Monobloc radial head prostheses in complex elbow injuries: results after primary and secondary implantation

Purpose

Dislocations of components, loosening of the stem, overstuffing and removal in up to 24 % of common radial head prostheses (RHP) after implantation in complex elbow injuries signal the need for improvement. The latest biomechanical evidence shows advantages for monopolar designs. Clinical results after primary and secondary implantation of the newly designed press-fit monobloc monopolar RHP in cases of complex elbow injury are evaluated.

Methods

Twenty-nine patients [median age 60 years (29–86)] were followed up retrospectively for a median of 25 months (7–54) post-operatively. Subjective parameters, the Mayo Elbow Performance Score (MEPS), the Broberg and Morrey score (BMS), latest radiographs and complications were evaluated.

Results

MEPS and BMS averaged 87.2 ± 12.9 and 81.1 ± 11.9 points, respectively. No case of implant loosening was observed; the RHP had to be removed in one case (3 %). The overall complication and revision rate was higher after secondary (53 %) than after primary (19 %) implantation.

Conclusions

Satisfactory clinical results and low short-term removal rates emphasise the practicality of monobloc monopolar RHP. Differentiated treatment of complex elbow fracture-dislocations is compulsory to avoid the need for secondary RHP implantation which carries a higher complication rate.     

Radiographic interpretation of distal radius fractures: visual estimations versus digital measuring techniques

Purpose

Distal radius fractures are a common injury. In the emergency room, trainees regularly assess these fractures using visual estimation. Our hypothesis is that assessment of radiographic parameters has sufficient accuracy for rendering treatment consistent with formal measurements.

Methods

This study compared visual measurements made by 25 orthopaedic residents and attending physicians to formal measurements made by a single fellowship trained musculoskeletal radiologist in a series of patients with distal radius fractures. A search was performed utilizing the ICD-9 code for distal radius fracture in all patients presenting to a single institution emergency department. Participants used visual estimation to rate 25 radiographs. Parameters estimated included radial inclination, radial height, volar tilt, and the presence of intra-articular displacement. Analysis using Lin concordance coefficients, Bland Altman plots, and the Kappa statistic evaluated the agreement between visual estimation and formal measurements. The proportion of raters whose estimates would have resulted in a course of treatment that conflicted with the formal reading quantified the potential impact of visual estimation on treatment.

Results

Concordance coefficients were poor for radial inclination (ρc = 0.13), radial height (ρc = 0.24), and volar tilt (ρc = 0.46). The Kappa statistic for intra-articular displacement was 0.4. Analysis performed according to level of training did not result in substantial improvements in these statistics. Treatment based on visual estimates conflicted with formal readings 34 % of the time for radial inclination, 38 % of the time for radial height, 27 % of the time for volar tilt, and 31 % of the time for intra-articular displacement.

Discussion

Visual estimation is not an adequate form of measurement for evaluation of patients with distal radius fractures. Physicians should be mindful of these results when developing treatment plans based solely upon visual estimation.     

Radial head arthroplasty using a metatarsal osteochondral autograft

Purpose

Treatment of comminuted fractures of the radial head is controversial, and considerable effort has been made to restore optimal function of the elbows, either by surgical reconstruction or prosthetic replacement. This report presents our experiences in treatment of unreconstructable radial head or neck fractures using osteochondral autografts harvested from the base of the second metatarsal bones.

Methods

Five patients with radial head and one with a radial neck fracture underwent treatment with osteochondral autografts. After excision of the unreconstructable radial head, the second metatarsal base was harvested and transplanted to the radius using the intramedullary nailing technique.

Results

The reconstructed elbows were examined clinically and radiographically for a mean period of 44.8 months (range, 24–72 months). At the last follow-up, in flexion-extension, the mean elbow mobility was 130°/10°. In supination-pronation, the mean elbow mobility was 73.3°/66.7°, with a mean loss of supination of 19.2° and loss of pronation of 12.5°. Grip strength was 91%, compared with the contralateral limb. The mean Mayo Elbow Performance Score was 94.2. The mean score of AOFAS rating system to the lesser toe was 93.7 points.

