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An Analysis of Glenohumeral Elevation Using 3D Computed Tomography (3D Ct) in Patients with Shoulder Instability
2013 ISAKOS ABSTRACTS
and 3.) for a type III tear after transection of the root and the meniscofemoral ligament. To calculate the mean intraarticular pressure a region of interest (ROI) was used. The ROI was defined as the 1.0 1.0 cm2 area around the peak contact pressure. Statistical analysis was performed by the use of SPSS Software for Windows, release 15.0.1 (SPSS, Chicago, IL). Before statistical testing, each continuous variable was analyzed in an explorative manner for its normal distribution (Kolmogorov-Smirnov test). The Mann-Whitney U test was used for comparison of nonparametric variables (peak contact pressure, difference in pressure) between each study group. The significance level was P < .05. Results: In case of an intact posterior attachment of the lateral meniscus the axial load of 100 N creates an intraarticular pressure of 120 kPa. After creation of a posterior type I root tear (transection of the root) no significant increase of intraarticular pressure was measured (141 kPa; p<0,6). The type III root tear (transection of the root and the MFL) leads to a significant increase of the intraarticular pressure up to 946 kPa (p<0,004). Discussion: The isolated root tear (type I) has no significant influence on the intraarticular pressure. The MFL holds the meniscus in place and restores the lateral meniscus function guaranteeing an equal distribution of the intraarticular joint pressure. The type III tear leads to an extrusion of the lateral meniscus and a decrease of the contact area with a significant increase of the intraarticular pressure. These results support the usefulness of a root tear classification of the posterior lateral meniscus. The classification of lateral meniscus root tears allows estimation of the impact of different tear localizations. In clinical practice we recommend a fixation of a root tear in case of an MFL injury or absence of the MFL. Paper #190: Tibiofemoral Contact Mechanics Following Posterior Root of Medial Meniscus Tear, Repair, Meniscectomy and Allograft Transplantation YONG SEUK LEE, MD, PHD, KOREA PRESENTING AUTHOR JIN GOO KIM, MD, PHD, KOREA JEONG KU HA, MD, KOREA HO JONG RA, MD, KOREA $ Paik (Inje) and Gil (Gachon) Hospital, Seoul and Incheon, Korea
SUMMARY Both meniscal root repair and transplantation of meniscus improved contact mechanics, but it did not appear that repair of the meniscal root or transplantation of meniscus restores the biomechanical function back to normal level. ABSTRACT DATA Purpose: The Purposes of this study were to evaluate the effect on tibiofemoral contact mechanics of repair of the posterior root of the medial meniscus and the effect of meniscal allograft transplantation with medial collateral ligament release at different flexion angles. Methods: Ten fresh-frozen human cadaveric knees (five pairs) were used. A digital pressure sensor was inserted by capsulotomy and experiments were performed serially under the following six conditions, that is, with an intact medial meniscus (normal controls), with a root tear, after
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root repair, after total meniscectomy, after meniscal allograft transplantation, and after meniscal allograft transplantation plus medial collateral ligament release. During each experiment, knees were positioned at 0 , 30 , 60 , and 90 of flexion and peak pressure (kPa) and contact area (cm2) were measured. Results: At 0 of flexion, contact pressure did not differ among the six experimental settings. However, at 30 and 60 of flexion, contact pressure differed significantly between root tear and root repair specimens (p ¼ 0.04 and 0.03, respectively) and between total meniscectomy and meniscal allograft transplantation specimens (p ¼ 0.02 and 0.03, respectively). On the other hand, mean contact pressures were different between normal (476.7473.1 and 573.3479.1 kPa) and root repair (575.7357.8 and 598.6415.8) and between normal and meniscal allograft transplantation (635.7437.4 and 674.3533.2). At 0 , 30 , 60 , and 90 of flexion, contact areas differed significantly between normal and total meniscectomy specimens (p ¼ 0.02, 0.01, 0.02, and 0.02, respectively) and between meniscal allograft transplantation and total meniscectomy specimens (p ¼ 0.03, 0.02, 0.02, and 0.03, respectively). Contact areas differed significantly between root tear and root repair specimens at 60 of flexion (p ¼ 0.04), and between normal control and root repair specimens at 60 and 90 of flexion (p ¼ 0.03 and 0.04, respectively). The effects of meniscal allograft transplantation plus medial collateral ligament release on contact mechanics were not different from the effects of meniscal allograft transplantation alone (n.s.). Conclusions: Both meniscal root repair and