Objective To evaluate the effect of preoperative digital planning in acetabular reconstruction of total hip arthroplasty (THA) for development dysplasia of the hip (DDH). Methods A prospective study was performed on 42 patients with DDH undergoing primary THA between January 2009 and December 2011. The patients were divided into 2 groups according to whether preoperative digital planning was made or not; before operation, conventional imaging method was used in 23 cases (group A), and TraumaCad software was used for preoperative digital planning in 19 cases (group B). There was no significant difference in gender, age, body mass index, DDH classification, and preoperative Harris score between 2 groups (P gt; 0.05). The operation time, amount of bleeding, and postoperative complication were observed. After 7 days of operation, X-ray films were done to measure the vertical location, horizontal location, radiographic anteversion angle, radiographic inclination angle, and prosthesis size by TraumaCad software. The qualified rate of cup placement was compared between 2 groups. Coincidence rate of cup size between preoperative predicted by the digital planning and actually implanted in group B also was calculated. Results The operation time and the amount of bleeding were (119.25 ± 47.16) minutes and (410.00 ± 200.39) mL in group A and were (155.31 ± 84.03) minutes and (387.50 ± 251.99) mL in group B respectively, showing no significant difference between 2 groups (P gt; 0.05). Incision infection and prosthetic anterior dislocation occurred in 1 case of group A respectively, prosthetic posterior dislocation in 1 case of group B. The patients were followed up 1 year and 1 month to 4 years and 1 month (mean, 2 years and 8 months ) in group A, and 1 year and 3 months to 4 years (mean, 2 years and 7 months) in group B. At last follow-up, the Harris scores were 91.09 ± 5.35 in group A and 91.72 ± 3.48 in group B, which were significantly increased when compared with preoperative scores (P lt; 0.05), but no significant difference was found between 2 groups (t=0.41, P=0.69). The qualified rate of cup placement of group B (78.95%, 15/19) was significantly higher than that of group A (43.48%, 10/23) (χ2=5.43, P=0.02); the coincidence rate of the cup size between preoperative predicted by the digital planning and actually implanted was 68.42% (13/19). ConclusionPreoperative digital planning can further optimize the acetabular reconstruction in THA for DDH.
Objective To investigate the effectiveness of absorbable pins for reconstructing pelvic stability in Salter innominate osteotomy for treating development dysplasia of the hip (DDH). Methods Between January 2003 and December 2008, 392 patients (440 hips) with DDH underwent a Salter procedure. There were 68 boys (82 hips) and 324 girls (358 hips) with a mean age of 3 years and 3 months (range, 1 year and 6 months-5 years). According to Tonnis classification criteria, 13 hips were rated as grade I, 304 hips as grade II, 82 hips as grade III, and 41 hips as grade IV. Based on the degree of displacement of the femoral head and acetabular index on the anteroposterior pelvic X-ray film, operation method was selected before operation. A total of 341 hips were managed with open reduction and Salter innominate osteotomy, and 99 hips with Salter innominate osteotomy and femoral shortening rotating osteotomy. All cases underwent autologous iliac crest grafting and fixation between osteotomy sites and bone graft with 2 absorbable pins. Results At 1 day after operation, anteroposterior pelvic X-ray examination showed concentric reduction in all hips, having no instability of the joint of the osteotomy sites or bone graft shifting. A total of 368 patients (413 hips) were followed up 1 to 7 years (mean, 3 years and 10 months). At 3 months after operation, no bone graft in stability or shift, and sliding or loosening of pins occurred. At last follow-up, concentric reduction rate was 100%; after hip loading, 358 patients had no claudication and limited hip activities, who had the stability of hips and negative Allis and Ortalani signs. No abnormal height growth was observed in all patients. According to Mckay’s hip function evaluation criteria, the results were excellent in 390 hips, good in 16 hips, and fair in 7 hips, with an excellent and good rate of 98.3%; according to Severin X-ray criteria, the results were excellent in 386 hips, good in 17 hips, and fair in 10 hips, with an excellent and good rate of 97.6%. Conclusion Absorbable pins can replace steel pins for fixation of the osteotomy sites and bone graft in Salter innoninate because of flexible and convenient operation without a need for reoperation of steel pins extraction.
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 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.
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.
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.
ObjectiveTo investigate the anatomical morphology of the proximal femur in adult patients with Crowe type IV developmental dysplasia of the hip (DDH) so as to provided a reference for the selection of femoral components or personalized artificial prosthesis for DDH. MethodsBetween June 2004 and December 2014, 49 patients (58 hips) with Crowe type IV DDH were included in this study. There were 7 males (8 hips) with an average age of 47.3 years and 42 females (50 hips) with an average age of 30.0 years. X-ray films were taken in all cases and CT scanning in 17 cases (17 hips). The anatomical parameters were measured through Osirix V 5.8.5 software. ResultsThe distance of femoral head dislocation was (6.09±1.04) cm;the femoral head and neck disappeared completely in 8 hips (13.8%);femoral head atrophy and deformation and femoral neck disappearance were observed in 11 hips (19.0%). The midpoint width of the small trochanteric canal was (1.53±0.29) cm;the isthmus diameter was (0.69±0.09) cm;the canal flare index (CFI) value was (3.50±0.42) cm;the femoral neck anteversion angle was (37.0±18.2)°;and all indexes showed significant difference when compared with ones of normal population and Crowe type I, II, and III patients. But there was no significant difference in femoral neck-shaft angle (132.3±9.1°), isthmus height (11.66±2.67) cm (P<0.05). The chimney type cavity (CFI<3) accounted for 51.7%, which was significantly higher than the value of normal population. There was a positive correlation between metaphyseal CFI and CFI (r=0.63, P=0.00), but there was no correlation between metaphyseal CFI and distal CFI (r=-0.17, P=0.21). ConclusionThe proximal femur has the morphological characteristics of narrow medullary cavity, increased anteversion angle, and high ratio of chimney type cavity, so it is necessary to design specialized femoral components or personalized artificial prosthesis for the DDH.
