NEW 2026 Adult
Reconstructive Surgery
of the Hip and Knee
Self-Assessment Examination
,AAOS 2026 Adult Reconstructive Surgery of the Hip and Knee
Figure 1a Figure 1b
Question 1 of 200
Figures 1a and 1b are the recent radiographs of an 82-year-old man with rheumatoid
arthritis who underwent total knee arthroplasty (TKA) 18 years ago. These radiographs reveal
osteolysis with loosening of the tibial component. Aspiration and laboratory study findings for
infection are negative. During the revision TKA, treatment of tibial bone loss should consist
of
1- filling the tibial defect with methylmethacrylate.
2- revision of the tibial component with porous metal augmentation.
3- reconstruction with iliac crest bone graft.
4- reconstruction with structural allograft.
PREFERRED RESPONSE: 2- revision of the tibial component with porous metal
augmentation.
DISCUSSION
1
,AAOS 2026 Adult Reconstructive Surgery of the Hip and Knee
Video 1 for reference
For severe tibial defects (Anderson Orthopaedic Research Institute [AORI] types 2 and 3),
metaphyseal fixation is necessary to achieve construct fixation during revision TKA.
Metaphyseal fixation may be achieved with cement, structural allograft, or conical metallic
implants. The major concerns regarding structural allograft are graft resorption and mechanical
failure and technical issues related to fashioning the graft and obtaining a good host-allograft
interface. In a systematic review, porous metal cones were associated with a decreased
loosening rate in AORI 2 and 3 defects compared to structural allografts. Metallic trabecular
metal cones and metaphyseal porous coated sleeves provide a stable construct with which to
support the tibial component during revision TKA. Clinical results with these devices include
good metaphyseal fixation for severe tibial bone defects.
Question 2 of 200
Patient-specific instrumentation (PSI) reliably demonstrates which benefit over
conventional intramedullary guidance systems?
1- Lower cost
2- Improved functional outcomes
3- Better coronal alignment
4- Fewer trays
PREFERRED RESPONSE: 4- Fewer trays
2
, AAOS 2026 Adult Reconstructive Surgery of the Hip and Knee
DISCUSSION
Cost is usually increased with PSI because the theoretical decreased number of surgical
trays and shortened surgical time do not offset cost of presurgical imaging and extra cost
associated with the necessary jigs. Studies do not demonstrate a reliable improvement in
functional outcomes or coronal alignment when PSI is compared to standard instrumentation.
Evidence reveals that PSI necessitates fewer trays than standard instrumentation.
Question 3 of 200
When performing a posterior cruciate-substituting total knee revision, trial components are
inserted. The knee comes to full extension but is tight in flexion. The surgeon should consider
1- flexing the femoral component.
2- downsizing the femoral component.
3- downsizing the tibial component thickness.
4- resecting more distal femur.
PREFERRED RESPONSE: 2- downsizing the femoral component.
DISCUSSION
In this scenario, the extension gap is normal and the flexion gap is tight. Increasing the
flexion gap without changing the extension gap can be performed by downsizing the femoral
component or adding posterior slope to the tibia resection. Flexing the femoral component
tightens the flexion gap. Decreasing the tibial component thickness loosens the flexion and
extension gaps. Resecting more distal femur only loosens the extension gap.
3
Reconstructive Surgery
of the Hip and Knee
Self-Assessment Examination
,AAOS 2026 Adult Reconstructive Surgery of the Hip and Knee
Figure 1a Figure 1b
Question 1 of 200
Figures 1a and 1b are the recent radiographs of an 82-year-old man with rheumatoid
arthritis who underwent total knee arthroplasty (TKA) 18 years ago. These radiographs reveal
osteolysis with loosening of the tibial component. Aspiration and laboratory study findings for
infection are negative. During the revision TKA, treatment of tibial bone loss should consist
of
1- filling the tibial defect with methylmethacrylate.
2- revision of the tibial component with porous metal augmentation.
3- reconstruction with iliac crest bone graft.
4- reconstruction with structural allograft.
PREFERRED RESPONSE: 2- revision of the tibial component with porous metal
augmentation.
DISCUSSION
1
,AAOS 2026 Adult Reconstructive Surgery of the Hip and Knee
Video 1 for reference
For severe tibial defects (Anderson Orthopaedic Research Institute [AORI] types 2 and 3),
metaphyseal fixation is necessary to achieve construct fixation during revision TKA.
Metaphyseal fixation may be achieved with cement, structural allograft, or conical metallic
implants. The major concerns regarding structural allograft are graft resorption and mechanical
failure and technical issues related to fashioning the graft and obtaining a good host-allograft
interface. In a systematic review, porous metal cones were associated with a decreased
loosening rate in AORI 2 and 3 defects compared to structural allografts. Metallic trabecular
metal cones and metaphyseal porous coated sleeves provide a stable construct with which to
support the tibial component during revision TKA. Clinical results with these devices include
good metaphyseal fixation for severe tibial bone defects.
Question 2 of 200
Patient-specific instrumentation (PSI) reliably demonstrates which benefit over
conventional intramedullary guidance systems?
1- Lower cost
2- Improved functional outcomes
3- Better coronal alignment
4- Fewer trays
PREFERRED RESPONSE: 4- Fewer trays
2
, AAOS 2026 Adult Reconstructive Surgery of the Hip and Knee
DISCUSSION
Cost is usually increased with PSI because the theoretical decreased number of surgical
trays and shortened surgical time do not offset cost of presurgical imaging and extra cost
associated with the necessary jigs. Studies do not demonstrate a reliable improvement in
functional outcomes or coronal alignment when PSI is compared to standard instrumentation.
Evidence reveals that PSI necessitates fewer trays than standard instrumentation.
Question 3 of 200
When performing a posterior cruciate-substituting total knee revision, trial components are
inserted. The knee comes to full extension but is tight in flexion. The surgeon should consider
1- flexing the femoral component.
2- downsizing the femoral component.
3- downsizing the tibial component thickness.
4- resecting more distal femur.
PREFERRED RESPONSE: 2- downsizing the femoral component.
DISCUSSION
In this scenario, the extension gap is normal and the flexion gap is tight. Increasing the
flexion gap without changing the extension gap can be performed by downsizing the femoral
component or adding posterior slope to the tibia resection. Flexing the femoral component
tightens the flexion gap. Decreasing the tibial component thickness loosens the flexion and
extension gaps. Resecting more distal femur only loosens the extension gap.
3
