Drop landing analysis of rotational osteotomies.

Pathomechanics resulting from rotational deformities of the long bones in an idiopathic population have not been extensively studied, and are chiefly limited to level over ground walking. Thirty-five adolescents with excessive idiopathic outward tibial torsion (TT), femoral rotation, or both (pan genu) were studied both before and after corrective surgery. Data collected included computational motion analysis of a drop jump and patient-reported outcomes consisting of PODCI and Goal Attainment Scores. Results were compared to an age-matched typically developing cohort (n = 25). Subjects with femoral anteversion (FA) exhibited compensatory hip rotations to normalize knee progression angles at landing. Subjects with only TT did not compensate at the hip, landing with typical knee progression but excessive outward foot progression. These strategies resulted in elevated frontal plane knee moments for FA (P = 0.008), and elevated lateral knee forces in all groups compared to typical, with the TT group reaching significance (P < 0.001). Rotational osteotomies successfully restored elevated kinematics and kinetics to within or below typically developing ranges. Patient-reported outcomes generally improved after surgery across all domains studied. Drop jump testing elucidated compensation strategies employed by these cohorts. Compensation did not fully alleviate elevated forces at the knees. Surgical intervention normalized pathokinematics and pathokinetics, reduced pain, and improved patients' perception of their functional abilities. Greater improvements were found in individuals in the two groups with FA compared to the group with TT only.

Hemiepiphysiodesis for Lower Extremity Coronal Plane Angular Correction in the Distal Femur and Proximal Tibia in Children With Achondroplasia.

BACKGROUND: Achondroplasia is the most prevalent form of skeletal dysplasia, affecting more than 250,000 individuals. Lower extremity angular deformities, particularly genu varum, are common in children with achondroplasia, often resulting in pain and limitation of function. The authors aim to determine the utility of lower extremity growth modulation with hemiepiphysiodesis in children with achondroplasia for correction of coronal plane deformities about the knee. METHODS: The authors performed a retrospective chart review of a single center from 1/1/2000 to 12/31/2020 to identify pediatric patients with achondroplasia treated with hemiepiphysiodesis as their initial procedure at the distal femur and/or proximal tibia. Patients with adequate records and who had completed their treatment were included. Data collected included duration of treatment, complications, need for osteotomy, and radiographic measurements including initial and final mechanical axis deviation, knee mechanical axis zone, mechanical lateral distal femoral angle and medial proximal tibia angle. RESULTS: Ten patients with 17 limbs met our criteria. Nine patients (15 limbs) were treated for genu varum and 1 patient (2 limbs) was treated for genu valgum. Prior to treatment, the mechanical axis fell in zone 3 in 59% of limbs and zone 2 in 41%. Average correction in mechanical axis deviation was 26.1 mm. Average change in mechanical lateral distal femoral angle was 10.3 degrees per limb, and average change in medial proximal tibia angle was 7.1 degrees per limb. Average treatment duration was 909 days. At final follow up, 81% (14/17) of limbs had the mechanical axis in zone 1, with the remaining 18% (3/17) in zone 2. No patient/limb underwent subsequent distal femur or proximal tibia osteotomy for coronal plane alignment. CONCLUSIONS: Children with achondroplasia can successfully be treated with hemiepiphysiodesis to correct coronal plane deformities at the distal femur and proximal tibia. Using this technique, no patient in our series required an osteotomy for genu varum/valgum. LEVEL OF EVIDENCE: Therapeutic level IV, Case series.

Prospective Study on Tension Band Plating: Most Patients are Not Returning to Normal Activities 1 Month Following Surgery.

BACKGROUND: Tension band plating for temporary hemiepiphysiodesis has been reported by several authors as simple and effective for treating angular deformities of the lower limb. Anecdotally, patients have reported higher pain levels than expected given the small size of incision and relatively minimal amount of dissection, and we sought to investigate this further. METHODS: Patients 16 years old or less with lower extremity angular deformities or limb length inequality were prospectively enrolled before tension band plating from 2 pediatric institutions from July 2016 to December 2018. Participants completed postoperative questionnaires regarding their pain and activity level. Pain was assessed using the FACES Pain Scale. Patients were included if they completed the 1 month survey. RESULTS: Of the 48 patients that met inclusion criteria (mean age at surgery: 13.1 y; range: 7 to 16 y), 39 patients completed the survey at 3 months postoperatively. There was a significant change in pain level between 1 week and 1 month postoperatively (P<0.001). Eighty-three percent (34/41) of patients were still taking pain medication at 1 week, which decreased to 38% (18/48) at 1 month. At 3 months, 21% (8/39) patients reported they were still using pain medication. At 1 month, 65% of patients (31/48) had not returned to their prior activity level. Of the 39 patients who played sports, 59% (23/39) still had not fully returned to sports at 1 month. CONCLUSION: At 1 month following tension band plating, 65% of patients had not returned to their preoperative activity level, and 38% were taking pain medications. Although the tension band plate and surgical incision is small in size, patients and parents should be counseled that there are significant activity limitations and pain levels for a month or longer in many patients. LEVEL OF EVIDENCE: Level II.

