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Popliteal cystoscopic excisional debridement and removal of capsular fold of valvular mechanism of large recurrent popliteal cyst
Popliteal Cystoscopic Excisional Debridement and Removal of Capsular Fold of Valvular Mechanism of Large Recurrent Popliteal Cyst SangHun Ko, M.D., Ph.D., and JinHwan Ahn, M.D.
Purpose: The purpose of this study was to evaluate the effectiveness of cystoscopic excisional debridement and removal of unilateral flow of the capsular fold of valvular mechanism in the posteromedial corner of the recurrent popliteal cyst. Type of Study: Retrospective review. Methods: From March 1998 to May 2000, we treated 14 cases of popliteal cyst by cystoscopic excisional debridement. The cysts were relatively large cysts, about 5 cm in diameter on sonography. Conservative treatment for about 1 year, with about 3 aspirations failed. The mean follow-up duration was 29.7 (24 to 36) months. We used Rauschning and Lindgren criteria for evaluations. We estimated surgical time. Patients underwent sonography 6 months and 1 year after surgery. Pain, range of motion, and recurrence were checked 1 year after surgery. Results: The average surgical time was 45 (31 to 58) minutes. The time to pain elimination and full range of motion was 1 or 2 days after surgery. No recurrence was noted in any patients. At the last follow-up, patients reported no discomfort or pain, and all had free range of motion. Preoperatively, Rauschning and Lindgren criteria were grade 0 in 0 cases; grade 1 in 3 cases; grade 2 in 10 cases; and grade 3 in 1 case. At 2 weeks after surgery, criteria were grade 0 in 13 cases and grade 1 in 1 case; at final follow-up evaluation, all were grade 0. Hematoma occurred in 1 case. However, in cases lost to follow-up and in short-term follow-up cases, technical errors occurred: not entering within the cyst in 2 cases, extravasion in 1 case, and recurrence in 1 case. Conclusions: A popliteal cystoscopic excisional debridement by motorized shaver and removal of the capsular fold of the valvular mechanism is an effective alternative to the open technique of treating popliteal cysts. Key Words: Recurrent popliteal cyst—Arthroscopic direct shaving cystectomy.
T
he preferred treatments for popliteal cysts have been conservative treatment or open resection. Many methods of surgical resection have been suggested, but the recurrence is high after simple resec-
From the Department of Orthopedic Surgery, Ulsan University College of Medicine, Ulsan (S.H.K.); and Samsung Medical Center School of Medicine, Sungkyunkwan University, Seoul (J.H.A.), South Korea. Portions of this article were presented at the meeting of the International Society of Arthroscopy, Knee Surgery, and Sports Medicine, Montreux, Switzerland, March 2001. Address correspondence and reprint requests to Sang Hun Ko, M.D., Ph.D., 290-3, JeonHa-Dong, Dong-Gu, Ulsan MetropolitanCity 682-714, South Korea. E-mail: [email protected] © 2004 by the Arthroscopy Association of North America 0749-8063/04/2001-3477$30.00/0 doi:10.1016/j.arthro.2003.10.017
tion.1,2 We noted that the popliteal cyst has intraarticular pathology,1,3 and Sansone and De Ponti4 suggested changing treatment strategies. As arthroscopic technique improves, the indication of arthroscopy is widening and associated intra-articular pathology can be effectively treated using arthroscopy.4-7 We tried arthroscopic direct shaving cystectomy of the thickened cyst wall in the recurrent popliteal cyst 3 times previously after the failure of long-term conservative treatment. We removed the one-way flow of the valvular mechanism after enlargement and removed the capsular fold in large cysts (about 5 cm). The purpose of this study was to evaluate the effectiveness of direct shaving cystectomy and removal of unilateral flow of the capsular fold of valvular mechanism in the posteromedial corner of the recurrent popliteal cyst.
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 20, No 1 (January), 2004: pp 37-44
37
38
S. H. KO AND J. H. AHN TABLE 1. Operation Time, Pain Duration, Interval of Full ROM, and Interval of Last Follow-up Case Age/Sex
FIGURE 1.
Time to absence of pain.
1 2 3 4 5 6 7 8 9 10 11 12 13 14
39/F 45/F 52/M 47/F 53/M 49/F 50/F 44/M 43/F 52/M 54/F 56/F 62/M 51/M
Operation Time 37 46 53 37 44 49 47 42 58 31 38 54 49 39
min min min min min min min min min min min min min min
Pain-Free Duration 24 24 24 48 24 24 24 24 24 24 24 24 72 24
hr hr hr hr hr hr hr hr hr hr hr hr hr hr
Interval of Last Full ROM Follow-up 48 24 48 48 48 48 48 24 24 48 24 48 48 48
hr hr hr hr hr hr hr hr hr hr hr hr hr hr
30 27 28 26 32 29 31 24 27 30 25 36 34 35
mo mo mo mo mo mo mo mo mo mo mo mo mo mo
METHODS From March 1998 to May 2000, 14 of 22 cases of popliteal cyst were treated arthroscopically. Patients included 6 men and 8 women. The control group was composed of the other 8 patients with presumed symptomatic popliteal cysts for which conservative management failed. The control group was treated with open surgery, but included 6 cases of joint pain lasting more than 2 days and motion limitation. Cysts recurred in 2 cases. Average patient age was 48 years (range, 39 to 62 years). We evaluated the surgical time, associated pathology, time to pain elimination (Fig 1), and time to full range of motion (ROM) (Fig 2). We used Rauschning and Lindgren knee scores for evaluation. The average follow-up time was 29.7 months (range, 24 to 36 months) (Table 1). Sonography was performed (Fig 3) before and after surgery. Recurrence
FIGURE 2.
Time to full range of motion.
was evaluated 6 and 12 months postoperatively (Fig 4). Preoperative magnetic resonance imaging was performed in 2 cases. The criteria for treatment included recurrent popliteal cysts with swelling, pain, limitation of motion, and nerve compression signs in the knee joint. All patients had undergone failed conservative treatment for approximately 1 year, and other systemic conditions were ruled out. The patients treated arthroscopically were those with relatively larger cysts, approximately 5 cm in diameter, evaluated by sonogram, for whom conservative treatment for 1 year with more than 3 aspirations failed. The cysts ballooned easily with injected normal saline. The reason these cases were selected
FIGURE 3. Sonographic findings show a large popliteal cyst in a 58-year-old woman.
