preoperatively to 1 year follow-up. Mean joint-line shift in a cranial direction was 2 mm after TKA implantation. Analysis of dichotomous variables (presence of PB and PPB or not) only showed significantly lower flexion in patients with PPB (p < 0.001). However, multiple regression revealed that BPR was a significant positive independent predictor for FJS-12 (p = 0.016) and flexion (p < 0.001) at 1 year follow-up. Postoperative PTS (p < 0.01) and initial patella height (p < 0.001) were both predictive for BPR at follow-up, while the joint-line height was not. CONCLUSIONS: The BPR is a useful and reliable radiographic parameter to predict patient outcomes 1 year after primary navigated TKA. Lowering the BPR should be avoided, as this may lead to significant restrictions in terms of ROM and PROMs. LEVEL OF EVIDENCE: Level 3.

Radiocapitellar arthroplasty: a consecutive case series with 2 to 6 years' follow-up.

BACKGROUND: The aim of this study was to analyze indications, outcomes, and complications in patients treated with radiocapitellar arthroplasty. METHODS: This prospective analysis of clinical and radiographic results included 16 elbows in 15 patients. RESULTS: This study included 4 men and 11 women (mean age, 51.9 years; age range, 32-65 years). The mean follow-up period was 3.4 years (range, 2-6 years). The indications were post-traumatic (n = 10) and primary radiohumeral osteoarthritis (n = 6). A mean of 2 surgical procedures (range, 0-4) had been performed before radiocapitellar arthroplasty. The mean Mayo Elbow Performance Score significantly improved from 46 points to 85 points (P < .01). The arc of motion improved from 106° to 117° (P = .27). Radiographic ulnohumeral degeneration progressed in 40% of cases but was not symptomatic in any. Subsequent surgery was required in 5 elbows (31%). Revision of the radial head component was necessary in 4 patients (25%). In 3 patients this was a result of loosening of the stem. The radial component was subsequently removed because of persistent pain in 1. Radiographic loosening not requiring revision was found in 2 patients. CONCLUSION: The overall Mayo Elbow Performance Score was good to excellent after radiocapitellar arthroplasty. Both the revision and reoperation rates were high, and one should consider this before performing this procedure. Loosening of the radial head component was a problem. An improved fixation technique or an adaptation of the design is needed before this type of surgery can be recommended as a standard procedure.

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.

Evaluation of ninety-six periprosthetic hip joint infections seen within five consecutive years.

Periprosthetic hip joint infections (PHJI) are severe complications. In 2003 Zimmerli published a well-noted treatment algorithm for PHJI. The aim of this study is to evaluate outcome, analyze the applied treatment regimen and compare it to the proposed algorithm. We evaluated the outcome of 96 PHJI treated at our institution between 2008 and 2012 and analysed adherence to the algorithm and outcome in coherence with the algorithm. The operations performed were irrigation and debridement with exchange of mobile parts (45%), two-stage exchange (36%), one-stage exchange (12%) and permanent explantation (7%). 47% were acute infections, 53% were chronic. Staphylococcus aureus was the most common pathogen. The overall success rate was 88%. In 12% of the cases the chosen operation didn't follow the algorithm. Of these only 10% was successfully treated with the primary operation. We find that the algorithm proposed by Zimmerli is a useful tool and easy to translate into clinical practice. When followed it yields a high success rate.

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.

Prophylactic adjacent-segment vertebroplasty following kyphoplasty for a single osteoporotic vertebral fracture and the risk of adjacent fractures: a retrospective study and clinical experience.

