Lonnie Paulos

Knee rehabilitation after anterior cruciate ligament reconstruction and repair

The purpose of this paper is to present the specifics and rationale of our postoperative rehabilitation pro gram after anterior cruciate ligament (ACL) recon struction and compare it with an international survey of 50 knee experts. It is important to stress that what we present is opinion. This opinion, however, is based on principles, guidelines, and specifics which we be lieve are important. The early phases of our program are based upon time and control of forces, both of which are neces sary for ligament healing. The classic parameters of return to play do not indicate healing of ligament tissue and must not be substituted for time restraints. After ACL repair and reconstruction, there are five phases of rehabilitation: maximum protection (12 weeks), moderate protection (24 weeks), minimum protection (48 weeks), return to activity (60 weeks), and activity and maintenance. The maximum protection phase consists of the early healing period and controlled motion period. The early healing period is governed by a principle which re quires the absolute control of forces to prevent dis ruption of the suture line or attachment site. This time will vary according to the surgical technique. We do not allow motion during this period. During the con trolled motion period, we allow motion but control external forces to protect ligament healing. The moderate protection phase consists of the crutch-weaning and walking periods. The major goal of the moderate protection phase is to prepare the patient for walking. The principles which govern Phase 2 are that walking activities create large anterior cru ciate ligament forces and healing strength is still low. A balance of quadriceps and hamstring forces is nec essary for proper knee kinematics. De-emphasis of quadriceps exercises and emphasis of hamstring mus cles is appropriate; however, both muscle groups must be strengthened. The crutch-weaning period is designed to allow the gradual increase of motion and strength to sustain walking activities. A paradox of exercise exists for strength building. To push weight from 30° of flexion into full extension will protect the patellofemoral joint but will create large forces on the ACL. Our compromise is to push low weight through a full range of motion. We begin full weightbearing no sooner than the 16th week. The final three phases of our program are designed to develop dynamic stability through strength, coor dination, and endurance. Phase 3, the maximum pro tection phase, consists of the protected activity period from the 24th through the 36th week, and the light activity period from the 37th through the 48th week. Restrictions include no running, no jumping, and the use of a brace full-time. The light activity period allows further time to protect the slow healer. This may be shortened or lengthened, depending upon the pa tients condition and goals. Phase 4, the return to activity phase, begins 9 to 12 months after surgery. It consists of the advanced rehabilitation period and the running period. The ad vanced rehabilitation period is designed to achieve maximum strength and further enhance neuromuscu lar coordination and endurance. The running period begins when the operated leg has at least 75% of the strength and power of the normal leg. The activity and maintenance phase consists of the return to sport and maintenance periods. On return to sport, the patient must gradually resume full activity by advancing from skill drills. The maintenance pro gram consists of triweekly strength-building sessions, brace protection during sporting, and avoidance of high-risk activities.

Intra-articular cruciate reconstruction. I: Perspectives on graft strength, vascularization, and immediate motion after replacement.

All of the factors discussed here hopefully will increase the success rate of future intra-articular grafts. But it should not be supposed that the ideal ACL substitution answer is immediately forthcoming. Past experience points to the inherent difficulty of any potential solution and the need to progress in a rigorous scientific manner in the evaluation of the next wave of ligament substitutes. This article reports the utilization of an immediate protective motion program to avoid the problems of postoperative stiffness and lack of knee extension. It can not be stated with certainly whether the same program can be applied to free grafts or to those obtained from other sites. However, the avoidance of these problems will significantly lessen the morbidity of intra-articular reconstruction. The utilization of a vascularized patellar tendon hopefully will add another dimension to ACL replacement.