TREATMENT OF A LARGE RECURRENT POPLITEAL CYST
FIGURE 4. rence.
39
One year after surgery, the sonogram shows no recurFIGURE 6. shaver.
The shaving of the outer cyst wall using the motorized
for arthroscopy is that we could expect well-developed thickened capsular walls and could easily introduce the shaver within the intracystic wall using arthroscopic instruments. The surgical method included using a marking pen and expanding the cyst with 20 mL of normal saline after verified aspiration of the yellowish cystic fluid. An 18-gauge needle was used with the patient in the lateral decubitus position under general or spinal anesthesia. In the lower pole of the ballooned cyst, the skin was incised about 3 mm with a No. 11 blade, and we introduced a blunt obturator and sheath. The arthroscope was inserted within the cystic wall. In the last 4 cases, we introduced subcutoscopy dissection by
inserted mosquette. We easily found the outer cyst wall (Fig 5). Diagnostic arthroscopy was performed within the intracyst wall. We inserted a motorized shaver on the contralateral side and performed direct shaving of the cyst wall with a suctioned motorized shaver (Figs 6 and 7). The tip of the shaver was pointed toward the inner side to avoid injuring the neurovascular structure, tendon, and muscle. We tried to avoid a lateral wall proximal to the neurovascular structure. Recurrent cysts have thickened, tortuous, and pedunculated roots. We tried to resect the roots completely using an arthroscopic scissor punch to avoid surrounding tissue (Figs 8 and 9). The hemovac suc-
FIGURE 5. The outer capsule of the recurrent popliteal cyst. We introduced the arthroscope subcutaneously in 4 cases.
FIGURE 7. The intracyst wall: the inner wall is shaved by the motorized shaver.
40
S. H. KO AND J. H. AHN
FIGURE 8. The punching of the thickened and tortuous roots using a meniscectomy punch.
FIGURE 10.
tion drain was inserted, and patient position was changed to supine. Diagnostic arthroscopy was performed using routine anterolateral, anteromedial, and superolateral portals. The posteromedial portal was used to visualize the posteromedial corner of the joint. After full examination of intra-articular joint pathology, we performed simple irrigation and simple meniscal shaving. An arthroscope was introduced to the posteromedial corner to verify a connecting hole to the cyst (Fig 10). If the fold connected to the cyst, we removed and resected the capsular fold completely and enlarged the valvular mechanism that was under the capsular fold (Fig 11). We cautiously introduced a shaver to the
portal that was not toward the medial side near the vascular tissue, and enlarged the capsular hole approximately 5 mm. If fibrous membranes, bands, and meniscal flaps are found within the cystic hole, we completely shaved and removed the material. If needed, we injected hyaluronic acid to joints with severe arthritis. We sometimes used triamcinolon injection for postoperative pain relief, and bupibarcaine 40 mL was also injected within the joint and cyst excision site. The hemovac suction drain was inserted in the joint, skin suture was performed, and a compressed elastic bandage was used.
FIGURE 9. The semimembraneous tendon after shaving of the popliteal cyst.
Visualization of the posteromedial connecting hole.
FIGURE 11. In the posteromedial corner of the knee joint, the valvular mechanism of the capsular fold is enlarged using a mosquito clamp and shaved.
TREATMENT OF A LARGE RECURRENT POPLITEAL CYST TABLE 2. Intra-articular Associated Lesion (n ⫽ 14) Associated Pathology
No. of Cases (%)
Degenerative change Medial meniscus tear Lateral meniscus tear Synovitis and synovial hypertrophy Chondromalacia and chondral defect Plica syndrome
10 (72%) 11 (79%) 3 (21%) 5 (36%) 4 (28%) 5 (36%)
RESULTS From March 1998 to May 2000, we performed surgery in symptomatic patients. Arthroscopic direct shaving cystectomy was performed in 14 of 22 cases. The surgical time from skin incision to suture of the arthroscopic portal averaged 45 minutes (31 to 58 minutes). The time to pain elimination and full ROM was 1 or 2 days after surgery (Table 1). The associated findings were degenerative cartilage damage in 10 cases (72%), medial meniscus tear in 11 cases (79%), lateral meniscal tear in 3 cases (21%), plica syndrome in 5 cases (36%), chondromalacia and cartilage defect in 4 cases (28%), and synovitis and synovial hypertrophy in 5 cases (36%) (Table 2). The knee joint showed full ROM in all cases by 1 year after surgery, and at final follow-up evaluation, no pain and no gait disturbances were seen. Complications included hematoma formation in 1 case, but this resolved after compression and rest. Functional evaluation was performed using Rauschning and Lindgren8 criteria (Fig 12). In the clinical evaluation of the results, we also followed guidelines proposed by Rauschning and Lindgren.2 The parameters considered were the subjective symptomatogy related to the presence of the popliteal cyst, pain and a posterior sense of tension in the popliteal fossa, and
FIGURE 12. The results of evaluation using Rauschning and Lindgren criteria.
41
TABLE 3. Clinical Evaluation of Results of Surgery According to Criteria of Rauschning and Lindgren Criteria Grade Grade Grade Grade
0 1 2 3
Before Surgery (no.)