Conclusion

Radial head arthroplasty with an osteochondral autograft from the second metatarsal base appears to be an effective alternative for treatment of unreconstructable radial head fractures. A larger group of patients and a longer follow-up period will be required in order to ease concerns regarding the donor site; however, none of the patients who underwent this procedure showed any complications during follow-up.     

Repair of segmental long-bone defects by stem cell concentrate augmented scaffolds: a clinical and positron emission tomography - computed tomography analysis

Purpose

Treating segmental long-bone defects remains a major challenge. For defects >3 cm, segmental transport represents the gold standard, even though the method is time consuming and afflicted with several complications. The aim of this study was to evaluate healing of such defects after grafting an osteogenic scaffold previously seeded with stem cell concentrate.

Methods

We evaluated five patients with segmental long-bone defects (3–14 cm) treated with bone marrow aspirate concentrates (BMAC) seeded onto a bovine xenogenous scaffold. The healing process was monitored by X-rays and positron emission tomography–computed tomography (PET-CT) three months after surgery.

Results

Centrifugation led to a concentration of leukocytes by factor 8.1 ± 7.5. Full weight bearing was achieved 11.3 ± 5.0 weeks after surgery. PET analysis showed an increased influx of fluoride by factor 8.3 ± 6.4 compared with the contralateral side (p < 0.01). Bone density in the cortical area was 75 ± 16 % of the contralateral side (p < 0.03). The patient with the largest defect sustained an implant failure in the distal femur and finally accomplished therapy by segmental transport. He also had the lowest uptake of fluoride of the patient collective (2.2-fold increase).

Conclusion

Stem cell concentrates can be an alternative to segmental bone transport. Further studies are needed to compare this method with autologous bone grafting and segmental transport.     

Evaluation of the accuracy of femoral component orientation by the CT-based fluoro-matched navigation system

Purpose

Accurate orientation of acetabular and femoral components are important during THA. However, no study has assessed the use of the CT-based fluoro-matched navigation system during THA. Therefore, we have evaluated the accuracy of stem orientation by CT-based fluoro-matched navigation.

Methods

The accuracy of stem orientation by CT-based fluoro-matched navigation was assessed by postoperative CT data. Furthermore, we compared the postoperative stem orientation with the intraoperative registration errors.

Results

The average antetorsion error of the stem (navigation records − postoperative CT) was −0.5° ± 5.2°. The stem valgus error was 0.4° ± 2.7°. The accuracy of the navigation record for the orientation of the stem valgus was dependent on the intraoperative registration errors.

Conclusions

The clinical accuracy of CT-based fluoro-matched navigation is adequate for stem alignment orientation, and the intraoperative verification of registration errors is valuable for checking the accuracy of stem orientation by navigation.     

Posterior acetabular arc angle of the femoral head assesses instability of posterior fracture-dislocation of the hip

Purpose

Unstable posterior fracture-dislocation of the hip is determined by the wall defect or acetabular fracture index. The unstable hip is a result of inadequate posterior acetabular coverage of the femoral head from the posterior acetabular wall fracture. In order to measure total posterior acetabular coverage of the femoral head and avoid using the contralateral acetabulum as a calculation reference, the posterior acetabular arc angle of the femoral head was measured to assess stability of posterior fracture-dislocation of the hip.

Methods

Using coronal computed tomography (CT) scan of the normal contralateral acetabulum at the level of the widest acetabular diameter and thinnest medial wall of 60 acetabular fractures, posterior acetabular arc angles of the femoral head in intact, 20 % and 50 % defects of posterior acetabular walls were measured. The angles were measured from the acetabular centre to the thinnest medial wall and to the top, inner cortex of 80 % and 50 % posterior acetabular walls.

