Objective To investigate the diagnosis and management countermeasures of degenerative lesions of the intercondylar fossa of the femur. Methods The group consisted of 70 knees, 15 males and 55 females, aged 31-74 years, with an average of 60.4 years, mainly presenting with anterior or indeterminate localized dull pain in the knee, progressive joint extension and flexion disorders, and recurrent joint effusion. Arthroscopically the disease presents with two categories: bone to bone impingement and bone to ligament and soft tissue impingement. Treatment was performed by arthroscopic enlargement of the intercondylar fossa of the femur plus microscopic arthroplasty.
Results At follow-up of 48 cases and 50 knees with an average of 39 months, postoperative joint function exceeded the preoperative level, especially joint extension and flexion dysfunction improved significantly.
Conclusion Arthroscopy can effectively complete the diagnosis and treatment of this disease, and arthroscopic enlargement of the intercondylar fossa of the femur is a good method to treat this disease.
From 1996 to 2003, a total of 192 knees were treated arthroscopically for osteoarthritis of the knee, of which 70 knees were treated with degenerative lesions of the intercondylar fossa of the femur. The main lesions were degenerative stenosis of the intercondylar fossa of the femur, osteophyte growth or formation of osteophytes at the tibial crest stop of the ACL, causing the anterior border of the femoral intercondylar fossa exit structure to rub against the top of the ACL and intercondylar fossa during knee extension and flexion, resulting in corresponding clinical symptoms. The main symptoms are dull pain in the anterior part of the knee or indeterminate positioning, progressive joint extension and flexion disorders, and recurrent joint effusion. Arthroscopic examination reveals partial rupture of the ligament fibers or reduction of the movable range of the ACL and the intercondylar fossa structure due to friction and compression. In this article, we analyzed the arthroscopic presentation and the efficacy of arthroscopic intercondylar fossa enlargement and debridement in 70 patients with intercondylar impingement of the knee.
Clinical data
I. General information
There were 68 cases of 70 knees in this group, 2 cases were double knees, 15 knees in men and 55 knees in women; age ranged from 31 to 74 years, with an average of 60.4 years; 37 cases were left knees and 33 cases were right knees, with a ratio of 1.1:1 between left and right; disease duration ranged from 3 to 37 years, with an average of 21.5 years. There were 25 knees with combined meniscal injury, 11 knees with synovial chondromatosis, 9 knees with knee entropion, and 3 knees with rheumatoid arthritis.
II. Clinical presentation and radiological examination
All patients had a history of knee pain and progressive knee extension and flexion disorders with a mean flexion and extension range of 6.8°~115.1°. 30 knees had a history of interlocking and 25 knees had a history of recurrent joint effusion. The radiographic findings on the frontal and intercondylar fossa were uneven density of the intercondylar fossa in 55 knees, shallowing of the fossa in 47 knees, osteophytes in 49 knees, and osteophyte formation around the intercondylar crest of the tibia in 26 knees. 52 knees had a preoperative diagnosis of degenerative intercondylar femoral impingement, and the other 18 knees did not have a clear preoperative diagnosis of degenerative intercondylar femoral impingement.
III. Surgical approach and intraoperative findings
Anesthesia: epidural. A tourniquet is usually not required, but can be put on first for backup. To reduce bleeding, epinephrine (1mg/3000ml) can be added to the flushing fluid in appropriate amounts. Operation: Arthroscopic surgery is routinely performed with anteroinferior and anterolateral approaches. The intercondylar fossa should be inspected dynamically, i.e., when the assistant extends and flexes the joint, the surgeon should observe the relative relationship between the anterior edge of the femoral intercondylar fossa exit and the ACL, the ligament tibial crest stop and its surrounding bone growth with a 30° mirror from the anterior-external approach, and determine the impact site and the type of impact, then treat other intra-articular lesions before entering the surgical instrument from the anterior-internal approach to perform intercondylar fossa enlargement. The intercondylar fossa was reexamined dynamically to determine that the anterior cruciate ligament impingement factor had been eliminated. There are two types of degenerative intercondylar fossa lesions seen intraoperatively: (1) the ACL is impinged, abraded, and pinched by the degenerated intercondylar fossa and the surrounding bony flab; and (2) the femoral condyle and the tibial intercondylar ridge are impinged by the proliferating bony flab around each other. Both of these conditions can cause joint motion limitation and pain. Postoperative treatment: appropriate amount of local anesthetic, epinephrine and sodium hyaluronate were placed in the joint, and large cotton pads were wrapped with pressure for 3 days. Functional exercises were started on the 1st postoperative day, and the patient was discharged from bed after 2~3 days, and the stitches were removed in one week. Regular outpatient review and guidance for patient rehabilitation for 3-6 months. Complications: one case of planer tip breaking in the joint (subsequently removed microscopically), no complications affecting the efficacy such as infection, vascular nerve injury and postoperative joint adhesions. The average operation time was 82 minutes.
