Background High-grade surface osteosarcoma (HGSOS) is a rare subtype of osteosarcoma, accounting for approximately 1% of all cases. Due to its rarity, data on clinical characteristics, treatment, and outcomes remain limited. Methods Patients with a histologically confirmed diagnosis of HGSOS registered in the Cooperative Osteosarcoma Study Group (COSS) between 1978 and 2021 were retrospectively analyzed. Event-free survival (EFS) and overall survival rate (OAS) were estimated using Kaplan–Meier analysis, and potential prognostic factors were explored. Results Thirty-one patients met the inclusion criteria. Median age at diagnosis was 16.8 years, and tumors were predominantly located in the extremities (83.9%). Primary metastatic disease at diagnosis was rare (n = 1). At a median follow-up of 5.33 years, 3- and 5-year EFS were 79.5% and 75.3%, while 3- and 5-year OAS were 82.7% and 78.1%, respectively. Larger tumor volume, poor histological response to neoadjuvant chemotherapy, and early recurrence were associated with inferior outcomes in univariate analyses. In multivariate analysis, tumor localization in an extremity was identified as the only independent predictor of overall survival. Conclusions Patients with HGSOS treated within multimodal osteosarcoma protocols demonstrated favorable survival outcomes. Prognostic interpretation is limited by the small cohort size; however, tumor localization, tumor volume, histological response, and timing of recurrence appear to influence outcome. Larger collaborative studies are needed to further define prognostic factors in this rare tumor entity.

PURPOSE:Teleangiectatic osteosarcoma is a histologic subtype of osteosarcoma that can mimic aneurysmal bone cysts and has so far been incompletely characterized. PATIENTS AND METHODS:We used the database of the Cooperative Osteosarcoma Study Group COSS (patient-registration 1980-2019) to better understand this rare histologic variant. RESULTS:223 eligible patients were identified, 164 having reference pathology (median age 15.9 (3.7-69.7) years; male 134, female 89; tumor sites limb 208 (201 metaphyses, 66 pathologic fractures), trunk 13, head & neck 2; 26 with primary metastases). Known tumor-predisposition syndromes were rare. Therapy included surgery in 215, radiotherapy in 10, and chemotherapy in all patients. Tumor response to preoperative treatment was good in 71% of 165 cases with available data. After a median follow-up of 7.1 (0.2-32.1) years for all patients and 10.5 (0.2-32.1) years for 152 survivors, 5-/10-year actuarial event-free and overall survival expectancies were 61%/57% and 73%/66%, respectively. Five unrelated malignancies occurred during this period. The presence of primary metastases, pathologic fracture, poor response to neoadjuvant chemotherapy, and not obtaining a complete macroscopic remission were associated with inferior outcomes for both event-free and overall survival (p < 0.01). DISCUSSION:This large analysis proves teleangiectatic osteosarcoma to be a disease predominantly of the metaphyses of the young. While detected only rarely, the true incidence of genetic tumor predispositions would require prospective assessments. Behaving like other osteosarcoma subtypes in many other ways, this variant may show greater chemosensitivity and hence somewhat better outcomes than other subtypes.

