Long-term survival of the uncemented Balgrist total hip replacement cup

Purpose

The purpose of this study was to evaluate the long-term clinical and radiographic outcomes of the Balgrist total hip replacement cup.

Methods

We report the results of a retrospective review of 195 total hip prostheses with Balgrist cup implanted in 178 patients. There were 59 men and 119 women with a mean age at surgery of 52.3 years (range, 19–72). Cox regression was used to determine the influence of independent variables on the survivorship of the prosthesis.

Results

There were 117 (66 %) of 178 patients, and 131 (67 %) of 195 hips available for assessment at a mean follow-up of 17.4 years. A total of 21 patients (22 hips) were lost from follow-up (12 %). A total of 25 patients (27 hips) required some type of re-operation during the follow-up period. Eight of 27 re-operations (30 %) were directly caused by the Balgrist cup failure due to fatigue fracture of the metallic shell (n = 5; 19 %), polyethylene wear (n = 2; 7 %) and aseptic loosening (n = 1; 4 %). The mean polyethylene wear rate was 0.068 mm/year (range, 0.008–0.230; SD = 0.043). The risk of re-operation for any reason was decreased with dysplastic hip as a primary diagnosis (hazard ratio; HR = 0.250; 95 % CI 0.086–0.725) and with greater age at the time of surgery (HR = 0.923; 95 % CI 0.880–0.969). The 19-year survivorship with re-operation for any reason was 75.6 % (95 % CI 67.0–84.2). The 19-year survivorship with re-operation for the Balgrist cup failure was 90.5 % (95 % CI 83.4–97.6).

Conclusions

The Balgrist cup continues to provide excellent clinical and radiological outcomes. This is associated at least in part with a low polyethylene wear rate. The main reason for the Balgrist cup failure is fatigue fracture of the metallic shell.     

Meta-analysis of randomised controlled trials comparing unipolar with bipolar hemiarthroplasty for displaced femoral-neck fractures

Purpose

Unipolar and bipolar hemiarthroplasty (HA) are used to treat displaced femoral-neck fractures. However, which type is best for treating displaced femoral-neck fractures in elderly patients remains a subject for debate. Our aim was to review randomised controlled trials to establish which type provides superior clinical outcome for this patient population.

Methods

We searched PubMed, Embase and Cochrane Register of Controlled Trials databases and Web of Science for randomised controlled trials (RCTs) comparing unipolar with bipolar HA to treat femoral-neck fracture in the elderly. Risk ratios (RRs) and mean differences (MDs) from each trial were pooled using random-effects or fixed-effects models depending on study heterogeneity. Analysis was performed using RevMan5.2 from the Cochrane Collaboration.

Results

A total of 1,100 patients from nine studies were assessed in this meta-analysis. Results showed no significant differences in function score [MD = −0.14, 95% confidence interval (CI) −2.42–2.13], mortality (RR = 0.97, 95% CI 0.65–1.46), dislocation (RR = 1.33, 95 % CI 0.53–3.34), deep infection (RR = 0.79, 95 % CI 0.35–1.79), acetabular erosion (RR = 1.99, 95 % CI 0.61–6.52), operating time (MD = 2.14, 95 % CI −9.85 to14.14), blood loss (MD = 13.40, 95 % CI −49.60 to 76.39) and length of hospital stay (MD = 0.12, 95 % CI −0.49to0.73) between unipolar and bipolar HA.

Conclusions

Unipolar and bipolar HA achieved similar clinical outcomes in patients with displaced femoral-neck fractures.     

Common causes of failed unicompartmental knee arthroplasty: a single-centre analysis of four hundred and seventy one cases

Purpose

We performed this retrospective study to determine the main causes for early and late failures of unicompartmental knee arthroplasty (UKA).

Methods

Between January 2000 and March 2012, all patients treated for a failed medial UKA in the authors’ institution were retrospectively reviewed. A total of 471 patients were identified, and causes of failure were analysed based on the medical records and radiographs at the time of revision.