Shoulder Muscle Activity and Function in Common Shoulder Rehabilitation Exercises

The rotator cuff performs multiple functions during shoulder exercises, including glenohumeral abduction, external rotation (ER) and internal rotation (IR). The rotator cuff also stabilizes the glenohumeral joint and controls humeral head translations. The infraspinatus and subscapularis have significant roles in scapular plane abduction (scaption), generating forces that are two to three times greater than supraspinatus force. However, the supraspinatus still remains a more effective shoulder abductor because of its more effective moment arm.Both the deltoids and rotator cuff provide significant abduction torque, with an estimated contribution up to 35–65% by the middle deltoid, 30% by the subscapularis, 25% by the supraspinatus, 10% by the infraspinatus and 2% by the anterior deltoid. During abduction, middle deltoid force has been estimated to be 434 N, followed by 323N from the anterior deltoid, 283N from the subscapularis, 205N from the infraspinatus, and 117N from the supraspinatus. These forces are generated not only to abduct the shoulder but also to stabilize the joint and neutralize the antagonistic effects of undesirable actions. Relatively high force from the rotator cuff not only helps abduct the shoulder but also neutralizes the superior directed force generated by the deltoids at lower abduction angles. Even though anterior deltoid force is relatively high, its ability to abduct the shoulder is low due to a very small moment arm, especially at low abduction angles. The deltoids are more effective abductors at higher abduction angles while the rotator cuff muscles are more effective abductors at lower abduction angles.During maximum humeral elevation the scapula normally upwardly rotates 45–55°, posterior tilts 20–40° and externally rotates 15–35°. The scapular muscles are important during humeral elevation because they cause these motions, especially the serratus anterior, which contributes to scapular upward rotation, posterior tilt and ER. The serratus anterior also helps stabilize the medial border and inferior angle of the scapular, preventing scapular IR (winging) and anterior tilt. If normal scapular movements are disrupted by abnormal scapular muscle firing patterns, weakness, fatigue, or injury, the shoulder complex functions less efficiency and injury risk increases.Scapula position and humeral rotation can affect injury risk during humeral elevation. Compared with scapular protraction, scapular retraction has been shown to both increase subacromial space width and enhance supraspinatus force production during humeral elevation. Moreover, scapular IR and scapular anterior tilt, both of which decrease subacromial space width and increase impingement risk, are greater when performing scaption with IR (‘empty can’) compared with scaption with ER (‘full can’).There are several exercises in the literature that exhibit high to very high activity from the rotator cuff, deltoids and scapular muscles, such as prone horizontal abduction at 100° abduction with ER, flexion and abduction with ER, ‘full can’ and ‘empty can’, D1 and D2 diagonal pattern flexion and e The serratus anterior also helps stabilize the medial border and inferior angle of the scapular, preventing scapular IR (winging) and anterior tilt. If normal scapular movements are disrupted by abnormal scapular muscle firing patterns, weakness, fatigue, or injury, the shoulder complex functions less efficiency and injury risk increases.Scapula position and humeral rotation can affect injury risk during humeral elevation. Compared with scapular protraction, scapular retraction has been shown to both increase subacromial space width and enhance supraspinatus force production during humeral elevation. Moreover, scapular IR and scapular anterior tilt, both of which decrease subacromial space width and increase impingement risk, are greater when performing scaption with IR (‘empty can’) compared with scaption with ER (‘full can’).There are several exercises in the literature that exhibit high to very high activity from the rotator cuff, deltoids and scapular muscles, such as prone horizontal abduction at 100° abduction with ER, flexion and abduction with ER, ‘full can’ and ‘empty can’, D1 and D2 diagonal pattern flexion and extension, ER and IR at 0° and 90° abduction, standing extension from 90–0°, a variety of weight-bearing upper extremity exercises, such as the push-up, standing scapular dynamic hug, forward scapular punch, and rowing type exercises. Supraspinatus activity is similar between ‘empty can’ and ‘full can’ exercises, although the ‘full can’ results in less risk of subacromial impingement. Infraspinatus and subscapularis activity have generally been reported to be higher in the ‘full can’ compared with the ‘empty can’, while posterior deltoid activity has been reported to be higher in the ‘empty can’ than the ‘full can’.

