Treatment of femoral lengthening-related knee stiffness with a novel quadricepsplasty.

BACKGROUND: Knee stiffness is common after femoral lengthening. Certain patients require a quadricepsplasty when therapy does not improve flexion. A small subset of such patients may also have obligate patellar dislocation with knee flexion due to contracture of the extensor mechanism. We describe our surgical approach for both clinical situations and our outcomes in a pediatric population. METHODS: Six patients, 2 with obligate patellar dislocation, were reviewed (9% of our femoral lengthening population). Indications for surgery included persistent symptomatic restriction of flexion after at least 3 months of therapy or obligate lateral patellar dislocation with knee flexion. Knee range of motion and clinical strength were assessed. Four patients were available for gait analysis and concentric quadriceps strength testing by isokinetic dynamometer. Patient satisfaction was surveyed by questionnaire. RESULTS: All patients had full flexion before lengthening. The mean length gained (by circular external fixation and/or intramedullary motorized nail) was 10.7 cm. The mean age at the time of quadricepsplasty was 16 years. The average active flexion preoperatively was only 48 degrees. Two patients with obligate patellar dislocation and relatively good knee flexion inflated the average preoperative knee flexion. Although both had knee flexion to 100 degrees, the patella dislocated with flexion beyond 30 degrees. At follow-up (mean, 6.2 y) active flexion averaged 120 degrees (P<0.004). All patients had 5/5 clinical strength and no significant quadriceps lag. No patients had patellar instability postoperatively. Isokinetic dynamometer revealed an average weakness of 63% compared with the nonoperative quadriceps. Gait analysis indicated patients had near-normal gait patterns. All patients were satisfied and would pursue the same treatment. CONCLUSIONS: Our quadricepsplasty can significantly increase knee flexion and treat obligate patellar dislocation in the setting of extension contracture after femoral lengthening when nonoperative measures fail. LEVEL OF EVIDENCE: Level IV.

Treatment of adolescents with a periacetabular osteotomy after previous pelvic surgery.

BACKGROUND: Although the success of the Bernese periacetabular osteotomy (PAO) has been reported for primary dysplasia, there is no study analyzing the radiographic, functional, and gait results of the PAO to correct residual hip dysplasia after previous pelvic surgery. QUESTIONS/PURPOSES: We assessed (1) radiographic and (2) functional and gait outcomes of patients treated with a PAO after previous pelvic surgery (PPSx) and compared their results with results of patients with no previous surgery (NPSx) to determine whether the PAO was equally effective in patients with revision pelvic surgery. METHODS: Twenty-nine dysplastic hips in 26 patients (average age, 16.3 years) were included: 13 in the PPSx group and 13 in the NPSx group. Radiographic parameters included the lateral center-edge angle, acetabular index, and femoral head extrusion index measured preoperatively and at 6 months and 1 year. We assessed preoperative and postoperative function using the Harris hip score (HHS). Preoperative and postoperative gait analysis included the hip abductor impulse. RESULTS: Improvements in groups were seen from preoperatively to 1 year postoperatively for the lateral center-edge angle, acetabular index, and femoral head extrusion index without differences between groups. The modified HHSs improved at 6 months and were maintained at 1 year for patients in both groups without differences between groups. The hip abductor impulse returned to preoperative values at 6 months in the NPSx group but not until 1 year in the PPSx group. CONCLUSIONS: The Bernese PAO is effective in providing similar final radiographic and functional results, however, a trend toward decreased hip flexion and abduction power at 1 year was seen with previous pelvic surgery.

Functional results after surgical treatment for congenital knee dislocation.