Results

The cohort included 161 males and 310 females, with a mean age of 67.7 years (range, 42–91 years; SD = 10.1) at the time of revision. The mean time from index arthroplasty to revision surgery was 6.1 years (range, 0.1–27.9 years; SD = 5.6). A total of 254 cases (53.9 %) failed within five years after primary implantation, and 108 cases (22.9 %) failed after ten years. The major reason for failure was the development of other compartment arthritis (39.5 %), followed by aseptic loosening (25.4 %).

Conclusions

Of importance, the mean time to failure after UKA was 6.1 years, with more than 50 % of failures occurring within the first five years postoperatively.     

Antirotation Pins Improve Stability of the Compress Limb Salvage Implant: A Biomechanical Study

Background

Limb salvage implants that rely on compliant compression osseointegration to achieve bone fixation may achieve longer survivorship rates compared with traditional cemented or press-fit stemmed implants; however, failures resulting from rotational instability have been reported. The effect of using antirotation pins on the rotational stability of the fixation has not been well studied.

Questions/purposes

We asked the following question: When tested in a cadaver model, does the use of antirotation pins increase the torque required to cause implant failure or rotation?

Methods

Thirty-two cadaver femurs were divided into four groups of eight femurs. We compared the torque to failure among groups containing zero, one, two, three, and four pins using a servohydraulic testing device.

Results

Adding antirotation pins increased the torque required to cause failure (R² = 0.77; p < 0.001). This increase was most notable in groups comparing zero pins with one pin (14 N-m, [95% CI, 10.9–17.1] versus 23 N-m, [95% CI 22.5–23.48]; p = 0.01) and two compared with three pins (29 N-m, [95% CI, 21.7–36.3] versus 42 N-m, [95% CI, 37.8–46.2]; p = 0.35).

Conclusions

It appears that the use of antirotation pins improves rotational stability of the compliant compression endoprosthesis. Although these findings need to be verified in a clinical study, the addition of antirotation pins may improve osteointegration and we have changed our practice to use a minimum of three antirotation pins when implanting this device.

Clinical Relevance

Improvements in implant technology and surgical techniques may lead to improved clinical outcomes and patient quality of life. Addition of antirotation pins appears to improve implant stability and may decrease the need for revision surgery.     

Dual mobility cup reduces dislocation and re-operation when used to treat displaced femoral neck fractures

Purpose

Total hip arthroplasty (THA) as primary treatment for displaced femoral neck fractures is controversial as THA is associated with higher rates of dislocation but lower rates of re-operation compared to hemiarthroplasty (HA). A dual mobility cup (DMC) design is associated with lower dislocation and re-operation rates in elective surgery. Is this also the case when used to treat displaced femoral neck fractures? The aim of this study is to compare rates of dislocation and re-operation of any kind following treatment for displaced femoral neck fractures with either bipolar HA or THA with DMC.

Methods

Two consecutive groups of patients treated for displaced femoral neck fractures at the Regional Hospital in Viborg in Denmark were included. In 2007–2008 171 patients (mean age 84.1 years) were treated with bipolar HA. In 2009–2010 175 patients (mean age 75.2 years) were treated with THA with DMC. Data regarding rates of dislocation and re-operation were obtained by retrospective review of medical records.

Results

We found a statistically significant difference regarding rates of dislocation and re-operation of any kind in favour of THA with DMC. Dislocation occurred in 25/171 patients [95 % confidence interval (CI) 9.3–19.9 %] treated with bipolar HA and 8/175 patients (95 % CI 1.5–7.7 %) treated with THA with DMC (p = 0.002). Re-operations were required in 32/171 patients (95 % CI 12.9–24.6 %) treated with bipolar HA and 16/175 patients (95 % CI 4.8–13.4 %) treated with THA with DMC (p = 0.01).

Conclusions

Our findings indicate that THA with DMC is superior to bipolar HA following treatment for displaced femoral neck fractures in regard to rates of dislocation and re-operation.     