BACKGROUND/AIM:The diaphyses of long tubular bones are a very rare primary site of osteosarcomas and their characteristics and disease course are only poorly defined. PATIENTS AND METHODS:We screened the Cooperative Osteosarcoma Study Group's (COSS) database for eligible cases and detected 162 (130 high-grade central, 3 low-grade central, 6 high-grade surface, 17 periosteal, 6 parosteal). Tumor characteristics, treatments, and outcomes were then investigated. RESULTS:Affected individuals were 86 males and 76 females, with a median age 16.0 (5.0-65.2) years). Tumors of the leg represented 88%, those of the femur alone 74%. Primary distant metastases affected 21% of patients. Treatments consisted of surgery (96%), radiotherapy (4%), and/or chemotherapy (97%). Tumor-response to neoadjuvant chemotherapy was good (<10% viable tumor) in 45% of 115 evaluable cases. After a median follow-up of 5.4 years, 5-year overall-/event-free survival expectancies were 75% and 57%, respectively. First events were mainly metastatic. By histology, five-year survival/event-free survival expectancies were 69%/52% for high-grade central and 100%/79% for periosteal osteosarcomas. The absence of primary metastases, no necessity to perform ablative surgery, a good response to preoperative chemotherapy, and achieving a macroscopic surgical remission were prognostically significant upon multivariate testing. CONCLUSION:Diaphyseal and metaphyseal osteosarcomas share many characteristics. The former may, however, be associated with an increased rate of primary metastases and a lower response-rate to chemotherapy. Overall prognosis and prognostic factors seem comparable. Treatment strategies should follow those established for osteosarcoma.

BACKGROUND:Osteosarcoma may arise as a secondary malignancy following rhabdomyosarcoma (RMS). We utilized the Cooperative Osteosarcoma Study Group (COSS) database to better understand this association. PATIENTS AND METHODS:The COSS database (1980-05/2023) was searched for patients whose osteosarcoma was preceded by RMS. Eligible patients were analyzed for patient-, tumor-, and treatment-related variables as well as outcomes. RESULTS:The search revealed 28 eligible osteosarcomas (27 high-grade central, one periosteal; male:female = 16:12; median age RMS 2.1 [range: 0.9-10.0] years, osteosarcoma 13.5 [7.2-29.0] years). Genetic tumor-predisposition syndromes were documented in 12 patients. One patient had had a distinct malignancy prior to RMS, two intermittently, seven following osteosarcoma. Local RMS treatment had included radiotherapy in 20/26 cases (two unknown). Secondary osteosarcoma sites were extremity 13, trunk seven, head and neck eight; 15 osteosarcomas were radiation-associated. There was only one case of primary osteosarcoma metastases. Osteosarcoma treatment included chemotherapy (27), surgery (26), or radiotherapy (2). A macroscopically complete remission of all osteosarcoma sites was achieved in 24 cases. Median follow-up was 5.8 (range: 0.5-18.4) years after osteosarcoma and 8.1 (1.0-15.4) years for 14 survivors. Actuarial 5-year overall and event-free survival were 66% (standard error 9%) and 45% (10%), respectively. Five of 14 deaths were caused by further malignancies. CONCLUSION:This series offers a benchmark for patients who develop a secondary osteosarcoma after RMS. Affected patients are generally still in the pediatric age. The results obtained strongly argue for genetic predisposition testing in RMS and against therapeutic leniency in comparable situations.

BACKGROUND:Primary therapy of localized myxofibrosarcoma (MFS) remains controversial. Primary resection is complicated by a high rate of local recurrence, and the refractoriness to non-surgical treatment results in a higher risk of metastasis. The aim of the present study was to contribute the findings of a single sarcoma-specialized center and encourage investigating new treatment options. PATIENTS AND METHODS:We analyzed 134 patients treated with localized MFS in our center regarding prognostic factors defining overall survival, local recurrence, and metastasis. We focused on multimodal treatment of localized MFS: surgery, radiation, chemotherapy, hyperthermia, and isolated limb perfusion. RESULTS:The 5-year OS was 74.9%. From a total of 134 patients: 74 (55.2%) stayed disease free, 48 (35.8%) had a local recurrence (LR), and 23 (17.2%) developed a distant metastasis (DM). The 5-year LR-free survival (LRFS) and DM-free survival (DMFS) were 66.1% and 80.8%, respectively. Older age, tumor size (cT) cT ≥ 2, non-extremity localization, and distant metastasis were adverse predictive factors for OS. Performing an incision biopsy, surgery in a sarcoma-center, wide local excision or compartment-oriented excision, negative margins, and radiotherapy were positive predictive factors for LR. Tumor size cT ≥ 3 was a negative predictive factor for DM. Grading was a negative predictive factor for LR (G ≥ 2) and for DM (G3) in the multivariable analysis. CONCLUSION:Adjuvant radiation had a positive impact on LRFS in all localized tumor stages, even in cT1 tumors. Chemotherapy did not have a significant impact on DMFS, regardless of tumor stage. Our findings indicate that myxofibrosarcoma may be a chemotherapy-resistant entity and a much closer monitoring is required, in case of neoadjuvant treatment.