transplantation of meniscus improved contact mechanics, but it did not appear that repair of the meniscal root or transplantation of meniscus restores the biomechanical function back to normal level. The meniscal allograft transplantation plus medial collateral ligament release were similar to those after meniscal allograft transplantation alone. Therefore, it is better to preserve meniscus and medial collateral ligament release could be done during the meniscal allograft transplantation. Paper #191: An Analysis of Glenohumeral Elevation Using 3D Computed Tomography (3D Ct) in Patients with Shoulder Instability NEIL BAKSHI, BA, USA PRESENTING AUTHOR OMAR JAMEEL, MBBS, USA ZACH MERRILL, BS, USA RICHARD DEBSKI, USA JON K. SEKIYA, MD, USA $ University of Michigan, Ann Arbor, MI, USA
SUMMARY Surgical intervention for shoulder instability limits the amount of elevation at the glenohumeral junction and may indicate the need to limit the surgical correction of shoulder instability and restore/maintain normal glenohumeral anatomy. ABSTRACT DATA Introduction: The shoulder joint is the most dislocated joint in the body. The incidence of dislocation in the overall population is 4%, with higher rates in athletic and military
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2013 ISAKOS ABSTRACTS
populations. Recurrent instability is a particular problem in the shoulder as recurrence rates have been reported between 20-90%. The pathologic anatomy underlying recurrent shoulder instability includes bony abnormalities of the glenoid and humeral head, impairments and imbalances in muscle function, and ligament tears and laxity. Patients that have been diagnosed with and/or treated for shoulder instability may experience a decrease in their biomechanical range of motion, including limited amounts of elevation (abduction) at the glenohumeral junction. Normal glenohumeral elevation has a maximum of 100-110 degrees, with scapulothoracic elevation being utilized to attain greater levels of abduction. We hypothesize that patients that have experienced shoulder instability will be significantly limited in their maximal levels of glenohumeral elevation compared to normal shoulders. Methods: 39 patients that have experienced shoulder instability were examined in the orthopedic surgery clinic at the University of Michigan. 14 of the 39 patients had failed soft tissue surgical repairs, 10 had successful surgical repairs, and 15 had no previous surgical intervention. All 39 patients had bilateral shoulder CT scans performed in three positions. These positions include 0 degrees of abduction and 0 degrees of external rotation (0-0), 30 degrees of abduction and 30 degrees of external rotation (30-30), and an overhead position at approximately 165 degrees of abduction and 55 degrees of external rotation (OH). Using MIMICS and 3-MATIC, 3D CT reconstruction is performed for both shoulders in all three positions, yielding six total models. A specialized coordinate system is used to mark specific points and directions on the humerus and glenoid of each model. These coordinates are then used to calculate the glenohumeral elevation for the normal and affected sides in the 0-0, 30-30, and OH positions. A paired, 2-tailed t-test was used to determine any significant differences between the affected shoulder and normal, unaffected shoulder of a patient. Results: No differences in glenohumeral elevation were seen in the 0-0 and 30-30 positions when comparing a patient’s affected shoulder to his/her normal side for all three patient groups. In the overhead position, equal amounts of abduction and external rotation were measured bilaterally using the goniometer at the time of CT acquisition for all patients. However, patients with failed surgical intervention had significantly less glenohumeral elevation on the affected side (95.6 degrees) when compared to the normal shoulder (101.5 degrees, p¼ .029). Surgically stabilized shoulders (93.6 degrees) also had significantly less glenohumeral elevation compared to their normal sides (102.1 degrees, p¼.035). However, unstable shoulders with no prior surgical correction (102.1 degrees) did not differ when compared to their contralateral, unaffected sides (101.9 degrees, p¼.95). Discussion: Surgical intervention, regardless of whether it was successful or failed, limits the amount of elevation (abduction) at the glenohumeral junction. As a result, patients that have received surgical intervention may utilize greater levels of scapulothoracic elevation to attain levels of abduction equal to their normal side. This limitation in their biomechanical range of motion indicates that failed and surgically stabilized shoulders will not return
