A new method for the treatment of scoliosis is described in which a metal system of rods and hooks is implanted, and distraction and compression forces applied, to correct the curve and stabilize the treated segments in the corrected position by skeletal fixation. The technique and principles of this method of treatment and a summary of the preliminary results are given.

JBJS classics: Treatment of scoliosis: Correction and internal fixation by spine instrumentation

Very few subjects in contemporary orthopaedic surgery have evoked as much controversy, thought, and opinion as that of when and how to optimally reconstruct the anterior cruciate ligament of the knee. Fueled by an annual incidence of acute rupture of the anterior cruciate ligament that has been estimated to be one in 3000 in the American population—approximately 95,000 new injuries each year196—and combined with the fact that more than 50,000 knees that have such an injury are reconstructed annually in the United States alone149, it is not surprising that there has been a virtual explosion of literature on this topic. During the last twenty years, more than 2000 scientific articles on the anterior cruciate ligament have been published, including numerous excellent reviews47,149,151,255,282,294 and textbooks72,89,145. It is a challenging task to attempt to synthesize these sources and to try to resolve the conflicts that are inherent in such a massive body of information. Although many relevant issues will continue to be debated until better basic-science and clinical information becomes available, a number of scientifically supported concepts can be identified within the existing knowledge base. This knowledge can help orthopaedic surgeons to understand the reasons for previous and current successes and failures of reconstruction of the anterior cruciate ligament, and it can help them to plan the care of patients who have an injury of the ligament.

In the present review, the current scientific understanding of reconstruction of the anterior cruciate ligament is discussed in a sequence based on the order in which clinical decisions are made. An overview of the normal function of the knee joint and the anterior cruciate ligament is followed by a discussion of decisions that must …

The science of reconstruction of the anterior cruciate ligament.

The neuromuscular function of the lower extremity in 40 normal and 100 anterior cruciate ligament-deficient volunteers was evaluated by physical examination, KT-1000 arthrometer measurements, isokinetic strength and endurance testing, subjective functional assessment, and an anterior tibial translation stress test. A specially designed apparatus delivered an anteriorly directed step force to the posterior aspect of the leg while anterior tibial translation was monitored and electromyographic signals were recorded at the medial and lateral quadriceps, medial and lateral hamstrings, and gastrocnemius muscles. Testing was done at 30 degrees of knee flexion with the foot fixed to a scale to monitor weightbearing, while the tibia remained unconstrained. Results indicate that muscle timing and recruitment order in response to anterior tibial translation are affected by anterior cruciate ligament injury. These alterations in muscle performance change with time from injury, correlate with an individual's physical activity level, affect subjective functional parameters, and are directly related to the degree of dynamic anterior tibial laxity seen with stress testing.

/pdf/neuromuscular-performance-in-normal-and-anterior-cruciate-1n02uz8147.pdf

Neuromuscular Performance in Normal and Anterior Cruciate Ligament-Deficient Lower Extremities

Failed anterior cruciate ligament (ACL) reconstruction presents a difficult clinical challenge. Successful revision ACL reconstruction depends on identifying the causes of failure and correcting technical or diagnostic errors. Failed ACL reconstruction may be either traumatic or atraumatic. Atraumatic failures may be attributable to technical errors, diagnostic errors, or failure of graft incorporation. Published outcomes of revision ACL reconstruction have been worse than for primary ACL reconstruction. The preoperative evaluation, surgical techniques, and clinical outcomes of revision ACL reconstruction are reviewed.

Current concepts review: revision anterior cruciate ligament reconstruction.

We analyzed mechanical tensile properties of 16 10-mm wide, full-thickness central parts of quadriceps tendons and patellar ligaments from paired knees of eight male donors (mean age, 24.9 years). Uniaxial tensile testing was performed in a servohydraulic materials testing machine at an extension rate of 1 mm/sec. Sixteen specimens were tested unconditioned and 16 specimens were tested after cyclic preconditioning (200 cycles between 50 N and 800 N at 0.5 Hz). Mean cross-sectional areas measured 64.6 +/- 8.4 mm2 for seven unconditioned and 61.9 +/- 9.0 mm2 for eight preconditioned quadriceps tendons and were significantly larger than those values of seven unconditioned and seven preconditioned patellar ligaments (36.8 +/- 5.7 mm2 and 34.5 +/- 4.4 mm2, respectively). Mean ultimate tensile stress values of unconditioned patellar ligaments were significantly larger than those values of unconditioned quadriceps tendons: 53.4 +/- 7.2 N/mm2 and 33.6 +/- 8.1 N/mm2, respectively. Strain at failure was 14.4% +/- 3.3% for preconditioned patellar ligaments and 11.2% +/- 2.2% for preconditioned quadriceps tendons (P = 0.0428). Preconditioned patellar ligaments exhibited significantly higher elastic modulus than preconditioned quadriceps tendons. Based on mechanical tensile properties analyses, the quadriceps tendon-bone construct may represent a versatile alternative graft in primary and revision anterior and posterior cruciate ligament reconstruction.

Mechanical Tensile Properties of the Quadriceps Tendon and Patellar Ligament in Young Adults

To better understand the role of preventive knee braces in injury prevention, a biomechanical study using fresh frozen cadaveric knees (N = 18) was conducted. Liga ment tensions and joint displacements were measured at static, nondestructive valgus forces as well as low- rate destructive forces. After quantifying and establish ing individual ligament contributions to valgus restrain ing function, knees were then braced with two different laterally applied preventive braces, the McDavid Knee Guard and the Omni Anderson Knee StabIer.The effects of lateral bracing were analyzed according to valgus force, joint line opening, and ligament tensions.Valgus applied forces, with or without braces, consis tently produced medial collateral ligament (MCL) disrup tions at ligament tensions surprisingly higher than the anterior cruciate ligament (ACL) and higher than or equal to the posterior cruciate ligament (PCL). Although large joint displacements were necessary for complete ligament failure, bundle disruption in t...