Cozen's deformity: resolved by guided growth.

Proximal tibial metaphyseal fractures in children can lead to progressive and symptomatic tibial valgus. Corrective osteotomy has been abandoned, due to frequent complications, including recurrent valgus deformity. While spontaneous remodelling has been reported, this is not predictable. For children with persistent deformities, we have resorted to guided growth of the tibia. We present 19 patients who were successfully treated with guided growth, tethering the proximal medial physis. There were ten boys and nine girls, ranging in age from two to 13.6 years at the time of intervention. The mean follow-up from injury was 7.3 years. We documented the intermalleolar distance, mechanical axis deviation (by zone), medial proximal tibial angle (MPTA), and leg length discrepancy. Removal of the plate, or more recently, the metaphyseal screw, was undertaken upon normalization of the mechanical axis. Including the four patients who have undergone repeat tethering for recurrent valgus (one patient-twice), we are effectively reviewing 24 Cozen's phenomena, making this the largest series reported in the literature. Correction of the mechanical axis and the proximal medial tibial angle was achieved in all but one patient. Limb length inequality at follow-up ranged from 0.1 to 1.5 cm, with a mean of 0.5 cm. There have been five recurrences in four patients to date; four corrected with repeat tethering and one is pending. Two patients developed significant over correction because of parental failure to pursue timely follow-up. Both have corrected to neutral with lateral tibial physeal tethering. Ten patients have attained skeletal maturity and required no further treatment. The remaining nine patients will be followed until maturity. Guided growth is an excellent choice for the management of post-traumatic tibial valgus. Our rationale for restricting medial overgrowth is twofold: (1) to restore the MPTA and (2) to reduce the length discrepancy due to tibial overgrowth caused by the fracture. Recognizing the potential for recurrent deformity following implant removal, our standard practice now includes removal of just the metaphyseal screw and subsequent reinsertion, in the event of rebound valgus deformity.Level of evidence Therapeutic IV, retrospective series/no control cohort.

Femoral shaft osteotomy for obligate outward rotation due to SCFE.

Slipped capital femoral epiphysis (SCFE) is an adolescent disease that leads to retroversion of the femoral neck and shaft, relative to the head. Observing that patients with SCFE must walk with an outward foot progression angle and externally rotate the leg in order to flex the hip, we have been performing a femoral shaft rotational osteotomy wherein we rotate the lower femur 45° inward, relative to the upper femur. By correcting retroversion, our goal is to improve functional hip and knee motion, thereby mitigating the effects of SCFE impingement. This is a retrospective review of five hips in four patients (two boys and two girls), average age 14.7 years (range 11 + 7-18 years) who underwent femoral midshaft rotational osteotomy for correction of acquired retroversion of the femur secondary to severe SCFE. We compared clinical findings at the outset to those at an average follow-up of 46 months (range 24-74 months). Pre- and post-gait analysis was performed in three patients. Two of the patients underwent elective arthroscopic osteochondroplasty to alleviate residual FAI: contralateral arthroscopy is pending in one. The first patient in this series received a hip arthroplasty, 62 months after his osteotomy, at age 23. Following midshaft osteotomy, all patients experienced improvement in comfort, gait and activities of daily living. With the patella neutral, they had improved range of hip flexion from an average preoperative flexion of <25° to a postoperative flexion of >90°. Two patients (both male) had delayed union and some loss of correction, secondary to broken interlocking screws; each healed with reamed, exchange nailing. The interlocking screws have since been redesigned and enlarged. Femoral shaft rotational osteotomy restores the functional range of hip motion, while correcting obligate out-toeing and improving knee kinematics. This procedure is technically straightforward, permitting progressive weight bearing, while avoiding the risk of AVN. Osteochondroplasty for residual FAI can be deferred, pending the outcome. Level of evidence III: retrospective series-no controls.

