Objective To compare the biomechanical effects between rotational acetabular osteotomy and Chiari osteotomy for developmental dysplasia of the hip (DDH) by biomechanical test. Methods Sixteen DDH models of 8 human cadaver specimens were prepared by resecting the upper edge and posterior edge of acetabulum. And the Wiberg central-edge angle (CE) of the DDH model was less than 20°. Then the rotational acetabular osteotomy was performed on the left hip and Chiari osteotomy on the right hip. When 600 N loading was loaded at 5 mm/minute by a material testing machine, the strain values of normal specimens, DDH specimens, and 2 models after osteotomies were measured. Results In normal specimens, the strain values of the left and right hips were 845.63 ± 533.91 and 955.94 ± 837.42 respectively, while the strain values were 1 439.03 ± 625.23 and 1 558.75 ± 1 009.46 respectively in DDH specimens, which was about 2 times that of normal hips. The morphology and X-ray examinations indicated that the DDH model was successfully established. The strain value was 574.94 ± 430.88 after rotational acetabular osteotomy, and was significantly lower than that of DDH specimens (t=4.176, P=0.004); the strain value was 1 614.81 ± 932.67 after Chiari osteotomy, showing no significant difference when compared with that of DDH specimens (t=0.208, P=0.841). The strain value relieved by rotational acetabular osteotomy was significantly higher than that by Chiari osteotomy (t= — 2.548, P=0.023). Conclusion Rotational acetabular osteotomy is better than Chiari osteotomy in relieving hip joint stress of DDH.
ObjectiveTo analyze and summarize the short-term effectiveness of total hip arthroplasty (THA) with a tapered, modular neck hip stem for developmental dysplasia of the hip (DDH). MethodsBetween October 2010 and May 2012, 28 patients (31 hips) with DDH and secondary osteoarthritis underwent THA with a tapered, modular neck hip stem. There were 2 males and 26 females, with an average age of 61 years (range, 47-77 years). The unilateral hip was involved in 25 cases and bilateral hips in 3 cases. According to the Crowe system, 22 cases were classified as Crowe type I, 8 as Crowe type Ⅱ, and 1 as Crowe type Ⅲ. At preoperation, the leg length discrepancy was (1.6±0.8) cm; the hip range of motion values were (76.1±12.8)° in flexion, (14.5±6.7)° in abduction, (9.0±4.5)° in adduction, (13.1±6.4)° in internal rotation, and (11.7±7.0)° in external rotation; and the Harris hip score was 44.7±11.1. ResultsFemoral neck fracture occurred in 2 cases (2 hips) during operation, which healed by fixed with steel wire. The incisions healed by first intention. No related complication occurred. The mean follow-up time was 20 months (range, 12-32 months). At last follow-up, the leg length discrepancy was significant decreased to (1.0±0.5) cm (t=-3.512, P=0.002). The hip range of motion values were (102.9±10.1)° in flexion, (32.9±6.0)° in abduction, (19.2±4.3)° in adduction, (34.4±4.2)° in internal rotation, and (32.3±5.1)° in external rotation, all showing significant differences when compared with preoperative values (P<0.05). The Harris hip score was significantly improved to 90.3±6.1 (t=21.263, P=0.000). The X-ray films showed no subsidence, loosening, or breakage in the other cases except 2 cases having subsidence (<2 mm) within 1 year. Heterotopic ossification occurred in 2 hips. ConclusionThe short-term effectiveness of THA with a tapered, modular neck hip stem for DDH is satisfactory. However, the medium and long-term effectiveness still need further follow-up.
Objective To investigate the morphological changes of the proximalfemur and their implication to the total hip arthroplasty in patients with Crowe Ⅱ/Ⅲ developmental dysplasia of the hip (DDH). Methods The experimental gr oup was composed of 15 hips in 14 patients (Crowe Ⅱ, 9 hips; Crowe Ⅲ, 6 hips ) with osteoarthritis secondary to Crowe Ⅱ/Ⅲ DDH (2 males, 12 females; age, 35-61 years). None of the patients had accepted any osteotomy treatment. The control group was composed of 15 normal hips in 15 patients with unilateral DDH (3 males, 12 females; age, 35-57 years). Twelve hips came from the experimental group and the other 3 came from the patients with unilateral Crowe Ⅰ DDH. The femurswere examined with the CT scanning. The following parameters were measured: theheight of the center of the femoral head (HCFH), the isthmus position (IP), theneckshaft angle(NS), the anteversion angle, the canal flare index, and the canal width. Then, the analysis of the data was conducted. Results HCFH and IP in theexperimental group and the control group were 50.1±6.7 mm, 50.1±7.4 mm, and 107.4±21.5 mm, 108.7±18.1 mm，respectively, which had no significant differencebetween the two groups（Pgt;0.05）. In the experimental group and the control group, the NS were 138.3±10.0° and 126.7±5.7°，the anteversion angles were 36.5±15.9° and 18.8±5.4°, and the canal flare indexes were 4.47±0.40and 5.01±0.43. There was a significant difference between the two groups in the above 3 parameters （Plt;0.05）. As for the canal width of the femur, therewasa significant difference in the interior/exterior widths and the anterior/posterior widths at the level of 2 cm above the lesser trochanter and 4 cm belowthe lesser trochanter between the two groups （Plt;0.05）; however, there was nosignificant difference in the canal width of the femur at the isthmus between the two groups（P＞0.05）. Conclusion It is necessary to evaluate the morphology of the proximal femur before the total hip arthroplasty performed in patients with Crowe Ⅱ/Ⅲ DDH. The straight and smaller femoral prosthesis should be chosen and implanted in the proper anteversion position duringoperation.
