Improved functional outcome with no decrease in hip strength 2 years following Ganz periacetabular osteotomies for adolescent hip dysplasia

Rehabilitation-Specific Predictors of Pain Intensity and Physical Activity Levels in Individuals With Acetabular Dysplasia 6 Months After Periacetabular Osteotomy

INTRODUCTION

Individuals with acetabular dysplasia often report hip joint instability, pain, and poor hip-related function. Periacetabular osteotomy (PAO) is a surgical procedure that aims to reposition the acetabulum to improve joint congruency and improve pain and function. We aimed to examine the influence of presurgery clinical measures on functional recovery following PAO and the associations among clinical outcomes after PAO.

METHODS

We screened 49 potential participants, 28 were enrolled, and 23 completed both study visits (pre-PAO and 6 months post-PAO). We evaluated dynamometer-measured hip and thigh strength, loading patterns during a squat and countermovement jump (CMJ), pain intensity, and device-measured physical activity (PA) levels (light, moderate-to-vigorous PA [MVPA], and daily steps). We used linear regression models to examine the influence of muscle strength (peak torque; limb symmetry index [LSI]) and loading patterns before PAO on pain intensity and PA levels in individuals 6 months following PAO. Additionally, we used Pearson correlation coefficient to examine cross-sectional associations among all variables 6 months following PAO.

RESULTS

Lower extremity muscle strength and loading patterns during the squat and CMJ before PAO did not predict pain intensity or device-measured PA levels in individuals 6 months following PAO (p > 0.05). Six months following PAO, higher knee extensor LSI was associated with higher time spent in MVPA (r = 0.56; p = 0.016), higher hip abductor LSI was associated with both lower pain (r = 0.50; p = 0.036) and higher involved limb loading during the squat task (r = 0.59; p = 0.010). Lastly, higher hip flexor LSI was associated with higher CMJ takeoff involved limb loading (r = 0.52; p = 0.021) and higher involved hip extensor strength was associated with higher CMJ landing involved limb loading (r = 0.56; p = 0.012).

CONCLUSION

Six months after PAO, higher hip and thigh muscle strength and strength symmetry were associated with lower pain, higher PA levels, and greater normalized limb loading during dynamic movement tasks.

Physical impairments in Adults with Developmental Dysplasia of the Hip (DDH) undergoing Periacetabular osteotomy (PAO): A Systematic Review and Meta-Analysis

Background

Developmental dysplasia of the hip (DDH) is a condition associated with hip pain and impairments. Periacetabular osteotomy (PAO) is a common surgical treatment for DDH. Outcomes following PAO have historically been based on radiology or patient reported outcomes, and not physical impairments.

Objective

To investigate differences in physical impairments in adults with DDH undergoing PAO compared with asymptomatic participants, and to investigate pre- to post-PAO changes in physical impairments.

Design

Systematic review with meta-analysis.

Methods

A literature search was performed in five databases (MEDLINE, CINAHL, EMBASE, Sports Discuss, and PsychINFO), using the PRISMA checklist. Studies were considered eligible if patients were aged 15 years and older, treated with PAO for DDH and if they included a physical impairment outcome measure. Two independent reviewers performed data extraction and assessed methodological quality, using a modified version of the Downs and Black checklist.

Results

Of 5,017 studies, 24 studies were included with 2190 patients. The methodological quality scores ranged from 39% to 88%. With low level of evidence, meta-analysis showed 58% of patients had a positive anterior impingement test (95%CI: 39-76%), prior to PAO and one to three years after PAO. Five years after PAO, the proportion fell to 17% (95%CI: 11-24%). Prior to PAO, patients with DDH walked with a lower peak hip extension angle, compared to asymptomatic participants (SMD 0.65 (95%CI 0.21-1.10). Best evidence synthesis of non-pooled data showed limited evidence of increased walking velocity, stride length and improved hip flexion and extension moment 18-months post-PAO compared to pre-op. Cadence, hip abduction and hip flexion strength did not change.