2 Weeks After Surgery (no.)
After 1 year
Last Follow-up
0 3 10 1
13 1 0 0
14 0 0 0
14 0 0 0
the clinical importance of posterior swelling or reduction of ROM. All patients were evaluated by the following scale4: Grade 0: absence of swelling and pain, no limitation of range of motion. Grade 1: light swelling or a sense of posterior tension after intense activity, minimal limitation of ROM. Grade 2: swelling and pain after normal activity, ROM limitation less than 20°. Grade 3: swelling and pain even when resting, ROM limitation more than 20°. The grade at final follow-up evaluation was grade 0 in all cases (Table 3). In all cases, sonography was performed 6 and 12 months after surgery. No recurrence was found. Pain was reported for longer than 72 hours in 4 cases. One case developed mild hematoma at the site of the excised cyst, but this was improved with compression and rest, and popliteal pain lasted about 72 hours. Marked popliteal hematoma formation was reported in a case at a nearby college. However, because this case was not ours, it was excluded in this study. Two cases showed inadequate shaving because of a technical error. In one case, the arthroscopic trochar was not introduced within the cyst wall initially, and we opened the cyst and performed excision by scalpel. In another case, arthroscopic shaving of the cyst was performed aggressively, and the patient felt pain at the popliteal site. This patient was discharged against recommendation, and possibly attended another clinic. We were unable to follow up with this patient, and this case is also excluded from the study results. Finally, in the last case, fluid was extravasated toward the calf under the gastrocnemius mucscle, and severe swelling and ecchymosis lasted several days after surgery. The case improved after compression and ice was applied. This case was only followed up for 5 months after surgery, and was excluded because of the short follow-up time and because the patient was initially treated by a
42
S. H. KO AND J. H. AHN TABLE 4. Complications Complications
No. of Cases
Hematoma formation Technical error in not identifying the cyst wall Extravasation under gastrocnemius muscle Excessive shaving with progressive popliteal pain
1 case 2 cases 1 case 1 case
colleague Table 4 lists the complications expected with this procedure. DISCUSSION Kaenkasu et al.6 described recurrence after open resection of popliteal cysts as more than 50%, and in some cases joint stiffness develops. Rauschning and Lindgren2 also described recurrence. The recurrence rate of the popliteal cyst was very high (more than 50%) when cyst removal was performed with open excision using a posterior approach.6 Forty patients underwent repeat examination a mean 4 years after open excision of a popliteal cyst. Fifteen surgeries were followed by wound healing complications or tense swelling of the calf, simulating deep venous thrombosis, and at clinical follow-up a recurrent cyst was found in 63%.2 In our study, open resection was performed in 8 cases, but 6 cases included joint pain lasting more than 2 days and motion limitation recurrence occurred in 2 cases. Because we used a simple saline-irrigated motorized shaver in most cases, we did not touch the synovium, infrapatellar plica, or cartilage, and in some cases, we simply debrided degenerated meniscus after simple shaving of the cystic capsule. Therefore, most patients felt no pain. In 7 cases with severe degenerated arthritic joints, we injected hyaluronic acid or triamcinolon in the joint. We believe that the reason patients in this study experienced no pain or mild pain was because we did not perform cartilage-involving procedures such as abrasion arthroplasty or multiple drilling, microfracture, or synovectomy. Surgical time was short because we performed only irrigation. For some patients irrigation lasted only 10 minutes. However, sometimes simple meniscal shaving ignored complex problems within the joint. After simple irrigation within the joint using arthroscopy, most patients felt cool the day of surgery. There was no swelling because the inflamed synovium was not irrigated at surgery, and range of motion exercises were started the day after surgery. The popliteal cyst has an intra-articular pathol-
ogy.1,3 Jayson and Dixon3 described injury of the posterior horn of the medial meniscus, and Johnson et al.9 described medial meniscus tear in 68%, osteoarthritis in 81%, loose body in 38%, edema in 35%, and cartilage injury of the patellofemoral joint in 30%. In our study, medial meniscal tear in 11 cases (79%) was the most frequent injury. Noninvasive diagnosis is performed using sonogram, arthrogram, or MRI.10-12 MRI has a high specificity. Maffulli et al.11 reported identifying 52% of popliteal cysts on sonograms. The frequency of the posteromedial communicated hole is variable from 57% to 99%. Johnson et al.9 reported a frequency of 37%. The cause of the communication is age, trauma, degenerative arthritis, rheumatoid arthritis, edema, or meniscal injury.13,14 Johnson et al.9 typed cysts according to the anatomic structure of the posteromedial capsular wall. Type III has a transverse band and a communicated hole. Our cases showed the posteromedial connecting hole behind the capsular fold in 10 of 14 cases (71%). Sansone and De Ponti4 noted that intra-articular joint pathology must be corrected during the surgery and that recurrence is related to joint pathology. We visualized joint pathology and resected as needed during surgery. Lindgren14 described a valvular mechanism of the capsular fold on the posteromedial capsule and continuous unidirectional flow from the joint cavity to the cyst. If that is not corrected during the surgery, continuous flow of the joint fluid occurs and can cause postoperative recurrence. Sansone and De Ponti4 described the purpose of the operation as a correction of the joint pathology and a removal of the unidirectional flow. As a method of treating this hole, Childress1 described an augmentation using the tendon of the gastrocnemius and semimembranosus. Rauschning12 performed a pedicled graft of the medial head of the gastrocnemius, and Hughston et al.13 performed a simple capsular suture. However, in this method, the gastrocnemius and semimembranosus are incorporated together and the split is difficult. This can prevent precise capsular suture,4 and the suture site can rupture because of the increased pressure during the flexion and extension exercise of the knee joint.14 Lindgren and Willen15 noted that in about 50% of normal adults, a connection exists between the knee joint cavity and the gastrocnemius-semimembranosus bursa, even without a popliteal cyst. Sansone and De Ponti4 reported that no weakness of the joint structure and no complications occur despite an enlargement of
TREATMENT OF A LARGE RECURRENT POPLITEAL CYST
FIGURE 13. Diagram of cyst excision and removal of valvular mechanism.
