Rehabilitation following anterior cruciate ligament (ACL) reconstruction has undergone a relatively rapid and global evolution over the past 25 years. However, there is an absence of standardized, objective criteria to accurately assess an athlete's ability to progress through the end stages of rehabilitation and safe return to sport. Return-to-sport rehabilitation, progressed by quantitatively measured functional goals, may improve the athlete's integration back into sport participation. The purpose of the following clinical commentary is to introduce an example of a criteria-driven algorithm for progression through return-to-sport rehabilitation following ACL reconstruction. Our criteria-based protocol incorporates a dynamic assessment of baseline limb strength, patient-reported outcomes, functional knee stability, bilateral limb symmetry with functional tasks, postural control, power, endurance, agility, and technique with sport-specific tasks. Although this algorithm has limitations, it serves as a foundation to expand future evidence-based evaluation and to foster critical investigation into the development of objective measures to accurately determine readiness to safely return to sport following injury.

https://www.jospt.org/doi/pdf/10.2519/jospt.2006.2222

Rehabilitation After Anterior Cruciate Ligament Reconstruction: Criteria-Based Progression Through the Return-To-Sport Phase

Study Design: Controlled single-group pretest/posttest design. Objective: The purpose of this study was to determine if a 6-week neuromuscular training program designed to decrease the incidence of anterior cruciate ligament (ACL) injuries would improve single-limb postural stability in young female athletes. We hypothesized neuromuscular training would result in an improvement in postural stability, with the greatest improvement taking place in the medial-lateral direction. Background: Balance training has become a common component of programs designed to prevent ACL injury. Rehabilitation programs can improve postural stability following ACL injury and reconstruction; however, there is limited information available which quantifies improvement of postural stability following neuromuscular training designed to prevent ACL injuries in a healthy population. Methods and Measures: Forty-one healthy female high school athletes (mean age, 15.3 years; age range, 13–17 years) participated in this study. Single-l...

https://www.jospt.org/doi/pdfplus/10.2519/jospt.2004.34.6.305

Neuromuscular training improves single-limb stability in young female athletes.

Proprioception and neuromuscular control of the knee are compromised after ligament injury and must be regained if the athlete is to return to high level sports at a normal injury risk level. The anterior cruciate ligament deficient and reconstructed knee will be used as a model to describe differences in proprioception and neuromuscular control to those of an uninjured knee. The purpose of the current review is threefold. First, the basic science of proprioception and neuromuscular control specific to the knee will be summarized and reviewed. The review will include an overview of terminology, neurophysiology, and the effects of injury on the function of both lower limbs. Second, tools used for assessment and rehabilitation of proprioceptive deficits will be evaluated. Specific rehabilitation procedures that incorporate prophylactic conditioning that focus on transitioning the injured athlete back into sport will be presented. Finally, the literature with respect to gender variation in proprioception and neuromuscular control will be evaluated. The goal of the current review is to provide the clinician and the clinical scientist with sufficient background information for the development of quantitative methods to evaluate a patient's functional capacity and to assist in preventative, preoperative, and postoperative decision-making strategies.

/pdf/strategies-for-enhancing-proprioception-and-neuromuscular-1rmzidlfer.pdf

Strategies for enhancing proprioception and neuromuscular control of the knee.

Returning athletes to competition following injury often creates a dilemma for athletic trainers and team physicians. Most clinicians gather as much data as possible before deciding whether to return an athlete to competition following injury. The status of the postural control system and balance is important for certain pathologies and therefore should be considered in these clinical decisions. As more high-tech balance systems become available, it is important for clinicians to understand not only what is available but what these devices measure. This paper will review the relationship between the postural control system and the kinetic chain, traditional and contemporary techniques for assessing balance, and ways in which clinicians can bridge the gap between balance research and clinical practice.

/pdf/research-and-clinical-applications-of-assessing-balance-4s8nslji12.pdf

Research and Clinical Applications of Assessing Balance

OBJECTIVE: To compare postural stability, single-leg hop, and isokinetic strength measurements in subjects after anterior cruciate ligament (ACL) reconstruction with an age- and activity-matched control group. DESIGN AND SETTING: Subjects reported to a sports medicine/athletic training research laboratory for testing. Subjects reported for one testing session for a total test time of 1 hour. SUBJECTS: Twenty subjects with ACL reconstructions (ACLRs) and 20 age- and activity-matched controls were selected to participate in this study. An arthroscopically assisted central one-third bone-patellar tendon procedure was used to repair the ACLs. MEASUREMENTS: We measured concentric and eccentric peak torque (Nm) measurements of the knee extensors and flexors at 120 degrees and 240 degrees /second on an isokinetic dynamometer. Unilateral and bilateral dynamic postural stability was measured as a stability index in the anterior-posterior and medial-lateral planes with the Biodex Stability System. We tested single-leg hop for distance to measure objective function. RESULTS: We found no significant difference between the ACLR and control subjects for stability index or knee-flexion peak torque scores. On the single-leg hop for distance, the ACLR subjects hopped significantly shorter distances with the involved limb than the uninvolved limb. Furthermore, the ACLR subjects' single-leg hop distance was significantly less when the involved limb was compared with the control-group matched involved limb, and the ACLR subjects performed significantly better when the uninvolved limb was compared with the control-group matched uninvolved limb. The ACLR subjects produced significantly greater torque in the uninvolved leg than in the involved leg. In addition, the peak torque was significantly less for the involved limb in the ACLR group when compared with the matched involved limb of the control group. CONCLUSIONS: After ACLR (mean = 18 +/- 10 months), single-leg hop-for-distance scores and quadriceps strength were not within normal limits when compared with the contralateral limb. Our results suggest that bilateral and single-limb postural stability in the ACLR group was not significantly different than the control group at an average follow-up of 18 months after surgery.

