TOTAL HIP REPLACEMENT IN PATIENTS WITH FALSE JOINT OF THE FEMORAL NECK Markov D.A., Zvereva K.P., Belonogov V.N.

Saratov State Medical University named after V.I. Razumovsky, Saratov, Russia

The false joint of the femoral neck presents a severe lesion of the proximal femur which is more common for older and senile persons [2].

The etiology of formation is determined by specific type of blood flow in the proximal femur, by decrease in bone tissue mineral density and by burdened somatic status, which is more common for older patients [2].

The diagnostics is oriented to identification of the signs of formation of the false joint (a crevice between bone fragments, closure of the marrowy canal by compact substance – arch laminae), and estimation of bone mineral density [3].

Hip joint replacement in case of false joints of the femoral neck is the method of choice, which allows early load to the extremity after surgical intervention, reducing the terms of rehabilitation, and fast return to normal life with improvement in life quality [4]. A study by Rolf (2010) showed high efficiency of arthroplasty for recovery of hip joint functioning in comparison with osteosynthesis techniques [5]. However, despite of all advantages of total replacement, the percentage of poor results is very high. The common complications are prosthesis head dislocation, aseptic instability of components, and periprosthetic fractures of the femoral bone [6]. It is associated with such features as bone mineral density decrease (low or absent supporting ability of the extremity), hip joint contractures (massive scarry process), limb shortening (3-6 cm on average), and hypotrophy of muscles of the lower extremities [7].

The high incidence of complications caused the active search for features of presurgical planning and surgical techniques, which would allow improve the results of treatment of false joints of the femoral bone.

Objective – to improve the results of total hip joint replacement in patients with the false joint of the femoral bone by means of the comparative analysis of outcomes of implantation of constructions of the endoprosthesis of various types of fixation.

MATERIALS AND METHODS

We conducted the comparative analysis of results of total replacement in 102 patients with false joints of the femoral neck treated at the basis of Saratov State Medical University named after V.I. Razumovsky in 2015-2017. The mean age of the patients was 72.5 (68-79). There were 79 women (77 %) and 23 men (23 %). The mean time from trauma to prosthetics was 15 (10-18) months.

The concurrent presurgical pathology was identified in all 102 patients (100 %). The figure 1 shows the comorbid status of patients before surgery.

Figure 1

Comorbidity of patients with false joint of femoral neck before surgery

Figure 1 Comorbidity of patients with false joint of femoral neck before surgery

The surgical and anesthesiological risk was estimated as moderate – significant: 2-4.5 points (according to the classification of surgical-anesthesiological risk recommended for practical use by Moscow Research Society of Anesthesiologist-Intensivists).

The clinical examination showed the mixed contracture of the affected hip joint with maximal limitation of flexion and abduction.

Commonly, hip joint replacement was performed through the posterior-lateral approach by Moore (89 patients, 87 %), which is characterized by the highest stability by means of intermuscular gluteal approach. The anteriolateral approach by Harding was used for 13 patients (13 %) with excessive body weight to improve the visibility of surgical field.

The anesthesiology included spinal anesthesia. During surgical intervention, some technical difficulties appeared owing to evident scarry process, anatomical features, osteoporosis and significant shortening of the lower extremity.

Depending on a type of the endoprosthesis, all patients were distributed into 3 groups. The first group included 43 patients (42 %) who had received the cementless endoprosthesis by Smith and Nephew including the screwed cup by Bicon type, and SL stem by Zweimuller type.

The second group included 35 patients (34 %) who had received the hybrid type the endoprosthesis by Zimmer type: the cementless cup by Muller, and the cementless stem Spotorno by Zweimuller type.

The third group included 24 patients (24 %) with the cementless endoprosthesis: double stability cup Smith and Nephew Polar cup and SL stem by Zweimuller type.

The friction pair “head – insert” in all cases was “metal – polyethylene”.

The prevention of thromboembolic complications included the elastic bandage for the lower extremities, and injection therapy with low-molecular heparin (Clexan). In the first post-surgery day, the pain was corrected with narcotic analgetics (morphine), and, subsequently, with non-steroidal anti-inflammatory agents (Ketorolac, Nimesulid). The antibiotic prevention was conducted with wide-spectrum drugs (cephalosporins of the third generation) within 5 days after surgery. The quality of bone tissue was improved with zoledronic acid of biophosphonate group (Aklasta) at the background of administration of calcium (Ca-D3-nicomed) and D3-vitamin (Aquadetrim).

The postsurgical limitations were discussed with the treating physician before surgical intervention. The neutral position of the lower extremity (limitation of external and internal rotation) was recommended for the patients, as well as limitation of flexion to 90˚ and abduction more than 20˚ in the operated hip joint.

The physical rehabilitation consisted in prescription of respiratory gymnastics, sitting in the bed, and vertical standing with use of additional support in the first day after surgery. From the second day, the patients were trained to use the three-support walking with dosed loading (not more than 30 % – weigh-scales method) to the operated extremity. Isometric exercises for musculus quadriceps femoris and musculus biceps femoris, and flexion/extension in knee and ankle joints were recommended. From the 4th day, active and passive training of the hip joint (Artromot device) was initiated with consideration of the recommended limitations. Stair walking training was on the days 7-10 after joint replacement. Transition to walking with the cane on the opposite side was recommended after 6-8 weeks. Full refusal from additional support was recommended after 12 weeks. Recovery of full functional volume of motions was achieved by means of active and passive training with supplementary plyometric exercises.

