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(iii) Principles of repair
(iii) Principles of Repair
J. Gillquist
Introduction
ligaments ruptured and a more serious instability. In the typical accident the player will notice a sudden pop in the knee as if something ruptured. The knee gives way and he/she falls. Usually the player is unable to walk and cannot continue to play. A swelling follows within minutes to a few hours and the athlete seeks medical attention. Aspiration of the knee will reveal a haemarthrosis which is necessary for an adequate examination of stability. A well-trained examiner will find the Lachman sign positive and also an increased valgus or varus laxity if the respective ligaments are injured as well. An acute knee X-ray is important to exclude fractures. Within the next 24-48 h a properly performed arthroscopy or a magnetic resonance imaging scan will demonstrate the correct diagnosis. We prefer arthroscopy since concomitant meniscal lesions can be diagnosed and treated with a high accuracy. 5-8
Knee ligament injuries are a common cause of disability in the young athlete. The risk of a serious knee injury is especially high in teamsports like soccer, handball, basketball, volleyball, American football and rugby. The reason for the frequently occurring permanent disability after knee ligament injuries is often incomplete diagnosis and insufficient initial treatment but the severity of the primary injury also plays an important role. The primary injury in acute tears of the anterior cruciate ligament often includes subchondral compression fractures especially in the lateral femoral condyle. I, 2 Delay in the diagnosis and treatment of some injury components will also lead to unacceptable results. It is considered that the 'golden opportunity' for treatment of these injuries is in the acute phase. However, problems with arthrofibrosis after acute treatment of anterior cruciate ligament (ACL) ruptures have led some US authors to recommend a delay of surgery of up to 6 months, a'4 This is unfortunate because at that time primary repair is impossible due to atrophy of the remaining ligament stumps.
Indications for Acute Ligament Repair Acute ligament repair is indicated for young sportsactive individuals who clearly state that they want to continue with their sport. We feel that there is a strong indication for repair in the active individual between 15 and 30 years of age. Between 30 and 40 there is a relative indication in a fit individual who strongly desires to continue on a high activity level. Patients over the age of 40 rarely need knee ligament surgery. In patients below 20, the indication is often strong irrespective of the activity level since they usually do not know what activity level they may want within a year of two. Primary treatment is indicated before closure of the epiphyses if drilling through the growth plate can be avoided. These age limits are of course subjective and the indication for treatment needs to be considered individually. In all these groups the indication for surgery gets stronger with the more
Diagnosis of Acute Knee Ligament Injuries The history of an acute serious knee ligament tear is important. A tear of the ACL and the medial ligament complex is the most common injury. This is only infrequently a contact injury. The player is usually on his own in a deceleration motion, either landing from a jump or turning rapidly to one side. If contact is involved, the injury gets more complex with more
Jan Gillquist MD, PhD, Professor of Sports Medicine, Department of Orthopedics, University Hospital, 58185 Link6ping, Sweden. Current Orthopaedics (1993)7, 90-93
© 1993LongmanGroup UK Ltd
90
PRINCIPLES OF REPAIR
complex injury involving more ligaments and greater instability. Operation may be indicated even in the older age group in patients with a knee dislocation. In a low activity individual a complex injury may be treated by repair of the extra-articular ligaments but leaving the cruciates without repair.
Operation of Acute Knee Ligament Ruptures The acute arthroscopy is used to treat any concomitant meniscal lesions. In acute cases we have found medial and lateral meniscus lesions to be equally c o m m o n ) About equal numbers of meniscus tears can be left alone, repaired or removed. Short longitudinal peripheral tears in stable menisci (probe !) and partial tears can be left without t r e a t m e n t ) ,9 Repair is done on menisci with an intact body but ruptured periphery. Arthroscopic or open repair is chosen depending on the surgeon's preference. Intrasubstance tears are partially removed arthroscopically. Usually the meniscus periphery can be left intact in these cases. After the arthroscopy an open repair of the involved ligaments is performed.
