MENISCUS

Augmentation

Augmentation techniques are useful during attempts to salvage meniscal tears in the avascular zone. They are also useful in the more chronic tears and whilst repairing tears in stable knees without concomitant ligament reconstruction.

The techniques available to augment healing of meniscal tears are -

1. Meniscal rasping
2. Synovial abrasion
3. Synovial graft
4. Fibrin clot
5. Meniscal trephining
6. Microfracture
7. Radiofrequency stimulation

Meniscal Rasping

Rasping the meniscal edges rather than the primeniscal synovium has also been shown to augment meniscal heling through the expression of cytokines.

Uchio showed results of meniscal rasping without suturing in a retrospective study. Forty-eight meniscal tears treated arthroscopically with the meniscal rasping technique were evaluated by second-look arthroscopy. The interval between the injury and the time of surgery ranged from 3 weeks to 13 years. There were 35 lateral and 13 medial meniscal tears associated with 44 anterior cruciate ligament injuries; 28 of the menisci had a full-thickness longitudinal tear and the other 20 had a partial-thickness tear. The length of the tears ranged from 10 to 33 mm (mean, 14.4 mm). The distance from the capsule to the tear ranged from 1 to 9 mm (mean, 5.0 mm). There was 71% complete healing at second look arthroscopy. The distance of the tear site from the capsule, length and the stability of the tear affect healing potential.

Ochi M, Uchio Y, Okuda K, Shu N, Yamaguchi H, Sakai Y. Expression of cytokines after meniscal rasping to promote meniscal healing. Arthroscopy. 2001 Sep;17(7):724-31

Uchio Y, Ochi M, Adachi N, Kawasaki K, Iwasa J. Results of rasping of meniscal tears with and without anterior cruciate ligament injury as evaluated by second-look arthroscopy. Arthroscopy. 2003 May-Jun;19(5):463-9

Okuda K, Ochi M, Shu N, Uchio Y. Meniscal rasping for repair of meniscal tear in the avascular zone. Arthroscopy. 1999 Apr;15(3):281-6.

Synovial Abrasion

This technique can be performed using a curved arthroscopic rasp or using a arthroscopic shaver (synovator). Access to the synovium in the posterior third can be achieved by displacing the meniscus fragment back towards the notch.

Talley reported results from 44 partial stable meniscal tears that were treated with parameniscal synovial abrasion at the time of anterior cruciate ligament reconstruction. Meniscal repair was not performed. Four failures occurred in the medial meniscus (21% of total MM tears) and 1 failure occurred in the lateral meniscus (4% of total LM tears). The median time to failure was 12 months.

Nachostine performed an animal study for avascular zone tears where the tears. They concluded that the distance from the periphery to the defect is too far for abrasion therapy to stimulate sufficient cellular ingrowth to facilitate repair of tears in the avascular region of the meniscus.

Talley MC, Grana WA. Treatment of partial meniscal tears identified during anterior cruciate ligament reconstruction with limited synovial abrasion. Arthroscopy. 2000 Jan-Feb;16(1):6-10.

McAndrews PT, Arnoczky SP. Meniscal repair enhancement techniques. Clin Sports Med. 1996 Jul;15(3):499-510.

Nakhostine M, Gershuni DH, Anderson R, Danzig LA, Weiner GM. Effects of abrasion therapy on tears in the avascular region of sheep menisci. Arthroscopy. 1990;6(4):280-7.

Synovial graft

Kimura performed a vascularized synovial pedicle flap to the suture site 7 tears in avascularized areas and all of them showed healing on second look arthroscopy. They performed repeat arthroscopy on 46 of 137 meniscal repairs. In patients with tears in avascularized areas, the conventional meniscal repairs showed a lower healing rate than did the repairs with a synovial pedicle transplantation or an anterior cruciate ligament reconstruction (p < 0.005).

In an animal study, Jijsuiki performed meniscal repairs in the avascular zone on 34 rabbit knees. There were17 in the study group and 17 in the control group. In the study group, an interpositional free synovial autograft was sewn into the tear with a single horizontal suture. In the control group, the tear was repaired without synovium in the same manner. In the study group, the lesion completely healed by 4 weeks, except for one. The menisci in the control group never completely healed, particularly at the deeper levels of the lesion. Ochi showed similar beneficial effect of free synovial graft.

Jitsuiki J, Ochi M, Ikuta Y. Meniscal repair enhanced by an interpositional free synovial autograft: an experimental study in rabbits. Arthroscopy. 1994 Dec;10(6):659-66.