Core Muscle Activation During Swiss Ball and Traditional Abdominal Exercises

STUDY DESIGN Controlled laboratory study using a repeated-measures, counterbalanced design. OBJECTIVES To test the ability of 8 Swiss ball exercises (roll-out, pike, knee-up, skier, hip extension right, hip extension left, decline push-up, and sitting march right) and 2 traditional abdominal exercises (crunch and bent-knee sit-up) on activating core (lumbopelvic hip complex) musculature. BACKGROUND Numerous Swiss ball abdominal exercises are employed for core muscle strengthening during training and rehabilitation, but there are minimal data to substantiate the ability of these exercises to recruit core muscles. It is also unknown how core muscle recruitment in many of these Swiss ball exercises compares to core muscle recruitment in traditional abdominal exercises such as the crunch and bent-knee sit-up. METHODS A convenience sample of 18 subjects performed 5 repetitions for each exercise. Electromyographic (EMG) data were recorded on the right side for upper and lower rectus abdominis, external and internal oblique, latissimus dorsi, lumbar paraspinals, and rectus femoris, and then normalized using maximum voluntary isometric contractions (MVICs). RESULTS EMG signals during the roll-out and pike exercises for the upper rectus abdominis (63% and 46% MVIC, respectively), lower rectus abdominis (53% and 55% MVIC, respectively), external oblique (46% and 84% MVIC, respectively), and internal oblique (46% and 56% MVIC, respectively) were significantly greater compared to most other exercises, where EMG signals ranged between 7% to 53% MVIC for the upper rectus abdominis, 7% to 44% MVIC for the lower rectus abdominis, 14% to 73% MVIC for the external oblique, and 16% to 47% MVIC for the internal oblique. The lowest EMG signals were consistently found in the sitting march right exercise. Latissimus dorsi EMG signals were greatest in the pike, knee-up, skier, hip extension right and left, and decline push-up (17%-25% MVIC), and least with the sitting march right, crunch, and bent-knee sit-up exercises (7%-8% MVIC). Rectus femoris EMG signal was greatest with the hip extension left exercise (35% MVIC), and least with the crunch, roll-out, hip extension right, and decline push-up exercises (6%-10% MVIC). Lumbar paraspinal EMG signal was relative low (less than 10% MVIC) for all exercises. CONCLUSIONS The roll-out and pike were the most effective exercises in activating upper and lower rectus abdominis, external and internal obliques, and latissimus dorsi muscles, while minimizing lumbar paraspinals and rectus femoris activity. J Orthop Sports Phys Ther 2010;40(5):265-276, Epub 22 April 2010. doi:10.2519/jospt.2010.3073.

Intra-articular cruciate reconstruction. II: Replacement with vascularized patellar tendon.

The patellar tendon offers a number of advantages (strength, location, bone-to-bone fixation, vascularity) as a tissue for intra-articular cruciate ligament reconstruction. The critical factor is to preserve the vascularity, thereby maintaining tendon viability and facilitating tissue remodeling. Laboratory studies on human cadaver knees were conducted to define the blood supply to the patella, and vascularity was assessed by blood flow studies in three animal species, including nonhuman primates. In humans, the patellar ligament receives blood anteriorly from the retinaculum and posteriorly from the fat pad, which is relatively smaller and less adherent than the fat pad in other animals. The medial third of the patellar tendon and its contiguous neurovascular pedicle were used in a vascularized patellar tendon reconstruction procedure. During a period of three years, reconstruction with the vascularized patellar tendon was performed in more than 100 patients. Although only 35 patients have been followed up for more than two years, the clinical results are encouraging. At present, however, the technique is not recommended for general use; the surgical procedure is demanding, and the ultimate clinical results may not warrant the extra effort required to perform the surgery as well as commit the patient to a long rehabilitation program.

