Radiographic parameter-driven decision tree reliably predicts aseptic mechanical failure of compressive osseointegration fixation

Figures & data

Figure 1. Compress components with distal femoral adaptor.

Figure 2. Training and test cohort protocol.

Figure 3. Radiographic parameters used to construct the fast and frugal tree model.

Figure 4. Training cohort FFT.

Figure 5. Test cohort FFT.

A. Immediate postoperative radiograph of distal femoral reconstruction showing the initial length between the top of the spindle sleeve and bottom of anchor plug (Spindle).

B. 1-year postoperative radiograph of the same patient as in A, depicting the loss of length of the Spindle.

C. Immediate postoperative radiograph of distal femoral reconstruction.

D. 1-year postoperative radiograph of the same patient as in Figure 3C, depicting hypertrophy at both the bone–implant interface (BoneInterface) and at the bone–pin interface (BonePins).

Table 1. Training cohort: test–retest intra-rater reliability

	Tester 1		Tester 2		Tester 3		Tester 4		Tester 5		Tester 6		Tester 7		Tester 8
Parametera	ICC	p-value	ICC	p-value	ICC	p-value	ICC	p-value	ICC	p-value	ICC	p-value	ICC	p-value	ICC	p-value
Spindle	0.98	< 0.001	0.89	< 0.001	0.93	< 0.001	0.93	< 0.001	0.92	< 0.001	0.82	< 0.001	0.86	< 0.001	0.45	0.006
Coronal	0.33	0.04	0.25	0.09	0.87	< 0.001	0.74	< 0.001	0.35	0.03	0.03	0.5	0.22	0.1	0.17	0.2
FlexEx	0.36	0.03	0.62	< 0.001	0.91	< 0.001	0.88	< 0.001	0.36	0.02	0.29	0.06	0.22	0.1	0.67	< 0.001
BoneInterface	0.55	0.001	0.52	0.001	0.82	< 0.001	0.48	< 0.001	0.49	0.003	0.14	0.2	0.69	< 0.001	0.42	0.01
OsteolysisInterface	0.31	0.05	0.48	0.003	0.69	< 0.001	0.99	< 0.001	0.31	0.05	0.77	< 0.001	0.99	< 0.001	0.32	0.04
BonePins	0.59	< 0.001	0.78	< 0.001	0.59	< 0.001	0.79	< 0.001	0.67	< 0.001	0.69	< 0.001	0.81	< 0.001	0.65	< 0.001
IMRemodel	0.24	0.10	0.41	0.01	0.57	< 0.001	0.57	< 0.001	0.39	0.02	0.40	0.01	0.61	< 0.001	0.71	< 0.001
BoneCortices	0.86	< 0.001	0.89	< 0.001	0.92	< 0.001	0.86	< 0.001	0.68	< 0.001	0.73	< 0.001	0.63	< 0.001	0.73	< 0.001
SBH	0.74	< 0.001	0.9	< 0.001	0.92	< 0.001	0.92	< 0.001	0.30	0.06	0.64	< 0.001	0.47	0.004	0.54	0.001
MSBH	0.79	< 0.001	0.89	< 0.001	0.94	< 0.001	0.92	< 0.001	0.28	0.07	0.19	0.2	0.47	0.004	0.42	0.01
DeltaBone	0.87	< 0.001	0.85	< 0.001	0.99	< 0.001	0.54	< 0.001	0.86	< 0.001	0.88	< 0.001	0.75	< 0.001	0.52	0.002

a Spindle: distance between the top of the spindle sleeve and the bottom of anchor plug; Coronal: varus/valgus alignment; FlexEx: flexion/extension alignment; BoneInterface: evidence of bone hypertrophy at implant interface; OsteolysisInterface: evidence of bone osteolysis; BonePins: evidence of bone hypertrophy at anchor plug pins; IMRemodel: evidence of intramedullary remodeling; BoneCortices: number of cortices with bone hypertrophy; SBH: score of bone hypertrophy; MSBH: modified score of bone hypertrophy; DeltaBone: difference in bone width.

Table 2. Training cohort: inter-rater reliability

Parameter ^a	ICC	p-value
Spindle	0.81	< 0.001
Coronal	0.34	< 0.001
FlexEx	0.46	< 0.001
BoneInterface	0.54	< 0.001
OsteolysisInterface	0.53	< 0.001
BonePins	0.65	< 0.001
IMRemodel	0.32	< 0.001
BoneCortices	0.68	< 0.001
SBH	0.58	< 0.001
MSBH	0.52	< 0.001
DeltaBone	0.76	< 0.001

a See footnote Table 1.