BACKGROUND: Congenital knee dislocation (CDK) is a rare congenital deformity, which often requires surgery for treatment. Little objective data exist characterizing the outcome of patients who require operative treatment for this condition. The purposes of this study were to objectively evaluate the functional, clinical, and gait outcomes of patients who underwent surgical treatment of CDK; and compare the results of outcome between 2 surgical approaches for this condition: quadricepsplasty and femoral shortening. METHODS: We performed a retrospective review of all patients (7) treated surgically for CDK. Patients were evaluated at an average follow-up of 12+6 years. Each patient underwent a clinical examination, functional evaluation using the Lysholm Knee Questionnaire and Pediatric Outcomes Data Collection Instrument, and a 3-dimensional gait evaluation. The results of the total group were compared with normal controls. Additionally, results of the patients treated with quadricepsplasty were compared with patients treated with femoral shortening. RESULTS: Total knee range of motion for the entire group averaged 112 degrees, with 8 of the 9 knees having flexion>90 degrees. Seven of the 9 knees were found to have some degree of instability on examination, yet none of the patients reported using any form of brace for ambulation. Functional evaluation showed good knee specific and overall function, comparable to normal controls. There were no differences in clinical or functional outcomes between the 2 surgical approaches. Gait analysis revealed a stiff-knee gait pattern to the congenital knee dislocation group, as compared with normal controls, and subtle differences in knee function between the surgical approaches. CONCLUSIONS: The function of patients after surgical treatment for CDK seems to be quite good compared with normal controls. Good knee specific and overall function scores are reported with limitations seen only in higher demand activities. Despite instability of the knee noticed on clinical examination, patients ambulate without braces and have a functional knee range of motion. Little difference in outcome was seen between the 2 surgical approaches used to treat this condition. LEVEL OF EVIDENCE: Therapeutic Study, Level III.

Gait, hip strength and functional outcomes after a Ganz periacetabular osteotomy for adolescent hip dysplasia.

BACKGROUND: The Ganz (Bernese) periacetabular osteotomy was first described for the treatment of adult patients with hip dysplasia; however, it has also been used for adolescent patients. Its effectiveness in improving patients in the short term has not been fully established and no studies, to our knowledge, have analyzed gait and functional outcome in patients with adolescent hip dysplasia. METHODS: An Institutional Review Board-approved prospective study of a consecutive series of patients undergoing a Ganz (Bernese) periacetabular osteotomy for adolescent hip dysplasia was carried out. Standard radiographic parameters were analyzed. Harris hip scores, gait analysis, hip abductor, and flexion strength testing preoperatively and at 6 months and 1 year postoperatively were performed. Statistical analysis compared the 6-month and 1-year data to the preoperative values and a second analysis was performed comparing the patients with hip dysplasia to normative data of similarly aged patients. RESULTS: Twenty-one patients (24 hips) underwent a Ganz periacetabular osteotomy at an average age of 16.1 years for a primary diagnosis of hip dysplasia and pain. There was a significant improvement in all radiographic parameters from preoperation to 1 year in lateral center edge angle (5.5 to 33.0 degrees) (P<0.05), acetabular index of the weight-bearing zone (29.0 to 10.5 degrees) (P<0.05), ventral center edge angle (-1.1 to 32.5 degrees) (P<0.05), and medialization of the joint center relative to the contralateral side (1.12 to 1.05) (P<0.05). Isokinetic abductor strength decreased initially from 62 Nm/kg preoperatively to 58 Nm/kg at 6 months but was improved to 64 Nm/kg at 1 year. Flexion strength decreased from 92 Nm/kg preoperatively to 58 Nm/kg at 6 months but improved to 69 Nm/kg at 1 year. Abductor impulse decreased from 0.26 Nm/kg-s preoperatively to 0.23 Nm/kg-s at 6 months but improved to 0.29 Nm/kg-s at 1 year. Flexion pull-off power decreased from 1.35 Watts/kg to 1.27 Watts/kg and then improved to 1.29 Watts/kg. The Harris hip scores improved from 64.6 at the preoperative evaluation to 74.5 at the 1-year evaluation (Max 89). CONCLUSIONS: The Bernese periacetabular osteotomy is effective in significantly improving radiographic parameters for adolescent hip dysplasia with improvement in functional outcome. Because the osteotomy allows for medialization of the hip joint center and limited abductor muscle dissection the abductor strength improved at follow-up, however, the hip flexion pull-off was decreased. Strategies to improve hip flexion power preoperatively and postoperatively in the future are necessary. LEVEL OF EVIDENCE: Level IV.

Intensity and duration of intermittent exercise and recovery during a soccer match.

Soccer is a sport consisting of high-intensity intermittent exercise, with players making forays across their anaerobic threshold for tactical advantage followed by periods of recovery. The intensity and duration of these work and recovery bouts were defined during a men's soccer match using StepWatch Activity Monitors recording step rate for each 3-second period. The data were coded by custom software to separate work bouts (step rate ≥ 4) from recovery bouts (step rate < 4), and a square wave of the pattern of bouts was plotted for 5 players: center forward, central midfielder, wing midfielder, central defender, and wing defender. Four values were calculated for each work and recovery bout identified: duration, and mean, maximum, and minimum step rate (intensity). This novel technique provided detailed graphical information on the duration and exercise intensity of each position throughout the match. The center midfielder was able to sustain work and recovery bout characteristics throughout the match and appeared to recover at higher intensity levels than other players. The forward showed the consequence of accumulated fatigue late in the match and was unable to sustain the duration of high-intensity work bouts observed earlier in the match. The central defender attenuated the intensity of his work and recovery bouts late in the match staying closer to a more moderate work rate with fewer high- or low-intensity bouts. Having objective data qualifying players' work and recovery bout characteristics might prove valuable for tactical decision making, substitution timing, and for planning future training sessions.

