Congenital knee dislocation is a rare anomaly. We failed to find any previous reports in the literature of cases neglected until the individual was in the fifth decade of life or of cases associated with femoral deformities. We report a case of severe neglected bilateral congenital knee dislocation in a forty-three-year-old man.
The patient was informed that data concerning the case as well as videos would be submitted for publication, and he consented.
A forty-three-year-old man presented with severe neglected bilateral congenital knee dislocation. He walked on his four limbs, and the main symptom on presentation was low-back pain from this abnormal posture and painful callosities behind the knees (Fig. 1). The deformities had been neglected since birth because of the lack of adequate financial resources and accessible specialized medical centers. As the deformities worsened over time because of the development of adaptive osseous changes, the only solution offered to him was amputation. The deformities had a major psychological and social impact on his life. He was nearly confined to his home, ashamed to be active in the community. His walking ability was limited to a few meters. He had a custom-made motorcycle for transportation that could be fully operated manually. He was employed as an observer in a flour mill but he was frequently absent from work.
On examination, the patient could stand only on the backs of his knees with his legs extended in front of him. He could lie on his side with his legs alongside his trunk. A general physical examination revealed coincidental café au lait patches on his back and a mild degree of dorsolumbar kyphoscoliosis. Examination of the knees revealed atrophic distal thigh muscles and multiple callosities in the popliteal spaces as a result of standing. Both knees had a hyperextension deformity of 135° but could be extended more to reach 145°. Pulsations of the popliteal arteries were felt in the anteromedial aspects of the knees. Marked external tibial torsion was present bilaterally (Fig. 1). The ankle joints and feet were normal except for their abnormal orientation. The hip joints had normal amounts of flexion, extension, adduction, and abduction. However, there was a marked external rotation deformity of both hips, allowing the patient to place his legs and feet alongside his trunk during sleep. No other musculoskeletal anomalies were found. The findings of the neurological examination were normal, and the vascular status distal to the level of the knees was normal.
Plain radiographs demonstrated a distal femoral recurvatum deformity of 115° bilaterally. A false articulation was present between the proximal part of the tibia and the anterior surface of the distal part of the femur (Fig. 2). The femoral condyles were hypoplastic and located posterior and distal to the newly formed knee joint. The patellae were hypoplastic and located at the level of the tibial tuberosities. Continuous-wave Doppler studies were performed to assess the patency and delineate the course of the major vessels. Computed tomographic scans revealed a markedly atrophic soft-tissue envelope of the deformed distal portions of the thighs.
We planned to correct this deformity with a single-stage osseous procedure with excision of a trapezoid-shaped segment from the distal part of the femur to create a horizontal knee joint and to restore alignment of the femoral shaft to the tibia. The stable painless false knee joint was intended to be left undisturbed. Therefore, the aim was to correct the recurvatum deformity of the distal part of the femur with femoral shortening and thereby eliminate the need to lengthen or release any of the soft tissues of the thigh (Fig. 3).
Operative Technique
With the patient lying supine on a radiolucent orthopaedic table, a direct lateral approach was used. A 30-cm curved skin incision extending from the distal 20 cm of the femur to the proximal 10 cm of the leg was performed. Skin flaps were dissected to explore and carefully protect the neurovascular bundle. The sciatic nerve trunk emerged from the posterolateral aspect of the thigh at the apex of the femoral recurvatum deformity deep to the deep fascia, where it divided into its two terminal branches. The common peroneal nerve ran from the point of origin, crossing over the lateral surface of the femur and then running along the anterolateral aspect of the false knee joint, to enter the anterior compartment of the leg midway between the fibular head and the tibia superficial to the normal proximal tibiofibular articulation. The tibial nerve ran from the point of origin along the lateral aspect of the deformed femur and the lateral aspect of the false knee joint to enter the lateral compartment of the leg along the lateral surface of the fibular head before making a final turn into the posterior compartment of the leg. Popliteal pulsation was frequently checked on the anteromedial aspect of the knee, but the artery itself was not dissected. The iliotibial band was displaced anteriorly within the concavity of the distal femoral recurvatum, down to its insertion into the Gerdy tubercle. We incised the posterior portion of the iliotibial band together with the vastus lateralis and vastus intermedius to expose the femur subperiosteally. Both vasti were atrophic. The capsule of the false knee joint was visualized laterally and anteriorly during the dissection; however, we did not attempt to open it or explore the joint. The planned resection was marked with multiple drill-holes with use of a 3.2-mm drill-bit. With a 10-mm osteotome, the drill-holes were connected, completing the osteotomy, and the trapezoidal bone wedge was removed. The ends of the osteotomy site were then reduced. A contoured broad dynamic compression plate was applied across the knee joint and fixed to the proximal and distal femoral fragments and to the proximal part of the tibia to provide support for the osteotomy site during healing.
At the conclusion of the procedure, we observed the following.
- The posterior neurovascular bundle was not in its normal position in the midline of the popliteal fossa, and the tibial and common peroneal nerves were displaced to the posterolateral side. However, they assumed a straight course after realignment.
- The popliteal artery relocated to the posteromedial side of the knee and assumed a straighter course as well.
- The iliotibial band remained in a more lateral position.
- The false knee joint was aligned better with the shaft and had a range from 0° to 10° of hyperextension.
The wound was closed in layers over a suction drain.
