[Injuries of the ankle ligaments]

Lateral ligament injuries are the most common injuries of the ankle joint and are usually treated with early weight bearing after a short period of immobilization. If the clinical presentation is suspicious, additional injuries to the deltoid ligament complex and the syndesmosis should be considered. The indications for additional diagnostics should be generously applied. Injuries to the deltoid ligament usually occur as part of a complex ankle injury and should also be addressed in the surgical treatment of accompanying injuries. Chronic instability in this area necessitates complex bony and soft tissue procedures. Syndesmotic injuries with insufficiency of the capsule-ligament apparatus are frequent in ankle fractures and are stabilized during fracture treatment. Isolated syndesmotic instability should also be surgically treated as chronic injuries are usually associated with poor clinical results and early osteoarthritis.

Feasibility and safety of minimally invasive calcaneal osteotomy (MICO) through a medial approach: a case-control study

INTRODUCTION

Minimally invasive calcaneal osteotomy (MICO) is already an established surgical procedure for correcting hindfoot deformities using a lateral approach. So far, no description of a medial approach for MICO has been published.

MATERIAL AND METHODS

Between August 2022 and March 2023, 32 consecutive patients (MICO with medial approach, MMICO: n = 15; MICO with lateral approach, LMICO: n = 17) underwent MICO as part of complex reconstructive surgery of the foot and ankle with concomitant procedures. The amount of correction in the axial view of the calcaneus and consolidation rates were evaluated radiographically. Subjective satisfaction, stiffness of the subtalar joint, and pain level (numeric rating scale, NRS) at the level of the heel were assessed clinically. The last follow-up was at 6 months.

RESULTS

All osteotomies consolidated within 6 months after surgery. Displacement of the tuber was 9 mm on average in either group. Relevant subtalar joint stiffness was detected in 5 MMICO and 6 LMICO patients. No relevant differences between the groups were detected for wound healing problems, nerve damage, heel pain or patient satisfaction.

CONCLUSION

In this study lateral and medial approaches for MICO were performed. Similar degrees of correction and low complication rates were found in both groups. The medial approach for MICO is safe and can be beneficial regarding patient positioning and arrangement of the C‑arm.

[Minimally invasive forefoot surgery: concept and techniques]

Minimally invasive surgery (MIS) has advanced to an established approach in the correction of all deformities of the forefoot. For the first ray the minimally invasive chevron and Akin osteotomy (MICA) shows very good clinical results and provides a broad spectrum of indications in comparison to the classical chevron osteotomy. The minimally invasive treatment of hallux rigidus also seems to achieve comparable results to the open techniques, although the surgical indications must be thoroughly evaluated. Lesser toe deformities are often easier to treat with minimally invasive osteotomy, capsule release and tendon lengthening than with complex open procedures and usually do not require any internal fixation material. Compared to the classical Weil osteotomy, distal metatarsal osteotomy shows a reduced rate of cock-up deformities and does not require internal fixation. In relation to open procedures, minimally invasive approaches should be accepted as a valuable addition and alternative to the classical open techniques due to the reduced rate of wound healing disorders and postoperative pain.

[Injuries of the foot and ankle in winter sports]

Winter sports injuries of the foot and ankle are a relevant entity due to the high enthusiasm for alpine skiing and snowboarding. The condition of the footwear and rigidity of the binding have a significant influence on the pathobiomechanics of fracture development and have been shown to influence the frequency of knee and ankle injuries. Foot injuries are rare due to the sport-specific footwear with good padding and frequent hard shell casings.

[A several-week history of inflammatory changes in the right foot and right hand of a 57-year-old male patient]

Metastatic fat necrosis due to inflammatory or neoplastic pancreatic diseases is rare. This phenomenon is attributed to systemic effects of pancreatic enzymes. Depending on the sites of fat necrosis, a number of different diseases may be mimicked, leading to incorrect diagnosis and therapies. Many case reports describe the phenomenon of skin, joint and bone manifestations of fat necrosis under the acronym PPP (pancreatic, panniculits, polyarthritis) syndrome. The management of "autodigestion" primarily consists of treating the underlying pancreatic disease.

[Lateral instability of the upper ankle joint]

Because of their frequency, ankle sprains are of major clinical and economic importance. The simple sprain with uneventful healing has to be distinguished from the potentially complicated sprain which is at risk of transition to chronic ankle instability. Conservative treatment is indicated for the acute, simple ankle sprain without accompanying injuries and also in cases of chronic instability. If conservative treatment fails, good results can be achieved by anatomic ligament reconstruction of the lateral ankle ligaments. Arthroscopic techniques offer the advantage of joint inspection and addressing intra-articular pathologies in combination with ligament repair. Accompanying pathologies must be adequately addressed during ligament repair to avoid persistent ankle discomfort. If syndesmotic insufficiency and tibiofibular instability are suspected, the objective should be early diagnosis with MRI and surgical repair.