Kimura M, Shirakura K, Hasegawa A, Kobuna Y, Niijima M. Second look arthroscopy after meniscal repair. Factors affecting the healing rate. Clin Orthop Relat Res. 1995 May;(314):185-91.

Ochi M, Mochizuki Y, Deie M, Ikuta Y. Augmented meniscal healing with free synovial autografts: an organ culture model. Arch Orthop Trauma Surg. 1996;115(3-4):123-6.

Fibrin Clot

Fibrin clot acts as a chemotactic and mitogenic stimulus for reparative cells and provides a scaffolding for the reparative process. The clot contains platelet-derived growth factor and fibronectin, which are chemotactic. They appear to stimulate local cell activity within the meniscus and to attract synovial cells.

Arnoczky (1988) demonstrated that defects created in the avascular zone of menisci when filled with a fibrin clot healed through a proliferation of fibrous connective tissue that eventually modulated into fibrocartilaginous tissue. Control defects remained empty. The reparative tissue was morphologically similar to the reparative tissue that was observed in the vascular area of the meniscus.

Technique of fibrin clot preparation

Preparation of the clot in this setting is important; the clot should contain as little serum and red cells as possible. Generally, 50-60 ml of blood is spun in a glass container. The clot is removed from the glass stirring rod and inserted in a tube before placement in the tear after the ACL reconstruction. Tibial fixation of the graft is performed after placing the clot. If desired, the clot can be tied in place with a PDS suture.

Sethi described a insitu technique of creating a fibrin clot. The synovium directly above the tear site is abraded with a shaver, rasp, or small intra-articular banana blade. Next, the water inflow cannula is closed, and the outflow cannula is opened to vacuum suctioning, allowing collapse of the distended joint. Under these circumstances, negative intra-articular pressure is produced in the knee joint. This condition is maintained for a period of 1 to 2 minutes and induces bleeding from the abraded synovial site. The knee in a dependent position causes the blood to run down the synovial wall and into the meniscal cleft, pooling there and forming a clot adherent to the edges of the separated meniscal tear. This procedure has been found to be a simple and minimally invasive mechanism for clot placement. The exposed collagen of the meniscal tear provides an ideal surface for a relatively tenacious clot attachment. It provides the healing factors reported to induce successful meniscal healing.

Arnoczky SP, Warren RF, Spivak JM Meniscal repair using an exogenous fibrin clot. An experimental study in dogs. J Bone Joint Surg Am.1988 Sep;70(8):1209-17.

Sethi PM, Cooper A, Jokl P. Technical tips in orthopaedics: meniscal repair with use of an in situ fibrin clot. Arthroscopy. 2003 May-Jun;19(5):E44.

Port J, Simon TM, Jackson DW. Preparation of an exogenous fibrin clot. Arthroscopy. 1995 Jun;11(3):332-7.

O'Meara PM. Surgical techniques for arthroscopic meniscal repair. Orthop Rev. 1993 Jul;22(7):781-90. Review.

van Trommel MF, Simonian PT, Potter HG, Wickiewicz TL. Arthroscopic meniscal repair with fibrin clot of complete radial tears of the lateral meniscus in the avascular zone. Arthroscopy. 1998 May-Jun;14(4):360-5.

McAndrews PT, Arnoczky SP. Meniscal repair enhancement techniques. Clin Sports Med. 1996 Jul;15(3):499-510.

Trephination

Trephination is a technique to create vascular access channels by removal of a core of tissue from the periphery of the meniscus to the tear, thus connecting a lesion in the avascular portion of the meniscus to the peripheral blood supply. The technique is performed through the arthroscopic prtals using a spinal needle. The channels are equally spaced with controlled depth of insertion, going through the rim portion of the meniscus.

Zang showed in an animal study the proliferation of fibrochondrocyte in meniscal tears after trephining. In a further clinical study, thirty-six patients with meniscal tears underwent arthroscopic trephination plus suturing (group TS) and 28 patients had suturing alone (group S). The follow-up was 25 to 78 months. Two symptomatic retears have occurred in group TS and 7 symptomatic retears in group S. The symptomatic retear rate of group TS was significantly smaller than group S (P < .01). Trephination appeared to reduce clinical failure rate.

Shelbourne reported good results in 332 lateral meniscus tears treated with abrasion or trephining but not repaired at the time of ACL reconstruction. Fox showed similar results with trephination and conservative treatment of meniscal tears.

