Six-year-old girl with progressive hip pain, altered gait mechanics after tumor resection
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A 6-year-old girl presented with worsening hip pain and an energy inefficient gait pattern (Figure 1 and video).
She had a history of retroperitoneal neuroblastoma status after resection and chemotherapy between aged 5 months and 1 year with subsequent incomplete paraplegia, bilateral neuromuscular hip dysplasia and bilateral planovalgus deformities and was insensate without motor function distal to the knee bilaterally.
Nonoperative measures including bilateral ankle-foot orthoses, a reverse walker and regular physical therapy provided moderate improvements in her mobility. She underwent bilateral Achilles tendon lengthening at aged 34 months, resulting in some temporary improvement in her gait. Through close follow-up with pediatric orthopedic surgery, she reported progressive hip pain with range of motion and increased need to use her wheelchair.
Image: Alexander C. Hayden, MD; Emmanouil Grigoriou, MD; Samuel N. Schrader, MD
On exam, she walked with bilateral external foot progression angles (Figure 2). Radiographs of her hip and pelvis demonstrated progressive acetabular dysplasia with incongruency, a break in Shenton’s line and migration indices of 81% on the right and 46% on the left (Figure 3). The patient’s preoperative right lower extremity alignment and range of motion were 120° of hip flexion, 45° of internal rotation and 40° of external rotation of the hip, and 60° external foot progression angle. Gait lab analysis revealed severe external foot progression angles and hip flexion dominated by hip adductor activation (video).
What are the best next steps in the management of this patient?
See answer below.
Single-event multilevel surgery for bilateral tibial, femoral and acetabular deformities
Given progressive clinical, physical and radiographic exam findings, the patient was indicated for bilateral femoral derotational osteotomies, bilateral tibial derotational osteotomies and a right triple pelvic periacetabular osteotomy. The present case description will focus on the treatment of the right lower extremity.
Surgical technique
The distal tibia derotational osteotomy was performed first, targeting internal derotation of the foot by 35°. The decision to start with the tibial osteotomy was based on the ability to utilize a sterile thigh tourniquet before performing the proximal femoral osteotomy. The distal tibial physis was marked under fluoroscopy and protected throughout the procedure. An anteromedial plate was selected from a distal tibial locking set (OrthoPediatrics Corp.). An anteromedial incision over the distal third of the tibia was made. The tibia was dissected circumferentially at this level. The plate was provisionally secured on the bone with K-wires and screw holes were predrilled. Two K-wires with 35° angulation between these were placed in such a way that when the osteotomy was made and the K-wires were aligned, 35° of internal rotation was induced. The osteotomy was then performed. The plate was secured proximally, and then distally to the tibia. Clinically, the patient had appropriate anatomical alignment of her tibia (Figure 4). Radiographs revealed a well-compressed osteotomy site (Figures 5a and 5b).
Attention was turned to the femoral derotational osteotomy. A 15° internal derotational osteotomy was planned at the subtrochanteric level so the abductors and vastus lateralis insertion were not violated given the patient’s preoperative muscle weakness. A six-hole locking plate was selected. Circumferential dissection was performed at the level of our osteotomy. Two K-wires were placed at a 15° angle proximally and distally to the plate such that once the osteotomy was created and the K-wires were perfectly aligned, 15° of internal derotation was induced. The osteotomy was then performed. The proximal and the distal ends of the plate were secured with screws. The femoral and tibial osteotomies resulted in excellent limb alignment (Figures 6a and 6b).
Attention was turned to the triple periacetabular osteotomy. There was multidirectional instability of the hip on arthrogram. For that reason, it was determined the patient would benefit from a periacetabular osteotomy. Given her open triradiate cartilage, a Tönnis type triple periacetabular ostetomy was performed. A bikini-type incision 1 cm distal to the iliac crest centered over the anterior superior iliac spine was performed and appropriate exposure was obtained. The ischial osteotomy was performed under fluoroscopy starting medially, then centrally and finally laterally, aiming toward the ischial spine. During this osteotomy, the leg was positioned in extension, abduction and external rotation to avoid injury to the sciatic nerve.
Next, our attention was turned to the superior pubic ramus osteotomy. Circumferential retractor placement of the pubic ramus was secured. A 45° oblique cut along the axis of the pubic ramus was made under fluoroscopic guidance with a straight osteotome.
Finally, the iliac osteotomy was performed. After subperiosteal dissection of the inner and outer tables of the ilium and sciatic notch, the sciatic nerve was protected with rang retractors and a silk tie was passed from medial to lateral under direct visualization to shuttle a Gigli saw lateral to medial as described by Gleeson Rebello, MD, and colleagues. A Kalamchi modification osteotomy was made from the sciatic notch to a point a few millimeters proximal to the anterior superior iliac spine. During this osteotomy, the leg remained in extension, abduction and external rotation to protect the sciatic nerve.
A Schanz pin was inserted in the supra-acetabular area and a Weber bone clamp (Arthrex) was placed around the pubic ramus (Figure 7). The pin and clamp were used to maneuver the fragment into the desired position, medializing the fragment, correcting the acetabular version and improving anterior and lateral coverage. Provisional fixation was achieved with K-wires through the iliac crest into the acetabular fragment. When satisfactory correction was achieved under fluoroscopy, definitive fixation was performed with four long 3.5-mm cortical screws drilled through the iliac crest into the acetabular fragment, as well as a “home-run” screw from the anterior inferior iliac spine toward the sacroiliac joint, with care being taken to remain extra-articular (Figure 8). This achieved excellent fixation.
