Anthropometric study of adult tibia bone for pre-operative determination of length of intramedullary nail

Background: The tibia is the bone that is mostly fractured in the body. Surgical fixation of tibia fractures with intramedullary (IM) nail is a common procedure around the world. Objective: This study discusses pre-operative determination of intramedullary nail length to be inserted for a fractured tibia based on  anthropometric measurements of dry tibia bones. Design: This was a prospective descriptive study. Methods: The study involved measurement of length and other parts of adult dry tibia bones. Data of patients that had tibia fracture fixation with intramedullary interlocking nails using SIgn ®nails were also retrieved. All measurements and data obtained were recorded and analyzed using STATA version 13 (StataCorp, Texas. USA). Results: The Maximum Tibia Length (MTL) of 44 adult tibia bones ranged from 35.2cm to 43.6cm with an average of 39.9 ± 2.2cm. The Bicondylar Tibial Width (BTW) ranged from 68.9mm to 80.4mm with an average of 75.1 ± 3.4mm. Tibia length (cm) can be estimated using the equation “12.6 + 3.7*{Bicondylar Tibial width (cm)} ± 3cm”. The distance of the Tibial plateau to the tubercle (TTD) ranged from 2.66cm to 3.53cm with an averageof 3.03 ± 0. 23cm. The Medial Malleolus Height (MMH) ranged from 1.20cm to 1.86cm with an average of 1.51 ± 0. 17cm. Part of the tibia bone that is usually occupied by inserted nail is MTL – (TTD + MMH). Average TTD + MMH = 4.5 ± 0.4cm. Length of intramedullary nail = MTL – 4.5cm. The average length of intramedullary nail used in our centre was 34.7 ± 2.7cm. The difference between the average tibia length and IM nail inserted was 5cm, which is closed to the findings in this study (i.e length of intramedullary nail for a tibia = maximum length of the tibia – 4.5cm). Conclusion: Pre-operative determination of intramedullary nail length for the tibia can be derived using: “Length of the tibia (from the knee joint to the tip of medial malleolus) minus 4.5cm” (for tibia tubercle as the entry point); “Length of the tibia (from the knee joint to the tip of medial malleolus) minus 1.5cm” (for entry point just below the tibia plateau; The diameter of the nail to be inserted can be estimated along with thelength of the IM nail using: Diameter of nail (mm) = {7.2 + 0.007* length of the nail (mm)} ± 1.5 mm. This study also showed that tibia length can be estimated from the equation “12.6 + {3.7*Bicondylar tibial width (cm)} ± 3cm”. This is useful in forensic medicine or when the contralateral limb is not available for use in a patient who is to undergo IM tibia nailing. Key words: Tibia fracture, Pre-operative determination, Intramedullary nail, Tibia bone fixation, Africans, Anthropometry, Tibia, Interlocking nai

Regression equation for estimation of length of humerus from its mophometry in a Nigerian population

Background: While intact long bones are most ideal in estimation of the stature of unidentified individual, in forensic cases as may occur when natural or man-made disasters present bone fragments, regression equations derived from measurements of these bone fragments have been used to determine the length of the intact long bone.Objective: The study reports on the morphometry of the humerus and the estimation of its length using regression equations in a Nigerian population.Methods: The maximum length of the humerus was measured using an osteometric board while the Anatomical neck circumference (ANC), Anatomical neck diameter (AND), mid shaft diameter (MSD), olecranon vertical diameter (OVD), olecranon transverse diameter (OTD), transverse diameter of the inferior articular surface (IASD), transverse trochlea diameter (TTD) proximal point of the caput humeri and collum anatomicum (CHCAD), proximal edge of the fossa olecrani (PEFO) and the most distal point of trochlea humeri (FOTHD) and the biepicondylar width (BEW) of the distal segment were measured using a digital vernier caliper. Partial correlation and Persian regression were used to derive linear regression equations for the measured parameters that showed correlation with the humeral length.Results: Estimation of the maximum length of the humerus from the measures of its ANC, FOTHD, and MSD was achieved with relative accuracy. In deriving regression equations for the length of the humerus of the right and left sides, irrespective of side, the ANC and MSD were both significant in estimating the maximum length of the humerus; on the right side only the ANC exhibited significant correlation, while on the left side both the ANC and FOTHD exhibited significant correlation.Conclusion: These previously unreported findings may help in anthropometric, forensic, and archaeological investigations for the estimation of the stature of the remains of unknown bodies by using regression equations in a Nigerian population.Keywords: Regression equations, humerus, morphometry, Nigerian populatio

