Hip joint biomechanics in those with and without post-traumatic knee osteoarthritis after anterior cruciate ligament injury.

BACKGROUND: Anterior cruciate ligament injury results in altered kinematics and kinetics in the knee and hip joints that persist despite surgical reconstruction and rehabilitation. Abnormal movement patterns and a history of osteoarthritis are risk factors for articular cartilage degeneration in additional joints. The purpose of this study was to determine if hip joint biomechanics early after anterior cruciate ligament injury and reconstruction differ between patients with and without post-traumatic knee osteoarthritis 5years after reconstruction. The study's rationale was that individuals who develop knee osteoarthritis after anterior cruciate ligament injury may also demonstrate large alterations in hip joint biomechanics. METHODS: Nineteen athletes with anterior cruciate ligament injury completed standard gait analysis before (baseline) and after (post-training) extended pre-operative rehabilitation and at 6months, 1year, and 2years after reconstruction. Weightbearing knee radiographs were completed 5years after reconstruction to identify medial compartment osteoarthritis. FINDINGS: Five of 19 patients had knee osteoarthritis at 5years after anterior cruciate ligament reconstruction. Patients with knee osteoarthritis at 5years walked with smaller sagittal plane hip angles (P: 0.043) and lower sagittal (P: 0.021) and frontal plane (P: 0.042) external hip moments in the injured limb before and after reconstruction compared to those without knee osteoarthritis. INTERPRETATION: The current findings suggest hip joint biomechanics may be altered in patients who develop post-traumatic knee osteoarthritis. Further study is needed to confirm whether the risk of non-traumatic hip pathology is increased after anterior cruciate ligament injury and if hip joint biomechanics influence its development.

Laxity, instability, and functional outcome after ACL injury: copers versus noncopers.

PURPOSE: The purpose of this study was to determine the relationship among laxity, quadriceps strength, instability, and function in subjects with complete rupture of the anterior cruciate ligament (ACL) who compensate well for the injury (copers) and those who require surgical stabilization (noncopers). METHODS: Forty-five patients with unilateral ACL rupture (confirmed via arthroscopy or magnetic resonance imaging (MRI) and arthrometer measurements) participated in this study. Subjects were divided into two groups: copers (N = 12), and subacute noncopers (N = 18) and chronic noncopers (N = 15). All copers had returned to all preinjury activity (including index sport) without limitation. Maximum manual anterior tibiofemoral laxity measurements, quadriceps femoris muscle strength measurements, and a series of hop tests were performed. Lysholm Scale, Knee Outcome Survey (KOS), global rating of knee function, and the International Knee Documentation Committee (IKDC) form were completed. RESULTS: There was no significant difference in laxity between copers (X = 5.5+/-2.7 mm) and noncopers (chronic, X = 5.1+/-2.8 mm and subacute, X = 4.2+/-2.2 mm) or in IKDC scores among the groups. The copers, however, scored significantly better than the chronic and subacute ACL-deficient subsets on all other measures. Measurements of laxity were not correlated to any functional outcome measure or to episodes of instability. CONCLUSIONS: Copers were not different in any meaningful way from the noncopers before injury, had equal or greater side-to-side laxity differences, and functioned normally. A battery of tests was identified that accurately discriminated noncopers from copers even early after injury. Thus, measurements of laxity alone are insufficient for determining functional status after ACL injury.

Orthotic treatment of sesamoid pain.

The cause of pain and tenderness beneath the first metatarsal in an athlete is often very difficult to determine. When the symptoms originate from the sesamoid bone, exact diagnosis of the pathologic process may not be necessary in order to institute effective treatment. In this retrospective study, 8 of 10 athletes with this problem were successfully treated with custom-fitted orthoses which relieve sesamoid pain. The major benefit of this method of treatment is that it enables an athlete to continue participation without loss of valuable practice and competition time.

Upper extremity weight-training modifications for the injured athlete. A clinical perspective.

The ability of the health care professional to make correct decisions about the progression of weight-training is critical to the rehabilitation process. The purpose of this article is to describe our approach to modification of weight-lifting techniques using the injured shoulder as a model. Additionally, the impact of various upper extremity weight-training techniques on healthy athletes is discussed. The effects of grip, hand spacing, bar trajectory, and start and finishing positions on microtraumatic injury and return to weight-training activities after injury are considered. Several weight-training functional progressions for common multijoint exercises (such as bench press, shoulder press, power clean) are presented. Adaptations for periodization are also presented for implementation in the rehabilitation sequence. The weight-training modifications described in this paper will assist the health professional to safely return athletes to the weight room after shoulder injury.