Objective To evaluate early to medium-term effectiveness of total hip arthroplasty (THA) in patients with a history of hip preservation surgery with secondary severe osteoarthritis for developmental dysplasia of the hip (DDH). Methods The clinical data of 25 DDH patients (31 hips) who had severe osteoarthritis after hip preservation surgery and received THA between September 2009 and March 2021 were retrospectively analyzed. There were 1 male and 24 females; the age ranged from 18 to 65 years, with an average age of 43 years; 8 hips were classified into Crowe type Ⅰ, 9 hips were type Ⅱ, 3 hips were type Ⅲ, and 11 hips were type Ⅳ. The time between osteotomy and THA ranged from 31 to 51 years, with an average of 31.96 years. Preoperative hip flexion range of motion was (69.31±29.72)°, abduction range of motion was (24.00±14.79)°; and Harris hip score was 45.3±15.5. Postoperative Harris hip score, hip range of motion, complications, radiographic findings, and implant survival rate were analyzed. Results Patients in both groups were followed up 2-132 months, with an average of 51 months. During the follow-up, periprosthetic fracture occurred in 1 case; there was no complication such as dislocation, periprosthetic infection, nerve palsy, or deep vein thrombosis. At last follow-up, the hip flexion range of motion was (109.52±11.17)°, abduction range of motion was (41.25±5.59)°, showing significant differences when compared with preoperative values (t=8.260, P=0.000; t=6.524, P=0.000). The Harris hip score was 91.5±4.1, and the difference was significant when compared with preoperative score (t=11.696, P=0.000); among them, 13 cases were excellent and 12 cases were good. Radiographic evaluation showed that the center of acetabular rotation moved up 0-18 mm (mean, 6.35 mm). The cup abductor angle was 28°-49° (mean, 37.74°) and the coverage rate was 69.44%-98.33% (mean, 81.04%). All femoral stems were fixed in neutral position without varus or valgus. No osteolysis, radiolucent line, or implant migration was observed. By the end of follow-up, none of the patients underwent revision and the survival rate of prothesis was 100%. ConclusionTHA is still the gold standard for the treatment of DDH patients with secondary osteoarthritis after hip preservation surgery. The postoperative joint function can be rapidly restored, the patients’ quality of life can significantly improve, and the early to medium-term survival rate of the prosthesis is satisfactory.
Objective To investigate the effectiveness of subtrochanteric shortening with overlapping femoral resection in total hip arthroplasty for Crowe type IV developmental dysplasia of the hip (DDH). Methods Between January 2004 and December 2010, 37 patients (44 hips) with Crowe type IV DDH underwent subtrochanteric shortening with overlapping femoral resection in total hip arthroplasty with cementless prosthesis. There were 15 males (18 hips) and 22 females (26 hips) with an average age of 42 years (range, 24-46 years). Unilateral hip was involved in 30 cases and bilateral hips in 7 cases. Preoperative X-ray films showed complete dislocation of the femoral head and hypoplasia of the acetabulum and proximal femur. Before operation, the leg discrepancy was (5.5 ± 1.1) cm, and the Harris score was 32.1 ± 5.2. Results The mean operation time was 4.3 hours (range, 3-6 hours); the mean blood loss was 760 mL (range, 600-1 000 mL). All patients obtained primary healing of incision. The patients were followed up 1-8 years (mean, 6.7 years). Pain relief was achieved; 6 cases had mild claudication; 3 cases had femoral nerve palsy; and no stretch injury of sciatic nerve was observed. X-ray films showed that acetabular cups were in normal position. The healing time of fracture was 3-6 months (mean, 3.7 months). The leg discrepancy was (1.5 ± 1.0) cm at 1 day after operation, showing significant difference when compared with preoperative one (t=16.45, P=0.00). The Harris score was 94.3 ± 3.8 at 3 months after operation, showing significant difference when compared with preoperative score (t=59.15, P=0.00). No revision of acetabular and femoral prostheses was performed during follow-up. Conclusion Subtrochanteric shortening with overlapping femoral resection in total hip arthroplasty is a safe method of restoring the anatomic hip center in Crowe type IV DDH in adults. It can avoid reduction difficulty caused by soft tissue contracture and injuries of sciatic nerve and femoral nerve caused by limb lengthening.
