The Development of Leg Length Difference and Influence on Persistent Dysplasia in Patients with Developmental Dysplasia of the Hip

Integrated Acetabular Prosthesis Versus Bone Grafting in Total Hip Arthroplasty for Crowe Type II and III Hip Dysplasia: A Retrospective Case-Control Study

OBJECTIVE

Many methods of acetabular reconstruction with total hip arthroplasty (THA) for Crowe type II and III adult developmental dysplasia of the hip (DDH) acetabular bone defect have been implemented clinically. However, there was no study comparing the results of integrated acetabular prosthesis (IAP) with bone grafting (BG). This study aims to investigate the efficacy of IAP and BG for acetabular reconstruction in Crowe type II and III DDH.

METHODS

The clinical data of 45 patients with unilateral Crowe type II and III DDH who underwent THA from January 2020 to January 2023 were retrospectively analyzed. The patients were divided into two groups: 25 patients using 3D-printed IAP (IAP group) and 20 patients using BG (BG group). The operation time and intraoperative blood loss were recorded. The clinical outcomes were assessed by Harris Hip Score (HHS) and full weight-bearing time. The radiological outcomes were evaluated by the radiological examination. Accordingly, intraoperative and postoperative complications were observed as well. The data between the two groups were compared by independent sample t-tests and the Mann-Whitney U rank sum test.

RESULTS

There were no significant differences between the two groups in Harris Hip Score (HHS) (preoperative, 6 months postoperative, and the last follow-up), leg length discrepancy (LLD), cup inclination, cup anteversion, vertical center of rotation (V-COR), horizontal center of rotation (H-COR) (p > 0.05). The mean HHS in the IAP group was higher than in the BG group at 1 and 3 months postoperative (p < 0.001). The mean surgical time and blood loss in the IAP group were less than in the BG group (p < 0.001). The mean full weight-bearing time in the IAP group was shorter than in the BG group (p < 0.01). No complications were observed in either group during the follow-up period.

CONCLUSION

IAP and BG have similar radiographic outcomes and long-term clinical efficacy in THA for Crowe type II and III DDH, but the IAP technique has higher surgical safety and facilitates the recovery of hip joint function, which is worthy of clinical promotion.

Outcomes following medial open reduction in infants aged ≤6 months with developmental dysplasia of the hip

Aim

To evaluate mid-long term radiological outcomes following early medial approach open reduction (MAOR) performed for developmental dysplasia of the hip (DDH) in infants aged ≤6 months old at time of surgery, specifically incidence of clinically significant avascular necrosis (AVN), Severin outcomes and rates of further surgery.

Methods

This is a single centre retrospective study of patients treated from 1999 to 2017. Only infants aged ≤6 months old at time of MAOR, and aged at least 6 years old at latest follow-up were included (minimum 5.5 years follow-up). Data was collected from electronic healthcare records and serial radiographs reviewed to assess outcomes. AVN was classified according to Kalamchi and MacEwen, with types 2-4 considered clinically significant. Severin classes I (excellent) and II (good) were considered satisfactory outcomes, and classes III + considered unsatisfactory.

Results

MAOR was performed on 48 hips in 44 patients. Mean age at time of surgery was 4 months (SD 1.4, range 2-6), with mean follow-up of 9.8 years (SD 2.7, range 6.2-16.2). Clinically significant AVN developed in 9/48 hips (19 %), all of which were type 2. Only 1/48 hips (2 %) required a subsequent pelvic osteotomy due to residual dysplasia with subluxation at 2 years post MAOR. At final follow-up, 81 % of patients had excellent or good radiological outcomes (Severin I/II). No statistically significant predictors for developing AVN, including age and presence of ossific nucleus, were identified.

Conclusion

Early MAOR in infants aged ≤6 months was associated with a very low rate of significant residual dysplasia requiring further surgery, yet was not associated with unacceptable rates or severe forms of AVN. We therefore recommend MAOR is performed early to optimise acetabular remodelling potential and minimise the need for concurrent or subsequent bony procedures.

