Early patellar tendon rupture after total knee arthroplasty: A direct repair method

BACKGROUND Patellar tendon rupture after total knee arthroplasty(TKA)is a catastrophic complication.Although the occurrence of this injury is rare,it can lead to significant dysfunction for the patient and is very tricky to deal with.There has been no standard treatment for early patella tendon rupture after TKA,and long-term follow-up data are lacking.AIM To introduce a direct repair method for early patella tendon rupture following TKA and determine the clinical outcomes and complications of this method.METHODS During the period of 2008 to 2021,3265 consecutive TKAs were retrospectively reviewed.Twelve patients developed early patellar tendon rupture postoperatively and were treated by a direct repair method.Mean follow-up was 5.7 years.Demographic,operative,and clinical data were collected.The clinical outcomes were assessed using the Western Ontario and McMaster Universities(WOMAC)score,the Hospital for Special Surgery(HSS)score,knee range of motion,extensor lag,and surgical complications.Descriptive statistics and paired t test were employed to analyze the data.RESULTS For all 12 patients who underwent direct repair for early patellar tendon rupture,3 patients failed:One(8.3%)for infection and two(17.6%)for re-fracture.The two patients with re-fracture both underwent reoperation to reconstruct the extensor mechanism and the patient with infection underwent revision surgery.The range of motion was 109.2°±10.6°preoperatively to 87.9°±11°postoperatively,mean extensor lag was 21°at follow-up,and mean WOMAC and HSS scores were 65.8±30.9 and 60.3±21.7 points,respectively.CONCLUSION This direct repair method of early patellar tendon rupture is not an ideal therapy.It is actually ineffective for the recovery of knee joint function in patients,and is still associated with severe knee extension lag and high complication rates.Compared with the outcomes of other repair methods mentioned in the literature,this direct repair method shows poor clinical outcomes.

Reconstruction of Paprosky type ⅢB acetabular bone defects using a cup-on-cup technique: A surgical technique and case series

BACKGROUND Paprosky type ⅢB acetabular bone defects are very difficult to reconstruct.For severe defects,we developed our own cup-on-cup technique.We defined the tantalum metal (TM) revision shell with the peripheral titanium ring removed as a TM-cup augment and the cementless hemispherical acetabulum component combined with a TM-cup augment as the cup-on-cup technique.AIM To report the short-term results of patients with typeⅢB acetabular bone defects reconstructed using the cup-on-cup technique.METHODS We retrospectively reviewed six patients (six hips) with a mean age of 59 years who underwent acetabular reconstruction using our cup-on-cup technique between January 2015 and January 2017.All acetabular bone defects were classified as typeⅢB without pelvic discontinuity using the system of Paprosky All patients were followed both clinically and radiographically for a mean duration of 42 mo.RESULTS The mean Harris hip score improved from 32.4 pre-operatively to 80.7 at the last follow-up.The mean vertical position of the hip rotation centre changed from60.9 mm pre-operatively to 31.7 mm post-operatively,and the mean horizontal position changed from 33.6 mm pre-operatively to 38.9 mm post-operatively.Greater trochanteric migration after extended trochanteric osteotomy occurred in one of six hips at 3 mo.There was no evidence of component migration at the last follow-up.CONCLUSION The short-term results suggest that our cup-on-cup technique could beconsidered an effective management option for Paprosky type ⅢB acetabular bone defects without pelvic discontinuity.