The biomechanics of lateral knee bracing Part I: Response of the valgus restraints to loading

In Part I of our study on lateral knee bracing, we evaluated brace effectiveness using cadaveric knees and two commercially available braces (McDavid and Omni). The results indicated that for low-rate dynamic valgus loading, neither brace provided significant pro tection against MCL injury. Also, four potentially ad verse effects were noted. The goals in Part II were to: 1) determine the clinical significance of brace induced MCL preload; 2) define the functional character of an "ideal" brace; 3) design and validate a surrogate knee model for testing brace effectiveness; and 4) determine brace performance under impact loading using the sur rogate knee and six commercially available brace types (manufactured by DonJoy, McDavid, Mueller, Omni Sci entific, Stromgren-Scott, and Tru-Fit). Knee braces, modified to measure varus/valgus bending force, were used to determine MCL preload effects in 13 human volunteers. An anatomically correct surrogate knee model, instrumented to measure ligament/tendon ten sion an...

The biomechanics of lateral knee bracing. Part II: Impact response of the braced knee.

Anterior displacement of the tibia during knee extension movement has been identified as a possible factor in anterior cruciate ligament (ACL) reconstruction failure due to the increased stress placed on the graft, leading to a creep response in the healing graft. Nineteen healthy subjects with a unilateral ACL deficiency were evaluated in an open and closed kinetic chain. A KT-1000 was used to measure anterior displacement of the tibia on the femur during isometric open and closed kinetic chain exercise at 30 and 60 degrees. An analysis of variance for repeated measures followed by Newman-Keuls multiple comparison tests were performed to determine the differences between the open and closed kinetic chain for the involved and uninvolved knee. Statistically significant differences were found when comparing the amount of anterior displacement between the open and closed kinetic chain for the involved and uninvolved knee at 30 and 60 degrees. Clinicians utilizing isometric exercise in rehabilitation of the anterior-cruciate-deficient and the anterior-cruciate-reconstructed patient should be aware of the increased amount of anterior tibial displacement when comparing open and closed kinetic chain exercise.

https://www.jospt.org/doi/pdf/10.2519/jospt.1997.25.1.49

A measurement of anterior tibial displacement in the closed and open kinetic chain

The osteocutaneous radial forearm free flap (OCRFFF) has not gained widespread popularity in mandibular reconstruction, primarily because of concerns about pathologic fracture of the weakened radius. This study examines the effectiveness of plate fixation of the radius bone after harvest of the OCRFFF as a mechanism to minimize donor-site morbidity and increase the usefulness of the OCRFFF. Matched pairs of fresh human cadaveric radius bones were used in this study. Two study groups were designed. The first group was used to define the amount of strength lost after a typical bone graft harvest. The second group was designed to demonstrate how much torsional strength was regained by the application of an orthopedic reconstruction plate. Statistically significant results were obtained for both groups. In group 1, the strength of the cut bones compared with that of the unaltered bones was significantly decreased by 82% (P = 0.016). In group 2, the cut bones reinforced with a plate were 75% stronger (P = 0.002) than the bones that were only cut. Although the radius bone is significantly weakened by the harvest of a graft, much of this strength can be regained with plate fixation of the radius. (Otolaryngol Head Neck Surg 2000;123:400-8.)

Torsional strength of the radius after osteofasciocutaneous free flap harvest with and without primary bone plating.

The purpose of this study was to measure the effect produced on canine patellar tendon of a 90 degree pretwist on the following mechanical properties: failure stress, failure strain, average elastic modulus, and strain energy density. Forty adult mongrel dog cadavers, killed for other studies, were used. Paired patellar tendons were isolated with patellar and tibial bone and the central 4.0-4.6 mm of tendon used for testing. Specimens were elongated to failure using a Materials Testing System (MTS). Only those paired specimens both failing in substance were analyzed. Eight paired specimens were analyzed, both with 0 degree twist, for right-left reproducibility. Thirty-two paired specimens were randomly assigned to four groups: right 0 degree/left 90 degree clockwise pretwist; right 0 degree/left 90 degree counterclockwise; left 0 degree/right 90 degree clockwise; left 0 degree/right 90 degree counterclockwise. No statistically significant differences were present between the paired untwisted specimens in any mechanical property. In the pretwisted specimens, there were statistically significant differences between the group left/clockwise and right/counterclockwise and the group left/counterclockwise and right/clockwise with respect to the mechanical properties failure stress, average elastic modulus, and strain energy density. No statistically significant differences were observed between the two groups for failure strain. For the canine patella-patellar tendon-tibia complex (PPTTC), the mechanical properties failure stress, average elastic modulus, and strain energy density are sensitive to both side (left/right) of PPTTC and direction (clockwise/counterclockwise) of pretwist. Pretwist of patellar tendon grafts in anterior cruciate ligament reconstruction may produce significant changes in their mechanical properties that vary with the direction of twist.

Gopal Jayaraman

Papers

The biomechanics of lateral knee bracing Part I: Response of the valgus restraints to loading

The biomechanics of lateral knee bracing. Part II: Impact response of the braced knee.

A measurement of anterior tibial displacement in the closed and open kinetic chain

Torsional strength of the radius after osteofasciocutaneous free flap harvest with and without primary bone plating.

Effects of pretwist on biomechanical properties of canine patellar tendon