Does Periacetabular Osteotomy Affect the Load Distribution on the Knee?

Background: The effect of high tibial osteotomy (HTO) on the stress distribution across the knee joint is not completely understood. Subchondral bone density is considered to reflect the pattern of stress distribution across a joint surface. Purpose: To assess the distribution of subchondral bone density across the proximal tibia in nonarthritic knees and in the knees of patients with osteoarthritis (OA) before and after HTO. Study Design: Cohort study; Level of evidence, 3. Methods: We retrospectively collected radiological and computed tomography data from 16 patients without OA (control group) and 17 patients with OA. Data from the OA group were collected before and 1.5 years after HTO. Subchondral bone density of the proximal tibia was assessed with computed tomography–osteoabsorptiometry. The locations and percentages represented by high-density areas (HDAs) on the articular surface were quantitatively analyzed. Results: The ratio of the HDA of the medial compartment to the total HDA (medial ratio) was significantly higher in the preoperative OA group (mean, 80.1%) than in the control group (61.3%) (P < .001). After HTO, the medial ratio decreased significantly to 75.1% (P = .035 in comparison with preoperative values) and was significantly correlated with the hip-knee-ankle angle in both groups: control (r = −0.551; P = .033) and OA (r = −0.528; P = .043). The change in medial ratio after HTO was significantly correlated with the change in hip-knee-ankle angle (r = 0.587; P = .035). In the medial compartment, the HDA in the most lateral region of 4 subregions increased after HTO, but that in 3 medial subregions decreased. Conclusion: In this exploratory study, HTO shifted the HDA of the medial compartment of the proximal tibial articular surface toward the lateral compartment. In contrast, the HDA of the most lateral region of the medial compartment increased after HTO. This change in subchondral bone density may result from the change in stress distribution.

Meniscus extrusion and lower leg alignment predict the distribution of subchondral bone density across the knee joint.

ABSTRACTPatients with developmental dysplasia of the hip (DDH) who undergo periacetabular osteotomy (PAO) often have labral tears. The objective of this retrospective study was to compare PAO alone with PAO combined with arthrotomy or arthroscopy in DDH patients who had a full-thickness labral tear on magnetic resonance imaging. In total, 47 hips in the PAO group (PAO) were compared with 60 hips in the PAO with concomitant arthrotomy or arthroscopy (PAO-A) with respect to Hip Disability and Osteoarthritis Outcome Score (HOOS), modified Harris Hip Score (mHHS), Visual Analog Scale (VAS), clinical and radiographic outcomes at a median of 29 months. Reoperation rate and complications were compared between two groups of treatment. The PAO group was younger than the PAO-A group (25.2 ± 9.7 versus 31.3 ± 8.3). The PAO group was more likely to have worse dysplasia: lateral center edge angle (7.6°±9.63° versus 10.8°±6.85°) and anterior center edge angle (4°±12.92° versus 10.8°±9.92°). The PAO group had a higher preoperative mHHS (65.2 ± 15.3 versus 57.8 ± 14.8) and HOOS (66.3 ± 17.5 versus 55.8 ± 20.1). There were no significant differences in final functional outcome scores across treatment groups: mHHS (PAO; 86.8 ± 12.4 versus PAO-A, 83.3 ± 17.2), HOOS (86.5 ± 13.3 versus 82.5 ± 16.8) and VAS (2.5 ± 2.8 versus 2.5 ± 3.1). There was no difference in reoperation rate between two groups (6.4% versus 11.6%, P = 0.51). The overall complication rate was lower in the PAO group (26% versus 68%), but major complications were comparable. On the basis of our data, we were not able to conclusively demonstrate a clear benefit for the routine treatment of all labral tears; however, arthrotomy or arthroscopy may play a role in some conditions.