The proximal tibia anthropometry in adult Nigerians: Correlation to tibial components of total knee replacement and equations for estimation of its dimensions

Background: The knee joint is commonly affected by osteoarthritis. Total Knee Replacement (TKR) is usually considered for knee osteoarthritis after failure of conservative management. The total knee prostheses used during this procedure are fashioned from bony dimensions of Westerners.Objective: This study compared some of the available tibial baseplate with the proximal tibiae dimension of Nigerians. It also provided equations that can be used to estimate dimensions of different parts of proximal tibia.Design: This was a prospective descriptive study.Methods: Fifty four matured tibiae, comprising 23 right and 31 left bones were measured. Ten parameters were measured and documented. Dimensions of proximal tibia bones from other regions of the world were retrieved from published articles. The dimensions of tibial baseplates were extracted from product monographs. Analyses were done with Microsoft excel 2010 (Microsoft Corporation, Redmond, Washington, United States) and STATA version 13 (Stata Corp, Texas. USA). Statistical significance was set at p ≤ 0.05.Results: There were no significant differences between the left and right tibiae. The average proximal tibia dimension differs from between racial groups. The average aspect ratio calculated was 1.51 ± 0.11. Three of the four implants have sizes that were far larger than the tibiae dimensions, with increment in sizes that were far steep compared to the dimensions of the proximal tibiae. There wasa mismatch of aspect ratio of the tibiae and those of the tibial baseplates. Equation to estimate the anteroposterior dimension for each tibia condyle was generated and tested on published values.Conclusion: This study provided equations that can be used to estimate the anteroposterior dimensions of tibial plateau, the medial and the lateral condyles with the estimated values within ±5mm of the actual value. This can be used as part of pre-operative planning. It also provided data that can be considered in the designing of a suitable tibial baseplate component of total knee prosthesis for Nigerians. Key words: Total knee replacement, Pre-operative, Planning, Proximal tibia, Tibia bone fixation, Nigerians, Africans, Anthropometry, Knee prosthesi

Proximal femoral bone morphological measurements: Relevance in orthopaedic and forensic medicine

Background: Numerous surgical procedures are performed on and around the proximal femur to restore the anatomy and maintain the function of the limb. Hip joint prostheses and surgical implants that are usually used for these procedures were manufactured using dimensions from other populations.Objective: This study documented the anatomic dimensions of proximal femur of Nigerians, devised various equations through regression analysis for pre-operative estimation of certain parts of the proximal femur and for use in forensic medicine. This study also correlated the dimensions of the proximal femur with different surgical implants available.Methods: A total of 56 adult dry femoral bones were studied. Parameters measured were Maximum Femoral Length (MFL), length of the femur between the tip of the greater trochanter and the lateral condyle (termed Trochanteric Length (TL) of the femur), Femoral Neck Length (FNL), Femoral Neck Diameter (FND), Femoral Neck Axial Length (FNAL), Femoral Neck Shaft Angle (FNSA) and Proximal Femoral Shaft Diameter (PFSD). The monographs of surgical implants were obtained. Analyses were done with Microsoft excel 2010 (Microsoft Corporation, Redmond, Washington, United States) and STATA version 13 (StataCorp, Texas. USA). Statistical significance was set at p ≤ 0.05.Results: The average measured values of the parameters were: MFL was 47.9cm, TL was 45.8cm, FNL was 22.9mm, FNAL was 96.9mm, FND was 30.3mm, PFSD was 28.4mm and FNSA was 130.8°. Regression analysis revealed significant statistical relationship between the lengths of femur and other parameters measured; with equations that can be used in clinical settings to estimate certain parameters: MFL = 2.5 + TL; range ± 1cm. FND = 6 + 0.05*TL(mm); range ± 5mm; FNAL = 5 + 0.206*TL(mm); range ± 15mm. TL was used in the equations because it can be measured easily in clinical settings. In forensic medicine, MFL can be estimated from the FND and FNAL, using the equations: MFL = 30.5 + 0.18*FNAL and MFL = 42.14 + 0.19*FND.Conclusion: This study has provided data of the dimensions of proximal femur in Nigerians. Various equations generated from this study will be useful in pre-operative planning, clinical settings and forensic medicines