Anterior cruciate ligament Avulsion of the ligament from the femoral or tibial end is uncommon but may occur in the young individual. This tear is repaired by reattaching the bone fragment if it is present. It is important to countersink the fragment slightly in order to tension the stretched ligament. A bone fragment can be fixed by wires, pins or small screws (AO navicular screws). A pure ligament avulsion from the bony surface is extremely infrequent. Usually all ligaments without a bone fragment are too short to reach to the proper insertion place. Most commonly the ACL is ruptured
Figure---Augmentation of the repaired anterior cruciate with a 10 mm strip from the ileotibial band.
91
in the midsubstance with severely fragmented ends (mop end tear). This tear cannot be repaired successfully. It has been well shown that complete tears of the ACL do not heal even under experimental circumstances. 1° In these cases a biologic augmentation is needed to bridge the defect in the ligament. Biologic augmentation improves the end results both in experiments n and clinically. 12, ~a Our repair technique involves suturing the distal stump of the ACL as far as possible towards its normal femoral insertion site. The defect which is about 1 cm is bridged by a 12 mm wide strip from the ileo-tibial band (ITB). The strip is taken through a separate lateral incision from the central part of the ITB. It is 20 cm long and has a distal base. The proximal end is brought through a drill hole in the lateral femoral condyle to the femoral ACL insertion and then down on top of the sutured ACL and stapled to the anterior aspect of the tibia. The strip is attached to the sutured ACL by a few resorbable sutures (Fig.). The incision in the ITB should be closed. Since the original attachments of the ACL are used, no isometry measurement is necessary. So-called notchplasty is done only if the anterior outlet of the notch is stenotic ( < 20 mm width). In such a case it is important to limit the notchplasty to the margins of the femoral notch. This repair technique gives superior results compared to conservative treatment and compared to suturing of the ACL stumps alone, ~ and can be expected to result in about 70% good/excellent knee function at 4 years postoperatively. The stability is improved with about 70% having the same stability as in the normal knee. About 70% of the patients can be expected to return to competitive sports, instead o f the ITB, a strip from the medial retinaculum may be used for augmentation o f the sutured ACL. This technique has equally good results, la Other authors advocate primary ACL reconstruction using a patellar tendon strip, for example. 14 This procedure is the same as in a case with an old ACL rupture. The reconstruction is done with a special drill-guide system TM tG through a small medial miniarthrotomy with the knee in 90 ° of flexion. The guide is designed to make it easier to find the proper femoral insertion point. All retractors are removed and the tibia placed in neutral rotation. The patient's foot is controlled by the surgeon. The guide is inserted and its head wedged in between the tibial spine and the roof of the notch. The alignment of the guide in the frontal plane should be about 20 ° to the long axis of the femur. A 2.5 mm guide pin is drilled straight through and the guide removed. The tibial tunnel and the distal 3 cm of the femoral tunnel are reamed to 8 mm diameter. The remaining part of the femoral tunnel is reamed to 5 ram. The 'isometry' curve is registered at this point using a 10 x 2 m m cotton trial ligament. The purpose of the registration is simply to establish the point of lowest tension in the graft and the shape of the curve. This is used later when the real graft is preloaded. Excessive change in ligament length
92
CURRENT ORTHOPAEDICS--MINI-SYMPOSIUM: KNEE LIGAMENT INJURIES
(> 3 mm) may depend on incorrect positioning of the tunnels, severe associated ligament lesions or severe cartilage damage. Increase in ligament length from extension to flexion must be avoided. This is usually a sign of a too anterior femoral tunnel. When one is uncertain of the best placement of the tunnels it is best to check isometry with the 2.5 mm pilot holes. Then non-isometry can be corrected by moving the pilot holes appropriately before reaming the tunnels to a larger diameter. The graft can be removed from the patellar tendon with the knee in extension or in flexion but one can use a smaller skin incision in extension. A 10 mm central strip of the patellar tendon is delineated with 8 x 20 mm bone blocks. Two 2 mm holes are drilled in the bone fragments. Number 1 Mersilene sutures are inserted through the holes in the fragments. The proximal bone/tendon junction can be augmented with artificial