Comparison of Three Baseball-Specific 6-Week Training Programs on Throwing Velocity in High School Baseball Players

Abstract Escamilla, RF, Ionno, M, deMahy, MS, Fleisig, GS, Wilk, KE, Yamashiro, K, Mikla, T, Paulos, L, and Andrews, JR. Comparison of three baseball-specific 6-week training programs on throwing velocity in high school baseball players. J Strength Cond Res 26(7): 1767–1781, 2012. Throwing velocity is an important baseball performance variable for baseball pitchers, because greater throwing velocity results in less time for hitters to make a decision to swing. Throwing velocity is also an important baseball performance variable for position players, because greater throwing velocity results in decreased time for a runner to advance to the next base. This study compared the effects of 3 baseball-specific 6-week training programs on maximum throwing velocity. Sixty-eight high school baseball players 14–17 years of age were randomly and equally divided into 3 training groups and a nontraining control group. The 3 training groups were the Throwers Ten (TT), Keiser Pneumatic (KP), and Plyometric (PLY). Each training group trained 3 d·wk−1 for 6 weeks, which comprised approximately 5–10 minutes for warm-up, 45 minutes of resistance training, and 5–10 for cool-down. Throwing velocity was assessed before (pretest) and just after (posttest) the 6-week training program for all the subjects. A 2-factor repeated measures analysis of variance with post hoc paired t-tests was used to assess throwing velocity differences (p < 0.05). Compared with pretest throwing velocity values, posttest throwing velocity values were significantly greater in the TT group (1.7% increase), the KP group (1.2% increase), and the PLY group (2.0% increase) but not significantly different in the control group. These results demonstrate that all 3 training programs were effective in increasing throwing velocity in high school baseball players, but the results of this study did not demonstrate that 1 resistance training program was more effective than another resistance training program in increasing throwing velocity.

Cruciate ligament forces between short-step and long-step forward lunge.

PURPOSE The purpose of this study was to compare cruciate ligament forces between the forward lunge with a short step (forward lunge short) and the forward lunge with a long step (forward lunge long). METHODS Eighteen subjects used their 12-repetition maximum weight while performing the forward lunge short and long with and without a stride. EMG, force, and kinematic variables were input into a biomechanical model using optimization, and cruciate ligament forces were calculated as a function of knee angle. A two-factor repeated-measure ANOVA was used with a Bonferroni adjustment (P < 0.0025) to assess differences in cruciate forces between lunging techniques. RESULTS Mean posterior cruciate ligament (PCL) forces (69-765 N range) were significantly greater (P < 0.001) in the forward lunge long compared with the forward lunge short between 0 degrees and 80 degrees knee flexion angles. Mean PCL forces (86-691 N range) were significantly greater (P < 0.001) without a stride compared with those with a stride between 0 degrees and 20 degrees knee flexion angles. Mean anterior cruciate ligament (ACL) forces were generated (0-50 N range between 0 degrees and 10 degrees knee flexion angles) only in the forward lunge short with stride. CONCLUSIONS All lunge variations appear appropriate and safe during ACL rehabilitation because of minimal ACL loading. ACL loading occurred only in the forward lunge short with stride. Clinicians should be cautious in prescribing forward lunge exercises during early phases of PCL rehabilitation, especially at higher knee flexion angles and during the forward lunge long, which generated the highest PCL forces. Understanding how varying lunging techniques affect cruciate ligament loading may help clinicians prescribe lunging exercises in a safe manner during ACL and PCL rehabilitation.

