Numerical investigation of patellar instability during knee flexion due to an unbalanced medial retinaculum loading effect.

Background and aim: Healthy patellofemoral (PF) joint mechanics are critical to optimal knee joint function. Patella plays a vital role in distributing quadriceps load during the knee extension. Patellar tracking, not physiological tracking, causes an increase of strains in PF ligaments, peaks of localized stress of soft tissues and articular cartilage and bony parts, and knee pain; these problems lead to complications such as bone abnormalities and osteoarthritis. This research aimed to develop a Finite Element (FE) model to evaluate patellar instability due to the medial retinaculum asymmetric loading effect. Methods: A numerical model of the knee was obtained by matching nuclear magnetic resonance (MRI) for soft tissues and computerized tomography (CT) for bones, carried on a normal adult. Loading setup was chosen by using literature data. The intensity of the muscle forces was calculated by a static optimization taking into account ground reaction and knee flexion/extension during walking. The effect of patellar instability was obtained by gradually unbalancing this symmetry, one side was unloaded till 90 N, and the other loaded till 110 N. Results: Unbalanced forces of 10 N acting on the retinaculum alone can produce a real difference in displacements of about 7 mm, and an increment of about 44% on patellar contact forces. Conclusion: This research demonstrated how an unbalanced forces acting on the retinaculum can produce significant patellar instability. Patellar instability starts at 25-30° of the knee flexion angle but tends to appear at 15° when the unbalanced muscular loading conditions are acting.

Impact of COVID-19 on hand surgery in Italy: A comparison between the Northern and the Southern regions.

The aims of this study were to evaluate the impact of the COVID-19 pandemic on emergency and elective hand surgery in four Italian regions that had either a high (Lombardy and Piemonte) or a low (Sicilia and Puglia) COVID-19 case load to discuss problems and to elaborate strategies to improve treatment pathways. A panel of hand surgeons from these different regions compared and discussed data from the centers they work in. The COVID-19 pandemic had an enormous impact on both elective and emergency surgery in Italy, not only in highly affected regions but also - and paradoxically even at a higher extent - in regions with a low COVID-19 case load. A durable and flexible redesign of hand surgery activities should be promoted, while changing and hopefully increasing human resources and enhancing administrative support. Telematics must also be implemented, especially for delivering rehabilitation therapy.

FEM Analysis of Mandibular Prosthetic Overdenture Supported by Dental Implants: Evaluation of Different Retention Methods.

Prosthetic rehabilitation of total edentulous jaws patients is today a common technique that clinicians approach in their daily practice. The use of dental implants for replacing missing teeth is going to be a safe technique and the implant-prosthetic materials give the possibility of having long-term clinical success. Aim of this work is to evaluate the mechanical features of three different prosthetic retention systems. By applying engineering systems of investigations like FEM and von Mises analyses, how the dental implant material holds out against the masticatory strength during the chewing cycles has been investigated. Three common dental implant overdenture retention systems have been investigated. The ball attachment system, the locator system, and the common dental abutment have been processed by Ansys Workbench 15.0 and underwent FEM and von Mises investigations. The elastic features of the materials used in the study have been taken from recent literature data. Results revealed different response for both types of device, although locator system showed better results for all conditions of loading. The data of this virtual model show all the features of different prosthetic retention systems under the masticatory load. Clinicians should find the better prosthetic solution related to the patients clinical condition in order to obtain long-term results.

Invasive macrodystrophia lipomatosa of the hand.

OBJECTIVE: The Authors point out the interest of differential diagnosis and conservative surgical treatment of a rare case of digital and ulnar side of the hand gigantism, with massive fatty infiltration of soft tissues and a neurovascular bundle, to be included into Macrodystrophia Lipomatosa with fibrolipomatous hamartomata. PATIENTS AND METHODS: Excision of the mass included 4th ray disarticulation (the fifth had been amputated several years ago) as well as microsurgical external and internal neurolysis of the ulnar nerve, the ulnar neurovascular bundle being exposed and covered with dermal substitute INTEGRATM, with a good result both from a cosmetic and functional point of view at three year follow up. RESULTS: This is the first report of INTEGRATM covering of a neurovascular bundle. Samples taken from the dermal substitute matrix interface at day 6 and day 25 were examined with transmission Electron Microscopy: a newly formed tissue, rich in precursor cells, was detected. CONCLUSIONS: Conservative surgery, requiring particular microsurgical skills and use of dermal templates, plays an outstanding role in treatment of these rare but aggressive soft tissues masses of the upper limb.