material. The tendon strip is soaked in saline with antibiotics and then pulled up into the femoral tunnel. The proximal bone plug should be completely inside the 8 mm part of the tunnel with the cortical side facing backwards. The augmentation device and/or the sutures are fixed on the external cortex of the femur with one staple. The distal end of the tendon strip is pulled out through the tibial tunnel and preloaded to about 40 N using the spring gauge at a flexion angle half way between the lowest point of the 'isometry' curve and full extension. Our recent studies indicate that fixing the graft under tension at the lowest point of the isometry curve will increase the risk of recurring instability. Cycling the tendon threefour times before applying the final tension will diminish stress relaxation. The remaining A-P displacement can be measured with a laxity tester (OSI Inc Hayward CA, USA) at this stage. The distal end of the graft is fixed under appropriate tension with one staple with the knee at the proper flexion angle according to the isometry curve. This is a more traumatising technique than augmented repair and the results have not been shown to be superior. An increased rate of arthrofibrosis after acute reconstruction with a bone-patellar tendonbone substitute has been described? ,4 This does not seem to be a problem with the two repairaugmentation techniques described above?
Medial ligament Tears of the medial collateral ligament (MCL) in connection with ACL ruptures should be repaired. Isolated tears can be treated conservatively.17 It is important to verify that the patient does not have ruptured menisci. Repair aims at approximation of torn ends of the ligament by sutures. Careful dissection of the anatomy on the medial side of the joint is necessary. The superficial and the deep portions of the MCL should be visualized. One must remember that the ruptures often occur in the joint line in the deep portion and close to the distal
attachment in the superficial portion. The posterior oblique ligament should be identified separately. Tears often involve the distal attachment immediately above the semi-membranosus tendon, sometimes with avulsion of a bone fragment. The ligament ends are approximated in an anatomic fashion by resorbable sutures. It has been shown experimentally that an approximation of the ruptured ends is all that is necessary. 18 Bony avulsions are attached with suture anchors or staples. On the medial side it is also important to diagnose a possible avulsion of the vastus medialis obliquous (VMO) from the medial epicondyle. The patella will dislocate if the medial retinaculum and the VMO are avulsed. Proper attachment of the ruptured structures to the bony site with suture anchors is important.
Lateral ligament Injury to the lateral side is more rare in my experience. Certain types of violence in soccer, rugby or American football may lead to posterolateral ligament injury. In these cases the arcuate ligament, the popliteus tendon, lateral collateral ligament and possibly the lateral gastrocnemius head can be ruptured. These injuries often occur in the midsubstance of the structures and repair aims at approximating the ends. The arcuate ligament and the posterior capsule may be attached to the bone by suture anchors. The lateral head of the gastrocnemius is usually avulsed from the femur and can be attached accordingly. A rupture of the popliteus tendon close to the muscle belly is impossible to repair whereas avulsion from the femur can be easily attached.
Posterior cruciate ligament Ruptures often occur in the midsubstance of the posterior cruciate ligament (PCL). Avulsion from the tibia occurs rarely especially in the young individual. In a few cases ligament avulsion from the femur can be found. Isolated ruptures in medium to low active individuals can be left alone and treated conservatively. If the patient has a congenital varus knee, problems may occur later especially if the lateral structures are also injured. Repair of the PCL is then indicated. Repair is also indicated in sports active individuals on a competitive level. Repair of midsubstance ruptures is done in a fashion similar to the ACL. For augmentation a resorbable stent or the semi-tendinosus tendon may be used. A stent for augmentation can be easily created by braiding 12 Number 0 sutures. It is important that the decision about operative treatment of the ruptured PCL is made early since the results of repair are usually better than after reconstruction. When dealing with PCL injuries one must be aware of the serious effect on the prognosis by a missed lateral instability. Dealing with chronic varus/posterior/posterolateral instabilities is
PRINCIPLES OF REPAIR
difficult and treatment often only moderately successful.