ObjectiveTo investigate the influence of the degree of acetabular deformity and the learning-curve on the acetabular cup positions in total hip arthroplasty (THA) for adults with developmental dysplasia of hip (DDH). MethodsBetween January 2008 and December 2015, 130 patients (144 hips) with DDH underwent primary THA, and the clinical data were analyzed retrospectively. Fifty-three patients (59 hips) were admitted before 2012, and 77 patients (85 hips) were treated after 2012. There were 32 males and 98 females, aged from 31 to 83 years (mean, 61). Unilateral replacement was performed in 116 cases and bilateral replacement in 14 cases. Of 144 hips, 48 hips were rated as Crowe type I, 57 hips as type II, and 39 hips as type of III/IV. The standard pelvic radiograph was taken within 1 week after operation. The mediCAD software was adopted to measure the angle of anteversion and abduction, bony coverage, and the distance between true rotating center and optimal rotating center to the connection of teardrops and the horizontal distance between two centers to evaluate the qualified rate of acetabular cup positions. ResultsCompared with the patients with the same type in 2013-2015 group, the anteversion angle and qualified rate of acetabular cup position significantly decreased in patients with Crowe I (P < 0.05); the horizontal distance significantly increased and qualified rate of acetabular cup position significantly decreased in patients with Crowe II (P < 0.05); and the anteversion angle significantly decreased and the horizontal distance significantly increased in patients with Crowe III/IV (P < 0.05) in 2008-2012 group. But no significant difference was shown in the other indexes (P > 0.05). In all Crowe types, the vertical distance between the true rotating center and the optimal rotating center increased with the degree of acetabular deformity in both 2008-2012 group and 2013-2015 group, showing significant difference (P < 0.05), but no significant difference was found in the other indexes (P > 0.05). ConclusionFor adults with acetabular dysplasia, there are high potential risks for unsatisfactory acetabular cup positions during primary THA. So it is necessary to evaluate acetabular deformities and to sum up operative experience so as to improve the accuracy of cups installation.
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 evaluate the early effectiveness and summarize the initial application experiences of Mako robot-assisted total hip arthroplasty (THA) for developmental dysplasia of the hip (DDH) in adults. Methods Between August 2018 and January 2020, 55 cases of DDH (75 hips) were treated with Mako robot-assisted THA. There were 10 males and 45 females with an average age of 51 years (range, 30-73 years). There were 35 cases of unilateral hip and 20 cases of bilateral hips. The DDH was classified as Crowe type Ⅰin 29 hips, type Ⅱ in 20 hips, type Ⅲ in 6 hips, and type Ⅳ in 20 hips. The modified Harris score was 54.8±16.0, the hip joint range of motion was 90° (80°, 100°), and the leg length discrepancy (LLD) was 22.0 (10.5, 47.0) mm. The preoperative surgical plan was made in the robot system based on the CT data. The reaming and installation of the acetabular cup were completed with the assistance of the robot system. The distance between the rotation center of the hip joint and the teardrop (horizontal distance, vertical distance), inclination angle, and anteversion angle were measured on the pelvic X-ray film to evaluate the position of the acetabular prosthesis. The above indicators were compared with preoperative planning to evaluate the accuracy of robotic-assisted surgery. The modified Harris score, the range of motion, and the LLD were used to evaluate the early effectiveness. Results The 75 hips of THAs were completed with the assistance of Mako robots. There was no significant difference in the acetabular inclination angle, the horizontal distance and the vertical distance of the rotation center between the preoperative planning and the postoperative measurement values (P>0.05); the acetabular anteversion angle was significantly smaller than the postoperative measurement value (t=–2.482, P=0.015). Four hips located beyond the Lewinnek safety zone, and 71 hips located within the Lewinnek safety zone. All patients followed up 6-24 months (mean, 13 months). All incisions healed by first intention. At last follow-up, the modified Harris score was 85.5±11.2, the hip joint range of motion was 120° (110°, 120°), and the LLD was 3.8 (2.0, 8.1) mm; all improved significantly compared with preoperative ones (P<0.05). Except for one nerve injury case, there was no other complication. Conclusion Mako robot-assisted THA is a safe and effective method for adult DDH, which can optimize the acetabular cup positioning, hip function, and leg length, but the long-term effectiveness needs to be confirmed by further studies.