FEM and Von Mises analyses of different dental implant shapes for masticatory loading distribution.

The rehabilitation of edentulous patients is today a challenge for the clinicians. The healthy of the hard and soft issue may be considered a fundamental element for having long-term results. The dental implant progresses about the predictable and safe results made this technique chosen from a large group of practitioners. However some problems related intra-operative and postoperative conditions may create discomfort on the patients and consequently to the clinician. The unfavourable results are often related to the bone tissue quality but sometime the dental implant shape and the prosthesis framework may undergo to technical difficulties. The purpose of this work is, through the use of appropriate FEM models, to analyse the effect of all these parameters in the construction of a prosthesis type "Toronto", evaluating all the surgical and prosthetic components in order to direct the choices made by the surgeon and to optimize the distribution of loads reducing the patient's discomfort and having a long term clinical success.

Isolated fracture of the capitate with rotation of the proximal fragment. Case report.

A case of capitate fracture in a 28-year-old man, with a 180-degree rotation (volar dislocation) of the proximal fragment is reported. Due to a late diagnosis, the patient presented 2 weeks after trauma. Open reduction and internal fixation with Kirschner wires provided good bone alignment, uneventful healing and a good range of wrist motion was achieved. The authors remind the reader the possibility of capitate fracture, a rare but troublesome event among wrist traumas, requiring a prompt diagnosis and treatment to relief important wrist pain and to restore function. Moreover, in consideration of important vascular complications, producing non-union and arthritis, the emerging role of imaging in detecting even minor signs of bone necrosis, leading to correct surgical indications, has to be taken into account.

Homodigital dorsal adipofascial reverse flap: anatomical study of distal perforators and key points for safe dissection.

Dorsal adipofascial flaps have been used in the surgical reconstruction of complex injuries distal to the eponychial fold. Such injuries produce nail matrix devascularization/necrosis so that nail bed reconstruction can be a challenging technical problem. Irregular scarring of the nail bed and regrowth anomalies of the nail lamina can result, with both functional and cosmetic impairment of the finger. This study aimed to define the precise vascular anatomy of the dorsal adipofascial flap that has previously been used to reconstruct such complex soft tissue defects. Specifically, the purpose was to identify the key points of safe dissection for these flaps. Anatomical dissections were performed on 32 long fingers. The vascular tree was injected with suitable contrast and the distal dorsal region of the long fingers was studied.

Parametric analysis of the strength in the ''Toronto'' osseous-prosthesis system.

AIM: The aim of this work is to analyze how the different distributions of the chewing load could be related to dental prosthesis fractures of the Toronto restoration via the fulfilment of a virtual parametric model. Moreover investigation about implant positions and perspectives in comparison with a virtual medial plane was made to evaluate the incidence of screw and prosthesis breakage. METHODS: Finite element analysis of the lower jaw was performed to underline parameters and mechanical features of dental implants connected with the fractures of the prosthetic restoration. Jaw virtual model and 3D fixtures (Global Sweden and Martina) were created by Cosmos-Solid Works. Matlab was used to recreate the distribution of an unspecific chewing phase analyzing the overall load on the fixtures of the lower jaw. RESULTS: Four virtual 3D models were performed with Matchad 14, for data analysis. The study investigated frontal and horizontal planes and vertical direction of the occlusal forces. Data results showed how position and perspective of fixtures strongly influenced the stress distribution upon the bone of the jaw; safeguard of prostheses elements like cantilever, passing screws, and dental implants are strictly related to a correct selection of the dental implant position. CONCLUSIONS: The 3D geometry of the jaw is an important condition for the choice of position, number, diameter and length of dental implants used for Toronto prostheses. This study would suggest a virtual ''method'' to help the surgeon choosing a correct model for a prosthetic rehabilitation evaluating position, perspective, and stress distribution of the chewing strengths.

Cemented-retained vs screw-retained implant restorations: an investigation on 1939 dental implants.