OBJECTIVE This study investigated the benefit of prophylactic vertebroplasty of the adjacent vertebrae in single-segment osteoporotic vertebral body fractures treated with kyphoplasty. METHODS All patients treated with kyphoplasty for osteoporotic single-segment fractures between January 2007 and August 2012 were included in this retrospective study. The patients received either kyphoplasty alone (kyphoplasty group) or kyphoplasty with additional vertebroplasty of the adjacent segment (vertebroplasty group). The segmental kyphosis with the rate of adjacent-segment fractures (ASFs) and remote fractures were studied on plain lateral radiographs preoperatively, postoperatively, at 3 months, and at final follow-up. RESULTS Thirty-seven (82%) of a possible 45 patients were included for the analysis, with a mean follow-up of 16 months (range 3-54 months). The study population included 31 women, and the mean age of the total patient population was 72 years old (range 53-86 years). In 21 patients (57%), the fracture was in the thoracolumbar junction. Eighteen patients were treated with additional vertebroplasty and 19 with kyphoplasty only. The segmental kyphosis increased in both groups at final follow-up. A fracture through the primary treated vertebra (kyphoplasty) was found in 4 (22%) of the vertebroplasty group and in 3 (16%) of the kyphoplasty group (p = 0.6). An ASF was found in 50% (n = 9) of the vertebroplasty group and in 16% (n = 3) of the kyphoplasty group (p = 0.03). Remote fractures occurred in 1 patient in each group (p = 1.0). CONCLUSIONS Prophylactic vertebroplasty of the adjacent vertebra in patients with single-segment osteoporotic fractures as performed in this study did not decrease the rate of adjacent fractures. Based on these retrospective data, the possible benefits of prophylactic vertebroplasty do not compensate for the possible risks of an additional cement augmentation.

A new stem extractor with specific multigrip pliers for revision hip arthroplasty - a biomechanical investigation.

INTRODUCTION: It was the aim of this biomechanical study to test a new extractor with 2 specific multigrip pliers on different stem designs and to compare it to a commonly used prefabricated one (UnMod). METHODS: The new extractor comprises 2 specific multigrip pliers, 1 neck-pliers and 1 shoulder-pliers. The tests were performed on a tapered and a nontapered neck stem. They were fixed in specific moulds allowing torque adjustability. The first endpoint was maximum grip with the extractors being tested up to 70 hits or failure (pliers off) in maximally fixed stems. The second endpoint was hits/attempts until stem extraction or failure (pliers off > than 5 times) in moderately fixed stems. RESULTS: The best grip on the tapered neck was achieved by the neck-pliers without failure, whereas the others failed consistently (shoulder-pliers: mean 42.9 hits, SD: 3.5/UnMod: 40.1, SD: 5.4; p<0.01). The shoulder-pliers had the best grip on the nontapered neck withstanding more hits (11.9, SD: 1.9) than the others (neck-pliers: 4.8, SD: 1.7/UnMod: 2.8, SD 1.0; p<0.01). None of the devices failed to extract the tapered neck (UnMod best: 4, SD: 1.3). The shoulder-pliers were able to extract the nontapered neck in 60% of the tests, whereas the others failed 100%. CONCLUSIONS: The new extractor with specific pliers for neck/shoulder grip seems to be a valuable tool for stem extraction in revision hip arthroplasty. Compared to UnMod, the neck-pliers showed better grip on the tapered neck and the shoulder-pliers performed the best on the nontapered neck.

Biomechanical properties of a posterior fully threaded positioning screw for cannulated screw fixation of displaced neck of femur fractures.

OBJECTIVES: Displaced intracapsular neck of femur fractures (NOF) in younger patients are usually fixed with partially-threaded cannulated screws. However posterior comminution may lead to construct failure. We hypothesised that a posterior fully threaded positioning screw would enhance stability. METHODS: A total of 16 left composite femora (Sawbone) were used for testing. To mimic a subcapital fracture with posterior comminution, a subcaptial osteotomy was performed and a posterior wedge was resected from the neck. Group A (n=8) was fixed using 3 partially threaded cancellous screws. In Group B (n=8), a fully threaded positioning screw instead of a partially threaded was used posteriorly. The specimens were tested for bending (antero-posterior=A-P) and axial stiffness. Finally, they were axially loaded up to failure or up to 10,000 cycles and the final displacement was measured at the site of the resected neck. More than 5mm of displacement was considered as a failure of the construct. RESULTS: Group B showed significantly higher average A-P stiffness (665±17N/mm compared to 414±41N/mm, p=0.0004); whereas axial stiffness did not significantly differ between the two groups (p=0.301). In Group B, the mean final displacement after cyclic axial loading was 0.51±0.13mm and none of the specimens failed, whereas 7 of 8 constructs failed in Group A (p=0.001). CONCLUSIONS: This biomechanical study points out a potential benefit of replacing the posterior partially threaded cancellous screw with a fully threaded positioning screw in subcapital NOF with posterior comminution. The construct with the fully threaded screw significantly improved the A-P stiffness and reduced the collapse of the fracture.