the posteromedial capsular hole. In this study, we enlarged the posteromedial connecting hole about 5 mm for a conversion of the unidirectional flow to the bidirectional flow (Fig 13). If any shift of the fluid occurs between the joint and the cyst, spontaneous reabsorption occurs because of the bidirectional flow. In the future, the enlarged hole will be regenerated to a normal posteromedial capsule, and the fluid in the posterior side to the capsule will be resorbed because the cystic capsule was resected. Sansone and De Ponti4 described a connecting hole between the posterior of the medial meniscus and the extracapsular structure, but they did not resect the cystic wall, only enlarged the valvular mechanism and corrected the intra-articular pathology. Kanejasu et al.6 reported excellent results with shaving cystectomy and intra-articular synovectomy in the popliteal cyst. The authors performed direct shaving cystectomy of the popliteal cyst and approach to the posteromedial corner of the joint after correction of the joint pathology and an enlargement of the posteromedial connecting hole by a mosquito and shaver. Our paper is different from those of other authors in the correction of the valvular mechanism of the capsular fold, direct shaving cystectomy of the membraneous capsule of the cyst, and intra-articular pathology correction. In 2 cases, we shaved the capsular wall after using methylene blue injection, but effective cystectomy was performed without methylene blue preparation. Rauschning and Lindgren2 reported that the majority of recurrent cysts displayed wall irregularities. We found that, after approximately 3 needle aspirations, recurrent popliteal cysts show thick capsules and irregular, thick, and tortuous roots. Our cases were all
43
recurrent large cysts approximately 5 cm on sonography. We irrigated the joint after partial shaving of the only visible capsule of the popliteal cyst. We retained some part of the cystic capsule initially, but found no recurrence in any of the 14 cases. We believe that recurrence was not related to a retained capsule of the popliteal cyst wall, but to a retained posteromedial capsular fold of the valvular mechanism or to other unknown causes. Only one case showed mild prominence in the popliteal area, but this case has only been followed up for 6 months after surgery and was excluded from this study. We expect that the recurrent case will be included in long-term follow-up in our study. The significance of the valvular connection mechanism behind the capsular fold is described by Rauschning and Lindgren.16 That article reported that the presence of a valve mechanism was indicative of the absence of pathologic findings in the joint. Lindgren and Rauschning17 reported that cysts with a valvular connection were significantly larger than those without a valve mechanism. We believe that the existing surgical method of only correcting the joint pathology, not excising the recurrent cyst wall, is not a curable method. We suggest cystoscopic excision of the thickened wall and excision with enlargement of the valve mechanism in recurrent large popliteal cysts. In 1999, Sansone and De Ponti4 reported the results of arthroscopic treatment of the popliteal cyst. They noted optimal or good clinical results in 95% of patients treated. Kaenkasu et al.6 reported that arthroscopic cystectomy is a superior procedure for treating popliteal cysts associated with rheumatoid arthritis. In our cases, the clinical result was good except for some cases that were either followed up for a short term or not followed up. The weaknesses of this study are the limited cases and the need for more long-term follow up. CONCLUSIONS Cystoscopic excisional debridement of recurrent popliteal cyst and removal of the valvular mechanism of the capsular fold, which is a cause of recurrence, have shown good results. We effectively found intraarticular pathology and used simple irrigation and pain control via arthroscopy. The benefit is a simple procedure, short surgical time, decreased recurrence, decreased pain, rapidly improved range of motion, cosmetic effectiveness, short hospitalization, and easily converted open resection.
44
S. H. KO AND J. H. AHN
The possible complications of this procedure include incorrect identification of the popliteal cyst, hematoma formation, extravasation under the gastrocnemius muscle, possible retained cystic capsule, and recurrence. We suggest that arthroscopic direct shaving cystectomy and removal of the capsular fold of the valvular mechanism in large cysts greater than 5 cm (except in 1 case) for which conservative treatment that included 3 or more aspirations is an alternative to open resection. However, more long-term follow-up studies will be needed.
6.
7. 8. 9. 10. 11. 12.
REFERENCES 13. 1. Childress HM. Popliteal cysts associated with undiagnosed posterior lesion of the medial meniscus: The significance of age in diagnosis and treatment. J Bone Joint Surg Am 1970; 54:1487-1492. 2. Rauschning W, Lindgren PG. Popliteal cysts (Baker’s cyst) in adults: I. Clinical and roentgenological results of operative excision. Acta Orthop Scand 1979;50:583-591. 3. Jayson MIV, Dixon AStJ. Valvular mechanism in juxtaarticular cysts. Ann Rheum Dis 1970;29:415-420. 4. Sansone V, De Ponti A. Arthrosopic treatment of popliteal cyst and associated intra-articular knee disorders in adults. Arthroscopy 1999;15:368-372. 5. Burger C, Monig SP, Prokop A, Rehm KE. Baker’s cyst:
14. 15. 16. 17.
Current surgical status: Overview and personal results. Chirurg 1998;69:1224-1229. Kaenkasu K, Nagashima K, Yamauchi D, Yamakado K. A clinical study of arthroscopic cystectomy on politeal cysts associated with rheumatoid arthritis. Ryumachi 1997;37:761769. Kohnke J. Baker’s cyst. Chrurg 1999;70:217-218. Sansone V, De Ponti A, Paluello GM, Del Maschio A. Popliteal cysts and associated disorders of the knee. Int Orthop (SICOT) 1995;19:275-279. Johnson LL, van Dyk GE, Johnson CA, et al. The popliteal bursa (Baker’s cyst): An arthroscopic perspective and the epidemiology. Arthroscopy 1997;13:66-72. Hall FM. Baker cysts. Radiology 1997;203:577-578. Maffulli N, Regine R, Carrillo F, et al. Ultrasonographic scan in knee pain in athletes. Br J Sports Med 1992;26:93-96. Rauschning W. Popliteal cyst (Baker’s cyst) in adults: II: Capsuloplasty with and without a pedicle graft. Acta Orthop Scand 1980;51:547-557. Hughston JC, Baker CL, Mello W. Popliteal cyst: A surgical approach. Orthopedics 1991;14:147. Lindgren PG. Gastrocnemio-semimembranosus bursa and its relation to the knee joint: III: Pressure measurements in joint and bursa. Acta Radiol Diagn 1978;19:377-388. Lindgren PG, Willen R. Gastrocnemio-semimembranosus bursa and its relation to the knee joint: I. Anatomy and histology. Acta Radiol Diagn 1977;18:497-511. Rauschning W, Lindgren PG. The clinical significance of the valve mechanism in communication popliteal cysts. Acta Orthop Trauma Surg 1979;9:251-256. Lindgren G, Rauschning W. Clinical and arthrographic studies on the valve mechanism in communicating popliteal cysts. Acta Orthop Trauma Surg 1979;95:245-250.