Dual mobility acetabular component in revision total hip arthroplasty for persistent dislocation: no dislocations in 50 hips after 1–5 years

Background

A dual mobility cup has the theoretic potential to improve stability in primary total hip arthroplasty (THA) and mid-term cohort results are favorable. We hypothesized that use of a new-generation dual mobility cup in revision arthroplasty prevents dislocation in patients with a history of recurrent dislocation of the THA.

Materials and methods

We performed a retrospective cohort study of patients receiving an isolated acetabular revision with a dual mobility cup for recurrent dislocation of the prosthesis with a minimum follow-up of 1 year. Kaplan–Meier survival analyses were performed with dislocation as a primary endpoint and re-revision for any reason as a secondary endpoint.

Results

Forty-nine consecutive patients (50 hips) were included; none of the patients was lost to follow-up. The median follow-up was 29 months (range 12–66 months). Two patients died from unrelated causes. Survival after 56 months was 100 % based on dislocation and 93 % (95 % CI 79–98 %) based on re-revision for any reason. Radiologic analysis revealed no osteolysis or radiolucent lines around the acetabular component during the follow-up period.

Conclusion

The dual mobility cup is an efficient solution for instability of THA with a favorable implant survival at 56 months.

Level of evidence

Level 4, retrospective case series.     

Recurrence of Dislocation Following Total Hip Arthroplasty Revision Using Dual Mobility Cups Was Rare in 180 Hips Followed Over 7?Years

Background

Dual mobility (DM) cups of mobile polyethylene were introduced to prevent total hip arthroplasty (THA) dislocation, but no large series with this design to treat recurrent instability have been reported.

Purpose

Our retrospective investigation ascertained the efficiency of DM cups in correction of recurrent dislocation and assessed any adverse effects.

Methods

One hundred eighty THAs with recurrent instability were revised to DM cups in 180 patients (mean age, 67.4 ± 11.7 years; range, 19 to 92 years). Thirty-one patients (17.2%) underwent at least one earlier THA revision, and 15 (10.3%) incurred non-union of the greater trochanter. Of the initial group in 2009, 145 patients had completed evaluations which included assessment of the Harris Hip Score and a radiographic assessment at a mean follow-up of 7.7 ± 2.2 years (range, 4 to 14 years). The rate of survival was calculated considering any reason for revision as failure.

Results

At follow-up, Harris hip score was 83.9 ± 16.1 (range, 21 to 100). Dislocation of the large articulation occurred in seven hips (4.8%), and only two recurred (1.4%) (one requiring additional revision). In addition, two intra-prosthetic dislocations of the small articulation (1.4%) were observed and needed revision surgery. The large number of earlier surgeries and non-union of the greater trochanter were related to recurrent instability. Two cups (1.4%) showed signs of definite loosening; six (4.1%) presented signs of possible loosening. Twenty-nine hips manifested femoral or acetabular osteolysis (20%), but only three were severe. Eight-year survival rate considering revision for any reason was 92.6% (95% CI, 85.5–96.4%).

Conclusions

This series indicates that DM cups are a viable option to treat recurrent THA instability. Their design provides a low risk of recurrent instability without increasing mechanical complications.     

Constraint choice in revision knee arthroplasty

Purpose

Along with the increase in primary total knee arthroplasty, there has been an increase in the number of revisions. The aim of this study was to propose a selection algorithm for the knee revision constraint according to the state of ligaments and to the bone defects Anderson Orthopaedic Research Institute Classification [AORI] classification. The hypothesis was that this algorithm would facilitate the appropriate choice of prosthesis constraint, thus providing stable components and a good long-term survivorship of the knee revisions.

Methods

Sixty consecutive revision knee arthroplasties in 57 patients were prospectively evaluated. Prostheses implanted at revision included postero-stabilised, condylar constrained and rotating hinged, relative to the state of the ligaments and of the bone loss around the knee. The median follow-up was nine years (range, 4–12).

