Apr 7, 2016Thrown For A Curve
Inconsistent approaches to diagnosis, treatment, and recovery have left many athletic trainers wondering how to best address injuries to the glenoid labrum. The Shoulder Center of Kentucky has had success by utilizing the latest research and a comprehensive clinical approach.
This article first appeared in the April 2016 issue of Training and Conditioning.
Not long ago, a labral injury was viewed as a career-ender for most athletes-especially those in overhead sports. In fact, a 2004 survey found only three percent of MLB pitchers returned to the same level of play following a labral tear. While recent outcomes aren’t as dire-a 2012 survey put the return-to-play rate for MLB pitchers at 14 percent-there’s still a lot of room for improvement.
The biggest roadblock is the contradictory nature of labral injuries. For instance, many athletes have symptoms following a labral tear, but some don’t. To diagnose the injury, numerous clinicians rely on a physical exam, imaging, or arthroscopic evaluation, while others use all three. And even treatment recommendations can vary between conservative rehab and surgical repair.
These conflicts suggest that we are still limited in our knowledge of how to best evaluate and address lesions to the glenoid labrum. However, that doesn’t mean success is unattainable. By providing a review of the literature and sharing how we’ve attained positive results at the Shoulder Center of Kentucky, I aim to clarify the function of the labrum and explain how to manage labral injuries in a clinical setting.
A better understanding of the labrum itself can lead to a better understanding of how to diagnose and treat labral injuries. Current literature has clarified the importance of the superior labrum in the shoulder complex by detailing its many functions.
Traditionally, it was thought the labrum’s roles were threefold: serving as an attachment site for the biceps, deepening the glenohumeral socket and minimizing glenohumeral translation as a bumper, and increasing capsular tension. Recent biomechanical studies, however, have highlighted three additional functions:
• Serving as a deformable structure between two surfaces to more evenly distribute contact pressures, increase boundary lubrication, and maximize concavity/compression characteristics-much like a washer between a nut and bolt
• Acting as a pressure sensor to maximize proprioceptive feedback
• Serving as an attachment site for muscles and ligaments to optimize their tension.
Combined, all six roles allow the labrum to control functional glenohumeral stability at high speeds of rotation, extreme changes in bony positions, and high applied loads. When things are running smoothly, the shoulder has an effortless rotation, stable ball and socket kinematics, and maximal force transfer from the core and legs to the hand.
Yet, athletic trainers know things don’t always run smoothly, and injuries will happen. In 1990, Stephen Snyder, MD, one of the founding partners of the Southern California Orthopedic Institute, developed the now widely adopted classification system to describe the four types of superior labral lesions. They are:
Type I: Fraying of the superior labrum
Type II: Detachment of the superior labrum from the glenoid
Type III: Bucket-handle tear of the superior labrum
Type IV: Detachment of the superior labrum from the glenoid, along with injury into the long head of the biceps tendon.
Labral lesions are caused by one of three factors: degeneration over time, acute trauma, or overuse. Acute labral injuries generally result from a directional shear between the humeral head and glenoid. When the humeral head is compressed against the glenoid fossa and forcefully translated against the tissue beyond its natural limit, the labrum sustains a lesion. This is commonly seen in shoulder dislocations or when an athlete falls on their outstretched arm.
Overuse superior labral injuries appear in overhead athletes as a result of repetitive arm motions. These injuries occur for one of two reasons-either the body is not being physiologically optimized, meaning it lacks the strength, muscle endurance, flexibility, and balance needed to withstand the repetitive stresses of overhead arm motions, or the body is not biomechanically optimized because the athlete has poor mechanics. In either scenario, the position of the arm in relation to the scapula becomes altered at some point. Repetitive throwing causes the long head of the biceps to tension the labrum beyond its anatomical limit, straining the biceps/labrum complex and leading to a labral lesion.
TOUGH TO DIAGNOSE
Some medical professionals suggest that superior labral lesions are over-diagnosed, pointing to past reports where any and all visualized variants in the glenoid labrum were surgically treated. This trend is concerning because “abnormal” labral findings do not always coincide with clinical symptoms or an athlete’s inability to perform sport-specific tasks. There have been incidents where surgical repair of benign abnormalities did not improve patients’ symptoms and even worsened their functional loss.