Conclusion

Most patients with DDH have a positive hip impingement test, pre-PAO. Compared to asymptomatic participants, patients with DDH demonstrate physical impairments during walking which appear to improve after surgery. Hip abduction and flexion strength did not change pre- to post-PAO.

Level of Evidence

1b.

Asymmetry in Muscle Strength, Dynamic Balance, and Range of Motion in Adult Symptomatic Hip Dysplasia

Hip dysplasia (HD) is a typical developmental abnormality of the hip joint, and discomfort is often found in adulthood. This study compared patients with symptomatic HD in muscle strength, dynamic balance, and range of motion (ROM) with healthy individuals. Patients included those who complained of unilateral pain although the lateral center edge angle (LCEA) exhibited bilateral abnormality. Participants (n = 95; men: 46, women: 49) were divided into symptomatic and asymptomatic sides, and a healthy group without a history of hip joint disease (n = 70; men: 30, women: 40) was compared. Hip flexion, extension, abduction, and adduction were performed at an angular velocity of 30°/s using an isokinetic strength test device. The Y-balance test was conducted to measure dynamic balance, and ROM was measured using an electronic goniometer to evaluate flexion, extension, adduction, abduction, and internal and external rotations. In addition, the pain visual analog scale (VAS) and hip and groin outcome scale (HAGOS), a subjective evaluation of the hip joint, were evaluated. ROM (flexion, abduction, internal rotation, and external rotation) was significantly decreased in the HD symptomatic sides of men and women compared to those of the healthy group and the asymptomatic side, and the dynamic balance, flexion, and abduction muscle strength were also lower on the symptomatic sides. Although the LCEA of the HD asymptomatic side was lower than that of the healthy group, there were no significant differences in VAS, flexion, extension, abduction ROM, and extension strength compared to those of healthy individuals. In conclusion, patients with HD were mostly bilateral, and on the symptomatic side, there was a decrease in ROM, dynamic balance, and muscle strength; however, on the asymptomatic side, the function was relatively close to normal.

Hip muscle and joint contact forces before, 6 and 12 months after minimally invasive periacetabular osteotomy

BACKGROUND

Previous studies on different periacetabular osteotomy approaches for correction of hip dysplasia disagree on the time course of normalisation of muscle function postoperatively, some stating that especially hip flexor function is not fully normalised after 12 months.

PURPOSE

The purpose of this study was to evaluate hip function during walking before, and 6 and 12 months after minimally invasive periacetabular osteotomy.

METHODS

Using conventional 3D inverse dynamics followed by static optimisation, we calculated hip net joint moment and angular impulse, as well as individual muscle forces and hip joint contact force, during walking for 32 patients with hip dysplasia and 32 matched controls.

RESULTS

None of the extensor and abductor measures were significantly different between controls and patients tested preoperatively, nor between any of the 3 time points patients were tested. For all of the flexor measures, patients' preoperative values were lower than controls', but had increased to values above the controls 6 months postoperatively.

CONCLUSION

Hip muscle function during walking seemed normalised after 6 months after minimally invasive periacetabular osteotomy, while joint contact force did not fully normalise until 12 months postoperatively, perhaps because the hip joint structures need a longer time to heal than the muscles and a potential pain alleviating strategy was still in effect.

TRIAL REGISTRY

Movement pattern in patients with hip dysplasia https://clinicaltrials.gov/ct2/show/NCT01344421, NCT01344421.

Isometric hip strength impairments in patients with hip dysplasia are improved but not normalized 1 year after periacetabular osteotomy: a cohort study of 82 patients