Results

The median IKS knee and function scores and HSS score were 41 (15–62), 21.5 (12–43) and 34 (23–65) points, respectively, before the operation, and 81 (48–97), 79 (56–92) and 83.5 (62–98) points (p < 0.001) at the latest follow-up evaluation. The median ROM increased from 74° (29–110°) preoperatively to 121° (98–132°) (p < 0.01) at the final follow-up. Re-revision was necessary in five (8.3 %) patients.

Conclusions

A selection algorithm for the revision implant constraint based on the state of ligaments and the bone loss AORI classification could provide stable knee reconstructions and long-term success of knee revisions.     

Bone mineral density changes of the proximal tibia after revision total knee arthroplasty. A randomised study with the use of porous tantalum metaphyseal cones

Purpose

Forty patients were enrolled in a prospective randomised study using conventional method or “Trabecular Metal Cone” (TM Cone) (Zimmer inc., Warsaw, USA) for reconstruction of bone loss of the proximal tibia during revision total knee arthroplasty (rTKA). The aim was to evaluate changes in bone mineral density (BMD) at the proximal tibia.

Material and methods

Thirty-six patients [median 67 years (range: 40–85 years)] received rTKA with NexGen® (Zimmer Warsaw, USA) revision system. Knee Society´s Knee Scoring System and the Anderson Orthopaedic Research Institute (AORI) bone classification was used. Changes in BMD were measured by dual energy X-ray absorptiometry (DEXA).

Results

Knee and function score improved in both groups. No significant changes between the groups were found. Changes in BMD within the two groups were quite similar. Overall decreases in BMD of 0.1 - 5.4 % were found in both groups (ROI 1–6) postoperative to 12 months of follow-up, except that ROI 7 showed an increase in BMD (0.8 - 1.3 %). After 24 months of follow-up, an increase in BMD was found along the stem (ROI 2–5) of 1.9 - 6.3 % , with significant changes in the TM Cone Group (ROI 3, 4, 5) . No significant changes in BMD between the groups were found.

Conclusions

The bone remodelling pattern was almost the same in the two groups after two years.     

Radiographic quantification of dynamic hip screw migration

Purpose

This study aimed to propose a technique to quantify dynamic hip screw (DHS®) migration on serial anteroposterior (AP) radiographs by accounting for femoral rotation and flexion.

Methods

Femoral rotation and flexion were estimated using radiographic projections of the DHS® plate thickness and length, respectively. The method accuracy was evaluated using a synthetic femur fixed with a DHS® and positioned at pre-defined rotation and flexion settings. Standardised measurements of DHS® migration were trigonometrically adjusted for femoral rotation and flexion, and compared with unadjusted estimates in 34 patients.

Results

The mean difference between the estimated and true femoral rotation and flexion values was 1.3° (95 % CI 0.9–1.7°) and −3.0° (95 % CI – 4.2° to −1.9°), respectively. Adjusted measurements of DHS® migration were significantly larger than unadjusted measurements (p = 0.045).

Conclusion

The presented method allows quantification of DHS® migration with adequate bias correction due to femoral rotation and flexion.

Electronic supplementary material

The online version of this article (doi:10.1007/s00264-013-2146-4) contains supplementary material, which is available to authorised users.     

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.     

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.     

The natural history of unexplained early poor function following total hip replacement

Purpose

The majority of patients experience a significant improvement in quality of life and function after total hip replacement (THR). It has recently been shown that age and good pre-operative function are the best predictors of postoperative function. When patients fail to achieve a satisfactory outcome, a cause is often identified. Where there is no identifiable cause, advice, follow-up and management is not clear. The aim of this study was to determine the long-term outcome of patients who had early poor function, but no identifiable cause.

Methods

From a regional database, we identified 1,564 patients who underwent unilateral THR between 1998 and 2004 and who were without complication or subsequent bilateral procedure at six months. These patients were divided into two groups according to their Harris hip score (HHS) at this stage: group A consisted of 270 patients with a ‘poor’ result (HHS less than 70). Group B consisted of 1,294 patients with a ‘good’ or ‘excellent’ result (HHS 70 or above). The patients were reviewed at five years. One hundred and ten patients from group A and 980 from group B completed five-year follow-up without further identifiable complication.

