The learning curve of the direct anterior approach is 100 cases: an analysis based on 15,875 total hip arthroplasties in the Dutch Arthroplasty Register.

BACKGROUND AND PURPOSE: In the last decade, the direct anterior approach (DAA) for total hip arthroplasty (THA) has become more popular in the Netherlands. Therefore, we investigated the learning curve and survival rate of the DAA in primary THA, using data from the Dutch Arthroplasty Register (LROI). PATIENTS AND METHODS: We identified all patients who received a primary THA using the DAA in several high-volume centers in the Netherlands between 2007 and 2019 (n = 15,903). Procedures were ordered per surgeon, using date of operation. Using the procedure number, operations were divided into 6 groups based on the number of previous procedures per surgeon (first 25, 26-50, 51-100, 101-150, 151-200, > 200). Data from different surgeons in different hospitals was pooled together. Revision rates were calculated using a multilevel time-to-event analysis. RESULTS: Patients operated on in group 1-25 (hazard ratio [HR] 1.6; 95% CI 1.1-2.4) and 26-50 (HR 1.6; CI 1.1-2.5) had a higher risk for revision compared with patients operated on in group > 200 THAs. Between 50 and 100 procedures the revision risk was increased (HR 1.3; CI 0.9-1.9), albeit not statistically significant. From 100 procedures onwards the HR for revision was respectively 1.0 (CI 0.6-1.6) and 0.8 (CI 0.5-1.4) for patients in operation groups 101-150 and 151-200. Main reasons for revision were loosening of the stem (29%), periprosthetic infection (19%), and dislocation (16%). INTERPRETATION: We found a 64% increased risk of revision for patients undergoing THA using the DAA for the first 50 cases per surgeon. Between 50 and 100 cases, this risk was 30% increased, but not statistically significant. From 100 cases onwards, a steady state had been reached in revision rate. The learning curve for DAA therefore is around 100 cases.

Osteoarthritis treatment using autologous conditioned serum after placebo.

BACKGROUND AND PURPOSE: Autologous conditioned serum (ACS) is a disease-modifying drug for treatment of knee osteoarthritis, and modest superiority over placebo was reported in an earlier randomized controlled trial (RCT). We hypothesized that when given the opportunity, placebo-treated patients from that RCT would now opt for ACS treatment, which would result in a greater clinical improvement than placebo. METHODS: Of 74 patients treated with placebo in the previous trial, 20 opted for ACS treatment. Patients who did not choose further treatment were interviewed about their reasons. Clinical improvement of the 20 ACS-treated patients was measured using knee-specific clinical scores, as was "response shift" at 3 and 12 months. RESULTS: In the 20 patients who did opt for ACS, the visual analog scale (VAS) score for pain improved; but after 12 months, clinical results were similar to those after placebo treatment. Response shift measurement demonstrated that the 20 patients had adapted to their disabilities during treatment. INTERPRETATION: Placebo-treated patients from an earlier trial were reluctant to undergo ACS treatment, in part due to the laborious nature of the therapy. In a subset of patients who opted for treatment, ACS treatment after placebo did not result in greater clinical improvement than placebo treatment only. However, due to the limited power of the current study and possible selection bias, definite advice on using or refraining from ACS cannot be given.

Prosthetic Joint Infection and Wound Leakage After the Introduction of Intraoperative Wound Irrigation With a Chlorhexidine-Cetrimide Solution: A Large-Scale Before-After Study.