Relationship between perceived and structural leg length discrepancies of patients with hip osteoarthritis dysplasia

BACKGROUND

Only few studies have been conducted on leg length discrepancy (LLD) in patients with hip osteoarthritis (OA). This study aimed to examine the relationship between perceived LLD (pLLD) and structural LLD (sLLD) in patients with advanced OA and to determine the factors influencing both LLDs. This retrospective study aimed to answer the following questions: (1) are older adults less likely to perceive LLD than younger adults? (2) is there a relationship between pLLD and sLLD? and (3) is pLLD associated with patient satisfaction?

HYPOTHESIS

We hypothesized that older adults are less likely to perceive LLD than younger adults.

PATIENTS AND METHODS

We recruited 125 patients (102 women and 23 men) with hip OA associated with developmental dysplasia of the hip defined as grade 3 or higher according to the Tönnis classification and excluding contralateral grade 2 or higher. The mean age of the patients was 65.2±11.2 (36-85) years. Before surgery, 2-mm and 5-mm thick plates were placed on the floor on the plantar surface of the short leg to measure pLLD. Preoperative computed tomography (CT) was performed and sLLDs were measured using the 3D planning software ZedHip. The following associated factors were evaluated: age, height, weight, body mass index (BMI), adduction and abduction range of motion (ROM) of the affected hip joint, Crowe classification, standing pelvic inclination in the coronal plane, Cobb angle and Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ).

RESULTS

The absolute difference between pLLD and sLLD was modestly positively correlated with age (R=0.206; p<0.05) indicating older patients were less prone to perceive LLD. A strong positive correlation was found between pLLD (4.8±7.3mm; range: -37 to 28mm) and sLLD (6.4±7.0mm; range: -29.9 to 23.7mm) (R=0.714, p<0.05). The greater the pLLD, the smaller the hip abduction ROM (24.8±11.6°; range: 0 to 45°) tended to be, while the greater the sLLD, the smaller the hip abduction and adduction ROM (10.3±5.7°; range: 0 to 25°) tended to be (R= -0.259 and R= -0.297, respectively; p<0.05) The clinical significance of this finding is that pLLD may be improved if hip ROM training is performed before surgery. pLLD was significantly smaller in the group without pelvic inclination (8.0±14.1mm; range: -37 to 22mm) than in the group with pelvic inclination to the affected side (6.9±7.5mm; range: -12 to 28mm) and in the group with no inclination to the affected side (7.3±7.6mm; range: -8 to 25mm) (p<0.05) The clinical significance of this finding is that improving pelvic inclination with hip ROM training or muscle stretching may also reduce pLLD. No significant differences were noted between pLLD and JHEQ total scores or subgroups.

DISCUSSION

Older patients had less pLLD. Preoperative pLLD was strongly correlated with sLLD but not with patient satisfaction. These results may be useful for conservative treatment of OA, preoperative planning and intraoperative leg length correction.

LEVEL OF EVIDENCE

IV; case control study.

The Importance of Monitoring and Factors That May Influence Leg Length Difference in Developmental Dysplasia of the Hip

In unilateral Developmental Dysplasia of the Hip (DDH), avascular necrosis (AVN), femoral or pelvic osteotomy, and residual dysplasia causing subluxation of the proximal femur may influence Leg Length Discrepancy (LLD). This can lead to gait compensation, pelvic obliquity, and spinal curvature. The aim of this study is to determine the prevalence of LLD, establish which limb segment contributes to the discrepancy, describe how AVN influences LLD, and ascertain variables that may influence the need for LLD corrective procedures.

METHODOLOGY

This study assessed long-leg radiographs at skeletal maturity. Radiographs were assessed for the articulo-trochanteric distance (ATD) and femoral and tibial length. AVN was classified according to Kalamchi-MacEwen.

RESULTS

109 patients were included. The affected/DDH leg was longer in 72/109 (66%) patients. The length difference was mainly in the subtrochanteric segment of the femur. AVN negatively influenced leg length. Older (≥three years) patients with multiple procedures were more likely to have AVN. LLD interventions were performed in 30 (27.5%) patients. AVN grade or type of DDH surgery did not influence the odds of needing a procedure to correct LLD.

CONCLUSIONS

Procedures to correct LLD were performed irrespective of previous DDH surgery or AVN grades. In most patients, the affected/DDH leg was longer, mainly in the subtrochanteric segment of the femur, largely influenced by femoral osteotomy in patients with multiple operative procedures for DDH. We recommend careful monitoring of LLD in DDH.