[Gluteal insufficiency: Pathogenesis, Diagnosis and Therapy]

INTRODUCTION

Gluteal insufficiency is a common and challenging complaint. New concepts in pathobiomechanics and improved clinical understanding of chronic gluteal dysfunction have unmasked gluteus medius (GMed) tears as an underlying cause of enhanced trochanteric pain syndrome (GTPS). These tears are often missed or misdiagnosed as bursitis, but lead to prolonged chronic peritrochanteric pain. Clinic: The clinical signs are often dull pain on the lateral hip aspect, reduced hip abduction strength with positive Trendelenburg testing and a tendency for the leg to external rotation, as the internal rotation strength is reduced.

IMAGING

Radiography and ultrasound may be used to confirm the diagnosis, whereas MRI is the modality of choice for imaging. Compensatory hypertrophy of the tensor fascia latae muscle (TFL) and fatty involution (especially of the GMed) are also seen.

THERAPY

Conservative treatment regimens for partial thickness tears involve hip joint centering and strengthening of abductor muscles, sparing TFL. Failed conservative treatment and full thickness tears are treated surgically. Partial tears can be addressed endoscopically with suture anchors for tendon footprint reconstruction. Larger tears involving the anterior and/or lateral facets of the tendon or failed conservative treatment are repaired with minimally invasive open reduction techniques. Double row suture anchor techniques provide anatomical tendon footprint reconstruction. Postoperative rehabilitation is prolonged, due to high acting forces in the peritrochanteric region, and needs to be carried out under professional surveillance.

CONCLUSION

Reconstruction of gluteal tendon tears is often the only solution in the treatment of chronic hip pain due to gluteal insufficiency. Available data suggest that reduction in pain and restoration of abduction power can be achieved in mid-term follow-up.

[Tumors of the foot: diagnostics and therapy]

Despite the compact anatomy with thin soft tissue coverage, diagnosis of both benign and malignant tumors of the foot is often delayed. Diagnostic errors are more common than in other body regions, as neoplasias are rarely considered. Barring a few exceptions the foot is not a typical predilection site for malignant musculoskeletal tumors, although, basically any tumor entity of the musculoskeletal system can affect the foot. Delays in specific diagnostic and therapeutic procedures of these lesions can entail serious consequences for patients as tumor size is a major prognostic factor for recurrence-free survival. In cases of an indistinct persistent swelling or bone lesion a tumorous process should always be considered to ensure early diagnosis and therapy of foot tumors.

[Primary malignant bone tumors]

Among human neoplasms, primary malignant bone tumors are fairly rare. They present an incidence rate of roughly 10 cases per 1 million inhabitants per year. During childhood (<15 years), the percentage of malignant bone tumors amounts to 6% of all infantile malignancies. Only leukemia and lymphoma show a higher incidence in adolescence. Of all primary malignant bone tumors, 60% affect patients younger than 45 years and the peak incidence of all bone tumors occurs between 15 and 19 years. The most common primary malignant bone tumors are osteosarcoma (35%), chondrosarcoma (25%), and Ewing's sarcoma (16%). Less frequently (≤ 5%) occurring tumors are chordoma, malignant fibrous histiocytoma of bone, and fibrosarcoma of bone. Vascular primary malignant tumors of bone and adamantinoma are very rare. Staging of the lesion is essential for systemic therapeutic decision-making and includes complete imaging and histo-pathological confirmation of the suspected entity. In most cases, this is established by open- or image-guided biopsy. Based on this information, an interdisciplinary tumor board will determine the individual therapeutic approach. Endoprosthetic or biological reconstruction following wide tumor resection is the most common surgical therapy for primary malignant bone tumors. There is vital importance in a thorough postoperative follow-up and continous after-care by a competent tumor center which is permanentely in charge of therapy.

[Heterotopic ossifications in total hip arthroplasty: prophylaxis and therapy]

Heterotopic ossification (HO) is a frequent and occasionally severe complication after total hip arthroplasty. Clinical symptoms of this benign abnormal bone formation are loss of mobility and local pain. The etiology and pathomechanisms are not yet completely understood. Overexpression of bone morphogenetic proteins and dysregulation of prostaglandin metabolism seem to be relevant. Medication with non-steroidal anti-inflammatory drugs (NSAIDs) and perioperative single dose radiotherapy are used for prophylaxis, whereby radiotherapy should only be performed in patients with a history of HO or additionally after resection of HO. From currently available data selective cyclooxygenase-2 inhibitors seem to have a preventive efficacy equal to the classical NSAIDs diclofenac and indometacin. This work discusses current knowledge about the pathophysiology, risk factors and the clinical approach for prevention and treatment of HO.