Background: Intraoperative chlorhexidine irrigation could be a valuable additive to systemic antibiotics to prevent infections after total joint arthroplasties. However, it may cause cytotoxicity and impair wound healing. This study evaluates the incidence of infection and wound leakage before and after the introduction of intraoperative chlorhexidine lavage. Methods: All 4453 patients receiving a primary hip or knee prosthesis between 2007 and 2013 in our hospital were retrospectively included. They all underwent intraoperative lavage before wound closure. Initially, wound irrigation with 0.9% NaCl was standard care (n = 2271). In 2008, additional irrigation with a chlorhexidine-cetrimide (CC) solution was gradually introduced (n = 2182). Data on the incidence of prosthetic joint infections and wound leakage, as well as relevant baseline and surgical characteristics, were derived from medical charts. Chi-square analysis was used to compare the incidence of infection and wound leakage between patients with and without CC irrigation. Multivariable logistic regression was used to assess robustness of these effects by adjusting for potential confounders. Results: The prosthetic infection rate was 2.2% in the group without CC irrigation vs 1.3% in the group with CC irrigation (P = .021). Wound leakage occurred in 15.6% of the group without CC irrigation and in 18.8% of the group with CC irrigation (P = .004). However, multivariable analyses showed that both findings were likely due to confounding variables, rather than by the change in intraoperative CC irrigation. Conclusions: Intraoperative wound irrigation using a CC solution does not seem to affect the risk of prosthetic joint infection or wound leakage. Observational data easily yield misleading results, so prospective randomized studies are needed to verify causal inference. Level of Evidence: Level III-uncontrolled before and after the study.

PTH decreases in vitro human cartilage regeneration without affecting hypertrophic differentiation.

Regenerated cartilage formed after Autologous Chondrocyte Implantation may be of suboptimal quality due to postulated hypertrophic changes. Parathyroid hormone-related peptide, containing the parathyroid hormone sequence (PTHrP 1-34), enhances cartilage growth during development and inhibits hypertrophic differentiation of mesenchymal stromal cells (MSCs) and growth plate chondrocytes. This study aims to determine the possible anabolic and/or hypertrophic effect of PTH on human articular chondrocytes. Healthy human articular cartilage-derived chondrocytes (n = 6 donors) were cultured on type II collagen-coated transwells with/without 0.1 or 1.0 µM PTH from day 0, 9, or 21 until the end of culture (day 28). Extracellular matrix production, (pre)hypertrophy and PTH signaling were assessed by RT-qPCR and/or immunohistochemistry for collagen type I, II, X, RUNX2, MMP13, PTHR1 and IHH and by determining glycosaminoglycan production and DNA content. The Bern score assessed cartilage quality by histology. Regardless of the concentration and initiation of supplementation, PTH treatment significantly decreased DNA and glycosaminoglycan content and reduced the Bern score compared with controls. Type I collagen deposition was increased, whereas PTHR1 expression and type II collagen deposition were decreased by PTH supplementation. Expression of the (pre)hypertrophic markers MMP13, RUNX2, IHH and type X collagen were not affected by PTH. In conclusion, PTH supplementation to healthy human articular chondrocytes did not affect hypertrophic differentiation, but negatively influenced cartilage quality, the tissues' extracellular matrix and cell content. Although PTH may be an effective inhibitor of hypertrophic differentiation in MSC-based cartilage repair, care may be warranted in applying accessory PTH treatment due to its effects on articular chondrocytes.

Knee joint instability after total knee replacement in a patient with Ehlers-Danlos syndrome: the role of insert changes as practical solution.

Treatment of knee joint instability in patients with hypermobile Ehlers-Danlos syndrome (EDS) can be challenging. A 53-year-old woman with hypermobile EDS underwent bilateral total knee replacement (TKR) due to valgus osteoarthritis. During follow-up, she developed hypermobility of both knee replacements. Revision of the insert resolved the issue in her left knee; however, the right TKR required two insert exchanges and unfortunately instability persisted. Therefore, a revision to a constrained prosthesis was performed. Insert exchanges in an unstable TKR can give short-term benefits, but for the long-term, we would recommend a constrained prosthesis.

Isolated ulnopalmar dislocation of the fifth carpometacarpal joint.

Dislocations of the carpometacarpal (CMC) joints are uncommon and are frequently missed on standard radiographs of the hand. Dislocations could be dorsal or palmar; dorsal dislocations are seen more frequently. Palmar dislocations can be either ulnopalmar or radiopalmar. Stable CMC dislocations could be successfully treated conservatively, while unstable dislocations are mostly treated operatively. The purpose of this report is to present a patient with an isolated ulnopalmar dislocation of the fifth CMC joint, satisfactorily treated with closed reduction and casting.

Treatment of diaphyseal fractures of the humerus using a functional brace.