Purpose: The purpose of this study was to evaluate the effectiveness of cystoscopic excisional debridement and removal of unilateral flow of the capsular fold of valvular mechanism in the posteromedial corner of the recurrent popliteal cyst. Type of Study: Retrospective review. Methods: From March 1998 to May 2000, we treated 14 cases of popliteal cyst by cystoscopic excisional debridement. The cysts were relatively large cysts, about 5 cm in diameter on sonography. Conservative treatment for about 1 year, with about 3 aspirations failed. The mean follow-up duration was 29.7 (24 to 36) months. We used Rauschning and Lindgren criteria for evaluations. We estimated surgical time. Patients underwent sonography 6 months and 1 year after surgery. Pain, range of motion, and recurrence were checked 1 year after surgery. Results: The average surgical time was 45 (31 to 58) minutes. The time to pain elimination and full range of motion was 1 or 2 days after surgery. No recurrence was noted in any patients. At the last follow-up, patients reported no discomfort or pain, and all had free range of motion. Preoperatively, Rauschning and Lindgren criteria were grade 0 in 0 cases; grade 1 in 3 cases; grade 2 in 10 cases; and grade 3 in 1 case. At 2 weeks after surgery, criteria were grade 0 in 13 cases and grade 1 in 1 case; at final follow-up evaluation, all were grade 0. Hematoma occurred in 1 case. However, in cases lost to follow-up and in short-term follow-up cases, technical errors occurred: not entering within the cyst in 2 cases, extravasion in 1 case, and recurrence in 1 case. Conclusions: A popliteal cystoscopic excisional debridement by motorized shaver and removal of the capsular fold of the valvular mechanism is an effective alternative to the open technique of treating popliteal cysts. Key Words: Recurrent popliteal cyst—Arthroscopic direct shaving cystectomy.
T
he preferred treatments for popliteal cysts have been conservative treatment or open resection. Many methods of surgical resection have been suggested, but the recurrence is high after simple resec-
From the Department of Orthopedic Surgery, Ulsan University College of Medicine, Ulsan (S.H.K.); and Samsung Medical Center School of Medicine, Sungkyunkwan University, Seoul (J.H.A.), South Korea. Portions of this article were presented at the meeting of the International Society of Arthroscopy, Knee Surgery, and Sports Medicine, Montreux, Switzerland, March 2001. Address correspondence and reprint requests to Sang Hun Ko, M.D., Ph.D., 290-3, JeonHa-Dong, Dong-Gu, Ulsan MetropolitanCity 682-714, South Korea. E-mail: [email protected] © 2004 by the Arthroscopy Association of North America 0749-8063/04/2001-3477$30.00/0 doi:10.1016/j.arthro.2003.10.017
tion.1,2 We noted that the popliteal cyst has intraarticular pathology,1,3 and Sansone and De Ponti4 suggested changing treatment strategies. As arthroscopic technique improves, the indication of arthroscopy is widening and associated intra-articular pathology can be effectively treated using arthroscopy.4-7 We tried arthroscopic direct shaving cystectomy of the thickened cyst wall in the recurrent popliteal cyst 3 times previously after the failure of long-term conservative treatment. We removed the one-way flow of the valvular mechanism after enlargement and removed the capsular fold in large cysts (about 5 cm). The purpose of this study was to evaluate the effectiveness of direct shaving cystectomy and removal of unilateral flow of the capsular fold of valvular mechanism in the posteromedial corner of the recurrent popliteal cyst.
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 20, No 1 (January), 2004: pp 37-44
37
38
S. H. KO AND J. H. AHN TABLE 1. Operation Time, Pain Duration, Interval of Full ROM, and Interval of Last Follow-up Case Age/Sex
FIGURE 1.
Time to absence of pain.
1 2 3 4 5 6 7 8 9 10 11 12 13 14
39/F 45/F 52/M 47/F 53/M 49/F 50/F 44/M 43/F 52/M 54/F 56/F 62/M 51/M
Operation Time 37 46 53 37 44 49 47 42 58 31 38 54 49 39
min min min min min min min min min min min min min min
Pain-Free Duration 24 24 24 48 24 24 24 24 24 24 24 24 72 24
hr hr hr hr hr hr hr hr hr hr hr hr hr hr
Interval of Last Full ROM Follow-up 48 24 48 48 48 48 48 24 24 48 24 48 48 48
hr hr hr hr hr hr hr hr hr hr hr hr hr hr
30 27 28 26 32 29 31 24 27 30 25 36 34 35
mo mo mo mo mo mo mo mo mo mo mo mo mo mo
METHODS From March 1998 to May 2000, 14 of 22 cases of popliteal cyst were treated arthroscopically. Patients included 6 men and 8 women. The control group was composed of the other 8 patients with presumed symptomatic popliteal cysts for which conservative management failed. The control group was treated with open surgery, but included 6 cases of joint pain lasting more than 2 days and motion limitation. Cysts recurred in 2 cases. Average patient age was 48 years (range, 39 to 62 years). We evaluated the surgical time, associated pathology, time to pain elimination (Fig 1), and time to full range of motion (ROM) (Fig 2). We used Rauschning and Lindgren knee scores for evaluation. The average follow-up time was 29.7 months (range, 24 to 36 months) (Table 1). Sonography was performed (Fig 3) before and after surgery. Recurrence
FIGURE 2.
Time to full range of motion.
was evaluated 6 and 12 months postoperatively (Fig 4). Preoperative magnetic resonance imaging was performed in 2 cases. The criteria for treatment included recurrent popliteal cysts with swelling, pain, limitation of motion, and nerve compression signs in the knee joint. All patients had undergone failed conservative treatment for approximately 1 year, and other systemic conditions were ruled out. The patients treated arthroscopically were those with relatively larger cysts, approximately 5 cm in diameter, evaluated by sonogram, for whom conservative treatment for 1 year with more than 3 aspirations failed. The cysts ballooned easily with injected normal saline. The reason these cases were selected
FIGURE 3. Sonographic findings show a large popliteal cyst in a 58-year-old woman.
