Table 3. Pre-Operative Data and Predictions for a Hypothetical Subject with Crouch Gait.

Subject has excess tibial torsion and short and slow hamstrings at his first gait visit

First-Visit Variable	Coefficient	Subject Value	Δ Expected Improvement
Strength Score [24]	1.28	0.26	0.333
Ipsilateral Mean Stance Knee Flexion (°)	0.898	38.0	34.1
Contralateral Mean Stance Knee Flexion (°)	−0.235	34.6	−8.13
Gait Deviation Index [29]	−0.136	64.9	−8.83
Mean Pelvic Tilt (°)	−0.213	15.7	−3.34
Knee Flex Vel at Toe-Off (°/% Gait Cycle)	2.54	1.05	2.67
Mean Stance Ankle Dorsiflexion (°)	0.137	10.7	1.47
Prior Tendo-Achilles Lengthening (1/0)	−3.04	YES	−3.04
Planned Patellar Advance/FEO (1/0)*	9.36	NO	0
Planned FDO (1/0)*	3.87	YES	3.87
Triplegic Subtype (1/0)	5.36	NO	0
Quadriplegic Subtype (1/0)	6.11	NO	6.11
Multiple Qualifying Visit Pairs (1/0) †	−5.45	NO	0
Constant	−18.7		−18.7
Expected Improvement without Hamstrings Lengthening or TDO			~6.5°
Expected Improvement with Hamstrings Lengthening and/or TDO			~13°

^*The clinical team has decided to perform a femoral derotation osteotomy for this hypothetical subject, but not a patellar advance.

^†This is the first time the patient has visited the gait lab exhibiting a moderate crouch gait pattern