A final arthrogram was performed. The hip was stable in both flexion-internal rotation and extension-external rotation. Postoperative right hip range of motion was 110° of hip flexion, 35° of internal rotation and 30° of external rotation at the hip in 90° of hip flexion. A 10° external foot progression angle was measured postoperatively. Final clinical photographs of the right lower extremity alignment were obtained and deemed satisfactory. The patient was placed in a short leg cast at neutral ankle dorsiflexion, a long knee immobilizer and an abduction pillow.
Follow-up
The patient was discharged from the hospital after achieving satisfactory pain control and physical therapy goals on postoperative day 3. The patient was kept non-weight-bearing on the right lower extremity. The short leg cast was removed at the 2-week follow-up, and she was placed into a controlled ankle movement boot. Active range of motion while lying in bed was encouraged 2-weeks after surgery.
The patient unfortunately developed a heel pressure injury at the 4-week follow-up despite the family taking significant caution to offload the right heel. Radiographs continued to demonstrate interval healing of the osteotomy sites. Most recent follow-up at 8-weeks demonstrated interval healing of the osteotomy, and the heel ulcer had mostly resolved after continued off-loading therapy. Weight-bearing began at this point, with a gradual return to full weight-bearing anticipated during the course of 4 weeks.
Discussion
Resection of neuroblastoma tumors can be complicated by ischemic spinal cord injury. This case demonstrated a patient with the latter complication, and the consequences sustained by her lower extremity development. Despite decreased sensorimotor function in her lower extremities, she could ambulate on presentation, albeit with altered gait mechanics. Her progressive neuromuscular hip dysplasia, excessive femoral retroversion and tibial external rotation eventually caused pain and decreased activity levels.
Triple pelvic periacetabular osteotomies are indicated in cases of neuromuscular hip dysplasia. This procedure creates osteotomies in the ilium, ischium and pubis, creating a free acetabular fragment that can be reoriented to achieve larger corrections than acetabuloplasties for acetabular dysplasia. Given her comparatively high activity level to other patients with paraplegia, ambulation potential and progressive painful neuromuscular hip displacement, the decision to intervene with a triple pelvic periacetabular osteotomy was made to achieve hip stability, medialize the hip joint center and retain functional gait with as little hip pain as possible.
Derotational osteotomies of the proximal femur and distal tibia were performed in the same surgery to facilitate fewer anesthesia events for the patient and decrease overall recovery time. The patient described in the present case report had undergone serial radiographic follow-up with noted healing and improving clinical status at each follow-up appointment. When the osteotomies on the right lower extremity heal and the patient has returned to her baseline functional and ambulatory status, similar procedures will be performed on the contralateral lower extremity.
Key points:
- Triple pelvic periacetabular osteotomies may be performed on young patients with neuromuscular hip dysplasia to preserve and promote proper hip biomechanics throughout their development by medializing the hip joint center and increasing acetabular coverage. Avoiding proximal femoral varus osteotomies is critical in patients with weakened hip musculature.
- Approaching the patient with multiple complex lower extremity deformities by single-event multilevel surgery facilitates a shorter overall recovery time.
- Extra care must be taken to prevent pressure ulcers in those patients without sensation to the feet.
- References:
- Boglino C, et al. Med Pediatr Oncol. 1999;doi:10.1002/(sici)1096-911x(199905)32:5<349::aid-mpo7>3.0.co;2-p.
- Kalamchi A. J Bone Joint Surg Am. 1982;64:183-187.
- Le Coeur P. Rev Chir Orthop. 1965;51:211-222.
- Lyu X, et al. J Pediatr Orthop B. 2020;doi:10.1097/BPB.0000000000000774.
- Ma N, et al. Medicina (Kaunas). 2023;doi:10.3390/medicina59111922.
- Rebello G, et al. J Pediatr Orthop. 2009;doi:10.1097/BPO.0b013e3181b2b3be.
- Sankar WN. J Pediatr Orthop. 2013;doi:10.1097/BPO.0b013e3182770a71.
- Shadmehr MB, et al. Ann Thorac Surg. 2003;doi:10.1016/s0003-4975(03)00882-8.
- Steel HH. J Bone Joint Surg Am. 1973;55:343-350.
- Tönnis D, et al. J Pediatr Orthop. 1981;doi:10.1097/01241398-198111000-00001.
- Wirries N, et al. Orthopadie (Heidelb). 2022;doi:10.1007/s00132-022-04249-2.
- For more information:
- Alexander C. Hayden, MD; Emmanouil Grigoriou, MD; and Samuel N. Schrader, MD, can be reached at the department of orthopedic surgery at the Mayo Clinic in Rochester, Minnesota. Hayden’s email: hayden.alexander@mayo.edu. Grigoriou’s email: grigoriou.emmanouil@mayo.edu. Schrader’s email: schrader.samuel@mayo.edu.
- Edited by Nicole Rynecki, MD, and Harold I. Salmons, MD. Rynecki is a chief resident in orthopedic surgery at NYU Langone. She will be pursuing a sports medicine fellowship at the Hospital for Special Surgery following residency completion. Salmons is a chief orthopedic surgery resident at the Mayo Clinic. He will be pursuing an adult reconstruction fellowship at the Hospital for Special Surgery following residency completion. For more information on submitting Orthopedics Today Grand Rounds cases, please email orthopedics@healio.com.
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