OBJECTIVE: To determine humeral diaphyseal fractures at risk for nonunion with functional brace treatment. DESIGN: Retrospective case series. SETTING: A single surgeon's practice. PATIENTS: Forty-nine of 52 consecutive patients treated nonoperatively for an isolated diaphyseal fracture of the humerus during a 6-year period were followed until either union and full or near-full restoration of shoulder and elbow motion, or until 6 months had passed, or until a reconstructive surgery was performed (average follow-up 14 months; range 2 to 50 months). INTERVENTION: Functional fracture brace. MAIN OUTCOME MEASUREMENTS: Radiographic and clinical union. RESULTS: Union was achieved in 44 of 49 patients (90%) with no more than 15-degree loss of shoulder or elbow motion in any patient. Four of 14 proximal-third fractures (29%), one of 22 middle-third fractures (4%), and none of the 13 distal-third fractures failed to heal. CONCLUSIONS: Proximal-third long oblique fractures may be at greater than average risk for nonunion after functional fracture bracing. LEVEL OF EVIDENCE: Level IV (case series).

Effect of collagen type I or type II on chondrogenesis by cultured human articular chondrocytes.

INTRODUCTION: Current cartilage repair procedures using autologous chondrocytes rely on a variety of carriers for implantation. Collagen types I and II are frequently used and valuable properties of both were shown earlier in vitro, although a preference for either was not demonstrated. Recently, however, fibrillar collagens were shown to promote cartilage degradation. The goal of this study was to evaluate the effects of collagen type I and type II coating on chondrogenic properties of in vitro cultured human chondrocytes, and to investigate if collagen-mediated cartilage degradation occurs. METHODS: Human chondrocytes of eight healthy cartilage donors were isolated, expanded, and cultured on culture well inserts coated with either collagen type I, type II, or no coating (control). After 28 days of redifferentiation culture, safranin O and immunohistochemical staining for collagen types I, II, X, and Runx2/Cbfa1 were performed and glycosaminoglycan (GAG) and DNA content and release were examined. Further, expression of collagen type I, type II, type X, MMP13, Runx2/Cbfa1, DDR2, α2 and ß1 integrin were examined by reverse transcriptase-polymerase chain reaction. RESULTS: The matrix, created by chondrocytes grown on collagen type I- and II-coated membranes, resembled cartilage more than when grown on noncoated membranes as reflected by histological scoring. Immunohistochemical staining did not differ between the conditions. GAG content as well as GAG/DNA were higher for collagen type II-coated cartilage constructs than control. GAG release was also higher on collagen type I- and II-coated constructs. Expression of collagen type X was higher of chondrocytes grown on collagen type II compared to controls, but no collagen X protein could be demonstrated by immunohistochemistry. No effects of collagen coating on DDR2 nor MMP-13 gene expression were found. No differences were observed between collagen types I and II. CONCLUSION: Chondrocyte culture on collagen type I or II promotes more active matrix production and turnover. No significant differences between collagen types I and II were observed, nor were hypertrophic changes more evident in either condition. The use of collagen type I or II coating for in vitro models, thus, seems a sound basis for in vivo repair procedures.

Interleukin-6 is elevated in synovial fluid of patients with focal cartilage defects and stimulates cartilage matrix production in an in vitro regeneration model.

INTRODUCTION: This study aimed to determine whether, as in osteoarthritis, increased levels of interleukin-6 (IL-6) are present in the synovial fluid of patients with symptomatic cartilage defects and whether this IL-6 affects cartilage regeneration as well as the cartilage in the degenerated knee. METHODS: IL-6 concentrations were determined by ELISA in synovial fluid and in conditioned media of chondrocytes regenerating cartilage. Chondrocytes were obtained from donors with symptomatic cartilage defects, healthy and osteoarthritic donors. The effect of IL-6 on cartilage regeneration and on metabolism of the resident cartilage in the knee was studied by both inhibition of endogenous IL-6 and addition of IL-6, in a regeneration model and in osteoarthritic explants in the presence of synovial fluid, respectively. Readout parameters were DNA and glycosaminoglycan (GAG) content and release. Differences between controls and IL-6 blocked or supplemented samples were determined by univariate analysis of variance using a randomized block design. RESULTS: Synovial fluid of patients with symptomatic cartilage defects contained more IL-6 than synovial fluid of healthy donors (P = 0.001) and did not differ from osteoarthritic donors. IL-6 production of osteoarthritic chondrocytes during cartilage regeneration was higher than that of healthy and defect chondrocytes (P < 0.001). Adding IL-6 increased GAG production by healthy chondrocytes and decreased GAG release by osteoarthritic chondrocytes (P < 0.05). Inhibition of IL-6 present in osteoarthritic synovial fluid showed a trend towards decreased GAG content of the explants (P = 0.06). CONCLUSIONS: Our results support a modest anabolic role for IL-6 in cartilage matrix production. Targeting multiple cytokines, including IL-6, may be effective in improving cartilage repair in symptomatic cartilage defects and osteoarthritis.

