Minimally invasive lateral plating for diaphyseal fractures with extension into the proximal humerus and its implications for the deltoid muscle and its distal insertion: functional analysis and MR-imaging.

BACKGROUND: In minimally invasive lateral plate osteosynthesis of the humerus (MILPOH) the plate is introduced through a deltoid split proximally and advanced through the central portion of the deltoid insertion and between bone and brachial muscle to the distal aspect of the humerus. The fracture is then indirectly reduced and bridged by the plate. Whereas it has been shown that the strong anterior and posterior parts of the distal deltoid insertion remain intact with this maneuver, its impact on deltoid muscle strength and muscular morphology remains unclear. It was the aim of this study to evaluate deltoid muscle function and MR-morphology of the deltoid muscle and its distal insertion after MILPOH. METHODS: Six patients (median age 63 years, range 52-69 years, f/m 5/1) who had undergone MILPOH for diaphyseal humeral fractures extending into the proximal metaphysis and head (AO 12B/C(i)) between 08/2017 and 08/2020 were included. Functional testing was performed for the injured and uninjured extremity including strength measurements for 30/60/90° shoulder abduction and flexion at least one year postoperatively. Constant-Murley-Score (CMS) including an age-and gender-adjusted version, were obtained and compared to the uninjured side. Oxford Shoulder Score (OSS) and the Disability of the Arm, Shoulder and Hand (DASH) questionnaire were acquired for the affected extremity. Quality of life was measured using the EQ visual analogue scale (EQ-5D-5 L VAS). MR imaging was performed for both shoulders accordingly at the time of follow-up to assess the integrity of the distal insertion, muscle mass and fatty degeneration of the deltoid muscle. Muscle mass was determined by measuring the area of the deltoid muscle on the axial MR image at the height of the center of the humeral head. RESULTS: Median follow-up was 29 months (range 12-48 months). Median difference of abduction strength after MILPOH was + 13% for 30°, 0% for 60° and - 22% for 90°. For flexion, the difference to the uninjured side was measured 5% for 30°, -7% for 60° and - 12% for 90°. Median CMS was 75 (66-82) for the operated extremity compared to 82 (77-90) for the uninjured side. Age- and gender-adapted CMS was calculated 88 (79-99) vs. 96 (89-107). Median OSS was 47 (40-48). DASH was 26 (15-36). EQ-5D-5 L VAS ranged from 81 to 95 with a median of 90. The median difference of the deltoid muscle area on MRI was 2% (-21% to + 53%) compared to the uninjured side. No fatty degeneration of the deltoid muscle was observed. The weaker central part of the distal deltoid insertion was exclusively perforated by the plate, leaving the strong anterior and posterior parts of the insertion intact in all patients. CONCLUSIONS: MILPOH was associated with good functional and subjective outcome. Minor impairment of abduction strength was observed with increasing abduction angles. The reason for this impairment is unclear since MILPOH did not affect the structural quality of the deltoid muscle and the integrity of the strong anterior and posterior parts of its insertion remained intact. TRIAL REGISTRATION: 26/05/2023: ISRCTN51786146.

The levels of vancomycin in the blood and the wound after the local treatment of bone and soft-tissue infection with antibiotic-loaded calcium sulphate as carrier material.

AIMS: Calcium sulphate (CaSO4) is a resorbable material that can be used simultaneously as filler of a dead space and as a carrier for the local application of antibiotics. Our aim was to describe the systemic exposure and the wound fluid concentrations of vancomycin in patients treated with vancomycin-loaded CaSO4 as an adjunct to the routine therapy of bone and joint infections. PATIENTS AND METHODS: A total of 680 post-operative blood and 233 wound fluid samples were available for analysis from 94 implantations performed in 87 patients for various infective indications. Up to 6 g of vancomycin were used. Non-compartmental pharmacokinetic analysis was performed on the data from 37 patients treated for an infection of the hip. RESULTS: The overall systemic exposure remained within a safe range, even in patients with post-operative renal failure, none requiring removal of the pellets. Local concentrations were approximately ten times higher than with polymethylmethacrylate (PMMA) as a carrier, but remained below reported cell toxicity thresholds. Decreasing concentrations in wound fluid were observed over several weeks, but remained above the common minimum inhibitory concentrations for Staphylococcus up to three months post-operatively. CONCLUSION: This study provides the first pharmacokinetic description of the local application of vancomycin with CaSO4 as a carrier, documenting slow release, systemic safety and a release profile far more interesting than from PMMA. In particular, considering in vitro data, concentrations of vancomycin active against staphylococcal biofilm were seen for several weeks. Cite this article: Bone Joint J 2017;99-B:1537-44.