TREATMENT OF A LARGE RECURRENT POPLITEAL CYST
FIGURE 4. rence.
39
One year after surgery, the sonogram shows no recurFIGURE 6. shaver.
The shaving of the outer cyst wall using the motorized
for arthroscopy is that we could expect well-developed thickened capsular walls and could easily introduce the shaver within the intracystic wall using arthroscopic instruments. The surgical method included using a marking pen and expanding the cyst with 20 mL of normal saline after verified aspiration of the yellowish cystic fluid. An 18-gauge needle was used with the patient in the lateral decubitus position under general or spinal anesthesia. In the lower pole of the ballooned cyst, the skin was incised about 3 mm with a No. 11 blade, and we introduced a blunt obturator and sheath. The arthroscope was inserted within the cystic wall. In the last 4 cases, we introduced subcutoscopy dissection by
inserted mosquette. We easily found the outer cyst wall (Fig 5). Diagnostic arthroscopy was performed within the intracyst wall. We inserted a motorized shaver on the contralateral side and performed direct shaving of the cyst wall with a suctioned motorized shaver (Figs 6 and 7). The tip of the shaver was pointed toward the inner side to avoid injuring the neurovascular structure, tendon, and muscle. We tried to avoid a lateral wall proximal to the neurovascular structure. Recurrent cysts have thickened, tortuous, and pedunculated roots. We tried to resect the roots completely using an arthroscopic scissor punch to avoid surrounding tissue (Figs 8 and 9). The hemovac suc-
FIGURE 5. The outer capsule of the recurrent popliteal cyst. We introduced the arthroscope subcutaneously in 4 cases.
FIGURE 7. The intracyst wall: the inner wall is shaved by the motorized shaver.
40
S. H. KO AND J. H. AHN
FIGURE 8. The punching of the thickened and tortuous roots using a meniscectomy punch.
FIGURE 10.
tion drain was inserted, and patient position was changed to supine. Diagnostic arthroscopy was performed using routine anterolateral, anteromedial, and superolateral portals. The posteromedial portal was used to visualize the posteromedial corner of the joint. After full examination of intra-articular joint pathology, we performed simple irrigation and simple meniscal shaving. An arthroscope was introduced to the posteromedial corner to verify a connecting hole to the cyst (Fig 10). If the fold connected to the cyst, we removed and resected the capsular fold completely and enlarged the valvular mechanism that was under the capsular fold (Fig 11). We cautiously introduced a shaver to the
portal that was not toward the medial side near the vascular tissue, and enlarged the capsular hole approximately 5 mm. If fibrous membranes, bands, and meniscal flaps are found within the cystic hole, we completely shaved and removed the material. If needed, we injected hyaluronic acid to joints with severe arthritis. We sometimes used triamcinolon injection for postoperative pain relief, and bupibarcaine 40 mL was also injected within the joint and cyst excision site. The hemovac suction drain was inserted in the joint, skin suture was performed, and a compressed elastic bandage was used.
FIGURE 9. The semimembraneous tendon after shaving of the popliteal cyst.
Visualization of the posteromedial connecting hole.
FIGURE 11. In the posteromedial corner of the knee joint, the valvular mechanism of the capsular fold is enlarged using a mosquito clamp and shaved.
TREATMENT OF A LARGE RECURRENT POPLITEAL CYST TABLE 2. Intra-articular Associated Lesion (n ⫽ 14) Associated Pathology
No. of Cases (%)
Degenerative change Medial meniscus tear Lateral meniscus tear Synovitis and synovial hypertrophy Chondromalacia and chondral defect Plica syndrome
10 (72%) 11 (79%) 3 (21%) 5 (36%) 4 (28%) 5 (36%)
RESULTS From March 1998 to May 2000, we performed surgery in symptomatic patients. Arthroscopic direct shaving cystectomy was performed in 14 of 22 cases. The surgical time from skin incision to suture of the arthroscopic portal averaged 45 minutes (31 to 58 minutes). The time to pain elimination and full ROM was 1 or 2 days after surgery (Table 1). The associated findings were degenerative cartilage damage in 10 cases (72%), medial meniscus tear in 11 cases (79%), lateral meniscal tear in 3 cases (21%), plica syndrome in 5 cases (36%), chondromalacia and cartilage defect in 4 cases (28%), and synovitis and synovial hypertrophy in 5 cases (36%) (Table 2). The knee joint showed full ROM in all cases by 1 year after surgery, and at final follow-up evaluation, no pain and no gait disturbances were seen. Complications included hematoma formation in 1 case, but this resolved after compression and rest. Functional evaluation was performed using Rauschning and Lindgren8 criteria (Fig 12). In the clinical evaluation of the results, we also followed guidelines proposed by Rauschning and Lindgren.2 The parameters considered were the subjective symptomatogy related to the presence of the popliteal cyst, pain and a posterior sense of tension in the popliteal fossa, and
FIGURE 12. The results of evaluation using Rauschning and Lindgren criteria.
41
TABLE 3. Clinical Evaluation of Results of Surgery According to Criteria of Rauschning and Lindgren Criteria Grade Grade Grade Grade
0 1 2 3
Before Surgery (no.)
