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Arthroscopic meniscal repair with fibrin clot of complete radial tears of the lateral meniscus in the avascular zone
Arthroscopic Meniscal Repair With Fibrin Clot of Complete Radial Tears of the Lateral Meniscus in the Avascular Zone Michiel F. van Trommel, M.D., Peter T. Simonian, M.D., Hollis G. Potter, M.D., and Thomas L. Wickiewicz, M.D.
Summary: Peripheral lateral meniscal tears are amenable to arthroscopic meniscal repair. However, the posterolateral aspect of the lateral meniscus adjacent to the popliteus tendon is devoid of penetrating peripheral vessels and therefore difficult to heal. A complete radial split at this site is usually treated with total meniscectomy. We report five cases of a tear of the posterolateral aspect of the lateral meniscus anterior to the popliteus fossa. All patients had a radial split that extended to the popliteus tendon. In all cases, the repair was enhanced with a fibrin clot. Second-look arthroscopy showed that healing of the periphery occurred in all of the cases. All patients returned to their initial level of sports activity. Three of five patients were available for follow-up at an average of 71 months, and magnetic resonance imaging was performed at that time to assess the previously repaired meniscus. All menisci were fully healed and showed no further signs of degeneration. The ability of an exogenous fibrin clot to stimulate and support a reparative response in the avascular portion of the meniscus may represent a potential method of repair. Awareness of the relatively low healing potential of this zone and enhancement of healing opportunities should improve outcome. Key Words: Meniscal repair—Avascular zone—Lateral meniscus—Fibrin clot.
T
he intact meniscus is crucial for maintaining a multitude of normal joint functions, including shock absorption, joint lubrication, and force transmission across the knee joint, by increasing contact area and thereby decreasing contact stress on the articular cartilage.1-3 Meniscal pathology may result in degeneration of articular cartilage.2,4,5 This has been especially true in the case of total lateral meniscectomy in the young athletic patient. Preservation of meniscal tissue when possible, will result in a more optimized clinical outcome.6,7 The decision to repair the meniscus is multifactoFrom The Sports Medicine Service, The Hospital for Special Surgery, affıliated with the New York Hospital-Cornell University Medical College, New York, New York, U.S.A. Address correspondence and reprint requests to Michiel F. van Trommel, M.D., Onze Lieve Vrouwe Gasthuis, Department of Orthopaedics, 1e Oosterparkstraat 279, 1091 HA Amsterdam, The Netherlands. r 1998 by the Arthroscopy Association of North America 0749-8063/98/1404-1632$3.00/0
360
rial.8 Peripheral lateral meniscal tears are amenable to arthroscopic meniscal repair. However, the posterolateral aspect of the lateral meniscus adjacent to the popliteus tendon is devoid of penetrating peripheral vessels (Fig 1),3,9 which would make meniscal repair less appealing. Partial radial tears are easily managed with subtotal meniscectomy but complete radial tears into the popliteus sleeve necessitates total meniscectomy. This report deals with the latter situation (Fig 2A and B).3 Meniscal suture alone may stabilize the tear and stimulate cell proliferation for healing, but it appears to be significantly restricted without an adequate blood supply (Fig 2C).8 Several techniques are described to enhance meniscal healing in avascular zones. These include the use of a fibrin clot, trephination, and growth factors.10-12 Younger patients and athletes are at greater risk for arthritic changes with partial or total meniscectomy.7 In these cases therefore, repair is indicated.
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 14, No 4 (May-June), 1998: pp 360–365
MENISCAL REPAIR WITH FIBRIN CLOT
Due to copyright restrictions, this figure is not available online. Please see the print version.
