Recovering From Hip Fracture according to the Principle of the Three-element Mechanical Theory


A hip fracture is a serious injury, with complications that can be life-threatening. The risk of hip fracture rises with age. Risk increases because bones tend to weaken with age (osteoporosis). Multiple medications, poor vision and balance problems also make older people more likely to fall — one of the most common causes of hip fracture.

Hip fractures are among the most common types of broken bones, and once over the age of 65, a broken hip is the most common reason why people need fracture surgery. Unfortunately, this difficult problem often affects the most vulnerable and frail patients. While some common orthopedic injuries occur in more vigorous, active individuals, the majority of broken hips occur in more sedentary, frail people.

When hip fracture occurs, the conservative treatment of bed rest often brings problems such as pulmonary infection, bedsores, and venous thrombosis of the lower limbs. In addition, most seniors often have chronic diseases such as diabetes, coronary heart disease, and cardiopulmonary insufficiency, etc., and long time bed-ridden inaction gradually leads to body function failure, which makes the mortality rate as high as 50% a year. Therefore, surgery has become the preferred treatment for hip fractures. However, older adults are complicated with severe osteoporosis, which make surgery of fracture fixation difficult, and treatment problems still outstanding: the mortality rate within 1 month after surgery is close to 10%, and within 1 year is 36%. About 11% of the surviving patients are bedridden, 16% of patients require long-term care, and 80% of patients need a walker after 1 year.

Elderly hip fractures have become a major challenge for the global aging society.

In order to solve the problems related to the treatment of hip fractures, Dr. Peifu Tang from the Chinese PLA General Hospital, Beijing, who worked on this study. He spent more than ten years, through the dynamic follow-up of elderly hip fracture patients and imaging studies of failed cases, and found the important reasons for the failure of the operation: loss of medial support, failure of lateral block and overload tension of upper side. Tang further used computational mechanics analysis to put forward the Three-element Mechanical Theory. The basis of this theory is to equate the structural factors maintaining hip stability to a triangular mechanical stability mechanism constructed by the medial, lateral and upper wall through mechanical derivation. Theoretical mechanical analysis of the role of each side in maintaining the stability of the proximal femur: (1) the medial wall formed the oblique support of the proximal femoral cantilever structure, which greatly reduced the bending stress and deflection of the structure, (2) the lateral wall could effectively reduce the sliding and deflection of the femoral neck under physiological loads, (3) the upper wall acted as a connection between the medial and lateral edges of the proximal femur, making the medial and lateral structures of the proximal femur resist the bending moment caused by physiological loads.

Recovering From Hip Fracture according to the Principle of the Three-element Mechanical Theory

“The Three-element Mechanical Theory will be used to guide the surgical principles for the treatment of elderly hip fracture: taking into account the overall structure reconstruction of the three walls, reconstructing the mechanical triangular structure of the proximal femur and achieving the balance and minimization of internal fixation, fracture load distribution, and mechanical stability, and finally avoiding the occurrence of surgical failure,” according to Peifu Tang.

“In the treatment of hip fracture, invalidation of any unilateral reconstruction of the triangular structure of hip will result in structural instability, leading to the fixation failure. Based on this mechanical structure, we had designed a series of proximal femoral fracture fixation instruments and got satisfactory clinical results,” according to Dr. Licheng Zhang from the Chinese PLA General Hospital.

Hip fractures are serious injuries, and while full recovery is possible, it is not always achieved. For that reason, timely surgery guided by the Three-element Mechanical Theory is necessary, and hopefully, you or your loved one will be able to get back to all of the activities you enjoy.


[1] Peifu Tang, Hua Chen. Orthopaedic Trauma Surgery [M]. Springer, 2021.

[2] Li J, Zhang L, Zhang H, et al. Effect of reduction quality on post-operative outcomes in 31-A2 intertrochanteric fractures following intramedullary fixation: a retrospective study based on computerised tomography findings [J]. International Orthopaedics 2019, 43(8): 1951-1959.

[3] J Li, L Han, H Zhan, et al. Medial sustainable nail versus proximal femoral nail antirotation in treating AO/OTA 31-A2.3 fractures: Finite element analysis and biomechanical evaluation [J]. Injury 2019, 50(3): 648-656.

[4] J Li, S Tang, H Zhang, et al. Clustering of morphological fracture lines for identifying intertrochanteric fracture classification with Hausdorff distance-based K-means approach [J]. Injury 2019, 50(4): 939-949.

[5] H Chen, J Li, Z Chang, et al. Treatment of femoral neck nonunion with a new fixation construct through the Watson-Jones approach [J]. Journal of Orthopaedic Translation 2019, 19: 126-132.

[6] Tang PF. Establishment of three-element stabilization concept in proximal femur and its significance in treatment of femoral neck nonunion [J]. Chinese Journal of Orthopaedic Trauma 2020, 22(12): 1013-1018.

[7] Li JT, Zhang LC, Xu GX, et al. Effect of invalid reconstruction of proximal femoral triangular structure on failure of fracture surgery [J]. Chinese Journal of Orthopaedics 2020, 40(14): 928-935.

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