Results

Average intact, 80 % and 50 % posterior acetabular walls were 33.82 ± 4.30, 26.88 ± 3.33 and 16.91 ± 2.15 mm which corresponded to 92.25 ± 11.34, 77.42 ± 10.04 and 50.63 ± 6.58° of posterior acetabular arc angles of the femoral head. The intraclass correlation coefficient (ICC) of the measurements including correlation of conversion of posterior acetabular wall depths to posterior acetabular arc angles of the femoral head were more than 0.82 and 0.89.

Conclusions

The measurement technique of posterior acetabular arc angle of the femoral head has strong reliability. Therefore, stable or unstable posterior fracture-dislocation of the hip can be determined in terms of more than 77 degrees or less than 50 degrees of posterior acetabular arc angles of the femoral head instead of less than 20 % or more than 50 % posterior acetabular wall defect.     

Osseointegration of polyethylene implants coated with titanium and biomimetically or electrochemically deposited hydroxyapatite in a rabbit model

Purpose

The aim of this study was to evaluate the osseointegration of a new coating directly deposited on PE at room temperature.

Methods

Thirty-six (36) male New Zealand rabbits were randomly assigned to receive one out of three types of implants: two tested implants, i.e. PE implant coated with TiPVD and biomimetic HA (biomimetic), PE implant coated with TiPVD and electrolytic HA (electrolytic), and positive control made of massive microrough titanium coated with plasma sprayed HA (TiHAPS). Osseointegration was evaluated by histomorphometry (bone tissue in contact [BIC]), mineralized bone area [MBA]) and mechanical testing (push-out test, interfacial shear strength [ISS]) at six and 12 weeks in the distal femurs.

Results

For BIC there were no differences between the groups at six (p = 0.98) and 12 weeks (p = 0.13). For MBA, no statistically significant difference was measured between groups at six (p = 0.52) and 12 weeks (p = 0.57). At six weeks, interfacial shear strength (ISS) was significantly higher (p = 0.01) for TiHAPs implants compared to biomimetic and electrolytic implants. This difference was not significant at 12 weeks (p = 0.92).

Conclusion

The osseointegration of biomimetic and electrolytic implants was equivalent to a positive control at 12 weeks.     

Influencing factors for the increased stem version compared to the native femur in cementless total hip arthroplasty

Purpose

Stem version is not always equivalent to femoral neck version (native version) in cementless total hip arthroplasty (THA). We therefore examined the discrepancy of version between the native femoral neck and stem using pre- and postoperative computed tomography (CT), the level of the femur where the canal version most closely fit the stem version, and the factors influencing version discrepancy between the native femoral neck and stem.

Methods

A total of 122 hips in 122 patients who underwent primary THA using a metaphyseal-fit stem through the postero-lateral approach were included. Pre- and postoperative CT images were utilized to measure native and stem version, and the version of the femoral canal at four levels relative to the lesser trochanter.

Results

The mean native and stem versions were 28.1 ± 11.0° and 38.0 ± 11.2°, respectively, revealing increased stem version with a mean difference of 9.8° (p < 0.0001). A total of 84 hips (68.9 %) revealed an increase in version greater than 5°. Femoral canal version at the level of the lesser trochanter most closely approximated that of stem version. Among the factors analysed, both univariate and multivariate analysis showed that greater degrees of native version and anterior stem tilt significantly reduced the version discrepancy between the native femoral neck and stem version.

Conclusions

Since a cementless stem has little version adjustability in the femoral canal, these findings are useful for surgeons in preoperative planning and to achieve proper component placement in THA.     

Does stem design influence component positioning in total hip arthroplasty using a minimal invasive posterolateral approach?

Purpose

Limited data exist for the reconstructive potential of short bone-preserving stems in THA using a minimal invasive posterolateral approach. Our study aim was to assess the effect of stem design on the reconstruction of hip offset and leg length in MIS posterolateral THA.