Background and purpose - In patients with hip dysplasia, knowledge of hip muscle strength after periacetabular osteotomy is lacking. We investigated isometric hip muscle strength in patients with hip dysplasia, before and 1 year after periacetabular osteotomy, and compared this with healthy volunteers. Furthermore, we investigated whether pre- to post-surgical changes in self-reported pain and sporting function were associated with changes in isometric hip muscle strength.Patients and methods - Isometric hip muscle strength was assessed twice in 82 patients (11 men) with a mean age of 30 (SD 9) years, before and 1 year after surgery, and once in 50 healthy volunteers. Isometric hip muscle strength was assessed with a hand-held dynamometer. Copenhagen Hip and Groin Outcome Score was used to measure self-reported outcome.Results - Despite 1-year improvements in isometric hip flexion (0.1 Nm/kg; 95% CI 0.06-0.2) and abduction (0.1 Nm/kg; CI 0.02-0.2), the patients' muscle strength was 13-34% lower than the strength of the healthy volunteers both pre- and post-surgery (p < 0.01). Moreover, changes in self-reported pain were associated with changes in hip flexion (13 points per Nm/kg; CI 1-26) and abduction (14 points per Nm/kg; CI 3-25), while changes in self-reported sporting function were associated with changes in hip extension (9 points per Nm/kg; CI 1-18).Interpretation - Isometric hip muscle strength is impaired in symptomatic dysplastic hips measured before periacetabular osteotomy. 1 year after surgery, isometric hip flexion and abduction strength had improved but muscle strength did not reach that of healthy volunteers.

The relationship of coronal trunk motion on the hip abductor moment impulse in pre-operative hip pathology patients during walking

BACKGROUND

Compensatory mechanisms for hip pain, pathology, and weakness include excessive trunk lean towards the stance limb, counteracting pelvic drop to maintain stability during single leg stance. Trunk lean shifts the center of mass towards the hip joint center to decrease the moment arm and reduce hip abductor demand. The purpose of this study was to evaluate whether adolescent patients with symptomatic hip pain demonstrate excessive trunk lean and the effect on the hip abductor moment impulse.

METHODS

Self-selected speed walking data collected through an approved study were reviewed on pre-operative patients clinically diagnosed with a hip deformity. Instrumented motion analysis was performed to analyze trunk kinematics and the hip abductor moment impulse.

FINDINGS

There was a weak, but significant correlation between hip abductor moment impulse and trunk lean. Patients diagnosed with Acetabular Dysplasia demonstrated an increased trunk lean and a decreased hip abductor moment impulse (r = - 0.311, p = 0.001). Of those who presented with excessive trunk lean, 62% of these patients had a normal hip abductor moment impulse. There was no correlation between hip abductor moment impulse and hip abductor strength.

INTERPRETATION

Excessive trunk lean was not seen uniformly across adolescent patients with symptomatic hip deformities, despite pain being reported in 80% of patients. Furthermore, a majority of those that presented with excessive trunk lean did not present with a reduced moment, suggesting that although the amount of lean was greater than normal, it was not enough to significantly reduce the demand on the hip musculature.

Clinically derived biomechanical criteria for the Trendelenburg test

BACKGROUND

The Trendelenburg test has been used to assess hip abductor muscle function. A standardized evaluation of the test requires an assessment of both pelvis and trunk coronal plane alignment as the patient stands on one leg for 30 s. Coronal plane biomechanics using motion analysis allows for development of objective criteria to grade the test response. The aim of this study was to develop biomechanical criteria of the pelvis and trunk coronal plane kinematics.

METHODS

The video of 39 subjects with acetabular hip dysplasia performing the test while instrumented with a full-body modified Plug-In-Gait marker set for three-dimensional kinematic analysis, were evaluated by two orthopedic surgeons and one senior level biomechanist. Reviewers as a group assessed whether the subject had a positive test and noted the reason using guidelines outlined in the literature. Coronal plane trunk and pelvic angles of all subjects were analyzed and Receiver Operating Characteristic curves were used to determine optimal kinematic cutoff values for each positive Trendelenburg test reason.

FINDINGS

There were 26/39 patients who reviewers identified as having a positive test. Area under the curve of the receiver operating characteristic curve for trunk and pelvis mean/minimum were greater than 0.75. The curve was used to identify the optimal cut-offs of trunk lean and pelvic obliquity mean/minimum.

INTERPRETATION

The biomechanical criteria developed includes clinically derived coronal plane kinematic cut-offs of the pelvic and trunk angles. The criteria can be used within a motion capture setting for the standardization of the grading of the test response.