The role of guided growth as it relates to limb lengthening.

For decades, the classic indication for limb lengthening has been reserved for anisomelia that was expected to reach or exceed 5 cm at maturity. Epiphysiodesis was reserved for discrepancies in the 2-5 cm range. With the increasing sophistication of fixators, including rail, hexapod, and hybrid, complex deformities may be corrected simultaneously while moderate to extreme lengthening is achieved. More recently, iterations of telescoping intramedullary rods have further strengthened our armamentarium. Meanwhile, permanent epiphysiodesis techniques, both open and percutaneous, have yielded to more versatile and reversible tethering of one (angle) or both (length) sides of a physis. While the techniques of guided growth and callotasis seem to be diametrically opposed, they may be used in a tandem or complementary fashion, for the benefit of the patient. If treatment is undertaken during skeletal growth, one must be aware that issues remain regarding the accurate assessment of skeletal maturity and prediction of the ultimate outcome. Therefore, there is potential for over- or undercorrection. Reversible and serial guided growth now enable the surgeon to commence intervention at a comparatively young age, for the purpose of optimizing limb alignment and reducing the ultimate discrepancy. Frame application may be delayed or, in some cases, avoided altogether. With the limb properly aligned at the outset of lengthening, elective use of a telescoping intramedullary nail may now be favored over a frame accordingly.

Biomechanical changes associated with femoral derotational osteotomy.

Torsional deformities of the femur in children may occur as a result of either idiopathic or neuromuscular disorders and may be corrected with derotational osteotomies. Regardless of the underlying etiology, neither the effects of the torsional pathologies nor the alterations resulting from corrective osteotomies are well understood. A study of children with isolated femoral anteversion undergoing a single corrective procedure may assist in understanding the biomechanics of the pathology and the efficacy of surgical correction. A multicenter retrospective study included 25 subjects with idiopathic femoral anteversion who underwent femoral derotational osteotomy and had completed pre and postoperative gait analyses. Both changes with surgery and comparisons to typically developing controls were analyzed. Reduced gait pathology and expected improvements in hip rotation and foot progression were found with derotational osteotomy. Overall gait pathology and pathological differences in pelvic tilt, hip flexion moment and knee adduction moment were found comparing anteversion subjects with typically developing subjects. Following surgery, only hip rotation was significantly and clinically different from typically developing subjects, changing from relatively inward to outward. Idiopathic femoral anteversion creates multifaceted and significant alterations to normal gait and should not be considered solely a cosmetic issue. Additionally, the efficacy of derotational osteotomy is illustrated and may be more broadly applied to other conditions where pathologic femoral anteversion is present.

Percutaneous rotational osteotomy of the femur utilizing an intramedullary rod.

The purpose is to describe the technique and report the results and complications of percutaneous femoral rotational osteotomy, secured with a trochanteric-entry, locked intramedullary rod, in adolescents with femoral anteversion. Our series comprised an IRB approved, retrospective, consecutive series of 85 osteotomies (57 patients), followed to implant removal. The average age at surgery was 13.3 years (range 8.8-18.3) with a female-to-male ratio of 2.8:1. The minimum follow-up was 2 years. Eighty-three osteotomies healed primarily. Two patients, subsequently found to have vitamin D deficiency, broke screws and developed nonunions; both healed after repeat reaming and rod exchange and vitamin supplementation. Preoperative symptoms, including in-toeing gait, tripping and anterior knee pain or patellar instability, were resolved consistently. We did not observe significant growth disturbance or osteonecrosis. We noted a 12.5 % incidence of broken interlocking screws; this did not affect the correction or outcome except for the two patients mentioned above. This prompted a switch from a standard screw (core diameter = 3 mm) to a threaded bolt (core diameter = 3.7 mm). These results have led this technique to replace the use of plates or blade plates for rotational osteotomies.

Prospective comparison of subtalar arthroereisis with lateral column lengthening for painful flatfeet.

We prospectively compared subtalar arthroereisis with lateral column calcaneal lengthening for the treatment of painful flatfeet. Twenty-four feet (mean age of patients 12.8 years) were treated. Kinematic motion analysis, pedobarometry, and radiography were performed, and the Oxford Ankle-Foot Questionnaire for Children was administered for each patient before surgery and at the 1-year follow-up. We found statistically significant improvements in both groups, with no difference in their outcomes. Both groups showed significantly improved hindfoot and midfoot motion and positioning. Hindfoot range of motion was preserved. Radiography and pedobarometry also revealed significant improvements. Subtalar arthroereisis is a valid and potentially less-invasive alternative to lateral column lengthening that merits further investigation.