Rehabilitation after Knee Ligament Repair The repaired structure usually heals slowly. Repaired ligaments regain their fibre orientation and mechanical characteristics under load only partially. The end result is often a mechanically inferior ligament. TM 2o Both over and underload during rehabilitation is detrimental to the end result. Underload slows down the development of strength and other mechanical qualities and overload may stretch out or even rupture the repaired structure. The challenge for the physiotherapist is tremendous. A good knowledge of the operative procedure and of the effect of exercises on the repaired structures is necessary. After an ACL repair the physiotherapist has to avoid overloading the ligament with exercises that provoke an abnormal anterior translation. The physiotherapy needs to include complex motions and sports-like activities. Balance and proprioception as well as the precision of motion need to be trained before an athlete can return to his sport. Eccentric muscle strength is often low, late in the rehabilitation when other muscle qualities are already normal. A low eccentric capacity in the thigh muscles results in problems going down stairs, jumping and running. If this muscle capacity is not trained properly the athlete's ability to decelerate may be severely impaired. Training of a proper gait pattern is important especially with medial or lateral ligament repairs and congenital axis deformities in varus or valgus. In a patient with valgus deformity and a gait with excessiye external rotation of the foot and tibia, a medial repair will stretch out and the joint will soon become unstable again. A varus deformity and a gait with internal rotation will similarly stretch out a lateral repair. A shoe insert may be necessary to help the patient maintain correct alignment during walking and running. Video filming and visual feed-back systems may be necessary. The rehabilitation of extremity function to a competitive sports level may take a long time (more than a year) depending on the individual. Complete rehabilitation is, however, one of the important factors in order to avoid new injuries.
References 1. Mark SP, Fowler P, Vellet D. MRI detected bone lesions in anterior cruciate ligament injured knees. Combined Meeting International Society of the Knee and International Arthroscopy Association, Toronto Canada, abstracts p 30
93
2. Speer KP, Spritzer CE, Bassett FH, Feagin JA, Garrett WE. Osseous injury associated with acute tears of the anterior cruciate ligament. Am J Sports Med 1992; 20:382-389 3. Harner CD, Irrgang J, Paul J, Dearwater S, Fu FH. Loss of motion after anterior cruciate ligament reconstruction. Am J Sports Med 1992; 20:499-506 4. Shelbourne KD, Wilckens JH, Mollabashy A, Decarlo M. Arthrofibrosis in acute cruciate ligament reconstruction. The effect of timing of reconstruction and rehabilitation. Am J Sports Med 1991; 19:332-336 5. Andersson C, Odensten M, Good L, Gillquist J. Surgical or non-surgical treatment of acute rupture of the anterior cruciate ligament. A randomized study with long-term follow-up. J Bone Joint Surg 1989; 71A: 965-974 6. Gillquist J, Hagberg G. A new modification of the technique of arthroscopy of the knee joint. Acta Chir Scand 1976; 142: 123-130 7. Dehaven KE. Diagnosis of acute knee injuries with hemarthrosis. Am J Sports Med 1980; 8 : % 1 4 8. Noyes FR, Bassett RW, Grood ES, Butler DL. Arthroscopy in acute hemarthrosis of the knee. J Bone Joint Surg 1980; 62A: 687-695 9. Weiss CB, Lundberg M, Hamberg P, Dehaven KE, Gillquist J. Nonoperative treatment of stable meniscus lesions. J Bone Joint Surg 1989; 71A: 811-822 10. Amiel D, Kuiper S, Akeson WH. Cruciate ligaments. Response to injury. In: Daniel D, Akleson WH, O'Connor J, ed. Knee ligaments. Structure, function, injury and repair, New York: Raven Press, 1990:365-377 11. Cabaud HE, Rodkey WG, Feagin JA. Experimental studies of acute anterior cruciate