Reduction Techniques for Trochantericand Subtrochanteric Fractures of the Femur: a Practical Guide.

Trochanteric intramedullary nailing has gained widespread acceptance and popularity among orthopedic trauma surgeons. Whereas some simple fracture patterns are easily reduced and nailed, others may present a major challenge for the surgeon. Anatomical reduction and optimal placement of the intramedullary implants are the most important factors for fracture healing and good functional outcome. Closed anatomical reduction is to be achieved before the nail is inserted. However, especially in inter- and subtrochanteric fractures, a limited open or even open reduction technique may be necessary to achieve an adequate reduction. This article focuses on a structured and practical approach to various reduction techniques based on characteristic displacement patterns. The authors describe in detail their favored reduction techniques with tips and tricks for problem-solving. Furthermore, a non-systematic review of the current literature is provided with a critical appraisal of the described techniques and alternative methods. Key words: trochanteric, subtrochanteric femur, fracture, reduction, cephalomedullary nail.

Cost analysis of fresh-frozen femoral head allografts: is it worthwhile to run a bone bank?

To assess the sustainability of our institutional bone bank, we calculated the final product cost of fresh-frozen femoral head allografts and compared these costs with the use of commercial alternatives. Between 2007 and 2010 all quantifiable costs associated with allograft donor screening, harvesting, storage, and administration of femoral head allografts retrieved from patients undergoing elective hip replacement were analysed. From 290 femoral head allografts harvested and stored as full (complete) head specimens or as two halves, 101 had to be withdrawn. In total, 104 full and 75 half heads were implanted in 152 recipients. The calculated final product costs were €1367 per full head. Compared with the use of commercially available processed allografts, a saving of at least €43 119 was realised over four-years (€10 780 per year) resulting in a cost-effective intervention at our institution. Assuming a price of between €1672 and €2149 per commercially purchased allograft, breakeven analysis revealed that implanting between 34 and 63 allografts per year equated to the total cost of bone banking.

CT metal artefact reduction for internal fixation of the proximal humerus: value of mono-energetic extrapolation from dual-energy and iterative reconstructions.

AIM: To assess the value of dual-energy computed tomography (DECT) and an iterative frequency split-normalized metal artefact reduction (IFS-MAR) algorithm compared to filtered back projections (FBP) from single-energy CT (SECT) for artefact reduction in internally fixated humeral fractures. MATERIALS AND METHODS: Six internally fixated cadaveric humeri were examined using SECT and DECT. Data were reconstructed using FBP, IFS-MAR, and mono-energetic DECT extrapolations. Image analysis included radiodensity values and qualitative evaluation of artefacts, image quality, and level of confidence for localizing screw tips. RESULTS: Radiodensity values of streak artefacts were significantly different (p < 0.05) between FBP (-104 ± 222) and IFS-MAR (73 ± 122), and between FBP and DECT (32 ± 151), without differences between IFS-MAR and DECT (p < 0.553). Compared to FBP, qualitative artefacts were significantly reduced using IFS-MAR (p < 0.001) and DECT (p < 0.05), without significant differences between IFS-MAR and DECT (p < 0.219). Image quality significantly (p = 0.016) improved for IFS-MAR and DECT compared to FBP, without significant differences between IFS-MAR and DECT (p < 0.553). The level of confidence for screw tip localization was assessed as best for DECT in all cases. CONCLUSION: Both IFS-MAR in SECT and mono-energetic DECT produce improved image quality and a reduction of metal artefacts. Screw tip positions can be most confidently assessed using DECT.