Biomechanical and histological observations of the dog patellar tendon after removal of its central one-third

Soft Tissue Healing and its Impact on Rehabilitation

When soft tissue is injured, it must follow a complex healing process. The sports medicine specialist delivering care to an injured athlete should have an appreciation and understanding of the phases and timing of the healing process so that appropriate, efficient, and effective rehabilitation program may be established. This paper presents an overview of the chemical and cellular activity involved in soft tissue healing, with emphasis on those aspects that can be affected by a rehabilitation program. Outside factors commonly used in sports injury care and how they may influence tissue healing are addressed. Guidelines are presented for establishing a sports rehabilitation program based on the physiological effects of the healing process. Various aspects of a rehabilitation program must be carefully coordinated with the timing of tissue healing and designed in a logical sequence to permit successful rehabilitation of the injured athlete in an optimal and efficient manner.

Mechanical properties of the canine patellar tendon: some correlations with age and the content of collagen

Portions of the patellar tendon (PT) are currently used for autogenous and allogeneic reconstruction of a torn or damaged anterior cruciate ligament (ACL). Age-related changes in the mechanical properties of the PT may influence its use in this reconstruction procedure. Age-dependent changes in the PT were determined in the dog, which is often used to experimentally study this reconstruction. Tensile failure experiments were performed at 100% s-1 on patella-patellar tendon-tibia preparations from dogs aged 0.5-15 yr. The contents of collagen soluble and insoluble in pepsin were also measured at each age. Fifty-nine percent (16/27) of the preparations failed by avulsion at the patella, but neither the failure load nor the mode of failure were a function of age. Failure load and energy were higher for tendon substance failures compared to avulsions of bone from the patella. While a positive, linear correlation was measured between tensile modulus of the PT and age, the slope of regression was not significantly different from zero. The content of total collagen in the PT decreased significantly with age. The content of collagen insoluble in pepsin, however, increased with age and positively correlated with tensile modulus of the tendon. These results are different from those reported for the canine CCL, by others, which degenerates with age. Age-related changes in the mechanical properties of the canine PT are qualitatively similar to earlier, limited data on human patellar tendons.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term study of anterior cruciate ligament reconstruction for chronic instability using the central one-third patellar tendon and a lateral extraarticular tenodesis

Forty-four patients with symptomatic chronic anterior cruciate ligament instabilities that had been reconstructed with the central one-third patellar tendon and a lateral extraarticular iliotibial band tenodesis were studied at an average followup of 7 years (range, 4 to 10). The cases with associated medial, lateral, or posterior laxity were not included, nor were the cases with more than minimal preoperative degenerative changes. The average age at surgery was 21 years (range, 16 to 33). A postoperative cast was used for 4 weeks. Satisfactory objective stability, which was defined as a KT-1000 side-to-side difference of up to 5 mm at the manual maximum test, was obtained in 37 (84%) of the patients. In 25 patients (57%), stability was restored within normal limits (less than or equal to 3 mm). No deterioration of the KT-1000 stability was noted at two follow-up visits performed by the same examiner (at an average of 4 and 7 years). A return to high-risk sports was possible in 27 (62%) of the patients. Difficulties in regaining a complete range of motion were recorded in 5 (11%) of the patients. A flexion contracture of 5 degrees to 7 degrees was also found in 5 patients. Significant patellofemoral symptoms were present in 4 patients (9%). A 5% to 11% shortening of the patella tendon was observed in 14 (32%) of the knees, but did not correlate with patellar problems. Moderate radiographic changes were noted in eight patients (18%) at followup and correlated with meniscectomy and pain. Overall satisfactory results were obtained in this initial experience in 29 (66%) of the patients.(ABSTRACT TRUNCATED AT 250 WORDS)

A new technique of harvesting patellar tendon autografts for anterior cruciate ligament reconstruction

A new surgical technique to uniformly harvest the middle one-third of the patellar tendon for anterior cruciate ligament reconstruction is described. The technique uses a guide system of 8 templates of varying widths to guide the saw cuts and "collared," depth-controlled saw blades and drill bits to produce a standard cutting and drilling depth. This kind of template system lessens the risks of graft harvesting complications such as patella fracture, bone graft fragmentation, suture pull out, and judgment errors pertaining to graft depth, length, or width. The Patellar Tendon Graft Guide was used to obtain a patellar tendon graft in 65 patients. Fifty-nine arthroscopic-assisted and 6 open anterior cruciate ligament reconstructions were performed. Of the 65 grafts harvested, 63 consistently demonstrated bone portions 20 mm in length, 7 mm in depth, and a width corresponding to the template chosen (usually 10 mm). Two grafts supposed to be 10 mm in width turned out to be 9 mm in width because of a technique related problem.