Recent evidence suggests the over-diagnosis of labral injuries could stem from limitations within the existing literature. A 2015 systematic review published in Arthroscopy found that the methods used to identify these lesions were varied and inconsistent. This lack of consensus may be hindering clinicians’ ability to establish whether a clinically significant labral injury is present. As a result, labral injury becomes the catchall diagnosis for any athlete experiencing shoulder pain of unknown origin.
The key to reversing this trend is getting away from using pain as an indication of labral injury. While pain serves as a signal that something may be wrong in the shoulder joint, a clinically significant injury involves much more. It occurs when an anatomic alteration in the labrum results in shoulder dysfunction that can be attributed to loss of labral roles and highlighted in specific physical exams.
Patient complaints suggestive of loss of labral roles include:
• Pain upon external rotation/cocking, which indicates increased posterior superior translation
• Weakness in clinical or functional arm strength, which indicates pain and/or increased translation
• Symptoms of internal derangement, such as clicking, popping, catching, or sliding, which indicate the loss of the bumper effect or washer effect
• Decreased capsular tension and a feeling of a “dead arm,” which indicates the loss of proprioceptive feedback, decreased capsular tension, and increased translation.
Once loss of labral roles has been established, a three-step approach is recommended to diagnose a labral injury: 1) Clinical impression incorporating both patient complaints and physical exam maneuvers; 2) Assistance via advanced imaging; and 3) Surgical exploration (but only sometimes).
While attempts have been made to refine the physical exam, existing tests often fall short of consistently identifying labral lesions. There are multiple reasons for this, including clinicians’ lack of familiarity with the techniques, low-quality research supporting the maneuvers, and labral lesions having multiple iterations that prevent the exam from detecting the various types (i.e., some maneuvers may excel at uncovering superior labral lesions while others may only pinpoint posterior lesions). Although a standard battery of tests has yet to be determined, the best available evidence supports using modified dynamic labral shear, passive compression, passive distraction, and active compression tests.
The modified dynamic labral shear test has been shown to have high clinical utility. A positive test indicates a loss of biceps stability, loss of washer effect, and increased translation.
Starting with the arm at the side of the body, the passive compression test creates tension in the long head of the biceps tendon by externally rotating the arm while in slight abduction. This is followed by applying pressure on the labrum via passive superior translation of the humeral head on the glenoid. Combined, these actions compress and distract the injured superior labrum, causing pain.
The passive distraction test requires placing the arm in 150 degrees of abduction with the forearm supinated. Passive movement of the forearm into pronation tensions the biceps, creating distraction of the superior labrum away from the glenoid.
The active compression test is performed with the arm at 90 degrees of elevation and the elbow extended. The arm is then internally rotated along the long axis, which applies tension to the biceps/labral complex, and the patient is asked to manually resist a downward force from the examiner. These actions cause pain in an injured superior labrum due to the lack of soft-tissue attachment to the glenoid. A positive passive compression, passive distraction, or active compression test indicates a loss of the washer effect, increased biceps tension, and increased translation.
At the Shoulder Center of Kentucky, we have added a few more maneuvers to our clinical exam. We have found several specific intra-articular tests can assist in providing clues to loss of labral roles. For example, a positive painful arc of motion test (pain between 130 and 60 degrees of abduction) in the Hawkins-type motion, with no relief from scapular posterior tilt in the scapula assistance test (manual assistance applied to the scapula during arm elevation) indicates increased translation. Additionally, a positive lift-off maneuver (traditionally reserved for subscapularis rotator cuff muscle injury detection) can hint at a loss of the labrum’s role as a tension band.
Clinicians should note that examination tests are only useful when they are familiar with the application of the maneuvers and know how to interpret the findings. Even with sound scientific evidence supporting its use, a test is unlikely to be helpful if the person administering it doesn’t understand the intricacies of the technique.
Evidence has shown that a large number of labral variants can be identified with advanced imaging. However, these variants were found in patients with and without symptoms. This suggests that imaging should supplement the findings of clinical exam maneuvers and patient complaints regarding loss of function-not serve as the sole diagnostic tool. Some of the imaging types we use include MRI, MRI arthrography, or CT arthrogram.
