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Is an ACL reconstruction outcome age dependent?
360
ABSTRACTS
knots in the simple suture configuration likely contributed to its superior strength characteristics compared to the mattress suture configuration.
Tension Mismatch in Rotator Cuff Repairs: A Cause of "Controlled Failure" of Repair in Cyclic Loading. Stephen S. Burkhart, Todd C. Johnson, Michael A. Wirth, Kari Athanasiou, George Constantinides, and Gabriele Niederaur. San Antonio, Texas, U.S.A. Crescent-shaped rotator cuff defects were created in 16 cadaver specimens by excising, in each specimen, a 1 x 2 cm crescent of tendon that comprised the supraspinatus insertion and a portion of the infraspinatus insertion onto the greater tuberosity of the humerus. This effectively shortened the muscle-tendon unit acting at the center of the defect, in comparison with the muscle-tendon units at the periphery of the defect. The defect was repaired by transosseous simple sutures (#2 cottony Dacron in 8 specimens, and #2 Ethibond in 8 specimens) placed in a precisely standardized manner. Each repair was then cyclically loaded by a servohydraulic materials test system activator at a rate of 33 mm/sec to a load of 180 N, which is roughly equal to 50% of a maximal contraction of the involved muscles in an average human adult. A progressive gap in the repair was noted in each specimen. A 5-mm gap developed at an average of 24.94 cycles (33.00 cycles for Dacron and 16.88 for Ethibond). A 10-mm gap developed in all specimens at an average of 182.75 cycles (195.88 for Dacron and 169.63 for Ethibond). In three intact controls without defects in the rotator cuff, no gaps developed in any of the three specimens, each of which was cycled greater than 3,500 times to 180 N. This study suggests that rotator cuff tears that are repaired with a "tension mismatch" will undergo gradual failure with physiological cyclic loading until the normal resting length of the muscle-tendon unit is restored. This "controlled failure" may explain residual defects that have been demonstrated by ultrasonography and by arthrography in patients with "successful" rotator cuff repairs.
Outpatient Anterior Cruciate Ligament Reconstruction. Erin A. Felger and John C. Pritchard. Chicago, Illinois, and Fort Wayne, Indiana, U.S.A. We designed a prospective study at an outpatient surgery center to determine the effectiveness of arthroscopically assisted anterior cruciate ligament reconstruction (ACL) using middle third patellar tendon Arthroscopy, Vol 12, No 3, 1996
autograft. The outcome of the surgery and the cost effectiveness of the procedure were evaluated. Forty-eight of 57 patients who underwent this surgery performed by a single surgeon returned for a complete follow-up at a minimum of 6 months (mean 14 months). Postoperative follow-up included the KT1000 arthrometric evaluation, the International Knee Documentation Committee Form (IKDC), and the Lysholm Knee Scoring Scale. Results for the KT-1000 were excellent with a mean maximum difference of 2.0 mm. Seventy-five percent of patients had < 3 mm maximum difference. Eight trace Lachmans and one positive pivot shift were noted. No one had any significant loss of extension compared with the contralateral side, and only 3 patients had some degree of loss of flexion on the affected side. Patients completed a subjective evaluation of their experience with the surgery and with the outpatient surgery center. Their responses ranged from excellent to poor with 94% of patients being pleased with their outcome. Two complications were noted, a patellar fracture and a superficial portal infection, both of which responded to appropriate treatment. In our community, cost savings were substantial and statistically significant (P < .01) at more than $3,000 per patient when compared with the cost of surgery with overnight stay at an inpatient institution. Overall, our complication rate and results were comparable to values in similar studies; by doing outpatient surgery, the expected outcome was not jeopardized. The data supported a positive outcome of surgical success, knee function, and cost for this procedure being performed in the outpatient surgery center.
Is An ACL Reconstruction Outcome Age Dependent? F. Alan Barber, David A. McGuire, Burton F. Elrod, and Lonnie E. Paulos. Plano, Texas, Anchorage, Alaska, Nashville, Tennessee, and Salt Lake City, Utah, U.S.A.
Introduction: The selection of the treatment for a torn anterior cruciate ligament must consider many factors including the patient's activity level, instability, and functional impairment. Previous concerns about the advisability of an ACL reconstruction in older patients include healing delays, rehabilitation difficulties, stiffness, arthritis, and the actual athletic demands. Concerns about graft site morbidity have lead some to use allografts in older patients. The purpose of this study was to evaluate the outcome of ACL reconstructions in patients 40 years old and older compared to those 39 years old or less done during the same time period.