FIGURE 1. Schematic drawing of the vascularity of the lateral meniscus. The zone anterior to the popliteus fossa is devoid of penetrating vessels. (Reprinted with permission.3 )
We report five cases of a tear of the posterolateral aspect of the lateral meniscus anterior to the popliteus fossa. All patients had a complete radial split that extended to the popliteus tendon. In all cases, the repair was enhanced with a fibrin clot and all had second-look arthroscopy. Three patients were contacted for long-term follow-up (average 71 months) including magnetic resonance imaging (MRI) of the repair site. MATERIALS AND METHODS Technique Repair of the posterolateral aspect of the lateral meniscus anterior to the popliteus fossa was preceded by abrasion of the tear surfaces. Multiple horizontal sutures (0-PDS) were positioned across the tear in an outside-to-inside fashion. The inner sutures were placed first, followed by more peripheral sutures. Before tying the knots, an exogenous fibrin clot was placed in the seam of the tear. One to 2 mL of clot was sufficient to fill the defect. The postoperative protocol constituted of immobilization and nonweightbearing for 3 weeks. The motion was then gradually expanded over the next few weeks with physical therapy. Squatting beyond 90° and
361
running activities were not allowed for 4 months. During this period, the knee was protected with a derotation brace. After 4 to 5 months, sporting activities were resumed. Second-look arthroscopy was performed in all patients at 4 months (range, 3 to 6 months) after the index operation to assess the repaired meniscus. MRI Technique MRI was performed on a 1.5 Tesla unit (Signa; General Electric Medical Systems, Milwaukee, WI), using a send-receive extremity coil. Pulse sequences included coronal spin echo sequences (repetition time TR/echo time msec TE (Ef) 4,000/38; field of view 13 cm; slice thickness 3.5 mm with no interslice gap; matrix 512 ⫻ 256 at two excitations. Sagittal fast spin echo sequences were obtained with TR/TE (msec) 4,000/36; field of view 13 to 18 cm; matrix 256 ⫻ 224 at two excitations, slice thickness 4 mm with no interslice gap. The latter images were obtained with frequency-selective fat suppression (Chemsat; General Electric Medical Systems). High-resolution sagittal images were obtained to evaluate articular cartilage and intrameniscal morphology utilizing TR 4,000/TE 30 msec (Ef); field of view 16 cm; slice thickness 3.5 mm with no interslice gap; matrix 512 ⫻ 256 or 512 ⫻ 384 at two excitations. In the presence of interference screws from concomitant anterior cruciate reconstruction, tailored RF (General Electric Medical Systems) was additionally used to diminish interecho spacing. Meniscal morphology was judged based on the intact appearance of the meniscus, and meniscus was deemed to be healed if there was no fluid imbibition into the substance of the fibrocartilage, as previously reported.13 Fragmentation when present was noted, and the capsular attachments were also evaluated. Note was made if there was concomitant partial meniscectomy. In addition, fast spin echo sequences were used to evaluate the adjacent articular cartilage using a modified Outerbridge classification.14 Clinical Cases Five patients with an average age of 20 years (range, 18 to 22 years) were included. All patients had a history of pain and occasional swelling of the knee following a traumatic sporting injury. The duration of the symptoms averaged 25 months (range, 4 to 79 months). At surgery in all cases, a complete radial split at the level of the popliteus fossa extending from the periphery to the central part of the meniscus was found (zone E, area 0123 according to Cooper,15 Fig 3). A repair was performed with 2 or 3 PDS sutures tied in an outside-to-inside fashion over a fibrin clot (see
362
M. F. VAN TROMMEL ET AL.
FIGURE 2. (A) Schematic drawing of a lateral meniscus. A limited tear in zone 3 can be addressed with a partial meniscectomy (B) A radial split of zone E 0123, i.e., extending from the central part of the lateral meniscus to the popliteus fossa, cannot be treated with a partial meniscectomy because this would separate the posterior and anterior horn. (C) Suturing of the lateral meniscus over a fibrin clot (not drawn) preserves meniscal integrity.
technique session for details). One patient had a torn anterior cruciate ligament (ACL) that was addressed at the same procedure with a bone–patellar tendon–bone graft. In this same patient, trephination of the meniscus
was done to both decompress a meniscal cyst, which was associated with the tear and encourage vascularization. This patient had been symptomatic for 7 months. After the second-look arthroscopy three of five pa-
MENISCAL REPAIR WITH FIBRIN CLOT
363
Due to copyright restrictions, this figure is not available online. Please see the print version.