Guided growth of the trochanteric apophysis combined with soft tissue release for Legg-Calve-Perthes disease.

During the initial fragmentation stage of Perthes disease, the principle focus is to achieve containment of the femoral head within the acetabulum. Whether by bracing, abduction casts, femoral and/or pelvic osteotomy, the goals are to maximize the range of hip motion and to avoid incongruity, hoping to avert subsequent femoro-acetabular impingement or hinge abduction. A more subtle and insidious manifestation of the disease relates to growth disturbance involving the femoral neck. We have chosen to tether the greater trochanteric physis, combined with a medial soft tissue release, as part of our non-osteotomy management strategy for select children with progressive symptomatology and related radiographic changes. In addition to providing containment, we feel that this strategy addresses potential long-range issues pertaining to limb length and abductor mechanics, while avoiding iatrogenic varus deformity caused by osteotomy. This is a retrospective review of 12 patients (nine boys, three girls), average age 7.3 years old (range 5.3-9.7), who underwent non-osteotomy surgery for Perthes disease. An eight-plate was applied to the greater trochanteric apophysis at the time of arthrogram, open adductor and iliopsoas tenotomy, and Petrie cast application. We compared clinical and radiographic findings at the outset to those at an average follow-up of 49 months (range 14-78 months). Six plates were subsequently removed; the others remain in situ. Eleven of twelve patients experienced improvement in pain, and alleviation of limp and Trendelenburg sign at latest follow-up. The majority had improved or maintained range of motion and prevention of trochanteric impingement demonstrated by near normalization of abduction. Neck-shaft angles, Shenton's line, extrusion index, center edge angles and trochanteric height did not change significantly. One patient underwent subsequent trochanteric distalization and no other patients have undergone subsequent femoral or periacetabular osteotomies. Leg length discrepancy worsened in four patients and was treated with contralateral eight-plate distal femoral epiphysiodesis. As a group the mean leg length discrepancy did not change significantly. There were no perioperative complications. six trochanteric plates were subsequently removed after an average of 43.7 months (range 28-69) due to irritation of hardware; the others remain in situ, pending further growth. We employed open adductor and iliopsoas tenotomy and Petrie cast application and guided growth of the greater trochanter as a means of redirecting the growth of the common proximal femoral chondroepiphysis. The accrued benefits of preventing relative trochanteric overgrowth with a flexible tether are the avoidance of iatrogenic varus and weakening of the hip abductors. The goals are to preserve abductor strength and avoid trochanteric transfer or intertrochanteric osteotomy.

Success of torsional correction surgery after failed surgeries for patellofemoral pain and instability.

Torsional deformities of the femur and/or tibia often go unrecognized in adolescents and adults who present with anterior knee pain, and patellar maltracking or instability. While open and arthroscopic surgical techniques have evolved to address these problems, unrecognized torsion may compromise the outcomes of these procedures. We collected a group of 16 consecutive patients (23 knees), with mean age of 17, who had undergone knee surgery before torsion was recognized and subsequently treated by means of rotational osteotomy of the tibia and/or femur. By follow-up questionnaire, we sought to determine the role of rotational correction at mean 59-month follow-up. We reasoned that, by correcting torsional alignment, we might be able to optimize long-term outcomes and avert repeated knee surgery. Knee pain was significantly improved after torsional treatment (mean 8.6 pre-op vs. 3.3 post-op, p < 0.001), while 70 % of patients did have some continued knee pain postoperatively. Only 43 % of patients had continued patellar instability, and 57 % could trust their knee after surgery. Activity level remained the same or increased in 78 % of patients after torsional treatment. Excluding planned rod removal, subsequent knee surgery for continued anterior knee pain was undertaken on only 3 knees in 2 patients. We believe that malrotation of the lower limb not only raises the propensity for anterior knee symptoms, but is also a under-recognized etiology in the failure of surgeries for anterior knee pain and patellar instability. Addressing rotational abnormalities in the index surgery yields better clinical outcomes than osteotomies performed after other prior knee surgeries.

Supramalleolar osteotomy: a comparison of fixation methods.