IV. Follow-up results
Table 1 Table of preoperative and postoperative Lysholm functional scores (χ±s)
Tab.1 Lysholm score
Male
Male
Female
Female
Total(knee)
Total(knee)
Preoperative
Preoperation
Postoperation
Postoperation
12
38
50
47.8±12.1
86.3±6.6
In the 48 cases of 50 knees (2 cases of both knees) in which follow-up was obtained from 6 to 72 months (mean 39 months) in 70 knees, joint function exceeded the preoperative level after 3 months postoperatively, especially joint extension and flexion dysfunction improved significantly from a mean of 6.8° to 115.1° in extension and flexion before surgery to a mean of 1.3° to 126.6? with a mean increase of 5.5° in extension and 11.5° in flexion. Lysholm scores were 47.8 (poor) before surgery and 86.3 (good) after surgery, p< 0.001 (t-test, see Table 1). 1 knee had an artificial knee replacement 3 years after surgery because of a periarticular closure infection that limited joint motion, and the other knee (combined internal derangement) had an artificial knee replacement 2 years after surgery because of worsening symptoms. The other knee (combined with knee entropion) was operated 2 years after surgery. The rest of the patients did not have any postoperative exacerbation and required reoperation.
DISCUSSION
I. Etiology
The common causes of degenerative lesions in the intercondylar fossa of the femur are: (1) meniscal injury and imbalance of load on the internal and external interarticular compartments due to malalignment of the joint forces; (2) articular cartilage degeneration secondary to long-term synovial lesions; (3) improper selection of the ligament stop for anterior cruciate ligament reconstruction. In this group of patients, there was osteophyte hyperplasia at the top and both sides of the intercondylar fossa in 61/70 knees, tibial intercondylar crest or paracondylar crest formation causing elevation or impingement of the ACL stop in 31/70 knees, inversion of the knee to varying degrees in 9/70 knees, and free bodies or synovial chondromas stuck around the ACL stop in 13/70 knees.
II. Arthroscopic diagnosis and staging
(A) Diagnosis
Degenerative intercondylar fossa lesions are part of the symptoms of osteoarthritis and often overlap with other manifestations of knee degeneration, making the preoperative diagnosis not easy. Arthroscopic examination reveals the absence of synovial membrane on the surface of the ligament, angulation, separation and rupture of fibers, hyperplasia on the top and sides of the intercondylar fossa, and hyperplasia on the intercondylar crest of the tibia or its surrounding bones, which elevates the ligament stop and impinges on the corresponding parts of the ligament and femoral condyle.
(B) Arthroscopic typing
Through arthroscopic dynamic observation, we classify the arthroscopic manifestations of the disease according to the mode of impingement and the relative relationship between the anterior cruciate ligament and the anterior exit of the intercondylar fossa of the femur.
1. Bone to bone impingement.
During knee extension and flexion, the anterior cruciate ligament tibial stop (Figure 1) or the surrounding hyperplastic bony flank impinges on the top and sides of the femoral condyles, manifesting mainly as limited joint extension, with damage and degeneration of cartilage visible in the impinged femoral condyles (31/70).
2. Bone and ligament and soft tissue impingement.
Degeneration of the intercondylar fossa was the most common damage to the ACL by abrasion (46/70). Bone growth at the top of the intercondylar fossa, on both sides, or at the tibial stop, causes the ACL to be worn by it during joint extension and flexion, and the synovial membrane on the surface of the ligament is missing and the fibers are separated and partially ruptured, resulting in symptoms and signs, mainly pain in extension and flexion of the knee with limited motion (Figure 2). The degenerative narrowing of the intercondylar fossa creates a pinching of the ACL (15/70). The top and both sides of the intercondylar fossa become coalesced and pinch the beginning of the femoral stop of the ACL, reducing the range of motion of the ligament and limiting the joint motion, primarily with limited motion and secondarily with pain (Figure 3). When both conditions are present, signs and symptoms of wear and tear and pinching are evident (9/70), which is a more severe form of osteoarthritis, with severe motion limitation and pain (Figure 4).