FIGURE 3. Different meniscal zones according to Cooper et al.15 P, popliteus tendon. (Reprinted with permission.15 )
tients were followed clinically and radiologically by means of MRI to assess meniscal integrity13 at the repair site with an average follow-up of 71 months (range, 66 to 81 months) (Table 1). Two patients were lost to follow-up. RESULTS All patients had a routine second-look arthroscopy 4 months after the initial treatment (range, 3 to 5 months). At second-look arthroscopy, excellent healing had occurred in 3 of 5 patients. Of these, in two cases a small area in zone 3 appeared minimally deficient, probably due to a tissue mismatch during the repair, and the residual inner rim of zone 3 was trimmed. In the fourth patient, the inferior part of the tear failed to seal and it was subsequently resected. The superior surface of the lateral meniscus, however, was intact throughout. The fifth patient, who also had an ACL reconstruction and a cyst decompression at the initial procedure, continued to have a fair amount of discomfort before the second-look arthroscopy. The pain was located at the region where the cyst was decompressed and where the sutures for the meniscal repair were placed. At second-look arthroscopy, the meniscus had healed in zone 01 anterior to the
FIGURE 4. Coronal fast spin echo MRI 67 month postoperative indicating full healing (curved arrow) without residual signal hyperintensity. Zone 3 has been trimmed at second-look arthroscopy (straight arrow).
popliteus fossa, but failed to coapt at the 2 and 3 zone, which was resected. At follow-up, he was completely asymptomatic. All patients were able to return to their initial level of sports. Two patients were lost to follow-up after the secondlook arthroscopy. Three patients agreed to have MRI and a clinical re-evaluation of their knee, despite the fact that they were clinically asymptomatic. MRI showed a fully healed meniscus at the repair sites in all cases with no further disruption of the debrided area that previously was addressed at second-look arthroscopy in two of the patients (Fig 4).
TABLE 1. Patient Data Case
Age (y)
Sport
1 2 3 4 5
20 19 18 18 22
Football Running Basketball Basketball Hockey
Time to Symptomatic at Surgery (mo) Second-Look Arthroscopy 79 31 6 4 7
No No No Yes Yes
Results of Second-Look Arthroscopy Inferior part resected Healed Healed Healed Zone 0-1 healed, 2-3 resected
Follow-up Symptomatic Time (mo) at Follow-up N/A N/A 67 81 66
N/A N/A No No No
Results of MRI N/A N/A Healed Healed 0-1 healed
364
M. F. VAN TROMMEL ET AL. DISCUSSION
Many studies have shown healing rates for meniscal repair ranging from 50% to 89%.16-19 To our knowledge, there are no studies determining the healing rate at the avascular zone anterior to the popliteus fossa. Factors to consider when assessing healing rates include location and type of the tear, technique of repair, and stability of the knee. The posterolateral area of the lateral meniscus, zone E, has been noted to be devoid of vasculature.9 Kimura et al.16 found 50% no healing of avascular meniscal zones at second-look arthroscopy. However, their series also included repairs at the central zones (i.e., 2 and 3) of both the medial and lateral meniscus. Several techniques for enhancement of healing have been described. Arnoczky et al.12 documented in an animal model that defects filled with fibrin clot heal through a proliferation of fibrous connective tissue that eventually modulates into fibrocartilaginous tissue. The fibrin clot appears to act as a chemotactic and mitogenic stimulus for reparative cells and provides a scaffolding for the reparative process. A fibrin clot was used in all our cases. In the case of concomitant ACL reconstruction, postoperative hemarthrosis may provide serum proteins, growth factors, and a fibrinous framework to the tear and promote healing. This is analogous to the addition of a fibrin clot to the tear at the time of the repair, and therefore insertion of a fibrin clot may not be necessary. Fibrin clot deposition along with vascular access channels are advances that potentially increase healing rates of meniscal repairs. Endothelial cell growth factor might further stimulate healing.10 Nakhostine et al.20 studied the effect of abrasion in the healing of a longitudinal full-thickness tear in the avascular inner half of the anterior part of the lateral meniscus in a sheep model. They found that that the distance from the periphery to the defect is too far for abrasion therapy to stimulate sufficient cellular ingrowth in this avascular region. Despite the results of the latter study, we abraded the borders of the tear in all cases, assuming this promotes a vascular reaction. Healing at the periphery will decrease the long-term incidence of arthritis in knees that undergo meniscal repair.5 Therefore, we consider any amount of healing of a repair at the periphery of the meniscus at the posterolateral corner as a successful repair, particularly in view of the alternative (i.e., subtotal meniscectomy). One of the patients had healing of zone 01 anterior to the popliteus fossa, but failed to coapt the 2 and 3 zone, which was resected at second-look arthroscopy. In another patient, the inferior part of the tear
failed to seal and was subsequently resected. However, the superior surface was intact throughout. It was felt that in both cases the meniscus would be able to transmit hoop stresses because of the intact peripheral rim. In all but the one patient who failed to coapt zone 2-3, three sutures were tied over the radial split. That patient underwent suturing with two stitches. Therefore, we advise the use three sutures to repair of a radial split in zone E.