Methods

This retrospective consecutive single-surgeon study compares hip offset and leg length, as well as acetabular component positioning (cup anteversion; inclination) of 129 THAs with a cementless standard-length stem (Synergy®) and 143 THAs with a cementless short bone-preserving stem (Trilock®).

Results

In reference to the contralateral side, the mean difference in hip offset was 0.9 mm (p = 0.067) for the standard stem and 0.1 mm (p = 0.793) for the short stem, respectively. Leg-length discrepancy was 0.7 mm (Synergy®) and 0.9 mm (Trilock®), respectively. A total of 233 (86 %) acetabular components fell within the target zone for anteversion and inclination.

Conclusion

Accurate component positioning in MIS posterolateral approach THA is possible and is not influenced by the type of stem.     

Poorer survival after a primary implant during revision total knee arthroplasty

Purpose

Revision total knee arthroplasty (rTKA) is a complex procedure. Depending on the degree of ligament and bone damage, either primary or revision implants are used. The purpose of this study was to compare survival rates of primary implants with revision implants when used during rTKA.

Methods

A retrospective comparative study was conducted between 1998 and 2009 during which 69 rTKAs were performed on 65 patients. Most common indications for revision were infection (30 %), aseptic loosening (25 %) and wear/osteolysis (25 %). During rTKA, a primary implant was used in nine knees and a revision implant in 60.

Results

Survival of primary implants was 100 % at one year, 73 % [95 % confidence interval (CI) 41–100] at two years and 44 % (95 % CI 7–81) at five years. Survival of revision implants was 95 % (95 % CI 89–100) at one year, 92 % (95 % CI 84–99) at two years and 92 % (95 % CI 84–99) at five years. Primary implants had a significantly worse survival rate than revision implants when implanted during rTKA [P = 0.039 (hazard ratio = 4.56, 95 % CI 1.08–19.27)].

Conclusions

Based on these results, it has to be considered whether primary implants are even an option during rTKA.     

Hip resurfacing in patients under thirty years old: an attractive option for young and active patients

Purpose

Metal-on-metal hip resurfacing is offered as an alternative to traditional hip arthroplasty for young, active adults with advanced osteoarthritis. The concept of hip resurfacing is considered very attractive for this specific population (hard-on-hard bearing component with a large femoral head limiting the risk of dislocation, and allowing femoral bone stock preservation).

Methods

A prospective clinical trial was designed to investigate the outcome of hip resurfacing in young patients (under 30 years old). We studied 24 hips in 22 patients. Mean age at operation was 24.9 years (range 17.1–29.9). No patient was lost to follow-up.

Results

There was no revision at average follow-up of 50.6 months (44–59). Mean UCLA activity score improved from 5.5 (1–9) pre-operatively to 7.6 (1–10) postoperatively (p < 0.001). Mean Harris hip score increased from 43.9 (19–67) to 89.3 (55–100) (p < 0.001). Radiological analysis discerned no osteolysis and no implant migration.

Conclusion

The absence of short-term complications, such as mechanical failure or dislocation, is encouraging and leads us to think that mid-term results will be satisfactory. Moreover, the specific advantages of hip resurfacing (bone stock preservation, excellent stability, low risk of dislocation, large-diameter head) make the procedure a very attractive option for young subjects.     

Intramedullary repair device against volar plating in the reconstruction of extra-articular and simple articular distal radius fractures; a randomized pilot study

Purpose

This prospective randomized pilot study reports our institutional experience and early results using Sonoma Wrx (Sonoma Orthopedic Products, Santa Rosa, CA) in the treatment of extra-articular and simple intra-articular distal radius fractures.