Background: To evaluate patient and tumour characteristics, treatment, and their impact on survival in patients with multi-systemic metastases at initial diagnosis of high-grade osteosarcoma. Precedure: Eighty-three consecutive patients who presented with multi-systemic metastases at initial diagnosis of high-grade osteosarcoma were retrospectively reviewed. In cases of curative intent, the Cooperative Osteosarcoma Study Group recommended surgical removal of all detectable metastases in addition to complete resection of the primary tumour and chemotherapy. Results: Eighty-three eligible patients (1.8%) were identified among a total of 4605 individuals with high-grade osteosarcoma. Nine (10.8%) of these achieved complete surgical remission, of whom seven later had recurrences. The median follow-up time was 12 (range, 1–165) months for all patients. Actuarial event-free survival after 1, 2, and 5 years was 9.6 ± 3.2%, 1.4 ± 1.4%, and 1.4 ± 1.4%, and overall survival was 54.0 ± 5.6%, 23.2 ± 4.9%, and 8.7 ± 3.3%. In univariate analyses, elevated alkaline phosphatase before chemotherapy, pleural effusion, distant bones as metastatic sites, and more than one bone metastasis were negative prognostic factors. Among treatment-related factors, the microscopically complete resection of the primary tumour, a good response to first-line chemotherapy, the macroscopically complete resection of all affected tumour sites, and local treatment (surgery ± radiotherapy) of all bone metastases were associated with better outcomes. Tumour progression under first-line treatment significantly correlated with shorter survival times. Conclusion: The outlook for patients with multi-systemic primary metastases from osteosarcoma remains very poor. The utmost importance of surgical resection of all tumour sites was confirmed. For unresectable bone metastases, radiotherapy might be considered. In the patient group studied, standard chemotherapy was often insufficiently effective. In the case of such advanced disease, alternative treatment options are urgently required.

Aims Giant cell tumour of bone (GCTB) is histologically defined as a lesion containing reactive giant cells and a neoplastic mononuclear cell population; in up to 92% of cases, GCTB is characterised by a specific mutation of the histone gene H3F3A. The cellular composition ranges from giant-cell-rich to giant-cell-poor. The diagnosis of GCTB can be challenging, and several other lesions need to be excluded, e.g. aneurysmal bone cysts, non-ossifying fibromas, chondroblastomas, brown tumours, and giant-cell-rich osteosarcomas. Our aim was to analyse the clinical history, imaging, molecular pathology and histology of three H3F3A-mutated bone tumours without detectable giant cells. None of the patients received denosumab therapy. Methods and results Diagnostic material was obtained by curettage or resection and/or biopsy. Common histomorphological features of all three reported lesions were fibrocytic, oval cells in a background of osteoid and an absence of multinuclear giant cells as confirmed with CD68 immunohistochemistry. We used immunohistochemistry and Sanger sequencing to demonstrate positivity for the H3.3 p.G34W mutation. Differential diagnoses were systematically excluded on the basis of histomorphology, immunohistochemistry, and fluorescence in-situ hybridisation. The imaging (radiography, computed tomography, and magnetic resonance imaging) for all three cases is presented and discussed. Conclusions We believe that these GCTBs without giant cells expand one end of the heterogeneous range of GCTB. Because of the lack of giant cells, correct diagnosis of GCTB is challenging or even impossible on histological grounds alone. In these cases, detection of the characteristic H3F3A mutation (G34W-specific antibody RM263 or sequencing) is extremely helpful for diagnosing those lesions without giant cells as giant cell tumours of bone.