ABSTRACTS Methods: A series of patients undergoing ACL reconstruction between 1992 and 1994 were pre and postoperatively assessed with Lysholm, Tegner, KT, radiographic, and clinical examinations. For analysis they were divided into two groups: those 40 and older and those 39 and younger. Results: Group 1 was 33 patients (19 men, 14 women) with an average age of 44 (range 40-52) who underwent ACL reconstruction an average of 50 months after the initial injury. Allografts were used in 64%. Preoperative evaluation indicated marked clinical laxity (Lachman 2+ or 3+ in 94%, pivot shift at least 2+ in 79% and 1 + in 21%), instrumented laxity (avg. KT Man Max, 6.7 mm), and subjective problems (avg. Lysholm, 55; avg. Tegner, 2.3). Radiographic Fairbanks changes were absent. Group 2 was 169 patients (119 men, 50 women) with an average age of 27 (range 16-39) who underwent ACL reconstruction during this same period using the same procedure and accelerated rehabilitation program. Allografts were used in 38%. Time from injury to surgery for Group 2 was 28 months. The Group 2 preoperative instability and intake data were not statistically different from Group 1. Average followup was 21 months (range 12-36) for Group 1 and 19 months (range 12-39) for Group 2. Both groups showed significant improvement in all parameters at 24 months followup. In the 40 and over group, Lysholm scores averaged 95, Tegner scores averaged 5.7 (range 4-7), average KT Man Max. was 1.5, Lachman was 0 in 80% and 1+ in 16%, pivot shift was 0 in 68% and 1 + in 26%. Using Lysholm criteria, 74% had excellent, 16% good, and 10% fair results. Motion at 2 years was evaluated and none had > 5 ° loss of extension or >10 ° loss of flexion. One patient in both groups demonstrated mild Fairbanks changes at the 2-year followup. At follow-up in the under 40 group, Lysholm scores averaged 95, Tegner scores averaged 6.1 (range 2-9), average KT Man Max. was 1.7, Lachman was 0 in 69% and 1 + in 27%, pivot shift was 0 in 83% and 1+ in 16%. Using Lysholm criteria, 71% had excellent, 20% good, 8% fair, and 1% poor results. Loss of motion was evaluated and none had > 5 ° loss of extension while 4% had >10 ° loss of flexion. Radiographic Fairbanks changes were not present at 2 years. Discussion and Conclusion: The concerns about scarring, loss of motion, donor site morbidity, arthritis, and delayed healing as related to those over 40 are not supported by these data. The outcomes between these groups are the same and fail to establish the age of 40 as a barrier to successful ACL reconstruction. Recent Suture Anchor Developments F. Alan Bar-
361
ber, Morley Herbert, and James N. Click. Plant, and Dallas, Texas, U.S.A. Introduction: Suture anchors are used to attach tendons and ligaments to bone in the shoulder, elbow, hand, knee, ankle and foot. New instruments, surgical techniques, and anchors have expanded the arthroscopic surgeons options. Two new areas of anchor development are bioabsorable anchors and " m i n i " anchors. The purpose of this study is to evaluate the new anchors belonging to these two groups as to pull out strength, mode of failure, and suture size acceptance to provide the surgeon some objective data for anchor selection. Methods: Biodegradable anchors are of PGA, PLLA, or a PGA-PLLA copolymer. This group includes the Bioanchor, ESP, LactoSorb, Biofix, and Stealth. " M i n i " anchors are defined as those with drill holes or minor diameters of <2.2 mm. These include the miniRevo, miniHarpoon, miniMitek, Fastin 3, Statak 1.5 and 2.5, SB, PeBA 3, Fastak, and Bioanchor. A comparison of these anchors was done using an established protocol in fresh porcine femur. 10 samples of each anchor were inserted into three different test areas: diaphyseal cortex, metaphyseal cortex, and a cancellous bone "trough". The anchors, threaded with stainless steel wire, wire braid, or Spectra suture, were subjected to a tensile stress parallel to the axis of insertion at a rate of 12.5 mm/sec until failure. Failure strength, failure mode, eyelet size, and minor diameters were recorded. Results: Except for the Bioanchor, biodegradable anchors are larger (2.9 to 3.5 mm) to compensate for their lower strength relative to metal. Their predominant failure mode is pull out indicating that the eyelets are adequately reinforced. These biodegradable anchors failed at loads greater than the strength of #2 Ethibond and were not statistically different. Differences exist in associated instrumentation, size, and material. All will accommodate #2 suture. Minianchors (except the Bioanchor) are metal and include screw (Fastak, Fastin, miniRevo, Stataks) and nonscrew designs (Bioanchor, miniHarpoon, miniMitek, SB, PeBA). Screw designs perform well and fail by suture eyelet cutout (or wire breakage). The nonscrew designs (with the exception of the SB) fail usually by anchor pullout. The SB (a toggle anchor) did not pull out. Failure was evenly divided between wire breakage and wire cutout. Minianchors that did not reach the 30 pound failure level in all tested environments were the miniMitek and Statak 1.5. The minianchors are also able to accommodate a #2 suture. Arthroscopy, Vol 12, No 3, 1996
ABSTRACTS
knots in the simple suture configuration likely contributed to its superior strength characteristics compared to the mattress suture configuration.
