Resorbable screws versus pins for optimal transplant fixation (SPOT) in anterior cruciate ligament replacement with autologous hamstring grafts: rationale and design of a randomized, controlled, patient and investigator blinded trial [ISRCTN17384369].
BACKGROUND
Ruptures of the anterior cruciate ligament (ACL) are common injuries to the knee joint. Arthroscopic ACL replacement by autologous tendon grafts has established itself as a standard of care. Data from both experimental and observational studies suggest that surgical reconstruction does not fully restore knee stability. Persisting anterior laxity may lead to recurrent episodes of giving-way and cartilage damage. This might at least in part depend on the method of graft fixation in the bony tunnels. Whereas resorbable screws are easy to handle, pins may better preserve graft tension. The objective of this study is to determine whether pinning of ACL grafts reduces residual anterior laxity six months after surgery as compared to screw fixation.


METHODS
SPOT is a randomised, controlled, patient and investigator blinded trial conducted at a single academic institution. Eligible patients are scheduled to arthroscopic ACL repair with triple-stranded hamstring grafts, conducted by a single, experienced surgeon. Intraoperatively, subjects willing to engage in this study will be randomised to transplant tethering with either resorbable screws or resorbable pins. No other changes apply to locally established treatment protocols. Patients and clinical investigators will remain blinded to the assigned fixation method until the six-month follow-up examination. The primary outcome is the side-to-side (repaired to healthy knee) difference in anterior translation as measured by the KT-1000 arthrometer at a defined load (89 N) six months after surgery. A sample size of 54 patients will yield a power of 80% to detect a difference of 1.0 mm +/- standard deviation 1.2 mm at a two-sided alpha of 5% with a t-test for independent samples. Secondary outcomes (generic and disease-specific measures of quality of life, magnetic resonance imaging morphology of transplants and devices) will be handled in an exploratory fashion.


CONCLUSIONS
SPOT aims at showing a reduction in anterior knee laxity after fixing ACL grafts by pins compared to screws.
Stengel
Dirk
D
Department of Orthopaedic and Trauma Surgery, Unfallkrankenhaus Berlin Trauma Center, Warener Str 7, 12683 Berlin, Germany. stengeldirk@aol.com
Matthes
Gerrit
G
Seifert
Julia
J
Tober
Volker
V
Mutze
Sven
S
Rademacher
Grit
G
Ekkernkamp
Axel
A
Bauwens
Kai
K
Wich
Michael
M
Casper
Dirk
D
D020341:Absorbable Implants; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D001182:Arthroscopy; D001858:Bone Nails; D001863:Bone Screws; D050376:Bone-Patellar Tendon-Bone Grafting; D002985:Clinical Protocols; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D008297:Male; D013709:Tendon Transfer / Q000379:methods; D013710:Tendons / Q000637:transplantation*; D016896:Treatment Outcome
Unfallchirurg. 2001 Apr;104(4):312-6
11357697
Am J Sports Med. 1999 Jul-Aug;27(4):444-54
10424213
Am J Sports Med. 2002 Mar-Apr;30(2):214-20
11912091
J Bone Joint Surg Am. 2002 Sep;84-A(9):1503-13
12208905
Am J Sports Med. 2003 Jan-Feb;31(1):2-11
12531750
Am J Sports Med. 2003 Jan-Feb;31(1):12-8
12531751
Am J Sports Med. 2003 Jan-Feb;31(1):19-25
12531752
Am J Sports Med. 2003 Mar-Apr;31(2):174-81
12642249
Am J Sports Med. 1991 Sep-Oct;19(5):478-84
1962713
Am J Sports Med. 1994 Sep-Oct;22(5):659-66
7810790
J Bone Joint Surg Am. 1996 Jun;78(6):814-25
8666598
Am J Sports Med. 1996 Jul-Aug;24(4):504-9
8827311
Am J Sports Med. 1997 Jan-Feb;25(1):99-106
9006702
Chirurg. 1999 Feb;70(2):219-30
10097870
Am J Sports Med. 2001 Sep-Oct;29(5):600-13
11573919