CONCLUSIONS The ability of an exogenous fibrin clot to stimulate and support a reparative response in the avascular portion of the meniscus may represent a potential method of repair with good results. This technique probably is advantageous in the repair of a radial split of the lateral meniscus anterior to the popliteus fossa. We believe that tears in the avascular zone anterior to the popliteus fossa have a reasonable chance to heal with the use of this technique, when the only other option is total meniscectomy. It can be combined with vascular access channels to further increase healing. Enlarging the contact area is an important factor when meniscal repair is considered. In all our cases, at least the peripheral rim of the meniscus had healed. Hence, we consider all repairs successful in enlarging the area for force distribution in the knee. Awareness of the relative low healing potential of this zone and maximum enhancement of healing opportunities should aid in healing of a radial split at the avascular part of the lateral meniscus, anterior to the popliteus fossa. REFERENCES 1. Voloshin AS, Wosk J. Shock absorption of meniscectomized and painful knees: a comparative in vivo study. J Biomed Eng 1983;5:157-161. 2. Cox JS, Nye CE, Schaefer WW, et al. The degenerative effects of partial and total resection of the medial meniscus in dogs’ knees. Clin Orthop Rel Res 1975;109:178-183. 3. Newman AP, Daniels AU, Burks RT. Principles and decision making in meniscal surgery. Arthroscopy 1993;9:33-51. 4. Fairbank TJ. Knee joint changes after meniscectomy. J Bone Joint Surg Br 1948;30:664-670. 5. Rangger C, Klestil T, Gloetzer W, et al. Osteoarthritis after arthroscopic partial meniscectomy. Am J Sports Med 1995;23: 240-244. 6. DeHaven KE. Rationale for meniscus repair or excision. Clin Sports Med 1985;4:267-273. 7. Lynch MA, Henning CE, Glick KR, Jr. Knee joint surface changes. Long-term follow-up meniscus tear treatment in stable anterior cruciate ligament reconstructions. Clin Orthop Rel Res 1983;172:148-153. 8. DeHaven KE. Decision-making factors in the treatment of meniscus lesions. Clin Orthop Rel Res 1990;252:49-54.
MENISCAL REPAIR WITH FIBRIN CLOT 9. Arnoczky SP, Warren RF. Microvasculature of the human meniscus. Am J Sports Med 1982;10:90-95. 10. Hashimoto J, Kurosaka M, Yoshiya S, et al. Meniscal repair using fibrin sealant and endothelial cell growth factor. An experimental study in dogs. Am J Sports Med 1992;20: 537-541. 11. Zhang Z, Arnold JA, Williams T, et al. Repairs by trephination and suturing of longitudinal injuries in the avascular area of the meniscus in goats. Am J Sports Med 1995;23:35-41. 12. Arnoczky SP, Warren RF, Spivak JM. Meniscal repair using an exogenous fibrin clot. An experimental study in dogs. J Bone Joint Surg Am 1988;70:1209-1217. 13. van Trommel MF, Potter HG, Ernberg LA, et al. The utility of non-contrast MR imaging in the evaluation of meniscal repair: Comparison with conventional arthrography. Arthroscopy 1998; 14:2-8. 14. Lysholm J, Hamberg P, Gillquist J. The correlation between osteoarthrosis as seen on radiographs and on arthroscopy. Arthroscopy 1987;3:161-165.