BackgroundSome patients with developmental dysplasia of the hip (DDH) complained of anterior knee pain (AKP) before and after Bernese periacetabular osteotomy (PAO) surgery. The purpose of this study was to (1) identify the characteristics of patellofemoral joint (PFJ) deformities in patients with DDH and (2) to determine the effects of PAO on the PFJ.MethodsSeventy patients (86 hips) were included in the DDH group. Thirty-three patients (33 knees) without AKP and hip pain were included in the control group. All patients underwent simultaneous CT scans of the hip and knee joints before PAO and after hardware removal surgery. The distance from the anterior inferior iliac spine to the ilioischial line (DAI), was measured in DDH patients. Imaging parameters of knees, including the sulcus angle (SA), femoral trochlear depth (FTD), patellar width (PW), tibial tuberosity-trochlear groove (TT-TG), patellar tilt angle (PTA) and lateral shift of the patella (LSP) were measured in patients in both the DDH and control group. TT-TG, PTA, and LSP of DDH patients were measured before PAO and after hardware removal. The DAI, PTA, LSP and TT-TG of all DDH patients before and after Bernese PAO were compared using paired t-tests. The FTD, PW, and SA of the DDH patients and the control group were analyzed using independent t-tests. PTA, TT-TG, and LSP between the control group and preoperative DDH patients, between the control group and post PAO patients were compared using independent t-tests.ResultsThe DAI changed from 4.04 ± 0.61 mm before PAO surgery to 5.44 ± 0.63 mm after PAO surgery. The SA of the DDH group (140.69 ± 11.30 degree) was greater than that of the control group (130.82 ± 6.43 degree). The FTD and the PW of the DDH group (5.45 ± 1.59 mm, 4.16 ± 0.36 mm) were smaller than that of the control group (7.39 ± 1.20 mm, 4.24 ± 0.38 mm). The changes in LSP, PTA, and TT-TG before and after surgery were not statistically significant. Both before and after PAO, there was no statistically significant difference in the parameters of LSP, PTA, and TT-TG compared with the control group.ConclusionThe knee joints of DDH patients presented a certain degree of femur trochlear groove dysplasia and patellofemoral instability. PAO surgery did not change PFJ stability, although the origination point of the rectus femoris muscle moved laterally during PAO surgery.

Some patients opt to undergo conversion to a THA for continued pain or progression of hip arthritis after periacetabular osteotomy. Whether patients are at greater risk for postoperative complications, revision THA, poor clinical outcomes, or compromised radiographic results after periacetabular osteotomy is debatable. When compared with a matched cohort of patients who underwent THAs for developmental dysplasia of the hip (DDH) without previous periacetabular osteotomy, we asked whether a THA after a periacetabular osteotomy has (1) a higher complication rate, (2) a higher likelihood of resulting in revision THA, (3) comparable improvements in Harris hip score, and (4) comparable radiographic results. A multicenter retrospective review of 562 patients undergoing 645 periacetabular osteotomies was performed. Twenty-three hips in 22 patients underwent a THA after periacetabular osteotomy. The patients were matched for age, sex, and BMI with 23 hips in 23 patients with DDH undergoing THA without a history of periacetabular osteotomy. Minimum followup for both groups of patients was 2 years (mean, 10±4 years and 6±4 years, respectively). Comparisons were made to answer the study questions based on a retrospective review from prospectively maintained registries of clinical and radiographic information at two participating centers. With the numbers available, there was no difference in complication or revision rates between the two groups (p=0.489 and 1.000, respectively); however, a post hoc power analysis showed our study was underpowered to detect a difference in the rate of postoperative complications or revision THA. There was marked improvement in Harris hip score with THA after periacetabular osteotomy (p<0.001) and THA for DDH (p<0.001), but there was no difference (p=0.265) in the Harris hip score at final followup between either group. The acetabular component was placed at a mean of 17° more retroversion during THA after periacetabular osteotomy compared with THA for DDH (p=0.002). This study did not detect any differences in the clinical outcomes in patients undergoing THA after periacetabular osteotomy done with a modern abductor-sparing approach when compared with a matched cohort undergoing THA for DDH. However, even with patients tallied across two high-volume centers during nearly 15 years, our study was underpowered to detect potentially important differences between the THA after periacetabular osteotomy group and the THA for DDH group. The data in this report are suitable as pilot data for future studies and for systematic reviews. Larger multicenter studies are needed to understand how the technical challenges of THA after periacetabular osteotomy affect postoperative complications and revision THA. Level III, therapeutic study.