ligament injury and repair. Am J Sports Med 1979; 7:18-22 12. Jonsson T, Peterson L, Renstr6m P, Althoff B, Myrhage R. Augmentation with the longitudinal patellar retinaculum in the repair of an anterior cruciate ligament rupture. Am J Sports Med 1989; 17:401-408 13. Jonsson T, Peterson L, Renstr6m P. Anterior cruciate ligament repair with and without augmentation: A prospective 7 year study of 51 patients. Acta Orth Scand 1990; 61:562-566 14. Engebretsen L, Benum P, Fasting O, M61ster A, Strand T. A prospective randomized study of three surgical techniques for treatment of acute ruptures of the anterior cruciate ligament. Am J Sports Med 1990; 18:585-590 15. Odensten M, Gillquist J. A modified technique for anterior cruciate ligament (ACL) surgery using a new drill guide for isometric positioning of the ACL. Clin Orth 1986; 213: 154-158 16. Gillquist J. Reconstruction of the anterior cruciate ligament: Indications, operative technique and rehabilitation. Op Tech in Orth 1992; 2:104-111 17. Indelicato PA. Non-operative treatment of complete tears of the medial collateral ligament of the knee. J Bone Joint Surg 1983; 65A: 323-329 18. Woo S L-Y, Horibe S, Ohland K, Amiel D. The response of ligaments to injury. Healing of the collateral ligaments. In: Daniel D, Akleson WH, O'Connor J, ed. Knee ligaments. Structure, function, injury and repair. New York: Raven Press 1990:351-364 19. Newton PO, Horibe S, Woo S L-Y. Experimental studies on anterior cruciate ligament autografts and allografts. Mechanical studies. In: Daniel D, Akleson WH, O'Connor J, ed. Knee ligaments. Structure, function, injury and repair. New York: Raven Press 1990:38%399 20. Ballock RT, Woo S L-Y, Lyon RM, Hollis JM, Akeson WH. Use of patellar tendon autograft for anterior cruciate ligament reconstruction in the rabbit: A long-term histologic and biomechanical study. J Orth Res 1989; 7 : 4 7 4 4 8 5
J. Gillquist
Introduction
ligaments ruptured and a more serious instability. In the typical accident the player will notice a sudden pop in the knee as if something ruptured. The knee gives way and he/she falls. Usually the player is unable to walk and cannot continue to play. A swelling follows within minutes to a few hours and the athlete seeks medical attention. Aspiration of the knee will reveal a haemarthrosis which is necessary for an adequate examination of stability. A well-trained examiner will find the Lachman sign positive and also an increased valgus or varus laxity if the respective ligaments are injured as well. An acute knee X-ray is important to exclude fractures. Within the next 24-48 h a properly performed arthroscopy or a magnetic resonance imaging scan will demonstrate the correct diagnosis. We prefer arthroscopy since concomitant meniscal lesions can be diagnosed and treated with a high accuracy. 5-8
Knee ligament injuries are a common cause of disability in the young athlete. The risk of a serious knee injury is especially high in teamsports like soccer, handball, basketball, volleyball, American football and rugby. The reason for the frequently occurring permanent disability after knee ligament injuries is often incomplete diagnosis and insufficient initial treatment but the severity of the primary injury also plays an important role. The primary injury in acute tears of the anterior cruciate ligament often includes subchondral compression fractures especially in the lateral femoral condyle. I, 2 Delay in the diagnosis and treatment of some injury components will also lead to unacceptable results. It is considered that the 'golden opportunity' for treatment of these injuries is in the acute phase. However, problems with arthrofibrosis after acute treatment of anterior cruciate ligament (ACL) ruptures have led some US authors to recommend a delay of surgery of up to 6 months, a'4 This is unfortunate because at that time primary repair is impossible due to atrophy of the remaining ligament stumps.