In addition, sometimes larger bony free bodies or synovial chondromas can become lodged in the intercondylar fossa or surrounded by the synovial membrane (Figure 5), affecting the function of the ACL and often resulting in joint locking and limitation of motion (13/70 knees).
III. Discussion of treatment countermeasures for degenerative intercondylar fossa lesions
Previously, most of the reported intercondylar fossa enlargement procedures were performed during open arthroplasty, which is associated with significant injury, slow recovery, and high complication rate, and not many patients are willing to undergo open surgery. Arthroscopic enlargement of the intercondylar fossa is mostly performed during and after cruciate ligament reconstruction for intercondylar fossa impingement [1], [2], [3], whereas microscopic surgery for degenerative intercondylar fossa lesions due to osteoarthritis is less frequently reported [4], [5], [6]. In this group of patients, the technical characteristics of the microscopic surgery were as follows: firstly, to distinguish whether it was a bone-on-bone impingement or a bone-on-ligament and other soft tissue impingement; if it was a bone-on-bone impingement, the removal of the tibial plateau bone was the main focus, and the revision of the femoral condyle was supplementary. If the ACL is heavily pinched, the instrumentation should be entered alternately from the anterior-internal and anterior-external approaches, and the bone superfluous caused by the pinched ligament should be carefully chipped along the medial and lateral sides of the pinched ligament stop to enlarge the condylar fossa. When ACL wear and pinching are obvious, the lesion is often heavy, and the surgical instruments have little space to operate, so it is easy to collide with each other and damage the ACL, so it is necessary to remove the synovial membrane and subpatellar fat pad near the intercondylar fossa to make the view clear, so as not to damage the ligament or the instruments. . The free body or synovial chondrosarcoma may stay or get stuck near the ACL, or even not be easily detected by synovial wrapping and ligament occlusion, so it should be thoroughly explored, and if necessary, it can be combined with intraoperative X-ray fluoroscopy to prevent missing. The joint can be tested at 90° and in extension before the end of surgery to ensure that the joint function can be improved after surgery.
The possibility of recurrence after enlargement of the degenerative intercondylar fossa exists. Although we have not yet seen any cases requiring a repeat intercondylar fossa enlargement, the probability of patients requiring a repeat intercondylar fossa enlargement will increase over time as joint degeneration continues.
Complications of arthroscopic enlargement of the degenerative intercondylar fossa are theoretically numerous, such as vascular nerve injury, lower extremity venous thrombosis, ACL injury, infection, postoperative intra-articular blood leakage, massive infiltration of joint perfusion into soft tissue, postoperative joint adhesions, and damage to arthroscopic instruments. Except for one case of damage to the arthroscopic instruments, the above mentioned complications did not occur in this group of patients, especially in the patient with postoperative joint adhesions. The experience was based on good intraoperative visualization, skillful and standardized arthroscopic operation, good spatial sensation, and specific postoperative rehabilitation training.
There is no exact explanation for the large difference in the gender ratio of 1:4.7 in this group of patients. It is speculated that it may be related to the greater sex hormone changes in women during menopause, which play a role in the degeneration of articular cartilage. The answer to the question remains to be further investigated.
Although the intercondylar fossa has basically recovered its normal shape after surgery and the obstruction of ACL in motion has been eliminated, the joint capsule and ligaments have different degrees of contracture due to the long duration of the disease, and although the extension and flexion function of the joint has improved immediately after surgery, it is only the beginning of recovery. Therefore, rehabilitation training should also be paid attention to accordingly. All patients in this group were given preoperative education on rehabilitation, and postoperative rehabilitation was carried out according to the plan (at least 6 months, with extension and flexion of the knee and quadriceps exercises as the main focus). According to the follow-up results, the postoperative knee function could be recovered quickly, and the joint function and extension and flexion range exceeded the preoperative level after 3 months, and the recovery process could last 6-12 months. Therefore, raising awareness of degenerative intercondylar fossa lesions and emphasizing appropriate intercondylar fossa enlargement-plasty under arthroscopy with systematic and effective rehabilitation training can improve the efficacy of microscopic cleanup for osteoarthritis. It has positive significance in extending the service life of the diseased joint and improving the quality of life of patients.