[Haemophilic pseudotumour of the distal femur - a case report and characterisation of this entity]

Haemophilic pseudotumour is a rare disease occurring in 1 % of patients with severe haemophilia as a long-term complication. Because both haemophilia A (factor VIII deficiency) and haemophilia B (factor IX deficiency) are X-linked recessive genetic disorders, pseudotumours are found almost exclusively in men between 20 and 70 years of age. Haemophilic pseudotumour has been defined as a progressive cystic swelling, produced by recurrent haemorrhage, which exerts increasing pressure on nearby structures. As a result, necrosis of skin, muscle and bone can be found. Neurovascular obstruction as well as pathologic fractures are severe complications of this disease. Most patients with pseudotumours are asymptomatic for a long time and many patients report sustaining an injury prior to the development of the tumour. Most haemophilic pseudotumours of the bone are located in the pelvis, femur and hand. We present the case of a 59-year-old male patient suffering from a haemophilic pseudotumour of the right distal femur. After verification of the diagnosis by means of an open biopsy, final surgery with curettage and plombage with bone cement was performed.

A convenient synthesis of N-acetyllactosamine derivatives from lactal

In a thermal inverse-type hetero-Diels-Alder reaction of O-silyl-protected lactal 1 and bis(2,2,2-trichloroethyl) azodicarboxylate (2), the dihydrooxadiazine derivative 3 was obtained in a very high yield; transesterification with benzyl alcohol furnished the corresponding derivative 4. Treatment of 3 with methanol in the presence of BF3.OEt2 afforded the methyl lactoside derivative 5 which, after transesterification with benzyl alcohol, then hydrogenolytic debenzylation and concomitant NN-cleavage with Raney nickel, and N-acetylation, furnished methyl O-(2,4,6-tri-O-tert-butyldimethylsilyl-beta-D-galactopyranosyl)-(1-->4)- 2-acetamido-3,6-di-O-tert-butyldimethylsilyl-2-deoxy-beta-D-glucopyra nos ide (7) in high yield. Desilylation of 4, then O-acetylation, methyl glycoside formation with methanol-BF3.OEt2, hydrogenolytic debenzylation, and NN-cleavage with Raney nickel, and N-acylation afforded methyl O-(2,3,4,6-tetra-O-acetyl-beta-D-galactopyranosyl)-(1-->4)-2-acetamido-3 ,6-di-O-acetyl-2-deoxy-beta-D-glucopyranoside (10).

Synthesis of phosphites and phosphates of neuraminic acid and their glycosyl donor properties--convenient synthesis of GM3

The importance and requirements for catalytic activation of sialyl donors are discussed, leading to the acid sensitive phosphite and phosphate moiety, respectively, as leaving group and nitriles as solvent. Therefore, from readily available N-acetylneuraminic acid, derivative 1 with phosphochloridites 2a-f and Huenigs' base sialyl phosphites 3a-f were prepared and isolated in high yields. Oxidation of 3a,c with tert-butyl-hydroperoxide afforded the corresponding phosphates 4a,c. As expected, phosphites 3 could be activated in acetonitrile by catalytic amounts of TMSOTf; thus, from 3a-e as donors and lactose derivatives 8A,B as acceptors the ganglioside building blocks 9A and 9B, respectively, were obtained in good yields. The best results were obtained with diethyl phosphite derivative 3a as sialyl donor, which exceeded by far the results obtained with the corresponding phosphate derivative 4a. Trisaccharide 9B was transformed into known 9A and into the fully O-acetylated GM3-trisaccharide 10.

Muramic acid derivatives as glycosyl donors for the synthesis of muramyl-containing glycosphingolipids and fatty acids

2-Azido-2-deoxy-4,6-O-isopropylidene-3-O-[(1R)-(methoxycarbonyl)ethyl]- alpha-D-glucopyranosyl trichloroacetimidate (3 alpha) has been used as the glycosyl donor in the synthesis of glycosphingolipids 14 and 27. Reaction of 3 alpha with (2S, 3R, 4E)-2-azido-3-benzoyloxy-4-octadecen-1-ol (6) gave (2S, 3R, 4E)-2-azido-1-(2-azido-2-deoxy-4,6-O-isopropylidene-3-O-[(1R)-1-(m ethoxycarbonyl)ethyl]-beta-D-glucopyranosyloxyl)-3-benzoyloxy-4- octadecene (7), which was converted into (2S, 3R, 4E)-1-(2-deoxy-2-hexadecanoylamino-3-O-[(2R)-propanoyl-(L-alanyl-D -isoglutamine benzyl ester)-2-yl]-beta-D-glucopyranosyloxy)-2-hexadecanoylamino-4-oc tadecen-ol (14). Reaction of 3 alpha with tert-butyldimethylsilyl 2-azido-3,6-di-O-benzyl-2-deoxy-beta-D-glucopyranoside (15) gave tert-butyldimethylsilyl 2-azido-4-O-(2-azido-2-deoxy-4,6-O-isopropylidene-3-O-[(1R)-1-(methox ycarbonyl)ethyl]-beta-D-glucopyranosyl)-3,6-di-O-benzyl-2-deoxy-be ta- D-gluc opyranoside (16 beta), which was converted into 1,3,6-tri-O-acetyl-2-deoxy-4-O-(4,6-di-O-acetyl-2-deoxy-2-hexadecanoy lam ino-3-O-[2R)-propanoyl-(L-alanyl-D-isoglutamine methyl ester)-2-yl]-beta-D-glucopyranosyl)-2-hexadecanoylamino-D-glucopyranose (27).