2 Weeks After Surgery (no.)
After 1 year
Last Follow-up
0 3 10 1
13 1 0 0
14 0 0 0
14 0 0 0
the clinical importance of posterior swelling or reduction of ROM. All patients were evaluated by the following scale4: Grade 0: absence of swelling and pain, no limitation of range of motion. Grade 1: light swelling or a sense of posterior tension after intense activity, minimal limitation of ROM. Grade 2: swelling and pain after normal activity, ROM limitation less than 20°. Grade 3: swelling and pain even when resting, ROM limitation more than 20°. The grade at final follow-up evaluation was grade 0 in all cases (Table 3). In all cases, sonography was performed 6 and 12 months after surgery. No recurrence was found. Pain was reported for longer than 72 hours in 4 cases. One case developed mild hematoma at the site of the excised cyst, but this was improved with compression and rest, and popliteal pain lasted about 72 hours. Marked popliteal hematoma formation was reported in a case at a nearby college. However, because this case was not ours, it was excluded in this study. Two cases showed inadequate shaving because of a technical error. In one case, the arthroscopic trochar was not introduced within the cyst wall initially, and we opened the cyst and performed excision by scalpel. In another case, arthroscopic shaving of the cyst was performed aggressively, and the patient felt pain at the popliteal site. This patient was discharged against recommendation, and possibly attended another clinic. We were unable to follow up with this patient, and this case is also excluded from the study results. Finally, in the last case, fluid was extravasated toward the calf under the gastrocnemius mucscle, and severe swelling and ecchymosis lasted several days after surgery. The case improved after compression and ice was applied. This case was only followed up for 5 months after surgery, and was excluded because of the short follow-up time and because the patient was initially treated by a
42
S. H. KO AND J. H. AHN TABLE 4. Complications Complications
No. of Cases
Hematoma formation Technical error in not identifying the cyst wall Extravasation under gastrocnemius muscle Excessive shaving with progressive popliteal pain
1 case 2 cases 1 case 1 case
colleague Table 4 lists the complications expected with this procedure. DISCUSSION Kaenkasu et al.6 described recurrence after open resection of popliteal cysts as more than 50%, and in some cases joint stiffness develops. Rauschning and Lindgren2 also described recurrence. The recurrence rate of the popliteal cyst was very high (more than 50%) when cyst removal was performed with open excision using a posterior approach.6 Forty patients underwent repeat examination a mean 4 years after open excision of a popliteal cyst. Fifteen surgeries were followed by wound healing complications or tense swelling of the calf, simulating deep venous thrombosis, and at clinical follow-up a recurrent cyst was found in 63%.2 In our study, open resection was performed in 8 cases, but 6 cases included joint pain lasting more than 2 days and motion limitation recurrence occurred in 2 cases. Because we used a simple saline-irrigated motorized shaver in most cases, we did not touch the synovium, infrapatellar plica, or cartilage, and in some cases, we simply debrided degenerated meniscus after simple shaving of the cystic capsule. Therefore, most patients felt no pain. In 7 cases with severe degenerated arthritic joints, we injected hyaluronic acid or triamcinolon in the joint. We believe that the reason patients in this study experienced no pain or mild pain was because we did not perform cartilage-involving procedures such as abrasion arthroplasty or multiple drilling, microfracture, or synovectomy. Surgical time was short because we performed only irrigation. For some patients irrigation lasted only 10 minutes. However, sometimes simple meniscal shaving ignored complex problems within the joint. After simple irrigation within the joint using arthroscopy, most patients felt cool the day of surgery. There was no swelling because the inflamed synovium was not irrigated at surgery, and range of motion exercises were started the day after surgery. The popliteal cyst has an intra-articular pathol-
ogy.1,3 Jayson and Dixon3 described injury of the posterior horn of the medial meniscus, and Johnson et al.9 described medial meniscus tear in 68%, osteoarthritis in 81%, loose body in 38%, edema in 35%, and cartilage injury of the patellofemoral joint in 30%. In our study, medial meniscal tear in 11 cases (79%) was the most frequent injury. Noninvasive diagnosis is performed using sonogram, arthrogram, or MRI.10-12 MRI has a high specificity. Maffulli et al.11 reported identifying 52% of popliteal cysts on sonograms. The frequency of the posteromedial communicated hole is variable from 57% to 99%. Johnson et al.9 reported a frequency of 37%. The cause of the communication is age, trauma, degenerative arthritis, rheumatoid arthritis, edema, or meniscal injury.13,14 Johnson et al.9 typed cysts according to the anatomic structure of the posteromedial capsular wall. Type III has a transverse band and a communicated hole. Our cases showed the posteromedial connecting hole behind the capsular fold in 10 of 14 cases (71%). Sansone and De Ponti4 noted that intra-articular joint pathology must be corrected during the surgery and that recurrence is related to joint pathology. We visualized joint pathology and resected as needed during surgery. Lindgren14 described a valvular mechanism of the capsular fold on the posteromedial capsule and continuous unidirectional flow from the joint cavity to the cyst. If that is not corrected during the surgery, continuous flow of the joint fluid occurs and can cause postoperative recurrence. Sansone and De Ponti4 described the purpose of the operation as a correction of the joint pathology and a removal of the unidirectional flow. As a method of treating this hole, Childress1 described an augmentation using the tendon of the gastrocnemius and semimembranosus. Rauschning12 performed a pedicled graft of the medial head of the gastrocnemius, and Hughston et al.13 performed a simple capsular suture. However, in this method, the gastrocnemius and semimembranosus are incorporated together and the split is difficult. This can prevent precise capsular suture,4 and the suture site can rupture because of the increased pressure during the flexion and extension exercise of the knee joint.14 Lindgren and Willen15 noted that in about 50% of normal adults, a connection exists between the knee joint cavity and the gastrocnemius-semimembranosus bursa, even without a popliteal cyst. Sansone and De Ponti4 reported that no weakness of the joint structure and no complications occur despite an enlargement of
TREATMENT OF A LARGE RECURRENT POPLITEAL CYST
FIGURE 13. Diagram of cyst excision and removal of valvular mechanism.
