Osteology, Volume 1, Issue 2 (June 2021) – 4 articles

Background: Periprosthetic joint infection (PJI) is a common yet severe complication after total knee arthroplasty (TKA). Surgical intervention and antibiotic therapy are obligatory to achieve successful, infection-free outcome. Compared to the outcomes after primary TKA, prosthesis failure rates are drastically increased after PJI-dependent revision surgery. Recurrent PJI and aseptic loosening are the most common reasons for prosthesis failure after revision TKA. An open question is the influence of the patients’ gender on long-term prosthesis survival after revision surgery. Additionally, it is unknown whether gender-related parameters and risk factors or differences in treatment are responsible for potential differences in outcome after revision arthroplasty. Patients and Methods: In this report, 109 patients that received TKA revision surgery due to PJI were retrospectively analyzed. We used clinical, paraclinical and radiological examinations to study the influence of gender on the long-term complications aseptic loosening and recurrent PJI after PJI-dependent revision arthroplasty. Results: While overall prosthesis failure rates and risk of recurrent PJI did not differ between genders, the long-term risk of aseptic loosening was significantly elevated in female patients. Postoperative coronal alignment was significantly more varus for women later diagnosed with aseptic loosening. Besides coronal alignment, no gender-dependent differences in clinical presentation or treatment were observed. Conclusions: Female patients displayed a significantly increased risk for aseptic loosening after PJI-dependent revision TKA. The observed gender-dependent differences in long-term outcome in our study support theories surrounding the role of bone metabolism in the development of aseptic loosening. Our data suggest that further research on a female design for PJI-dependent revision prostheses is warranted. Full article

Knowledge of the normal length and skeletal proportions of the lower limb is required as part of the evaluation of limb length discrepancy. When measuring limb length, modern standing full-length digital radiographs confer a level of clinical accuracy interchangeable with that of CT imaging. This study reports a set of normative values for lower limb length using the standing full-length radiographs of 753 patients (61% male). Lower limb length, femoral length, tibial length, and the femorotibial ratio were measured in 1077 limbs. The reliability of the measurement method was tested using the intra-class correlation (ICC) of agreement between three observers. The mean length of 1077 lower limbs was 89.0 cm (range 70.2 to 103.9 cm). Mean femoral length was 50.0 cm (39.3 to 58.4 cm) and tibial length was 39.0 cm (30.8 to 46.5 cm). The median side-to-side difference was 0.4 cm (0.2 to 0.7, max 1.8 cm) between 324 paired limbs. The mean ratio of femoral length to tibial length for the study population was 1.28:1 (range 1.16 to 1.39). A moderately strong inverse linear relationship (r = −0.35, p < 0.001, Pearson’s) was identified between tibial length and the corresponding femorotibial ratio. The PACS-based length measurement method used in this study displayed excellent inter-observer reliability (ICC of 0.99). This study presents a normal range of values for lower limb length in adults and is the first to identify a linear relationship between tibial length and the femorotibial ratio. Full article

We reviewed the characteristics of children hospitalized for bone and joint infections in Luanda, Angola. In a retrospective chart review of 45 patients with childhood osteomyelitis or septic arthritis, 51% of the patients had sickle cell disease, and these patients presented with lower hemoglobin and needed blood transfusion more frequently (p < 0.05). Out of all patients, 64% underwent surgical procedures; a pathological fracture occurred in 31% of the patients. Full article

Surprisingly little is known about the factors released from bone during resorption and the metabolic roles they play. This paper describes what we have learned about factors released from bone, mainly through the study of burn injuries, and what roles they play in post-burn metabolism. From these studies, we know that calcium, phosphorus, and magnesium, along with transforming growth factor (TGF)-β, are released from bone following resorption. Additionally, studies in mice from Karsenty’s laboratory have indicated that undercarboxylated osteocalcin is also released from bone during resorption. Questions arising from these observations are discussed as well as a variety of potential conditions in which release of these factors could play a significant role in the pathophysiology of the conditions. Therapeutic implications of understanding the metabolic roles of these and as yet other unidentified factors are also raised. While much remains unknown, that which has been observed provides a glimpse of the potential importance of this area of study. Full article