Jumbo cup in hip joint renovation may cause the center of rotation to increase

BACKGROUND Utilizing the large jumbo cup in revision total hip arthroplasty is an effective approach to cure many lacunar and segmental peripheral bone defects.However,with the use of the jumbo cup,the center of the hip joint may become elevated relative to the primary acetabulum,and the diameter of the large cup is greater.AIM To study the height and the significance of the elevation of the hip joint center.METHODS Eighty-eight patients matched the criteria for this condition and were included in the study.The center height of the hip joint was measured relative to the opposite normal hip joint.The diameter of the jumbo cup was measured and checked according to operation notes,and the diameter of the jumbo cup was measured with a prosthesis label.Then,the horizontal and vertical centers of rotation were measured on the surgical side and opposite side.The average center height of the hip joint on the renovated side and the opposite side and the position of the hip cup relative to the teardrop were compared using a paired t-test.RESULTS Radiometric analysis showed that the average hip joint center was elevated by 7.6 mm.The rotational center height delta of the renovated hip was 7.6±5.6 mm,and there was an obvious difference between the two groups(P=0.00).The difference in horizontal distance was 0.5±5.1 mm(-11.5-14.0 mm),and there was no obvious difference between the two groups(P=0.38).According to the foreign standard,the rotational center height delta of the renovated hip was 7.5±6.2 mm,and there was a significant difference between the two groups(P=0.00).There was no obvious difference between the domestic and foreign standards(P>0.05)between the two groups.CONCLUSION The application of the jumbo cup elevates the rotational center of the hip joint,but it is feasible and effective to use the jumbo cup.

Re-revision surgery for re-recurrent valgus deformity after revision total knee arthroplasty in a patient with a severe valgus deformity: A case report

BACKGROUND A recurrent valgus deformity was a common complication after total knee arthroplasty(TKA)in patients with valgus deformity.However,re-revision surgery for re-recurrent valgus deformity after revision TKA in patients with valgus deformity before primary TKA was uncommon.CASE SUMMARY We reported a 72-year-old female patient with two recurrent valgus deformities after TKA for a valgus knee deformity who underwent two revision surgeries to rectify the deformity.In the re-revision surgery,bone defects were successfully reconstructed by the augments and cement in combination with screws and a sleeve.An appropriate neutral alignment of the lower limb was restored by the perfect femoral entry point and the long diaphyseal cementless stem.Adequate fixation of the metaphysis and diaphysis of the femur was obtained by the sleeve and long diaphyseal cementless stem.The patient was pain-free and deformityfree for 2.5 years.CONCLUSION The management of bone defects,the choice of the stem and the femoral entry point were of vital importance in the revision or re-revision TKA for a recurrent valgus deformity.

Different squatting positions after total knee arthroplasty: A retrospective study

BACKGROUND Total knee arthroplasty(TKA)has been shown to improve quality of life and reduce pain.High-flexion activities such as squatting,kneeling,and floor transfers are mainly listed as demanding tasks.Among them,squatting is an important position.AIM To provide a new squat position classification and evaluate the different squatting positions of a series of patients after primary TKA.METHODS From May 2018 to October 2019,we retrospectively reviewed 154 video recordings of the squatting-related motions of patients after TKA.Among the included patients,119 were women and 35 were men.Their mean age at the index surgery was 61.4 years(range,30 to 77).RESULTS The median follow-up was 12 mo(range,6 to 156 mo).We classified those squatting-related motions into three major variations according to squatting depth:Half squat,parallel squat,and deep squat.The angles of hip flexion,knee flexion,and ankle dorsiflexion were measured in the screenshots captured from the videos at the moment of squatting nadir.A total of 26 patients were classified as half squats,75 as parallel squats,and 53 as deep squats.The angles of hip flexion,knee flexion,and ankle dorsiflexion all differed significantly among the three squatting positions(P<0.001).In the parallel squat group,the mean knee flexion angle(°)was 116.5(SD,8.1;range,97 to 137).In the deep squat group,the mean knee flexion angle(°)was 132.5(SD,9.3;range,116 to 158).CONCLUSION Among the three squatting positions,deep squat showed the highest hip,knee,and ankle flexion angles,followed by the parallel squat.With the improvement of squatting ability,the patient's postoperative satisfaction rate was also significantly enhanced.However,the different squatting abilities of the patients cannot be effectively distinguished from the scoring results(P>0.05).Our squatting position classification offers a pragmatic approach to evaluating patients’squatting ability after TKA.