completely back to normal, which may be of great importance to highly active and military populations. Conversely, patients without previous surgical correction do not have any limitations in their glenohumeral elevation The findings regarding surgically stabilized patients corroborate the idea that a surgeon often sacrifices range of motion at the shoulder joint for stability when correcting a case of shoulder instability. Many surgeons will tighten the capsule more than normal and will limit the range of motion to ensure that the humeral head will not incur future dislocation. The findings regarding the failed surgical intervention patients call into question the mentality that failed soft tissue repairs do not impair the function and range of motion at the shoulder joint. Each of our failed patients had a previous soft tissue repair, which significantly decreased their glenohumeral elevation in the overhead position. This indicates that there are significant lasting effects of failed soft tissue repair, suggesting that we must proceed with caution when determining the most appropriate treatment for shoulder instability. These findings also suggest that we should attempt to maintain/restore normal glenohumeral anatomy and implement other forms of treatment such as physical therapy prior to the utilization of surgical correction. In light of these findings, we plan to enroll patients that have received physical therapy for shoulder instability to compare the biomechanical changes associated with its use to that of surgical intervention. The main limitation of this study is a small sample size. However, we will continue to add patients to strengthen our current conclusions and reveal other minor biomechanical changes. Paper #192: Glenoid Morphology after Arthroscopic Osseous Bankart Repair for Recurrent Anterior Glenohumeral Instability: A 5- to 8-Year Follow-up SOUICHIROU KITAYAMA, MD, JAPAN PRESENTING AUTHOR HIROYUKI SUGAYA, MD, JAPAN NORIMASA TAKAHASHI, MD, JAPAN NOBUAKI KAWAI, MD, JAPAN MOTOKI TANAKA, MD, JAPAN MORIHITO TOKAI, MD, JAPAN WATARU IWAMOTO, MD, JAPAN KAZUNORI YASUDA, MD, PHD, JAPAN $ Funabashi Orthopaedic Hospital, Funabashi, Chiba, Japan
SUMMARY Arthroscopic osseous Bankart repair is an effective procedure especially for shoulders with significant bone loss. The Purpose of this study was to assess the clinical results after this procedure over at least 5 years. Arthroscopic osseous Bankart repair can be expected to produce a successful outcome without recurrence once bony union is obtained. Glenoid morphology can be almost normalized. ABSTRACT DATA Introduction: Arthroscopic osseous Bankart repair was introduced almost a decade ago and, although technically demanding in some specific cases, not a few surgeons recognized the effectiveness of this procedure especially for
and 3.) for a type III tear after transection of the root and the meniscofemoral ligament. To calculate the mean intraarticular pressure a region of interest (ROI) was used. The ROI was defined as the 1.0 1.0 cm2 area around the peak contact pressure. Statistical analysis was performed by the use of SPSS Software for Windows, release 15.0.1 (SPSS, Chicago, IL). Before statistical testing, each continuous variable was analyzed in an explorative manner for its normal distribution (Kolmogorov-Smirnov test). The Mann-Whitney U test was used for comparison of nonparametric variables (peak contact pressure, difference in pressure) between each study group. The significance level was P < .05. Results: In case of an intact posterior attachment of the lateral meniscus the axial load of 100 N creates an intraarticular pressure of 120 kPa. After creation of a posterior type I root tear (transection of the root) no significant increase of intraarticular pressure was measured (141 kPa; p<0,6). The type III root tear (transection of the root and the MFL) leads to a significant increase of the intraarticular pressure up to 946 kPa (p<0,004). Discussion: The isolated root tear (type I) has no significant influence on the intraarticular pressure. The MFL holds the meniscus in place and restores the lateral meniscus function guaranteeing an equal distribution of the intraarticular joint pressure. The type III tear leads to an extrusion of the lateral meniscus and a decrease of the contact area with a significant increase of the intraarticular pressure. These results support the usefulness of a root tear classification of the posterior lateral meniscus. The classification of lateral meniscus root tears allows estimation of the impact of different tear localizations. In clinical practice we recommend a fixation of a root tear in case of an MFL injury or absence of the MFL. Paper #190: Tibiofemoral Contact Mechanics Following Posterior Root of Medial Meniscus Tear, Repair, Meniscectomy and Allograft Transplantation YONG SEUK LEE, MD, PHD, KOREA PRESENTING AUTHOR JIN GOO KIM, MD, PHD, KOREA JEONG KU HA, MD, KOREA HO JONG RA, MD, KOREA $ Paik (Inje) and Gil (Gachon) Hospital, Seoul and Incheon, Korea