Development of a distance-based interval throwing program for Little League-aged athletes.

We developed a distance-based interval throwing program for Little League-aged athletes (9 to 12 years) to be used in training and rehabilitation. The timing and repetition parameters were developed from data collected during 400 innings of organized baseball during a single season, and short toss distance from Little League rules for field dimensions. There were 1022 boys from organized baseball teams in the four studies. Maximal distance and speed measurements were recorded for 853 boys. We developed a mathematical model from these data to predict maximal throwing distance from maximal throwing speed. This model was then tested on a second sample of 114 players. We compared the predicted distance with the actual maximal throwing distance; the correlation coefficient was 0.92. Forty players aged 9 to 12 participated in a study to assess degradation of speed and distance. The average variability of the speed was small (< 5 mph), but the variability in distance was large (22.4 feet). Fifteen boys then threw the entire throwing program as designed. These results show that healthy young athletes can be expected to be able to throw the predicted value of this practical progressive interval throwing program for Little League-aged athletes. The appropriate program can be assigned from age and known preinjury pitch speed.

The efficacy of perturbation training in nonoperative anterior cruciate ligament rehabilitation programs for physical active individuals.

BACKGROUND AND PURPOSE: Treatment techniques involving perturbations of support surfaces may induce compensatory muscle activity that could improve knee stability and increase the likelihood of returning patients to high-level physical activity. The purpose of this study was to determine the efficacy of augmenting standard nonoperative anterior cruciate ligament (ACL) rehabilitation programs with a perturbation training program. SUBJECTS: Twenty-six patients with acute ACL injury or ruptures of ACL grafts participated in the study. Subjects had to have a unilateral ACL injury, be free of concomitant multiple ligament or meniscal damage requiring surgical repair, and pass a screening examination designed to identify patients who had the potential to return to high-level physical activity with nonoperative treatments. Subjects also had to be regular participants in level I activities (eg, soccer, football, basketball) or level II activities (eg, racquet sports, skiing, construction work). METHODS: Subjects were randomly assigned to either a group that received a standard rehabilitation program (standard group) or a group that received the standard program augmented with a perturbation training program (perturbation group). Treatment outcome was determined from scores on the Knee Outcome Survey's Activities of Daily Living Scale (ADLS) and Sports Activity Scale, a global rating of knee function, scores on a series of single-limb hop tests, measurements of maximum isometric quadriceps femoris muscle force output, and the group frequency of unsuccessful rehabilitation. Unsuccessful rehabilitation was defined as the occurrence of an episode of giving way of the knee or failure to maintain the functional status of a rehabilitation candidate on retesting. RESULTS: More subjects had unsuccessful rehabilitation in the standard group compared with the perturbation group. There was a within-group x time interaction for the ADLS, global rating of knee function, and crossover hop test scores. These scores decreased from posttraining to the 6-month follow-up for the standard group. CONCLUSION AND DISCUSSION: Although both the standard program and the perturbation training program may allow subjects to return to high-level physical activity, the perturbation training program appears to reduce the risk of continued episodes of giving way of the knee during athletic participation and allows subjects to maintain their functional status for longer periods.

1998 Basmajian Student Award Paper: Movement patterns after anterior cruciate ligament injury: a comparison of patients who compensate well for the injury and those who require operative stabilization.

The purpose of this study was to describe kinematic and kinetic differences between a group of ACL deficient subjects who were grouped according to functional ability. Sixteen patients with complete ACL rupture were studied; eight subjects had instability with activities of daily living (non-copers) and eight subjects had returned to all pre-injury activity without limitation (copers). Three-dimensional joint kinematics and kinetics were collected from the knee and ankle during walking, jogging and going up and over a step. Results showed that both groups mitigated the force with which they contacted the floor but non-copers consistently demonstrated less knee flexion in the involved limb. The copers used joint kinematics similar to those of their uninvolved knees and similar to knee motions reported in uninjured subjects. The reduced knee motion in the involved knee of the non-copers did not correlate directly with quadriceps femoris muscle weakness. The data suggest that the non-copers utilize a stabilization strategy which stiffens the knee joint which not only is unsuccessful but may lead to excessive joint contact forces which have the potential to damage articular structures. The copers use a strategy which permits normal knee kinematics and bodes well for joint integrity.

The classification of knee ligament instability.

In summary, this classification and the clinical tests that accompany it are presented to help clarify a commonly used language for these instabilities. The clinical examination of the knee is based on the anatomy; if one grasps the anatomy, functions, and rotations, one can comprehend the knee joint.

Biomechanical evidence supporting a differential response to acute ACL injury.

