Paolo Baudi

A 3D finite element model for geometrical and mechanical comparison of different supraspinatus repair techniques

BACKGROUND Contact pressure and contact area are among the most important mechanical factors studied to predict the effectiveness of a rotator cuff repair. The suture configurations can strongly affect these factors but are rarely correlated with each other. For example, there is a significant difference between the single-row technique and the transosseous or transosseous-like approaches in terms of footprint contact area coverage. A finite element model-based approach is presented and applied to account for various parameters (eg, suture pretension, geometry of the repair, effect of the sutures, geometry of the lesion) and to compare the efficacy of different repair techniques in covering the original footprint. METHODS The model allows us to evaluate the effect of parameters such as suture configuration and position and suture pretension. The validity of such an approach was assessed in comparing 3 different repair techniques: single row, transosseous equivalent, and double row. RESULTS Results from the application of the models show that the double-row and transosseous-equivalent techniques lead to progressive increase of the contact area compared with the single-row approach, supporting the conclusion that transosseous-equivalent fixation leads to an increase of the contact area and a better distribution of the pressure coverage. CONCLUSION The 3-dimensional finite element model approach allows multiple variables to be assessed singularly, weighing the specific influence. Moreover, the approach presented in this study could be a valid tool to predict and to reproduce different configurations, identifying how to reduce the stress over the tendon and when a repair could be effective or not.

Arthroscopic Rotator Cuff Tear Transosseous Repair System: The Sharc-FT Using the Taylor Stitcher

Transosseous rotator cuff tear repair was first described in 1944. Over the years, it has represented the gold standard for such lesions. Through open and mini-open approaches, as well as the arthroscopic approach, the transosseous repair system represents one of the most reliable surgical techniques from a biological and mechanical perspective. Nevertheless, further improvements are required. This article describes an arthroscopic rotator cuff tear transosseous repair system, developed in collaboration with NCS Lab (Carpi, Italy): the Sharc-FT using the Taylor Stitcher. Our first experience in the clinical application of the arthroscopic technique using the transosseous suture system has shown encouraging clinical outcomes, confirming its efficacy. The patient satisfaction rate was high, and no patient expressed concern about the implant. The complication rate was very low. By improving the suture technique in the treatment of rotator cuff tears, a remarkable increase in the success rate in the treatment of this pathology could be reached; nevertheless, complications such as retears of the rotator cuff still occur.

Gap formation in a transosseous rotator cuff repair as a function of bone quality

BACKGROUND The transosseous approach has been well known for a long time as a valid repair approach. Over time, various criticisms have been raised over this technique principally classifiable in two main categories: technical difficulty and related reproducibility in an arthroscopic environment, and repair stability (in the suture-bone contact area). About cyclic performance, several authors have conceived test setups with the aim of simulating a real environment in dynamic load conditions. The aim of this study was to monitor gap formation in a cyclic test setup. METHODS The performance (measured as gap formation) has been monitored as a function of bone density to verify the effect of the latter. The test blocks have been shaped using sawbones® test bricks (Malmo, Sweden) of different densities, and the following values have been tested: 10, 15, 20, 30 and 40pcf. FINDINGS The comparison has been made between the two groups: traditional transosseous and new approach with an interposed device. Regarding the traditional transosseous approach in a 10-pcf environment, not even the first loading cycle was completed, the whole bone bridge was destroyed in the first loading ramp and no further loading capability was present in the repair. By increasing the block density, the surface damage in the suture-block contact decreased. INTERPRETATION With this work, it has been demonstrated how the traditional transosseous approach is strongly influenced by the bone quality up to the point where, in certain conditions, a safe and reliable repair is not guaranteed.

Morphological study: Ultrastructural aspects of articular cartilage and sub-chondral bone in patients affected by post-traumatic shoulder instability.

Post‐traumatic shoulder instability is a frequent condition in active population, representing one of most disabling pathologies, due to altered balance involving joints. No data are so far available on early ultrastructural osteo‐chondral damages, associated with the onset of invalidating pathologies, like osteoarthritis‐OA. Biopsies of glenoid articular cartilage and sub‐chondral bone were taken from 10 adult patients underwent arthroscopic stabilization. Observations were performed under Transmission Electron Microscopy‐TEM in tangential, arcuate and radial layers of the articular cartilage and in the sub‐chondral bone. In tangential and arcuate layers chondrocytes display normal and very well preserved ultrastructure, probably due to the synovial liquid supply; otherwise, throughout the radial layer (un‐calcified and calcified) chondrocytes show various degrees of degeneration; occasionally, in the radial layer evidences of apoptosis/autophagy were also observed. Concerning sub‐chondral bone, osteocytes next to the calcified cartilage also show signs of degeneration, while osteocytes farther from the osteo‐chondral border display normal ultrastructure, probably due to the bone vascular supply. The ultrastructural features of the osteo‐chondral complex are not age‐dependent. This study represents the first complete ultrastructural investigation of the articular osteo‐chondral complex in shoulder instability, evaluating the state of preservation/viability of both chondrocytes and osteocytes throughout the successive layers of articular cartilage and sub‐chondral bone. Preliminary observations here collected represent the morphological basis for further deepening of pathogenesis related to shoulder instability, enhancing the relationship between cell shape and microenvironment; in particular, they could be useful in understanding if the early surgical treatment in shoulder instability could avoid the onset of OA. Anat Rec, 300:1208–1218, 2017.

