ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION IN ≤21 YEAR OLDS: PATELLAR VERSUS HAMSTRING TENDON AUTOGRAFTS

Abstract

Background:

Bone-patellar tendon-bone (BTB) and hamstring tendon (HS) are commonly used grafts for anterior cruciate ligament reconstruction (ACLR). The optimal graft choice for ACLR remains unclear. We evaluated clinical and self-reported outcomes of patients who underwent ACLR with use of a BTB autograft or double-bundle HS autograft/allograft-augmented HS autograft (HS hybrid).

Hypothesis/Purpose:

No significant differences in outcomes exist between graft choices.

Methods:

Retrospective review of prospectively collected data from patients aged ≤21 years who underwent primary ACLR with BTB or HS autograft/hybrid by one fellowship-trained orthopaedic surgeon and a minimum of 6 months follow-up. Demographics, injury characteristics, concomitant injuries, surgical and radiographic parameters were recorded. Clinical and patient self-reported outcomes (Tegner-Lysholm, pediIKDC, KOOSChild) were compared at 6-months, 1-year and latest follow-up.

Results:

A total of 109 subjects were included; 59 had a HS graft (55 HS autograft, 4 HS hybrid) and 50 a BTB autograft. Patients were between 13 and 21 years old at ACLR and had a follow-up of 1.5 ±1 year. Baseline comparison of demographic, injury and surgical parameters is presented in Table1.1.

Graft rupture occurred in 10 patients (9.2%; 9 males and 1 female) at an average of 2 years after initial ACLR; 8 graft ruptures occurred in the HS group (13.6%, none in HS hybrids) and 2 in the BTB group (4%) (p=0.105). Parameters increasing the likelihood of a re-tear were older age at ACLR (HR: 2.348, p<0.005), a >1-year delay to surgery (HR: 4.105, p=0.048) and a concomitant chondral injury (HR: 5.476, p=0.038) (Cox proportional hazards model, Table1.2).

Arthrofibrosis developed in 4 BTB patients (8%) at an average of 6 months after initial ACLR, but not in HS patients (p=0.041). At most recent follow-up, patellofemoral pain was present in 15 (28%) HS and 5 (10%) BTB patients (p=0.027) and a contralateral ACL tear had occurred in 4 patients (3.7%). No differences were seen between graft groups for knee range of motion, Lachman testing, leg raise, ligament stability and subjective scores - Tegner-Lysholm, pediIKDC, KOOSChild (p>0.05 for each comparison at 6-months, 1-year and most recent follow-up).

Conclusion:

In patients <21 years undergoing ACLR, BTB autograft lead to fewer graft ruptures, however, was associated with a higher rate of arthrofibrosis. Older age at surgery, a delay to surgery and chondral injuries increased the likelihood of re-tear. However, failure rates were low, and we observed no differences between graft types in terms of laxity and patient self-reported outcomes.

Tables/Figures:
Table 1.

Demographics HS, N=59 BTB, N=50 P-Value

Gender, Female 23 (39%) 22 (44%) 0.697

Age at Surgery, years 16.7 ± 1.61 16.5 ± 1.33, 0.382

BMI 25.2 ± 4.0 26.9 ± 5.3 0.146

Follow-up time, years 1.84 ± 1.19, range 0.5-4.8 1.11 ± 0.70, range 0.5-4.21 <0.005

Injury Parameters

Time Injury to Surgery, years 0.41 ± 0.34, range 0.07-1.65 0.52 ± 0.52, range 0.09-2.52 0.477

Laterality, Right 33 (56%) 25 (50%) 0.568

Meniscus tear, yes 35 (59%) 40 (80%) 0.024

Chondral Injury, yes 22 (37%) 16 (32%) 0.687

Surgical Parameters

Graft Size, mm 8.6 ± 0.62, range 8-10 10 ± 0.1, range 9.5-10 <0.005

Fem. Tunnel Diameter, mm 8.6 ± 0.6 10 ± 0 <0.005

Femoral Tunnel Depth, mm 29.9 ± 4.2 27.8 ± 1.2 0.014

Tibial Guide Angle, ° 55.2 ± 1.0, range 55-60 58.1 ± 2.7, range 50-65 <0.005

Tibial Tunnel Diameter, mm 8.6 ± 0.6 10 ± 0.1 <0.005

Meniscus surgery 0.050

None 25 (42.4%) 10 (20%)

Meniscectomy 12 (20.3%) 15 (30%)

Repair 22 (37.3%) 25 (50%)

Chondroplasty, yes 6 (10%) 9 (18%) 0.274

Notchplasty, yes 7 (12%) 7 (14%) 0.782

Radiographic parameters

Femoral Tunnel Angle, ° 34.6 ± 6.3 31.7 ± 8.3 0.064

Tibial Tunnel Angle, ° 64.8 ± 7.3 68.4 ± 7.3 0.011

PDFA, ° 87.3 ± 3.7 86.9 ± 4.2 0.582

Data are presented as Mean ± SD or N (%) Differences in demographic, injury, surgery and radiographic parameters between the two graft groups were compared using t-tests or Wilcoxon rank-sum tests for con.tinuous variables and chi-square or Fisher’s exact tests for categorical variables