Indolent systemic mastocytosis (ISM) is a group of heterogenous diseases characterized by abnormal accumulation of mast cells in at least one organ. ISM can be a cause of osteoporosis. The aim of this study is to determine the prevalence, and the prognosis of ISM in a cohort of patients with osteoporosis. In this monocentric and retrospective study, patients with osteoporosis who did not receive a bone biopsy (cohort 1) and patients that subsequently received a diagnostic bone biopsy for differential diagnosis (cohort 2) are compared with patients who are diagnosed with ISM (cohort 3). A total of 8392 patients are diagnosed with osteoporosis. Out of these patients 1374 underwent a diagnostic bone biopsy resulting in 43 patients with ISM. These figures indicate that ISM is diagnosed in 0.5% of patients with osteoporosis and in 3.1% (men 5.8%) of patients who underwent bone biopsies. Patients with ISM sustained significantly more vertebral fractures in comparison to patients in cohort 2 (4.4 ± 3.6 versus 2.4 ± 2.5 vertebral fractures, p < 0.001) and women were significantly younger compared to cohort 2 (57.3 ± 12 versus 63.6 ± 12 years, p < 0.05). Only 33% showed an involvement of the skin (urticaria pigmentosa). ISM is a rare cause of osteoporosis (0.5%). However, in a subgroup of rather young male patients with osteoporosis the prevalence is more than 5%. Thus, ISM should be considered in premenopausal women and men presenting with vertebral fractures even if urticaria pigmentosa is not present.

Hallux rigidus is degenerative arthritis of the first metatarsophalangeal joint characterized by pain and stiffness in the joint with limitation of motion and functional impairment. Recently, bone grafts have been introduced in orthopedic procedures, namely osteosynthesis and arthrodesis. Allografts can induce bone formation, provide support for vascular and bone ingrowth and have a low risk of immunological rejection. A 52-year-old female patient with hallux rigidus underwent arthrodesis of the first metatarsophalangeal joint using Shark Screw® made of allogenic cortical bone. Corrective surgery was performed after 10 weeks, and a 5 × 3 mm large part of the Shark Screw® with the surrounding patient’s bone was removed. A histological evaluation revealed a vascularized graft with the newly formed compact lamellar bone fitting exactly to the cortical graft. The bone surface was lined by plump osteoblasts with osteoid production, and osteocytes were present in the lacunae. The arthrodesis of the first metatarsophalangeal joint using an allogenic cortical bone graft results in fast, primary bone healing without immunological rejection. This case suggests that the cortical allograft is a good and safe treatment option with an excellent graft incorporation into the host bone. However, as the literature evaluating the histology of different bone grafts is scarce, further high-level evidence studies with adequate sample sizes are needed to confirm our findings.

This review presents the current understanding of the etiology, pathogenesis, and how to diagnose and treat osteochondritis dissecans (OCD) at the elbow joint followed by an analysis of particular characteristics and outcomes of the treatment. OCD is seen in patients with open growth plates (juvenile OCD [JOCD] and in adults [AOCD] with closed growth plates [adult OCD). The etiology at smaller joints remains as unclear as for the knee. Mechanical factors (throwing activities [capitulum] seem to play an important role. Clinical symptoms are unspecific. Thus, imaging techniques are most important for the diagnosis. In low-grade and stable lesions, treatment involves rest and different degrees of immobilization until healing. When surgery is necessary, the procedure depends on the OCD stage and on the state of the cartilage. With intact cartilage, retrograde procedures are favorable while with damaged cartilage, several techniques are used. Techniques such as drilling and microfracturing produce a reparative cartilage while other techniques reconstruct the defect with osteochondral grafts or cell-based procedures such as chondrocyte implantation. There is a tendency toward better results when reconstructive procedures for both the bone and cartilage are used. In addition, comorbidities at the joint have to be treated. Severe grades of osteoarthritis are rare.