Objective To summarize the biomechanical characteristics, diagnosis, and hip arthroscopic treatment of borderline developmental dysplasia of hip (BDDH) with Cam-type femoroacetabular impingement (Cam FAI). Methods The literature on BDDH with Cam FAI at home and abroad in recent years was extensively reviewed and analyzed. Results In patients with BDDH and Cam FAI, the femoral neck anteversion angle and femoral neck shaft angle increase, the pelvis tilts, and the acetabulum rotates, resulting in instability of the hip joint. In order to maintain the stability of the hip joint, the direction of biomechanical action of the hip joint has changed, which further affects the anatomical structures such as the proximal femur and acetabular morphology. BDDH with Cam FAI can be diagnosed clinically by combining lateral center edge angle, anterior center edge angle, and acetabular index. BDDH with Cam FAI can be effectively treated through arthroscopic polishing of the edges of the acetabular proliferative bone, excision of Cam malformations, and minimally invasive repair of the glenoid lip and cartilage of the hip joint. Conclusion Currently, there is no unified standard for the diagnosis and treatment of BDDH with Cam FAI. Minimally invasive treatment of the hip under arthroscopy can achieve good early- and medium-term effectiveness, and has certain advantages in repairing and maintaining the integrity of the glenoid lip and suturing/compression joint capsule. However, the long-term effectiveness needs to be further followed up to determine. The timing of surgery, intraoperative bone edge depth polishing, and joint capsule suturing/compression techniques also need to be further explored.
ObjectiveTo measure and analyze the radiographic characteristics of the leg length discrepancy in adult patients with unilateral developmental dysplasia of the hip (DDH).MethodsThe clinical data of 112 patients with unilateral DDH who met the selection criteria between January 2016 and June 2018 were retrospectively analyzed. There were 16 males and 96 females with an age of 20-76 years (mean, 42.9 years). According to the Crowe classification, there were 25 hips of type Ⅰ, 26 hips of type Ⅱ, 15 hips of type Ⅲ, and 46 hips of type Ⅳ (26 hips of type ⅣA without secondary acetabular formation, and 20 hips of type ⅣB with secondary acetabular formation). Full-length X-ray films of the lower limbs in the standing position were used to measure the following parameters: greater trochanter leg length (GTLL), greater trochanter femoral length (GTFL), lesser trochanter leg length (LTLL), lesser trochanter femoral length (LTFL), tibial length (TL), and intertrochanteric distance (ITD). The above parameters on the healthy and affected sides were compared and the difference of each parameter between the healthy and affected sides was calculated. Taking the difference of 5 mm between the healthy side and the affected side as the threshold value, the number of cases with the healthy side was greater than 5 mm and the affected side was greater than 5 mm were counted respectively. The difference of the imaging parameters between the healthy side and the affected side were compared between different Crowe types and between type ⅣA and type ⅣB.ResultsThere was no significant difference in GTLL and LTFL between healthy and affected sides (P>0.05); LTLL and TL of affected side were longer than healthy side, GTFL and ITD were shorter than healthy side, and the differences were significant (P<0.05). The constituent ratio of long cases on the affected side of TL and LTLL was greater than the constituent ratio of long cases on the healthy side, while the constituent ratio of long cases on the healthy side of GTFL and ITD was greater than the constituent ratio of long cases on the affected side; there was no obvious difference in the constituent ratio of long cases on the healthy side or the affected side of GTLL and LTFL. The comparison between different Crowe types showed that only the difference in TL between type Ⅰ and type Ⅳ was significant (P<0.05), the difference of each imaging parameter among the other types showing no significant difference (P>0.05). Compared with type ⅣB, the differences of GTLL, TL, and ITD of type ⅣA were bigger, and the differences were significant (P<0.05); the differences of other parameters between type ⅣA and type ⅣB were not significant (P>0.05).ConclusionIn adult unilateral DDH patients, the leg length on the healthy side and the affected side is different, and the difference mainly comes from the TL and ITD, which should be paid attention to in preoperative planning.