The results of total replacement were estimated with use of clinical and radiologic techniques, and questionnaires after 3, 6 and 12 months, and then – annually. The clinical examination included the estimation of volume of movement in the hip joint. The comparative measurement of functional and anatomical length of extremities, and volume of hips and legs was conducted. Attention was given to presence or absence of signs of inflammation (redness, soft tissue edema, local temperature increase, pain during palpation, presence of fistulous tracts and purulent discharge in region of the postsurgical scar). Anterior-posterior X-ray images were used for estimation of the inclination angle of the endoprosthesis cup, condition of bone tissue in DeLee-Charnley, and Gruen zones. Pain intensity was estimated with VAS [8]. The functional results of treatment were estimated with Harris Hip Score: excellent result – 90-100 points, good – 80-89, satisfactory – 70-79, poor – < 70 [8].

The statistical analysis was conducted with Atte Stat 12.0.5 (Microsoft Corporation, USA). The results were presented as Me (IQR) in relation with rejection of the hypothesis of normal distribution of variational series, where Me – median, IQR – interquartile range, LQ – 25 % quartile, UQ – 75 % quartile. Non-parametric Mann-Whitney’s test was used for comparison of quantitative data, χ2-test (chi-square) – for qualitative data. The statistical hypothesis was considered as true at p < 0.05.

The study was conducted on the basis of the written consent, and with approval by the ethical committee in compliance with Helsinki Declare – Ethical Principles for Medical Research with Human Subjects, 2000, and the Rules for Clinical Practice in the Russian Federation, confirmed by the Order of Russian Health Ministry on June, 19, 2003, No.266.

RESULTS

The treatment results were estimated in all 102 patients (100 %). The mean period of the follow-up was 18 (16-22) months.

Total replacement estimation was initiated with clinical examination including estimation of postsurgical region, measurement of motions in the operated joint, measurement of length of lower extremities (anatomic and functional), and comparative measurement of volumes of hips and legs. The clinical signs of inflammation (redness, soft tissue edema, local temperature increase, pain during palpation, presence of fistulous tracts and purulent discharge in postsurgical scar region) were identified in 2 patients (1.9 %). Shortening of the operated extremity was noted in 7 patients (6.9 %): 0.7 (0.5-1) cm. The presurgical range of movement in the hip joint showed some statistically significant differences from the values one year after joint replacement in all study groups (the table 1).

Table 1. Range of motions in affected hip joint

Range of motion indicators	Study groups
	before THR n=102	after THR
	before THR n=102	1^st group n = 43	2^ndgroup n = 35	3^rdgroup n = 24
Flexion, degrees, Me (IQR)	48 (41 – 53)	103 (99 – 107)*	104 (100 – 110) *	108 (102 – 111)*
Extension, degrees, Me (IQR)	3 (0 – 5)	8 (5 – 10)*	7,5 (6 – 9)*	8 (6 – 10)*
Adduction, degrees, Me (IQR)	5 (3 – 8)	10 (7 – 13)*	10 (8 – 12)*	12 (10 – 15)*
Abduction, degrees, Me (IQR)	10 (5 – 15)	25 (22 – 29)*	26 (23 – 30)*	27 (24 – 30)*
External rotation, degrees, Me (IQR)	12 (9 – 15)	26 (22 – 29)*	23 (19 – 28)*	27 (24 – 30)*
Internal rotation, degrees, Me (IQR)	15 (11 – 18)	28 (25 – 30)*	25 (22 – 27)*	30 (26 – 33)*

Note: THR – total hip replacement; * - statistically significant differences between the indicators in study groups before and after THR; p < 0.05

The complications were identified in 15 patients (the table 2).

Table2. Structure of complications

Complication	Study group
Complication	1^st group n = 43	2^ndgroup n = 35	3^rdgroup n = 24
Periprosthetic joint infection, abs., (%)	1 (0,95 %)	-	1 (0,95 %)
Early postsurgical hematoma, abs., (%)	1 (0,95%)	3 (2,9 %)	2 (1,9 %)
Endoprosthesis head dislocation, abs., (%)	3 (2,9 %)	2 (1,9%)	-
Total	5 (4,8%)	5 (4,8%)	3 (2,85%)

Deep periprosthetic infection of the hip joint was registered in 2 patients (1.9 %). It was treated with two-stage revision intervention: the stage 1 – installment of the articular spacer, affluent-deflux draining, antibacterial therapy. The stage 2 included replacement of the articular spacer to revision constructs. The conducted statistical analysis did not find any significant differences in development of deep periprosthetic infection in the study groups (χ2 = 1.337, p > 0.05).

Early postsurgical hematoma in 7 patients (6.9 %) required for lytic therapy and hematoma puncture in 2 patients (1.9 %). There were not any statistically significant differences in development of early postsurgical hematoma in the study groups (χ2 = 1.700, p > 0.05).