If a superior labral injury is suspected, our standard of practice has been to initially attempt conservative treatment for six to 10 weeks. If this rehabilitation fails to reduce symptoms or restore function, advanced imaging is employed. We only pursue surgical exploration when we have established that rehabilitation is not helping and imaging has identified a defect.
Following proper clinical diagnosis of a labral injury, it remains until surgically repaired. Self-healing rarely, if ever, occurs. However, studies indicate that around half of all lesions can be symptomatically resolved through rehabilitation, allowing athletes to return to play without undergoing surgery. Therefore, conservative treatment should always be attempted first.
A rehab program for labral injury should be designed to improve the physiological capability of the musculoskeletal system around the shoulder, which will reduce the deficits that may be causing symptoms. Our approach focuses on each segment within the kinetic chain, including the lower extremity, trunk/core, and upper extremity. In addition, our rehab program contains six goals:
• Establish proper postural alignment
• Establish proper motion at all involved segments
• Facilitate scapular motion via exaggeration of lower extremity/trunk movement
• Exaggerate scapular retraction in controlling excessive protraction
• Utilize closed-chain exercises early
• Work in multiple planes.
When starting a labrum rehab, select exercises based on the individual. For example, some athletes have proper postural alignment even in the presence of injury. In those cases, we would pay little attention to postural exercises during their rehab.
In general, we rarely have patients perform exercises in prone or supine positions because these are counterintuitive to kinetic chain function. Overhead athletes in particular require trunk and leg muscle activation for stabilization and power generation, so their exercises should always be performed while standing.
Utilizing the larger kinetic chain segments within the first three weeks of rehabilitation begins retraining the motor system to generate appropriate muscle activation patterns. This can be accomplished in exercises such as the low row and robbery, which facilitate scapular retraction through leg and trunk extension. Once patients demonstrate mastery of these maneuvers, they should advance to performing them while simultaneously challenging their legs and trunk via an aerobic step or other stable platform.
Once the clinician feels motor control between the legs and arm is adequate and the scapula is stabilized, traditional rotator cuff exercises can be performed from a standing position. We recommend a high-repetition, low-resistance program for overhead athletes, since they will focus on rebuilding strength during their return-to-play progression.
Surgical treatment should be reserved for patients who have overt instability or a lack of response to conservative treatment. Arthroscopy of the labrum is the recommended procedure, but the arthroscopic fixation must be specific. A recent systematic review revealed that there is wide variability in the reported arthroscopic indications for repair and the specific technical details to accomplish it-so no standard best practice exists. These knowledge gaps make it difficult to critically compare outcomes within the literature, which can lead to a gap in treatment.
That being said, the arthroscopic findings that most frequently result in a loss of labral function, and are therefore surgically repaired, include:
• A Type II or higher lesion denoting loss of attachment
• A peel-back phenomenon indicating increased compliance, loss of washer effect, and loss of bumper effect
• Glenoid articular cartilage damage or chondromalacia, indicating increased translation
• Loss of capsular tension indicated by loss of tension in the posterior band of the inferior glenohumeral ligament
• Excessive posterior-inferior capsular thickness and scarring, indicating end stage capsular damage.
RETURN TO PLAY
After receiving treatment for a labral injury, the first question athletes ask is: “When can I play again?” Unfortunately, return to pre-injury levels of activity is not always attainable and hard to predict. Although a 2015 review published in the Journal of Athletic Training found that the odds of returning to play in full were two to six times greater for non-overhead athletes, overall rates following both surgical and non-surgical treatments were inconsistent.
To maximize the chances of getting overhead athletes back in the game following superior labral injury, we use a return-to-play protocol focused on building muscle endurance and proprioception. Once kinetic chain deficits have been corrected in formal rehabilitation, we target lower-extremity muscle power and endurance, integrated sports-specific exercise, and upper-extremity power and endurance. These areas are important for overhead athletes because force is developed in the legs and trunk and then funneled through the scapulohumeral complex before being transferred to the arm.
High-repetition exercises designed to increase lower-extremity muscle endurance are employed first. We focus on the major muscle groups, such as the gastrocnemius/soleus, quadriceps, hamstrings, and hip abductors.