A comparison of multi-segment foot kinematics during level overground and treadmill walking.

Previous work comparing treadmill and overground walking has focused on lower extremity motion and kinetics, with few identified differences. However, a comparison of multi-segment foot kinematics between these conditions has not been previously reported. Sagittal ankle motion using a single rigid body foot model and three-dimensional hindfoot and forefoot kinematics were compared during barefoot, level, overground walking at a self-selected speed and treadmill walking at a similar speed for 20 healthy adults. Slight differences were seen in ankle plantarflexion and hindfoot plantarflexion during first rocker, as well as peak forefoot eversion and abduction, however all changes were less than 3 degrees , and most were within the day-to-day repeatability. These results indicate that foot mechanics as determined using a multi-segment foot model were similar between overground and treadmill walking at similar speeds in healthy adults. Treadmill protocols may provide a controlled method to analyze a patient's ability to adapt to walking at different speeds and surface slopes, which are encountered often during ambulation of daily living.

The effects of surface slope on multi-segment foot kinematics in healthy adults.

Previous work evaluating the effects of surface slope on gait has focused on lower extremity kinematics and kinetics. However, an assessment of multi-segment foot kinematics during walking on inclined and declined ramps has not been previously reported. Sagittal ankle motion using a single rigid body foot model and three-dimensional hindfoot and forefoot kinematics for 24 healthy adults (16 females and 8 males, average age 25.5 ± 4.4 years) were compared during level surface, inclined surfaces of 3%, 6%, 9% and 12% grade and a declined surface of approximately 7.5% grade at a constant speed using a standard treadmill. Significant differences in peak hindfoot plantarflexion, sagittal plane range of motion and time of peak dorsiflexion, plantarflexion, varus and valgus were seen between surface slope conditions. Significant changes were also seen in forefoot plantarflexion and sagittal plane range of motion however the maximum difference between conditions was less than 3°. These results indicate that foot mechanics can be significantly altered when ambulating on ramps in healthy adults. Specifically, treadmill protocols which incorporate different surface slopes often encountered during ambulation of daily living, may provide an improved technique in evaluating a patient's ability to function in the community.

The effects of walking speed on multisegment foot kinematics in adults.

Multisegment foot models provide researchers more-detailed information regarding foot mechanics compared with single rigid body foot models. Previous work has shown that walking speed significantly affects sagittal plane ankle motion. It is important to distinguish changes in intersegment foot mechanics following treatment that are due to clinical intervention versus those due to walking speed alone. Foot and ankle kinematics were collected on 24 adults walking at 5 speeds. Significant differences were seen at the ankle using a single rigid body foot model, as well as at the hindfoot and forefoot using a multisegment foot model, with all motions exhibiting a shift toward plantar flexion and decreased stance time with increasing speed. When evaluating foot mechanics using a multisegment foot model across groups or conducting intrasubject comparison over time/treatments, it is imperative that walking speed be accounted for or controlled.

Effect of sample size and reduced number of principle components on the Gillette Gait Index.

The Gillette Gait Index uses principle components analysis of 16 variables to determine the deviation of an individual's gait compared to a normal control set. Previous literature has not reported on the effects of altering the size of the control set used to create the principle components, or described the effects of using less than the maximum number of principle components, 16, to calculate the Gillette Gait Index (GGI). Calculations of the GGI were determined for a group of 24 able-bodied normal subjects and 24 cerebral palsy subjects using 128 control subjects allotted into 15 subsets of varying sizes, from N=16-128. A minimum of 40 controls were needed for GGI estimates to achieve less than approximately 20% error, and 96 controls were needed for less than 10% error, if all 16 principle components were used. With smaller control sets, an alternative method to increase the accuracy would be to use only those principle components that represent 95% of the variance. Caution must still be used when describing differences in GGI among groups, or changes in an individual's GGI over time. In addition, absolute changes in GGI should always be reported, as differences as great as 150 were seen in cerebral palsy patients across control groups, even when greater than 40 controls are used to create the principle components.