Indications for Acute Ligament Repair Acute ligament repair is indicated for young sportsactive individuals who clearly state that they want to continue with their sport. We feel that there is a strong indication for repair in the active individual between 15 and 30 years of age. Between 30 and 40 there is a relative indication in a fit individual who strongly desires to continue on a high activity level. Patients over the age of 40 rarely need knee ligament surgery. In patients below 20, the indication is often strong irrespective of the activity level since they usually do not know what activity level they may want within a year of two. Primary treatment is indicated before closure of the epiphyses if drilling through the growth plate can be avoided. These age limits are of course subjective and the indication for treatment needs to be considered individually. In all these groups the indication for surgery gets stronger with the more
Diagnosis of Acute Knee Ligament Injuries The history of an acute serious knee ligament tear is important. A tear of the ACL and the medial ligament complex is the most common injury. This is only infrequently a contact injury. The player is usually on his own in a deceleration motion, either landing from a jump or turning rapidly to one side. If contact is involved, the injury gets more complex with more
Jan Gillquist MD, PhD, Professor of Sports Medicine, Department of Orthopedics, University Hospital, 58185 Link6ping, Sweden. Current Orthopaedics (1993)7, 90-93
© 1993LongmanGroup UK Ltd
90
PRINCIPLES OF REPAIR
complex injury involving more ligaments and greater instability. Operation may be indicated even in the older age group in patients with a knee dislocation. In a low activity individual a complex injury may be treated by repair of the extra-articular ligaments but leaving the cruciates without repair.
Operation of Acute Knee Ligament Ruptures The acute arthroscopy is used to treat any concomitant meniscal lesions. In acute cases we have found medial and lateral meniscus lesions to be equally c o m m o n ) About equal numbers of meniscus tears can be left alone, repaired or removed. Short longitudinal peripheral tears in stable menisci (probe !) and partial tears can be left without t r e a t m e n t ) ,9 Repair is done on menisci with an intact body but ruptured periphery. Arthroscopic or open repair is chosen depending on the surgeon's preference. Intrasubstance tears are partially removed arthroscopically. Usually the meniscus periphery can be left intact in these cases. After the arthroscopy an open repair of the involved ligaments is performed.
Anterior cruciate ligament Avulsion of the ligament from the femoral or tibial end is uncommon but may occur in the young individual. This tear is repaired by reattaching the bone fragment if it is present. It is important to countersink the fragment slightly in order to tension the stretched ligament. A bone fragment can be fixed by wires, pins or small screws (AO navicular screws). A pure ligament avulsion from the bony surface is extremely infrequent. Usually all ligaments without a bone fragment are too short to reach to the proper insertion place. Most commonly the ACL is ruptured
Figure---Augmentation of the repaired anterior cruciate with a 10 mm strip from the ileotibial band.
91
in the midsubstance with severely fragmented ends (mop end tear). This tear cannot be repaired successfully. It has been well shown that complete tears of the ACL do not heal even under experimental circumstances. 1° In these cases a biologic augmentation is needed to bridge the defect in the ligament. Biologic augmentation improves the end results both in experiments n and clinically. 12, ~a Our repair technique involves suturing the distal stump of the ACL as far as possible towards its normal femoral insertion site. The defect which is about 1 cm is bridged by a 12 mm wide strip from the ileo-tibial band (ITB). The strip is taken through a separate lateral incision from the central part of the ITB. It is 20 cm long and has a distal base. The proximal end is brought through a drill hole in the lateral femoral condyle to the femoral ACL insertion and then down on top of the sutured ACL and stapled to the anterior aspect of the tibia. The strip is attached to the sutured ACL by a few resorbable sutures (Fig.). The incision in the ITB should be closed. Since the original attachments of the ACL are used, no isometry measurement is necessary. So-called notchplasty is done only if the anterior outlet of the notch is stenotic ( < 20 mm width). In such a case it is important to limit the notchplasty to the margins of the femoral notch. This repair technique gives superior results compared to conservative treatment and compared to suturing of the ACL stumps alone, ~ and can be expected to result in about 70% good/excellent knee function at 4 years postoperatively. The stability is improved with about 70% having the same stability as in the normal knee. About 70% of the patients can be expected to return to competitive sports, instead o f the ITB, a strip from the medial retinaculum may be used for augmentation o f the sutured ACL. This technique has equally good results, la Other authors advocate primary ACL reconstruction using a patellar tendon strip, for example. 