AIM: The aim of this work was to present a comparison of screw-retained and cemented-retained implant prostheses based on a retrospective analysis of 1 939 dental implants. The advantages, disadvantages, and limitations of those two different types of dental restorations are discussed and compared with the recent international literature. It is important to underline the influence of the attachment mechanism on many clinical aspects of implant dentistry. METHODS: A group of 527 patients was analyzed. All of the patients required implant rehabilitation. 1 939 dental implants were positioned between January 1997 and December 2003. RESULTS: The analyzed clinical trials show the presence of several factors essential to the long-term success of any implant prosthesis. Aesthetic, retrievability, passivity of framework, occlusion, ease of fabrication and cost and retention. In this study, 762 cemented dental prostheses were used for 1 551 dental implants placed. The survival rate of this rehabilitation was 98.4 % with an average of 34.7 month follow-up; 84 screwed-dental prostheses were placed on 330 dental implants. The success percentage of this type of prostheses was 100% with an average of 44.3 month follow-up. CONCLUSION: Cemented-implant prosthesis and screw-retained implant prosthesis analyzed in this investigation, present with advantages and disadvantages. Clinicians should be aware of the limitations and disadvantages of each type of prosthesis, so as to select the one that is most appropriate for a given clinical situation.

[Surgery and rehabilitation of flexor tendons injuries in zone 1 and 2]. / Chirurgia e riabilitazione delle lesioni dei tendini flessori in zona 1 e 2.

BACKGROUND: Prevention of adhesions that restrain tendon gliding is based on early mobilization techniques. Such approach, anyway, does not guarantee positive outcomes. METHODS: Seventy-five patients for a total number of 98 flexors tendons have been treated at the University Hospital of Messina between December 1993 and January 2000. Twenty-five patients, for a total number of 26 tendons, have been seen at follow-up. Seventeen lesions involved zone 2 and 9 involved zone 1. The modified Kessler suture has been generally used. All the repairs have been followed by an adequate early mobilization protocol, according to Kleinert (passive extension/active flexion) in nine patients and according to Risitano and Savage (active extension/active flexion) in 16. RESULTS: Minimum follow-up was 12 months. We present results with an assessment performed according to Strickland and to Elliot for lesion in zone 1 and according to Strickland and using Total Active Motion of the finger for lesions in zone 2. CONCLUSIONS: The suturing technique and mobilization protocol did not affect results, but we made some considerations about respective advantages and disadvantages of either method.

[Traumatic lesions of the hand extensor system: epidemiology and surgical considerations]. / Le lesioni traumatiche dell'apparato estensore della mano: epidemiologia e considerazioni chirurgiche.

AIMS: To investigate demographics, modalities and type of injuries among a population of isolated traumatic injuries of extensor tendons in order to evaluate the consequences on health service and on prevention. METHODS: Retrospective study of injuries treated at the divisions of Plastic Surgery and Orthopedics in a third level referral center among the years 1993-1999. MAIN RESULTS: Data from 173 patients were analyzed, a prevalence of males (81%) and injuries at home (55%) has been observed. Especially young adults (46.88%) have been involved, the thumb has been most interested finger and the middle finger the least, with two peaks of incidence in spring and autumn. The lesions, exposed through an extension of the existing wound, have been usually sutured according to Kessler, adding an early protected motion protocol. CONCLUSIONS: We discuss the possible causes and consequences of data observed, with special reference to the possibility of treating isolated extensor tendon injuries at district hospitals by non-hand surgeons, and primary actions of prevention.

Clinical results and thoughts on sensory nerve repair by autologous vein graft in emergency hand reconstruction.