Results

Those with poor or fair function at six months were at an increased risk of developing an identified complication by five years including dislocation (OR 5.7, 95 % CI 1.8–18.2), deep infection (OR 9.8, 95%CI 2.9–37.7) and death (OR 1.6, 95 % CI 1.1–2.3). There was a greater rate of revision in group A versus group B (OR 5.7, 95 % CI 2.9–11). The overall function measured by the Harris hip score significantly improved in group A, but never reached that of those with good or excellent function at six months (HHS 76.2 versus 90.3, P < 0.001).

Conclusions

Patients with poor function at six months, but no obvious cause, are at higher risk of developing complications by five years. This group may benefit from more regular arthroplasty review and intervention.     

Risk factors for dislocation arthropathy after Latarjet procedure: a long-term study

Purpose

The purpose of this study was to analyse the long-term incidence of dislocation arthropathy after a modified Latarjet procedure for glenohumeral instability.

Methods

Long-term follow-up information was obtained from a consecutive series of patients who had undergone a modified Latarjet procedure by one surgeon between 1986 and 1999. Multivariable regression analysis was performed to examine the relation between the development of a dislocation arthropathy and patients and surgery-related factors.

Results

There were 117 patients (117 shoulders) for evaluation, (35 women and 82 men) with a mean age 28.4 ± 8.5 (range, 16–55). The mean follow-up was 16.2 years (range, ten to 22.2 years). Signs of dislocation arthropathy were found in 36 % of patients, graded as Samilson 1 in 30 %, Samilson 2 in 3 %, and 3 % Samilson 3 in 3 % of patients. Risk factors for dislocation arthropathy included surgery in patients older than 40 years of age (64.3 vs. 34.4 %; adjusted RR 2.2, 95 % CI 1.7–2.9) and lateral positioning of the transferred coracoid process in relation to the glenoid rim (82.4 vs. 30.4 %; adjusted RR 2.3, 95 % CI 1.7–3.2). Patients with hyperlaxity developed less dislocation arthropathy (15 vs. 42.5 %; adjusted RR 0.4, 95 % CI 0.1–0.95).

Conclusion

The development of dislocation arthropathy after the Latarjet procedure remains a source of concern in the long term. It correlates with surgery after the age of 40 and lateral coracoid transfer in relation to the glenoid rim. On the other hand, hyperlaxity seems to have a protective effect on the development of dislocation arthropathy.     

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.     

Loss of Cement-bone Interlock in Retrieved Tibial Components from Total Knee Arthroplasties

Background

Aseptic loosening continues to be a short- and long-term complication for patients with cemented TKAs. Most studies to this point have evaluated tibial component fixation via radiographic changes at the implant-bone interface and quantification of component migration; direct assessment of morphologic features of the interface from functioning TKAs may provide new information regarding how TKAs function and are fixed to bone.

Questions/purposes

In a postmortem retrieval study, we asked: (1) What are the morphologic features at the cement-trabecular bone interface in retrieved tibial components? (2) Do constructs with greater time in service have less cement-trabecular bone interlock? (3) Do constructs with more estimated initial interlock sustain more interlock with in vivo service?

Methods

Fourteen postmortem retrieved tibial components with time in service from 0 to 20 years were sectioned and imaged at high resolution, and the current contact fraction, estimated initial interdigitation depth, current interdigitation depth, and loss of interdigitation depth were quantified at the cement-bone interface. Estimated initial interdigitation depth was calculated from the initial mold shape of the cement mantle that forms around the individual trabeculae at the time of surgery. Loss of interdigitation depth was the difference between the initial and current interdigitation depth.