Tension Mismatch in Rotator Cuff Repairs: A Cause of "Controlled Failure" of Repair in Cyclic Loading. Stephen S. Burkhart, Todd C. Johnson, Michael A. Wirth, Kari Athanasiou, George Constantinides, and Gabriele Niederaur. San Antonio, Texas, U.S.A. Crescent-shaped rotator cuff defects were created in 16 cadaver specimens by excising, in each specimen, a 1 x 2 cm crescent of tendon that comprised the supraspinatus insertion and a portion of the infraspinatus insertion onto the greater tuberosity of the humerus. This effectively shortened the muscle-tendon unit acting at the center of the defect, in comparison with the muscle-tendon units at the periphery of the defect. The defect was repaired by transosseous simple sutures (#2 cottony Dacron in 8 specimens, and #2 Ethibond in 8 specimens) placed in a precisely standardized manner. Each repair was then cyclically loaded by a servohydraulic materials test system activator at a rate of 33 mm/sec to a load of 180 N, which is roughly equal to 50% of a maximal contraction of the involved muscles in an average human adult. A progressive gap in the repair was noted in each specimen. A 5-mm gap developed at an average of 24.94 cycles (33.00 cycles for Dacron and 16.88 for Ethibond). A 10-mm gap developed in all specimens at an average of 182.75 cycles (195.88 for Dacron and 169.63 for Ethibond). In three intact controls without defects in the rotator cuff, no gaps developed in any of the three specimens, each of which was cycled greater than 3,500 times to 180 N. This study suggests that rotator cuff tears that are repaired with a "tension mismatch" will undergo gradual failure with physiological cyclic loading until the normal resting length of the muscle-tendon unit is restored. This "controlled failure" may explain residual defects that have been demonstrated by ultrasonography and by arthrography in patients with "successful" rotator cuff repairs.
Outpatient Anterior Cruciate Ligament Reconstruction. Erin A. Felger and John C. Pritchard. Chicago, Illinois, and Fort Wayne, Indiana, U.S.A. We designed a prospective study at an outpatient surgery center to determine the effectiveness of arthroscopically assisted anterior cruciate ligament reconstruction (ACL) using middle third patellar tendon Arthroscopy, Vol 12, No 3, 1996
autograft. The outcome of the surgery and the cost effectiveness of the procedure were evaluated. Forty-eight of 57 patients who underwent this surgery performed by a single surgeon returned for a complete follow-up at a minimum of 6 months (mean 14 months). Postoperative follow-up included the KT1000 arthrometric evaluation, the International Knee Documentation Committee Form (IKDC), and the Lysholm Knee Scoring Scale. Results for the KT-1000 were excellent with a mean maximum difference of 2.0 mm. Seventy-five percent of patients had < 3 mm maximum difference. Eight trace Lachmans and one positive pivot shift were noted. No one had any significant loss of extension compared with the contralateral side, and only 3 patients had some degree of loss of flexion on the affected side. Patients completed a subjective evaluation of their experience with the surgery and with the outpatient surgery center. Their responses ranged from excellent to poor with 94% of patients being pleased with their outcome. Two complications were noted, a patellar fracture and a superficial portal infection, both of which responded to appropriate treatment. In our community, cost savings were substantial and statistically significant (P < .01) at more than $3,000 per patient when compared with the cost of surgery with overnight stay at an inpatient institution. Overall, our complication rate and results were comparable to values in similar studies; by doing outpatient surgery, the expected outcome was not jeopardized. The data supported a positive outcome of surgical success, knee function, and cost for this procedure being performed in the outpatient surgery center.
Is An ACL Reconstruction Outcome Age Dependent? F. Alan Barber, David A. McGuire, Burton F. Elrod, and Lonnie E. Paulos. Plano, Texas, Anchorage, Alaska, Nashville, Tennessee, and Salt Lake City, Utah, U.S.A.
Introduction: The selection of the treatment for a torn anterior cruciate ligament must consider many factors including the patient's activity level, instability, and functional impairment. Previous concerns about the advisability of an ACL reconstruction in older patients include healing delays, rehabilitation difficulties, stiffness, arthritis, and the actual athletic demands. Concerns about graft site morbidity have lead some to use allografts in older patients. The purpose of this study was to evaluate the outcome of ACL reconstructions in patients 40 years old and older compared to those 39 years old or less done during the same time period.