14 This procedure is the same as in a case with an old ACL rupture. The reconstruction is done with a special drill-guide system TM tG through a small medial miniarthrotomy with the knee in 90 ° of flexion. The guide is designed to make it easier to find the proper femoral insertion point. All retractors are removed and the tibia placed in neutral rotation. The patient's foot is controlled by the surgeon. The guide is inserted and its head wedged in between the tibial spine and the roof of the notch. The alignment of the guide in the frontal plane should be about 20 ° to the long axis of the femur. A 2.5 mm guide pin is drilled straight through and the guide removed. The tibial tunnel and the distal 3 cm of the femoral tunnel are reamed to 8 mm diameter. The remaining part of the femoral tunnel is reamed to 5 ram. The 'isometry' curve is registered at this point using a 10 x 2 m m cotton trial ligament. The purpose of the registration is simply to establish the point of lowest tension in the graft and the shape of the curve. This is used later when the real graft is preloaded. Excessive change in ligament length
92
CURRENT ORTHOPAEDICS--MINI-SYMPOSIUM: KNEE LIGAMENT INJURIES
(> 3 mm) may depend on incorrect positioning of the tunnels, severe associated ligament lesions or severe cartilage damage. Increase in ligament length from extension to flexion must be avoided. This is usually a sign of a too anterior femoral tunnel. When one is uncertain of the best placement of the tunnels it is best to check isometry with the 2.5 mm pilot holes. Then non-isometry can be corrected by moving the pilot holes appropriately before reaming the tunnels to a larger diameter. The graft can be removed from the patellar tendon with the knee in extension or in flexion but one can use a smaller skin incision in extension. A 10 mm central strip of the patellar tendon is delineated with 8 x 20 mm bone blocks. Two 2 mm holes are drilled in the bone fragments. Number 1 Mersilene sutures are inserted through the holes in the fragments. The proximal bone/tendon junction can be augmented with artificial material. The tendon strip is soaked in saline with antibiotics and then pulled up into the femoral tunnel. The proximal bone plug should be completely inside the 8 mm part of the tunnel with the cortical side facing backwards. The augmentation device and/or the sutures are fixed on the external cortex of the femur with one staple. The distal end of the tendon strip is pulled out through the tibial tunnel and preloaded to about 40 N using the spring gauge at a flexion angle half way between the lowest point of the 'isometry' curve and full extension. Our recent studies indicate that fixing the graft under tension at the lowest point of the isometry curve will increase the risk of recurring instability. Cycling the tendon threefour times before applying the final tension will diminish stress relaxation. The remaining A-P displacement can be measured with a laxity tester (OSI Inc Hayward CA, USA) at this stage. The distal end of the graft is fixed under appropriate tension with one staple with the knee at the proper flexion angle according to the isometry curve. This is a more traumatising technique than augmented repair and the results have not been shown to be superior. An increased rate of arthrofibrosis after acute reconstruction with a bone-patellar tendonbone substitute has been described? ,4 This does not seem to be a problem with the two repairaugmentation techniques described above?
Medial ligament Tears of the medial collateral ligament (MCL) in connection with ACL ruptures should be repaired. Isolated tears can be treated conservatively.17 It is important to verify that the patient does not have ruptured menisci. Repair aims at approximation of torn ends of the ligament by sutures. Careful dissection of the anatomy on the medial side of the joint is necessary. The superficial and the deep portions of the MCL should be visualized. One must remember that the ruptures often occur in the joint line in the deep portion and close to the distal
attachment in the superficial portion. The posterior oblique ligament should be identified separately. Tears often involve the distal attachment immediately above the semi-membranosus tendon, sometimes with avulsion of a bone fragment. The ligament ends are approximated in an anatomic fashion by resorbable sutures. It has been shown experimentally that an approximation of the ruptured ends is all that is necessary. 18 Bony avulsions are attached with suture anchors or staples. On the medial side it is also important to diagnose a possible avulsion of the vastus medialis obliquous (VMO) from the medial epicondyle. The patella will dislocate if the medial retinaculum and the VMO are avulsed. Proper attachment of the ruptured structures to the bony site with suture anchors is important.