Lesions of the digital and other sensory nerves in the hand are common. Based on experimental studies on vein graft as a support for peripheral nerve regeneration, the Authors have been using a simple vein graft to bridge sensory nerve gaps when treating acute hand injuries. This is a retrospective study on the results of 22 sensory nerves repaired using vein grafts in cases in which primary suture was not feasible, in emergency hand reconstruction. Patients were informed that a secondary nerve graft could possibly be necessary in the future. Patients were reviewed by two independent observers at least one year after repair and evaluated using the Highest scale as modified by MacKinnon & Dellon. Evaluation chart included influence of repair on rehabilitation program and presence of painful neuromas and scars as well as patient satisfaction. Results were classified according to Sakellarides and 20/22 were classified as very good or good. Cases classified as poor were satisfied and no secondary nerve grafting has been carried out. Rehabilitation of the associated lesions (tendon lacerations or bone and soft tissue damage) was not influenced by the nerve repair and no painful neuroma was reported in the series. In conclusion, since the literature shows unsatisfactory results in repair of digital nerves with nerve grafts, since it's been demonstrated that an unrepaired sensory nerve leads to painful scar and painful neuroma and since we are reluctant to use nerve grafts in emergency procedures, we recommend this simple method because it is easy, low-cost and effective.

The Ununited Scaphoid:Prognostic Factors in Delayed and Nonunions of the Scaphoid.

This study attempts to classify scaphoid nonunions, identify the prognostic indicators of scaphoid nonunions and report the clinical, functional and radiographic results of scaphoid nonunions treated by Herbert screw and bone grafting. The patient population included 51 scaphoid nonunions in 50 patients treated by Herbert screw with or without bone graft. Group I was patients with delayed union; Group II was stable nonunions, Group IIIA consisted of unstable nonunions without DISI; Group IIIB included unstable nonunions with DISI deformity. Although the overall union rate was 84%, 87% stable nonunions (Groups I and II) united compared to only 60% unstable (Groups IIIA and B). This was statistically significant using the Chi-square test at p < 0.05. Thus, delayed unions and stable nonunions unite readily but unstable and displaced nonunions have significantly lower rates of union even after Herbert screw and bone grafting.

Focal hand dystonia in a patient with thoracic outlet syndrome.

A patient affected by thoracic outlet syndrome, with an involvement of the left lower primary trunk due to a rudimentary cervical rib, developed a severe hand dystonia on the same side. The dystonic posture was characterised by a flexion of the wrist with the fingers curled into the palm. Polygraphic recordings performed on the left flexor digitorum superficialis (FDS4) and extensor digitorum superficialis (EDC4) muscles, during a repetitive tapping task of the fourth digit, showed a loss of well formed bursts without a clear silent period along with long duration bursts of cocontraction in antagonistic muscles. The study of reciprocal inhibition between forearm flexor and extensor muscles showed a reduced amount of inhibition in both the disynaptic and the later presynaptic phase of inhibition. The patient underwent an operation with resection of the cervical rib. Twelve hours after the operation the patient experienced a significant improvement of the hand dystonia; the distonia had disappeared completely by two months with a progressive normalisation of reciprocal inhibition.

The use of totally de-proteinized heterologous bone graft in non-union of the scaphoid.

In an attempt to avoid the complications associated with taking autologous bone graft for use in the treatment of non-union of the scaphoid, a clinical trial of the use of totally de-proteinized heterologous bone graft has been carried out. Ten patients with established non-union of the scaphoid were treated with internal fixation and grafting using one such commercially available material, Pyrost. The clinical and radiological results in eight patients about one year later are reported. The operative use of this material proved difficult because of its poor mechanical properties and it is not recommended as a substitute for the patient's own bone.

Angiolymphoid hyperplasia with eosinophilia in the hand: a case report.

Angiolymphoid hyperplasia is an uncommon condition which may give rise to difficulty in diagnosis. The case described was originally regarded as Kaposi's sarcoma, but H.I.V. testing was negative. Excision of a further lesion established the diagnosis as angiolymphoid hyperplasia.

Mucous cyst of the distal interphalangeal joint: treatment by simple excision or excision and rotation flap.

Thirty-five patients who had thirty-seven mucous cysts excised from the distal interphalangeal joints were reviewed not less than one year later. Seven out of 25 which had been treated by simple excision recurred, whereas only one out of twelve treated by excision and skin closure with a rotation flap recurred.

Flexor tendon repair using a "six strand" method of repair and early active mobilisation.

A "six strand" method of tendon repair has been used to treat 36 fingers with flexor tendon lacerations. Following surgery, active mobilisation in a protective splint was begun immediately. 63% of lacerations were in zone 2 and 27% in zone 1. 69% and 100% respectively achieved an excellent or good result using Buck-Gramcko's assessment method. 81% of all the fingers were rated excellent or good.