ABSTRACTS Methods: A series of patients undergoing ACL reconstruction between 1992 and 1994 were pre and postoperatively assessed with Lysholm, Tegner, KT, radiographic, and clinical examinations. For analysis they were divided into two groups: those 40 and older and those 39 and younger. Results: Group 1 was 33 patients (19 men, 14 women) with an average age of 44 (range 40-52) who underwent ACL reconstruction an average of 50 months after the initial injury. Allografts were used in 64%. Preoperative evaluation indicated marked clinical laxity (Lachman 2+ or 3+ in 94%, pivot shift at least 2+ in 79% and 1 + in 21%), instrumented laxity (avg. KT Man Max, 6.7 mm), and subjective problems (avg. Lysholm, 55; avg. Tegner, 2.3). Radiographic Fairbanks changes were absent. Group 2 was 169 patients (119 men, 50 women) with an average age of 27 (range 16-39) who underwent ACL reconstruction during this same period using the same procedure and accelerated rehabilitation program. Allografts were used in 38%. Time from injury to surgery for Group 2 was 28 months. The Group 2 preoperative instability and intake data were not statistically different from Group 1. Average followup was 21 months (range 12-36) for Group 1 and 19 months (range 12-39) for Group 2. Both groups showed significant improvement in all parameters at 24 months followup. In the 40 and over group, Lysholm scores averaged 95, Tegner scores averaged 5.7 (range 4-7), average KT Man Max. was 1.5, Lachman was 0 in 80% and 1+ in 16%, pivot shift was 0 in 68% and 1 + in 26%. Using Lysholm criteria, 74% had excellent, 16% good, and 10% fair results. Motion at 2 years was evaluated and none had > 5 ° loss of extension or >10 ° loss of flexion. One patient in both groups demonstrated mild Fairbanks changes at the 2-year followup. At follow-up in the under 40 group, Lysholm scores averaged 95, Tegner scores averaged 6.1 (range 2-9), average KT Man Max. was 1.7, Lachman was 0 in 69% and 1 + in 27%, pivot shift was 0 in 83% and 1+ in 16%. Using Lysholm criteria, 71% had excellent, 20% good, 8% fair, and 1% poor results. Loss of motion was evaluated and none had > 5 ° loss of extension while 4% had >10 ° loss of flexion. Radiographic Fairbanks changes were not present at 2 years. Discussion and Conclusion: The concerns about scarring, loss of motion, donor site morbidity, arthritis, and delayed healing as related to those over 40 are not supported by these data. The outcomes between these groups are the same and fail to establish the age of 40 as a barrier to successful ACL reconstruction. Recent Suture Anchor Developments F. Alan Bar-
361
ber, Morley Herbert, and James N. Click. Plant, and Dallas, Texas, U.S.A. Introduction: Suture anchors are used to attach tendons and ligaments to bone in the shoulder, elbow, hand, knee, ankle and foot. New instruments, surgical techniques, and anchors have expanded the arthroscopic surgeons options. Two new areas of anchor development are bioabsorable anchors and " m i n i " anchors. The purpose of this study is to evaluate the new anchors belonging to these two groups as to pull out strength, mode of failure, and suture size acceptance to provide the surgeon some objective data for anchor selection. Methods: Biodegradable anchors are of PGA, PLLA, or a PGA-PLLA copolymer. This group includes the Bioanchor, ESP, LactoSorb, Biofix, and Stealth. " M i n i " anchors are defined as those with drill holes or minor diameters of <2.2 mm. These include the miniRevo, miniHarpoon, miniMitek, Fastin 3, Statak 1.5 and 2.5, SB, PeBA 3, Fastak, and Bioanchor. A comparison of these anchors was done using an established protocol in fresh porcine femur. 10 samples of each anchor were inserted into three different test areas: diaphyseal cortex, metaphyseal cortex, and a cancellous bone "trough". The anchors, threaded with stainless steel wire, wire braid, or Spectra suture, were subjected to a tensile stress parallel to the axis of insertion at a rate of 12.5 mm/sec until failure. Failure strength, failure mode, eyelet size, and minor diameters were recorded. Results: Except for the Bioanchor, biodegradable anchors are larger (2.9 to 3.5 mm) to compensate for their lower strength relative to metal. Their predominant failure mode is pull out indicating that the eyelets are adequately reinforced. These biodegradable anchors failed at loads greater than the strength of #2 Ethibond and were not statistically different. Differences exist in associated instrumentation, size, and material. All will accommodate #2 suture. Minianchors (except the Bioanchor) are metal and include screw (Fastak, Fastin, miniRevo, Stataks) and nonscrew designs (Bioanchor, miniHarpoon, miniMitek, SB, PeBA). Screw designs perform well and fail by suture eyelet cutout (or wire breakage). The nonscrew designs (with the exception of the SB) fail usually by anchor pullout. The SB (a toggle anchor) did not pull out. Failure was evenly divided between wire breakage and wire cutout. Minianchors that did not reach the 30 pound failure level in all tested environments were the miniMitek and Statak 1.5. The minianchors are also able to accommodate a #2 suture. Arthroscopy, Vol 12, No 3, 1996