Proximal Lengthening Research Articles

Distal tibial osteotomy compared to proximal osteotomy for limb lengthening in children.

The aim of this retrospective cohort study was to assess and investigate the safety and efficacy of using a distal tibial osteotomy compared to proximal osteotomy for limb lengthening in children. In this study, there were 59 consecutive tibial lengthening and deformity corrections in 57 children using a circular frame. All were performed or supervised by the senior author between January 2013 and June 2019. A total of 25 who underwent a distal tibial osteotomy were analyzed and compared to a group of 34 who had a standard proximal tibial osteotomy. For each patient, the primary diagnosis, time in frame, complications, and lengthening achieved were recorded. From these data, the frame index was calculated (days/cm) and analyzed. All patients ended their treatment with successful lengthening and deformity correction. The frame index for proximal versus distal osteotomies showed no significant difference, with a mean 48.5 days/cm (30 to 85) and 48.9 days/cm (28 to 81), respectively (p = 0.896). In the proximal osteotomy group, two patients suffered complications (one refracture after frame removal and one failure of regenerate maturation with subsequent valgus deformity) compared to zero in the distal osteotomy group. Two patients in each group sustained obstacles that required intervention (one necessitated guided growth, one fibula lengthening, and two required change of wires). There was a similar number of problems (pin-site infections) in each group. Our data show that distal tibial osteotomies can be safely employed in limb lengthening for children using a circular frame, which has implications in planning a surgical strategy; for example, when treating a tibia with shortening and distal deformity, a second osteotomy for proximal lengthening is not required.Cite this article: Bone Joint J2022;104-B(11):1273-1278.

Intramuscular psoas lengthening at the pelvic brim plus proximal lengthening of the rectus femoris as a treatment for fixed knee flexion deformity in cerebral palsy

Although the correction of knee flexion by lengthening the hamstring musculature is traditionally contemplated in cerebral palsy, literature suggests that treatment of hip flexion also improves knee extension. The aim of the study was to first show the efficacy of the sequence of intrapelvic tenotomy of the psoas followed by intramuscular lengthening of the proximal rectus anterior and, later, that of both surgical soft tissue surgeries separately. For this, a prospective study was carried out in 10 patients with a mean age of 14 years, which presented 16 fixed knee flexes with a mean of deformity of 22°.The data was analyzed through means of an ANOVA of repeated measures and to determine the effect separately of each one of the techniques, the improvements obtained with respect to the previous level were contrasted.The mean extension achieved was 12°, 7° corresponding to the intrapelvic tenotomy of the psoas and, on the remaining knee flexion, a correction of 5° after intramuscular lengthening of the anterior rectus at the proximal level.Both the sequence of proposed gestures and those that form separately, showed statistically significant differences (p < 0.001) in the correction of the deformity.In conclusion, the proposed techniques applied sequentially or separately are effective in reducing knee flexion in predominantly spastic cerebral palsy, facilitating or even being able to avoid the treatment that is directly needed.

Minimally invasive components of the treatment of tibialis posterior insufficiency in adults : Tendoscopy of the Achilles tendon, minimally invasive calcaneus displacement osteotomy and the sinus tarsi spacer

Minimally invasive medializing calcaneal osteotomy, the implantation of atarsi spacer and the tendoscopy of the posterior tibial tendon have been established as treatment options for tibialis posterior insufficiency gradeII. The minimally invasive medializing calcaneal osteotomy allows acorrection of the hindfoot valgus like an open procedure with asignificantly lower risk of wound healing problems. It has gained increasing popularity within recent years. There is also good evidence for arthroereisis, with the use of the sinus tarsi spacer being primarily an addition to calcaneus sliding osteotomy. The possibilities for tendoscopy of the posterior tibial tendon are limited to debridement and synovectomy. Various papers report minimally invasive alternatives to the strayer procedure for ashortened gastrocnemius muscle. The proximal lengthening of the medial head of the gastrocnemius muscle is particularly popular as asoft tissue-sparing, less traumatic procedure. So far, no reports of aminimally invasive cotton osteotomy have been found in the literature.

Synergistic Co-activation Increases the Extent of Mechanical Interaction between Rat Ankle Plantar-Flexors.

