William R. Osebold, M.D., Donald M. Christenson, CPO, Shriners Hospitals for Children, Spokane, Washington

In meningococcemia patients who have required a trans-knee or AK amputation, retaining any length of the contralateral tibia is of crucial importance for function. Even a short residual proximal tibia spells the difference between ambulation and being wheelchair-bound. However, as the following two cases illustrate, retaining even a fragment of proximal tibia may be difficult and complicated for patient, prosthetist, and clinician.

Patient 1 at age 9 months experienced fulminant meningococcemia with shock, DIC with thrombocytopenia, skin breakdown, and recurrent fevers, requiring resuscitation, pressor and ventilator support, and IV antibiotics for enterococcal lower limb infection which required bilateral through-ankle amputations. At age 1 year the legs were secondarily infected, and despite antibiotic treatment the right knee had no functional motion, with no quad function and weak hamstrings, with bilateral recurrent skin breakdown, requiring conversion to a right trans-knee and left BK amputation. There were persistent granulations, eschar formation and scaling of both residual limbs.

At age 2 years 1 month, scanogram revealed femoral lengths to be equal, causing difficulty with the level of the right prosthetic knee in relation to the left knee. But despite this and insecure balance, he ambulated with bilateral prostheses and forearm crutches. He then developed left knee recurvatum and underwent thorough open epiphysiodeses of the left proximal tibia and fibula with C-arm visualization. He resumed ambulation with prostheses and a walker, with a left BK residual limb of 15 cms.

At age 6 years he had good skin coverage but prominence of the distal fibula and persistent, progressive left knee recurvatum. MRI scan revealed the proximal tibial and fibular growth plates to remain open. Therefore, at age 6 years 9 months he underwent percutaneous left proximal and fibular epiphysiodeses. The distal end of the fibula was shortened and greensticked, and its new end placed into a notch in the lateral distal residual tibia. The proximal fibular epiphysis was transferred to the distal end of the residual tibia as a biological cap. He was placed in a spica cast to protect the left residual tibia, and at its removal small areas still needed skin coverage, and granulations were treated with silver nitrate sticks.

He was subsequently fitted with a right AK socket with soft insert liner and endoskeleton with Seattle foot and Silesian belt, and a left endo-skeletal BK prosthesis with soft insert liner and Seattle foot. Due to the long periods without prostheses secondary to the left residual limb problems, he required in-patient rehabilitation. At age 7 years 1 month, he has 100 left knee flexion contracture, 5~ of knee varus, and slight persistent recurvatum.

Patient 2 at age 5 had meningococcemia with fulminant purpura. After 5 lower limb debridement and amputation procedures she was left with a right trans-knee and left BK amputation with a laterally dislocated patella tethered to the overlying skin. (All hand digits except the thumbs were amputated through the middle or distal phalanges.)

At age 6 years 4 months she mobilized in a wheelchair, with a 50° left knee flexion contracture and an open wound granulating over the patella. Both residual limbs had multiple scars, and required Z-plasties of contracting scars for better prosthetic fit. Soft tissue remained meager. She was successfully fitted with a right ischial weight-bearing prosthesis. However, the left BK residual limb was extremely sensitive, with a residual 30° flexion contracture and a prominent distal fibula that would not permit weight-bearing. The hamstrings were tight and there was a sore over the quadriceps tendon.

At age 7 years she underwent excision of 5 cm of the distal fibula and 3.5 cm of irregular osteocartilaginous overgrowth from the distal tibia. A disc from this hypertrophied tissue was placed on the distal end of the residual tibia as a biological cap, and the hamstrings were released. The limb healed slowly with eschar formation and dehiscence with granulations.

At age 7 years 4 months she had left knee recurvatum to counter her flexion contracture, but showed progressive valgus. Despite using silastic prosthesis liners for her fragile skin, and fabricating the BK prosthesis to accommodate her valgus, it was felt that tissue expanders might allow eventual replacement of the patella more centrally. Despite the recurvatum, MRI scan showed no bony bridging across the tibial physis. Despite the lateral left patellar dislocation and rotatory subluxation of the tibia on the femur, she was ambulating well with a walker and a left PTB prosthesis with silicone liner and supracondylar strap, which accommodated her left knee valgus. (On the right knee she wore an AK prosthesis with a 7-bar knee.)

At age 7 years 6 months three tissue expanders were implanted, with 2 medial and 1 lateral soft tissue flap. Two months lateral she had a low-grade infection, and, despite aggressive PT for ROM, had developed a progressive left knee flexion contracture of 48°. Three months after insertion, one expander site had a frank abscess. Despite antibiotics and debridement and exchange of tissue expanders, recurrent infection and breakdown of overlying skin required removal of all 3 expanders.

At age 8 years 2 months, with diligent PT the knee flexion contracture was 20°, valgus was 22°, and the subluxated patella was in a better position. She progressed to new prosthesis, resumed ambulation with forearm crutches, continued to improve left quad strength, and no further operations are planned.

The prodigious challenges in managing the residual BK limbs of both these patients belie the importance of preserving them: both patients had remarked to their mothers that if they lost the short-segment unilateral tibias they would no longer ambulate. Despite the poor soft tissue coverage, repeated skin breakdown, stiffness, and deformity, these nubbins of compromised BK residual limb must be preserved to optimize function for post-meningococcemia patients.

Authors address:

William R. Osbold, M.D.
Shriners Hospital for Children
911 W. 5 th Avenue
Spokane, WA