Fate of the ulnar nerve after operative fixation of distal humerus fractures.

OBJECTIVES: It is well recognized that operative treatment of a fracture of the distal humerus requires handling of the ulnar nerve, which can cause nerve dysfunction; however, the incidence of postoperative ulnar nerve dysfunction is not well studied. Our purpose was to determine the incidence of ulnar nerve dysfunction after open reduction and internal fixation of distal humerus fractures and identify factors associated with its development. DESIGN: Retrospective cohort study from two university-based institutions. PATIENTS: The medical records of 69 patients with a minimum of 12 months follow-up (median, 15 months; range, 12-72 months) after open reduction and plate and screw fixation of a bicolumnar fracture of the distal humerus (Orthopaedic Trauma Association Types 13A and C) that did not have preoperative ulnar nerve dysfunction were reviewed retrospectively. INTERVENTION: Surgical repair of a distal humerus fracture with or without ulnar nerve transposition. MAIN OUTCOMES: Ulnar nerve function was graded immediately postoperatively and at final follow-up according to a modified system of McGowan. Those with and without ulnar neuropathy were analyzed for differences in final position of the nerve (anterior versus in the cubital tunnel), open injury, multiple procedures, ipsilateral injury, and demographic factors. RESULTS: : The incidence of immediately postoperative ulnar nerve dysfunction documented in the medical record was seven of 69 patients (10.1%) (McGowan grades: 1 [57%], 2 [43%], 3 [0%]). The incidence of ulnar nerve dysfunction at final follow-up was 16% (11 of 69 patients) (McGowan grades: 1 [72%], 2 [28%], 3 [0%]). No demographic, injury, or treatment factors were associated with a risk of postoperative ulnar nerve dysfunction. CONCLUSION: There is a substantial incidence of postoperative ulnar nerve dysfunction after open reduction and plate and screw fixation of the distal humerus, which is likely underestimated by this retrospective analysis. Prospective studies using careful preoperative nerve evaluation and systematic postoperative nerve assessment are likely to identify an even higher incident of postoperative ulnar nerve dysfunction. Transposition was not protective in this analysis.

Cytokine profile of autologous conditioned serum for treatment of osteoarthritis, in vitro effects on cartilage metabolism and intra-articular levels after injection.

INTRODUCTION: Intraarticular administration of autologous conditioned serum (ACS) recently demonstrated some clinical effectiveness in treatment of osteoarthritis (OA). The current study aims to evaluate the in vitro effects of ACS on cartilage proteoglycan (PG) metabolism, its composition and the effects on synovial fluid (SF) cytokine levels following intraarticular ACS administration. METHODS: The effect of conditioned serum on PG metabolism of cultured OA cartilage explants was compared to unconditioned serum. The effect of serum conditioning on levels of interleukin-1beta (IL-1beta), IL-4, IL-6, IL-10, IL-13, interferon gamma (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), osteoprotegerin (OPG), oncostatin M (OSM), interleukin-1 receptor (IL-1ra) and transforming growth factor beta (TGF-beta) were measured by multiplex ELISA. As TNF-alpha levels were found to be increased in conditioned serum, the effect of TNF-alpha inhibition by etanercept on PG metabolism was studied in cartilage explants cultured in the presence of conditioned serum. Furthermore, cytokine levels in SF were measured three days after intraarticular ACS injection in OA patients to verify their retention time in the joint space. RESULTS: PG metabolism was not different in the presence of conditioned serum compared to unconditioned serum. Levels of the anti-inflammatory cytokines IL-1ra, TGF-beta, IL-10 as well as of pro-inflammatory cytokines IL-1beta, IL-6, TNF-alpha and OSM were increased. IL-4, IL-13 and IFN-gamma levels remained similar, while OPG levels decreased. TNF-alpha inhibition did not influence PG metabolism in cartilage explant culture in the presence of conditioned serum. Although OPG levels were higher and TGF-beta levels were clearly lower in ACS than in SF, intraarticular ACS injection in OA patients did not result in significant changes in these cytokine levels. CONCLUSIONS: ACS for treatment of osteoarthritis contains increased levels of anti-inflammatory as well as pro-inflammatory cytokines, in particular TNF-alpha, but conditioned serum does not seem to have a net direct effect on cartilage metabolism, even upon inhibition of TNF-alpha. The fast intraarticular clearance of cytokines in the injected ACS may explain the limited effects found previously in vivo.