Force transmission between rat ankle plantar-flexors has been found for physiological muscle lengths and relative positions, but only with all muscles maximally activated. The aims of this study were to assess intermuscular mechanical interactions between ankle plantar-flexors during (i) fully passive conditions, (ii) excitation of soleus (SO), (iii) excitation of lateral gastrocnemius (LG), and (iv) during co-activation of SO, and LG (SO&LG). We assessed effects of proximal lengthening of LG and plantaris (PL) muscles (i.e., simulating knee extension) on forces exerted at the distal SO tendon (FSO) and on the force difference between the proximal and distal LG+PL tendons (ΔFLG+PL) of the rat. LG+PL lengthening increased FSO to a larger extent (p = 0.017) during LG excitation (0.0026 N/mm) than during fully passive conditions (0.0009 N/mm). Changes in FSO in response to LG+PL lengthening were lower (p = 0.002) during SO only excitation (0.0056 N/mm) than during SO&LG excitation (0.0101 N/mm). LG+PL lengthening changed ΔFLG+PL to a larger extent (p = 0.007) during SO excitation (0.0211 N/mm) than during fully passive conditions (0.0157 N/mm). In contrast, changes in ΔFLG+PL in response to LG+PL lengthening during LG excitation (0.0331 N/mm) were similar (p = 0.161) to that during SO&LG excitation (0.0370 N/mm). In all conditions, changes of FSO were lower than those of ΔFLG+PL. This indicates that muscle forces were transmitted not only between LG+PL and SO, but also between LG+PL and other surrounding structures. In addition, epimuscular myofascial force transmission between rat ankle plantar-flexors was enhanced by muscle activation. However, the magnitude of this interaction was limited.

No functionally relevant mechanical effects of epimuscular myofascial connections between rat ankle plantar flexors.

Triceps surae muscles are mechanically connected by the shared Achilles tendon and by epimuscular myofascial connections. We aimed to assess the effects of proximal lengthening of gastrocnemius and plantaris muscles, imposed by changes in knee angle, on the magnitude and direction of the 3D ankle moment exerted by the soleus muscle and the mechanical interaction between ankle plantar flexor muscles during co-activation of gastrocnemius muscle, in the rat (N=9). Ankle angle was kept constant (90 deg), whereas knee angle was varied between 60 deg and 130 deg. At each knee angle, the soleus muscle was excited individually as well as simultaneously with the gastrocnemius muscle (SO+GA). The mathematical sum of individual soleus and gastrocnemius ankle moments was compared with the ankle moment exerted by SO+GA to assess nonlinear summation. Knee angle did not affect the magnitude of the soleus ankle moment (P=0.695). Moment directions in the transverse (P=0.050) and frontal (P=0.008) planes were affected by knee angle, but dissection indicated that this was not caused by length changes of the two-joint synergistic muscles. Nonlinear summation was found in the magnitude (-1.4 ± 1.9%, mean ± s.d., P<0.001) and in the frontal plane vector direction of the ankle moment (0.13 ± 0.23 deg, P=0.003); however, the extent did not change with knee angle. Although contraction of SO+GA increased the length of the Achilles tendon compared with its length at rest, this was not dependent on the knee angle (P=0.649). Despite the fact that intermuscular force transmission per se cannot be excluded, we conclude that, in vivo, the mechanical effects of epimuscular myofascial connections between rat ankle plantar flexors are not functionally relevant.

Extramuscular myofascial force transmission also occurs between synergistic muscles and antagonistic muscles

The purpose of the present study was to test the hypothesis that myofascial force transmission may not be limited by compartmental boundaries of a muscle group to synergists. Muscles of the anterior tibial compartment in rat hindlimb as well as of the neighbouring peroneal compartment (antagonistic muscles) were excited maximally. Length–force data, based on proximal lengthening, of EDL, as well as distal lengthening of the tibial muscles (TA + EHL) and the peroneal muscle group (PER) were collected independently, while keeping the other two muscle groups at a constant muscle–tendon complex length. Simultaneously measured, distal and proximal EDL active forces were found to differ significantly throughout the experiment. The magnitude of this difference and its sign was affected after proximal lengthening of EDL itself, but also of the tibial muscle complex and of the peroneal muscle complex. Proximal lengthening of EDL predominantly affected its synergistic muscles within the anterior crural compartment (force decrease <4%). Lengthening of either TA or PER caused a decrease in distal EDL isometric force (by 5–6% of initial force). It is concluded also that mechanisms for mechanical intermuscular interaction extend beyond the limits of muscle compartments in the rat hindlimb. Even antagonistic muscles should not be considered fully independent units of muscular function. Particular, strong mechanical interaction was found between antagonistic tibial anterior muscle and peroneal muscle complexes: Lengthening of the peroneal complex caused tibial complex force to decrease by approximately 25%, whereas for the reverse a 30% force decrease was found.