Material and methods

A total of 64 patients, were enrolled in the study. They were considered eligible if they had; unstable extra-articular distal radius fractures and simple intra-articular distal radius fractures suitable for closed reduction (AO types; A2.2, A2.3, A3.1 C2.1, C2.2). Patients in group I received intramedullary fixation using the Sonoma Wrx® device and patients in group II received standard volar locking plate fixation. Radiographic criteria of acceptable healing were used for evaluation.

Results

Two groups were similar in terms of baseline characteristics. Mean time of operation was significantly shorter in Group 1 vs. in group 2 (36.81 ± 7.11 vs. 48.97 ± 5.9 minutes, p = 0.001). Time to healing of the fracture was not different between two groups (5.45 ± 1.09 vs. 5.70 ± 1.04 weeks for Group 1 vs. 2, respectively p = 0.36). Overall complications occurred in 9 patients in group 1 and in 15 patients in group 2 (p = 0.17). Follow-up was completed in all patients with a median time of 12 months and 13 months in group 1 and 2, respectively. On radiographic evaluation radial inclination, radial height and volar tilt were not significantly different between group 1 and 2, respectively. There were no significant differences between two groups in regard to wrist rotational degrees measured in last follow-up visit.

Conclusion

Sonoma Wrx Device is reliable and effective in terms of achieving satisfactory outcomes in treatment of distal radius fractures. It may be reasonable to use this device to prevent complications that are related to extensive soft tissue dissection.     

Pathogen-driven decision for implant retention in the management of infected total knee prostheses

Purpose

In prosthetic joint infections (PJIs) of the knee, debridement with implant retention is associated with a high risk of recurrence.

Methods

A single-centre cohort study was performed with extensive analysis of the literature covering 1980–2012.

Results

In 21 patients (mean age 80.4 years, 19 immunosuppressed), in association with 1.5–three months of antibiotic treatment, an attempt was made to salvage the prosthesis by open (11 patients) or arthroscopic (ten patients) debridement. After a mean follow-up of seven years (range four–20 years), patients were in remission in seven cases (33 %). Remission was achieved in 0 % of all methicillin-resistant Staphylococcus aureus (MRSA) infections (zero/three), in 0 % (zero/three) of methicillin-resistant coagulase-negative staphylococcal infections, in 29 % (two/seven) of methicillin-sensitive S. aureus infections and in 75 % (three/four) of infections due to streptococci. The literature review focused on implant preserving approaches yielded 599 cases with an overall success rate of 47 % (284/599) and significantly more remissions in streptococcal vs staphylococcal knee PJIs (43/54 vs 144/324; p < 0.01, odds ratio 4.9, 95 % confidence interval 2.4–10.9).

Conclusions

In addition to established indications for explantation such as implant loosening, sinus tract or methicillin resistance, the decision for debridement and retention of knee PJIs should also depend on the pathogen. Implant preservation is futile with methicillin-resistant staphylococci, but seems to be a valid option for streptococcal PJIs.     

The migration pattern of the Charnley femoral stem: a five-year follow-up RSA study in a well-functioning patient group

Background

Implant stability is considered vital to long-time implant survival in total hip arthroplasty (THA), since loose implants are reported to be a major cause of hip revision. There is an association between early implant micromotion and increased risk of revision. More implant-specific data are needed to establish acceptable levels of early implant movement.

Materials and methods

Thirty-five patients (36 hips) undergoing Charnley THA were followed with repeated clinical, radiographic, and radiostereometric analysis (RSA) over 5 years. Twenty-three patients attended 5 years postoperatively.

Results

The patient group was well functioning based on the radiological and clinical evaluations. The stems constantly moved up to 5 years postoperatively, with subsidence, retroversion, and varus tilt, based on the RSA.

Conclusion

Continuous movement of the Charnley stem was observed up to 5 years postoperatively in a well-functioning patient group. The migration data presented herein could be useful when defining acceptable migration limits for certain types of cemented femoral stems.     