Isolated posttraumatic ulnar translocation of the radiocarpal joint.

An isolated posttraumatic ulnar translocation of the carpus is unusual. In cases in which the translocation occurs without accompanying injury to distal radius, ulna, or carpal bones, the diagnosis is often delayed due to the unfamiliarity of the treating physician with this rare radiographical finding. By presenting two patients with such an injury, we hope to increase awareness of this injury.

Joint injury and osteoarthritis: soluble mediators in the course and treatment of cartilage pathology.

Osteoarthritis is a disabling disease of the aging generation, which results in loss of quality of life and increased healthcare costs. Cytokines appear to play an important role in the cartilaginous degeneration characterizing the pathological process. Increasing experience is being gained with cytokine-modulating therapies aimed at interfering with effects of chondrodegradative cytokines in the synovial fluid. Although in vitro and in vivo effectiveness of several of these therapies has been demonstrated, clinical effectiveness remains disputable, which may be related to the low levels of inflammatory cytokines found in osteoarthritic joints. By contrast, directly after joint trauma, which has been shown to predispose to early osteoarthritis, synovial fluid cytokine levels are strongly increased. Cytokine-modulating therapies, however, have hardly been considered for this indication. Increased knowledge of intra-articular soluble mediators correlating with cartilage pathology will lead to further development of cytokine-modulating products and, eventually, to effective inhibition of cartilage degeneration, in both the osteoarthritic as well as injured joints.

Perilunate fracture-dislocations of the wrist: comparison of temporary screw versus K-wire fixation.

PURPOSE: Temporary intercarpal screw fixation has been suggested as an alternative to temporary K-wire fixation in the treatment of perilunate wrist dislocations. We compared the 2 treatment methods in 2 retrospective cohorts with a null hypothesis that there would be no difference in final wrist motion. METHODS: Eighteen patients with surgically treated perilunate wrist dislocations (9 treated with intercarpal screws, 9 with intercarpal K-wires) were evaluated an average of 44 months after injury. The intercarpal screws were removed an average of 5 months and the K-wires an average of 3 months after the initial procedure. Complications included 3 pin track infections (1 with wrist sepsis), 2 scaphoid nonunions (screw fixation), and 2 patients with loss of reduction (K-wire fixation) treated with repeat surgery. RESULTS: Four patients (2 in each cohort) had wrist arthrodesis with poor results. Among the 14 remaining patients the final flexion arc was 97 degrees for patients treated with screw fixation compared with 73 degrees for patients treated with K-wires. The mean grip strength was 74% (screw fixation) and 67% (K-wire) that of the uninjured arm. According to the Mayo Modified Wrist Score, the functional result was excellent in 1 patient (screw), good in 2 patients (1 each group), fair in 6 patients (3 in each group), and poor in 9 patients (4 screws, 5 K-wire). Seven patients (2 screws, 5 K-wires) had grade 2 or 3 midcarpal arthritis according to the criteria of Knirk and Jupiter, but none had more than mild radiocarpal arthritis. CONCLUSIONS: The results of treatment with temporary screws are comparable to the results of treatment with temporary K-wires. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic III.