Pain and quality of life are impaired in adults with hip dysplasia undergoing periacetabular osteotomy: a systematic review and meta-analysis

The significance of the relationship between the spine and hip joints has been frequently discussed. However, the relationship between acetabular coverage and spinal sagittal alignment has not been fully elucidated as previous studies did not adequately control for factors that might affect the spinopelvic alignment. The aim of this study was to elucidate the impact of acetabular coverage on spinal sagittal alignment by comparing patient groups matched on sex, age, and the presence of hip and anterior impingement pain. We prospectively enrolled 30 women undergoing periacetabular osteotomy (PAO) for developmental dysplasia of the hip (DDH) and 30 women undergoing hip arthroscopic surgery (HAS) for labral tears. The lateral centre edge angle was measured on hip radiographs. In addition, the sagittal vertical axis, pelvic tilt, pelvic incidence, sacral slope (SS), and lumbar lordosis (LL) were measured on preoperative plain radiographs of the whole spine to assess the sagittal spinal alignment. Clinical and radiologic data were compared between the two groups (PAO vs. HAS). The patient groups did not differ in age and body mass index. The mean SS was significantly greater in the PAO group (41.6° ± 1.6°) than in the HAS group (35.3° ± 1.5°; P = 0.0039). Additionally, the mean LL was significantly greater in the PAO group (54.5° ± 2.0°) than in the HAS group (45.1° ± 1.9°; P = 0.0015). The SS and LL were greater in patients with DDH than in patients with hip pain, but without DDH. Patients with DDH might show lumbar hyperlordosis to rotate the pelvis anteriorly, increasing the anterosuperior acetabular coverage.

Glenoid subchondral bone density distribution in male total shoulder arthroplasty subjects with eccentric and concentric wear

The hoop function of the meniscus plays a crucial role in stress distribution across the knee joint. While medial meniscal extrusion is known to contribute to the progression of medial knee osteoarthritis (OA) by altering load distribution within the knee joint, its exact effect on living humans remains unclear. To investigate the influence of meniscal extrusion on subchondral bone density distribution in patients with medial knee OA. Cross-sectional study; Level of evidence, 3. This retrospective study included 59 patients with medial knee OA (OA group) and 19 control participants (non-OA group). Radiographic parameters, including the hip-knee-ankle angle (HKA) and meniscal extrusion ratio (MER), were assessed. The subchondral bone density was evaluated using computed tomography-osteoabsorptiometry to analyze the high-density area (HDA) in the medial and lateral compartments on the articular surface of the proximal tibia. Correlations between these parameters were assessed using single and multiple regression analyses, with subgroup analysis conducted in OA patients with and without meniscal tears. In the OA group, the HKA, medial MER (MMER), and the ratio of the medial compartment HDA to the total HDA (medial ratio) were -7.4°, 64.8%, and 81.8%, respectively. In the non-OA group, these values were -2.1°, 12.5%, and 62.0%. Simple regression analysis showed that, in the OA group, the medial ratio was correlated with HKA (R 2 = 0.216; P < .001) and MMER (R 2 = 0.307; P < .001). Among non-OA participants, only MMER was correlated with the medial ratio (R 2 = 0.217; P = .045). The multivariable regression analysis demonstrated an adjusted R 2 value of 0.38 (P < .001) in the OA group. The standardized coefficients were 0.465 for MMER and -0.340 for HKA. Subgroup analysis further indicated that meniscal injury in OA patients amplified the effect of extrusion on subchondral bone density distribution, with an adjusted R 2 of 0.54 in the meniscal tear group. MMER had a greater influence on the mediolateral distribution of subchondral bone density in patients with medial knee OA than lower limb alignment, suggesting that the hoop function of the meniscus plays a more important role in altering stress distribution than leg alignment.

