Risk factors associated with non-union after triple pelvic osteotomy (Toennis and Kalchschmidt technique): a case-control study and review of the literature.

INTRODUCTION: Dysplasia of the hip is a well known cause of secondary osteoarthritis of the hip. The triple pelvic osteotomy (TPO), according to the technique described by Toennis and Kalchschmidt, is a well established procedure to address dysplasia of the hip joint. Non-unions after triple pelvic osteotomies are rare and can occur at each of these osteotomies. The literature is lacking in studies investigating larger group of patients with non-unions after triple pelvic osteotomy. The aim of this study is to evaluate risk factors leading to a non-union after triple pelvic osteotomy. METHODS: A total of 53 patients with a non-union after triple pelvic osteotomy were included in this retrospective case-control. In addition, we identified a cohort of randomly selected patients undergoing hardware removal after triple pelvic osteotomy ("union" group) but had not developed non-union as the control group. This control group underwent the same procedure by the same group of surgeons in the same time period. The variables obtained from the review of the two groups were analyzed using appropriate statistical methods including Bivariable Analysis (p < 0.005) and Multivariable logistic regression analysis (p < 0.015). RESULTS: We identified a total of 53 patients out of the 3269 who had undergone TPO and had developed a non-union. The control group consisted of 117 patients who did not experience a non-union. Bivariable analysis of basic demographic characteristics demonstrated that gender, BMI, smoking, preoperative CE angle and degree of surgical correction did not differ significantly between the groups. There was a statistically significant (p < 0.05) difference between age (31.5 ± 9.4 vs. 27.5 ± 9.0 in the non-union and union groups, respectively; p = < 0.001) and postoperative CE angle (34.4 ± 5.0 vs. 32.8 ± 3.5 in the non-union and union groups, respectively; p = 0.02). Multivariable analysis demonstrated that an age over 30 was significantly associated with non-union (p = 0.01, OR 2.6, 95% CI 1.3-5.3). CONCLUSION: Non-unions after TPO are rare. A higher age and higher degree of surgical correction might be associated risk factors for developing a non-union. Furthermore, smoking, obesity and previous hip surgeries might also contribute to developing a non-union after triple pelvic osteotomy.

Advances in fixation strength of reorienting rectangular triple pelvic innominate osteotomies - A biomechanical investigation of two screw fixation techniques.

BACKGROUND: Reorientating pelvic osteotomies are performed to prevent femoral-acetabular impingement or degenerative arthritis. A Toennis-Kalchschmidt triple pelvis innominate osteotomy is used in symptomatic patients. This study aimed to investigate the biomechanical behaviour of two different acetabular screw configurations for triple pelvis innominate osteotomy osteosynthesis. METHODS: Two screw-orientation techniques in rectangular os ilium osteotomy were compared by osteotomising 12 artificial hemipelvises with triple pelvis innominate osteotomy protocol (fragment reorientation: 10.5° inclination and 10.0° anteversion) and randomising them in 2 groups (n = 6) for implantation with three 4.5 mm screws. Bidirectional group had a bidirectional screw orientation and Monoaxial group had a monoaxial direction of all three screws through iliac crest. All specimens were tested under progressively increasing cyclic loading until failure. Group-wise comparisons of acetabular cup medialisation, anteversion and inclination were evaluated via motion tracking at cycles 250, 500, 750, 1000, 1250, 1500, 1750, 2000, 2250, and 2500. Failure was defined as reaching 5° inclination or 5° anteversion. FINDINGS: Acetabular cup medialisation (p ≤ 0.026), anteversion (p ≤ 0.021) and inclination (p ≤ 0.039) all increased significantly during testing in both groups. There were no significant differences for the group-wise comparisons at the cycle points defined in the methods (p ≥ 0.182). No significant differences were detected between groups for cycles to failure and failure load (p = 0.873). INTERPRETATION: Bidirectional screw alignment does not lead to significant advantages compared to pure monoaxial if all three axial screws are evenly distributed over the osteotomy geometry. The triple pelvis innominate osteotomy is susceptible to changes in anteversion, inclination and medialisation under partial weight-bearing. Cautious rehabilitation protocols are recommended.

Triple pelvic osteotomy as treatment for osteoarthritis secondary to developmental dysplasia of the hip.

Joint-preserving osteotomies are an established treatment for adult hip pain secondary to developmental dysplasia of the hip. However, their value for advanced osteoarthritis is unclear. Therefore this study addresses the question of long-term results of triple pelvic osteotomy in patients with second grade osteoarthritis. Thirty-two patients with second grade osteoarthritis secondary to developmental dysplasia of the hip before triple pelvic osteotomy were clinically and radiographically assessed 11.5 years postoperatively. Five patients required conversion to total hip replacement. Kaplan-Meier survivorship analysis predicted a survival rate of 85.3%. The mean Harris hip score increased significantly with more than 56% good or very good results. A preoperative BMI > 25 and Harris hip score < 70 resulted in worse outcome or early conversion into total hip arthroplasty. The results indicate that developmental dysplasia of the hip even in second grade osteoarthritis can be treated with triple pelvic osteotomy.

Long-term results after open reduction of developmental hip dislocation by an anterior approach lateral and medial of the iliopsoas muscle.

The technique of and especially the approach to open reduction of developmental dislocation of the hip are still a matter of discussion. The anterior approach, first lateral and then medial to the iliopsoas muscle, was described by Tonnis in 1978. A follow-up investigation to adulthood has now been performed. Eighty-seven children (118 hips) out of 105 children (83%) who underwent open reduction of developmental dislocation of the hip before the age of 4 years were reinvestigated 10-21 years after the operation. An anterior approach first lateral, then medial to the iliopsoas muscle was chosen, because this offers the best access to the joint. Additional operations including transiliac osteotomy for acetabuloplasty, shortening osteotomy, and femoral osteotomies were performed as necessary. In 92 (78%) of the 118 hips studied the CE angle exceeded 25 degrees and in 98 hips (83%) the VCA angle exceeded 25 degrees. Critical CE angles between 20 and 25 degrees were found in 14% of the hips, and critical VCA angles in 4%. Residual dysplasia (<20 degrees) was found in 8 and 13% of the hips, respectively. Avascular necrosis according to Hirohashi was observed after operation in grade 1 in 5.9% and grade 2 in 1.7%. No necrosis was found following shortening osteotomy of the proximal femur. The anterior approach, first lateral, then medial to the iliopsoas muscle, offers an optimal access to the medial parts of the joint with control of reduction, protects the vasculature of the femoral neck, and allows simultaneous postero-lateral capsulorrhaphy and pelvic osteotomies.

Dysplasia epiphysealis hemimelica (Trevor's disease) of the acetabulum.

Unphysiological joint stress leads to problems and subsequently to joint destruction. We report a rare case of dysplasia epiphysialis hemimelica (DEH) of the triradiate cartilage of the acetabulum. In addition to clinical symptoms, we point out the specific therapy and outcome of the afflicted child.