/pdf/strength-functional-outcome-and-postural-stability-after-4qmuw0mp5o.pdf

Strength, Functional Outcome, and Postural Stability After Anterior Cruciate Ligament Reconstruction.

In two rare cases with avulsion of the hamstring muscles from the ischial tuberosity without fracture of the ischium, the clinical features were: (1) sudden onset of pain in the buttock; (2) difficulty on standing after trauma; (3) a palpable defect and tenderness on the area distal from the ischial tuberosity; and (4) weakness of flexion of the knee with a loss of normal outline of the hamstring muscles on the dorsal aspect of the knee. There was no roentgenologic evidence of fracture of the ischium. Surgical repair with reattachment of avulsed muscles to the ischium and proximal tendinous sheaths of the muscles restored function or corrected deformity.

Avulsion of the hamstring muscles from the ischial tuberosity. A report of two cases.

The standing balance of 11 functionally stable and 15 functionally unstable knees in patients with chronic anterior cruciate ligament (ACL)-deficient joints was studied by means of stabilometry. All the patients had participated in sports on a competitive level before injury, and functional stability was defined as full return, without giving way, to the same sport at the same level as before injury. Forty physically active volunteers were studied as the reference group. When compared with the reference group, an impaired standing balance was found in the functionally unstable patients but not in the functionally stable patients. The results indicate that stabilometry is a useful method for evaluating knee functional instability objectively in competitive athletes with chronic ACL-deficient knees.

A Stabilometric Technique for Evaluation of Functional Instability in Anterior Cruciate Ligament-deficient Knee

We present a case of bilateral osteonecrosis of the patella in a patient during steroid therapy and demonstrate the radiological, arthroscopic, and histological features. Osteonecrosis of the patella should be considered as a possible cause of knee pain in patients receiving steroid therapy.

Steroid-related bilateral osteonecrosis of the patella

The purpose of this study was to investigate the relationship between the appearance of basal lamina components (Type IV collagen and laminin) and the development of cartilage canals. In the distal femoral epiphyses from developing rats, the distribution of basal lamina components in the cartilage canal was examined immunohistochemically. The formation of cartilage canals from the perichondrium was first observed on the fifth day after birth. By Day 8, a few cartilage canals penetrated the epiphyseal cartilage and considerably increased in size and length. By light microscopic immunohistochemistry, reticular structures stained with anti-Type IV collagen and antilaminin antibodies were observed in the cartilage canals. In the early development of cartilage canals, however, immunostaining by anti-Type IV collagen antibodies was weaker than that by antilaminin antibodies. In eight-day-old rats, the laminin-positive reticular structures were more densely colored and more widely distributed in the canal than the Type IV collagen-positive ones. Type IV collagen was found around the endothelial cells of the developing capillaries by electron microscopic immunohistochemistry. Laminin was observed in the cytoplasm of the mesenchymal fibroblastic cells and their pericellular matrix as well as in the capillary basal lamina. These immunohistochemical electron microscopic observations can explain the differences that are observed in Type IV collagen and laminin immunostaining patterns as cartilage canals develop. Laminin synthesized by the mesenchymal fibroblastic cells may promote the migration and the outgrowth of endothelial cells in the formation of cartilage canals.

Immunohistochemical localization of basal lamina components in the developing rat epiphyseal cartilage canals.

The effect of enforced running on the morphological characteristics of the fibroblasts and on the distribution of the collagen fibril diameter in the anterior cruciate ligament of bipedal rats was examined by electron microscopy. Twelve bipedal rats were divided into two groups of equal numbers: (1) those without exercise, and (2) those with enforced exercise on a treadmill for four weeks. Ninety percent of the fibroblasts in the rats without exercise were ovoid-shaped with a round nucleus, whereas eighty-one percent of those in the rats with exercise were spindle-shaped with indented nucleus. There was a significant difference in the ratios of ovoid-shaped to spindle-shaped cells between the two groups (p < 0.05). There was an increased number of rough surfaced endoplasmic reticula and lysosomal vesicles in the fibroblasts of the rats with exercise. The collagen fibril diameters of the rats with exercise varied in size from 20 to 120 nm, while those of the rats without exercise were uniform in size, mostly between 50-80 nm. Mean collagen fibril diameter was 70.8 +/- 16.6 nm in the rats without exercise, and 66.6 +/- 21.9 nm in the exercised rats. This difference was significant (p < 0.05). These electron-microscopical findings indicate an increased collagen metabolism in the anterior cruciate ligament of rats with enforced running.

Koichi Kai

Papers

Avulsion of the hamstring muscles from the ischial tuberosity. A report of two cases.

A Stabilometric Technique for Evaluation of Functional Instability in Anterior Cruciate Ligament-deficient Knee

Steroid-related bilateral osteonecrosis of the patella

Immunohistochemical localization of basal lamina components in the developing rat epiphyseal cartilage canals.

Ultrastructural changes of collagen fibers in the anterior cruciate ligament of bipedal rats after enforced running.