Are changes in pain associated with changes in quality of life and hip function 2 years after periacetabular osteotomy? A follow-up study of 321 patients

Symptomatic hip dysplasia is primarily treated surgically with periacetabular osteotomy (PAO). It is unclear whether changes in quality of life (QoL) and changes in hip function follow the same pattern of improvement as pain following PAO. The aim of the study is to investigate whether changes in pain were associated with changes in QoL and hip function 2 years after PAO. Furthermore, to examine patient satisfaction 2 years after PAO. This is a follow-up study with data from Aarhus University Hospital Denmark. Pain was measured using the Visual Analogue Scale, QoL with Short-Form 36 and hip function with Hip disability and Osteoarthritis Outcome Score both preoperatively and 2 years after PAO in 321 patients. Multiple linear regressions were applied. Significant mean improvements in pain, QoL and hip function were found (P < 0.05). Significant associations between changes in pain and changes in physically related QoL and changes in hip function, respectively were found (P < 0.05). A non-significant association between changes in pain and changes in mentally- related QoL was found (P = 0.13). The majority of patients (84%) reported satisfaction with the result of PAO and would undergo PAO again if they had known the results in advance. The study had a loss to follow-up of 26%. Decreased pain was significantly associated with increased physically related QoL and improved hip function 2 years after PAO. A non-significant association between decreased pain and increased mentally related QoL was found. Patients were in general satisfied with treatment and results 2 years after PAO.

Fracture at the Ischio-Pubic Junction After Periacetabular Osteotomy in the Adolescent Population

INTRODUCTION

The Ganz periacetabular osteotomy (PAO) is a well-accepted surgical intervention for hip dysplasia. In the adolescent population it is performed in patients who are skeletally mature with symptoms related to acetabular dysplasia. Redistribution of stresses through the hemipelvis after PAO can lead to a fracture at the ischio-pubic junction (IPJ).

METHODS

This is an IRB-approved, retrospective analysis of adolescent patients treated with a PAO for acetabular dysplasia from 1999 to 2012 at a single institution. Radiographic measurements were performed to include the lateral center-edge angle, Sharp acetabular index, and acetabular index of the weight-bearing zone. These were measured preoperatively and at 6-weeks and 1 year postoperatively from a standing anterior posterior pelvis radiograph. Postoperative modified Harris hip scores (mHHS) were also analyzed. Patients over the age of 21 at time of surgery and those with <2 years of follow-up were excluded.

RESULTS

One hundred sixty-six patients (187 operated hips) at an average age of 15.6±2.5 were included. Twelve (6.4%) fractures at the IPJ were identified in 12 patients. Seven were identified on the initial postoperative films, whereas 5 were identified after the 6-week visit. Seven (58.3%) fractures had an associated superior posterior ramus nonunion. Six (50%) healed by 2 years after surgery; the remaining 6 (50%) went on to nonunion. Compared with those without a fracture, there was no significant difference in preoperative, 6 weeks postoperative, and final center-edge angle (P=0.94, 0.29, 0.27), Sharp acetabular index (P=0.95, 0.38, 0.16), or AIBWZ (P=0.37, 0.21, 0.54). There was no difference in postoperative mean modified Harris hip scores (P=0.63). Analysis of predisposing factors demonstrated that patients with Charcot-Marie-Tooth (CMT) disease were more likely to develop an IPJ fracture (P=0.001). Patients with an IPJ fracture were older (17.1 vs. 15.5, P=0.05). There was no difference based on patient sex (P=0.22).

DISCUSSION AND CONCLUSIONS

The incidence of fracture at the IPJ after PAO in the adolescent population is 6.4% with some occurring at the time of surgery. These fractures are also associated with a nonunion at the superior posterior ramus cut and an underlying diagnosis of Charcot-Marie-Tooth. These fractures are not clinically significant and in this series did not merit further intervention when identified.

LEVEL OF EVIDENCE

Level III.