Lateral ligament Injury to the lateral side is more rare in my experience. Certain types of violence in soccer, rugby or American football may lead to posterolateral ligament injury. In these cases the arcuate ligament, the popliteus tendon, lateral collateral ligament and possibly the lateral gastrocnemius head can be ruptured. These injuries often occur in the midsubstance of the structures and repair aims at approximating the ends. The arcuate ligament and the posterior capsule may be attached to the bone by suture anchors. The lateral head of the gastrocnemius is usually avulsed from the femur and can be attached accordingly. A rupture of the popliteus tendon close to the muscle belly is impossible to repair whereas avulsion from the femur can be easily attached.
Posterior cruciate ligament Ruptures often occur in the midsubstance of the posterior cruciate ligament (PCL). Avulsion from the tibia occurs rarely especially in the young individual. In a few cases ligament avulsion from the femur can be found. Isolated ruptures in medium to low active individuals can be left alone and treated conservatively. If the patient has a congenital varus knee, problems may occur later especially if the lateral structures are also injured. Repair of the PCL is then indicated. Repair is also indicated in sports active individuals on a competitive level. Repair of midsubstance ruptures is done in a fashion similar to the ACL. For augmentation a resorbable stent or the semi-tendinosus tendon may be used. A stent for augmentation can be easily created by braiding 12 Number 0 sutures. It is important that the decision about operative treatment of the ruptured PCL is made early since the results of repair are usually better than after reconstruction. When dealing with PCL injuries one must be aware of the serious effect on the prognosis by a missed lateral instability. Dealing with chronic varus/posterior/posterolateral instabilities is
PRINCIPLES OF REPAIR
difficult and treatment often only moderately successful.
Rehabilitation after Knee Ligament Repair The repaired structure usually heals slowly. Repaired ligaments regain their fibre orientation and mechanical characteristics under load only partially. The end result is often a mechanically inferior ligament. TM 2o Both over and underload during rehabilitation is detrimental to the end result. Underload slows down the development of strength and other mechanical qualities and overload may stretch out or even rupture the repaired structure. The challenge for the physiotherapist is tremendous. A good knowledge of the operative procedure and of the effect of exercises on the repaired structures is necessary. After an ACL repair the physiotherapist has to avoid overloading the ligament with exercises that provoke an abnormal anterior translation. The physiotherapy needs to include complex motions and sports-like activities. Balance and proprioception as well as the precision of motion need to be trained before an athlete can return to his sport. Eccentric muscle strength is often low, late in the rehabilitation when other muscle qualities are already normal. A low eccentric capacity in the thigh muscles results in problems going down stairs, jumping and running. If this muscle capacity is not trained properly the athlete's ability to decelerate may be severely impaired. Training of a proper gait pattern is important especially with medial or lateral ligament repairs and congenital axis deformities in varus or valgus. In a patient with valgus deformity and a gait with excessiye external rotation of the foot and tibia, a medial repair will stretch out and the joint will soon become unstable again. A varus deformity and a gait with internal rotation will similarly stretch out a lateral repair. A shoe insert may be necessary to help the patient maintain correct alignment during walking and running. Video filming and visual feed-back systems may be necessary. The rehabilitation of extremity function to a competitive sports level may take a long time (more than a year) depending on the individual. Complete rehabilitation is, however, one of the important factors in order to avoid new injuries.
References 1. Mark SP, Fowler P, Vellet D. MRI detected bone lesions in anterior cruciate ligament injured knees. Combined Meeting International Society of the Knee and International Arthroscopy Association, Toronto Canada, abstracts p 30
93
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