This is a review on talus osteochondritis dissecans and talus osteochondral lesions. A majority of the osteochondral lesions are associated with trauma while the cause of pure osteochondritis dissecans is still much discussed with a possible cause being repetitive microtraumas associated with vascular disturbances causing subchondral bone necrosis and disability. Symptomatic nondisplaced osteochondral lesions can often be treated conservatively in children and adolescents while such treatment is less successful in adults. Surgical treatment is indicated when there is an unstable cartilage fragment. There are a large number of different operative technique options with no number one technique to be recommended. Most techniques have been presented in level II to IV studies with a low number of patients with short follow ups and few randomized comparisons exist. The actual situation in treating osteochondral lesions in the ankle is presented and discussed.

ZusammenfassungRiesenzelltumore des Knochens gehören zu den Tumoren mit intermediärer Dignität, deren biologisches Verhalten aus dem histologischen Bild nicht sicher prognostiziert werden kann. Häufig zeigen sie ein lokal aggressives, destruierendes Ausbreitungsverhalten und neigen bei unvollständiger Entfernung zu Lokalrezidiven. Auch pulmonale Fernmetastasen kommen vereinzelt vor. Die Diagnostik erfordert bei spinaler Manifestation neben Anamnese, klinischen Befunden und Laborbefunden eine Schnittbildgebung mit CT und MRT, die Sicherung der Diagnose sollte mittels Biopsie erfolgen. Die histologische Beurteilung sollte von Pathologen mit Erfahrung in der Knochentumordiagnostik durchgeführt werden. Aufgrund der Rezidivneigung ist chirurgisch die extraläsionale, weite Exzision des Tumors notwendig, in der Regel mit einer suffizienten Fixation und Fusion. Enge postoperative Verlaufskontrollen sind erforderlich. Neue Aspekte in der begleitenden Therapie ermöglicht der humane monoklonale Antikörper Denosumab.In diesem Artikel zu Riesenzelltumoren der Wirbelsäule berichten wir über Erfahrungen in den letzten 20 Jahren in unserer Klinik, beschreiben 2 Fälle beispielhaft und gehen auf die Diagnostik und neue Aspekte der Therapie mit Denosumab ein.

PURPOSE:The objective of this study was to investigate potential correlations between pathologic fractures (PFs) and prognosis of patients with primary central high-grade osteosarcoma of the extremities.METHODS:We retrospectively analyzed 2,847 patients registered in the Consecutive Cooperative Osteosarcoma Study Group database with primary central high-grade osteosarcoma of the extremities, treated between 1980 and 2010. Intended treatment included pre- and postoperative chemotherapy and surgery. Univariable and multivariable survival analyses were performed for all patients and then differentiated for adult and pediatric (≤ 18 years at time of diagnosis) patients.RESULTS:A total of 2,193 patients were ≤ 18 years of age; 11.3% of all patients had PFs. In the overall cohort, presence of PF correlated significantly with tumor site, histologic subtype, relative tumor size, and primary metastases, but not with body mass index or local surgical remission. In univariable analysis, 5-year overall survival (OAS) of patients with and without PF was 63% versus 71%, respectively (P = .007), and 5-year event-free survival (EFS) was 51% versus 58% (P = .026). In pediatric patients, OAS and EFS did not differ significantly between patients with and without PF. In adults, 5-year OAS in patients with and without PF was 46% versus 69% (P < .001), and 5-year EFS was 36% versus 56% (P < .001). In multivariable analysis, PF was not a statistically significant factor for OAS or EFS in the total cohort or in pediatric patients. In adult patients, PF remained an independent prognostic factor for OAS (P = .013; hazard ratio [HR], 1.893). It was not a significant prognostic factor for EFS (P = .263; HR, 1.312).CONCLUSION:In this largest study to date with extremity osteosarcomas, we observed the occurrence of PF to correlate with inferior OAS expectancies in adult but not in pediatric patients.