BACKGROUND: For children with persistent tibial torsion, a wide variety of osteotomies and fixation methods have been proposed. We set out to compare the outcomes of percutaneous pin fixation versus a plate and screw construct. Our hypothesis was that the pin fixation group would have comparable outcomes without the need for a secondary procedure for implant removal. METHODS: A retrospective chart review was performed. Data were evaluated on patients undergoing a rotational supramalleolar osteotomy over a 10-year span with follow-up to union. Patient's age, underlying condition, degree of torsion, length of procedure, length of hospital stay, concomitant procedures, complications, recurrence, and secondary procedures were recorded. Statistical analysis utilized the Mann-Whitney U test for evaluation of independent samples. RESULTS: A total of 125 patients met the selection criteria with 186 tibias operated. Sixty-one cases were bilateral. Pin fixation was performed in 61 patients (87 tibias) and plate fixation in 64 patients (99 tibias). Age ranged from 2.5 to 19.6 (average 10.6) years. Surgical time, length of stay, and recurrence did not demonstrate a statistically significant difference between the pin fixation and the plate fixation groups. Forty-seven patients had secondary surgical procedures for removal of implants, 44 in the plate group and 3 in the pin group. Complications were considered major if they required reoperation or fracture care. In the plate group, 16 patients (12.8%) had complications with 5 major complications. In the pins group 3 patients (2.4%) had complications, which were minor. Recurrence was seen in 4 patients in the pin group and 2 patients in the plate group. Recurrence correlated with underlying neuromuscular disease and age younger than 11 years at the time of surgery. CONCLUSIONS: The numbers of complications, both major and minor, were significantly greater in the plate group. Therefore, the results of this study did not support our hypothesis that percutaneous pin fixation of supramalleolar osteotomies would have comparable outcomes to plate and screw fixation.

Multilevel guided growth for hip and knee varus secondary to chondrodysplasia.

BACKGROUND: Young children with chondrodysplasia may develop multilevel varus deformities that compromise comfort and gait. The classic treatment of performing corrective, staged osteotomies, at each level of deformity, is a daunting prospect that is fraught with potential complications. To avoid this scenario, we have adopted single-event, multilevel surgery, using guided growth to simultaneously address bilateral varus deformities of the knee and hip, with good results. METHODS: Three cousins with Schmid-type metaphyseal dysplasia, presented for treatment of progressive varus deformities. In lieu of osteotomies, we used simultaneous guided growth of the proximal and distal lateral femora and proximal lateral tibiae, while ignoring the distal tibial deformity. The pan-genu 8-plates served to neutralize the mechanical axis while preserving a horizontal knee. The rationale for applying the trochanteric 8-plate was to stabilize the proximal femoral chondroepiphysis, hoping to postpone or avert intertrochanteric osteotomy. The average age at surgery was 28 months, with a range of 19 to 33 months, and follow-up has ranged from 28 to 59 months (average 48 mo). The pan-genu 8-plates were removed after an average of 12 months, leaving the trochanteric implants in situ, pending further growth. RESULTS: Neutralization of the mechanical axis resolved lateral knee thrust and intoeing. As the femur is effectively adducted by knee realignment, the greater trochanteric impingement on the ilium is alleviated. Lateral tethering of the trochanteric apophysis served to increase the femoral neck-shaft angle, improving the abductor lever arm. Each patient experienced complete resolution of the fatigue hip pain and Trendelenburg gait. As knee alignment was restored, the ankle varus resolved spontaneously, requiring no direct treatment. The clinical improvement was reflected in trending of the radiographic angles and axes toward normal. CONCLUSIONS: These children have benefited from outpatient guided growth, rather than the anticipated osteotomies, to correct multilevel varus deformities. Our goal is to exclusively use guided growth, repeatedly as needed, to avoid osteotomies altogether. Annual follow-up until skeletal maturity is planned. LEVEL OF EVIDENCE: Level IV-retrospective case series.

Guided growth for ankle valgus.

