Pathological conditions affecting the hip and knee joints occupy a particular place amongst the important orthopaedic entities affecting the extremities. On the one hand they are relatively frequent and on the other they mean for the patient limitation of his ability to walk, because of their considerably detrimental effects. A purposeful basic treatment of these joint diseases (and here osteoarthritis takes pride of place) is only possible if it stems from a reliable biomechanical analysis of the normal and patho logical stressing of the joint in question. Whilst the situation in the hip can be considered to be fundamentally clarified, a com prehensive representation of the knee is still lacking particularly when taking into account the latest knowledge of biomechanics. Recently our concepts of the kinematics of the knee have been completely changed, but the clinically important question of articular stressing remains unanswered. Dr. Maquet has carried out pioneer work in this field for some years in adapting, by analogy, to the knee joint, principles already accepted for the hip joint. Since the knee is not a ball and socket joint, a complicated problem arises for which new thoughts are necessary. The results of the numerous operations carried out by Dr. Maquet according to the biomechanical con siderations, demonstrate that his thinking is fundamentally correct. Above all, it is here again proven (as earlier in the case of the hip) that healing of osteoarthritis depends decisively on reducing and evenly distributing joint pressure.
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1. Aims and Limitations of the Work.- II Review of the Literature.- III Methods.- I. Mathematical Analysis.- II Experiments on Anatomical Specimens.- III Photoelastic Models.- A. Theoretical Basis.- B. Historical.- C. Application and Limitation of the Photoelastic Technique.- IV. Chnical and Radiological Material.- IV. Mechanics of the Knee.- I. Load and Mechanical Stresses.- A. Concept of Load and Stresses. Rigid Models.- B. Articulated Models.- 1. Forces.- 2. Contact Stresses.- II Mechanical Stress in the Knee.- A. Forces Exerted on the Knee.- 1. Force Exerted on the Knee During Symmetrical Stance on Both Legs.- 2. Forces Exerted on the Knee in Standing on One Limb.- a) Coronal Plane.- b) Sagittal Plane.- 3. Forces Exerted on the Knee During Gait.- a) Displacement of the Centre of Gravity S7.- b) Forces of Inertia Due to the Accelerations of S7.- c) Force P Exerted on the Knee by the Partial Mass S7 of the Body.- d) Location in Space of Point G Which Lies Centrally on the Axis of Flexion of the Knee.- e) Situation of the Knee in Relation to the Partial Centre of Gravity S7.- f) Distance a Between the Line of Action of Force P and Poin G.- g) Muscular and Ligamentous Forces Balancing Force P.- ?) Stylization.- ?) Calculation.- ?) Further Development.- h) Curves Illustrating the Forces Transmitted Through the Femoro-Tibial Joint.- i) Patello-Femoral Compressive Force.- B. Weight-Bearing Surfaces of the Femoro-Tibial Joint.- 1. Technique.- 2. Results.- C. Contact Articular Stresses.- III. Conclusion.- V. Vie Pathomechanics of Osteoarthritis of the Knee.- I. Theoretical Analysis of the Causes of Knee Osteoarthritis.- A. Medial Displacement of Force R.- B. Lateral Displacement of Force R.- C. Unstable Knees.- D. Evolution of the Maximum Stress in Relation to Several Parameters.- 1. Varus or Valgus Deformity.- a) Magnitude and Line of Action of R.- b) Articular Compressive Stresses.- 2. Strengthening or Weakening of the Muscular Force L.- 3. Cumulative Effect of a Change of the Force L and a Deformity of the Leg.- 4. Modification of Force P.- 5. Horizontal Displacement of S7 in the Coronal Plane.- 6. Conclusion.- E. Posterior Displacement of Force R.- F. Increase of the Patello-Femoral Compressive Force.- G. Lateral Displacement of the Patello-Femoral Compressive Force.- II. Radiographic Examination of the Osteoarthritic Knee with Demonstration of the Effect of Changes in the Compressive Force on the Stress Distribution.- A. Demonstration of Joint Stresses.- 1. A.-P. View.- 2. Lateral View.- 3. The Patello-Femoral Groove.- B. Utility of X-Rays in the Standing Position.- III. The Use of Photoelastic Models to Illustrate How the Position of Compressive Femoro-Tibial and Patello- Femoral Forces Affects the Distribution of Articular Stresses.- A. Femoro-Tibial Joint.- 1. Normal Load, Well Centred.- 2. Normal Load, Off Centre.- 3. Inclined Load, Well Centred.- 4. Inclined Load, Off Centre.- B. Patello-Femoral Joint.- 1. Directional Distribution of the Stresses.- 2. Quantitative Distribution of the Stresses.- IV. Osteoarthritis of the Knee of Mechanical Origin.- VI Mechanisms which Instinctively Reduce Stress in the Knee.- I. Effects of Limping.- II. Use of a Walking Stick.- III Comment and Conclusion.- VII Biomechanical Treatment of Osteoarthritis of the Knee.- I. Principles of Biomechanical Treatment.- II. Biomechanical Treatment of Osteoarthritis of the Knee.- A. Correction of Fixed Flexion Deformity.- 1. Principle.- 2. Operative Technique.- a) Capsulotomy Alone.- b) Capsulotomy Associated with Other Procedures.- 3. Results.- B. Anterior Displacement of the Patella Tendon.- 1. Principle.- 2. Operative Procedures.- a) Anterior Displacement of the Tibial Tuberosity by Elevating the Tibial Crest.- b) Upper Tibial Osteotomy.- 3. Results.- C. Recentring the Load.- Principle.- Planning-Preoperative Drawing.- 1. Osteoarthritis of the Knee with Varus Deformity.- a) Accurate Estimation of Overcorrection.- b) Operative Procedures.- ?) Techniques Used Prior to 1968.- ?) Technique for the Barrel-Vault Osteotomy for Varus Deformity.- ?) Cases Requiring a Derotation of the Leg.- 2. Osteoarthritis with Valgus Deformity.- a) Necessity of Overcorrection and Indication for the Type of Osteotomy.- b) Proximal Tibial Osteotomy.- ?) Previous Techniques.- ?) The Barrel-Vault Osteotomy for Valgus Deformity.- c) Distal Femoral Osteotomy.- ?) Previous Techniques.- ?) Distal Femoral Osteotomy with Fixation by Four Steinmann Pins and Two Compression Clamps.- 3. Osteoarthritis with Genu Recurvatum.- 4. Osteoarthritis of the Knee Due to a Distant Deformity.- 5. Widespread Osteoarthritis without Deformity.- D. Critical Analysis of Patellectomy.- E. Operative Indications.- F. Analysis of the Results.- 1. Anterior Displacement of the Patella Tendon.- 2. Osteotomies for Osteoarthritis with Varus Deformity.- 3. Osteotomies for Osteoarthritis with Valgus Deformity.- 4. Correction of a Distant Deformity.- G. Complications.- 1. General Complications.- 2. Local Complications.- H. Comment About the Treatment.- VIII Conclusions.- Appendix. Remarks About the Accuracy of the Calculation of Forces and Stresses in the Knee-Joint.- A. Introduction.- 1. The Weights.- 2. Stylization.- 3. The Laws.- 4. Direct Personal Measurements.- B. Analysis of the Influence of the Variation of Time Between Two Successive Phases.- C. Influence of a Systematic Error of 10% in All the Measurements of Braune and Fischer.- D. Theory of Cumulated Errors, a Variation of 0.2 mm Being Assumed for All the Measurements.- E. Influence of a Variation of the Weight-Bearing Surfaces.- F. Influence of an Error in Estimating r.- G. Direct Measurements.- H. Conclusions.- References.