Denosumab is a potent osteoclast inhibitor targeted to prevent osteoporotic bone loss and thereby reduce fractures in the aging population. Recently, an elevated risk of rebound fractures following denosumab discontinuation was identified, unless patients were transitioned to an alternative antiresorptive medication. How denosumab affects the interaction of mechanosensitive osteocytes and bone quality remains unknown. We hypothesized that denosumab influences osteocyte function contributing to bone reorganization and increased fractures during discontinuation. Bone quality and osteocytes were assessed in archived iliac crest bone biopsies obtained from patients with high fracture occurrence from 2011 to 2016. Biopsies were obtained due to high fracture occurrence prior and during osteoporosis therapy from (i) patients with at least two semiannual subcutaneous injections of 60 mg denosumab, (ii) patients with rebound fractures during discontinuation, and (iii) patients of a treatment-naive group. In total, biopsies from 43 individuals were analyzed (mean age, 65.5 ± 12.1 years). Our results showed that during denosumab treatment, iliac cortical bone had a higher bone tissue hardness compared to treatment-naive bone (p = 0.0077) and a higher percentage of mineralized osteocyte lacunae (p = 0.0095). The density of empty osteocyte lacunae was higher with denosumab compared to treatment-naive (p = 0.014) and remained high in trabecular bone during discontinuation (p = 0.0071). We conclude that during denosumab treatment, increased bone hardness may contribute to improved fracture resistance. In biopsies from patients with high fracture occurrence, denosumab treatment reduced osteocyte viability, an effect that persisted during treatment discontinuation. High-resolution imaging of osteocyte viability indicates a role for osteocytes as a potential future mechanistic target to understand rebound bone loss and increased fractures with denosumab discontinuation.

ZusammenfassungWir beschreiben den Fall eines 44-jährigen Patienten, der sich 2011 mit akuten Rückenschmerzen und radiologisch nachgewiesener frischer LWK-Fraktur vorstellte. Neben der frischen Fraktur fielen ältere Kompressionsfrakturen im Bereich der Brust- und Lendenwirbelsäule auf. Die Knochendichtemessung zeigte eine ausgeprägte Osteoporose. Klinisch fiel der Patient durch kleine Hoden auf. Die Diagnostik bezüglich sekundärer Ursachen der Osteoporose zeigte nicht nur einen hypergonadotropen Hypogonadismus, sondern auch das Vorliegen einer systemischen Mastozytose. Die der Osteoporose zugrundeliegenden Pathologien steuerten die Therapieentscheidung. Neben einer Testosteronsubstitution wurde eine Bisphosphonattherapie eingeleitet. Hierunter konnte eine Stabilisierung erreicht werden. Die Knochendichte verbesserte sich um 8 %, und es traten keine weiteren osteoporotischen Frakturen auf. Der Fall zeigt die Wichtigkeit einer vollständigen Diagnostik bezüglich sekundärer Ursachen einer Osteoporose, insbesondere wenn ein ungewöhnlicher Kontext wie bei jungen Männern oder prämenopausalen Frauen vorliegt.

We present the case of a 44-year old male presenting with acute severe back pain and radiologically proven fresh lumbar spine fracture. In addition to the fresh fracture, older compression fractures of the thoracic and lumbar spine were noticeable. Bone densitometry showed severe osteoporosis with a t-score of -3.6. On physical examination, small testicles were noticed. Further workup for secondary causes of osteoporosis showed not only hypergonadotropic hypogonadism but also mastocytosis as a second underlying cause of osteoporosis. Treatment strategies were guided by these findings and included testosterone replacement as well as bisphosphonate therapy. Follow up examinations showed no further progress of osteoporosis. This case report highlights the necessity of complete diagnostic workup in patients with severe osteoporosis, especially in young men or premenopausal women.