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15. Cooper DE, Arnoczky SP, Warren RF. Arthroscopic meniscal repair. Clin Sports Med 1990;9:589-607. 16. Kimura M, Shirakura K, Hasegawa A, et al. Second look arthroscopy after meniscal repair. Factors affecting the healing rate. Clin Orthop Rel Res 1995;314:185-191. 17. Cannon WD Jr, Vittori JM. The incidence of healing in arthroscopic meniscal repairs in anterior cruciate ligamentreconstructed knees versus stable knees. Am J Sports Med 1992;20:176-181. 18. DeHaven KE, Lohrer WA, Lovelock JE. Long-term results of open meniscal repair. Am J Sports Med 1995;23:524-530. 19. Horibe S, Shino K, Nakata K, et al. Second-look arthroscopy after meniscal repair. Review of 132 menisci repaired by an arthroscopic inside-out technique. J Bone Joint Surg Br 1995;77:245-249. 20. Nakhostine M, Gershuni DH, Anderson R, et al. Effects of abrasion therapy on tears in the avascular region of sheep menisci. Arthroscopy 1990;6:280-287.
Summary: Peripheral lateral meniscal tears are amenable to arthroscopic meniscal repair. However, the posterolateral aspect of the lateral meniscus adjacent to the popliteus tendon is devoid of penetrating peripheral vessels and therefore difficult to heal. A complete radial split at this site is usually treated with total meniscectomy. We report five cases of a tear of the posterolateral aspect of the lateral meniscus anterior to the popliteus fossa. All patients had a radial split that extended to the popliteus tendon. In all cases, the repair was enhanced with a fibrin clot. Second-look arthroscopy showed that healing of the periphery occurred in all of the cases. All patients returned to their initial level of sports activity. Three of five patients were available for follow-up at an average of 71 months, and magnetic resonance imaging was performed at that time to assess the previously repaired meniscus. All menisci were fully healed and showed no further signs of degeneration. The ability of an exogenous fibrin clot to stimulate and support a reparative response in the avascular portion of the meniscus may represent a potential method of repair. Awareness of the relatively low healing potential of this zone and enhancement of healing opportunities should improve outcome. Key Words: Meniscal repair—Avascular zone—Lateral meniscus—Fibrin clot.
T
he intact meniscus is crucial for maintaining a multitude of normal joint functions, including shock absorption, joint lubrication, and force transmission across the knee joint, by increasing contact area and thereby decreasing contact stress on the articular cartilage.1-3 Meniscal pathology may result in degeneration of articular cartilage.2,4,5 This has been especially true in the case of total lateral meniscectomy in the young athletic patient. Preservation of meniscal tissue when possible, will result in a more optimized clinical outcome.6,7 The decision to repair the meniscus is multifactoFrom The Sports Medicine Service, The Hospital for Special Surgery, affıliated with the New York Hospital-Cornell University Medical College, New York, New York, U.S.A. Address correspondence and reprint requests to Michiel F. van Trommel, M.D., Onze Lieve Vrouwe Gasthuis, Department of Orthopaedics, 1e Oosterparkstraat 279, 1091 HA Amsterdam, The Netherlands. r 1998 by the Arthroscopy Association of North America 0749-8063/98/1404-1632$3.00/0
360
rial.8 Peripheral lateral meniscal tears are amenable to arthroscopic meniscal repair. However, the posterolateral aspect of the lateral meniscus adjacent to the popliteus tendon is devoid of penetrating peripheral vessels (Fig 1),3,9 which would make meniscal repair less appealing. Partial radial tears are easily managed with subtotal meniscectomy but complete radial tears into the popliteus sleeve necessitates total meniscectomy. This report deals with the latter situation (Fig 2A and B).3 Meniscal suture alone may stabilize the tear and stimulate cell proliferation for healing, but it appears to be significantly restricted without an adequate blood supply (Fig 2C).8 Several techniques are described to enhance meniscal healing in avascular zones. These include the use of a fibrin clot, trephination, and growth factors.10-12 Younger patients and athletes are at greater risk for arthritic changes with partial or total meniscectomy.7 In these cases therefore, repair is indicated.