The Proximal Lengthening of Long Flexor Tendon in the Management of Claw Toe Deformities

Purpose : To evaluate the clinical results of acquired claw toe deformities that had been treated with proximal lengthening of the long toe flexor tendons. Materials and Methods : Seventeen patients with a claw toe deformity due to contracture of the long flexor tendons were treated with proximal lengthening of the long toe flexor tendons from January 1993 to January 2003 and were followed up for at least 1 year. The average age at the time of the operation was 42 years and the average follow-up period was 34 months. Achilles tendon lengthening was also performed in 14 cases with an equinus deformity. At the final follow-up, a residual toe deformity, toe pain during walking, patient's satisfaction, and limitation of the shoe-wear were assessed. Results : At the final follow up, all cases showed a complete correction of a claw toe deformity, and did not have callosity at the toe tip or dorsal aspect of the toes. Toe pain during walking was found in 1 case, and a limitation of the shoe-wear was noted in 6 cases. At the final evaluation, 10 cases were graded as excellent, 6 good, and 1 fair. There was no recurrence of the claw toe deformity or limitation of the toe motion. Conclusion : Proximal lengthening of the long toe flexor tendons is recommended for treating flexible claw toe deformities. The procedure produced excellent results regarding the deformity correction and pain relief.

Mechanisms causing effects of muscle position on proximo-distal muscle force differences in extra-muscular myofascial force transmission

Certain recent studies showed that extra-muscular myofascial force transmission affects the length–force characteristics of rat extensor digitorium longus (EDL) muscle significantly after distal or proximal lengthening. This suggested that the relative position of a muscle with respect to its surrounding connective tissues is a co-determinant of muscle force in addition to muscle length, and indicated major effects on muscular mechanics. The specific goal of the present study is to investigate such effects by studying: (1) distributions of lengths of sarcomeres within muscle fibres and (2) the relative contributions of muscle fibres and the extra-cellular matrix to muscle total force, using a finite element model. The length of the muscle modelled was kept constant at a high and at a low muscle length whereas the relative position of the muscle was altered exclusively. For both muscle lengths, the forces exerted at distal and proximal tendons were unequal at almost all muscle relative positions. The proximo-distal force difference was enhanced as the muscle was repositioned away from its reference position. This confirmed the role of relative position of a muscle as a co-determinant of muscle force. At higher muscle lengths, distributions of lengths of sarcomeres arranged in series within muscle fibres were substantial. The force transmitted by the muscles’ extra-cellular matrix comprised a sizable part of muscle total force. At lower muscle lengths distribution of sarcomere lengths was relatively limited indicating that the extra-cellular matrix is bearing the extra-muscular force. However, minor sarcomere length changes were shown to accumulate to sizable effects on the summed forces exerted by the muscle fibres. In addition, the extra-muscular load was shown to manipulate the force exerted by the extra-cellular matrix. We conclude that the relative position of a muscle has substantial effects on intra-muscular mechanics and the importance of the role of the extra-cellular matrix in determining the proximo-distal force differences is comparable to that of the intra-cellular domain.

Extreme Bone Lengthening Using Distraction Osteogenesis After Trauma

We are reporting herein the result of a 22 cm tibial lengthening after using an acute shortening technique with acute temporary angulation for salvage of a posttraumatic lower limb injury. The patient was referred to our center 2 weeks after a Gustilo IIIB open complex injury to the lower limb that included bone and soft-tissue loss. After surgical debridement, the tibial gap was 22 cm and the soft-tissue defect on the anterior aspect of the calf measured 12 x 20 cm. An acute shortening using a 50 degrees angulation (apex posteriorly) of the tibia in an Ilizarov frame was done after a full assessment of all reconstructive surgical options. After complete wound healing, a progressive correction of the angulation was done. Bilevel tibial distraction at a rate of 1.75 mm/day restored the original lower limb length. The 22 cm tibial elongation included 17 cm proximal lengthening and 5 cm distal lengthening. The fractures consolidated after 371 days, all wounds had closed, and no signs of osteomyelitis were present. Good aesthetic and functional results were obtained. The patient had no leg discrepancy compared to his normal limb and he returned to his previous occupation as a garage mechanic and to his favorite sport, boxing. To our knowledge, this is the first report in the English literature of tibial lengthening of this magnitude following acute trauma.

Myofascial force transmission: muscle relative position and length determine agonist and synergist muscle force.