Background: Repetitive valgus stress applied during a throwing motion can lead to various elbow disturbances, including ulnar collateral ligament (UCL) injury. Subchondral bone density reportedly reflects the cumulative force on a joint surface under actual loading conditions. Purpose: (1) To evaluate the distribution of subchondral bone density across the elbow joint in asymptomatic baseball pitchers and symptomatic valgus instability pitchers and (2) to clarify the alterations in stress distribution pattern associated with symptomatic UCL insufficiency pitching activities. Study Design: Controlled laboratory study. Methods: Computed tomography (CT) imaging data were collected from the dominant-side elbow of 7 nonathletic volunteers (controls), 12 asymptomatic pitchers (asymptomatic group), and 12 symptomatic valgus instability pitchers with UCL insufficiency (symptomatic group). Bone mineral density across the elbow joint was measured with CT osteoabsorptiometry. A 2-dimensional mapping model was divided into 4 areas of the distal end of the humerus and 5 areas of the ulna with the radial head. The locations and percentages of high-density areas on the articular surface were quantitatively analyzed. Results: High-density areas in the asymptomatic and symptomatic groups were found in the anterolateral and posteromedial parts of the humerus and in the radial head, posteromedial to the ulna. The high-density areas in the anterior and posteromedial of the humerus, the radial head, and the posteromedial part of the ulna in the controls were smaller than those in the baseball group. In the symptomatic group, the percentages of high-density areas in the anterolateral part of the humerus (mean, 36.3%; 95% CI, 31.9%-40.7%) and the anterolateral part of the ulna (mean, 31.7%; 95% CI, 24.3%-39.1) were significantly greater than those in the asymptomatic group (P = .047 and P < .0001, respectively). Conclusion: Symptomatic UCL insufficiency was associated with characteristic high-stress distribution patterns on the anterolateral part of the capitellum and the anterolateral part of the ulna. The current results indicate that symptomatic UCL insufficiency produces excessive and cumulative stress in the elbow joint. Clinical Relevance: The information obtained from the CT images can useful for early detection of overstress conditions of the elbow joint.

Purpose: To evaluate the results of a periacetabular osteotomy (PAO) combined with a femoral osteotomy (FO) for a dysplastic hip with a deformed femoral head. Materials and Methods: Thirteen hips with dysplasia and a deformed femoral head were followed up for more than 12 months. Eight hips were in the PAO group and 5 hips were in the PAO and FO group. The two groups were compared clinically according to the HHS (Harris hip score), pain and limping VAS (visual analogue scale), and radiologically according to the CEA (central edge angle of Wiberg), Tonnis angle (acetabular index of weight bearing surface), FHC (femoral head coverage), AA (acetabular angle of Sharp), DBSPFH (distance between symphysis pubis and femoral head) and AI (acetabular index of depth to width). Results: Regarding the clinical results, the PAO group showed improvement in the HHS from 66.5 preoperatively to 90.4 postoperatively (p=0.01) and the pain VAS from 6.7 to 1.9 (p=0.01). However, there was no significant improvement in limping (p=0.39). In the PAO with FO group, the HHS was improved from 78 to 91 (p=0.04). Radiologically, the CEA, Tonnis angle, FHC, AA and AI improved significantly but there were no significant improvement in the DBSPFH in the two groups. In addition, there was no significant clinical or radiological difference between the two groups. Conclusion: Periacetabular osteotomy is recommended for dysplastic hips with deformed femoral head. A concomitant femoral osteotomy should be considered in hips with a severely deformed femoral head.

Computed Tomography Osteoabsorptiometry Alterations in Stress Distribution Patterns Through the Wrist After Radial Shortening Osteotomy for Kienböck Disease

Ostéotomie périacétabulaire versus prothèse totale de hanche pour arthrose sur dysplasie chez les sujets jeunes et actifs : analyse systématique et méta-analyse

Periacetabular osteotomy vs. total hip arthroplasty in young active patients with dysplastic hip: Systematic review and meta-analysis

Despite the availability of long-term follow-up data, the effect of pelvic osteotomy on the natural history of osteoarthritis is not yet fully understood, partly because there is untapped potential for radiographs to better describe osteoarthritis. Therefore, this study aimed to assess the distribution of subchondral bone mineral density (BMD) across the acetabulum in patients with hip dysplasia immediately (2 weeks) and 1 year after undergoing periacetabular osteotomy (PAO). To that end, we reviewed 40 hips from 33 patients with developmental dysplasia of the hip who underwent PAO between January 2016 and July 2019 at our institution. We measured subchondral BMD through the articular surface of the acetabulum using computed tomography osteoabsorptiometry, dividing the distribution map into nine segments. We then compared the subchondral BMD between 2 weeks and 1 year after PAO in each area. At 2 weeks after PAO, the high-density area tended to be localized particularly in the lateral part of the acetabulum, whereas 1 year after PAO, the high-density area moved to the central and lateral parts. The percentage ratios of the subchondral BMD for the central-posterior, lateral-central, and lateral-posterior areas relative to the central-central area were significantly decreased at 1 year after PAO, as compared to those at 2 weeks after PAO. These findings suggest that loading was altered by PAO to be more similar to physiological loading. A long follow-up observational study is warranted to confirm the association between early changes in subchondral BMD by PAO and joint degeneration.