Results of a French multicentre retrospective experience with four hundred and eighteen failed unicondylar knee arthroplasties

Purpose

By means of a multicentre retrospective study based on the failure of 418 aseptic unicondylar knee arthroplasties (UKA) our aims were to present the different types of revision procedure used in failed UKAs, to establish a clear operative strategy for each type of revision and to better define the indications for each type of revision.

Methods

Aseptic loosening was the principal cause of failure (n = 184, 44 %) of which 99 cases were isolated tibial loosening (23.5 % of the whole series and 54 % of all loosening), 25 were isolated femoral loosening (six and 13.6 %) and 60 were both femoral and tibial loosening (14.3 and 32.6 %). The next most common causes of failure were progression of arthritis (n = 56, 13.4 %), polyethylene wear (n = 53, 12.7 %), implant positioning errors (n = 26), technical difficulties (n = six) and implant failure (n = 16, 3.8 % of cases). Data collection was performed online using OrthoWave™ software (Aria, Bruay Labuissiere, France), which allows collection of all details of the primary and revision surgery to be recorded.

Results

A total of 426 revisions were performed; 371 patients underwent revision to a total knee arthroplasty (TKA) (87 %), 33 patients (7.7 %) were revised to an ipsilateral UKA, 11 (2.6 %) patients underwent contralateral UKA (ten) or patellofemoral arthroplasty (one) and 11 patients (2.6 %) underwent revision without any change in implants.

Conclusions

Before considering a revision procedure it is important to establish a definite cause of failure in order to select the most appropriate revision strategy. Revision to a TKA is by far the most common strategy for revision of failed UKA but by no means the only available option. Partial revisions either to an alternative ipsilateral UKA or contralateral UKA are viable less invasive techniques, which in carefully selected patients and in experienced hands warrant consideration.     

Primary stability of the Fitmore® stem: biomechanical comparison

Purpose

After clinical introduction of the Fitmore® stem (Zimmer), we noticed the formation of cortical hypertrophies in a few cases. We questioned whether (1) the primary stability or (2) load transfer of the Fitmore® stem differs from other stems unassociated with the formation of hypertrophies. We compared the Fitmore® stem to the well-established CLS® stem.

Methods

Four Fitmore® and four CLS® stems were implanted in eight synthetic femurs. A cyclic torque around the stem axis and a mediolateral cyclic torque were applied. Micromotions between stems and femurs were measured to classify the specific rotational implant stability and to analyse the bending behaviour of the stem.

Results

No statistical differences were found between the two stem designs with respect to their rotational stability (p = 0.82). For both stems, a proximal fixation was found. However, for the mediolateral bending behavior, we observed a significantly (p < 0.01) higher flexibility of the CLS® stem compared to the Fitmore® stem.

Conclusion

Hip stem implantation may induce remodelling of the periprosthetic bone structure. Considering the proximal fixation of both stems, rotational stability of the Fitmore® stem might not be a plausible explanation for clinically observed formation of hypertrophies. However, bending results support our hypothesis that the CLS® stem presumably closely follows the bending of the bone, whereas the shorter Fitmore® stem acts more rigidly. Stem rigidity and flexibility needs to be considered, as they may influence the load transfer at the implant–bone interface and thus possibly affect bone remodelling processes.     

Fatigue performance of angle-stable tibial nail interlocking screws

Purpose

Tibial nail interlocking screw failure often occurs during delayed fracture consolidation or at early weight bearing of nailed unstable fractures, in general when high implant stress could not be reduced by other means. Is there a biomechanical improvement in long-term performance of angle stable locking screws compared to conventional locking screws for distal locking of intramedullary tibial nails?

Methods

Surrogate bones of human tibiae were cut in the distal third and distal locking of the 10 mm intramedullary tibial nail was performed with either two angle stable locking screws or two conventional locking screws in the mediolateral plane. Six specimens per group were mechanically tested under quasi-static and cyclic axial loading with constantly increasing force.

