Erdheim-Chester disease was named after William Chester, who described the disease in 1930, and the Viennese pathologist Jakob Erdheim. Erdheim-Chester disease is a rare non-Langerhans cell histiocytosis that causes a systemic disease with involvement of the tubular long bones, sparing the axial skeleton, as well as the hands and feet1. The prognosis depends in large part on the extent and distribution of extraosseous manifestations, which most commonly includes diabetes insipidus; these manifestations can also include involvement of the retroperitoneum, skin, lung, and heart and include painless bilateral exophthalmus in >50% of cases2-4. Together with bone pain that arises from bone destruction affecting nociceptors within periosteum and bone marrow, mainly of the lower limbs, these clinical symptoms lead to the diagnosis of Erdheim-Chester disease. The diagnosis is usually based on typical radiographic findings, with symmetric bilateral osteosclerosis involving metaphyseal and diaphyseal regions of the long bones with sparing of the epiphyses. Bone scintigraphy reveals increased tracer uptake in Erdheim-Chester disease lesions, while magnetic resonance imaging shows replacement of the normal fatty bone marrow as well as periostitis2-6.
Our report highlights a case of severe bilateral knee joint destruction and varus deformity in a fifty-eight-year-old man with Erdheim-Chester disease and describes the clinical details, technical aspects of surgery, and short-term outcome one year after surgery. To our knowledge, this is the first report of a joint arthroplasty (specifically, bilateral total knee replacement) in a patient with Erdheim-Chester disease. The patient was informed that data concerning the case would be submitted for publication, and he consented.
This fifty-eight-year-old male winegrower with a body-mass index of 39.5 kg/m2 and a five-year history of Erdheim-Chester disease developed progressive motion-dependent pain and varus deformity in both knees two years prior to presentation. There was no history of trauma, and the pain prevented him from working at his farm. At the time that the patient was diagnosed with Erdheim-Chester disease, extraosseous disease manifestations included the posterior pituitary gland causing diabetes insipidus, the retroperitoneum causing urinary stasis and renal failure, and pulmonary disease. Treatment consisted of a course of chemotherapy, dialysis, intermittent medication with vitamin D, corticosteroids, use of a budesonide inhaler, and long-term oral desmopressin.
Clinical examination revealed severe varus deformities and effusions of both knees and moderate edema of both feet and ankles. Both knees had a painful arc of motion from full extension to 100° of flexion. There was 10 mm of medial opening of both knees with valgus stress in 20° of knee flexion, but not in extension. There was no muscle imbalance, the patellae were stable, and the Q-angles were normal.
Radiographs revealed characteristic bone involvement of Erdheim-Chester disease with bilateral heterogeneous osteosclerosis of the diaphyses, metaphyses, and epiphyses of the femur and tibia with obliteration of marrow spaces as well as severe osteoarthritic joint destruction and varus deformities in both knees with bilateral defects of the medial tibial plateau (Fig. 1). Total knee arthroplasties were done in a staged manner, with the surgery first done on the more painful right knee and then performed on the left knee six months later.
Preoperative lateral radiograph of the right knee (A), anteroposterior weight-bearing radiograph of the right knee (B), anteroposterior weight-bearing radiograph of the left knee (C), and lateral radiograph of the left knee (D) showing severe joint destruction and genu varum bilaterally with defects in the medial tibial plateaus. Furthermore, symmetric bilateral involvement of the bone of the diaphyses, metaphyses, and epiphyses of the femur and tibia by the Erdheim-Chester disease, with heterogeneous osteosclerosis, thickening of the cortex, blurred corticomedullary margins, and obliterated marrow cavities, can be seen.
The surgical approach to the right knee was via a standard medial parapatellar arthrotomy. Severe villous synovitis was present, and the synovium was debrided (Fig. 2, A). There was complete destruction of the articular surfaces with bone erosion on the femur, particularly on the medial side, with a corresponding defect of the medial tibial plateau (Fig. 2, B); however, the retropatellar knee compartment showed an almost intact articular cartilage surface. The cruciate ligaments and menisci were resected. Because of the massive osteosclerosis of the trabecular bone and obliteration of the marrow space, it was necessary to place the intramedullary alignment guide of the Press Fit Condylar (PFC) total knee arthroplasty system (DePuy Orthopaedics, Johnson & Johnson, Kirkel, Germany) for the distal cut of the femur in the correct position by drilling the femoral canal under fluoroscopic control. The external tibial alignment guide was employed for tibial orientation. The osseous cuts required three saw blades for each cut as a result of the osteosclerosis of the distal part of the femur and proximal part of the tibia. Following ligament balancing of the extension gap, the final cuts of the femur with the saw guide required two additional saw blades. Some of the resected bone of the femur was used to augment the osseous defect on the medial tibial plateau, and the graft was fixed with two 3.5-mm threaded screws 4 cm in length (Fig. 2, C). After final tibial and femoral preparation, 2-mm drill holes were placed throughout the sclerotic surfaces to facilitate bonding of bone and bone cement during implantation of the components (Fig. 2, C). Patellar replacement was not necessary because of the remaining cartilage layer on the articular surface.