Dislocation of the endoprosthesis head was in 5 (4.9 %) patients. Conservative reduction of the endoprosthesis head was conducted in one case. Other cases required for recurrent surgery. The statistical analysis did not find any significant differences in endoprosthesis head dislocation in the study groups (χ2 = 1.684, p > 0.05).

The analysis of X-ray images did not find any signs of instability of the endoprosthesis components in patients. The lateral inclination angle was 40 (37-42) degrees. Gradation of condition of paraprosthetic bone tissue in DeLee-Charnley zones was excellent in 24 (23.5 %) cases, good – in 72 (70.6 %), satisfactory – in 4 (3.9 %), poor – in 2 (1.9 %). Gradation of condition of paraprosthetic bone tissue in Gruen zones was excellent in 19 (18.6 %) cases, good – in 75 (73.6 %), satisfactory – in 6 (5.9 %), poor – in 2 (1.9 %).

The analysis of results of VAS showed a statistically significant decrease in the value, depending on rehabilitation duration. The highest increase in the value was noted in the first six months after surgery that supposed a decrease in intensity of pain, and recovery after total joint replacement. The time course of VAS data is presented in the table 3.

Table3. Dynamics of VAS results

Study group	VAS results
Study group	Before surgery	After 3 months	After 6 months	After 12 months
1^stgroup	8,5 (8,2-8,7)	4,3 (4,0-4,5) *	2,7 (2,5-3,0) *	1,4 (1,1-1,6) *
2^nd group	9 (8,7-9,2)	4,1 (3,9-4,3) *	3 (2,7-3,2) *	1,5 (1,3-1,7) *
3^rdgroup	8,9 (8,7-9,2)	3,9 (3,6-4,2) *	2,4 (2,2-2,6) *	1,2 (1,0-1,4)*

A clinically identified improvement in condition of the hip joint was confirmed by Harris score: excellent results – 90-100, good – 80-89, satisfactory – 70-79, poor – < 70. The presurgical values of HHS showed some statistically significant differences from functional results in 12 months in all three groups (Fig. 2).

Figure 2

Results of THR according to HHS

Figure 2 Results of THR according to HHS

The table 4 shows the results of Harris score. As the table shows, the highest amount of excellent and good functional outcomes is noted in the group 3. The poor outcomes were more often identified in the groups 1 and 2 (χ2 = 9.29, p < 0.05).

Table 4. Structure of THR outcomes according to HHS

Outcome	1^st group	2^nd group	3^rd group
Excellent, abs., (%)	7 (16,3 %)	6 (17,1 %)	5 (20,8 %)
Good, abs., (%)	19 (44,1 %)	16 (45,8 %)	12 (50%)
Fair, abs., (%)	15 (34,9 %)	11 (31,4 %)	6 (25 %)
Poor, abs., (%)	2 (4,7 %)	2 (5,7 %)	1 (4,2 %)
Total	43 (100%)	35 (100 %)	24 (100 %)

DISCUSSION

The false joint of the femoral neck is one of the most severe abnormalities of the hip joint, leading to disability and evident decrease in life quality.

Total hip joint replacement is the most efficient technique of treatment, which allows fast removal of pain, and recovery of supporting ability of the injured extremity. However, the percentage of poor outcomes is very high due to intense scarry process, bone mineral density decrease, and shortening and hypotrophy of gluteal muscles.

In this study, we analyzed the results of total hip joint replacement in patients with false joints of the femoral neck, depending on a type of the endoprosthesis and its fixation.

The highest number of good and satisfactory results of was noted in the group 3, where the patients had received the implantation of the acetabular component of dual mobility. According to our opinion, it is associated with the feature of the metal construct, which allows higher volume of movements in high stability [9]. Similar results were presented by French Association of Orthopedic Surgery and Traumatology: among 4,186 operated patients (1998-2008), 70 % of patients returned to normal life style [10].

The use of the dual mobility system also allowed decreasing the percentage of registered postsurgical dislocations of the endoprosthesis head. Reina Netal carried out a meta-analysis and showed that implantation of the standard metal constructs was characterized by high rate of dislocations (6.8 %). Moreover, the incidence of dislocations after installment of the dual mobility cup is 0.9 % [11].

There were not any cases of aseptic instability over the whole period of the follow-up. According to our opinion, it can be associated with prescription of therapy for osteoporosis, i.e. antiresorptive biphosphonates at the background of administration of calcium and vitamin D3, which improve bone mineral density and, therefore, promote the integration of the endoprosthesis components [12].

CONCLUSION

1. Total hip joint replacement in patients with false joints of the femoral neck is characterized by excellent, good and satisfactory results in 95.1 % of cases (χ2 = 9.29, p < 0.05).

2. The most common postsurgical complications are hematoma (5.75 %) and dislocations of the endoprosthesis head (4.8 %) due to evident scarry process and significant decrease in strength of gluteal muscles.

Information on financing and conflict of interests

The study was conducted without sponsorship. The authors declare the absence of any clear and potential conflicts of interests relating to publication of this article.