BACKGROUND: Ankle valgus may be insidious and common in a variety of congenital conditions including clubfoot, neuromuscular disorders and others or acquired after fracture, osteotomies, or other manipulations of the lower extremity. This can cause hindfoot pronaton, resulting in lateral impingement and excessive shoe wear. Orthoses do not change the natural history. Medial hemiepiphysiodesis of the tibia is an accepted method of correcting this problem. Difficulties with transmalleolor screw removal prompted us to adopt the tension band method. Our purpose was to outline the technique of using guided growth with a medial tension band plate and discuss the efficacy of this technique. METHODS: We undertook this retrospective review of 33 patients (57 ankles) who underwent guided growth to correct ankle valgus and were followed until attaining full correction or skeletal maturity. Most of the implants were removed when the ankle was neutral to 5 degrees of varus overcorrection. We obtained weightbearing anteroposterior radiographs of the ankles preoperatively, just before plate removal, and at final follow-up, measuring the lateral distal tibial angle and noting the fibular station. We documented the rate of correction and related complications. RESULTS: The average age at surgery was 10.4 years (range, 6.1 to 14.6 y) and an average follow-up was 27 months (range, 12 to 57.5 mo). The lateral distal tibial angle improved from an average of 78.7 to 90 degrees at implant removal and measured 88.2 degrees at final follow-up. The rate of correction was calculated to be 0.6 degrees per month. The fibular station remained the same in 36 of 57 ankles and improved in 15 ankles. There were 2 cases of skin breakdown complicated by infection. There were no instances of hardware failure, excessive varus, or premature physeal closure and no patient has required an osteotomy. CONCLUSIONS: Without appropriate radiographs, ankle valgus may be mistaken for hindfoot valgus and mismanaged accordingly. Guided growth of the distal medial tibia has become our treatment of choice for ankle valgus in the growing child or adolescent. Use of plate epiphysiodesis is safe, well tolerated, may readily be combined with other treatments, and provides a rate of correction comparable to the transmalleolar screw method. LEVEL OF EVIDENCE: IV, retrospective review, no control series.

Experimental floral and inflorescence trait manipulations affect pollinator preference and function in a hummingbird-pollinated plant.

PREMISE OF THE STUDY: Controversy is ongoing regarding the importance of pollinator-mediated selection as a source of observed patterns of floral diversity. Although increasing evidence exists of pollinator-mediated selection acting on female reproductive success, there is still limited understanding of pollinator-mediated selection on floral traits via male reproductive success. Here we quantify potential selection by the ruby-throated hummingbird, Archilochus colubris, on four floral traits of hermaphroditic Silene exerted through male floral function. METHODS: In single trait manipulative experiments we quantified hummingbird visitation preference and/or fluorescent dye (a pollen analog) donation as a function of number of flowers displayed (inflorescence size), height of the floral display (inflorescence height), floral color, and corolla tube length. KEY RESULTS: Hummingbirds preferred to visit larger floral displays and floral displays at greater height, likely representing a general pollinator preference for larger, more visible signals and/or greater rewards. In addition, hummingbirds preferred to visit red flowers, and male function was greater in flowers manipulated to have longer corolla tubes. CONCLUSIONS: Selection pressures exerted by hummingbirds on S. virginica floral and inflorescence design through male reproductive success are consistent with the contemporary expression of floral traits of S. virginica relative to related Silene species with different pollinators, and they are consistent with the hummingbird syndrome of traits expressed by S. virginica.

Distal tibial rotation osteotomies normalize frontal plane knee moments.

BACKGROUND: Torsional deformities of the lower extremity are common in children and are often corrected with rotational osteotomy. The effects of torsional abnormalities, and the effects of corrective osteotomy, are not well understood. A study of children with isolated idiopathic tibial torsional pathology undergoing a single corrective procedure may assist in understanding the biomechanics of torsional deformities and the effect of surgical correction. METHODS: Preoperative and postoperative gait analyses were performed for eight subjects (eleven sides) with idiopathic excessive inward tibial torsion and ten subjects (fourteen sides) with excessive outward tibial torsion. Sagittal ankle and frontal knee moments were assessed and compared with those for age-matched controls. RESULTS: Preoperatively, subjects exhibited abnormal frontal knee moments at push-off. Subjects with inward tibial torsion demonstrated excessive internal valgus moments, and subjects with outward tibial torsion demonstrated reduced internal valgus or relative internal varus moments compared with the control subjects. Ankle power was significantly reduced in the inward torsion group but not in the outward torsion group. Surgical correction of the torsional deformities normalized frontal plane knee moments in both inward and outward torsion groups and restored ankle power in the inward torsion group. CONCLUSIONS: In the present study, excessive tibial torsion adversely affected frontal knee moments and was associated with other kinematic and kinetic abnormalities. Corrective osteotomies improved all variables studied here and restored many to the values found in the control group.