SUMMARY Both meniscal root repair and transplantation of meniscus improved contact mechanics, but it did not appear that repair of the meniscal root or transplantation of meniscus restores the biomechanical function back to normal level. ABSTRACT DATA Purpose: The Purposes of this study were to evaluate the effect on tibiofemoral contact mechanics of repair of the posterior root of the medial meniscus and the effect of meniscal allograft transplantation with medial collateral ligament release at different flexion angles. Methods: Ten fresh-frozen human cadaveric knees (five pairs) were used. A digital pressure sensor was inserted by capsulotomy and experiments were performed serially under the following six conditions, that is, with an intact medial meniscus (normal controls), with a root tear, after
e149
root repair, after total meniscectomy, after meniscal allograft transplantation, and after meniscal allograft transplantation plus medial collateral ligament release. During each experiment, knees were positioned at 0 , 30 , 60 , and 90 of flexion and peak pressure (kPa) and contact area (cm2) were measured. Results: At 0 of flexion, contact pressure did not differ among the six experimental settings. However, at 30 and 60 of flexion, contact pressure differed significantly between root tear and root repair specimens (p ¼ 0.04 and 0.03, respectively) and between total meniscectomy and meniscal allograft transplantation specimens (p ¼ 0.02 and 0.03, respectively). On the other hand, mean contact pressures were different between normal (476.7473.1 and 573.3479.1 kPa) and root repair (575.7357.8 and 598.6415.8) and between normal and meniscal allograft transplantation (635.7437.4 and 674.3533.2). At 0 , 30 , 60 , and 90 of flexion, contact areas differed significantly between normal and total meniscectomy specimens (p ¼ 0.02, 0.01, 0.02, and 0.02, respectively) and between meniscal allograft transplantation and total meniscectomy specimens (p ¼ 0.03, 0.02, 0.02, and 0.03, respectively). Contact areas differed significantly between root tear and root repair specimens at 60 of flexion (p ¼ 0.04), and between normal control and root repair specimens at 60 and 90 of flexion (p ¼ 0.03 and 0.04, respectively). The effects of meniscal allograft transplantation plus medial collateral ligament release on contact mechanics were not different from the effects of meniscal allograft transplantation alone (n.s.). Conclusions: Both meniscal root repair and transplantation of meniscus improved contact mechanics, but it did not appear that repair of the meniscal root or transplantation of meniscus restores the biomechanical function back to normal level. The meniscal allograft transplantation plus medial collateral ligament release were similar to those after meniscal allograft transplantation alone. Therefore, it is better to preserve meniscus and medial collateral ligament release could be done during the meniscal allograft transplantation. Paper #191: An Analysis of Glenohumeral Elevation Using 3D Computed Tomography (3D Ct) in Patients with Shoulder Instability NEIL BAKSHI, BA, USA PRESENTING AUTHOR OMAR JAMEEL, MBBS, USA ZACH MERRILL, BS, USA RICHARD DEBSKI, USA JON K. SEKIYA, MD, USA $ University of Michigan, Ann Arbor, MI, USA
SUMMARY Surgical intervention for shoulder instability limits the amount of elevation at the glenohumeral junction and may indicate the need to limit the surgical correction of shoulder instability and restore/maintain normal glenohumeral anatomy. ABSTRACT DATA Introduction: The shoulder joint is the most dislocated joint in the body. The incidence of dislocation in the overall population is 4%, with higher rates in athletic and military
e150
2013 ISAKOS ABSTRACTS
populations. Recurrent instability is a particular problem in the shoulder as recurrence rates have been reported between 20-90%. The pathologic anatomy underlying recurrent shoulder instability includes bony abnormalities of the glenoid and humeral head, impairments and imbalances in muscle function, and ligament tears and laxity. Patients that have been diagnosed with and/or treated for shoulder instability may experience a decrease in their biomechanical range of motion, including limited amounts of elevation (abduction) at the glenohumeral junction. Normal glenohumeral elevation has a maximum of 100-110 degrees, with scapulothoracic elevation being utilized to attain greater levels of abduction. We hypothesize that patients that have experienced shoulder instability will be significantly limited in their maximal levels of glenohumeral elevation compared to normal shoulders. Methods: 39 patients that have experienced shoulder instability were examined in the orthopedic surgery clinic at the University of Michigan. 