Evaluation of split tibial tendon transfers in correction of varus foot deformity and prevention of skeletal contractures in patients with spastic cerebral palsy

Abstract

Cerebral palsy (CP) is neurodevelopmental disorder characterized mainly by the motor, movement, and muscle tone abnormalities. Spastic CP if often accompanied by the foot deformities, which can be treated with orthoses, muscle tone management and surgical interventions. Aim. The aim of the thesis was to determine the results of split tibial tendon transfers in patients with spastic varus foot deformity due to CP, and to determine whether surgical outcome depended on other parameters aside from surgical technique, as well as to determine the incidence of postoperative skeletal contractures. Methods. Patients were categorized into four groups depending on the surgical intervention performed. One group was treated with split anterior tibial tendon transfer (SPLATT) procedure; second group of patients was treated with split tendon transfer of tibialis posterior muscle (SPOTT) procedure, the third group was operated with the combination of those two procedures (SPLATT+SPOTT), and the fourth group of patients was treated with the modified SPOTT intervention. Gross motor function was assessed preoperatively by the expanded and revised Gross Motor Function Classification Scale (GMFCS). Functional mobility was assessed before and after the operation using the Functional Mobility Scale (FMS). Postoperative change in FMS was categorized as positive, equal, or negative change in relation to preoperative values. Weight-bearing radiographs were used to determine postoperative valgus/varus foot deformity (<5° - neutral, 5° - 10° - mild, and >10° - severe). Postoperative outcomes were assessed using Hoffer’s clinical criteria in procedures involving tibialis anterior, and by Kling’s clinical criteria for surgical procedures involving tibialis posterior. Results. In 14 patients (16 feet), SPLATT procedure was performed. Preoperative GMFCS level I was recorded in 8 cases (50%), while 5 cases (31.3%) had level II and 3 cases (18.8%) had level III. In the majority of cases (13 cases, 81.2%) there was a positive change in FMS values, while in remaining 3 cases (18.8%) postoperative FMS values remained unchanged. After median follow up of 7 years (IQR 6.24 – 11.00) excellent/good results were achieved in 14 (87.5%) cases, while poor results were obtained in two (12.5%) cases. There was no significant correlation between the surgical outcome and patients’ age at the time of the surgery (ρ=0.136, p=0.615). Postoperative fixed skeletal contracture was recorded in only one patient treated with SPLATT, where triple arthrodesis was performed. Sixty-six patients (76 feet) were treated with SPOTT procedure. The majority of patients had GMFCS level II (36 cases, 47.4%) and level III (34 cases, 44.7%). Positive postoperative change in FMS was noted in 52 (68.4%) cases, while no change was recorded in 24 (31.6%). Median follow-up was 8 years (IQR 6 – 11 years), with good/excellent results obtained in 65 (85.6%) feet, and poor postoperative outcome recorded in 11 (14.5%) feet. There was no statistically significant difference in surgical outcome compared to patients’ gender (χ2=0.773, p=0.514), and no significant correlation with the patients’ age at the time of the surgery (ρ=-0.094, p=0.418)...

Cerebralna paraliza (CP) je neuromišićni poremećaj koji se primarno karakteriše poremećajem motorike i mišićnog tonusa. Spastična forma CP često uključuje poremećaje deformacije stopala koje se mogu lečiti ortozama, kontrolom mišićnog spazama i hirurškim intervencijama. Cilj. Cilj teze je bio određivanje uspešnosti parcijalnih transfera tibijalne tetive kod pacijenata sa spastičnim varusnim deformitetom stopala, i ispitivanje povezanosti ishoda sa drugim parametrima osim same hirurške tehnike, kao i određivanje incidence postoperativnih koštanih kontraktura. Metode. Operisana stopala su klasifikovana u grupe na osnovu hirurškog metoda korekcije deformiteta. Prvu grupu činila su operisana stopala na kojima je obavljena parcijalna transpozicija prednjeg tibijalnog mišića (SPLATT). Drugu grupu činila su stopala na kojima je obavljena parcijalna transpozicija zadnjeg tibijialnog mišića (SPOTT). Treću grupu činila su stopala na kojima su obavljene obe procedure (SPLATT i SPOTT), dok su četvrtu grupu činila stopala na kojima je obavljena modifikacija SPOTT procedure. Procena preoperativnog opšteg motornog statusa učinjena je na osnovu sistema klasifikacije motornih funkcija (engl. expanded and revised Gross Motor Function Classification Scale, (GMFCS)). Ambulatorni status pacijenata pre i nakon operacije procenjivan je na osnovu skale funkcionalne mobilnosti (engl. Functional Mobility Scale, FMS). Postoperativna promena vrednosti FMS je opisana kao pozitivna, nepromenjena ili negativna u odnosu na preoperativne vrednosti. Radiografije stopala u stojećem stavu su korišćene za utvrđivanje postojanja postoperativnog varusnog ili valgusnog deformiteta (manje od 5° - bez deformiteta, od 5° do 10° - blagi deformitet, i preko 10° - izraziti deformitet). Postoperativni ishod je procenjivan na osnovu Hoferovih kliničkih kriterijuma kod procedura vezanih za prednji tibijalni mišić, odnosno na osnovu Klingovih kliničkih kriterijuma kod procedura vezanih za zadnji tibijalni mišić. Rezultati. Kod 14 pacijenata (16 stopala) sprovedena je SPLATT procedura. Kod 8 pacijenata (50%) preoperativni GMFCS je bio nivo I, dok je kod 5 pacijenata (31,3%) bio II, a kod 3 pacijenta (18.8%) je iznosio III. U većini slučajeva (13 stopala, 81,2%) bilo je pozitivne promene u vrednosti FMS, dok su u preostala 3 slučaja (18,8%) postoperativne vrednosti FMS ostale nepromenjene. Nakon prosečnog praćenja od 7 godina (IQR 6,24 – 11,00), odlični/dobri rezultati su postignuti kod 14 (87,5%) stopala, dok su loši rezultati notirani kod dva (12,5%) stopala. Nije uočena značajna korelacija između hirurškog ishoda i uzrasta pacijenta u vreme procedure (ρ=0,136, p=0,615). Postoperativna skeletna kontraktura zabeležena je kod jednog pacijenta nakon SPLATT procedure, koji je lečen triplom artrodezom. Kod 66 pacijenata (76 stopala) primenjena je SPOTT procedura. Većina pacijenata je imala GMFCS nivo II (36 stopala, 47,4%) i III (34 stopala, 44,7%). Pozitivna postoperativna promena u vrednosti FMS registrovana je kod 52 (68,4%) slučaja. Prosečno praćenje pacijenata iznosilo je 8 godina (IQR 6 – 11 godina) sa odličnim/dobrim ishodom kod 65 stopala (85,6%), dok je loš ishod notiran kod 11 (14,5%.) slučajeva. Nije uočena statistički značajna razlika u hirurškom ishodu u odnosu na pol (χ2=0,773, p=0.514) i uzrast pacijenata u vreme hirurške intervencije (ρ=-0,094, p=0,418)...