Integrated sports-specific activities are then employed to use the improved lower-extremity muscle strength and help facilitate upper-extremity muscle activation. Synchronous single-leg and transverse plane exercises are crucial at this stage to aid in improving proprioception as well as muscle education.
Finally, we address upper-extremity power and endurance via high-repetition, long-lever exercises (with the elbow extended and away from the body) performed in standing and prone positions. Athletes typically spend 24 weeks or longer in this return-to-play program after a surgical repair.
It should be noted that in our clinical experience, overhead athletes who experience improvements in lower-extremity or core strength through our return-to-plan protocol occasionally have difficulty when they start throwing again. They often need two to four weeks to learn how to appropriately utilize the gains. We aid them in this endeavor with a return-to-throwing program that gradually increases their number of throws and distance over multiple weeks.
An exact time frame to get back to full activity following labral injury does not exist. A range of six to 12 months is often reported. However, overhead athletes can take as long as 18 months.
Although the rates aren’t as high as many would like, successful return to play is possible for athletes who sustain a labral injury. Until more is learned about this perplexing malady, the best approach for proper identification and treatment is an integrated one-utilizing patient history, clinical experience, and current literature.
To view a list of references for this article, go to: Training-Conditioning.com/References.
Last year, an elite, junior level 17-year-old female tennis player reported to the Shoulder Center of Kentucky for evaluation of shoulder pain in her dominant arm. The athlete’s history revealed she underwent arthroscopic debridement of that same arm six months prior by a separate physician, which had relieved some of her symptoms and enabled her to return to play. However, her soreness and functional loss eventually returned. Not long after the pain came back, she found there was a limit to the number of hours or days in a row she could play before experiencing symptoms.
At her initial visit, the tennis player reported pain and soreness while doing overhead activities, such as serving and hitting high forehands. In addition, she was experiencing aches and pain deep in the joint, with decreased strength and an inability to complete normal activities.
During the physical exam, the athlete displayed weakness in both hips, especially the left, with good spinal flexibility. She had some weakness in scapular retraction, no scapular dyskinesis with forward flexion, and adequate rotator cuff strength off of a stabilized scapula.
Clinical exam maneuvers revealed positive modified dynamic labral shear, active compression, and lift-off tests, indicating loss of the tension band component of the labrum. She had no signs of joint instability, and her imaging revealed a superior and posterior labral injury.
Our first step for treatment was to put the athlete through a rehabilitation plan. She was still following her post-op therapy program when she came to the Shoulder Center, and it concentrated on power exercises like squats, lunges, and cleans, as well as scapular work with long-lever exercises. We modified this program to focus on endurance. Tubing replaced the weights, and the lever arm was reduced by using movements that required a flexed elbow, such as rows.
We held the athlete out of hitting and playing for three weeks, and she began our modified rehab plan. However, the dysfunction had not changed six weeks later, so surgery was the next step.
Repairing the labral injury required inserting three anchors (one posteriorly and two superiorly) to achieve stabilization. Following surgery, the athlete entered post-operative rehabilitation. She performed a number of standing passive- and active-assisted range-of-motion and kinetic chain-based exercises to improve scapular retraction and depression.
After scapular control was achieved and motion progressed six weeks later, short-lever rotator cuff-focused exercises were implemented. These progressed to long-lever maneuvers over a period of eight weeks. Sets and reps were steadily increased, while primarily using elastic bands for resistance. Next, upper-body plyometric exercises were implemented for four weeks.
Finally, five months after coming to our clinic, the athlete began a tennis-specific return-to-play protocol. The program incorporates three phases (preparatory, strength and endurance, and power and endurance) that progressively transition the athlete into increased stroke volume and intensity without overloading the shoulder. It is based on the principles that each player hits approximately 120 serves and 210 groundstrokes per match.
The athlete began with 30 minutes of groundstrokes three times per week for one month. She then introduced the service motion, starting with two serves per day and adding two additional serves every other day until she reached 40 serves per day.
The final step was progressing to full 90- to 120-minute tennis practices twice a day, five days a week. The athlete continues to perform maintenance rehabilitation, and she is set to return for her first post-injury tournament this spring.