Results

Angle stable locking screw constructs exhibited significantly higher stiffness values (7,809 N/mm ± 647, mean ± SD) than conventional locking screw constructs (6,614 N/mm ± 859, p = 0.025). Angle stable locking screw constructs provided a longer fatigue life, expressed in a significantly higher number of cycles to failure (187,200 ± 18,100) compared to conventional locking screw constructs (128,700 ± 7,000, p = 0.004).

Conclusion

Fatigue performance of locking screws can be ameliorated by the use of angle stable locking screws, being especially important if the nail acts as load carrier and an improved stability during fracture healing is needed.     

Patellar resurfacing as a second stage procedure for persistent anterior knee pain after primary total knee arthroplasty

Purpose

Knee pain after total knee arthroplasty may be caused by an unresurfaced patella. Secondary isolated resurfacing of the previously unresurfaced patella in total knee arthroplasty remains controversial. The aim of this retrospective study was to evaluate the outcome after patellar resurfacing as a second stage procedure.

Methods

The study included 22 patients (13 female/nine male) who underwent resurfacing of the patella with a mean follow-up of 61.8 ± 39.2 months. The mean age of the patients was 60 ± 9.7 years at the time of operation. The average period between total knee arthroplasty and patellar resurfacing was 26.3 ± 15.2 months. The patient’s subjective satisfaction was assessed by a custom-made questionnaire.

Results

The mean Knee Society Score improved significantly from 60.1 ± 8.3 to 77.0 ± 6.3 (p = 0.0063). The mean functional score also improved significantly from 42.7 ± 2.3 to 60.2 ± 3.9 (p = 0.001). Three patients (13.6%) needed further operative revision.

Conclusions

Although clinical scores showed significant improvement some patients continued to have pain and remained dissatisfied without detecting a specific reason. Further studies are needed to better elucidate the benefit of patellar resurfacing as second stage procedure.     

Correlation between groin pain and cup design of hip-resurfacing implants: a prospective study

Purpose

Cup design has been incriminated as the source of groin pain after hip resurfacing but has not been well described; thus, it was assessed in a prospective study looking at three implant types.

Methods

A group-match was done between three groups of hip resurfacing devices according to age, sex, body mass index, activity level, osteoarthritis aetiology and pre-operative scores.

Results

The global groin pain rate was 5.7 % at six months and 2.7 % at last follow-up. Groin pain rate was significantly different between the three groups (p = 0.004) and had a strong influence on the subjective results (p = 0.04). No groin pain emerged between six months and last follow-up. No clinical differences were noted in Harris hip score and Merle d’Aubigné-Postel score at last follow-up. However, the Oxford hip score and Devane activity score were significantly lower for cups with macrostructures.

Conclusion

The low groin pain rate in this prospective cohort was probably secondary to the specific surgical technique used and seems to be correlated with cup design. Macrostructures on the external part of the cup could be significantly harmful.     

How often is functional range of motion obtained by manipulation for stiff total knee arthroplasty?

Purpose

To evaluate how often manipulation under anesthesia (MUA) can achieve functional flexion ≥ 90 degrees and identify predictor for successful outcome of MUA for stiff total knee arthroplasty (TKA).

Methods

Demographic data, range of motion, and surgical and anesthetic information of 143 MUAs were retrospectively analyzed from 2000 to 2011.

Results

One-hundred thirty-six out of 143 patients (95 %) improved mean range of motion (ROM) from pre-MUA 62 ± 17° to final ROM 101 ± 21° (p < 0.001). Flexion ≥ 90 degrees was achieved in 74% (106/143) of patients. Regional anesthesia was identified as predictor of successful MUA outcome (p = 0.007, OR: 8.5, 95 % CI: 1.2-66.7).

Conclusions

Although the proportion of patients regaining flexion ≥ 90 degrees following MUA was less than those patients with simple overall ROM increase, the functional flexion ≥ 90 degrees was achieved in the vast majority of patients with stiff TKA following MUA.