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 14, No 4 (May-June), 1998: pp 360–365
MENISCAL REPAIR WITH FIBRIN CLOT
Due to copyright restrictions, this figure is not available online. Please see the print version.
FIGURE 1. Schematic drawing of the vascularity of the lateral meniscus. The zone anterior to the popliteus fossa is devoid of penetrating vessels. (Reprinted with permission.3 )
We report five cases of a tear of the posterolateral aspect of the lateral meniscus anterior to the popliteus fossa. All patients had a complete radial split that extended to the popliteus tendon. In all cases, the repair was enhanced with a fibrin clot and all had second-look arthroscopy. Three patients were contacted for long-term follow-up (average 71 months) including magnetic resonance imaging (MRI) of the repair site. MATERIALS AND METHODS Technique Repair of the posterolateral aspect of the lateral meniscus anterior to the popliteus fossa was preceded by abrasion of the tear surfaces. Multiple horizontal sutures (0-PDS) were positioned across the tear in an outside-to-inside fashion. The inner sutures were placed first, followed by more peripheral sutures. Before tying the knots, an exogenous fibrin clot was placed in the seam of the tear. One to 2 mL of clot was sufficient to fill the defect. The postoperative protocol constituted of immobilization and nonweightbearing for 3 weeks. The motion was then gradually expanded over the next few weeks with physical therapy. Squatting beyond 90° and
361
running activities were not allowed for 4 months. During this period, the knee was protected with a derotation brace. After 4 to 5 months, sporting activities were resumed. Second-look arthroscopy was performed in all patients at 4 months (range, 3 to 6 months) after the index operation to assess the repaired meniscus. MRI Technique MRI was performed on a 1.5 Tesla unit (Signa; General Electric Medical Systems, Milwaukee, WI), using a send-receive extremity coil. Pulse sequences included coronal spin echo sequences (repetition time TR/echo time msec TE (Ef) 4,000/38; field of view 13 cm; slice thickness 3.5 mm with no interslice gap; matrix 512 ⫻ 256 at two excitations. Sagittal fast spin echo sequences were obtained with TR/TE (msec) 4,000/36; field of view 13 to 18 cm; matrix 256 ⫻ 224 at two excitations, slice thickness 4 mm with no interslice gap. The latter images were obtained with frequency-selective fat suppression (Chemsat; General Electric Medical Systems). High-resolution sagittal images were obtained to evaluate articular cartilage and intrameniscal morphology utilizing TR 4,000/TE 30 msec (Ef); field of view 16 cm; slice thickness 3.5 mm with no interslice gap; matrix 512 ⫻ 256 or 512 ⫻ 384 at two excitations. In the presence of interference screws from concomitant anterior cruciate reconstruction, tailored RF (General Electric Medical Systems) was additionally used to diminish interecho spacing. Meniscal morphology was judged based on the intact appearance of the meniscus, and meniscus was deemed to be healed if there was no fluid imbibition into the substance of the fibrocartilage, as previously reported.13 Fragmentation when present was noted, and the capsular attachments were also evaluated. Note was made if there was concomitant partial meniscectomy. In addition, fast spin echo sequences were used to evaluate the adjacent articular cartilage using a modified Outerbridge classification.14 Clinical Cases Five patients with an average age of 20 years (range, 18 to 22 years) were included. All patients had a history of pain and occasional swelling of the knee following a traumatic sporting injury. The duration of the symptoms averaged 25 months (range, 4 to 79 months). At surgery in all cases, a complete radial split at the level of the popliteus fossa extending from the periphery to the central part of the meniscus was found (zone E, area 0123 according to Cooper,15 Fig 3). A repair was performed with 2 or 3 PDS sutures tied in an outside-to-inside fashion over a fibrin clot (see
362
M. F. VAN TROMMEL ET AL.
FIGURE 2. (A) Schematic drawing of a lateral meniscus. A limited tear in zone 3 can be addressed with a partial meniscectomy (B) A radial split of zone E 0123, i.e., extending from the central part of the lateral meniscus to the popliteus fossa, cannot be treated with a partial meniscectomy because this would separate the posterior and anterior horn. (C) Suturing of the lateral meniscus over a fibrin clot (not drawn) preserves meniscal integrity.