Results

There was resorption of trabeculae that initially interlocked with the cement in the postmortem retrievals as evidenced by the differences between current interdigitation and the estimated original interdigitation. The current contact fraction (r² = 0.54; p = 0.0027) and current interdigitation depth (r² = 0.33; p = 0.033) were less for constructs with longer time in service. The current contact fraction for implants with 10 or more years in service (6.2%; 95% CI, 4.7%–7.7%) was much less than implants with less than 10 years in service (22.9%; 95% CI, 8.9%–37%). Similarly, the current interdigitation depth for implants with 10 or more years in service (0.4 mm; 95% CI, 0.27–0.53 mm) was much less than implants with less than 10 years in service (1.13 mm; 95% CI, 0.48–1.78 mm). The loss of interdigitation depth had a strong positive relationship with time in service (r² = 0.74; p < 0.001). Using a two-parameter regression model, constructs with more initial interdigitation depth had greater current interdigitation depth (p = 0.011), but constructs with more time in service also had less current interdigitation depth (p = 0.008).

Conclusions

The cement-trabecular bone interlock obtained initially appears to diminish with time with in vivo service by resorption of the trabeculae in the cement interlock region.

Clinical Relevance

Our study supports the surgical concept of obtaining sufficient initial cement interlock (approximately 3 mm), with the acknowledgment that there will be loss of interlock with time with in vivo service.     

Incidence of metacarpal fractures in the US population

Background

There are scarce data regarding the epidemiology of metacarpal fractures within the US population. The purpose of this study is to report the epidemiology of metacarpal fractures in the USA using the National Electronic Injury Surveillance System Database (NEISS).

Methods

The NEISS database represents a national probability sample of approximately 100 hospitals in the USA and its territories. The database was queried for metacarpal fractures during the time period 2002–2006. US census data were used to calculate incidence rate (IR) for various demographic criteria.

Results

A total of 4,718 metacarpal fractures were identified, representing approximately 160,790 metacarpal fractures. The calculated IR was 13.6 (95 % CI, 13.6–13.67) per 100,000 person-years. The highest IR occurred in the 10–19 age group (IR 38.8; 95 % CI, 38.6–38.9) followed by those 20–29 years of age (IR 28.4; 95 % CI, 28.3–28.5). Metacarpal fractures were found more commonly in males (IR 23; 95 % CI, 22.9–23.1) than females (IR 4.5; 95 % CI, 4.5–4.5), with an incidence rate ratio of 5.08. The most common mechanisms of injury were contact with a wall or door, and falls. The most common setting was in the home, followed by recreational locations.

Conclusions

The estimated incidence of metacarpal fractures presenting for acute hospital care in the USA is 13.6 per 100,000 person-years. Males in the second and third decades of life sustain this injury most commonly. Metacarpal fractures occur frequently in the home or recreational setting, with contact force as the primary mechanism of injury.     

Reoperation after lumbar disc surgery in two hundred and seven patients

Purpose

The purpose of this study was to compare the causes and characteristics of reoperations after different primary operations for lumbar disc herniation (LDH).

Methods

Out of a series of 5,280 patients who underwent operations for LDH between 2001 and 2012, 207 patients (135 male and 72 female, mean age 47.7 years) underwent primary and revision operations, which were included in this study. The following clinical parameters were retrospectively assessed: the primary surgical methods, the intervals between primary and revision operations, and surgical findings in the revisions.

Results

In total, 232 lumbar discs underwent reoperations. One hundred and nineteen reoperations were performed after microendoscopic discectomy (MED group), 68 after percutaneous endoscopic lumbar discectomy (PELD group) and 45 after open disc surgery (open group). The locations of revision operations had priority over those of primary surgery, with a moderate correlation (kappa coefficient = 0.533). A total of 46.6 % of reoperations were performed within 0.5 years after primary surgery, and 35.3 % were performed between one and five years. Real recurrent herniation (homolateral herniations at the same level) was significantly more common than other reoperative surgical findings (70.6 % in PELD group, 47.1 % in MED group, 37.8 % in open group). The overall mean interval until revision surgery was 18.9 months (8.1 months in the PELD group vs. 19.7 months in the MED group vs. 33.1 months in the open group, p < 0.01).

Conclusions

For LDH, real recurrent herniation was the most common cause of reoperations, and more reoperations for real recurrent herniations and shorter intervals were found after minimally invasive endoscopic discectomy than after open disc surgery.