Biedert examined the effect of four different methods for treating intrasubstance meniscal lesions. Forty patients with an isolated and symptomatic painful horizontal grade 2 meniscal lesion on the medial side (documented with MRI) were included. Created vascular access channels appeared to give good success rates.

Cook and Fox used a bioabsorbable vascular conduit for avascular meniscal tears. Based on histologic assessment, the conduit was associated with complete (n = 4) or partial (n = 5) healing in all avascular defects at 12 and 24 weeks after surgery in their study. No healing was seen in defects treated by trephination and repair. The load to failure of the conduit treated menisci were also significantly better suggesting better repair tissue.

Zhang Z, Arnold JA. Trephination and suturing of avascular meniscal tears: a clinical study of the trephination procedure. Arthroscopy. 1996 Dec;12(6):726-31.

Fox JM, Rintz KG, Ferkel RD. Trephination of incomplete meniscal tears. Arthroscopy. 1993;9(4):451-5

Zhang ZN, Tu KY, Xu YK, Zhang WM, Liu ZT, Ou SH. Treatment of longitudinal injuries in avascular area of meniscus in dogs by trephination. Arthroscopy. 1988;4(3):151-9

Shelbourne KD, Heinrich J. The long-term evaluation of lateral meniscus tears left in situ at the time of anterior cruciate ligament reconstruction. Arthroscopy. 2004 Apr;20(4):346-51.

Biedert RM. Treatment of intrasubstance meniscal lesions: a randomized prospective study of four different methods. Knee Surg Sports Traumatol Arthrosc. 2000;8(2):104-8.

Cook JL, Fox DB. A novel bioabsorbable conduit augments healing of avascular meniscal tears in a dog model. Am J Sports Med. 2007 Nov;35(11):1877-87. Epub 2007 Aug 16.

Microfracture

Autologous Bone marrow stem cells can improve meniscal wound healing. Whether this improvement occurs through BMSC differentiation into cells operational in the repair process, the release of certain mediator or other unknown mechanisms mandates further investigations.

Microfracture is a commonly performed procedure and can help bring in these stem cells in to the meniscal defect. This is performed in the lateral wall of the notch.

Freedman KB, Nho SJ, Cole BJ. Marrow stimulating technique to augment meniscus repair. Arthroscopy. 2003 Sep;19(7):794-8.

Radiofrequency

Radiofrequency energy may induce fibroblast proliferation for meniscal repair. Monopolar RFE denatures and fuses collagen and also produces fibrochondrocyte death to a limited area. There is then fibroblast cell proliferation at 2 weeks. The acellular area is repopulated by 12 weeks(Hatayama).

Themal welding has been experimentally tried for meniscal repairs. The internal structure of the nuclei of the cells are preserved at 63 degrees C, whereas cells were denatured inside the nuclei in the 69 degrees C. They exhibited necrosis, making cell regeneration difficult. It seems feasible that thermal welding at 63 degrees C can repair tears in the human meniscal white zone. Use of laser alone has been shown to be insufficient to repair unstable meniscus tears(Vangsness).

Laser-assisted fibrin clot soldering may allow the opposing edges of a meniscal tear to be held together with a biologic scaffold, possibly inducing reparative cell migration and proliferation. After irradiation with argon ion laser energy, the tensile strength of the laser-assisted fibrin clot-bonded menisci increased 40-fold over that of nonirradiated fibrin clot-bonded menisci.

Imakiire N, Kotani A, Ishii Y. Experimental study on thermal welding for the knee meniscal white zone. J Orthop Sci. 2003;8(5):683-92.

Vangsness CT Jr, Akl Y, Marshall GJ, Subin W, Smith CF. The effects of the neodymium laser on meniscal repair in the avascular zone of the meniscus. Arthroscopy. 1994 Apr;10(2):201-5.

Forman SK, Oz MC, Lontz JF, et al: Laser-assisted fibrin clot soldering of human menisci. Clin Orthop 310:37-41, 1995

Hatayama K, Higuchi H, Kimura M et al. Histologic changes after meniscal repair using radiofrequency energy in rabbits. Arthroscopy. 2007 Mar;23(3):299-304.

Lopez MJ, DeTemple LA, Lu Y, Markel MD. The effects of monopolar radiofrequency energy on intact and lacerated ovine menisci. Arthroscopy. 2001 Jul;17(6):613-9.

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