technique session for details). One patient had a torn anterior cruciate ligament (ACL) that was addressed at the same procedure with a bone–patellar tendon–bone graft. In this same patient, trephination of the meniscus
was done to both decompress a meniscal cyst, which was associated with the tear and encourage vascularization. This patient had been symptomatic for 7 months. After the second-look arthroscopy three of five pa-
MENISCAL REPAIR WITH FIBRIN CLOT
363
Due to copyright restrictions, this figure is not available online. Please see the print version.
FIGURE 3. Different meniscal zones according to Cooper et al.15 P, popliteus tendon. (Reprinted with permission.15 )
tients were followed clinically and radiologically by means of MRI to assess meniscal integrity13 at the repair site with an average follow-up of 71 months (range, 66 to 81 months) (Table 1). Two patients were lost to follow-up. RESULTS All patients had a routine second-look arthroscopy 4 months after the initial treatment (range, 3 to 5 months). At second-look arthroscopy, excellent healing had occurred in 3 of 5 patients. Of these, in two cases a small area in zone 3 appeared minimally deficient, probably due to a tissue mismatch during the repair, and the residual inner rim of zone 3 was trimmed. In the fourth patient, the inferior part of the tear failed to seal and it was subsequently resected. The superior surface of the lateral meniscus, however, was intact throughout. The fifth patient, who also had an ACL reconstruction and a cyst decompression at the initial procedure, continued to have a fair amount of discomfort before the second-look arthroscopy. The pain was located at the region where the cyst was decompressed and where the sutures for the meniscal repair were placed. At second-look arthroscopy, the meniscus had healed in zone 01 anterior to the
FIGURE 4. Coronal fast spin echo MRI 67 month postoperative indicating full healing (curved arrow) without residual signal hyperintensity. Zone 3 has been trimmed at second-look arthroscopy (straight arrow).
popliteus fossa, but failed to coapt at the 2 and 3 zone, which was resected. At follow-up, he was completely asymptomatic. All patients were able to return to their initial level of sports. Two patients were lost to follow-up after the secondlook arthroscopy. Three patients agreed to have MRI and a clinical re-evaluation of their knee, despite the fact that they were clinically asymptomatic. MRI showed a fully healed meniscus at the repair sites in all cases with no further disruption of the debrided area that previously was addressed at second-look arthroscopy in two of the patients (Fig 4).
TABLE 1. Patient Data Case
Age (y)
Sport
1 2 3 4 5
20 19 18 18 22
Football Running Basketball Basketball Hockey
Time to Symptomatic at Surgery (mo) Second-Look Arthroscopy 79 31 6 4 7
No No No Yes Yes
Results of Second-Look Arthroscopy Inferior part resected Healed Healed Healed Zone 0-1 healed, 2-3 resected
Follow-up Symptomatic Time (mo) at Follow-up N/A N/A 67 81 66
N/A N/A No No No
Results of MRI N/A N/A Healed Healed 0-1 healed
364
M. F. VAN TROMMEL ET AL. DISCUSSION
Many studies have shown healing rates for meniscal repair ranging from 50% to 89%.16-19 To our knowledge, there are no studies determining the healing rate at the avascular zone anterior to the popliteus fossa. Factors to consider when assessing healing rates include location and type of the tear, technique of repair, and stability of the knee. The posterolateral area of the lateral meniscus, zone E, has been noted to be devoid of vasculature.9 Kimura et al.16 found 50% no healing of avascular meniscal zones at second-look arthroscopy. However, their series also included repairs at the central zones (i.e., 2 and 3) of both the medial and lateral meniscus. Several techniques for enhancement of healing have been described. Arnoczky et al.12 documented in an animal model that defects filled with fibrin clot heal through a proliferation of fibrous connective tissue that eventually modulates into fibrocartilaginous tissue. The fibrin clot appears to act as a chemotactic and mitogenic stimulus for reparative cells and provides a scaffolding for the reparative process. A fibrin clot was used