Osteosarcoma of the foot is a very rare presentation of a rare tumor entity. In a retrospective analysis, we investigated tumor- and treatment-related variables and outcome of patients registered in the Cooperative Osteosarcoma Study Group (COSS) database between January 1980 and April 2016 who suffered from primary high-grade osteosarcoma of the foot. Among the 23 eligible patients, median age was 32 years (range: 6–58 years), 10 were female, and 13 were male. The tarsus was the most commonly affected site (n=16). Three patients had primary metastases. All patients were operated: 5 underwent primary surgery and 18 received surgery following preoperative chemotherapy. In 21 of the 23 patients, complete surgical remission was achieved. In 4 of 17 patients, a poor response to neoadjuvant chemotherapy was observed in the resected primary tumors. Median follow-up was 4.2 years (range: 0.4–18.5). At the last follow-up, 15 of the 23 patients were alive and 8 had died. Five-year overall and event-free survival estimates were 64% (standard error (SE) 12%) and 54% (SE 13%), which is similar to that observed for osteosarcoma in general. Event-free and overall survival correlated with primary metastatic status and completeness of surgery. Our findings show that high-grade osteosarcoma in the foot has a similar outcome as osteosarcoma of other sites.

This article is a review of the current understanding of the etiology, pathogenesis, and how to diagnose and treat knee osteochondritis dissecans (OCD) followed by an analysis of and outcomes of the treatments available. OCD is seen in children and adolescents with open growth plates (juvenile OCD) and adults with closed growth plates (adult OCD). The etiology of OCD lesions remains unclear and is characterized by an aseptic necrosis in the subchondral bone area. Mechanical factors seem to play an important role. Clinical symptoms are unspecific. Thus, imaging techniques are most important. Regarding treatment, a tremendous number of publications exist. Spontaneous healing is expected unless there is an unstable fragment, and treatment involves rest and different degrees of immobilization until healing. Patients with open physes and low-grade lesions have good results with conservative therapy. When surgery is necessary, the procedure depends on the stage and on the state of the cartilage. With intact cartilage, retrograde procedures are favorable. When the cartilage is damaged, several techniques can be used. While techniques such as drilling and microfracturing produce reparative cartilage, other techniques reconstruct the defect with additional osteochondral grafts or cell-based procedures such as chondrocyte transplantation. There is a tendency toward better results when using procedures that reconstruct the bone and the cartilage and there is also a trend toward better long-term results when comorbidities are treated. Severe grades of osteoarthrosis are rare.

Unter einer Osteomalazie versteht man eine Knochenerkrankung, die mit einer Störung der Skelettmineralisation einhergeht. Es wird eine Vitamin-D-abhängige von einer hypophosphatämischen Form unterschieden. Typisch sind dumpfe, generalisierte Knochenschmerzen, Muskelschwäche und Insuffizienzfrakturen. Das Frakturmuster bei der Osteomalazie unterscheidet sich typischerweise von dem der Osteoporose. Insuffizienzfrakturen im Becken, am Os sacrum, an den Vorfüßen, am Tibiaplateau und an den Rippen sollten in erster Linie an eine Osteomalazie denken lassen, während Schenkelhalsfrakturen und typische Wirbelkörperfrakturen (Keilwirbel, Fischwirbel, Plattwirbel, Deckplattenimpressionsfrakturen) auf eine Osteoporose hindeuten. Der Zeitpunkt der Diagnosestellung kann aufgrund der unspezifischen Beschwerden verzögert sein. Die korrekte Einordnung der Beschwerden ist von der Kenntnis der Pathophysiologie der Osteomalazie und der Durchführung osteologischer Zusatzuntersuchungen abhängig. Die Bestimmung spezifischer Laborparameter sollte nach einem rationalen Algorithmus erfolgen und durch eine Bildgebung sowie ggf. eine Knochenbiopsie ergänzt werden.