Objective To investigate the effects of femoral offset and mechanical axis of the lower extremity on hip after osteotomy for adult developmental dysplasia of the hip (DDH). Methods A clinical data of 62 adult patients with DDH (62 hips), who underwent periacetabular osteotomy combined with femoral osteotomy between January 2016 and May 2019 and met selective criteria, was retrospectively analyzed. There were 6 males and 56 females. The age ranged from 18 to 38 years, with an average of 24.4 years. Body mass index ranged from 15.8 to 31.8 kg/m2, with an average of 21.8 kg/m2. There were 44 cases of Hartofilakidis typeⅠ and 18 cases of typeⅡ. According to the modified Tönnis osteoarthritis staging, 46 cases were stage 0 and 16 cases were stageⅠ. There were 13 cases with pelvic anteversion, 40 cases with normal pelvis, and 9 cases with pelvic retroversion. Intraoperative blood loss, length of hospital stay, and complications were recorded. Postoperative hip function was evaluated by Harris score and International Hip Outcome Tool (iHOT) score. The femoral offset, collo-diaphyseal angle, hip-knee-ankle angle (HKA), knee valus angle, CE (Wiberg central-edge angle), anterior CE angle, and acetabular index angle were measured and the osteotomy healing was observed on X-ray films. Patients were grouped according to postoperative femoral offset (≥48 mm or <48 mm) and HKA [varus group (HKA<177°), normal group (HKA 177°-183°), and valgus group (HKA>183°)]. Harris score and iHOT score were compared between groups. Results Intraoperative blood loss ranged from 200 to 1 550 mL, with an average of 476 mL. The length of hospital stay ranged from 8 to 21 days, with an average of 13.3 days. All incisions healed by first intention. All patients were followed up 2.0-4.5 years, with an average of 2.8 years. At 1 year after operation, the Harris score and iHOT score of the hip joint significantly increased when compared with those before operation (P<0.05); there were significant differences in the femoral offset, collo-diaphyseal angle, HKA, knee valus angle, CE angle, anterior CE angle, and acetabular index angle between pre- and post-operation (P>0.05). According to the modified Tönnis osteoarthritis staging, 38 cases were stage 0 and 24 cases were stageⅠ; and there was no significant difference between pre- and post-operation (χ2=2.362, P=0.124). There were 11 cases with pelvic anteversion, 38 cases with normal pelvis, and 13 cases with pelvic retroversion, showing no significant difference when compared with that before operation (χ2=0.954, P=0.623). The pubic branch osteotomy did not heal in 9 cases, proximal femur osteotomy did not heal in 2 cases, and inferior pubic ramus stress fracture occurred in 5 cases. There were significant differences (P<0.05) in the Harris score and iHOT score between femoral offset≥48 mm group (n=10) and femoral offset<48 mm group (n=52). There was no significant difference (P>0.05) in Harris score and iHOT score between varus group (n=13), normal group (n=40), and valgus group (n=9). Conclusion Periacetabular osteotomy combined with femoral osteotomy can improve the femoral offset and mechanical axis of the lower extremity of patients with DDH, and improve the functional score of the hip. However, excessive increase of femoral offset during femoral osteotomy is not desirable, resulting in low postoperative functional score.
Objective To summarize the characteristics and biomechanical research progress of common acetabular reconstruction techniques in patients with Crowe type Ⅱ and Ⅲ developmental dysplasia of the hip (DDH) undergoing total hip arthroplasty (THA), and provide references for selecting appropriate acetabular reconstruction techniques for clinical treatment of Crowe type Ⅱ and Ⅲ DDH. Methods The domestic and foreign relevant literature on biomechanics of acetabular reconstruction with Crowe type Ⅱ and Ⅲ DDH was reviewed, and the research progress was summarized.Results At present, there are many acetabular reconstruction techniques in Crowe type Ⅱ and Ⅲ DDH patients undergoing THA, with their own characteristics due to structural and biomechanical differences. The acetabular roof reconstruction technique enables the acetabular cup prosthesis to obtain satisfactory initial stability, increases the acetabular bone reserve, and provides a bone mass basis for the possible secondary revision. The medial protrusio technique (MPT) reduces the stress in the weight-bearing area of the hip joint and the wear of the prosthesis, and increases the service life of the prosthesis. Small acetabulum cup technique enables shallow small acetabulum to match suitable acetabulum cup to obtain ideal cup coverage, but small acetabulum cup also increases the stress per unit area of acetabulum cup, which is not conducive to the long-term effectiveness. The rotation center up-shifting technique increases the initial stability of the cup. Conclusion Currently, there is no detailed standard guidance for the selection of acetabular reconstruction in THA with Crowe type Ⅱ and Ⅲ DDH, and the appropriate acetabular reconstruction technique should be selected according to the different types of DDH.