in all our cases. In the case of concomitant ACL reconstruction, postoperative hemarthrosis may provide serum proteins, growth factors, and a fibrinous framework to the tear and promote healing. This is analogous to the addition of a fibrin clot to the tear at the time of the repair, and therefore insertion of a fibrin clot may not be necessary. Fibrin clot deposition along with vascular access channels are advances that potentially increase healing rates of meniscal repairs. Endothelial cell growth factor might further stimulate healing.10 Nakhostine et al.20 studied the effect of abrasion in the healing of a longitudinal full-thickness tear in the avascular inner half of the anterior part of the lateral meniscus in a sheep model. They found that that the distance from the periphery to the defect is too far for abrasion therapy to stimulate sufficient cellular ingrowth in this avascular region. Despite the results of the latter study, we abraded the borders of the tear in all cases, assuming this promotes a vascular reaction. Healing at the periphery will decrease the long-term incidence of arthritis in knees that undergo meniscal repair.5 Therefore, we consider any amount of healing of a repair at the periphery of the meniscus at the posterolateral corner as a successful repair, particularly in view of the alternative (i.e., subtotal meniscectomy). One of the patients had healing of zone 01 anterior to the popliteus fossa, but failed to coapt the 2 and 3 zone, which was resected at second-look arthroscopy. In another patient, the inferior part of the tear
failed to seal and was subsequently resected. However, the superior surface was intact throughout. It was felt that in both cases the meniscus would be able to transmit hoop stresses because of the intact peripheral rim. In all but the one patient who failed to coapt zone 2-3, three sutures were tied over the radial split. That patient underwent suturing with two stitches. Therefore, we advise the use three sutures to repair of a radial split in zone E.
CONCLUSIONS The ability of an exogenous fibrin clot to stimulate and support a reparative response in the avascular portion of the meniscus may represent a potential method of repair with good results. This technique probably is advantageous in the repair of a radial split of the lateral meniscus anterior to the popliteus fossa. We believe that tears in the avascular zone anterior to the popliteus fossa have a reasonable chance to heal with the use of this technique, when the only other option is total meniscectomy. It can be combined with vascular access channels to further increase healing. Enlarging the contact area is an important factor when meniscal repair is considered. In all our cases, at least the peripheral rim of the meniscus had healed. Hence, we consider all repairs successful in enlarging the area for force distribution in the knee. Awareness of the relative low healing potential of this zone and maximum enhancement of healing opportunities should aid in healing of a radial split at the avascular part of the lateral meniscus, anterior to the popliteus fossa. REFERENCES 1. Voloshin AS, Wosk J. Shock absorption of meniscectomized and painful knees: a comparative in vivo study. J Biomed Eng 1983;5:157-161. 2. Cox JS, Nye CE, Schaefer WW, et al. The degenerative effects of partial and total resection of the medial meniscus in dogs’ knees. Clin Orthop Rel Res 1975;109:178-183. 3. Newman AP, Daniels AU, Burks RT. Principles and decision making in meniscal surgery. Arthroscopy 1993;9:33-51. 4. Fairbank TJ. Knee joint changes after meniscectomy. J Bone Joint Surg Br 1948;30:664-670. 5. Rangger C, Klestil T, Gloetzer W, et al. Osteoarthritis after arthroscopic partial meniscectomy. Am J Sports Med 1995;23: 240-244. 6. DeHaven KE. Rationale for meniscus repair or excision. Clin Sports Med 1985;4:267-273. 7. Lynch MA, Henning CE, Glick KR, Jr. Knee joint surface changes. Long-term follow-up meniscus tear treatment in stable anterior cruciate ligament reconstructions. Clin Orthop Rel Res 1983;172:148-153. 8. DeHaven KE. Decision-making factors in the treatment of meniscus lesions. Clin Orthop Rel Res 1990;252:49-54.
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