Intraoperative findings during total knee replacement surgery on the right side. A: After medial parapatellar arthrotomy, a massive villous synovitis (arrow) partly covering the articular surfaces of the right knee became evident. B: After debridement of the inflamed soft tissue, the advanced stage of osteoarthritis and joint destruction became evident. C: Surgical management consisted of osseous augmentation of the defect on the medial tibial plateau, with the graft fixed with threaded screws (arrow), and bone cuts with correct alignment. Obtaining the correct alignment was difficult because of the massive osteosclerosis, which can be seen among the 2-mm drill holes that were placed to help bonding of bone and cement.
Similar findings were present in the left knee. The same posterior cruciate ligament-substituting total knee arthroplasty system and bone augmentation technique for the tibial defect were used. However, in order to overcome the difficulties of using an intramedullary femoral guide during the first surgery, a navigation system (VectorVision; BrainLAB, Feldkirchen, Germany) was used to facilitate better positioning of the femoral and tibial components (Fig. 3).
Lateral radiograph of the right knee (A), anteroposterior weight-bearing radiograph of the right leg (B), anteroposterior weight-bearing radiograph of the left leg (C), and lateral radiograph of the left knee (D) made twelve and eighteen months after the total knee arthroplasties on the left and right sides, respectively, show correct implantation of the components and straight knee axes on both sides.
The patient was allowed incremental weight-bearing on crutches over six weeks postoperatively and vigorous physical rehabilitation without limitation of knee motion on the day of the operation. Standard and full-weight-bearing radiographs of both knees immediately after the surgery and at six, twelve (Fig. 3), and eighteen (only the right knee) months postoperatively revealed correct positioning of the implants. At the time of the latest follow-up examination, twelve months after the surgery on the left knee and eighteen months after the surgery on the right knee, the patient had no symptoms in either knee and had a range of knee motion from full extension to 110° of flexion bilaterally without signs of instability.
The renal insufficiency with concomitant diabetes insipidus and lung fibrosis worsened after each surgical procedure, causing water retention in the lung and edema in the periphery despite adjustment of the desmopressin medication. These conditions were treated with oxygen administration, insertion of a urinary catheter, and diuretic therapy. At twelve and eighteen months after the surgical procedures, the patient was very satisfied with the outcomes, including the mobility and quality of life that he had regained.
The metaphyses and diaphyses of the long bones, especially the tibia and femur, are common sites of manifestation of Erdheim-Chester disease6. However, destruction of the articular surfaces of both knees, as described in our case, is uncommon. Of note, a high degree of synovitis was found within the knee joints (Fig. 2, A). We can only speculate as to whether this inflammation resulted in cartilage destruction within the knees.
When performing the bone cuts in our patient with Erdheim-Chester disease, we encountered notable hardness of the osteosclerotic bone, necessitating repetitive replacements of the saw blade. There are only limited reports on the technical difficulties related to the performance of arthroplasty in patients with osteosclerotic bone or osteopetrosis, but these patients have not had increased rates of aseptic loosening7,8. However, the pattern of bone infiltration and histopathological changes in Erdheim-Chester disease differs from that in osteopetrosis3. Therefore, further follow-up over several years is required to determine the outcomes of the total knee replacements in our patient with Erdheim-Chester disease.
Computer navigation proved to be very helpful during the second total knee arthroplasty in our patient, as it facilitated the orientation of the osseous cuts while avoiding the difficult drilling of the femoral canal, but it required an additional twenty minutes of surgical time.
This report is limited to the presentation of technical considerations at the time of knee replacement surgery as no long-term follow-up results can be provided. We believe that the specifics of the case may be useful information for those providing surgical treatment of similar cases.