Effects of a 4-Week Youth Baseball Conditioning Program on Throwing Velocity

Escamilla, RF, Fleisig, GS, Yamashiro, K, Mikla, T, Dunning, R, Paulos, L, and Andrews, JR. Effects of a 4-week youth baseball conditioning program on throwing velocity. J Strength Cond Res 24(12): 3247-3254, 2010-Effects of a 4-week youth baseball conditioning program on throwing velocity. This study examined the effects of a 4-week youth baseball conditioning program on maximum throwing velocity. Thirty-four youth baseball players (11-15 years of age) were randomly and equally divided into control and training groups. The training group performed 3 sessions (each 75 minutes) weekly for 4 weeks, which comprised a sport specific warm-up, resistance training with elastic tubing, a throwing program, and stretching. Throwing velocity was assessed initially and at the end of the 4-week conditioning program for both control and training groups. The level of significance used was p < 0.05. After the 4-week conditioning program, throwing velocity increased significantly (from 25.1 ± 2.8 to 26.1 ± 2.8 m·s−1) in the training group but did not significantly increase in the control group (from 24.2 ± 3.6 to 24.0 ± 3.9 m·s−1). These results demonstrate that the short-term 4-week baseball conditioning program was effective in increasing throwing velocity in youth baseball players. Increased throwing velocity may be helpful for pitchers (less time for hitters to swing) and position players (decreased time for a runner to advance to the next base).

Cruciate ligament tensile forces during the forward and side lunge

BACKGROUND Although weight bearing lunge exercises are frequently employed during anterior cruciate ligament and posterior cruciate ligament rehabilitation, cruciate ligament tensile forces are currently unknown while performing forward and side lunge exercises with and without a stride. METHODS Eighteen subjects used their 12 repetition maximum weight while performing a forward lunge and side lunge with and without a stride. A motion analysis system and biomechanical model were used to estimate cruciate ligament forces during lunging as a function of 0-90 degrees knee angles. FINDINGS Comparing the forward lunge to the side lunge across stride variations, mean posterior cruciate ligament forces ranged between 205 and 765N and were significantly greater (P<0.0025) in the forward lunge long at 40 degrees , 50 degrees , 60 degrees , 70 degrees , and 80 degrees knee angles of the descent phase and at 80 degrees , 70 degrees , 60 degrees knee angles of the ascent phase. There were no significant differences (P<0.0025) in mean posterior cruciate ligament forces between with and without stride differences across lunging variations. There were no anterior cruciate ligament forces quantified while performing forward and side lunge exercises. INTERPRETATION Clinicians should be cautious in prescribing forward and side lunge exercises during early phases of posterior cruciate ligament rehabilitation due to relatively high posterior cruciate ligament forces that are generated, especially during the forward lunge at knee angles between 40 degrees and 90 degrees knee angles. Both the forward and side lunges appear appropriate during all phases of anterior cruciate ligament rehabilitation. Understanding how forward and side lunging affect cruciate ligament loading over varying knee angles may help clinicians better prescribe lunging exercises in a safe manner during anterior cruciate ligament and posterior cruciate ligament rehabilitation.

Cruciate ligament loading during common knee rehabilitation exercises

Cruciate ligament injuries are common and may lead to dysfunction if not rehabilitated. Understanding how to progress anterior cruciate ligament and posterior cruciate ligament loading, early after injury or reconstruction, helps clinicians prescribe rehabilitation exercises in a safe manner to enhance recovery. Commonly prescribed therapeutic exercises include both weight-bearing exercise and non-weight-bearing exercise. This review was written to summarize and provide an update on the available literature on cruciate ligament loading during commonly used therapeutic exercises. In general, weight-bearing exercise produces smaller loads on the anterior cruciate ligament and posterior cruciate ligament compared with non-weight-bearing exercise. The anterior cruciate ligament is loaded less at higher knee angles (i.e. 50–100°). Squatting and lunging with a more forward trunk tilt and moving the resistance pad proximally on the leg during the seated knee extension unloads the anterior cruciate ligament. The posterior cruciate ligament is less loaded at lower knee angles (i.e. 0–50°), and may be progressed from level ground walking to a one-leg squat, lunges, wall squat, leg press, and the two-leg squat (from smallest to greatest). Exercise type and technique variation affect cruciate ligament loading, such that the clinician may prescribe therapeutic exercises to progress ligament loading safely, while ensuring optimal recovery of the musculoskeletal system.