Table 2.
Factors associated with time to graft rupture

Demographics Hazard Ratio 95% CI P-value

Gender, Male 5.888 0.728, 47.63 0.097

Age at Surgery, years 2.348 1.439, 3.831 <0.005

BMI 0.986 0.844, 1.153 0.863

Injury Parameters

Time Injury to Surgery, ref within 0.5 years > 1 year 4.105 1.010,16.69 0.048

Meniscus tear, yes 4.029 0.499, 32.55 0.191

Chondral Injury, yes 5.476 1.102, 27.22 0.038

Surgical Parameters

Graft type, reference HS 0.902 0.176, 4.629 0.902

Graft Size, mm 1.285 0.549, 3.007 0.563

Fem. Tunnel Diameter, mm 1.290 0.550, 3.022 0.558

Femoral Tunnel Depth, mm 0.975 0.824, 1.155 0.771

Tibial Guide Angle, ° 1.176 0.791, 1.748 0.422

Tibial Tunnel Diameter, mm 1.101 0.497, 2.442 0.812

Meniscus surgery, reference none

Meniscectomy 5.366 0.595, 48.41 0.134

Repair 3.590 0.397, 32.48 0.255

Chondroplasty, yes 2.766 0.300, 25.49 0.369

Notchplasty, yes 0.505 0.061, 4.152 0.525

Radiographic Parameters

Femoral Tunnel Angle, ° 0.964 0.865, 1.074 0.504

Tibial Tunnel Angle, ° 1.082 0.980, 1.194 0.120

PDFA, ° 0.871 0.723, 1.048 0.143

Cox proportional hazards models were used to examine associations of demographic, injury, surgery and radiographic factors with time to graft rupture.

Demographics	HS, N=59	BTB, N=50	P-Value
Gender, Female	23 (39%)	22 (44%)	0.697
Age at Surgery, years	16.7 ± 1.61	16.5 ± 1.33,	0.382
BMI	25.2 ± 4.0	26.9 ± 5.3	0.146
Follow-up time, years	1.84 ± 1.19, range 0.5-4.8	1.11 ± 0.70, range 0.5-4.21	<0.005
Injury Parameters
Time Injury to Surgery, years	0.41 ± 0.34, range 0.07-1.65	0.52 ± 0.52, range 0.09-2.52	0.477
Laterality, Right	33 (56%)	25 (50%)	0.568
Meniscus tear, yes	35 (59%)	40 (80%)	0.024
Chondral Injury, yes	22 (37%)	16 (32%)	0.687
Surgical Parameters
Graft Size, mm	8.6 ± 0.62, range 8-10	10 ± 0.1, range 9.5-10	<0.005
Fem. Tunnel Diameter, mm	8.6 ± 0.6	10 ± 0	<0.005
Femoral Tunnel Depth, mm	29.9 ± 4.2	27.8 ± 1.2	0.014
Tibial Guide Angle, °	55.2 ± 1.0, range 55-60	58.1 ± 2.7, range 50-65	<0.005
Tibial Tunnel Diameter, mm	8.6 ± 0.6	10 ± 0.1	<0.005
Meniscus surgery			0.050
None	25 (42.4%)	10 (20%)
Meniscectomy	12 (20.3%)	15 (30%)
Repair	22 (37.3%)	25 (50%)
Chondroplasty, yes	6 (10%)	9 (18%)	0.274
Notchplasty, yes	7 (12%)	7 (14%)	0.782
Radiographic parameters
Femoral Tunnel Angle, °	34.6 ± 6.3	31.7 ± 8.3	0.064
Tibial Tunnel Angle, °	64.8 ± 7.3	68.4 ± 7.3	0.011
PDFA, °	87.3 ± 3.7	86.9 ± 4.2	0.582
Data are presented as Mean ± SD or N (%) Differences in demographic, injury, surgery and radiographic parameters between the two graft groups were compared using t-tests or Wilcoxon rank-sum tests for con.tinuous variables and chi-square or Fisher’s exact tests for categorical variables

Demographics	Hazard Ratio	95% CI	P-value
Gender, Male	5.888	0.728, 47.63	0.097
Age at Surgery, years	2.348	1.439, 3.831	<0.005
BMI	0.986	0.844, 1.153	0.863
Injury Parameters
Time Injury to Surgery, ref within 0.5 years > 1 year	4.105	1.010,16.69	0.048
Meniscus tear, yes	4.029	0.499, 32.55	0.191
Chondral Injury, yes	5.476	1.102, 27.22	0.038
Surgical Parameters
Graft type, reference HS	0.902	0.176, 4.629	0.902
Graft Size, mm	1.285	0.549, 3.007	0.563
Fem. Tunnel Diameter, mm	1.290	0.550, 3.022	0.558
Femoral Tunnel Depth, mm	0.975	0.824, 1.155	0.771
Tibial Guide Angle, °	1.176	0.791, 1.748	0.422
Tibial Tunnel Diameter, mm	1.101	0.497, 2.442	0.812
Meniscus surgery, reference none
Meniscectomy	5.366	0.595, 48.41	0.134
Repair	3.590	0.397, 32.48	0.255
Chondroplasty, yes	2.766	0.300, 25.49	0.369
Notchplasty, yes	0.505	0.061, 4.152	0.525
Radiographic Parameters
Femoral Tunnel Angle, °	0.964	0.865, 1.074	0.504
Tibial Tunnel Angle, °	1.082	0.980, 1.194	0.120
PDFA, °	0.871	0.723, 1.048	0.143
Cox proportional hazards models were used to examine associations of demographic, injury, surgery and radiographic factors with time to graft rupture.