The second limb was corrected with use of the same steps ten days later. The pathological and surgical findings in the right and left limbs were identical. The duration of the first operation was 185 minutes, and the duration of the second was 140 minutes. Blood loss was estimated to be 450 and 350 mL in the first and second procedures, respectively.
Postoperative Follow-up and Results
No neurovascular compromise was present postoperatively. The drains were removed after forty-eight hours. Non-weight-bearing walking with crutches was started four weeks after the second operation. Follow-up radiographs demonstrated union of the osteotomy site at thirteen weeks postoperatively on the right side and at eighteen weeks postoperatively on the left side. Weight-bearing on the right side was allowed after union (at thirteen weeks) with partial weight-bearing on the left side. The plates were removed three months after union was achieved on the right and left sides (at twenty-six and thirty-one weeks, respectively).
The patient was then followed both clinically and radiographically every six months to check for pain, loss of correction, and instability. At the latest follow-up examination, eleven years postoperatively, there was 25° of varus on the left side and 27° of varus on the right side. The correction achieved at surgery was maintained (Fig. 4), and the patient had no residual pain, instability, or refracture. The range of motion of both knees was between 0° and 10° of hyperextension. The patient could walk unsupported for up to 500 m (see Appendix), but his walking tolerance increased with the use of forearm crutches (see Appendix). He was able to sit on a chair behind his desk (see Appendix) and to drive a regular motorcycle using his legs. His work ability, his community activities, and even his sexual activity improved dramatically following the surgery (Fig. 5).
Congenital dislocation of the knee joint is a rare anomaly occurring in isolation or in combination with other congenital anomalies. It was first described by Chatelaine in 18221 and then by Bord in 18342. The cases fall into three categories: (1) sporadic cases of congenital dislocation of the knee; (2) patients with multiple dislocations; and (3) those with syndromes that are characterized by multiple joint dislocations, such as Larsen syndrome or arthrogryposis3.
Congenital knee dislocation is classified as recurvatum, subluxation, or dislocation. Recurvatum occurs when the knee hyperextends by >15° but has full flexion and is radiographically normal. Subluxation is present when the knee hyperextends by >15°, has some restriction of flexion, and has radiographic evidence of subluxation. Dislocation is present when the knee is unstable and truly dislocated1.
The main pathological features of congenital knee dislocation are shortening of the quadriceps femoris tendon, a tight anterior aspect of the joint capsule, an elongated attenuated anterior cruciate ligament, and hypoplasia of the suprapatellar bursa4. Approximately half of the cases are complicated by a valgus deformity of the knee4.
To the best of our knowledge, there have been no previously reported cases of dislocation of the knee left untreated until the fifth decade of life. We did not find any reported case after the age of nine years4-6. In the most severe reported case, hyperextension ranged from 0° to 45°7, whereas it ranged between 135° and 145° in our case.
Surgical correction of a neglected congenital knee dislocation has usually been described as an extensive soft-tissue release and lengthening of the extensor mechanism. The quadriceps needs to be exposed and mobilized distally from the entire femoral shaft, to which it is adherent, as much as the femoral nerve branches will allow7. The quadriceps tendon together with the tendon of the rectus femoris may need to be lengthened with use of a long inverted v-incision8. The medial hamstrings, iliotibial band, and lateral intermuscular septum may need to be lengthened as well9. We found no reports in the literature of any osseous procedures that can be performed for realignment in neglected cases of congenital knee dislocation.
In our decision-making process, we considered four treatment options: (1) gradual soft-tissue stretching with use of the Ilizarov device to first reduce the knee joint, followed by osseous correction of the recurvatum deformity; (2) an opening wedge osteotomy of the distal part of the femur and gradual correction with the Ilizarov device with the false knee joint left undisturbed; (3) knee disarticulation with prosthetic replacement; and (4) a one-stage osseous correction through femoral shortening.
Because of the severe osseous deformities in our patient, soft-tissue releases did not seem to be a reasonable option. We also did not consider gradual soft-tissue stretching with use of the Ilizarov device to reduce the knee joint followed by an osteotomy for the recurvatum deformity because, with the long-standing neglected dislocation, the articular surfaces of the femoral condyles would have been too deformed to permit any functional motion or weight-bearing.
Ilizarov gradual correction through distraction osteogenesis at the site of an opening wedge osteotomy has many problems10 such as poor patient compliance, pin track infections, delayed union or nonunion, and iatrogenic neurovascular injury (which may have been more likely in our patient because of the abnormally located neurovascular bundles). As for the option of bilateral knee disarticulation with prosthetic replacement, amputation is not socially accepted in our community and was refused by the patient.
Single-stage acute osseous correction with removal of a trapezoidal section of the femur was our treatment of choice. It allowed correction of the osseous deformity without the need for soft-tissue lengthening or release, enabling the patient to return to work in a relatively short time. We intended to leave the false articulation between the tibial plateau and the anterior aspect of the distal part of the femur undisturbed as it was stable and not painful. Although this joint had a very limited range of motion and the patient functioned as if he had bilateral knee fusion, his functional and psychological state was dramatically improved by his achievement of an upright posture. At the time of writing, he was completely satisfied with the result of the surgery, as he could walk unsupported, perform activities of daily living in a better way, perform his job better, get in and out of public transportation vehicles using hip motion and his strong upper limbs, and drive a regular motorcycle.