Equal proximal and distal lengthening of rat extensor digitorum longus (EDL) were studied. Tibialis anterior, extensor hallucis longus, and EDL were active maximally. The connective tissues around these muscle bellies were left intact. Proximal EDL forces differed from distal forces, indicating myofascial force transmission to structures other than the tendons. Higher EDL distal force was exerted (ratio approximately 118%) after distal than after equal proximal lengthening. For proximal force, the reverse occurred (ratio approximately 157%). Passive EDL force exerted at the lengthened end was 7-10 times the force exerted at the nonlengthened end. While kept at constant length, synergists (tibialis anterior + extensor hallucis longus: active muscle force difference approximately -10%) significantly decreased in force by distal EDL lengthening, but not by proximal EDL lengthening. We conclude that force exerted at the tendon at the lengthened end of a muscle is higher because of the extra load imposed by myofascial force transmission on parts of the muscle belly. This is mediated by changes of the relative position of most parts of the lengthened muscle with respect to neighboring muscles and to compartment connective tissues. As a consequence, muscle relative position is a major codeterminant of muscle force for muscle with connectivity of its belly close to in vivo conditions.

Treatment of distal femoral nonunions by external fixation with simultaneous length and alignment correction

The use of external fixation for management of distal femoral nonunions may minimise some of the problems frequently encountered in these patients. Fifteen patients treated by external fixation for distal femoral nonunions between 1987 and 1997 were reviewed. There were nine males and six females. The average age was 35.4 years (17–53) with an average follow up of 4.6 years (2–8). Nine followed an open fracture, five a closed fracture and one a femoral osteotomy. Five of the cases were infected nonunions. In all cases an internal fixation device was used as the initial method of treatment. All patients had the nonunion site stabilised with an external fixator. In 12 cases the knee joint was crossed with the fixator to further stabilise the fracture site. All patients had some degree of leg length discrepancy or malalignment that required correction. Fourteen cases united. The other patient united following intramedullary nailing. The average time to union was 10.4 months (4–24). The average range of movement was 80° after treatment. Up to 9 cm of lengthening was achieved using the external fixation system (mean 5.0 cm). The mean angular correction was 15°. One patient had persistent pain despite union at the time of the last follow up. The advantages of preservation of soft tissue, immobilisation of the fracture site by crossing the knee joint and the facility for proximal lengthening make external fixation a definite option in the management of distal femoral nonunions.

High frequency distraction improves tissue adaptation during leg lengthening in humans

The present study investigates the effect of distraction frequency on the development of tensile force in the tissues during lengthening. Two patients with bilateral Ilizarov leg lengthening underwent distraction with high frequency in one leg and low frequency in the other. The clinical situation represented a unique model for investigating the effect of distraction frequency, as each individual served as its own control. Both patients had double level lengthening. Distraction frequency at the proximal lengthening zone was 0.25 mm × 4 in the first leg and 1/1440 mm once every minute in the other. Total diurnal distraction at the proximal metaphysis was 1 mm in both legs. In addition, a distal metaphyseal distraction of 0.25 mm × 3 daily was performed on each leg. The tissue's mechanical response was monitored by measuring the tensile force at the proximal osteotomy. Both patients experienced a significant lower level of force during the high frequency lengthening. The lower level of force was concluded to be due to improved soft tissue adaptation, rather than reduced bone regeneration. Accordingly, high distraction frequency was considered favourable to low frequency, and is recommended in large lengthenings where high force levels are expected.

Deformation across the zone of callotasis during loading. Radiostereometric analysis in a patient with achondroplasia

The present study demonstrates that high-resolution radiostereometric analysis (RSA) can be used to assess global longitudinal compressive deformation across the callotasis zone during loading. In an achondroplastic patient operated with bifocal lengthening of the tibia by use of the Ilizarov external fixator, the axial compressive intersegmental strain in the proximal lengthening zone under a load of 71% of body weight was 7.7 mm. The proximal lengthening zone was 51.0 mm, and accordingly the overall linear strain across the callotasis was 15.1%. This large strain value found in distraction osteogenesis 6 weeks after end of distraction is not consistent with classical theory of the magnitude of micromotion needed for adequate stimulation of bone formation in fracture healing. The increased axial displacement did not stimulate bone healing and delayed union was observed. This one single observation does not allow for any conclusions to be drawn about the relationship of strain to fracture healing, but further and refined use of the RSA method will certainly improve our understanding of the role of axial strains in distraction osteogenesis.