OBJECTIVE: To describe movement patterns in people with complete anterior cruciate ligament rupture objectively identified as good candidates for non-operative management of the injury. DESIGN: Involved side kinematics and kinetics were compared to the uninvolved side and to uninjured subjects. BACKGROUND: High-level athletes with anterior cruciate ligament rupture and poor dynamic stability (non-copers) have movement alterations, including less knee flexion and a decreased internal knee extensor moment during loading response, that are not seen in those with excellent knee stability (copers). Our screening exam can identify people with good rehabilitation potential for non-operative management of anterior cruciate ligament injury (potential copers), but the movement strategies of these individuals are unknown. METHODS: Sagittal plane kinematics and kinetics during the stance phase of walking and jogging were collected from 11 subjects who had an acute anterior cruciate ligament rupture and met the criteria of the screening exam, and were compared to 10 uninjured subjects, who we studied previously. Variables were those in which non-copers differed from uninjured subjects. RESULTS: The potential copers flexed their involved knee less than uninjured subjects and their uninvolved side during walking. Potential copers, compared to uninjured subjects, also had a lower vertical ground reaction force during loading response, a lower knee support moment, and an increased ankle support moment during walking. In jogging, the involved knee angle at initial contact was more extended compared to uninjured subjects, and the amount of knee flexion was less than the uninvolved side. No differences in kinetics were present during jogging. CONCLUSIONS: This study provides evidence that the potential copers identified by the screening examination have movement patterns that are consistent with people who have more knee stability than non-copers. RELEVANCE: Although potential copers have developed some characteristics of a successful stabilization strategy, the presence of kinematic alterations indicates that they may benefit from training programs designed to enhance dynamic knee stability.

Performance profile-directed simulated game: an objective functional evaluation for baseball pitchers*.

To objectively evaluate the function of the throwing shoulder after an injury, a preinjury performance profile should have been recorded and a simulated game based upon this profile be established for comparison. The performance profile must include a strength or power component (fastball velocity), an accuracy component (fastball-for-strike percentage), and an endurance component (the decrease in fastball velocity per inning). The simulated game requires a specific number of innings, a specific number of pitches per inning, a pitch selection ratio, a rest interval between innings, and a means to record the data. This information is not available in most circumstances. The authors have collected data from 98 starting pitchers in the National Baseball League from 1983 through 1985 to develop a profile for those pitchers lacking preinjury performance profiles. Since 1983, in 486 games, 145,886 consecutive pitches were logged using a custom data form and entered into an IBM- 360 computer. Based upon the summation of the performance profiles of these pitchers, a simulated game should be 61/3 + 1 l/3 innings with 15 + 2.4 pitches per inning. The interval between innings pitched should be a minimum of 9 minutes and one should expect a 2% or 1.5 mph decrease in the fastball velocity from the first through the sixth innings with a fastball-for-strike percentage of 64%. While this is a study of major league starting pitchers, the concept of a preinjury performance profile to define full rehabilitation is applicable from the Babe Ruth league through professional baseball. J Ortho Sports Phys Ther 1987;9(3):101-105.

Proposed practice guidelines for nonoperative anterior cruciate ligament rehabilitation of physically active individuals.

Nonoperative management of anterior cruciate ligament (ACL) rupture has not been a successful option for those who participate in high-level physical activity. However, there are instances when patients may want to attempt to return to physically demanding activities with nonoperative rehabilitation for an ACL injury. The purpose of this commentary is to describe guidelines for nonoperative management of physically active individuals with ACL injuries who wish to return to preinjury levels of physical activity. The guidelines are based on the results of 2 clinical studies that improved the overall success of nonoperative management of physically active individuals with ACL ruptures. A decision-making process for selecting appropriate candidates for nonoperative management (rehabilitation candidates) is described. Individuals are classified as rehabilitation candidates if they have no concomitant ligament or mensical damage associated with the ACL injury, have a unilateral ACL injury, and meet all 4 of the following criteria: (1) timed hop test score of 80% or more of the uninjured limb, (2) Knee Outcome Survey Activities of Daily Living Scale score of 80% or more, (3) global rating of knee function of 60% or more, and (4) no more than 1 episode of giving way since the incident injury to the time of testing. Individuals meeting the criteria of a rehabilitation candidate undergo an intensive rehabilitation program before returning to high-level activity. The rehabilitation program consisting of lower extremity muscle strength training, cardiovascular endurance training, agility and sport-specific skill training, and a training program using balance perturbations is described.

Limb-threatening injuries in sport.

It is the closed gross deformity of the knee with vascular compromise that most commonly leads to amputation. This algorithm is offered as an approach to this problem with great medical and legal ramifications. Compartment syndrome about the elbow and foot can be avoided if the signs and symptoms are recognized and the fascial compartments released.