the posteromedial capsular hole. In this study, we enlarged the posteromedial connecting hole about 5 mm for a conversion of the unidirectional flow to the bidirectional flow (Fig 13). If any shift of the fluid occurs between the joint and the cyst, spontaneous reabsorption occurs because of the bidirectional flow. In the future, the enlarged hole will be regenerated to a normal posteromedial capsule, and the fluid in the posterior side to the capsule will be resorbed because the cystic capsule was resected. Sansone and De Ponti4 described a connecting hole between the posterior of the medial meniscus and the extracapsular structure, but they did not resect the cystic wall, only enlarged the valvular mechanism and corrected the intra-articular pathology. Kanejasu et al.6 reported excellent results with shaving cystectomy and intra-articular synovectomy in the popliteal cyst. The authors performed direct shaving cystectomy of the popliteal cyst and approach to the posteromedial corner of the joint after correction of the joint pathology and an enlargement of the posteromedial connecting hole by a mosquito and shaver. Our paper is different from those of other authors in the correction of the valvular mechanism of the capsular fold, direct shaving cystectomy of the membraneous capsule of the cyst, and intra-articular pathology correction. In 2 cases, we shaved the capsular wall after using methylene blue injection, but effective cystectomy was performed without methylene blue preparation. Rauschning and Lindgren2 reported that the majority of recurrent cysts displayed wall irregularities. We found that, after approximately 3 needle aspirations, recurrent popliteal cysts show thick capsules and irregular, thick, and tortuous roots. Our cases were all
43
recurrent large cysts approximately 5 cm on sonography. We irrigated the joint after partial shaving of the only visible capsule of the popliteal cyst. We retained some part of the cystic capsule initially, but found no recurrence in any of the 14 cases. We believe that recurrence was not related to a retained capsule of the popliteal cyst wall, but to a retained posteromedial capsular fold of the valvular mechanism or to other unknown causes. Only one case showed mild prominence in the popliteal area, but this case has only been followed up for 6 months after surgery and was excluded from this study. We expect that the recurrent case will be included in long-term follow-up in our study. The significance of the valvular connection mechanism behind the capsular fold is described by Rauschning and Lindgren.16 That article reported that the presence of a valve mechanism was indicative of the absence of pathologic findings in the joint. Lindgren and Rauschning17 reported that cysts with a valvular connection were significantly larger than those without a valve mechanism. We believe that the existing surgical method of only correcting the joint pathology, not excising the recurrent cyst wall, is not a curable method. We suggest cystoscopic excision of the thickened wall and excision with enlargement of the valve mechanism in recurrent large popliteal cysts. In 1999, Sansone and De Ponti4 reported the results of arthroscopic treatment of the popliteal cyst. They noted optimal or good clinical results in 95% of patients treated. Kaenkasu et al.6 reported that arthroscopic cystectomy is a superior procedure for treating popliteal cysts associated with rheumatoid arthritis. In our cases, the clinical result was good except for some cases that were either followed up for a short term or not followed up. The weaknesses of this study are the limited cases and the need for more long-term follow up. CONCLUSIONS Cystoscopic excisional debridement of recurrent popliteal cyst and removal of the valvular mechanism of the capsular fold, which is a cause of recurrence, have shown good results. We effectively found intraarticular pathology and used simple irrigation and pain control via arthroscopy. The benefit is a simple procedure, short surgical time, decreased recurrence, decreased pain, rapidly improved range of motion, cosmetic effectiveness, short hospitalization, and easily converted open resection.
44
S. H. KO AND J. H. AHN
The possible complications of this procedure include incorrect identification of the popliteal cyst, hematoma formation, extravasation under the gastrocnemius muscle, possible retained cystic capsule, and recurrence. We suggest that arthroscopic direct shaving cystectomy and removal of the capsular fold of the valvular mechanism in large cysts greater than 5 cm (except in 1 case) for which conservative treatment that included 3 or more aspirations is an alternative to open resection. However, more long-term follow-up studies will be needed.
6.
7. 8. 9. 10. 11. 12.
REFERENCES 13. 1. Childress HM. Popliteal cysts associated with undiagnosed posterior lesion of the medial meniscus: The significance of age in diagnosis and treatment. J Bone Joint Surg Am 1970; 54:1487-1492. 2. Rauschning W, Lindgren PG. Popliteal cysts (Baker’s cyst) in adults: I. Clinical and roentgenological results of operative excision. Acta Orthop Scand 1979;50:583-591. 3. Jayson MIV, Dixon AStJ. Valvular mechanism in juxtaarticular cysts. Ann Rheum Dis 1970;29:415-420. 4. Sansone V, De Ponti A. Arthrosopic treatment of popliteal cyst and associated intra-articular knee disorders in adults. Arthroscopy 1999;15:368-372. 5. Burger C, Monig SP, Prokop A, Rehm KE. Baker’s cyst:
14. 15. 16. 17.
Current surgical status: Overview and personal results. Chirurg 1998;69:1224-1229. Kaenkasu K, Nagashima K, Yamauchi D, Yamakado K. A clinical study of arthroscopic cystectomy on politeal cysts associated with rheumatoid arthritis. Ryumachi 1997;37:761769. Kohnke J. Baker’s cyst. Chrurg 1999;70:217-218. Sansone V, De Ponti A, Paluello GM, Del Maschio A. Popliteal cysts and associated disorders of the knee. Int Orthop (SICOT) 1995;19:275-279. Johnson LL, van Dyk GE, Johnson CA, et al. The popliteal bursa (Baker’s cyst): An arthroscopic perspective and the epidemiology. Arthroscopy 1997;13:66-72. Hall FM. Baker cysts. Radiology 1997;203:577-578. Maffulli N, Regine R, Carrillo F, et al. Ultrasonographic scan in knee pain in athletes. Br J Sports Med 1992;26:93-96. Rauschning W. Popliteal cyst (Baker’s cyst) in adults: II: Capsuloplasty with and without a pedicle graft. Acta Orthop Scand 1980;51:547-557. Hughston JC, Baker CL, Mello W. Popliteal cyst: A surgical approach. Orthopedics 1991;14:147. Lindgren PG. Gastrocnemio-semimembranosus bursa and its relation to the knee joint: III: Pressure measurements in joint and bursa. Acta Radiol Diagn 1978;19:377-388. Lindgren PG, Willen R. Gastrocnemio-semimembranosus bursa and its relation to the knee joint: I. Anatomy and histology. Acta Radiol Diagn 1977;18:497-511. Rauschning W, Lindgren PG. The clinical significance of the valve mechanism in communication popliteal cysts. Acta Orthop Trauma Surg 1979;9:251-256. Lindgren G, Rauschning W. Clinical and arthrographic studies on the valve mechanism in communicating popliteal cysts. Acta Orthop Trauma Surg 1979;95:245-250.