Imaging of the Unstable Shoulder

Background: Unstable shoulder can occur in different clinical scenarios with a broad spectrum of symptoms and presentations: first-time (or recurrent) traumatic acute shoulder anterior dislocation or chronic anterior instability after repeated dislocations. Imaging in unstable shoulder is fundamental for choosing the right treatment preventing recurrence. The goal of imaging depends on clinical scenario and patient characteristics. Method: Careful selection and evaluation of the imaging procedures is therefore essential to identify, characterize and quantify the lesions. Proper imaging in unstable shoulder cases is critical to the choice of treatment to prevent recurrence, and to plan surgical intervention. Results: In acute setting, radiographs have to roughly detect and characterize the bone defects present. At about 7 days, it is recommended to perform a MR to demonstrate lesions to labrum and/or ligaments and bone defects: in acute setting, the MRA is not necessary, because of effusion and hemarthrosis that behave as the contrast medium. In recurrence, it is fundamental not only to detect lesions but characterize them for planning the treatment. The first study to do is the MRI (with a magnetic field of at least 1.5 Tesla), and if possible MRA, above all in younger patients. Then, on the basis of the pathologic findings as bipolar lesion or severity of bone defects, CT can be performed. PICO method on 2D or 3D CT is helpful if you need to study a glenoid bone loss, with the “en face view” of glenoid, while a 3D CT reconstruction with the humeral head “en face view” is the gold standard to assess an Hill-Sachs lesion. Conclusion: The clinical diagnoses of anterior shoulder instability can be different and acknowledgement of imaging findings is essential to guide the treatment choice. Imaging features are quite different in chronic than in acute scenario. This requires appropriate indications of many different imaging techniques.

Humeral shaft non-union after intramedullary nailing

BackgroundThe humerus shaft is one of the sites with the largest probability of developing pseudoarthrosis after fracture. We present the results of nine patients with atrophic pseudoarthrosis of humeral shaft treated with angular stability plate associated with allograft and platelet-rich plasma (PRP), after a first treatment with intramedullary nail to correct the fracture.Material and MethodsFrom January 2012 to December 2014, nine patients were treated for atrophic pseudoarthrosis (PSA) of humeral shaft treated previously using intramedullary nail; seven humeral diaphysis fractures were located in the middle–proximal third and two in the middle third. In one case, a reverse shoulder prosthesis implant was associated to treat a co-existent rotator cuff massive lesion. The mean time between injury and treatment of non-union was 32 weeks (min 16–max 180); all patients were evaluated with Constant, DASH and UCLA score.ResultsAt the final follow-up (23.7 months), the mean Dash score was 22.25 pt, the Constant score was 64 pt, and the UCLA score value was 27 pt. The average pain value was 2 for the arm interested and 0 into PSA focus. Radiographic healing was obtained at 7 months.ConclusionsThe humeral shaft non-union is an invalidating problem which affects the daily living. Our treatment with plate, cortical bone graft, and PRP can build a high-stability structure that can help healing and graft integration.

Ultrastructural aspects of articular cartilage and sub- chondral bone in patients affected by post-traumatic shoulder instability: preliminary observations

Post traumatic shoulder instability is a frequent condition in young active popula- tion. Notwithstanding a lot of data have been collected on capsular-legament lesions and gleno-humeral defects, no data are available on early ultrastructural ostheo-condral damages that are known to be highly associated with the onset of invalidating pathologies, like osteoarthritis (OA). Thus, the mechanisms of joint instability and the identification of which components in the articular complex are primarily affected in instability are of clinical significance, particularly in the light of deepening knowledge on the onset/development of OA. In the present study, biopsies of the articular cartilage and sub-chondral bone were taken from 10 patients (aged 26-40) underwent surgery in Policlinico of Modena. The withdrawals were immediately fixed and embedded for Transmission Electron Microscopy (TEM). The observations were per- formed in tangential, arcuate, and radial layers of the articular cartilage as well as in sub-chondral bone. TEM observations showed that chondrocytes in the superficial layers (i.e. tangential and arcuate) display normal and very well preserved ultrastruc- ture, probably due to synovial liquid supply; otherwise, chondrocytes in the radial layer (not only in calcified but also in the un-calcified one) show various degrees of degeneration, with cytoplasm partially coerced and variously-sized vacuoles, both signs of suffering; occasionally, in the radial layer, chondrocytes with morphological signs of apoptosis or autophagy were also observed. As far as sub-chondral bone is concerned, osteocytes next the deeper calcified cartilage (within 80-100 micra from the cement line) also show evidences of degeneration, while osteocytes more dis- tant from the osteo-chondral border display normal ultrastructure probably due to the vascular bone supply. In all patients of the study, the ultrastructural features of osteo-chondral complex are not depending on age. The present study represents the first ultrastructural investigation of the articular osteo-chondral complex in shoulder instability, evaluating the state of preservation/viability of both chondrocytes and osteocytes throughout the successive layers of the articular cartilage and sub-chondral bone. These preliminary observations are the basis to understand if the early surgical treatment in shoulder instability could avoid the onset of OA.