14 of the 39 patients had failed soft tissue surgical repairs, 10 had successful surgical repairs, and 15 had no previous surgical intervention. All 39 patients had bilateral shoulder CT scans performed in three positions. These positions include 0 degrees of abduction and 0 degrees of external rotation (0-0), 30 degrees of abduction and 30 degrees of external rotation (30-30), and an overhead position at approximately 165 degrees of abduction and 55 degrees of external rotation (OH). Using MIMICS and 3-MATIC, 3D CT reconstruction is performed for both shoulders in all three positions, yielding six total models. A specialized coordinate system is used to mark specific points and directions on the humerus and glenoid of each model. These coordinates are then used to calculate the glenohumeral elevation for the normal and affected sides in the 0-0, 30-30, and OH positions. A paired, 2-tailed t-test was used to determine any significant differences between the affected shoulder and normal, unaffected shoulder of a patient. Results: No differences in glenohumeral elevation were seen in the 0-0 and 30-30 positions when comparing a patient’s affected shoulder to his/her normal side for all three patient groups. In the overhead position, equal amounts of abduction and external rotation were measured bilaterally using the goniometer at the time of CT acquisition for all patients. However, patients with failed surgical intervention had significantly less glenohumeral elevation on the affected side (95.6 degrees) when compared to the normal shoulder (101.5 degrees, p¼ .029). Surgically stabilized shoulders (93.6 degrees) also had significantly less glenohumeral elevation compared to their normal sides (102.1 degrees, p¼.035). However, unstable shoulders with no prior surgical correction (102.1 degrees) did not differ when compared to their contralateral, unaffected sides (101.9 degrees, p¼.95). Discussion: Surgical intervention, regardless of whether it was successful or failed, limits the amount of elevation (abduction) at the glenohumeral junction. As a result, patients that have received surgical intervention may utilize greater levels of scapulothoracic elevation to attain levels of abduction equal to their normal side. This limitation in their biomechanical range of motion indicates that failed and surgically stabilized shoulders will not return
completely back to normal, which may be of great importance to highly active and military populations. Conversely, patients without previous surgical correction do not have any limitations in their glenohumeral elevation The findings regarding surgically stabilized patients corroborate the idea that a surgeon often sacrifices range of motion at the shoulder joint for stability when correcting a case of shoulder instability. Many surgeons will tighten the capsule more than normal and will limit the range of motion to ensure that the humeral head will not incur future dislocation. The findings regarding the failed surgical intervention patients call into question the mentality that failed soft tissue repairs do not impair the function and range of motion at the shoulder joint. Each of our failed patients had a previous soft tissue repair, which significantly decreased their glenohumeral elevation in the overhead position. This indicates that there are significant lasting effects of failed soft tissue repair, suggesting that we must proceed with caution when determining the most appropriate treatment for shoulder instability. These findings also suggest that we should attempt to maintain/restore normal glenohumeral anatomy and implement other forms of treatment such as physical therapy prior to the utilization of surgical correction. In light of these findings, we plan to enroll patients that have received physical therapy for shoulder instability to compare the biomechanical changes associated with its use to that of surgical intervention. The main limitation of this study is a small sample size. However, we will continue to add patients to strengthen our current conclusions and reveal other minor biomechanical changes. Paper #192: Glenoid Morphology after Arthroscopic Osseous Bankart Repair for Recurrent Anterior Glenohumeral Instability: A 5- to 8-Year Follow-up SOUICHIROU KITAYAMA, MD, JAPAN PRESENTING AUTHOR HIROYUKI SUGAYA, MD, JAPAN NORIMASA TAKAHASHI, MD, JAPAN NOBUAKI KAWAI, MD, JAPAN MOTOKI TANAKA, MD, JAPAN MORIHITO TOKAI, MD, JAPAN WATARU IWAMOTO, MD, JAPAN KAZUNORI YASUDA, MD, PHD, JAPAN $ Funabashi Orthopaedic Hospital, Funabashi, Chiba, Japan
SUMMARY Arthroscopic osseous Bankart repair is an effective procedure especially for shoulders with significant bone loss. The Purpose of this study was to assess the clinical results after this procedure over at least 5 years. Arthroscopic osseous Bankart repair can be expected to produce a successful outcome without recurrence once bony union is obtained. Glenoid morphology can be almost normalized. ABSTRACT DATA Introduction: Arthroscopic osseous Bankart repair was introduced almost a decade ago and, although technically demanding in some specific cases, not a few surgeons recognized the effectiveness of this procedure especially for