Sports injuries and adolescent athletes.

A one-year study was undertaken investigating adolescent sports injury experiences at a major sports clinic in the state of Delaware. A total of 619 athletes sustained 870 injuries, for an overall injury rate of 1.4 injuries per athlete. The largest number of injuries was recorded in football (40.2 percent), followed by boys' soccer, wrestling, baseball and girls' basketball. Severity of injury was measured by the number of days lost per injury. Cheerleading had the highest average days lost per injury (28.8), followed by girls' basketball, wrestling, boys' cross-country and girls' tennis. Inflammation, fractures and dislocations comprised 50.6 percent of all the injuries, while 50.5 percent of the injuries were located in the knee, thigh, and shoulder. Twenty-seven of the 870 injuries required surgery.

A decision-making scheme for returning patients to high-level activity with nonoperative treatment after anterior cruciate ligament rupture.

This report describes the development and current use of decision-making criteria for returning patients to high-level physical activity with nonoperative management of anterior cruciate ligament ruptures, and presents the results of treatment for patients who met our criteria as candidates for nonoperative rehabilitation and attempted to return to high-level physical activity with nonoperative management. The screening examination consists of four one-legged hop tests, the incidence of knee giving-way, a self-report functional survey, and a self-report global knee function rating. We screened 93 consecutive patients with acute unilateral anterior cruciate ligament rupture, classifying them as either candidates (n = 39, 42%) or noncandidates (n = 54, 58%) for nonoperative management. Of the 39 rehabilitation candidates 28 chose nonoperative management and returned to preinjury activity levels, 22 of whom (79%) returned to preinjury activity levels without further episodes of instability or a reduction in functional status. No patient sustained additional articular or meniscal damage as a result of rehabilitation or return to activity. The decision-making scheme described in this study shows promise in determining who can safely postpone surgical reconstruction and temporarily return to physically demanding activities. Continued study to refine and further validate the decision-making scheme is recommended.

Dynamic stability after ACL injury: who can hop?

Single-leg hops are used clinically to assess knee function in patients following anterior cruciate ligament (ACL) rupture and reconstruction. Researchers study ACL-deficient individuals in order to identify movement strategies in the absence of a major knee stabilizer, thereby providing information to clinicians regarding treatment options. Single-leg hops represent an activity which places higher demands on the knee than walking or jogging. Hops are thought by some to represent demands that are more comparable to those found during high level sports. Therefore hopping might provide more information about knee stability during dynamic activities than less strenuous activities. This paper reflects one component of a larger study involving comparisons of joint motions and muscle activity patterns in uninjured individuals (n=10) and two groups of athletes who had complete ACL ruptures; one group had substantial knee instability (noncopers, n=10), and the other had no signs of knee instability (copers, n=11). In this paper we report the findings from the single-leg hop activity. The results indicate that coper subjects move in a manner nearly identical to uninjured persons. Kinetic data suggest that copers stabilize their knees with greater contributions from the ankle extensor muscles. Muscle activity data demonstrate that there is no reduction in quadriceps femoris activity in the coper subjects. In the group of ten subjects with knee instability (noncopers) who participated in the overall study involving walking, jogging, hopping, and a step activity only four were willing to hop. Work in our laboratory has established that when high level athletes rupture their ACL, the majority of them cannot return to high level sports. The small number of noncopers in this study who were willing to hop supports our previous findings. Those noncopers who did hop displayed reduced knee range of motion and external knee flexion moments, a movement strategy remarkably similar to that found during other activities. Neither the copers nor the noncopers showed evidence that quadriceps activation was diminished.

Dynamic stability in the anterior cruciate ligament deficient knee.

Some individuals can stabilize their knees following anterior cruciate ligament rupture even during activities involving cutting and pivoting (copers), others have instability with daily activities (non-copers). Movement and muscle activation patterns of 11 copers, ten non-copers and ten uninjured subjects were studied during walking and jogging. Results indicate that distinct gait adaptations appeared primarily in the non-copers. Copers used joint ranges of motion, moments and muscle activation patterns similar to uninjured subjects. Non-copers reduced their knee motion, and external knee flexion moments that correlated well with quadriceps strength. Non-copers also achieved peak hamstring activity later in the weight acceptance phase and used a strategy involving more generalized co-contraction. Both copers and non-copers had high levels of quadriceps femoris muscle activity. The reduced knee moment in the involved limbs of the non-copers did not represent "quadriceps avoidance" but rather represented a strategy of general co-contraction with a greater relative contribution from the hamstring muscles.